WO2021186136A1

WO2021186136A1 - A design for an efficient symbiotic electricity generation plant

Info

Publication number: WO2021186136A1
Application number: PCT/GB2020/000030
Authority: WO
Inventors: John Jackson
Original assignee: John Jackson
Priority date: 2020-03-17
Filing date: 2020-03-17
Publication date: 2021-09-23

Abstract

There is disclosed a fuel combustion apparatus for large-scale power generation, from a variety of commercially available fuels including recycled fuels, said apparatus comprising one or a plurality of combustion units (A, B); at least one heat extraction stage (C); and at least one heat recovery stage (D) wherein combustion products from a first combustion unit are introduced into at least one heat extraction stage (C) for further recovery of energy, and the output products of the heat recovery stage comprising cooled combustion products are fed into a cooling stage (D).

Description

A DESIGN FOR AN EFFICIENT SYMBIOTIC ELECTRICITY

GENERATION PLANT

Field of the Invention [0001] The present invention relates to a method and apparatus for fuel combustion, particularly although not exclusively for large-scale power generation.

Background of the Invention

[0002] There are various large-scale electricity power generation plants already known in the art. Improving the thermal efficiency of conversion of fuel energy to electrical energy is a primary ongoing objective of electricity power generation plant design.

Summary of the Invention

[0003] The inventor has realised that prior art fuel combustion systems for large-scale electrical power generation are wasteful of heat energy and that efficiency can be improved by making use of heat generated by combustion, which in a prior art power generation systems would normally be exhausted through the chimney to be released into the atmosphere, to pre-heat the fuel input into one or more combustion units and thereby achieve greater thermal efficiency.

[0004] Further, additional increased overall efficiency can be obtained by creating a thermal gradient between a combustion unit, a heat recovery stage, and a cooling stage to output carbon dioxide and electricity which is then used to feed into a Sabatier process which creates methane CH which can be fed back for use as a fuel in one or more combustion stages.

[0005] In one embodiment there is provided a fuel combustion system which consists primarily of one or more units so arranged to make a continuous high electrical energy output to a distributed electrical and/or high-power mechanical, continuously and related in arrangement to bring about efficiencies of heat, fuel and reduced direct emissions of combustion products to the atmosphere, not seen in prior art technology currently in use. Said units comprise singly, or multiples of the following: combustion units; and/or water electrolysis units; and/or remote water electrolysis unit; and/or heat recovery unit; and/or cooling units; and/or water cleaning units; and/or Sabatier reaction chambers process units; and/or gas separation units; and/or water removal units; and/or electricity generators, which either combined or in part can exhibit new and novel advantages over prior art technology power stations which combust fuels to supply an electrical distribution grid and/or combustion systems which provide mechanical outputs or drives for transport or other uses, and in certain variants provider excess of synthesised methane in a continuous output where a Sabatier reaction is used, to gas distribution and grid systems as shown by the schematic drawings in Figure 1 and other drawings herein.

[0006] One or more combustion units use the effect that a fuel when combust releases energy, mostly in the form of heat, which is converted to either a mechanical output through a shaft or drive such as is found in a gas turbine, reciprocating or rotary internal combustion engines, or by the rating system in a boiler, and the said steam being used to drive steam turbines and turn mechanical shafts/drive outputs, and that said mechanical shafts/crimes can be tasked with generating electricity using a conventional rotary electrical generator, and or tasked with providing mechanical power.

[0007] Further, the system disclosed herein has variants of engineering which offer an advantage over current known technology where a fuel is combusted and exhaust emissions are released to the atmosphere directly, in that substantial emissions to the atmosphere consist of the gas carbon dioxide is known that a chemical conversion, that methane is possible using a Sabatier reaction in a Sabatier reaction chamber, in which hydrogen gas is mixed with carbon dioxide gas and subjected to controlled unspecified temperatures and pressures to make methane and water. In the present embodiments and methods, the ability to synthesise of your from post-combustion emissions provides a more efficient system for combustion and reduces emissions to the atmosphere directly from such combustion systems, which presently in the prior art can only emit exhaust gases to the atmosphere.

[0008] The term combustion is conventionally defined as oxidation of the substance or fuel which takes place at a rapid rate of reaction releasing energy, mostly as heat or pressure changes due to the heat energy released, wherein said pressure changes are so confined or managed as the blues mechanical movement or force. In combustion, the main source of oxygen is as free elemental gas and in most combustion reactions, the oxygen reacts for molecular oxides and/or other substances, which can be said to be the post-combustion products, which in a single-stage combustion event or process are rooted as an exhaust.

[0009] It is further known that said exhaust combustion carry with them some of the heat energy that was produced by the combustion reaction, and that in most combustion systems currently in use, the seed is waste heat, as heat is not usually considered a fuel, as it is a product of combustion. In most single- stage combustion systems in use, this heat loss/waste of energy is considerable. In the present methods and embodiments, if waste heat from combustion is recovered and reused, then the efficiency of fuel used increases, and the reuse or optimised use of heat energy improves the overall thermal efficiency in a combustion system.

[0010] In known power stations which generate electrical power supplied to electrical distribution grids using a single-stage combustion process of boilers to raise steam to power steam turbines to drive electrical generators, only around 35% of the fuel energy combusted is converted into electrical energy. In some more modern prior art designs, been increased to 45% and in power stations that use waste heat power district heating systems, sometimes termed as combined heat and power plants or CHP, this efficiency can increase to 60% of overall fuel conversion. Heat lost as exhaust in single-stage combustion power station without a heat reuse system of a combined heat and power CHP design will lose 16% to 20% of heat energy of the fuel in the exhaust gases.

[0011] Known combustion systems which use a single-stage process of combustion either as a gas turbine or as an internal combustion engine (of the piston or rotary or reciprocating engine type), the fuel efficiency to lecture power or mechanical power is around 50% of fuel conversion.

[0012] Most known combustion systems obtain oxygen for combustion from the air, by what is termed air drafting, Air is composed of different gases including free elemental oxygen 0 gas which comprises around 21% of air, and nitrogen as a free elemental gas which comprises around 78% of air. In internal combustion engines and gas turbines, the presence of nitrogen is mechanically useful in that it enables gases expansion and pressure. A piston engine or gas turbine running with air with the nitrogen removed would run much hotter and may offer material destruction, as the nitrogen also act to remove heat build up in the engine or gas turbine. Conventionally, most gas turbines and reciprocating engines try to cool the fuel/air/oxygen mixtures prior to combustion to enable more fuel/air/oxygen to be introduced into a combustion stage your process, to give a greater expansion effects of products for and greater power output. It is convention that the oxygen required for complete combustion can be determined as an oxygen to fuel ratio, but that known air drafting systems would use more oxygen, as in combustion the free nitrogen gas forms nitrogen oxides, effectively removing oxygen from the complete oxidation of the fuel or fuels being combusted. The oxygen to fuel ratio is great for drafted combustion system attempting to attain complete combustion, than for combustion system using air with the nitrogen component removed.

[0013] Conventional knowledge is that complete combustion is attained of sufficient free options present oxidise all of the fuel, and complete combustion would release more energy or heat energy. Complete combustion would create post combustion products of gases or vapours of a much simpler chemical composition than the initial input fuel. It can also be said in convention that incomplete combustion can lead particles of combusted or partially combusted fuel as fine particles or deposits, and results in more chemically complex gases or vapours which can be harmful or toxic pollutants. Attaining a more complete combustion is a more efficient use of fuel and with some fuels, a lowering of pollutants in emissions post combustion can be achieved. High temperature combustion if also complete combustion, would create post combustion products of more simple molecules as gases or vapours.

[0014] An alternative to conventional air drafting for combustion is to use oxygen or as near to pure oxygen gas as can be obtained, and without allowing air into the combustion chamber, and so that when fuel and oxygen is ignited, this gives a sustained combustion post ignition of oxygen and fuel, and that with sufficient control of the fuel and oxygen, complete combustion can be obtained thereby releasing more heat energy or energy. Further where a gas as a fuel is combusted with oxygen, the combustion is rapid and can produce very high temperatures and/or high flame temperatures, for example, meeting methane with oxygen as a flame produces flame temperatures with parts of the flame reaching over 2000°C.

[0015] Any fuel with the carbon element component when combusted completely with oxygen releases energy and produces an oxide of carbon including carbon dioxide. Many fuels are rated using their carbon content physical chemistry and it is known that fuels with greater carbon to carbon or C-C linkages are considered to have a higher energy output when combusted, as the fuel has a greater density of carbon per unit mass or volume. It is also known that most fuels in, use in combustion are termed hydrocarbons and that this term relates to molecules containing hydrogen, oxygen and carbon elements in different ratios within the molecular structure of the fuel, which also determines many physical and chemical properties of hydrocarbon molecules. Fuels which can be combusted may also have other organic and inorganic chemistry molecules, which when combusted or combusted in oxygen and/or are subject to high flame temperatures can form other chemical molecules, post combustion. Known combustion/oxygen combustion chemistry of hydrocarbons is that the molecules form oxides, releasing heat, these oxides in oxygen combustion are conventionally carbon dioxide and water, the weather fuel as a pure hydrocarbon fuel is solid controls of hydrogen, oxygen and carbon. However very few fuels are pure hydrocarbons. Many hydrocarbon fuels and organic or inorganic chemistry fuels when combusted and/or subjected to very high temperatures form into simple substances either as elements or molecules, and the higher combustion temperatures give more molecular breakdown to elements or simple molecules than lower combustion temperatures such as those temperatures found in traditional air drafted combustion systems or combustion as compressed fuel or burning/combustion in a single mass or mass of uneven or irregular sizes. More complete combustion can be achieved in fuels of small physical particle size or freely available as a simple molecule, as the conversion to oxides which release energy is much faster if sufficient oxygen is present for complete combustion, and such a rapid rate of combustion also gives elevated temperatures per unit of fuel combusted. It is known that incomplete combustion will not release as much energy as heat, and may also not generate as many oxide molecules as well as residues of complex molecules that have not been broken down into simpler molecules or elements. It is known that such incomplete combustion products at low temperature or single-stage combustion processes all units of usually solid fuels or fossil fuels for example coal, when combusted produce residues of ash or char which are a by-product of combustion and/or are stored or converted into other materials. It is known that complete combustion is generally designed to give efficiency of output per unit fuel used, and that incomplete combustion is considered to be thermally inefficient.

[0016] In the specific embodiments and methods herein there is disclosed an efficient arrangement of putting individual combustion units in sequence to provide sequential combustion, whereby a fuel is combusted, and the products of what may be termed primary combustion unit are contained within the combustion system, in a flu which is so sealed to prevent escape or leakage of the post combustion products, and which provides a thermally efficient carriage of the post combustion products over a short distance into a combustion area of a further or secondary combustion unit. In the secondary combustion unit fuel is combusted again, in a two-stage sequential combustion process. The post combustion products from the secondary combustion stage then proceed in a contained manner either to further combustion units, or to heat recovery sections, cooling sections and/or Acer battery reaction chamber as required, or may be released to the atmosphere. Where additional units of combustion after the second stage combustion are required, they may be arranged in parallel or series, such additional units being used to have greater power output and/or to enable difficult fuels to combust more thoroughly by going through the required amount of combustion stages so that complete combustion of the fuel is can be attained. A two-stage sequential combustion arrangement may be suitable for most combustion applications, comprising of a primary stage combustion unit A, and a secondary stage combustion unit B.

[0017] A variety of fuels can combust in the combustion units, however it is preferred and advantageous that the fuel used in secondary combustion (or further units of combustion) be a gas preferably natural gas or methane. Also drawings Figure 1 show are supplied combustion units A B of a flow D1 which is methane synthesised and separated from a Sabatier reaction chamber/Sabatier reaction process. The synthesised methane of flow D1 can be used to co- fire/ cofuel with other fuels in varying amounts required, to either component A or component B of Figure 1 , it is however preferred that the flow D1 or natural gas be used solely, or as mixture to fuel secondary or further units of combustion, as this gives higher flame temperatures particularly as oxygen/methane flame from a burner. Products of incomplete combustion such as ash, char, sucked and smoke may be further combusted in a secondary stage combustion (or further combustion stages) to gain complete combustion, whereby the post combustion products of a prior combustion stage are so mixed/introduced into a subsequent combustion stage so that said prior combustion products are subjected as fully as possible to the high flame temperatures/high heat environment of the secondary combustion unit and if required further control to gain complete combustion by additional oxygen. In using sequential combustion as oxygen combustion and also a secondary combustion unit using methane and/or natural gas as a fuel, would be an efficient system for dealing with fuels that are chemically or physically difficult combust, and are used in primary combustion unit and that sequential combustion as an oxygen fuel system will produce little or no physical post combustion products such as ash, chart, salts and smoke particles if complete combustion is achieved.

[0018] The variety of fuels capable of being combusted in a sequential combustion, oxygen/fuel combustion system as fuel sources either in mixture/co- fuel/co-firing or used as soul fuel, in a primary combustion unit are but not exclusively, biomass, bio solids, heavy oil, bio oils, bunker fuel, coal, powdered tile waste streams with metal, tyre derived fuel oil, alcohols, oil, and waxes, wood waste. That this variety of fuels are able to be used gives greater fuel selection and use and enables fuels previously difficult to burn to meet pollution and environment concerns and this invention enables wastes to be used as fuels that single combustion stage technology does not as it does not completely or creates pollutants that cannot/should not be released to the atmosphere and/or toxic residues. Also high moisture fuels (above 10% moisture e.g. by a solid 30 moisture) can be combusted in sequential combustion oxygen/fuel system.

[0019] By using sequential combustion, heat contained/carried by post combustion flows/exhaust can be said to add to the heating requirements of any subsequent combustion stage and that this may reduce the fuel requirement of said subsequent next combustion state.

[0020] By using sequential combustion as an oxygen fuel combustion system that as oxygen is normally a gas that he can be transferred, by heat exchanger to preheat the oxygen prior to combustion and also that of fuel can be preheated (as required/permitted by its chemical and physical properties and/or by design of system requirements) using a heat exchanger. Elemental gases can be taken to quite high preheating temperatures and this is useful whereby the system can recover and induce such high temperatures in gases feeds off oxygen or fuel, particularly where a combustion stages fired by gases oxygen and a gases fuel from separate feeds prior to mixing and ignition and dependent upon volumes, use could introduce heat into the combustion unit or than heat produced directly from combustion, and lower the fuel requirement of such a combustion stage.

[0021] In Figure 1 , component F the device/system using combustion will require a supply of oxygen for combustion/boxing combustion/sequential combustion oxygen system and that this is preferred to come from the electrolysis of water, electrolysis so defined as passing an electrical voltage/current between an anode electrode and a cathode electrode suspended within an electrolyte (and/or other definition of electrolysis), which being composed of oxygen and hydrogen atoms as H₂0 that said H₂0 when electrolyte will produce hydrogen and oxygen gases as products. The supply of oxygen may also come from the separation of air, by preciously, or by other methods.

[0022] In Figure 1 , component F, the device/system in using a Sabatier reaction chamber/that you reaction process will require supplied hydrogen and that this is preferred to come from the electrolysis of water, which being composed of oxygen and hydrogen atoms as H₂0 that said Fl₂0 when electrolyte will please- oxygen gases as products. The hydrogen produced can also be used for cooling purposes and for such as a fuel. [0023] Where the said method electoral power generation is from combustion boilers to raise steam to power steam turbines and where fuels/cofiring fuel can be preheated and further wet oxygen of an oxygen combustion system (and in the air drafted combustion system variant, the air preheated) can be preheated prior to combustion stage this can reduce the fuel requirement of any combustion stage so used.

[0024] Any preheating of either fuel, oxygen, air if from waste or exhaust heat, so collected from a heat recovery section such as in Figure 1 , key as component C and drawing Figure 5i, and/or waste heat/heat produced from a cooling / cryogenic process as in Figure 1 component D and in drawing Figure 6 i) and ii), this may enable an improved thermal efficiency and fuel use efficiency compared to systems that do not recover heat and induce the heat preheat fuel/fuels and / or oxygen.

[0025] Post any final combustion stage, particularly where a high moisture fuel is used and or high amounts of water vapour present in the post combustion products flow, that the said post final stage combustion products flow will be carrying considerable heat energy, as it is convention that water has high specific heat capacity value, and that in a sequential combustion system water/water vapour could be present in high volumes or amounts. In Figure 1 , component C is a heat recovery section and component D (in part, a cooling component that can produce heat, to be recovered), where high water vapour post combustion flows are made e.g. by a high moisture fuel being combusted, the component C could recover a lot of/most of heat to any coolant/heat exchange coolant e.g. oxygen or a fuel to high temperature, the said oxygen or fuel as a coolant than carrying this heat back into one or more combustion sections. High moisture fuels when combusted in sequential combustion system enables high amounts of water vapour to be produced, which will enable (with suitable heat exchangers) a greater amount of heat to be recovered and returned to (as preheated fuel and/or preheated oxygen) to any/all combustion/sequential combustion sections. It can be said therefore that high moisture fuels when combusted can enable greater heat to be recovered and reintroduced into combustion sections/units. [0026] In removing heat, (in Figure 1 component C/heat recovery section) from any final post combustion product flow will reduce the volume of the said post final stage combustion products flow, and that if the component C is connected to a cooling section the component D/cooling section, that a continuous flow decreasing volumes attained, which will have pressure/pressure gradient and that in drawings Figure 5 ii) and iii) shows turbines powered directly by the pressure cooling and/or post combustion products flow, either as similar to a wind turbine/single propeller and/or as a turbine of multiple blade sections, similar to a gas turbine that can drive additional electrical generators or power output shafts (or multiples thereof) and the additional power outputs can be engineered compared to a combustion system that does not call post combustion product flow, creating additional electrical/mechanical power outputs than see on combustion systems that do not use heat recovery and cooling sections, and can be said to give such systems are greater electrical/mechanical power output per unit of fuel used.

[0027] In component D shown in Figure 1, is a cooling section using gas and water heat exchangers (or a combination thereof) to get the post combustion products flow in a first stage to a temperature of 0 - 5°C (Figure 6 items DG1 , DG2, DW, and D1) and remove any water vapour. This cool/cold water can be used as a coolant and then transported and/or treated to remove any physical chemical contaminants as required, and if required can be transported to the electrolysis units to be electrolyte to produce hydrogen and oxygen gases and/or can be used in ice making, and that in being able to combust a high moisture content fuel the said water vapour that can be removed, and will be greater than any combustion system that cannot combust high moisture fuels, and this recovery of water from combustion will reduce the water requirement for water electrolysis if required of the system, enabling sequential combustion systems to be located in places where less water is available and in air drafted variants (and/or variants that release post combustion product flows to the atmosphere, /do not use Sabatier reaction is to make methane) allowing water to be recovered from the combustion process as a by-product which could be used for agriculture or other uses. [0028] The electrical supply for the electrolysis of water may come from a renewable source and/or source external to the plank, but it is preferred that the design/system uses a continuous sequential combustion system and oxygen fuel combustion method, of primary and secondary combustion (or additional connected units/units of combustion that are connected either in series or parallel arrangements), whereby the steam/or mechanical power turn electrical generators to produce electricity for the use by the electrolysis unit/units to electrolyser water H 0 to its products of hydrogen and oxygen gases.

[0029] Conventionally, electrolysis systems use DC waveforms, and most supplies to and from grid networks are AC waveforms. That these waveforms are convertible using understood electrical technology control means. Herein, electrical supply and electrical flow is used in general terms without naming the waveform directly, and it is possible that an actual engineering that the waveform conversion uses could not be used and that certain units can be tasked with generators specific to the specific electrical waveform/quality required. For ease of description, in Figures 1 , items A2, A4, B2, and in Figure 4 items E1 , and E2 and in Figures 5ii) and iii) EE1 and EE2 are shown as electrical flow/supplies without specific referral to waveform type or placing of waveform converters /or specific waveform type electrical generators.

[0030] A controlled fuel or oxygen input so used to a combustion unit, can be preheated, dependent upon its behaviour chemically and physically, when so heated to elevated temperatures, so as to either a combustion and/or be a supply of energy. The heat for preheating using recovered heat from the processes, from either Figure 1 component C and/or component D, Figure 6 components DG1 , DG2, DGPS1 , DGPS2 and CYRO sections or any other suitable heat source to transfer heat, by routing the supply of fuel in containment through suitable heat exchangers, either singularly or in a concurrent/sequence to amplify the heat being carried by the pipe/supply of said fuel to supply one or a multiplicity of combustion units with a controlled flow of preheated fuel and/or oxygen. The heat so introduced may help reduce the fuel requirement, required by the design specification compared to a system of fuel combustion that does not pre-fuel to elevated temperatures and/or recovers waste/surplus heat from combustion or heat recovery or cooling sections of the process/system or part thereof. What may be termed conventionally as solid fuels/ fuels containing physical solids are thought to be able to be preheated even if having a high water content in the method of combustion termed oxygen combustion. Gases fuels that can be transported with high levels of preheating and/or transported in the absence of an oxygen/oxidative e.g. methane which has a high temperature of spontaneous combustion that such physical properties further enhance the amounts of heat that can be recovered and reintroduced into a combustion unit or multiples thereof.

[0031] The cooling component D as in Figure 1 and Figure 6 SAB contains a Sabatier reaction chamber capable of receiving a continuous flow full post final combustion stage products flow, Figure 6 as flow key G34, that is preferred to be a flow of mostly C0₂ as gas with most/all water vapour removed and also all/most non-C0₂ physical and chemical impurities removed and that the said Sabatier reaction chamber is able to mix hydrogen gas with C0₂ in a controlled and correct ratio (conventional ratio being 4 volumes of hydrogen to C0₂ at standard temperature and pressure), and that this is taken to a temperature and pressure as well mixed gases (of the Sabatier reaction varies, but is given as 300-400°C and 50 psi/345 kPa, other temperature and pressure is my views), to cause C0₂ to react with hydrogen to make CH for methane and water H₂0, which should exit the Sabatier reaction chamber in a continuous manner and proceed as shown in Figure 6 ii) DGPS1 , DGPS2, DWPS2 and DIPS2 to be cooled, but that the flow be kept at pressure (convention of 50 psi/345 kPa, other pressures may be used) until the flow can be cooled to below 2°C and/or what temperature the B compilation (sometimes called steam reformation) of CH into C0₂ is stopped, and the flow is composed of chemically stable molecules and/or any atomic gases remaining in the post Sabatier flow, which may be some C0₂ and hydrogen gases reacted in addition to CH₄ and H₂0. The said post Sabatier flow may be cooled to around 0 - 5°C in the final section DIPS2 of Figure 6 ii), and passed through direct ice to remove any water vapour and can remove some/all C0₂, by the said C0₂ being absorbed by water, the hydrogen and methane are not absorbed by water and these may pass through theDIPS2 section as gases, and also the C0₂ is heavier than hydrogen and methane and so any carbon dioxide, hydrogen and methane in a vertical column such as shown in Figure 13, will allow C0₂ to be separated out leaving the post DIPS2 flow consisting mainly of CH for and any residual/reacted hydrogen to flow to a cryogenic cooling freezing section shown as Figure 6 CYRO, where the said flow CH or an residual H₂ gases can be taken to very low freezing temperatures to liquefy the CH for component and if required the hydrogen component, but be able to draw them as separate substances required. CH liquefies at around - 160°C and hydrogen liquefies at around - 180°C, at a pressure to be specified/determined. The heat from cooling post final combustion stage and post Sabatier reaction stages and from freezing/liquidation and/or any icemaking for Dl and DIPS2 stages will be considerable and the cooling system is designed to process large volumes expected in large combustion systems efficiently in stages that can be of differing sizes/throughput as required, or rearranged as required, it be difficult to be precise on final engineering of the component stage D. Component D can produce as end product liquefied CH₄ in a continuous manner (bar any intermediate storage/balance), and such a system will produce heat more recovery to pre-heat oxygen or fuel and that the heat from the freezing/cryogenic/gas liquefying section, acts as an additional heat source, than the fuel so combusted in the system and enables heat (that may otherwise be wasted) to be used to reduced fuel used, giving a fuel combustion efficiency/thermal efficiency that other systems not having a continuous production of liquefied CH for from a Sabatier reaction are unable to obtain, as he can be used as recovered introduced back into combustion sections with fuel and/or oxygen so supplied to said combustion units.

[0032] Steam that is normally lost in boiler/steam circuits to steam turbines, sometimes referred to as “blowdown’ and released to the atmosphere, can be used in an Oxy fuel sequential combustion system by injecting it/releasing it into pre-(preferred) or post combustion flows, and this may aid water recovery thermal/fuel used efficiency. Such steam “blow downs” can be some 10% or more of a boiler’s consumption/making of steam and is known as an important loss of fuel energy in boiler steam/steam turbine energy systems.

[0033] An external source/C0₂, or multiples thereof (ideally located near to the combustion and/heat recovery section component C of Figure 1) as shown in Figure 8, such as a cement making/symmetric, is able to supply a source of heat and CO2/H2O as it is conventionally understood that cement kilns or rotary spectacles use high amounts of heat energy to convert limestone as mostly calcium and magnesium carbonates to calcium and magnesium oxide clinker which is ground into powder, using temperatures of over 800°C, would provide a heat and C0 /H 0 input to pre-or post combustion streams and/or the component C heat recovery section. The C0 from the cement kiln process would provide additional C0 to make CH for within a Sabatier reaction chamber/process and will also allow for heat recovery to be increased in the system and fuel reduction in the combustion system and reduce C0 emissions to atmosphere that occurs with current cement kiln processes and waste heat that is not recovered and used. It is understood that cement kiln energy use and emissions account for 10% of total global emissions. Further the combustion system so explained, as a sequential combustion system is of a design that offers a use of cement kiln energy and emissions to enable more efficient energy use in a system and is more efficient than current designs used.

[0034] Where an electrolysis system is a classic description/ convention/ understanding, of electrodes suspended in an electrolyte to enable a voltage/current to be passed through the electrolyte and create ions/ion transport flow/mechanism, so shown in Figure 1 and the description of the drawings as component F, that where water from ice cooling sections of component D (see Figure 6 i) D1, and ii) DIPS2 and that the said water containing dissolved/absorbed C0 , be used as part/all of the water supply for water electrolysis in component F, that by adding a salt namely calcium oxide, that this increases the number of ions and increases the efficiency of the electrolysis cell/units, reducing the electrical report crime of the cell, and that when electrolysis is occurring that this will cause the C0 dissolved in the water to form into CaC0₃ as precipitating solids on one of the electrodes and that this may be used as a building material or other use if removed from the electrolysis cell, and some of the C0 produced from the combustion can be made into CaC0₃, which is a building material, and offers a way of sequestering C0 from combustion into a useful by-product, which other combustion systems that do not have an electrolysis cell or electrolysis unit are unable to do.

[0035] A conventional single unit combustion system such as a power station making electricity to send to an electricity during distribution grid releases post combustion products/flows to the atmosphere (in some examples doing some scrubbing or emissions cleaning) and in the system herein, as a continuous contain flow of post combustion products, to heat recovery, cooling and conversion to CH /liquidated CH₄, that combustion sections may be pressurised, by a mechanical/annular/constriction or by design of the boiler combustion pathways, to enable where possible/required an increased residual time a combustion section and to enable more complete combustion, improved thermal efficiency, before exhausting to a concurrent stage of combustion or heat recovery.

[0036] The combined effect in fuel used/thermal efficiency is in certain specifications of engineering that in a two-stage sequential combustion system as shown in Figure 1 herein, that where a design is chosen which would combust solely natural gas as a pupil and/or coal-fired with synthesised methane from a Sabatier reaction, whereby fuel and oxygen is preheated using recovered heat, to the fullest extent where heat is recovered also to the fullest extent from a cement kiln/retrospective or other external source of heat/C0 , that where a second stage combustion unit/units of figurative task with generating electricity for the/an electrolysis bank/electrolysis units (although first stage and second stage, or for the stages of combusted could be tasked cooperatively or differently in supplying electricity for electrolysis of to supply the electrical distribution grid/and or mechanical drives, that the said fuel use of the secondary combustion stage could be very low compared to the fuel requirement of a single combustion unit, and that because of this low fuel use, that the said production of hydrogen and oxygen from water electrolysis utilising the power/electrical power so made and or electricity from a renewable source, this enables a combustion system that can make a mechanical/power and make in a figurative second stage combustion, the power/electrical power for the electrolysis of water, to also produce hydrogen that can be racked reacted via a Sabatier reaction, to convert C0₂ from the said combustion of all/part of the combustion units post combustion, by reacting the said C0 with hydrogen to make CH₄ methane, and that because a significant improvement in heat/thermal efficiency, compared to traditional combustion systems that are non-sequential combustion systems, that the energy so used as fuel, to make the said hydrogen is greatly reduced compared to traditional combustion systems and that because of this, it is possible that methane/CH₄ for can be so made in an excess by the system and enable conversion of part/all of the total C0₂ emission output of the system to be made into CH₄/liquefied CH₄ for (other than the portion used as fuel by the system), enabling this energy system to make a fuel in general use as CH^liquefied CH for transport or for introduction to a gas/natural gas distribution grid. This implies that such a plant/energy system would emit little or no C0₂ to the atmosphere directly and that if burning/combustion waste materials would enable a replacement for electricity power generation and/or other energy use, that currently uses so-called fossil fuels or nuclear power as materials that were previously difficult combust, can be combusted and that the system can supply energy for water electrolysis unit/units to make C0₂ emissions from not only combustion, but also from cement making into CH which is a fuel, and that further it is claimed that such a system will enable the reduction of global C0₂ emissions to be greatly reduced, as well as using a wider variety fuels that were previously out of reach/difficult combust. The embodiments here in therefore comprise a waste stream, high-temperature disposal system, and/or high-output electric generation system, and/or high thermal efficiency energy combustion system and/or continuous producer of fuel as CH^ liquefied CH from C0₂ from said combustion. It is conventional knowledge that a traditional design single combustion unit generating electricity and or mechanical power to output shafts in the functional power station, only 35 to 45% of the energy of the fuel is converted to electrical energy to distribute to the electrical grid, it is also conventional knowledge that where a more modern design station uses, waste heat as CHP unit (combined heat and power) that 60% of the energy of the fuel can be achieved. In the specific methods and the embodiments herein, as heat is recovered to use combustion system that as an electrical power generation plant it will be possible to increase the conversion fuel energy into electrical power, to electrical distribution, taking the current best efficiency of around 45% of conversion of fuel to electricity, to over 60%, and emit little or no emissions to the atmosphere making the design so outlined in this specification the most fuel-efficient, high output power stations/combustion systems currently in use in the world and also the lowest direct C0₂ emissions to atmosphere and allows for CH to be liquefied to make a fuel which could also be used to replace fossil fuels and enable further C0₂/pollution emissions cuts from the use of fossil fuels in transport.

[0037] In the embodiments and methods herein, by using a Sabatier reaction chamber, whereby carbon dioxide C0₂ gases reacted with hydrogen H₂ gas at temperature and pressure, to produce methane CH₄ and Watergate studio and that a variant as shown in Figure 12 i) herein is a satellite electrolysis unit that can supply hydrogen and oxygen via a pipe and that in Figure 12 ii) herein is shown a Sabatier reaction chamber with cooling mechanism process as shown in Figure 6 i) and ii 0 to produce methane and/or liquid methane, that receives an external C0₂ supply, but electrolysing water H₂0 to hydrogen use a Sabatier reaction chamber/process. The said oxygen so produced as shown in Figure 12 is preferably stored or used to oxygenate bodies of river, lake, marine water and may be used to remediate, clean or detoxify certain type or forms of pollution in said bodies of water, by oxidation of certain molecules/substances that are concerned with the direct toxicity of life or what is conventionally understood as biological oxygen demand of water bodies.

[0038] The specific methods and embodiments presented herein operate substantially continuously, and recover heat which would be otherwise wasted in prior art systems. Due to the continuous nature of the process, heat recovery is optimised in the specific embodiments and methods herein.

[0039] Other aspects are as set out in the claims herein, the full content of which are incorporated into this summary of invention by reference.

Brief Description of the Drawings

[0040] For a better understanding of the invention and to show how the same may be carried into effect, there will now be described by way of example only, specific embodiments, methods and processes according to the present invention with reference to the accompanying drawings in which:

[0041] Figure 1 herein illustrates schematically in overview, a combustion system according to a first specific embodiment;

[0042] Figure 2 herein illustrates schematically a simplified schematic flow showing first and second combustion components (A), (B);

[0043] Figure 3 herein illustrates schematically a schematic flow in a variant of a first combustion unit (A);

[0044] Figure 4 herein illustrates schematically a division of flows to provide even flows facilitate plant modality, to a secondary combustion component (B) a bank of electricity generators, and a heat recovery section (C);

[0045] Figure 5 herein illustrates schematically a cross-section through a heat recovery section (C) showing (i) a simple heat exchanger; and (II) and (iii) turbine powered by the flow and velocity of the post combustion flue gas products from the second combustion component (B);

[0046] Figure 6 herein illustrates schematically product flows (i) of postcombustion flue products in a cooling stage prior to a Sabatier process to remove water and; repeated (ii) after the Sabatier process to remove water and C0₂ as required, to a final cryogenic stage to separate out hydrogen and methane;

[0047] Figure 7 herein illustrates schematically a schematic view of an electrolysis bank (F);

[0048] Figure 8 herein illustrates schematically one option for introducing an external source of carbon dioxide C0₂ and/or C0₂ and water vapour and/or any heat source containing the vapours, gases, or solids which are not detrimental to the equipment or processes or operation of the combustion system;

[0049] Figure 9 herein illustrates schematically variations and modifications showing suggested arrangements of combustion components (A), (B), heat exchangers (C) and cooling stages (D) in series, and showing their modes of operation;

[0050] Figure 10 herein illustrates schematically variations and modifications showing a further arrangement of a traditional air drafted combustion unit and series connected oxygen/fuel combustion units, where the post- combustion products are transferred to sequential combustion units in a contained flue;

[0051] Figure 11 herein illustrates schematically a further design and arrangement of combustion units as a series combustion process, where primary combustion units are arranged to transfer their post-combustion group on product flows within a contained flue into a larger secondary combustion unit, according to a further specific embodiment;

[0052] Figure 12 herein illustrates schematically a remote water electrolysis plant for supplying hydrogen to feed a Sabatier reaction at a remote location, and to supply oxygen to a body of water to oxygenate said body of water;

[0053] Figure 13 herein illustrates schematically a cross-section of two different embodiments of a water/ice cooling column or vessel;

[0054] Figure 14 herein illustrates schematically an alternative is designed for a system of processing a pod post-combustion flow into carbon dioxide C0 gas and/or to a cryogenic freezing process to make solid carbon dioxide C0₂; and

[0055] Figure 15 herein illustrates schematically a large volume oxygen supply device using atmospheric air intake from a talk on structure WP which has an internal cluster of reducing height pipe takes, enabling it to be drawn in segmented heights of a vertical column.

Detailed Description of the Embodiments

[0056] There will now be described by way of example a specific mode contemplated by the inventors. In the following description numerous specific details are set forth in order to provide a thorough understanding. It will be apparent however, to one skilled in the art, that the present invention may be practiced without limitation to these specific details. In other instances, well known methods and structures have not been described in detail so as not to unnecessarily obscure the description.

[0057] In the following specific description any one or more individual technical features of one embodiment may be combined with any other embodiment described herein, except where such combination is stated as being specifically excluded, and any individual process, process stage, or step described in relation to one specific method may be introduced, substituted or combined into any other specific method described herein, except where such introduction or substitution is specifically described as excluded.

Introduction and brief description

[0058] A design for a electricity power generation plant was filed in June 2016, this utilised oxygen combustion of a fuel to produce steam to power turbines, to generate electricity, C0 from the combustion was converted into CH (Methane) in a Sabatier process .The Hydrogen and Oxygen required was generated from onsite, or piped in from remote electrolysis of H₂0 (water), using either a renewable electrical power source, or electrical power generated from the power station. Some C0₂ would be dissolved into H₂0 in the cooling process making a carbonated water which could be used as the water electrolysis electrolyte, facilitating a useful process of making CaC0O₃ (Calcium Carbonate) in the electrolysis cell when energised, by addition of CaO (Calcium Oxide) to the water, before/during use, in the electrolysis process, the CaC0₃ could be further converted into a form of cement CaS0₄, reducing emissions from cement production and giving a further economic ability.

[0059] This design in this patent application (and others related to it) is a low or even zero C0₂ emission power generation plant, primarily for the burning/combustion of Bio mass / Bio fuels/CH₄, but fossil fuels could be used also. The design can produced CH₄ via the Sabatier process for further use in combustion units of the power station enabling C0₂ from combustion of a fuel, to be converted into a fuel via a chemical reaction in the Sabatier reaction, but with a Hydrogen supply made from water as the electrolyte, using electrolysis, energised using electricity, which can be supplied by a renewable electricity generation supply, thereby enabling a low or variable renewable electrical output system, to make, a fuel for a high output and managed electrical generation system to supply an electrical grid. CH₄ can be made for distribution to the Gas grid as well as electricity to the electrical grid by electricity generation from boilers steam turbines and generators or gas turbines and generators. This design became patent application GB1613728.3 and has gone through the search process. The design noted that these power stations could be arranged in a symbiotic way to gain further efficiencies. Patent application GB1613728.3 as improved design, became GB1714707.5 which is going through the search process. This application has much of the technical and design script and drawing of GB1714707.5 and GB1801061.1 as well as some better description but gives some useful further efficiencies both thermally and in electrical power outputs and in CH outputs, which this patent application would like to apply for, using the same basis of symbiotic and series combustion as GB1613728.3, but more refined in design thinking from engineering and modality and with an explanation of the efficiency possible for difficult fuels if arranged in a symbiotic arrangement using series connected combustion units, placing the components to improve methane production, and to explain the modality better than was envisaged when filing the initial design (unpublished) that led to the patent application GB1613728.3 and GB1714707.5. Since filing GB1613728.3 I have filed a patent for an electrolysis device which I hope will improve Hydrogen and Oxygen production from the splitting of the water molecule, as in application GB1613728.3 I was conscious that water electrolysis has a number of competing of designs, so referring to it as an electrolysis bank, was a less complicated way of trying to describe the various competing water electrolysis systems, and in this application as in GB1613728.3, GB1714707.5 and GB1801061.1 reference is “electrolysis bank” meaning a device that can split and separate the water molecule, into its component elements of Oxygen and Hydrogen gases by passing an electrical current between electrodes through the electrolyte (water).The best electrolysis cell for water electrolysis, has so far achieved a 60% efficiency of electrical input into creating elemental Hydrogen and Oxygen gases, small gains are important and adding a salt can improve electrolysis cell efficiency, in this example Calcium Oxide can be used and/or other salts if suitable. The system could be run without the Calcium Oxide salt being added as in GB1613728.3, noting a way of removing any dissolved C02 in the carbonate water electrolyte, would not occur which may create a build-up of solids on the electrode or electrode erosion unless a way of removing the dissolved C02 could be achieved prior to said carbonated water being used as electrolyte in the electrolysis cell. In GB1613728.3 it was envisaged that renewable electricity would be mostly used to power the electrolysis bank, allowing for electricity from the energy plant to be used when renewables are not available, since then, with application GB1714707.5 and GB1801061.1 it may be possible for the electricity generated by the power plant (combustion) could supply enough electricity for electrolysis, however leaving the option may allow these power plants to choose and have operational flexibility, where a plentiful renewable energy such as hydro, wind or solar electricity supply is available. The energy used to make the Calcium Oxide should ideally be a renewable, however Calcium Carbonate is the basic material to make Calcium Oxide, so it could be used as a recyclable product in that CaCo3 is formed (when CaO is added to the carbonated water electrolyte in the electrolysis cell), rather than the CaCo3 being processed/converted by bubbling S02 through a CaC03 slurry (as used in some high Sulphur content coal burning power station scrubbers)to create Calcium Sulphate CaS04 as a useful building material. A further application was submitted GB1801061.1 showing a further efficiency is available from the kiln/rotary kiln method of making calcium oxide (which also be used as a salt in the water electrolysis bank), which is the widely used way of taking calcium carbonate/other carbonate type material, mostly as quarried rock and as a fine powder, which is heated to very high temperatures to drive off water and carbon dioxide, giving a sintered powder mostly of calcium oxide, which is the basic cement product as common building material. It is thought that cement making in the kiln or rotary kiln method is responsible for an estimated 10% of global carbon dioxide emissions, and it is an energy intensive process, using a lot of heat in combustion of fuels to gain the high sintering temperatures required. In the kiln and rotary kiln method of cement making, attempts have been made to recover heat, to keep energy costs down and in this application and GB1801061.1 , the heat as hot carbon dioxide and water can be used much better (as would be exiting a kiln or rotary kiln process, heating calcium carbonate, or carbonate source) by introducing the cement kiln/rotary kiln exhaust to flue products flow/stream of the series combustion units of the combustion/electricity power generation plant of this patent application and those applications related to it . To remove/reduce these carbon dioxide emissions would be helpful to climate change, carbon dioxide and/or any combustion process that emits carbon dioxide and water, could be used in GB1613728.3, GB1714707.5and GB1801061.1. Patent application GB1801061.1 sought to clarify that indirect combustion/non combustion sources of C02 or CO (carbon monoxide) could also be sources to introduce to the electricity generation post combustion (or pre combustion) feed or flue products flows of the combustion electricity generation plant e.g. brewing, chemical sources and bio digestion and bio methantion sources.

[0060] This application is related to the original design filed in June 2016 as well as GB1613728.3, GB1714707.5 and GB1801061.1 as it has an improvement and clearer explanation of some of the system possibilities/performance and refinement of operational explanation, utilising the same inventive steps of series combustion, heated oxygen and gaseous fuel inputs and use of a salt (in this example CaO) to improve water electrolysis cell efficiency and make a useful byproduct CaC0₃, and also the step of absorption of C0 into water to produce a carbonated water, separating out C0₂ where required from mixed gas flows, the CH and hydrogen separating in a simple and known process, in that H₂ and CH₄ gases are not soluble in water. Also cooling system patent application GB1711686.4 is related. This application further shows a modality in the variations and modifications section, which whilst not preferred as C0₂ is created as an end product, (in that it is hoped biomass or bio solids or bio methane or synthesised methane will be used as fuels as they are Carbon neutral fuels and not fossil fuels), offers the efficiency of series combustion with heat recovery and heated gaseous fuel/oxygen to reduce fuel use, and an alternative to converting the C0₂ to CH₄ via the Sabatier process, by making cooled or even solid C0₂, which can be used in other ways .If the Sabatier process is not used then hydrogen would not be required for the Sabatier reaction and water electrolysis would not be required, the carbonated water produced in component D would therefor need treatment to reduce acidity, by using an alkali for example, or another method of C0 removal from the water, prior to use or release to water courses. Water electrolysis may still be conducted, however the economics would then favour the Hydrogen being exported (it can be used as electrical generator coolant) for other uses.

[0061] This present application also seeks to clarify the sources of Oxygen used for combustion and/or cooling as there are choices, and the electrolysis of water produces a ratio of elemental Hydrogen and Oxygen gases, that do not always fit easily with certain plant operation modalities, as well the safety aspect of keeping combustion processes fed with Oxygen should any water electrolysis cells be subject to failure, such as electrolysis being conducted some distance from site and a pipe rupture. There is also the potential of the plant to burn problem wastes, (which could be very useful in dealing with substances that become toxic pollutants in current disposal methods) at high temperature in series combustion units to create flue products low in the toxic chemicals (that lower temperature combustion systems create), fuels such as tyre crumb or powder, waste oil sludge’s, tar residues, which are very high in actual carbon content and do not immediately form into C02 in a single combustion process (rather than series combustion process), such fuels in oxygen combustion processes, create high volumes of C02 per MW of electrical energy and put considerable demands on any post combustion Sabatier process in terms of Hydrogen required. This application also has further thinking of how the heat recovery section, component C could work to give quite high heat recovery to heat fuels or oxygen, an/or power a further steam circuit or turbine as well as flue integral flow powered turbines. The energy outputs from component C could be considerable as they are cumulative from the series combustion process of components A and B and will also be carrying considerable amounts of water vapour. Component D offers a thermodynamic relationship to component C, in that as the flue products of gases/water vapour are cooled in component D they reduce in volume, creating a lowering pressure gradient from component C to D, and a possible increase in velocity of certain flue gas product flows in component C. If flue products in component C are at high temperatures and component D pre Sabatier flows at OoC or lower then quite powerful turbines with some principals of steam turbine engineering could be used in component C as well as the more simple internal flue products stream turbines powering electrical generators shown in GB1613728.3, GB1714707.5 and GB1801061.1 .

[0062] In the larger discussion about fossil fuel use and so called greenhouse gas emissions it is clear that the main way these plants could run is to make CH and none or very little C0 (unless variation in this application is used as where C0₂ is produced and exhausted to atmosphere), the CH₄ produced is then combusted either in the electricity generation system of the plant or exported off site. Whilst requiring energy to make 0₂ and H₂ gases and energy for other operations, if a renewable/surplus electrical source and the fuel is biomass or bio methane, then the CH₄ is carbon neutral and the system can therefore be seen as sequestering some C0₂ (as CH₄) as well as fuel extension of biofuel resources and combustion fuel quantity use, giving energy resource benefits, as liquefied CH can be used as a transport fossil fuel replacement. This further means that photosynthetic fixed carbon when converted into a fuel CH₄ utilising renewable energy and/or surplus energy to provide hydrogen for the Sabatier reaction, that a useful high energy fuel, CH₄ can be made from the carbon utilised in photosynthesis, as well as generating electricity when combusted, to make the C0₂ gas used in the Sabatier reaction. By using series connected combustion units transferring post combustion products contained within a flue, to the next combustion unit, and oxygen /fuel combustion, pre heated with recovered heat, a much more efficient power station and use of fuels can be gained and this brings C0₂ outputs down .If this C0₂ is converted into CH₄ via a Sabatier reaction, then some of this CH₄ can be fed back to secondary combustion units (or primary combustion co firing), giving a high electrical output electricity generation system capable of supplying an electrical grid, from a low energy photosynthesis derived fuel source, and also renewable/surplus electricity in patterns that enable hydrogen to be made for the Sabatier reaction process. The modality enhanced in this patent application attempts to show remote water electrolysis that may be necessary in the larger system, and modality where C0₂ is produced due to the limited operation or removal of the Sabatier process. This would create direct C0₂ products or emissions from combustion which is not preferred, but shows that a hybrid system may be possible where electricity demands can be switched to electrolysis, when the demands are available, or even offer seasonal operations. It should also be noted, that solar energy, wind energy, hydro energy and nuclear energy do not dispose of waste materials, which combustion can do, this patent application making use of quantities of waste that would otherwise go to landfill, therefore enabling an efficient low C0₂ emission combustion system to still have an important part to play in the overall energy systems we use. The combustion of Biomass or other fuels in Oxygen, (rather than traditional air draughting), offers an immediate thermal efficiency improvement, in that energy is not wasted in heating the 78% of the Nitrogen (and other none oxygen gases) present in air.

[0063] Oxygen combustion also gives elevated combustion temperatures and higher velocity post combustion gaseous flue speeds, where more compact combustion areas/boilers can be used .This poses a possibility that when higher electrical output power stations 500MW and over are required, that higher flue product stream velocities and/or higher internal flue pressures, which can utilise additional turbine placements of post combustion product flows (thought about in the first design), to generate electricity. In Oxygen/ fuel combustion of organic fuels mostly composed of Carbon and Hydrogen and Oxygen, the majority of the post combustion flue products stream would be C02 and H20, which in a traditional power station would be cooled with some heat recovery, and released to atmosphere, which is in effect an energy loss (sometimes referred to as stack losses which can be about 16% of Kj of the fuel combusted) and such excess heat is rarely utilised except in urban heating systems, which are suitable for places where long cold weather periods are found. In this patent application (and related ones), these same flue products are cooled, the water vapour condensed out, and the C0 separated out and processed through a Sabatier reaction, to give a post Sabatier stream of CH , H₂0 and some C0₂ and H₂ unreacted, the water being condensed out and the residual C0₂ removed, the CH₄ produced could then be used as fuel or co firing fuel, for the concurrent series combustion sections of the power generation station, or the CH can be put to store or grid, the separated H₂ gas being fed back to the Sabatier reaction, or used for cooling, or as a combustion fuel source . The C0₂ produced (and water vapour), (post all combustion sections) if converted into CH could provide fuel to facilitate groupings of series combustion units to give higher electrical power outputs and also improved energy and thermal efficiencies compared to conventional designs, by making use of the stack losses and transferring otherwise waste heat, to enable lower fuel quantities to be used in the next combustion stage. It may be possible to pressurise some gas combustion sections by restricting the flue products flow, as fuel and oxygen can be introduced into the combustion chamber/furnace, not only at pressure but pre heated by recovered heat, methane having a high auto ignition temperature enabling said methane and oxygen to be pre heated to high temperatures of 400oC perhaps higher, giving a cycling of recovered heat back into the combustion furnace/boilers reducing fuel and oxygen requirements.

[0064] A heat recovery section would be receiving the cumulative combustion flue flow containing mostly C0 and water vapour, the water vapour providing the property of waters specific heat capacity, enabling considerable heat to be given up in, heat recovery, and potentially giving an overall efficiency in terms of electrical output, not available in current single furnace/boiler/gas turbine designs, as stack losses can be made better use of. A cooling section, which may also provide recoverable heat sources, also creates a reducing in volume of gases and water vapour, and it is possible that as a continuous process flow that velocities and pressures of internal flue product flows could be seen as gradient of high pressure going to the lower pressure of the cooling section, giving a useful flow pressure which can be utilised to directly power additional turbines and or indirectly power steam turbines from heat recovered, giving additional electrical power outputs not seen in current power station designs.

[0065] The power stations in this design would be more efficient and give greater electrical outputs than current air drafted designs, utilising the pre heated oxygen/fuel combustion plant/design without the making of CH₄ through a Sabatier process and processing the C0₂ to use or atmosphere. The use of the Sabatier process enables CH₄ to be made from C0₂ and H₂, therefore emissions of C0₂ that would in current power station design, go to atmosphere, in the design are made into CH₄, which is a fuel, effectively giving the initial fuel combusted a second life. The Sabatier reaction is heat and pressure reaction so can run in an energy efficient way. The making of elemental Hydrogen and Oxygen, from the electrolysis of water is not energy efficient requiring electrical power sources, and this poses a number of problems in balancing how much CH can be made and how much C0₂ will be not converted and need to find another route/use. [0066] Utilising an external stream of C0₂/water vapour is of use in this system and cement production is identified as being a suitable source as the CaC0₃/CaO cement sintering gives very high flue/exhaust temperatures, and contributes to thermal efficiency and combustion section fuel reduction, as well as containing C0₂ for conversion to CH₄.These plants can theoretically reduce cement emission by converting C0₂ into CH₄ and have a further use in the overall emission picture. Other external sources of heat would need consideration if they detrimentally affected equipment or process of the design.

[0067] It is understood that this design does offer higher electrical outputs and better thermal efficiency, a current modern design air drafted single 600MW coal (fuel rated at 20000Kj/Kg) burning plant using air drafting uses 350,000 kg an hour at full load or 583kg of coal per MW/ per hour, putting out 444,756 kgs/per hour of C02 or 763Kg of C0₂ per MW/per hour, other electricity production plants in current use will be less fuel efficient and produce more C0₂ per MW, and it is obvious that in using fossil fuels, the additions of C0₂ to the atmospheric gaseous balances is considerable, and having a way of converting C0₂ to CH₄ offers not only a product that can replace fossil fuel natural gas use, but acts as a buffer/store of C0₂, as CH .If using a biomass fuel i.e. made by plants from the current living biosphere, or bio gas/methane fuel, then the C0₂ absorbed by photosynthesis in the plants life, to make the basis carbon content is termed carbon neutral and combusting it does not increase C0₂ levels, in the way that fossil fuels when combusted, containing carbon sequestered/ by photosynthesis from ancient life cycles, behaves.

[0068] It is difficult to be precise on what the electricity power plants of this patent application could achieve, as other factors affect performance, but using sequential series combustion, with heated oxygen/fuel enables less fuel to be burnt and lower C0₂ outputs. There are also the higher combustion temperatures of oxygen/fuel combustion which enables some previous difficult initial stage combustion fuels, such as tyre crumb/powder to be sequentially combusted to more clean flue gases of mostly C0₂ and H₂0, it is thought that flame temperatures in a Methane/Oxygen combustion could be 2500°C or higher, adequate for complete combustion of most fuels. Being able to use more difficult fuels that may be wastes, eases the pressures of needing biomass sources and enables such electrical power stations to not use fossil fuels as well as giving an alternative to forests being used as primary biomass fuel sources. Because the water molecule splits into 0₂ and H₂, the ratio of Oxygen required for combustion, to the ratio of Hydrogen to be used in the Sabatier reaction has a number of factors in fuel and plant efficiency. These sources require managing to balance the modality of the plant unit operation and this is more difficult on the size of electrical outputs and ability and fuel choices in the combustion sections, in order to process C0₂ to CH₄ via the Sabatier reaction. It is hoped that Oxygen and Hydrogen production from water electrolysis can be done/managed on site using available imported renewable electricity resources and/or electrical outputs from the electrical generators of the plant, and or spare or surplus grid electricity. Water consumption on the plant site, can come from the water condensed out of the combustion flue product flow, and certain high moisture content fuels, that can be combusted in oxygen rather than normal air drafting, such as bio solids, offering additional water to be recovered, and it is possible that actual water requirements may be met without much on site water abstraction. Remote water electrolysis sites will need a supply of water, which may need pre-treatment prior to use as electrolyte for e.g. mineral content and may be a little less efficient without the addition of a salt to the electrolyte, but could operate in some situations reasonably autonomously and in one example route excess oxygen to feed to water bodies to dissolve into the water to oxygenate it and give a positive environmental effect to said body of water.

[0069] Continuity of combustion and flue product flows (from component A to component B to component C and to component D or multiples thereof) is envisaged to be continuous, as would be heat recovery and cooling sections, although the Sabatier process flows and cryogenic separation and CH₄ liquefication may need some separate management/buffers/stores.

[0070] In the cooling section, cold and or liquefied /gases are used for initial cooling, and then a water cooled stage and a direct contact with water ice stage, the outflow of the ice cooling stage as liquid water could be used as the coolant in the water cooling stage before being routed to the water electrolysis bank to become the electrolyte. It is thought the cooling section (component D) should be powered from a renewable, dependent upon what is available or specified for operation requirements.

[0071] Overall the thermal efficiencies, fuel/Oxygen pre heating and heat recovery and additional electrical generation turbines can give this plant much lowered/improved C0 outputs per MW as well as making CH as a fuel, however the water electrolysis does consume electrical energy and this affects calculations around sizing of electrical outputs to grid, CH₄ production, C0₂ emissions to atmosphere and use of renewables.

[0072] This application does give an electrical power station that can produce CH from C0₂, but this arrangement may need external supplies of Hydrogen and/or Oxygen using spare or renewable electricity and this requires a larger energy system conceptualisation, which is outlined in this application.

[0073] It is also possible that the post Sabatier products with the water condensed out, of CH and unreacted C0₂ and H₂ gases could be separated and liquefied into, but this cool stream of mixed gases could be used as a gas coolant and then become a fuel which (see flow G4CF key in drawings Figure 6) may give reduced energy use for liquefying and cooling post Sabatier gaseous flows as well as some modality flexibility, any C02 excess from cycling can be released through a post combustion flow cooling/water condensing flow (DICO key on drawings Figure 6) to further processing as C02 or release to atmosphere.

Introduction to drawings

[0074] Drawings and keys are referred to as components or units, as they can best be described without confusion and complexity, beginning as basic framework of the whole system or in sections which will be further described in the description. Intermediate storage of electricity or vessels to contain of hold flows of vapours/gases or other products as well as valves and reciprocating engines, boilers turbines/electricity generators, are not generally shown throughout the drawings, to make the drawings less complicated. It is assumed that heat exchangers/waste/recovered heat will pre heat Oxygen and Methane/fuel supplies to the combustion units, using recovered heat from component C and cooling heat exchangers, and/or recovered heat from ice water making and/or cryogenic processing within component D, and /or other source of heat e.g. Solar thermal, to improve the thermal efficiency of the series combustion/larger system. Drawings are also included for modifications and variations to help clarify the larger energy system explanation, supporting the patent application.

[0075] Drawings Figure 1 : A schematic view of flows of materials and energy in the power/energy generation system. There are 5 main sections key as A,B,C,D and F .Component A (or multiples thereof) is the initial combustion power plant generating electricity, Component B (or multiples thereof) is the secondary combustion plant generating electricity, Component C is heat exchange plant that may also generate electricity indirectly, removing heat from the flue gas from component B (or component A if component B is not present see variations and modifications) .component D is the continuous consequential heat exchanger, cooling process, to separate out the water vapour of the combustion processes, to liquid to give a mostly C0 gas stream and then mix and react this C0₂, with H₂ in a Sabatier process and a subsequent cooling process, to condense/remove the liquid water of the products from the Sabatier process, the remaining gases mostly of CH₄, unreacted C0₂ and H₂ then going to the cryogenic section to remove any remaining C0₂ and liquefy the Methane by cryogenic cooling, whilst leaving the hydrogen as a super cooled gas. Component F is the “electrolysis bank” where water is split and separated into its elemental gases Hydrogen and Oxygen, using electricity either from a renewable source or from the electrical power generation of components A, B or heat recovery component C. The flow of combustion products between the furnaces/boiler of A and B is shown are flows G1 , G2, and flow G3 is from the heat recovery/heat exchanger component C, to the component D cooling section, to remove the water, then the C0₂ flow and a supply of Hydrogen are mixed and processed in the Sabatier reaction, and then secondary cooling to remove the water as liquid and final cryogenic cooling section to separate post Sabatier products to make liquid CH₄, gaseous H₂.

[0076] To take each main component in turn:

[0077] Component A key is the primary combustion plant, it is fed with fuel Z or combination of fuels, this fuel is primarily envisaged as Biomass, Bio solids or recycled wood/paper/cardboard, however fuels such as Ethanol, plant and animal oils/fats, shredded or powdered tyres, waste mineral oil, or fossil fuels, or synthesised methane or natural gas or bio methane or bio gas. The products are combusted using oxygen to heat a boiler to provide steam for steam turbines or multiplicity of steam turbines to generate electricity, or if liquid or gaseous fuels can be combusted in gas turbines or multiplicity of gas turbines should steam turbines not be used, however it is envisaged that boiler and steam turbines will be a preferable energy conversion of heat to electrical energy (reciprocating engines are also possible if liquid or gaseous fuels are used in components A and B). From component F (The water electrolysis bank) we have flow F1 which is the 0₂ (elemental oxygen) flow to the burners /furnace/grate/boiler. Flow F1 can be used to assist fuel supply Z to the point of combustion e.g. blowing biomass or other fuel into the combustion zone, it can also be pre heated from recovered heat (not shown in drawings but preferred use) to improve thermal efficiency, noting also that such 0₂ may have to be dried (water removed)prior to use (drying not shown in drawings).lnput D1 is Methane (CH₄) and/or mixed gas stream which could be from the Sabatier reaction within component D or another gaseous fuel source as co firing, D1 can be pre heated using recovered heat to improve thermal efficiency (not shown in drawings) and may need to be dried (water removed) prior to use (not shown in drawings).FIow A1 is electrical flow, from electricity generated via electrical generators powered by a rotating shaft from gas or steam turbines or multiplicity of gas or steam turbines, or reciprocating engines as part of component A . Flow G1 may contain internal pipe turbines that use the pressure and velocity of the G1 flow to generate electricity (see Drawings Figure 5 ii and iii) although it is expected that this when engineered should be a short connected flue containment section, to retain heat.

[0078] Pipe or flue gas transfer system G1 should contain a hot stream of high velocity post combustion products mostly of C0₂ (Carbon Dioxide) and H₂0 (as water vapour), some ash char and unburnt products may also be present as well as some other oxides or gases. This pipe or flue post combustion transfer should be designed to cope with high temperatures and pressures, as should the construction of the furnace chamber and boilers and designed for long running time periods, it may be above ground or underground and should be well insulated to keep heat loss down.

[0079] Component B (see drawings Figurel and Figure 2) receives the post combustion flue gas products of component A via connected flue pipe/conduit, of the post combustion transfer system G1 where it is distributed to the combustion chambers/furnaces and/or gas turbines of component B (noting that reciprocating engines may possibly be used). As it is hot this aids thermal efficiency for steam production/boilers and steam turbines and may give some assistance to gas turbines. Oxygen is supplied via flow F1 (this may be pre dried and pre heated using recovered heat not shown in drawings). Flow D1 is Methane which may be from the Sabatier process of component D or natural gas/methane (this may be pre dried and pre heated using recovered heat not shown in drawings) to improve overall thermal efficiency. Feed Z is alternative fuel source if required. The natural gas/ Methane CH^fuel Z is combusted with Oxygen 0₂, (and the flue products of component A), as either in gas turbine or multiplicity of gas turbines system to make electricity or a boiler or multiplicity of boilers to make steam, to power steam turbines or multiplicity of steam turbines to make electricity from electrical generators powered by a rotating output shaft of said steam turbine or gas turbine (turbines and electrical generators not shown in drawings noting also that reciprocating engines may possibly be used).

[0080] The post combustion products from either gas turbine or furnace/boiler flue products are symbolised as flow G2 which is a pipe transfer system containing post combustion flue products, consisting mainly of C0₂ (Carbon dioxide) and H₂0 (water vapour) and some ash/ char and unburnt products may be present as well as other gases or products. Flow G2 may contain internal pipe turbines that use the pressure/ velocity of the G2 flow to generate electricity (see Drawings Figure 5 ii and iii) although it is expected that this when engineered should be a short section to retain heat. This pipe or flue post combustion transfer should be designed to cope with high temperatures and pressures, as should the construction of the furnace chamber and boilers and designed for long running time periods, it may be above ground or underground and should be well insulated to keep heat loss down. [0081] Flow B1 represents the flow of electricity from either gas turbine or multiplicity of gas turbines or boiler steam powered turbines or multiplicity of steam powered turbines with a rotating output shaft, to power electrical generators to make electricity (noting also that reciprocating engines may be possible).

[0082] Component C and Drawings Figure 5

[0083] Section i) shows a schematic flow of flow G2 (post combustion flue products stream from component B or component A if B is absent) into component C or multiple units or subdivisions of component C, which is a heat exchanger or multiplicity of heat exchangers, to remove heat from the flow G2 and/or an internal turbine or multiplicity of turbines to use the pressure velocity/velocity of the post combustion products of flow G2 from component B (and/or flow G1 from component A if component B is absent).The heat extracted/recovered being used to either power a further gas/air turbine or multiplicity of gas/air turbines or heat water in a boiler or multiplicity of boilers to raise steam to power a further steam turbine or multiplicity of steam turbines (not shown in drawings) or to be used as recovered heat elsewhere in the full system e.g. pre heating Oxygen or Synthesised Methane or natural gas/methane, prior to combustion in components A or B or multiples of A or B (not shown in drawings). Key CW is the pipe wall containing the post combustion flue products G2 (or G1 if component B is absent and component A is connected to component C), a counter current internal heat exchanger in series as key CE1 , CE2, CE3 and CE4 (more or less heat exchangers may be used), flow G2 (or G1 if component B is absent and component A is connected to component C) passing through or around, heating the external surface of the heat exchanger, transferring heat to a flowing internal material, in a counter current manner, and separate from (perhaps pressurised) the post combustion flue products flow G2 (or G1 if component B is absent and component A is connected to component C). By using a counter current heat exchanger should enable higher heating of the coolant material shown exiting the combustion flow products pipe wall as key CO, flow CO then going on to power either a gas/air turbine or multiplicity of gas/air turbines with a rotational output shaft to power generators to make electricity or heat a boiler/s to make steam to power a steam turbine or multiplicity of steam turbines with a rotational output shaft to make electricity, or reciprocating engine or multiples of reciprocating engines, with an rotational output shaft to power an electrical generator or to pre heat fuel and oxygen supplies for components A and B or multiples thereof (not shown in drawings). Flow CO once its heat is transferred returning to the heat exchanger system as key Cl flow.

[0084] Figure 5 ii) cross section shows a single turbine key as T (overhead and side view) within the post combustion flow G2 (or G1 if component B is absent and component A is connected to component C) very similar to a wind turbine. Key CW is the pipe wall containing the post combustion products, the gases and vapours strike the turbine blade surface, so designed to rotate in one direction, to drive a belt/rope/chain or hydraulic pump key PT, to transfer the rotational power through the combustion flue products wall (but keeping internal pressures/products within the post combustion flue gas pipe/transfer system), to drive an electricity generator key GN to make electricity flow E1.

[0085] Drawings Figure 5 iii) cross section shows a more complex multiple section turbine, key T, which would look like a multiple blade, gas or steam turbine, which may make better use of the pressure, this taking the rotational power of the turbine T, through a shaft (but keeping internal pressures/products within the post:

[0086] Combustion flue gas pipe/transfer system), key PT, to drive an electricity generator key GN to make electricity output shown as flow E1.

[0087] Component D and Drawings Figure 6 receives the post combustion flue gas products flow from component C (see drawings Figure 1 ) as flow G3, which having some heat removed in component C, should be ready for cooling to remove the water vapour .Drawings Figure 6 show stages within component D, starting with post combustion flow G3, entering heat exchanger DG1 , which is cooled by gas (either CH , 0 , H₂ or C0₂) the coolant gases entering into the heat exchanger DG1 as flow GI1 and exiting the heat exchanger as G01.

[0088] Flow G31 then exits DG1 and passes through heat exchanger DG2 which is cooled by gas (CH₄, 0₂, H₂ or C0₂), the coolant gases entering into the heat exchanger as flow GI2 and exiting the heat exchanger as flow G02. [0089] Flow G32 then exits DG2 and enters heat exchanger DW, which is water cooled heat exchanger which should cool flow G32 to around 10°C. The coolant water (or chilled water not shown in drawings) enters into the heat exchanger as flow Wl and exiting the heat exchanger as flow WO which may then flow to the water electrolysis bank component F (not shown in drawings Figure 6).

[0090] Flow G33 then exits DW and enters a further cooling stage Dl where water Ice (formed from demineralised water if required) is introduced as input DMII, as cube or flake or crushed or other physical form, in the top of vessel, in a way that keeps pressure integrities of the containment walls of flow G33, flow G33 coming into direct contact with the ice allowing for the water vapour to condense out and become liquid water, and exit the vessel as output W02, and absorb some of the C0₂in flow G33, to create carbonated liquid water which then may be used, either as a direct feed to the water electrolysis bank component F (not shown in drawings Figure 6), or used as cooling water for the DW heat exchanger as coolant feed flow Wl, the water may contain some combustion products e.g. flecks of char/ash or molecules of other substances which may require removal (not shown in drawings Figure 6). The mostly C0₂ vapour that now composes flow G34 (as the water has been removed) exiting section Dl is cool at around 0-1 OoC .The option to remove C0₂ at the Dl section is shown by output key DICO, which enables C0₂ gas to be managed, which could be to atmosphere or to go onto further processing to be made into low temperature solid C0₂ or other use. The flow G34 now mostly composed of C0₂ gas and a little water vapour and other combustion flue products, is cool at 0-10°C, and can be stored (not shown in drawings Figure 6), and then moves into a Sabatier process section key SAB where it is mixed with hydrogen gas fed by flow H₂ at a ratio 1 volume of C0₂ gas to 4 volumes of Hydrogen/H₂ gas (or whatever volumetric ratio is required mixing at same temperature and pressure), pressurised and heated (to 50psi /345kilopascals and 300-400°C or other pressure temperature combination as required) to facilitate the Sabatier reaction, where C0₂+H₂ is converted into CH gas and H₂0 water vapour, and some unreacted Hydrogen gas and C0₂ gas, as the process is not 100% efficient. The heat from the Sabatier reaction can be recovered in a heat exchanger process (not shown in drawings Figure 6), but may also require additional heat inputs key EN, which may come by electrical heating from on site or renewable electricity supplies to site, or from steam or heat recovered in components A, B, C or D (not shown in drawings Figure 6) or other source of heating .The post Sabatier reaction products flow becomes flow G41 should be cooled to less than 200°C whilst at pressure(to 50psi /345kilopascals or other pressure temperature combination as required) and it is hoped the process will have a incorporated heat exchanger process where the exit flow of the Sabatier reaction heats the incoming flows of H₂ and C0₂ to get reactants exit flow G41 , to below 100°C .

[0091] The post Sabatier reaction flow G41 consisting of CH₄ gas, H₂0 vapour and some unreacted C0₂ gas and H₂ gas, must now go through another cooling stage similar to that as described above (although some stages can be removed if required for process operational efficiency as the volumes to be cooled are smaller, not shown in drawings Figure 6). Key DGSP1 which is a gas cooled heat exchanger (cooled by either C0₂, CH₄, H₂ or 0₂ gases), gas coolant input being via GIPS1 and exiting the heat exchanger by GOPSI.Flow G42 then flows to a second gas cooled heat exchanger DGPS2 (cooled by either C0₂, CH , H₂ or 0₂ gases), gas coolant input being via GIPS2 and exiting the heat exchanger via GOPS2. Flow G43 then flows to a water cooling section heat exchanger DWPS2 which aims to bring the flow G43 to below 10°C to bring any water vapour to condensing to a liquid, coolant water input is via WIPS and exits the heat exchanger via WOPS. Flow G44 then continues to a water ice cooling section where water ice (preferably demineralised water), is introduced as input DIPS either as crushed, flaked or cubed ice, in a way so as to keep the pressure integrities of flow G44, flow G44 coming into direct contact with the ice. In this section of ice cooling, water vapour in flow G44 should be condensed out into liquid water. C0₂ is absorbed by the water creating a carbonated water, which exits the section DIPS2 as flow W02PS and can be used as either coolant water for water heat exchanger feeds WIPS or Wl or as feed to the water electrolysis section F of drawings Figure 7. It is possible that dependent upon size of section DIPS2 and throughput, that all C0₂ gas present In G44 entering this section can be removed by absorption into the ice and iced/condensed water, leaving as exit flow G4C of DIPS2 composed of CH₄ and unreacted H₂ gases, which are not absorbed by water and pass through as molecular and elemental gases respectively. However it may be that not all the C0₂ can be absorbed into the water, water ice melt and this C0₂ may require removal before or during the cryogenic freezing section.

[0092] Flow G4C being composed of CH₄ and H₂ gases and the water vapour condensed out (if the water vapour is not condensed out some drying may be required not shown in the drawings), then flow into a cryogenic freezing/cooling section key CRYO which is powered by energy input EN1 (most likely electrical energy, powering gas or refrigerant compressors and should be renewable such as e.g. solar or wind power collected on site), with a coolant circulation as HC as the coolant inflow and HO as the coolant outflow, HO having a heat exchanger (not shown in drawings) to extract heat that can be used elsewhere in the system e.g. for pre heating fuels or Oxygen. The cooling of flow G4C to very low temperatures (-160°C or lower or whatever temperature pressure combination is required) to liquefy the CH gas, is a way of separating the H₂ gas from the CH₄ gas, the H₂ gas requiring a lower temperature to liquefy and it should be possible to remove as super cooled H₂ gas into flow/store output key H, and remove liquefied CH into flow store output key CH. Flow output CO from the CRYO section is an option to remove C0₂ (equipment to remove the C0₂ not shown in drawings Figure 6, which may be as gas, liquid or solid) should it not be possible to remove all of the C0₂ in the DIPS2 section, and could be used as gaseous coolant in component D or reused in the Sabatier reaction section SAB, or released to atmosphere (not shown in drawings). Output H from the CRYO section as super cooled gaseous hydrogen (it could be a liquid if equipment will allow the super low temperatures), this could be used (not shown in drawings) as coolant for the electrical power generators, or coolant in sections of component D and then be reused, in the in feed H₂ of the SAB section, or it could be used as fuel for the combustion sections A and B or as a coolant for the electrical generators, it is however felt, that as fuel for combustion this in overall energy efficiency of the whole process, may not be useful, flow H could need additional drying for some applications (not shown in drawings). [0093] The CH outflow from the CRYO section as a super cool liquid CH can go to store, which may be useful for some modes of operation, where the storage of liquid CH₄ is required; however a portion can be used to fuel the combustion sections A and B, and dependent upon the C0₂ outputs entering component D via flow G3 and the scope of the Sabatier requirements and dependent upon the engineering design requirements, can enable some flexibility as to how much CH₄ is required to go to store versus how much is required for combustion as fuel in components A and B .Flow CH from the CRYO section can also be used as coolant in component D, and then be processed to standards (which may involve drying and addition of products such as an odour), to input into any gas grid network (not shown in drawings), this makes use of the heat removed by cooling to a liquid, by using the CH₄ gas as a coolant to sections of component D where heat exchange can then bring it to heat levels for export via the grid network, or higher heating, as pre heated fuel for components A and B.

[0094] Component D can offer continuous cooling of post combustion products (and pre heating of CH₄ and 0₂ as combustion units inputs), to a continuous Sabatier reaction, to further cooling and removal of any unused C0₂, before continuous cryogenic cooling to separate the CH₄ as a liquid and H₂ as a super cooled gas. It may be that some intermediate stores are required (not shown in drawings) in certain sections of component D or of certain product outflows or coolant in feeds to achieve the balances of continuous flow, however this way of processing attempts to make use of thermal energy of cooled gases, to cool the incoming post combustion flow of G3, as well as using water ice cooling sections to condense out water vapour, the said cool or chilled water from the water ice cooling sections can be used in the water cooling sections of component D giving further thermal efficiency, noting that the heat contained in flow G3 as it enters component D could be considerable due to the water vapour present in the post combustion flows, it is believed that as a cooling component overall, component D will have to be capable of cooling large volumes of vapours and gases and offer high heat efficiency/thermal efficiency due to these large volumes requiring cooling. Heat recovery from component D to pre heat fuels and/or Oxygen feeds for combustion, adds an important and innovative dimension to thermal efficiency, making use of heat losses in conventional power stations to directly heat the combustion sections A and B and in particular with boilers raising steam for steam turbines, offers an improved fuel combusted reduction, not available in current conventional power station/engine designs. This concludes the drawings to show the main components and process flow and the application will now show the introduction to drawings as Figures 1 to 14.

[0095] Drawings Figure 1 schematic diagram of whole system

[0096] Key

[0097] A=primary combustion section fed by fuel Z and or combination of fuels and/or Dried Methane fuel supply D1 , oxygen supply F1 possibly at High internal pressures and feed temperatures, and post combustion flue product flow G1. Heat recovered or steam from A shown as S1 (which could be steam drum blow down from steam turbine circuits), and be used as waste/recovered heat or introduced into flow G1 to aid thermal efficiency.

[0098] B=secondary combustion section fed by fuel Z and/or D1 (preferred dried methane/CH₄ gas), oxygen supply F1 and post combustion stream G1 from primary combustion component A possibly at high internal temperatures and pressures. Heat recovered or steam from B shown as S2 (which could be steam drum blow down from steam turbine circuits), and be used as waste/recovered heat or introduced into flow G2 to aid thermal efficiency. The post-secondary combustion products stream from B is G2.0r multiplicity of B components.

[0099] C= Heat exchanger or multiplicity of heat exchangers to recover heat to give flow S3, and/or integral flue turbine or multiplicity of integral flue turbines (not shown in drawings Figure 1 ) powered by the velocity/pressure of the direct flow of products, to power electrical generators to give electrical flow C1. Flow S3 is recovered heat which can be used for Oxygen and fuel pre heating or to power external turbines as air flow turbines or to raise steam for a steam turbine, to power electrical generators to then produce electrical flow C1. G2 inflow to component C becoming outflow G3.

[0100] D=Cooling of post combustion product flow G3 to remove water, then to process in a Sabatier reaction, fed by Hydrogen supply F2, flow D2 is hydrogen recovered from the final cryogenic process, if re used back into the Sabatier process or as flow D02 to other routes/uses for recovered Hydrogen gas such as electrical generator cooling. Flow W4 is water in feed of filtered, demineralised water for ice making and cooling, Flow W1 is carbonated water from the water/ ice cooling sections to flow to the electrolysis bank. Flow D4 is the CH gas/liquid from the Cryogenic separation process for use as fuel or to store or any other use e. g. cooling. Flow D1 is the direct flow of dried Methane/CH₄ for use in component B secondary combustion as flow D1 and/or component A primary combustion as flow D1. Flow key C0₂ is any C0₂ as gas/solid/liquid that can be separated and re used in Sabatier process or other use. Flow A4D is electricity input preferred to be from a renewable source.

[0101] A1=flow of electricity from component A produced by combustion of fuel Z with Oxygen flow F1, by either reciprocating engine, with rotational output to rotate an electricity generator, gas turbine or multiplicity of gas turbines to power electricity generators or boilers, to make steam to power steam turbines or multiplicity of boilers and steam turbines to power electricity generators (not shown in drawings). Electrical flow A2 to supply electricity to the water electrolysis bank, or to flow A3 to the electricity distribution grid system. Flow A4 is electricity from a renewable source such as solar energy, wind energy or hydro energy if required.

[0102] B Iⁿflow of electricity from component B (produced by combustion of fuel D1 or fuel Z, with Oxygen flow F1 , by either reciprocating engine powering electrical generators, gas turbine or multiplicity of gas turbines to power electricity generators or boilers, to make steam to power steam turbines or multiplicity of boilers and steam turbines to power electricity generators not shown in drawings). Flow B2 to supply electricity to the water electrolysis bank within component F, flow B3 to the electricity distribution grid system.

[0103] C1=flow of electricity from flue integral turbine or multiplicity of turbines powered by pressure/velocity of post combustion stream G2, to power an electricity generator or multiplicity of generators and/or external turbines as air flow turbines or to raise steam for a steam turbine, to power electrical generators to then produce electrical give additional electrical power to give electrical flow C1. (Boilers and turbines and electricity generators not shown in drawings Figure 1 ). [0104] Component F= the electrolysis bank, powered by electricity sources flows, A2, A4 and B2.electricty flows, electrical flow C1 could also be used to power the water electrolysis bank (not shown in drawings). Flow F1 is the oxygen produced from the electrolysis splitting of water into its component elemental gases, this flow should be pre heated from recovered heat or by using the Oxygen as coolant in component D (not shown in drawings Figure 1 Hydrogen the oxygen may also be dried if required). Flow F3 is Calcium Carbonate CaC0₃ removed from one of the electrodes within the electrolysis cells, created by Calcium Oxide (feed CA) reacting with C0 dissolved in water to give electrolysis cell electrical efficiency improvement, and precipitate out the dissolved C0₂ in the water electrolyte if required. Flow F4 is Calcium Sulphate CaS0 (the Calcium Carbonate treated with Sulphur dioxide gas) if required. Flow CA is Calcium Oxide added to water in feed W1/W2 to be used in the water electrolysis bank. Flow C031 is C0₂ gas from making the Calcium Sulphate CaS0₄ slurry; the C0₂ can be cooled and used for cooling and/or sent to component D for use in the Sabatier process for conversion into CH (not shown in drawings).

[0105] Supply flow AS = gaseous air to supply separator/store for oxygen, separated from air, stored as gas and/or liquid. Key SSO (or piped Oxygen flow from offsite electrolysis units or other method of producing Oxygen). Unit SSO then feeding flow F1 (requiring pre heating from recovered or waste heat not shown in drawings).

[0106] Supply F2 is Hydrogen gas from the water electrolysis within component F. Key SSH is supplementary Hydrogen supply (or process) from offsite electrolysis units or other method of producing hydrogen gas. Flow F2 then supplying the hydrogen for the Sabatier reaction contained within component D.

[0107] Flows G1 , G2 and G3 will be in contained pipes or transfer system capable of withstanding high pressures and temperatures and be insulated.

[0108] Drawings Figure 2 simplified Schematic flow showing combustion components A and B: Key (see also above Drawings Figure 1 for detailed explanation of key labels) Component A or multiplicities thereof fed by fuel Z and/or combination of fuels and Methane fuel flow D1 (if required), oxygen supply F1, electricity output A1. Post combustion flue products flow G1 to secondary combustion component B or multiplicities thereof, where fuel D1 and/or fuel Z (preferred as pre heated from waste/recovered heat sources, Methane /CFU/natural gas but could be co fired with other fuels) is combusted with oxygen from flow F1 (which is also preferred as preheated from waste/recovered heat sources). Post combustion flue products from B forming flow G2. Electricity produced as described in previously in drawings Figure 1 as electrical flows A1 and B1.

[0109] Drawings Figure 3 showing a schematic flow of a variation of component A discussed further in modifications and variations section.

[0110] Key

[0111] Z= fuel source

[0112] D1= Methane supply, possibly dried and heated using recovered heat.

[0113] Z1 = fuel source and/or mixed with pre heated oxygen or methane

[0114] F1=pre heated oxygen supply (from water electrolysis bank component F not shown)

[0115] A=combustion chamber to provide heat energy for boilers or multiplicity of boilers to raise steam.

[0116] S1= steam from boiler to power steam turbines section T or multiplicity of steam turbines.

[0117] S2= steam return from steam turbine or multiplicity of steam turbines section T back to boiler to be re heated.

[0118] T=Steam turbine and electricity generator or multiplicity of turbines and electricity generators.

[0119] A1 =electricity flow from generators to further use or to electricity grid.

[0120] G1A=outflow of post combustion stream from combustion section A, with ash/char other particulates.

[0121] A2=Separation system to remove, ash/char or other particulates.

[0122] G1=post combustion flue gas flow from section A2 (to section B or

C)

[0123] WS=Flow of ash/char other particulates to slurry tank SL. [0124] SL=ls slurry tank containing particulates from combustion and CaCo3 from electrolysis bank as flow F3,flow S22 adding sulphur dioxide gas, to create CaS04 exiting the slurry tank as flow F4.C02 produced in the process exiting the slurry tank via flow C031. [0125] S22= Sulphur dioxide gas supply to be bubbled through the

CaC03/ash/char/particulates slurry.

[0126] F4=CaS04 outflow from slurry tank

[0127] C031=C02 outflow from reaction of S02 with CaC03 in the slurry tank. [0128] F3= CaC03 slurry input to the slurry reaction tank from the water electrolysis bank.

[0129] Drawings Figure 4 showing schematic division of flows to provide even flows and facilitate plant modality, to secondary combustion component B, bank of electricity generators and heat recovery section C. [0130] Key

[0131] G1=combustion products flow from primary combustion component A.

[0132] B= component B with manifold to create multiple streams in this example 6, but more or less units could be used. [0133] B1=1st boiler, steam turbine and electricity generator or gas turbine and electricity generator feed and combustion unit.

[0134] B2=2nd boiler, steam turbine and electricity generator or gas turbine and electricity generator feed and combustion unit.

[0135] B3=3rd boiler, steam turbine and electricity generator or gas turbine and electricity generator feed and combustion unit.

[0136] B4=4th boiler, steam turbine and electricity generator or gas turbine and electricity generator feed and combustion unit.

[0137] B5=5th boiler, steam turbine and electricity generator or gas turbine and electricity generator feed and combustion unit. [0138] B6=6th boiler, steam turbine and electricity generator or gas turbine and electricity generator feed and combustion unit. [0139] G2=collected post combustion flue gas flows from B1 , B2, B3, B4, B5 and B6.

[0140] E1 =Electricity flow from electrical generators of component B.

[0141] C=component C with manifold to create multiple streams in this example 3, but more or less units could be used.

[0142] C1=section of heat exchanger and /or additional turbine/s powered by the pressure/velocity of post combustion flow, receiving part of the divided post combustion flow from G2.

[0143] C2=section of heat exchanger and /or additional turbine/s powered by the pressure/velocity of post combustion flow, receiving part of the divided post combustion flow from G2.

[0144] C3=section of heat exchanger and /or additional turbine/s powered by the pressure/velocity of post combustion flow, receiving part of the divided post combustion flow from G2. [0145] E2=electricity generation from turbines powering electricity generators.

[0146] G3=post component C1 , C2 and C3 sections manifold, to collect the post combustion flue gas flow exiting from C1 , C2 and C3.

[0147] Drawings Figure 5 Cross section through sections of C showing i)simple heat exchanger and ii) and iii) turbine powered by the flow /velocity of the post combustion flue gas products from component B.

[0148] Key (see also description of component C above)

[0149] Counter current heat exchanger to extract heat for e.g. pre heating of Oxygen or fuel feeds, and/or to provide steam for a separate steam turbine, the rotational output shaft turning an electrical generator to make electrical power.

[0150] G2=post combustion flow/flue products of B or sections of B or flow G1 post component A if B components are not used.

[0151] CW=wall of containment Flue

[0152] Cl— external heat exchange input flow suggested as being steam, but could be other substances.

[0153] CO=external heat exchange output flow suggested as being steam, but could be other substances. [0154] CE1 -CE2-CE3-CE4=heat exchanger surfaces through which flow Cl takes heat from flow G2 to exit as flow CO.

[0155] ii) Turbine design (overhead and cross sectional views) as similar to single rotor with mechanical power output to power an electrical generator whilst keeping the flue products flow G2 at pressure.

[0156] G2= post combustion flow/flue products of B or sections of B or post component A if B components are not used.

[0157] CW=wall of containment Flue.

[0158] T =single rotor turbine.

[0159] PT=power transfer, chain, rope, pulley or hydraulic drive, transferring power through the flue wall containment to create a rotational output at the end.

[0160] GN=electricity generator powered by the rotational output shaft of PT.

[0161] E 1 = electrical output of electricity generator.

[0162] iii) velocity/pressure multiple rotor turbine internal to flue products flow, to power an electricity generator external to the flue products containment.

[0163] G2= post combustion flow/flue products of B or sections of B or post component A if B components are not used.

[0164] CW=wall of containment Flue.

[0165] T=multiple rotor turbine (similar to gas or steam turbine arrangement).

[0166] PT=power transfer, shaft carrying rotational output, transferring power through the flue wall containment to create a rotational output at the end.

[0167] GN=electricity generator powered by the rotational output shaft of PT.

[0168] E 1 = electrical output of electricity generator.

[0169] Drawings Figure 6 showing product flows, i) of post combustion flue products in a cooling stage prior to the Sabatier process to remove water and repeated ii) after the Sabatier process to remove water and C02 (as required) to the final cryogenic stage to separate out the Hydrogen and Methane . [0170] Key see also component D section above, in introduction to drawings.

[0171] i)From component C to Sabatier reaction Flow section

[0172] G3=post combustion/post heat recovery component C products flow.

[0173] DG1=gas cooled heat exchanger with coolant inflow GI1 and coolant outflow G01.

[0174] G31=Post DG1 section product flow

[0175] DG2=gas cooled heat exchanger with coolant inflow GI2 and coolant outflow G02.

[0176] G32=post DG2 section product flow.

[0177] DW=water or chilled water heat exchanger with coolant inflow Wl and coolant outflow WO.

[0178] G33=post DW section product flow.

[0179] D water ice cooling section, where water ice input DMII is introduced into a vessel in a way that maintains any pressure integrities of the G33 containment flow/products .The ice coming into direct contact with the products of flow G33 to condense any water vapour to a liquid, this liquid then exiting through outflow W02, to be used as coolant and/or a feed to the electrolysis section. To cool outflow G34 to below 10oC (some C02 in G33 may also be absorbed into the water/ice) Heat from making the water ice may be recovered to use elsewhere in the process e.g. to pre heat fuel or oxygen feeds used in the combustion sections. It is thought that this water ice section can be short as it is trying to condense water, and not remove much C02 other than that already absorbed by the condensing water. The DICO flow is the option to remove cooled C02 gas from the Dl vessel, either for operational reasons or, to release the C0₂ to atmosphere or further processing /other use.

[0180] G34=post Dl flow consisting of post combustion products, mostly gaseous C0₂.

[0181] SAB=The Sabatier reaction section where C0₂ gas is mixed with Hydrogen H₂ gas, taken up to the temperatures and pressures necessary for C0₂ +H₂ to react to form CH₄ and H₂0 .Having hydrogen feed H₂ and energy feed EN, said energy being either heat source such as steam or electricity for heating to provide the desired reaction temperatures of 300-400°C or whatever temperature and pressure may be required to facilitate the reaction. The post Sabatier reaction flow having to be kept at pressure as required while cooling to stop steam reformation of CH back to C0₂.

[0182] G41=Post Sabatier reaction product flow which may be a mixture or CH and H₂0 and unreacted H₂ and C0₂.

[0183] ii) Flow from Sabatier process to cryogenic cooling and separation section.

[0184] G41=Post Sabatier reaction product flow which may be a mixture or CH and H₂0 and unreacted H₂ and C0₂.

[0185] DGPS1= gas cooled heat exchanger with coolant inflow GIPS1 and coolant outflow GOPS1.

[0186] G42=Post DGPS1 product flow.

[0187] DGPS2= gas cooled heat exchanger with coolant inflow GIPS2 and coolant outflow GOPS2.

[0188] G43=post DGPS2 product flow.

[0189] DWPS2= water or chilled water heat exchanger with coolant inflow WIPS and coolant outflow WOPS.

[0190] G44=post DWPS2 product flow.

[0191] DIPS2= water ice cooling section, where water ice is introduced through inflow DIPS in a way that maintains any pressure integrities of the G44 containment flow/products .The ice coming into direct contact with the products of flow G44 to condense any water vapour to a liquid, this liquid then exiting through outflow W02PS, to be used as coolant and/or a feed to the electrolysis section. To cool outflow G44 to below 10oC (some, preferably all the C02 in G44 may also be absorbed into the water/ice). Heat from making the water ice may be recovered to use elsewhere in the process e.g. to pre heat fuel or oxygen feeds used in the combustion sections. If it is better to remove the C0₂ via a cryogenic separation method then this direct contact water ice section can be short in duration. [0192] G4C=post DIPS2 flow with the water condensed out and consisting mostly of CH₄ gas and unreacted hydrogen H₂ and possibly some unreacted C02 although it is preferable that it contains no C0₂.

[0193] G4CF=post DIPS2 flow with the water condensed out, consisting mostly of CH₄ and unreacted H₂ and C0₂ (C0₂ present if water inDIPS2 section cannot absorb it), routed to fuel/co fire combustion sections of component A and B.

[0194] CRYO=Cryogenic cooling/freezing section to take flow G4C down to very low temperatures expected to -150°C to -180°C to enable the CH₄ to become liquid and the hydrogen gas to remain a gas that is super cooled.

[0195] EN1=energy supply most likely electrical to power Cryogenic plant.

[0196] HC=coolant inflow (in circulation circuit i.e. with HO)

[0197] HO=coolant outflow (in circulation circuit i.e. with HC) that could contain heat which can be removed to be used elsewhere for e.g. the pre heating of fuel or oxygen feeds for combustion.

[0198] CH=Methane /CH as a super cooled liquid (which may need drying not shown in drawings), to either go to store or to be used in cooling sections of component D and/or be heated back to a gaseous state to use as a fuel in the combustion components A and B or to be treated to be of a quality to be fed to a gas network grid.

[0199] CO=Outflow of any C02 that may or may not be removed depending upon the C02 removed by section DIPS2.This can be used as a coolant gas in component D and/or re used in the Sabatier process (or released to atmosphere not shown in drawings)

[0200] H=Hydrogen gas super cooled, which can be stored, used as a coolant in electrical generators, re used in the Sabatier process to economise on hydrogen from the electrolysis bank, or combusted in components A or B. It is believed that the efficiency is better is using it to cool the electrical generators and then using it in the Sabatier hydrogen feed.

[0201] Drawings Figure 7: Schematic view of electrolysis bank F showing

[0202] Key [0203] F=component F, the electrolysis bank, where water is split into its component elements of Flydrogen and Oxygen gases, by passing an electric current between electrodes suspended in an electrolyte (water or water and a salt).Or other water electrolysis process.

[0204] H2=Hydrogen gas separated from electrolysis cell reaction.

[0205] H3=Route for excess Hydrogen gas to exit from design for other uses which may need drying prior to export.

[0206] 02= Oxygen gas separated from electrolysis cell reaction, (preferred to be pre heated using waste or recovered heat not shown in drawings)

[0207] 03=Route for excess Oxygen gas to exit from design for other uses which may need drying prior to export. It may be used as gas coolant substance if first liquefied (not shown in drawings).

[0208] SLO=CaCo3 (calcium carbonate solids) removed from the electrolysis cells as part of reaction in energised electrolysis process, will be a slurry containing CaC03 and water.

[0209] WIS=Store of water (from component D with C02 absorbed to create a carbonated water) or water from external supply (not necessarily carbonated and if the making of CaC03 in the electrolysis cells is not required, could be plain de mineralised, de carbonated water).

[0210] CAO=The flow of CaO (calcium oxide) added to the carbonated water flow feed into the electrolysis cells (or into the electrolysis cells electrolyte directly), to react during the energised electrolysis process, with the C02 absorbed in the water feed, to produce CaC03 and improve the efficiency of the electrolysis cell, by creating an enhanced ionic reaction. If CaCo3 is not to be made, then CaO need not be added and the electrolysis cell can be run with or without a salt added, It is preferred that the system is run using CaO as the feed water could/will be carrying carbonates, which without CaO or another salt choice will decrease the cell electrical efficiency and may damage one or both electrodes by deposits and build-ups.

[0211] EI=Electrical inputs to energise the electrolysis bank/cells/electrodes from renewables or on site generation.

[0212] ii) Details of optional CaS04 production system [0213] Key:

[0214] SL0=CaC03 slurry from electrolysis cells [0215] X=CaC03 store/processing [0216] CaC03=route for CaC03 product being dried [0217] CaC03B=CaCO3 slurry route to reaction vessel Y [0218] S02=Sulphur dioxide gas in feed to reaction vessel Y [0219] WS=Feed from post combustion products filter containing ash/char (modification as shown in drawings Figure 3)

[0220] Y=reaction vessel containing slurry composed of CaC03 and WS, through which S02 gas is bubbled through, chemical reaction CaC03+S02 — ->CaS04+C02

[0221] Y1 =outflow/store of CaS04 from reaction vessel y [0222] Y2=outflow/store of C02 from reaction of CaC03 with S02 [0223] Drawings Figure 8: Showing option to introduce and external source of C02 and or C02 / water vapour and/or any heat source containing vapours/gases/solids not detrimental to the equipment or processes or operation of the design. a. Component key [0224] Z= fuel source

[0225] D1= Methane supply, possibly dried and heated using recovered heat.

[0226] F1=oxygen supply (from water electrolysis bank component F not shown)

[0227] A=primary combustion chamber/section fed by fuel Z and/or combination of fuels and (if required Dried and heated Methane fuel supply D1), and heated oxygen supply F1 to provide heat energy for boilers or multiplicity of boilers to raise steam. (Or gas turbine or reciprocating engine to make electrical energy if fuel Z is suitable i.e. gaseous or liquid fuel) possibly at High internal pressures, and post combustion flue product flow G1.

[0228] AS=Supplemental or additional source of C02 and/or C02 and water vapour and/or any other source of C02 or heated material composed of solids, liquids or vapours that is not detrimental to the equipment or processes of the design, such as exhaust from a cement production kiln or rotary kiln.

[0229] AS1 =flow from AS [0230] ii)Component Key

[0231] A=Combustion component A or multiples thereof [0232] B=Combustion component B or multiples thereof.

[0233] G2=post combustion section B products flow [0234] C= Heat exchanger or multiplicity of heat exchangers to recover heat and/or integral flue turbine or multiplicity of integral flue turbines powered by the velocity/pressure of the direct flow of products G2 becoming outflow G3.

[0235] AS=Supplemental or additional source of C02 and/or C02 and water vapour and/or any other source of C02 or heated material composed of solids, liquids or vapours that is not detrimental to the equipment or processes of the design, such as exhaust from a cement production kiln or rotary kiln.

[0236] AS1 =flow from AS

[0237] Drawings Figure 9: Variations and modifications showing some suggested arrangements of components A, B, C and D in series and modes of operation, as well as combustion choices that can be used in series. It is assumed components other than atmosphere AT can be multiplicities thereof. Components A, B, ABST, BBST, AGST and BGST fuels can be combusted with oxygen rather than air drafting and products are contained within a continuous/connected flue. Steam or gas turbines are assumed to have a rotational output shaft to rotate electricity generators (or rotate a mechanical drive). Key [0238] A=component A, primary combustion [0239] B=component B, secondary combustion [0240] C=component C, heat recovery section [0241] D=component D, cooling section [0242] AT=release to atmosphere

[0243] ABST=component A primary combustion as Boiler and steam turbines

[0244] BBST=component B secondary combustion as Boiler and steam turbines [0245] AGST=component A primary combustion as gas Turbines

[0246] BGST=component B secondary combustion as gas Turbines

[0247] Component A where combustion takes place and post combustion flow transferring to component B, where secondary combustion takes place, the and post combustion flow to component C and then from component C the flow enters component D.

[0248] Component A where combustion takes place (secondary combustion is absent) the post combustion flow then going to component C and then from component C to enter component D.

[0249] Component A where combustion takes place and post combustion products flow transferring to component B, where secondary combustion takes place, the and post combustion flow to component C and then going from component C, the flow exits to the atmosphere AT.

[0250] Component A where combustion takes place (secondary combustion is absent) the post combustion flow then going to component C and then from component C, the flows exits to the atmosphere AT.

[0251] Component ABST is where combustion takes place in a boiler to raise steam the post combustion flow transferring to component BBST where secondary combustion takes place takes place in a boiler to raise steam the post combustion flow transferring to component C and then from component C to enter component D.

[0252] Component AGST where combustion takes place within a gas turbine, the post combustion flow products then transferring to component BGST where secondary combustion in a gas turbine takes place the post combustion flow transferring to component C and then from component C to enter component D.

[0253] Component AGST is where combustion takes place within a gas turbine, the post combustion flow transferring to component BBST where secondary combustion takes place takes place in a boiler to raise steam the post combustion flow transferring to component C and then from component C to enter component D. [0254] vi) Component AGST where combustion takes place within a gas turbine, the post combustion flow products then transferring to component C and from there to BGST component where secondary combustion takes place within a gas turbine, the post combustion products flow transferring to an additional component C and then entering component D.

[0255] Drawings Figure 10: Variations and modifications showing further arrangement of a traditional air drafted combustion unit and series connected oxygen/fuel combustion units, where the post combustion products are transferred to sequential combustion units in a contained flue.

[0256] Traditional air drafted single combustion system with the post combustion flue products passing through a particulates or chemical scrubber cleaning device, before exhausting to atmosphere.

[0257] Key:

[0258] AD=Air Drafting (oxygen for combustion is drawn as a mixed constituent of air)

[0259] Z=fuel supply, to combustion chamber COM [0260] CLH=post combustion cleaner/scrubber to remove ash/char or neutralise certain products /heat recovery.

[0261] E=Exhaust flow [0262] ATM=Atmosphere

[0263] ii)Series combustion units using oxygen and fuel combustion, where post combustion products are transferred to a subsequent combustion unit, the final combustion unit transferring its flow to a heat recovery component C and then to the cooling component D.

[0264] Key:

[0265] OX=oxygen gas supply (preferred as pre heated)

[0266] Z=Fuel supply [0267] COM1=1^st in series combustion unit [0268] COM2=2^nd in series combustion unit [0269] COM3=3^rd in series combustion unit [0270] C=Heat recovery component C [0271] D=Cooling component D [0272] iii) Series combustion units (showing a shorter inter component transfer design), using oxygen and fuel combustion, where post combustion products are transferred to a subsequent combustion unit, the final combustion unit transferring its flow to a heat recovery component C and then to the cooling component D.

[0273] Key:

[0274] OX=oxygen gas supply (preferred as pre heated)

[0275] Z=Fuel supply [0276] COM1=1st in series combustion unit [0277] COM2=2nd in series combustion unit

[0278] COM3=3rd in series combustion unit [0279] C=Heat recovery component C [0280] D=Cooling component D

[0281] Drawings Figure 11 : Variations and modifications showing other designs and arrangement of combustion units as a series combustion process, where primary combustion units are arranged to transfer there post combustion product flows, within a contained flue, into a larger secondary combustion unit. Steam or gas turbines (not shown in drawings) are assumed to have a rotational output shaft to rotate electricity generators (or rotate a mechanical drive). [0282] i)Arrangement of 5 GST units (could be more or less individual GST units) fuelled by fuel input Z and oxygen supply OX, combustion taking place in the primary units GST which are gas turbines, the post combustion flows of the [0283] GST units being contained within a flue and transfer into the secondary combustion unit BST, fed by fuel input Z and oxygen supply OX, where secondary combustion takes place in a boiler to raise steam, the post combustion product flow being conveyed within a flue to the heat recovery component C and then onto cooling component D.

[0284] Key:

[0285] Z=Fuel supply [0286] OX=oxygen supply

[0287] GST=combustion unit gas turbine [0288] BST=combustion unit boiler to raise steam [0289] C=Heat recovery component C [0290] D=Cooling component D [0291] C0 =Carbon dioxide output [0292] CH₄=Methane output

[0293] ii) Arrangement of 5 BST 1 units (could be more or less individual BST1 units) fuelled by fuel input Z and oxygen supply OX in the primary combustion units BST 1 which are boilers to raise steam for steam turbines, the post combustion flows of the BST 1 units transferring into secondary combustion unit BST2 which is fed by fuel Z and oxygen supply OX and is also a boiler to raise steam to power steam turbines. The post combustion flow of BST2 then transferring to the heat recovery component C and then transferring to become the feed for component D cooling component.

[0294] Key:

[0295] Z=Fuel supply [0296] OX=oxygen supply

[0297] BST1=primary combustion unit boiler to raise steam for steam turbine

[0298] BST2=secondary combustion unit boiler to raise steam for steam turbine

[0299] C=Heat recovery component C [0300] D=Cooling component D [0301] C0₂=Carbon dioxide output [0302] CH₄=Methane output

[0303] Drawings Figure 12: Variations and modifications to show a remote water electrolysis plant design to supply Hydrogen to feed a Sabatier reaction (or other use) some distance away and/or network, and to supply oxygen to a body of water (or other use) to oxygenate the said body of water. A further design to show a remote water electrolysis unit supplied with C0₂ and with an energy supply to run/operate a Sabatier unit and cooling process/further processing to make CH₄ to liquid or to feed gas to grid and to supply oxygen to a body of water (or other use) to oxygenate said body of water. [0304] Simple drawing of a remote water electrolysis unit that has feeds of electrical energy and water, to feed electrolysis cell that electrolyses water to make elemental gases oxygen 0 and hydrogen H₂, the

[0305] Oxygen taking a route to oxygenate a body of water (or other use) and the hydrogen being piped to supply a Sabatier process at a power station, hydrogen network or other use.

[0306] Key:

[0307] W=water supply (preferred demineralised)

[0308] EE1 =Electrical energy supply (preferred a renewable source)

[0309] H2=Hydrogen gas output [0310] 02=Oxygen gas output [0311] EL=water electrolysis unit

[0312] Schematic drawing showing a remote water electrolysis unit combined with a Sabatier process and cooling unit being able to optionally make CH to supply a gas grid or make liquefied CH₄ using a cryogenic freezing plant (or other method of CH₄ liquefication) and make solid C0₂ in a separate cryogenic plant or release C0₂ to atmosphere. C0₂ gas being fed by pipe from a power station combustion unit or other source. Gaseous C0₂ is fed from a source CFCP to a Sabatier process (powered by energy source EE2 which may be electrical preferred as renewable, but could also be heat from another source), where gaseous C0₂ is combined with gaseous H₂ (at temperature and pressure required) to produce CH₄, C0₂, H₂ and water vapour, the post Sabatier flow then going to a Dl section (a pre cooling section may added if required, not shown in drawing Figure 12), which is a vessel filled with water ice, the post Sabatier flow then coming into direct contact with the water ice, to condense out the water vapour into liquid which exits the Dl unit as flow WO. The cooled CH₄, C0₂ and H₂ gases then are separated where possible, either by route FF to a cryogenic freezing component CRYO where C0₂ is separated, gaseous C0₂ from the CRYO function being then either returned to the Sabatier reaction C0₂ input, or to C0₂ supply to AT atmosphere or to CF cryogenic process to make solid C0₂. H2 gas from the CRYO section if separated can also be returned to the Sabatier reaction via flow H₂. The CRYO component also making liquefied CH . Gases exiting the Dl section can also be routed to gas grid feed G (with suitable processing, not shown in drawings Figure 12). Hydrogen is made by from water electrolysis unit EL fed by electrical supply EE1 (preferred a renewable electrical source), which electrolyses water from water supply W (preferred demineralised water) to elemental Hydrogen and Oxygen gases, the Hydrogen being fed to the Sabatier reaction and the Oxygen being fed to oxygenate a body of water (or other use).

[0313] Key:

[0314] W1 =water supply (preferred demineralised) for making water ice [0315] EE1 =Electrical energy supply (preferred a renewable source)

[0316] H2=Hydrogen gas output [0317] 02=Oxygen gas output [0318] EL=water electrolysis unit

[0319] CFCP=carbon dioxide supply from remote source e.g. exhaust from power station.

[0320] SAB=Sabatier reaction chamber/heat exchanger [0321] EE2=energy source likely to be electrical, but may be heat or recovered heat from another process

[0322] WO=melt water output from Dl unit.

[0323] Dl=unit to bring post Sabatier products flow into direct contact with water ice introduced into the vessel (without affecting pressure integrities of the flow)

[0324] FF=post Sabatier products flow consisting of CH , H and C0₂ [0325] CRYO=Cryogenic processing plant to separate C0₂, then produce liquefied CH₄ and cool gaseous H₂

[0326] C0₂=carbon dioxide flows C0₂ as gas

[0327] G=lnput to the gas grid/network

[0328] CF=Separate cryogenic processing plant for C0₂

[0329] SC=Solid carbon dioxide to store

[0330] AT =Release of C0₂ to atmosphere

[0331] LCH=Liquefied methane CH₄ to store [0332] Drawings Figure 13: Modifications and variations. Cross section of two differing use suggested designs of the water ice cooling column/vessel found in unit Dl (in drawings Figure 6, Figure 12 and Figure 14) and DISP (drawings Figure 6), a section of the larger cooling component D. Water ice (preferably demineralised) is introduced into the top of the vessel from IM at a continuous rate sufficient to keep the vessel full of water ice I. The cooled gases (mostly C0₂) and water vapour as flow GF1 or GF2 enters the bottom of the vessel, the ice held by a perforated tray with the melt water collecting beneath as Ml (shaded area) and exiting the vessel as flow WO, the flow GF1 or GF2 passing up through the water ice column condensing out water and allowing C0₂ to be dissolved into water/water ice. Gases H₂ and CH₄ if present do not dissolve into water and can therefore pass through the water ice column without being dissolved, some or all (depending upon sizing and C0₂ present) of the C0₂ can be removed by this method although it is expected that large flows of post

[0333] Sabatier products would have flows containing amounts of C0₂ that could not all be absorbed, requiring removal of C0₂ by another method, prior e.g. to CH₄ liquefication.

[0334] Drawing of a cross section through a suggested vessel design for a post Sabatier products flow contact with water ice. The flow GF1 is thought to consist of water vapour and gases CH ,H₂ and C0₂, passes into the lower part of the vessel, and up through the water ice column, C0₂ being absorbed into the water and the CH₄ and H₂ passing up through the vessel to exit as flow C, to go onto further processes. The water vapour from the post Sabatier flow GF1 condensing out, with water ice I to produce the melt water Ml, which exits the vessel as cold water flow W01.

[0335] Key:

[0336] W water in feed, preferred demineralised [0337] EE1=electrical supply preferred a renewable source [0338] IM=Water Ice maker, crushed, flaked or shaped [0339] l=water Ice

[0340] GF1=Mixed gas/water vapour stream of CH , H₂0 vapour, H₂ and

C0₂ [0341] Ml/shaded area=liquid Water ice melt/condensed water vapour

[0342] W01 =outflow of cool liquid water from vessel

[0343] C=outflow of CH and H₂ gases with little C0₂ gas or none

[0344] Drawing of cross section through a suggested vessel design to cool a flow of mainly C0 and water vapour H₂0, by direct contact of product flow with water ice. The flow GF2 passes up through the ice column and over flows into a none water ice compartment, the water vapour being condensed out and the flow mostly being cooled C0₂ gas, exiting the chamber as flow COO. Melt water and condensed water vapour, falls to the bottom of the vessel as liquid Ml exiting the vessel as flow W02.

[0345] Key:

[0346] W water in feed, preferred demineralised [0347] EE1=electrical supply, preferred a renewable source [0348] IM=Water Ice maker, crushed, flaked or shaped [0349] l=water Ice

[0350] GF2= C0₂ gas/water vapour stream

[0351] Ml/shaded area=liquid Water ice melt/condensed water vapour [0352] W02=outflow of cool liquid water from vessel [0353] COO=overflow and outflow of C0₂ gas [0354] Drawings Figure 14: Modifications and variations [0355] Shows a suggested alternative design for a system of processing the post combustion flow into C0₂ gas and or to a cryogenic freezing process to make C0₂ (solid).The post combustion products flow, cooling section (or component D in drawings Figure 1) uses the similar aspects of the unit processes, as shown in drawings Figure 6, in that the post heat recovery section/and or post combustion products flow, (composed of hot gases and water vapour) is flow G3, entering unit DG1 which is a gas heat exchanger, the coolant in feed being flow GI1 and the coolant outflow as G01 , the coolant gases being either H₂,0₂,C0₂ or CH . The post combustion product flow through DG1 becoming flow G31 which enters a second gas heat exchanger DG2, with coolant inflow GI2 and coolant outflow G0₂, the coolant gases being either H₂,0₂, C0₂ or CH₄. The post DG2 unit flow becoming flow G32 entering the unit DW, which is a water cooled heat exchanger, fed by cool/chilled water inflow Wl and exiting as flow WO. The cooled post combustion products flow exiting DW becomes flow G33 entering into unit Dl which is a vessel capable of continuous filling of water ice as required, flow G33 being introduced at the bottom of the ice water column and coming into direct contact with the water ice, made by water input DMII, condensing out the water vapour as liquid water which exits the vessel as flow W02 (and can be used as inflow water coolant input Wl to DW unit), to leave a flow mostly of cooled C02 gas, which can either exit the unit Dl through the DICO route (which could be C02 gas to atmosphere), or exit the Dl unit as flow G34 going to the CRYO unit (fed by energy input EN1, which is preferred as renewable electricity, which could also be a heat exchanger to recover heat), where the cooled C02 is taken down to temperatures to make frozen C02 solid (suggested as -80oC,but other temperatures and pressure as required). It is assumed that heat produced when cooling can be recovered to use elsewhere e.g. to pre heat fuels. This cooling component design enables a combustion plant to manage C02 flows as part can go to atmosphere and part can be made into a solid that can be exported for use in other processes e.g. as a coolant.

[0356] Key:

[0357] G3=post combustion products flow entering DG1

[0358] DG1 =gas cooled heat exchanger

[0359] GI1=gas coolant inflow into DG1 suggested as H₂, 0₂, C0₂ or CH₄ gases

[0360] Introduction to drawings continued:

[0361] G01 =gas coolant outflow from DG1

[0362] G31=post DG1 product flow to DG2

[0363] DG2=gas cooled heat exchanger

[0364] GI2= gas coolant inflow into DG2 suggested as H₂, 0₂, C0₂ or CH₄ gases

[0365] G02=gas coolant outflow from DG2

[0366] G32=post DG2 product flow to DW

[0367] DW=water cooled heat exchanger [0368] W coolant water input to unit DW

[0369] WO=coolant water output of unit DW

[0370] G33=post DW product flow to Dl

[0371] D direct water ice cooling vessel

[0372] DMII=water inflow to Dl to make ice solid water

[0373] W02=liquid water outflow from Dl

[0374] DICO=outflow from Dl unit if required of cooled C02, if required to atmosphere

[0375] G34=post Dl unit flow, mostly of cooled C02 gas

[0376] CRYO=cryogenic freezing unit to make C02 gas to C02 solid

[0377] SC02=solid C02 output

[0378] EN1=energy input preferred as a renewable source, could also be a heat exchanger.

[0379] Drawings Figure 15: Modifications and variations [0380] Shows a suggested large volume oxygen supply device using atmospheric air intake from a tall column structure WP which has an internal cluster of reducing height pipe intakes, enabling air to be drawn in at segmented heights of the vertical column (rather than just one point) .having also an external weather cover which could be louvered or perforations. Atmospheric air ATM is draw by a fan located in the air filtration unit FT, which also filters the air from particulates and could also dry the air, powered by electrical supply EE1 which is suggested as renewable electricity supply. The air flow from the FT unit then goes to the air separator unit AS which (using either micro filter separation and/or pressure swing technology) separates the oxygen from the air to give supply/flow OG which is then put to store SSO, which has the outflow HX whereby the oxygen is pre heated for use in the combustion processes/units. The air separation unit AS also has an output flow NOG of the non-oxygen constituents of air (mostly Nitrogen) which can be sent for other processes e.g. ammonia manufacture.

[0381] Key

[0382] WP=tall column induction of air device, enabling air to be drawn in through a protective weather shield, to tubes of graduated height to draw atmosphere at various points of height (rather than one individual point) [0383] ATM=atmospheric air drawn into the device WP [0384] FT =filter of air drawn in, and fan or system to draw air [0385] EE1=electrical supply to supply unit FT (and air separation/oxygen supply system in whole) preferred as renewable electricity supply.

[0386] AS=air separation device, to separate oxygen from other constituent gases of air, suggested as micro filter or pressure swing technology, but could be other method such as cryogenic separation.

[0387] NOG=outflow from device AS mostly composed of non-oxygen constituents of air (mostly Nitrogen)

[0388] OG=oxygen gas flow from air separator unit AS [0389] SSO=store of gaseous or liquefied oxygen, preferred gaseous [0390] HX=outflow of oxygen store SSO, of oxygen gas to be pre heated for the combustion process

[0391] Drawing showing suggested dispersion unit for large volumes of C02 to be released to atmosphere, from processes such as combustion of fuels, or other processes. Flow FC is C02 gas to a store CC02, which may also have a fan to push the C02, powered by electrical supply EE1 preferred as renewable electrical source. The C02 gas flow COG then being forced by pressure to rise up the tall exhaust column (it could also be drawn up by air movement effects at the top of exhaust column e.g. the venturi effect), the C02 gas then overflowing from the top of the exhaust column, into a space/chamber which has a weather protection outer shield that may be louvered or perforated, to allow for the dispersion of flow COG to the atmosphere ATM. By dispersion of a heavy gas such as C02 to height in tall exhaust, that allows the gas to spread, in a more even dispersion should be achieved of at dense gas at volume.

[0392] Key

[0393] FC=supply of C02 gas (preferred with water/water vapour removed) [0394] CC02=store of C02 gas with possible fan to drive C02 in flow out of store CC02

[0395] EE1=electrical energy supply to drive system, preferred as a renewable supply. [0396] COG=flow of C02 from CC02 up through exhaust column to the dispersion chamber/space, to exit through perforations/louvres to atmosphere.

[0397] ATM=atmosphere.

Generalities and understanding

[0398] This system of generating electricity by oxygen fuel combustion in boilers to raise steam for steam turbines or gas turbines or reciprocating engines, where the rotational output power shafts rotate an electrical power generator (or combination of combustion units powering electrical generators) is fairly well developed, but there are inherent inefficiencies such plants leading to fuel energy values conversion to electrical energy values of 30% to 45%, which in turn means carbon dioxide (C02) emissions are unnecessarily created due to these inefficiencies.

[0399] The general principals and innovative steps used in this patent application combine to give greater electrical outputs per kg of fuel combusted than any power station in use. A simple description is that fuel is combusted with oxygen, negating the need to heat the 78% Nitrogen gas component of air present in traditional air drafting, and have to exhaust the nitrogen/nitrogen oxides gases and the heat that the exhaust gas carries. If you can heat the oxygen supply feed to the combustion using recovered heat you can reduce the fuel required further as you are inputting heat. Not all fuels can be pre heated, but both Hydrogen (H₂) and Methane (CH₄) gases have high auto ignition temperatures, meaning they can be pre heated to high temperatures with recovered heat allowing for heat to be inputted replace combustion/fuel needed. Combining both pre heated oxygen and pre heated fuel and not heating the nitrogen gas constituent of traditional air drafting feeds, gives an immediate thermal and fuel used efficiency, noting also that exhaust volumes are reduced and the related heat/stack losses. This fuel reduction can only be estimated as differing combustion systems exist, but 15% to 25% fuel reduction compared to air drafting combustion seems possible.

[0400] Another innovative step of this application (and previous related ones) is series combustion and conversion of C0₂ to CH₄ in a Sabatier reaction enabling C0₂ emissions to be converted into a fuel. The Sabatier reaction is a gas mixing heating and pressure reaction considered to be 80% efficient in reactants and products, but theoretically quite energy efficient in operation as low heat exchange/heat loss reaction system. C0 is a gas created from oxygen combining with carbon in a process such as combustion, however efficient combustion is not easy to achieve, and lower combustion temperatures using air drafting can give uncombusted and intermediate combustion products, that have to be extracted as ash or char. Series combustion units that connect the flue of the preceding combustion unit, allowing its combustion products to be introduced into the next combustion unit, to be oxygen combusted with fuel, is possible, enabling heat to be transferred that would normally be lost as exhaust to atmosphere (sometimes referred to as stack losses) and also offering the uncombusted and intermediate combustion products, to be heated and go through combustion again, a secondary oxygen combustion stage enabling more carbon to become C0₂.

[0401] A further innovative step in this application (and previous related ones) is that C0₂ is absorbed by water to produce carbonated water, also making use of the known properties of hydrogen and methane not being soluble in water enabling C0₂ to be removed or partially removed to make a carbonated water. This carbonated water is slightly acidic and when Calcium Oxide (CAO) is added (a salt of Calcium) creates an ionic reaction/solution, which when used as an electrolyte in an electrolysis cell, improves ion transfer and improves the efficiency of the electrolysis cell in being able to electrolyse water to elemental hydrogen and oxygen gases at the separate electrodes. When calcium oxide is added to the carbonated water and electrolysed, the calcium oxide becomes calcium carbonate precipitate/solid (CaC0₃) which will accumulate on one of the electrodes and will need to be removed from the electrode and electrolysis cell. Calcium carbonate as solid when removed from the electrolysis cell has two routes, the first being to dry it and return it to a Calcium oxide production process (a cement kiln for example) and it can be a renewable intermediate material in electrolysis of carbonated water, the second route also shown in this patent application is to use it as flue gas scrubber see drawings Figure 3, where an initial combustion stage produces ash/char, the slurry incorporating the particles and or have sulphur dioxide gas (S0₂) bubbled through the CaC0₃ slurry where a chemical reaction takes place to form Calcium Sulphate (CaS0₄) and C0₂ gas is made. CaS0₄ is a form of cement and a useful building product making for example flame resistant wall boards. There is physical property difference with CaS0₄ made from CaC0₃ from an electrolysis compared to using CaO from a high temperature cement kiln, in that the CaO from the cement kiln is composed of sintered particles which under the microscope have jagged exteriors, CaC0₃ formed in the electrolysis cell has particles which under the microscope appear more rounded and pebble like, this physical difference in particles suggests that CaC0₃ formed in the electrolysis cell may not suite some building applications when converted in CaS0₄, where the sintered particle enables better binding with some aggregates such as sand.

[0402] This patent application sees use in addition of CaO to an electrolyte of carbonated water, to aid the electrolysis efficiency and produce a useful building material, however it may be that a user of this design, does not wish to use CaO as electrolyte additive to make CaC03 (not shown in main drawings) and run the electrolysis cells in a different way. A different salt could be added that makes another use of the carbonated water electrolyte in a different way or the carbonated water produced by the cooling process of component D could be diverted to a different treatment process to precipitate out the C02 as chemical substance and the electrolysis cells run with a plain non-carbonated, low mineral content water electrolyte. It is felt that running an electrolysis cell with a high carbonated water electrolyte without the addition of CaO or suitable similar salt, would cause damage to the electrodes of the electrolysis cell and have detrimental economic efficiencies to the running of efficient electrolysis cells, but they can be run this way if required.

[0403] Water electrolysis, where the water is not saline or of high mineral content or is carbonated can be done and this patent application clarifies this for situations where a hydrogen (and/or oxygen) collection system is required from remote water electrolysis units to supply to the power station oxygen combustion and/or the hydrogen for the Sabatier reaction (see drawings Figure 12). These units do not operate with calcium oxide or other salt added, they are less efficient but where a renewable source of electricity is used to energise the electrolysis cell and water is available to be electrolysed, then such units could supply regular feeds of hydrogen and/or oxygen. A further option for the remote electrolysis units, is for the hydrogen to be piped to the power station/Sabatier reaction and for the oxygen to be bubbled (preferably at depth) into a body of water or ocean. Oxygenating water bodies could be useful in increasing their ability to produce food and deal with some pollutants. A further option (shown in modifications and variations drawings Figure 12 ii)) would allow for C0 to be piped to hydrogen collection stations and the Sabatier reaction and make CH conducted at separate sites, if an energy source is available for the process.

[0404] A further innovative step of this application (and ones related to it) is the use of temperature and pressure differentials of the process, after exiting the final combustion unit, the flue products flow enters component C which is a heat recovery section (see drawings Figure 5). As series connected combustion units are used, the flue products flow continuously and are not put to atmosphere as exhaust. The post combustion flue products flow into component C could contain mostly C0₂ and water vapour H₂0, the water vapour carrying considerable heat energy enabling a very powerful heat recovery section, which can then and/or power a further steam boiler to power steam turbines and electrical generators, or air/turbine or gas turbine to power electrical generators or reciprocating engine to power electrical generators, or be used to pre heat oxygen and fuels prior to combustion uses in components A or B. It is possible the post combustion flue products entering into component C could be at high pressures giving a flow of velocity, which in its self could power simple turbines utilising the pressure and velocity of the flow to give a rotational output shaft, to power electrical generators, however component C is connected to the cooling component D, as the post combustion flue products flow through the component D, they reach a temperature in the Dl section (see drawings Figure 6) of less than 10°C. Given the large volume of hot gases and water vapour entering into component C and the connection to the low 10°C or less, and low volume of the gases and water vapour in component D, Dl section, there is a considerable temperature/pressure gradient which can be taken of advantage of in providing possible quite high velocities of moving, post combustion flue product flows in component C sufficient to power simple flow integral turbines (single rotor similar to wind turbine), with a single rotor and mechanical power linkage to the outside of the flue products containment wall (not affecting the containment integrity), to power an electrical generator, and/or more complex turbines of multiple rotors on a single rotational power transfer shaft that passes through the flue products containment wall (not affecting the containment integrity) to power electrical generators, or possibly something similar to steam turbine or gas turbine arrangement, with a rotational output shaft powering a generator or multiplicity thereof. Current electricity design power stations do not make use of this as they have no requirement to attach a post combustion flue products flow to a cooling system that could make remove water vapour and be connected to a Sabatier reaction to process the cooled remaining C0 , into CH . It can be shown therefore that the electricity generation power station, from the series combustion of fuels with oxygen and the cooling of the post combustion products, has the facility to power additional electrical generators, not available on current designs and give a greater electrical output per Kg of fuel combusted, than current designs.

Process flow

[0405] Fuels for the primary combustion component A (or multiplicities of component A) ideally is biomass or, Bio solids however any combustable fuel (and where allowed pre heated from recovered heat) can be used, depending upon what is required, the fuel is combusted stiochmetrically (with the required amount of pre heated oxygen gas and not traditional air drafting) thought to be more efficient where the combustion is used to heats boilers, to raise steam to power steam turbines to power electrical generators. If gas turbines are used in component A then solid fuels (or fuels with solids) cannot be used as turbines work on gas expansion from combustion, to give pressure onto shaped turbine blades causing rotation, and heat is often although not always recovered. Gas turbines have advantages in speed of bringing into operation and closing down and can be less complex and less costly than boilers and steam turbines in combusting gases and liquids. Reciprocating engines as component A require a liquid or gaseous fuel, and both gas turbines and reciprocating engines with oxygen combustion will give an exhaust mostly composed of C02 and H20, with little ash or char. [0406] The post combustion products of component A are contained within a flue or pipe (as flow G1 ) that transfer them to the secondary combustion section of component B, where a fuel and pre heated oxygen (preferred as pre heated methane but could also be other fuels or pre heated fuels) are combusted stiochmetrically and not using air drafting, creating heat used to heat boilers, to raise steam to power steam turbines to power electrical generators. If gas turbines are used to power electrical generators in component B then solid fuels (or fuels with solids) cannot be used. Reciprocating engines used to power electrical generators in component B require a liquid or gaseous fuel, and both gas turbines and reciprocating engines with oxygen combustion will give an exhaust mostly composed of C02 and H20,with little ash or char.

[0407] The post combustion products of component B (or multiples of B in series or parallel arrangements) are contained within a flue or pipe (as flow G2) and transferred to component C (or multiples of component C in series or parallel arrangements), which is a main heat recovery section and additional electrical power generation. The series combustion, transferring combustion products to the next combustion section enables, heat normally lost to exhaust to be transferred and allow for lower fuel use, if there are multiple stages of connected combustion, then post the final stage, considerable quantities of gases and water vapour could be present, the water vapour in particular could be carrying a great deal of heat as water has a high enthalpy value, and removing some of this heat in a heat exchanger, aids the subsequent performance of the cooling section component D. The heat exchanger (or multiple heat exchangers) should take heat from the flue products flow passing through component C, the heat can be used to pre heat fuels and/or oxygen used in the combustion components A and B, and/or provide a source of heat to a boiler to raise steam to power a steam turbine to power an electrical generator (or multiples thereof), or could heat air/gas to power a turbine (similar to gas turbine) to power an electrical generator (or multiples thereof).

[0408] The flue products flow of component C could be under pressure within component C at temperatures of over 100°C,the connection to the cooling section component D is a gradient of pressure, component D causing gas and vapour reduction in volume compared to those entering component C .This pressure gradient can be utilised, in that a continuous velocity is created, which can be engineered to give suitable pressures to power simple single rotor turbines or multiple rotor turbines (more resembling a steam or gas turbine rotor arrangement), that have rotational power output shafts to the external of the flue containment (without degrading the flue containment functions) that can rotate/power the shaft of electrical generator (or multiples thereof).

[0409] The flue products flow from component C then enters component D (as flow G3 see drawings Figure 6) is the cooled post combustion products flow (from component B or component A if B is absent) and should be composed of mostly C02 and H20. Component D should be powered by renewable energy sources where possible, but can use energy made on site. It is understood that some sections of component D can be reduced or increased or removed as per operational requirements, e.g. a plant design that only requires water cooling rather than gas cooling sections.

[0410] The purpose of component D (or multiples thereof) is to not only cool the post combustion flue products flow but to heat gases used as coolants, to either temperatures suitable for supplying the gas grid network or for the higher temperatures of pre heating fuel and/or oxygen to feed components A or B, it is both a cooling system and heat recovery system. Component D has two cycles of cooling which could be made to operate continuously (or separately for better process management, if stores are incorporated, not shown in drawings). The first cycle takes the output flow from component C and has two stages of gas cooling in DG1 and DG2, then a stage of water cooling DW and then introduction to an water ice column section, Dl where water ice either crushed, flaked or cube ice is introduced into the top of the vessel (in a way that does not affect the containment of the flow within the vessel), where the water vapour should condense out to be removed from the vessel (as flow W02) and can be used as a coolant (as flow Wl, in the DW water cooling unit) before being fed to the water electrolysis bank, or other process or treatment. The DICO flow of the Dl section is a controllable cool C0₂ gas flow, enabling C0₂ to be drawn off where balances of C0₂ are required to be removed as it cannot be processed in the Sabatier process, for example because hydrogen is limited or the Sabatier process is unavailable. This C02 from the DICO flow of the Dl unit can be itself cryogenically treated (separate unit not shown in drawings), to produce solid C0₂, or stored or released to atmosphere, it could be a regular operation or one only used in emergency situations.

[0411] This should then leave a flow of cooled C0₂ gas. The C0₂ gas is then mixed with hydrogen in Sabatier reaction vessel SAB at a ratio of 1 volume of C0₂ to 4 volumes of hydrogen (and or mixing volumes as required) and taken up to temperature and pressure thought to be around 300-400°C and 50psi 345 kilopascals (or whatever temperature and pressure combination is required), forming Methane in the following chemical formulae C0₂+4H₂ - - CH₄ +2H₂0, and also water as vapour. Post the Sabatier reaction pressure should be maintained to below 200°C (or what temperature/pressure combination is required to stop the reaction of CH₄ reforming back to C0₂) whilst cooling the flow. This could be achieved using a heat exchanger device where outgoing products post Sabatier reaction, heat incoming C0₂ and hydrogen gases, helping to give thermal efficiencies .Heat energy may be required in the Sabatier reaction, a renewable source of energy is useful for this as is a renewable source providing energy for component D. The second cycle is to process the post Sabatier products of gaseous CH₄ and unreacted C0₂ and H2 and water vapour, which again passes through two gas cooling stages DGPS1 and DGPS2 and a water cooling unit DWPS2 and a final direct contact with water ice in DIPS2 where water ice either crushed, flaked or cube ice is introduced into the top of the vessel, in a way that does not affect the containment of the flow within the vessel, (the outflow of which W02PS can be used as water coolant inflow WIPS for section DWPS2) which may be capable of removing all of the C0₂ by absorbing the C0₂ into the water/ice, before flowing on to the Cryogenic freezing /cooling unit CRYO, any remaining C0₂ should be removed first from the post DIPS2 flow, leaving only H₂ and CH gases to be reduced to very low temperatures (or process temperatures and method as required) to liquefy the CH gas, which is thought to be around - 160°C. This temperature whilst very low is not sufficient to cause H₂ gas to liquefy which should remain as gas. Other methods of lowering pressure are used in creating liquefied CH and if suitable these may be used, molecular filters can be used to remove C0₂ and separate mixed gas streams if this is suitable for the process. The products from the CRYO section of liquefied CH₄ (and or solid/liquid C0₂) then going to store, the cooled H₂ gas can be used as electrical generator coolant, and or can be returned to be used as the H₂ feed for the Sabatier reaction, enabling some economy in H₂ usage. The heat extracted from the CRYO section process may be substantial and can be used as recovered heat to pre heat oxygen or fuels in the combustion components A or B or elsewhere.

[0412] Liquefied CH₄ gas from the store (or Natural gas or Methane or Bio gas from external sources) can be used in combustion components A and B and pre heated by becoming coolant feeds in the gas cooling heat exchanger sections of component D .The liquefied CH can be used from store as it is, to fuel for example transport vehicles, or if requiring to return the liquefied CH₄ gas to input in gas grid network, can again be used as a coolant feed in the gas cooling heat exchanger sections of component D.

[0413] This concludes the description of the basic and innovative steps of the patent application; further description follows to explain the important modalities of operation and the larger energy system making use of the innovative steps defined in the application are in the expanded modifications and variations.

Modality and system features description

[0414] An alternative, external source of C0₂ (and/or other heat source of substances that are not harmful to the processes and equipment of the system) can be introduced (see drawings Figure 8 i) and ii)) e.g. the exhaust from a cement kiln or rotary kiln. This can be introduced at any point prior to the flow from component B to C (combustion to heat recovery), the drawings suggesting, it is introduced between component A and component B and or B to C, the effects would be different, if introducing between component A to B (or pre to A combustion) if a hot source of C0₂ this may act to reduce the fuel requiring to be combusted in B components, if introducing the external source of C0₂ from B to C, it would enable greater heat recovery, however in both examples the C0₂ in the system may be increased and therefore CH outputs from the cooling and cryogenic separation component D, as well as other parameters changing. This external C0₂ source should be consistent as it will affect the running of the system and ideally be hot or heated, as a cool or cold source of C0₂ will cause more fuel to be combusted in the system to gain temperatures, cold or cool external C02 feed could however work in a gas turbine arrangement where gaseous expansion plays a greater role in determining power outputs.

[0415] The pre heating of fuel and oxygen feeds is envisaged to utilise as much recovered heat as possible, from combustion/heat recovery sections, coolant sections, water ice making and cryogenic sections. It is expected that 200°C is a reasonable temperature to pre heat fuels and oxygen to and gives good thermal efficiency; however 400°C and higher where safe to do gives improved thermal efficiency. A modality could be that some combustion processes have fuel and/or oxygen heated to different temperatures e.g. higher temperatures for a biomass or tyre crumb combustion section oxygen/and or gas fuel feed to assist combustion.

[0416] Where water supplies may be a problem fuels such as alcohol offer a great production of water from combustion, and oxygen combustion does offer the opportunity to use free water/higher moisture content fuels such as bio solids, at the time of writing it is unknown what the maximum free moisture content, of fuels could be considered, and is thought to be around 30%, the free water being of use in thermal performance of the series combustion A and B components and component C heat recovery sections due to its enthalpy value, as well as providing water for the electrolysis bank and/or for steam circuits use. It is possible that in some modes of operation that an excess of water could be produced, giving this system the potential to provide a source of water for example to use in irrigation or agriculture, some configurations may require that water may have to be drawn /consumed rather than in the balances from combustion derived water. The high temperatures of oxygen combustion and co firing of fuels stiochmetrically (with Oxygen) bringing into range of use previously difficult combustion fuels that gave emission problems due to low temperature combustion, and may offer a route for number of previously more difficult fuels to combust such as tyre crumb or powder.

[0417] The water electrolysis bank F, splits the water molecule into its component elemental gases of Hydrogen and Oxygen (which if in excess can be diverted for other uses/processes shown in drawings Figure 8), electrolysis cell efficiency can be improved by adding a salt to the electrolyte, as water can absorb C0 , this can be used, by adding to this C0₂ saturated water, Calcium oxide which in the electrolysis cell creates Calcium Carbonate as a solid deposited on one of the electrodes, which can be removed from the electrolysis cell as a solid, and further processed as slurry through which S02 (and/or other products/substances) can be bubbled through to create CaS04 or Calcium Sulphate solids which is form of cement and used in the building industry . The outputs of this material may not be high, but may well offer a small economic benefit in making a by-product that can be used. If the water electrolysis bank F does not want to use a salt in electrolysis, it can still operate, so the use of CaO is a choice to make use of the C02 saturated water and a small improvement in water electrolysis cell efficiency, and ability to run in the absence of CaO. It is however preferred to operate the electrolysis cell using a suitable salt and CaO is a good and plentiful choice to improve the electrolysis cell efficiency and remove carbonates from the electrolyte undergoing electrolysis, to give some renewal of the electrolyte by incoming fresh electrolyte with a salt preferred as CaO. The system in this patent application (and others related to it) offers modality and flexibility of operation and design possibility to give further fuel efficiencies, variations in electrical output and production of CH from the Sabatier reaction which may help with demand patterns and seasonal variations which in the UK are quite marked, mid-winter using double the amount of electricity than in midsummer, so in a UK summer a system of these energy plants can be run to lower electrical outputs and burning of fuel or some shut down completely, in a UK winter the plants can be run to full electrical output and fuel use, which nuclear and conventional combustion technology designed plants are unable to do.

[0418] By being able to remove C0₂ as a gas (see drawings Figure 6 DICO flow) enables, C0₂ to be balanced, should hydrogen for the Sabatier reaction be unavailable or other problem/requirement of the process. As the C0₂ being processed in a large electrical power generation plant could be considerable, it is thought that tempory storage would quickly become impractical and release to atmosphere may be the only option. A further modality is to use the flow G4CF (see drawings Figure 6) and use the mixed gas stream with the water condensed out, as a gas coolant and then and/or as a fuel/co firing the combustion sections components A and B. This would save energy on removing the C02 gas and subsequent cryogenic cooling to make liquid methane and super cool hydrogen gas, and gives further flexibility of the energy plant as a whole unit.

Modifications and variations

[0419] Additional component B secondary combustion sections can be added in series or in parallel to increase electrical outputs and optimise the efficiency of secondary combustion and hot oxygen and Methane feeds to the combustion, creating a high efficiency, high electrical output system. Secondary combustion units may also allow for particles from component A that were incompletely combusted to be combusted again more completely, in some cases removing the need for any pre component B ash or char separation. Making this patent application a low ash/char combustion system.

[0420] The making of CaC0₃ in the water electrolysis cells/bank is an option and need not be done, removing the energy requirement of making the CaO, however it is felt that electrolysing carbonated water without a salt may damage one or more cell electrodes. It is also possible that carbonated water produced by component D be treated in different way, and that water for the water electrolysis units be from a source that is not carbonated, and CaO need not be used/added to the electrolyte of non-carbonated water.

[0421] Turbines utilising the pressure and velocity of post combustion product flows can be utilised to power electricity generators to give additional electrical power outputs at other points in the system other than in component C, for example in post combustion flows between component A or B.

[0422] Gas turbines or reciprocating engines powering electricity generators can be used in place of boilers powering steam turbines that power electrical generators in components A or B; however it is felt that boilers, raising steam to power steam turbines to power electrical generators, will offer greater efficiencies, in continuous operation.

[0423] Alcohol or other fuel can be used in the secondary combustion component B; however it is felt that Methane will offer a better efficiency as Methane is also being made in the Sabatier process and this can be returned to be used as fuel.

[0424] Secondary combustion component B can be removed to have a simplified single combustion system and connected flue products flow, component A, and then to heat recovery component C and then to component D containing the Sabatier process and cryogenic separation.

[0425] By using multiple, component A and B combustion sections and components C and D, some flexibility can be designed into operation of the plant as a whole, to enable larger or reduced electrical power generation outputs to be controlled. These plants are designed to run at high outputs for long time periods, as they are series combustion and cooling systems, they cannot be turned off and on in short time periods (unless designed as small fuel input/small electrical output systems), by arranging the combustion components A and B to come in and out of use, e.g. from component A the flow G1 is split into flows to feed units of component B, similar to a manifold, flow G1 being sent to e.g. four component B units when high electrical loads are required, and flow G1 being sent to only 2 component B units when low electrical outputs are needed, enabling the plant to have some adjustments to what may be seasonal variations of electricity demand e.g. more electrical lighting being on during months of less sunlight. Suggested combinations of components A, B, C and D are difficult to define as they are details of engineering, however having two component A units feeding separate component B units as separate lines enables one line to be operational in low electrical demand and both lines in operation when electrical demand is higher. Placing component A and sequential series component B units will be limited by the engineered design as the outflow of post combustion products from the final component B, could be considerable in the order of 10s of thousands M3 per hour and subsequent heat recovery component C and cooling component D have to be designed to process the final combustion products stream, and it may be that the post combustion B component, flue products streams, require multiple component C and component D lines, this patent application is unable to show these possibilities of engineering requirement and constraint, but conveys that arrangements of the components A,B,C and D can be used to meet requirements of low or high electricity generation and/or some adjustment for the production of CH to liquid and store.

[0426] By having sections for post combustion product flows in section C, heat recovery sections/turbine electricity generators can be closed or opened to match, post combustion product flows, giving system flexibility.

[0427] The use of gas cooling heat exchangers, in component D to cool post combustion product flows, heats the gases used for cooling and can work as heat recovery to pre heat gaseous fuel or Oxygen, expanding these gases. The pressure of these cooling gas flows (or of the pre heated fuel gases or oxygen flows from component C) could be used to power smaller turbines that may generate electricity or turbines with mechanical outputs or have another use such as powering pumping water (not shown in drawings).

[0428] Hot Methane and Oxygen feeds to combustion units can increase thermal efficiency and reduce fuel use compared to systems that do not pre heat fuel or oxygen, by introducing heat into the combustion components. As air drafting is not used it is possible to pressurise some combustion sections which would require injecting pre heated fuels and pre heated oxygen, which may be possible in combustion components A and B. In component B that is also receiving a post combustion flow of component A (flow G1), this post combustion flow of component A would also have to be pressurised and introduced into the combustion chamber, systems where a gaseous or liquid fuel is used, it is relatively straight forward to design as engineering.

[0429] An additional source of C0 (see drawings Figure 8) from an external source such as the exhaust from a cement making kiln or rotary kiln, can be introduced to the post A combustion unit flow or post B combustion unit flow, (or pre A combustion feeds not shown in drawings Figure 8). The C0₂ enabling potential CH₄ production to increase from the Sabatier process and add some thermal efficiency/input to boilers (of component A or B) to raise steam or to recover heat (in component C) and assist in controlling oxygen combustion temperatures where said fuels used may generate very high temperatures when combusted such as alcohol or CH₄.This would also enable C0₂ to be reduced emissions from the cement plant, by converting them to CH₄ noting that cement production emissions are thought to account for nearly 10% of all global C0 emissions.

[0430] That this device is primarily for large electrical output generation and making CH₄ as an energy source/fuel to use and store, but could be of a size as to power ships efficiently and if safe could power smaller uses such as road transport or stationary engines. Rotational power output shafts that would power electrical generators in the patent application could be used to power mechanical drives, such as rope, chain, belt, pulley or hydraulic to rotate machines or gearbox inputs or propulsion devices such as a ships propeller or railway locomotive wheel.

[0431] That a reciprocating engine or rotary wankel engine such as an internal combustion piston/rotor engine (or multiplicity thereof) could be substituted instead of a combustion unit or boiler its best location being component A of drawings Figure 1. Using oxygen/fuel combustion could enable a piston reciprocating, or rotary wankel engine to be used as a secondary combustion unit, however there may be some difficulties in this and such secondary sequential piston reciprocating, or rotary wankel engines would require to make combustion in a mixed (post combustion products) gaseous flow as cylinder inlet. Sizing of the engines would increase with each sequential combustion unit and it is felt that such a system could not produce the high electrical outputs of a boiler to raise steam, to drive steam turbines, to power electrical generators.

[0432] The gas turbine as single stage gas turbine or two stage gas turbine does offer some use in the system of this patent application, as it use oxygen /fuel combustion, however generally speaking gas turbines run efficiently and safely, on gaseous or liquid fuels and if a gas turbine is used as component A combustion unit, the heat/post combustion flow, being transferred would become the intake of the

[0433] next gas turbine, such gas turbines usually preferring cool air/gases as intake as they are more dense when compressed, which poses a few problems at the intake design aspect of gas turbines being used as a secondary combustion system, there is also the problem of hard particulates of ash/char of incomplete combustion, or other substances from a post combustion unit damaging turbine blades, causing mechanical failure or impairment. The actual combustion within the single stage or two stage gas turbine is not a problem, pre heated fuel and oxygen combusted at high pressure could certainly, power the gas turbine very well, but gas turbines as used in most applications including aircraft propulsion, can develop high temperature exit flows or thrust, which could be difficult to transfer to a subsequent intake of a sequential combustion unit, giving difficult heat loads. It may be possible to arrange gas turbines in a semi-circle (as component A) and collect there exhausts to heat a boiler/heat exchanger (as component B) to raise steam to power steam turbines to power electrical generators (see drawings Figure 11 ).

[0434] That excess oxygen and/or hydrogen from the water electrolysis can be diverted and used for other processes if appropriate.

[0435] Internal flue/pipe restriction devices (e.g. a mechanical iris) to restrict post combustion flows and other flows in A, B, C and D (not shown in drawings) may help to manage pressures and velocities of materials to enable plant operational efficiencies.

[0436] The system of combustion of oxygen/fuel and use of the Sabatier reaction to convert C0 to CH₄, is designed to not emit/or emit low amounts of C0 (and also Nitrogen oxides as air drafting is not used). To achieve this hydrogen and oxygen gases need to be in plentiful supply when the combustion and Sabatier reactions are in operation. 1kg of water electrolysed should create 800g of oxygen and 200g of hydrogen and current data suggests 44kw of electricity would be required in current design electrolysis cells. In certain sizes of electrical output and if burning a high carbon content fuel this may create imbalances in the hydrogen and oxygen use rates, and in this application (drawings Figure 1 ) it is suggested that a device SSO for separating oxygen from air is used as an oxygen supply/store, and a hydrogen store SSH that can accept external hydrogen supplies (whether from electrolysis or another process) to supplement whatever oxygen and hydrogen supplies are being gained from on site or remote water electrolysis product sites. If possible the products in SSO and SSH stores should be powered by renewable electricity. Where oxygen and hydrogen gases are difficult to produce and/or balance, this patent application explains, that C0₂ could be released from the cooling component D from the Dl section (see drawings Figure 6) using the DICO outflow thereby reducing the amount of C0₂ processed through the Sabatier reaction to make CH . This cooled gas, mostly C0₂, can go onto further cryogenic processing to make solid C0₂ (or liquid is possible), which could have uses for cooling processes or use in market garden greenhouses in the growing season to provide/enrich the C0₂ atmosphere to increase photosynthesis, or other use, or be released to atmosphere on site as a gas via an exhaust.

[0437] From modification and variation item 17, it is also possible that a system of cooling, cryogenic freezing could be used that does not use a Sabatier reaction, but makes solid C0₂ (liquid C0₂ is also possible) from the flow in component D, post Dl section (see drawings Figure 14) a cryogenic section becoming the final stage after the Dl section, and the Sabatier and subsequent cooling processes removed. The quantities of solid C0₂ produced could be considerable and would need a use and transport. Not requiring a Sabatier reaction means that hydrogen is not required, thereby the system described in this patent application, would be oxygen series combustion, with oxygen separated from air or remote electrolysis sites/other sources (see drawings Figure 1 unit SSO and drawings Figure 15i), as no CH₄ is being synthesised on site, all fuel Z feeds of combustion components A and B would be fed from external sources and not utilise the methane synthesised on site. It is assumed that heat recovered would still be used to pre heat oxygen and gaseous fuels to gain the combustion efficiencies and efficiencies of a series combustion system with pre heated fuels and oxygen. An air drafted system of the design using the efficiencies of series combustion in this application is possible, but control over combustion would be lost, which is important in difficult fuels to combust such as tyre waste, as well as the major combustion efficiency of not heating the none oxygen constituents of air, it would also be as polluting as current power station designs in use at the time of writing.

[0438] Remote water electrolysis sites using renewable electricity (or supplied with excess electricity when available) need not supply oxygen via pipe to the combustion/electricity generation plant (see drawings Figure 12 i)) and could instead send the oxygen gas to be bubbled into a river or body of water such as an ocean (preferably at depth), the oxygenated water being able to sustain more life than low oxygen content water and help to deal with some organic pollutants. Hydrogen could be piped to the combustion/electricity generation plant, also saving on the pipe network cost required.

[0439] Remote water electrolysis sites using renewable electricity (or supplied with excess electricity when available) need not supply oxygen via pipe to the combustion/electricity generation plant (see drawings Figure 12 ii)) but could be fed by C0₂ piped in from a C0₂ production site e.g. combustion power station, being combined with H2 gas produced by the water electrolysis unit, in a Sabatier reaction, powered by the remote site renewable electricity (or supplied with excess electricity when available), the CH₄, H₂ and C0₂ going through a simplified cooling device to be further processed, to make liquefied CH or to be processed for release to the gas grid.

[0440] Drawings Figure 6 show units or stages of an efficient cooling system to help with the thermal energy balances and losses in processing post combustion product flows, potentially of considerable volume and heat content, water can be recovered, some C0₂ absorbed into water to make carbonated water which can be used as an electrolyte in the water electrolysis process and can also enable post Sabatier process gases to be separated to produce a cooled flow for Cryogenic liquefication of CH₄ gas. These units can be rearranged, removed or repeated/additional to give a different performance dependent upon the engineering required. The basic function of the patent application (and previous relevant applications) process and products keeping integrity, these being cooling of the post combustion product flows to condense and extract water vapour produced in combustion, to remove any ash and char and provide a concentrated flow of C0₂ for use in the Sabatier reaction, to cool the post Sabatier reaction products to condense and extract water vapour, and remove any or all unreacted C0₂ in the post Sabatier product flow and then process the CH and unreacted H₂ via a process that creates liquefied CH and H₂ as a gas suggested in the patent application as cryogenic freezing system labelled as CRYO (noting some systems lower temperatures to liquefy gases with a series of pressure changes or powerful magnets, which this application could also use).

[0441] The drying of gases may be required in some flows (not shown in drawings).

[0442] There is speculation in energy thinking of taking C0 gas produced from fuel combustion power stations and pumping it into underground rock strata or spent natural gas wells. This design in the patent application can produce large quantities of C0₂ gas, however there are problems with the procedure of underground sequestration of C0₂ in that eventually the rock strata or spent gas well will become full, and that all small experimental systems pumping C0₂ to rock strata store have underestimated the energy required to pump at pressure and typically 15% more fuel has to be burnt to do this, and it is not a variation the patent application inventor thinks is/or can be suitable.

[0443] A post Sabatier products flow (as in drawings Figure 6 flow G4CF) consisting of cooled gases C0₂, CH₄ and H₂ can be used as fuel/co firing in the combustion sections components A and B.

Advantages

[0444] High amounts of electrical energy production are possible as well as improved Kw of electrical energy per Kg of fuel as additional sources of electrical generation are possible.

[0445] Carbon dioxide from combustion can be converted into Methane via the Sabatier process, creating a low or zero C0₂ emission fuel combustion electrical energy generation system.

[0446] Current thermal and energy efficiency of current technology combustion electricity production power plants can be greatly improved, as thermal energy losses of traditional power station designs, can be recovered and used to pre heat fuels and oxygen efficiently, to be reintroduced as heat directly into the combustion units enabling fuel use to be reduced.

[0447] Biomass fuels can be combusted in these plants as well as fuels previous unused that only combust cleanly in the high combustion temperatures of oxygen fuel combustion, such as tyre waste or oil sludge’s. [0448] The higher energy efficiency means less fuel needs to be combusted enabling limited resource fuels such as Biomass fuels and recycled fuels to be more widely used.

[0449] By using the post combustion products flow from the primary combustion component A to heat a secondary combustion component B, large amounts of heat energy can be transferred/used to reduce the fuel consumption of the secondary combustion component B or multiples thereof.

[0450] By direct transfer of post combustion products flow from the primary combustion component A, to a secondary combustion unit B (or multiples thereof) if combusting a solid fuel or problem fuel that creates ash and char and/or incomplete combustion particulates, secondary combustion can combust these particulates further to create a low or zero ash/char combustion system and a final post all combustion units flow, mostly composed of C0 and water vapour. The flame temperature of an oxygen and methane combustion unit could be 2000°C or higher, giving very high combustion temperatures.

[0451] Dissolved C0₂ in water from the process used by the water electrolysis bank can be made into CaC0₃, by adding CaO to make a salt electrolyte that can improve electrolysis cell efficiency. Further processing of the

[0452] CaC0₃ by bubbling sulphur dioxide through the CaC0₃ slurry can produce a building material form of cement CaS0 .

[0453] Methane gas can be synthesised from C0₂ making electricity power generation by combustion of biomass /bio solids/waste rubber latex fuels with oxygen, low or zero C0₂, and providing methane source not from fossil fuel production systems directly.

[0454] Using biomass fuels can help to reduce the atmospheric C0₂ by utilising plant photosynthesis to use atmospheric C0₂ and store Carbon as plant sugars and structures and release 0₂.

[0455] Oxygen combustion offers more efficiency than using air to supply the oxygen for combustion as the other components of air do not have to be heated nitrogen gas comprising 78% of air, and this reduces Nitrogen oxide emissions. [0456] Oxygen combustion means higher combustion temperatures can be attained, bringing previously difficult fuels into use such as low grade biomass of paper and cardboard, tyre crumb and can use higher moisture fuels. The higher temperatures also help with emissions from the combustion of oils and fats and other complex combustion substances/molecules.

[0457] Hot Methane and Oxygen feeds to combustion centres can increase thermal efficiency and reduce fuel use compared to systems that do not pre heat fuel or oxygen and/or use current/traditional design air drafting.

[0458] In remote satellite water electrolysis units or where stores have an excess of Oxygen gas, the excess of Oxygen gas can be used to oxygenate rivers or oceans by supplying via a pipe, a bubble dispersion unit and Increase river and marine life and deal with problem organic pollution compounds present in the water, or the excess oxygen could be collected and used to power more efficient internal combustion engines or small boilers or some other use.

[0459] External C0₂ and C0₂/water vapour sources from other processes can be used to help with the thermal and fuel efficiencies of the design as well as increase CH₄ outputs e.g. the exhaust from a cement kiln or rotary cement kiln.

[0460] Excess Oxygen and Hydrogen from the electrolysis bank/system (and/or other parts of the system) can be diverted from the system flows to be used in external processes or equipment.

[0461] Early calculations suggest 10000kg per hour of biomass at heating value of 16000 KJ/KG could generate 600MW per hour of electrical energy where the C0₂ is converted into CH₄ and combusted in a series combustion system as described in this patent application, more than double current combustion power station outputs.

[0462] Though designed as a power station to make CH₄ and electrical energy, by replacing reciprocating engine, steam and gas turbine shaft outputs with mechanical drives such as chain, pulley or rope, mechanical outputs such as a ships propeller, can also take advantage of this system of improved combustion efficiency.

[0463] As a device smaller than a large power station this patent application design could make a fuel efficient type of engine for some transport or other functions requiring mechanical power such as milling of foods or rock crushing sorting.

[0464] In certain configurations of modality e.g. using a high moisture content fuel such as bio solids, it is possible that the system produces an excess of water, which may be used to irrigate agriculture or if processed as potable water.

[0465] There is a large temperature gradient between the final post combustion stage flue products flow and the cooling component section Dl (see drawings Figure 6) and the further cryogenic cooling section which produces liquefied CH₄ (thought to be at -160°C) .As the post combustion products flow is continuously cooled it reduces in volume, creating a pressure difference and velocity, which can be used to power simple or complex turbines with a rotational power output shaft to rotate a generator to make additional electrical power.

[0466] (In drawings Figure 1 key S1 and S2 flows) steam drum blow down or steam releases of the system are introduced to the post combustion products flow, this enables the heat losses of steam release to be used to assist the thermal efficiency of the combustion sections and also assist with water recovery.

Thermal gradient and overall thermal efficiency

[0467] In the specific embodiments and processes described herein, the fuel combustion method and apparatus are distinguished over the prior art by virtue of continuous, or substantially continuous operation of the whole process, which provides improved heat recovery from a continuous stream of combustion products, and by use of the recovered heat to pre-heat the fuel which is fed into the combustion units. Because heat is being continuously recovered from combustion products and because the recovered heat is continuously used to preheat the fuel entering the combustion units, this enables greater thermal efficiency than in prior art combustion systems, particularly those which a batch processing model.

[0468] Continuous operation comprises substantially continuously, comprising: substantially continuous combustion in said first combustion unit (A); substantially continuous transfer of combustion products out of said first combustion unit into said heat recovery unit (C); substantially continuous transfer of combustion products out of said first combustion unit into said heat recovery unit (D); and substantially continuous use of heat recovered from said heat recovery unit for pre-heating a flow of fuel into said combustion unit.

[0469] In various specific embodiments and methods described herein C0₂ is continuously produced and is used continuously in a Sabatier process to produce methane CH₄. In some specific methods and embodiments herein, if excess methane is generated, in excess of the amount of methane which can be used as a combustion fuel in a second or subsequent combustion unit, the excess methane can be used for other purposes outside the combustion system, e.g. transport fuel, but in normal operation the specific embodiments and methods herein continuously produce C0₂ and methane CH _, where the methane is continuously fed back into the combustion units.

[0470] Further, by the burning of the methane CH in a second and in subsequent combustion units in a series of combustion units, the higher combustion temperature obtained by burning methane, of the order of 2000°C acts to reduce particle size from the incoming combustion products from the preceding combustion stage, which is where combustion may have occurred at a lower temperature. Having a reduced particle size from the higher temperature combustion units results in a relatively more pure gas output, with the object of a higher proportion of only water H₂0 and C0₂ entering the heat recovery stage (C) and final cooling/cryogenic stage (D). The input to the Sabatier process is therefore a purer mix of water H₂0 and C0₂.

[0471] In continuous operation, combustion products including C0₂ gas, H20, are continuously produced, including hot gases and steam at above atmospheric pressure which can be used to continuously generate electricity, and which in turn can be used to produce methane using a Sabatier process. Any excess gases which are produced, including methane, which are over and above the amount of gases which are needed to maintain continuous operation of the overall process can be buffer stored in storage units for later use, or in the case of methane CH4 can be used as an excess by-product as a transport fuel.

Summary

[0472] This is a complex energy system with efficiencies and ways of operation not used in mass electricity generation power plants/stations at the time of writing.

[0473] It is designed to not only to be more efficient in terms of thermal efficiency using waste heat in post combustion flows and recovered heat into fuel or oxygen entering combustion, but to not release C0 into the atmosphere or low amounts of C0₂ to atmosphere compared to current standard fuel burning in power stations.

[0474] The system requires supplies of Oxygen and Hydrogen as elemental gases and the system uses water electrolysis, which occurs when an electrical current is passed through a body of water or water/impurities/salts, between two separated electrodes that enable an electrical circuit. The electrolysis facility could be some distance from the power station use, which would require pipes to carry the separate Oxygen and Hydrogen gases, it is however more likely they will be close to fuel burning site, as electrical power is being generated on site. The electrolysis process if C0₂ is dissolved in the water can make use of a salt (in this case Calcium Oxide CaO) to improve ion formation and give a small electrolysis cell efficiency, in so doing causing Calcium Carbonate CaC0₃ to form on one the electrodes as a solid (which would need to removed periodically), This CaC0₃ can be used as by product or if mixed as slurry with Sulphur Dioxide S0₂ gas can create Calcium Sulphate CaS0 which is a form of building cement, so by dissolving C0₂ into water an electrolysis cell efficiency is possible which creates a useful by product. If the creation of these by products is not required the electrolysis can take place and no Calcium Oxide need be added to the electrolysis cell.

[0475] The fuel is combusted with Oxygen (both of which may be pre heated with recovered heat) which offers an immediate efficiency in that in combustion the oxygen component of air used in most mass power generation systems is 21%, the 78% of Nitrogen gas component of air is not used thereby heat is not wasted in heating this extra mass, it also reduces the formation of Nitrous oxides as the Nitrogen component of air is absent.

[0476] This also gives additional control of the combustion process; Oxygen and fuel can be increased or decreased depending upon the fuel requirements and variations.

[0477] Post combustion in the primary or initial combustion component A, the post combustion flue products composition should be mostly hot C0₂ and H₂0 (which could be at high pressure), if the fuel combustion has other products these may need removing, char and ash can also be removed and recycled into fuel or left to combust in the second component B. In combusting in the correct mixture of Oxygen and fuel, complete combustion or near complete combustion can be achieved which will also give higher temperatures of combustion than currently in use, but also create a post combustion flue products stream more composed of C0₂ and H₂0. This then flows to component B which is a secondary combustion section recommended as using Methane or Alcohol, the heat from component A post combustion flue products aiding thermal efficiency, thus for the same power output less fuel is required than if not joined symbiotically and connected in series, component B uses Oxygen which can be pre heated used recovered heat, rather than air and in the case of Methane CH as fuel this can also be pre heated with recovered heat giving further thermal efficiency improvements not used currently in power generation, in that waste heat can be re-introduced to use to raise steam or to power turbines, in a way other than as combustion of fuel directly, improving efficiency and heat extracted from fuel, using heat recovery.

[0478] The post combustion flue components of A enter the combustion section of component B (an additional stream of hot C0₂ from an external source can also be blended to this flow to increase CH₄ production post combustion), where fuel and Oxygen are combusted giving additional C0₂ and H₂0 giving a post combustion flue products from component B of mostly hot C0₂ and H₂0 (which could be at high pressure).

[0479] At this point in the system there is choice or modality option in design, a further component B combustion section could be added using Methane or Alcohol as fuel and Oxygen combustion, to generate a higher electrical output, and further component B designs to whatever design requirements are. The further option is for post component B flue products, to go through a heat extraction phase of component C (which could provide the heat for the pre heating of fuels and Oxygen or could power a turbine by steam raising or as a gas turbine), once through component C the now post C flue product flows can be cooled and the water extracted, leaving a cooled flow of mostly C0 and moves to component D .This C0₂ as gas can then be put through a Sabatier reaction process where it is combined with Hydrogen gas H₂ at temperature and pressure to make Methane CH₄ and Water H₂0, given the Sabatier reaction is not described in science as 100% efficient, any post Sabatier reaction products stream will be composed of CH₄, and H₂0 and also some unreacted H₂ and C0₂. The C0₂ can be removed as it dissolves in H₂0, H₂ and CH gases do not dissolve in H₂0. Ideally all H₂0 and C0₂ should be removed before the product flow moves to the cryogenic section, where the CH and H₂ are cooled to very low temperatures the critical value being the liquefication of CH₄, the H₂ gas having a lower liquefication point and thus should remain a gas. In cryogenically cooling and other cooling possibilities heat can be recovered and placed back into the combustion sections via pre heated fuel or Oxygen giving a further thermal efficiency.

[0480] At the end of component D and post Sabatier and cryogenic cooling the process should have condensed out water (to be used or recovered), should have removed C0₂ into the cooling water/ice, or in an early part of the cryogenic process, leaving the CH to be liquefied and the H₂ as gas (dried) which can be used in generator cooling as currently done and then re-introduced into the Sabatier process or used as combustion fuel, the liquefied (and dried) CH4 going either to store or to be used as a coolant , prior to be used as a fuel in the power generation system or treated to become CH for use in the gas supply system.

[0481] Whilst this system has efficiencies not currently used in electricity generation which offer significant improvements, and can produce little or no C0₂ as it converts it to CH , it can generate large outputs of electrical energy and can be designed to have varying electrical and CH to grid outputs depending upon the design requirements, it is thought of as base load mass power generation system that can adjust to fuel type and use low grade biomass fuels not currently used and adjust to seasonal electricity requirements, as well as having scope for difficult waste products as it uses high temperature combustion.

[0482] There are modalities (see modifications and variations) that allow this patent application design to release C0₂ to atmosphere as gas or solid and also a modality to use the post Sabatier reaction products with the water removed, mostly composed of CH and unreacted C0₂ and H₂ gases to be diverted to combustion rather than processing and separation, giving some control over hydrogen required and how much water electrolysis is needed, thereby enabling balancing and efficiency designs of CH₄ gas production to have more flexibility of the resources and operation of the electricity power stations.

Claims

1. A fuel combustion apparatus comprising: at least one combustion unit (A, B); each said combustion unit being operable to receive a fuel, combust said fuel with oxygen, and produce combustion products; at least one heat recovery stage (C); said at least one heat recovery stage (C) being operable to receive said combustion products and to recover heat from said combustion products; and at least one cooling stage (D); said at least one cooling stage (D) being operable to receive output products of said at least one heat recovery stage.

2. The fuel combustion apparatus as claimed in claim 1 , wherein said combustion products are input into said heat recovery unit (C); said heat recovery unit cools said combustion products, and cooled said second combustion products are output from said heat recovery unit.

3. The fuel combustion apparatus as claimed in claim 1 or 2, comprising: a first combustion unit (A); said first combustion unit being operable to receive a first fuel, combust said first fuel with oxygen, and produce first combustion products; and a second combustion unit (B); said second combustion unit being operable to receive a second fuel, combust said second fuel with oxygen, and produce second combustion products; wherein said first combustion products are fed into said second combustion unit along with said second fuel.

4. The fuel combustion apparatus as claimed in claim 3, wherein said second combustion products are fed into said heat recovery stage (C).

5. The fuel combustion apparatus as claimed in any one of the preceding claims, further comprising an electrolysis unit (F) said electrolysis unit receiving electrical power generated from a said combustion unit.

6. The fuel combustion apparatus as claimed in any one of the preceding claims, wherein a first fuel fed into a first said combustion unit (A) comprises a fuel selected from the set: methane; an alcohol; tyre crumb; biomass; oil; waxes; wood waste.

7. The fuel combustion apparatus as claimed in any one of the preceding claims, wherein a second fuel fed into a second said combustion unit (B) comprises a gas selected from the set: natural gas; methane.

8. The fuel combustion system as claimed in any one of the preceding claims, wherein a said combustion unit comprises one or more steam turbines, said one or more steam turbines comprising one or more mechanical drive outputs for, in use, providing mechanical power.

9. The fuel combustion system as claimed in claim 8, further comprising: one or more electrical generators connected to said one or more mechanical drive outputs for generation of electricity.

10. The fuel combustion system as claimed in any one of the preceding claims, comprising a Sabatier reaction chamber, wherein hydrogen gas (H ) is mixed with carbon dioxide (C0₂) gas and is subjected to a controlled temperature and a controlled pressure to produce methane (CH ) and water (H₂0).

11. The fuel combustion system as claimed in claim 1 , comprising a plurality of said combustion units, and one or more said heat recovery units wherein said one or more heat recovery units are arranged to recover heat from combustion products output by said plurality of combustion units.

12. The fuel combustion system as claimed in claim 1 , wherein at least one of said combustion units uses air drafted combustion.

13. The fuel combustion system as claimed in claim 1 , wherein enough free oxygen is introduced into said at least one combustion unit to combust all of the fuel introduced into at least one combustion unit.

14. The fuel combustion system as claimed in claim 1 , wherein pure oxygen is introduced into a said at least one combustion unit without any air.

15. The fuel combustion system as claimed in claim 1 , comprising a plurality of combustion units, wherein said plurality of combustion units are placed in sequence, wherein a first said combustion unit (A) carries out a first combustion with a first fuel, resulting in a first set of combustion products; and said first set of combustion products are fed into a second said combustion unit (B) which carries out a second combustion, with a second fuel, resulting in a second set of combustion products.

16. The fuel combustion system as claimed in claim 15, wherein substantially pure oxygen is introduced into said second combustion unit, without any air and said fuel comprises methane, said combustion having a temperature of greater than 2,000°C.

17. The fuel combustion system as claimed in claim 15 or 16, wherein said second set of combustion products are introduced into said at least one heat recovery unit.

18. The fuel combustion system as claimed in any one of claims 15 to

17, wherein said second set of combustion products are introduced into said at least one cooling unit.

19. The fuel combustion system as claimed in any one of claim 15 to

18, further comprising a third combustion unit, wherein said second set of combustion products are introduced into said third combustion units.

20. The fuel combustion system as claimed in any one of the preceding claims, further comprising a Sabatier reaction unit (SAB), wherein a said set of combustion products are introduced into said Sabatier reaction unit.

21. The fuel combustion system as claimed in any one of the preceding claims, comprising a first said combustion unit (A) as an initial combustion stage, wherein a fuel input into said first combustion unit is selected from the set: biomass; bio solids; heavy oil; bio oils; bunker fuel; coal; powdered tyre waste without metal; tyre derived fuel oil; an alcohol; fatty oils; waxes; wood waste.

22. The fuel combustion system as claimed in any one of the preceding claims, comprising a first combustion unit (A) and a second combustion unit (B) wherein the fuel fed into said second combustion unit is selected from the set: natural gas; methane.

23. The fuel combustion system as claimed in any one of the preceding claims, comprising a plurality of combustion units, said plurality of combustion units being arranged in series, such that the combustion products of a preceding combustion unit are fed into a successive said combustion unit .

24. The fuel combustion system as claimed in claim 22, wherein combustion units of a said successive combustion unit are fed into one or a plurality of further combustion units arranged in series; and so that the output combustion products of one of said further combustion units is fed serially into another successive one of said further combustion units.

25. The fuel combustion system as claimed in claim 22, further comprising a plurality of further combustion units, said plurality of further combustion units being arranged in parallel, such that the combustion products of a preceding combustion unit are fed in parallel to said plurality of further combustion units.

26. The fuel combustion system as claimed in claim 23 or 24, wherein a fuel fed into said plurality further combustion units is selected from the set: natural gas; methane.

27. The fuel combustion system as claimed in any one of the preceding claims, wherein a flow of synthesised methane is input into said at least one combustion unit.

28. The fuel combustion system as claimed in claim 1 , comprising: a first said combustion unit (A) for carrying out a first stage of combustion; a second said combustion (B) unit for carrying out a second stage of combustion; and a third said combustion unit (C) for carrying out a third stage of combustion; wherein said first and second combustion units are operable to combust oxygen with a fuel; and said third combustion stage combusts methane and/or natural gas as a fuel.

29. The fuel combustion system as claimed in any one of the preceding claims, comprising a first said combustion unit (A) as first combustion stage, wherein a fuel input into a first said combustion unit has a moisture content of 10% or more by weight.

30. The fuel combustion system as claimed in any one of the preceding claims, comprising one or a plurality of said combustion units, and at least one heat exchanger, wherein said heat exchanger is used to pre-heat oxygen prior to introduction in to said one or plurality of said combustion units.

31. The fuel combustion system as claimed in any one of the preceding claims, comprising at least one electrolysis unit for generating oxygen and hydrogen from electrolysis of water.

32. The fuel combustion system as claimed in any one of the preceding claims, comprising at least one electrolysis unit for generating hydrogen from electrolysis of water; and at least one Sabatier reactor for producing methane from hydrogen produced by said electrolysis unit.

33. The fuel combustion system as claimed in claim 1, comprising: a first combustion unit (A) for performing a first combustion stage; a second combustion unit (B) for performing a second combustion stage; said first combustion unit (A) feeding a first set of combustion products from said first combustion stage into said second combustion unit (B); a heat recovery stage (C) for recovering heat from a second set of combustion products generated by said second combustion unit; and a cooling component (D) for cooling and output of said heat recovery stage

C.

34. The fuel combustion system as claimed in any one of the preceding claims, in which a continuous flow of combustion products of decreasing volume occurs between said heat recovery stage (C) and said cooling stage (D), and further comprising at least one turbine introduced into said continuous flow of combustion products.

35. The fuel combustion system as claimed in any one of the preceding claims, in which said cooling component (D) comprises one or more gas heat exchangers and one or more water heat exchangers or a combination thereof, to reduce the temperature of post combustion products within a range 0°C to 5°C; and wherein said cooling component is operable to remove water vapour from said post combustion products.

36. The fuel combustion system as claimed in claim 1 , comprising at least one turbine, wherein combustion products from a said combustion unit is used to power said turbine; and further comprising an electrical generator driven by said turbine for producing electricity.

37. The fuel combustion system as claimed in claim 1 , comprising a heat exchanger for preheating fuel and/or oxygen prior to combustion in a first said combustion unit (A); wherein the heat recovery stage (C) and/or the cooling stage (D) is used to preheat fuel and/or oxygen prior to combustion in said first heat exchange unit (A); wherein a fuel and/or oxygen is routed through said one or more heat exchange units prior to introduction to said one or more combustion units; and wherein said pre-heated fuel comprises fuel selected from the set: a solid fuel; a fuel containing physical solids; a gaseous fuel.

38. The fuel combustion system as claimed in any one of the preceding claims, wherein said cooling section comprises a Sabatier reaction chamber capable of receiving a continuous flow of cooled combustion stage products.

39. The fuel combustion system as claimed in claim 38, wherein said Sabatier reaction is operated with the following parameters: input ratio of hydrogen gas (H ) to carbon dioxide (C0₂), ratio 4:1 standard temperature and pressure; reaction temperature of 300°C to 400°C and pressure of 50 psi/345 kPa; output pressure 50 psi/345 kPa; cooling of Sabatier reaction products to 200°C or below.

40. The fuel combustion system as claimed in claim 39, wherein the Sabatier reaction products are further cooled to a temperature in the range 0°C to 5°C; and said reaction products are passed through ice in a vertical column in order to remove carbon dioxide C0₂.

41. The fuel combustion system as claimed in claim 40, comprising a further cooling stage for cooling said Sabatier reaction products to -160°C or lower to liquefy methane CH₄.

42. The fuel combustion system as claimed in any one of the preceding claims, comprising at least one combustion unit, wherein steam is injected into a pre - combustion fuel and/or oxygen flow prior to entry into said at least one combustion unit; and/or into a flow of post combustion products at an output of said at least one combustion unit.

43. The fuel combustion system as claimed in claim 1 , comprising: a cement making plant or cement clinker plant, wherein said cement making or cement clinker plant produces heat, carbon dioxide (C0₂), and water H₂0, wherein said heat, carbon dioxide C0₂, and water H₂0 are fed into a precombustion fuel flow for combustion in said at least one heat combustion unit; and/or said heat, carbon dioxide C0₂ and water H₂0 are fed into an output combustion product flow from said at least one combustion unit.

44. The fuel combustion system as claimed in claim 43, further comprising a Sabatier reaction chamber, wherein carbon dioxide C0₂ produced by said cement making plant or cement clinker plant is combined with methane CH and input into said Sabatier reaction chamber.

45. The fuel combustion system as claimed in any one of the preceding claims, comprising at least one cooling unit and at least one electrolysis unit, wherein water containing absorbed or dissolved carbon dioxide C0 produced by said at least one cooling unit is used in said at least one electrolysis unit.

46. The fuel combustion system as claimed in claim 45, wherein said water has an added salt, said salt selected from the set: any salt; calcium oxide.

47. The fuel combustion system as claimed in any one of the preceding claims, comprising a single combustion unit, wherein said combustion unit is pressurised using a mechanical constriction.

48. The fuel combustion system as claimed in claim 1 , comprising a two-stage sequential combustion system comprising a first stage combustion unit (A) which feeds combustion products into a second stage combustion unit (B); wherein said two-stage sequential combustion system is used to combust natural gas and synthesised methane CH₄; and further comprising an external source of heat and carbon dioxide C0₂; wherein said second stage combustion unit is used to generate electricity; and said electricity generated by said second combustion unit is used to power an electrolysis unit for electrolysis of water H₂0; wherein said electrolysis of water produces hydrogen H₂; and said hydrogen is reacted in a Sabatier reaction to convert carbon dioxide C0 output by combustion of said first or second stage combustion unit combustion into methane CH₄.

49. The fuel combustion system as claimed in claim 1 , comprising a Sabatier reaction chamber having a cooling mechanism to produce methane CH which receives an external carbon dioxide C0₂ supply, and which electrolyses water H₂0 to produce hydrogen H₂ for use in said Sabatier reaction chamber.

50. A fuel combustion system as claimed in any one of preceding claims comprising: one or more combustion units; and/or one or more water electrolysis units; and/or one or more remote water electrolysis units; and/or one or more heat recovery units; and/or one or more cooling units; and/or one or more water cleaning units; and/or one or more Sabatier reaction chamber process units; and/or one or more remote satellite Sabatier reaction; and/or one or more gas separation units; and/or one or more water removal units; and/or one or more electricity generators, at least one unit being so arranged to make a continuous high electrical energy output to a distributed electrical system and/or high-power mechanical output, continuously and related in arrangement to bring about efficiencies of heat, fuel and reduced direct emissions of combustion products to the atmosphere; wherein the arrangement of said units provides an excess of synthesised methane in a continuous output, and where a Sabatier reaction is used.

51. A method of combusting a fuel comprising: combusting a first fuel in a first combustion unit (A) in a first stage of combustion to produce a flow of first combustion products, said flow of first combustion products comprising high pressure and / or high velocity C0 and high pressure and/ or high velocity H₂0; passing said first combustion products into a heat recovery stage (C) for recovery of heat from said first combustion products; feeding a stream of cooled said first combustion products output from said heat recovery stage (C) into a cooling stage (D).

52. The method of combusting fuel as claimed in claim 51 , comprising: combusting said flow of first combustion products with a second fuel and with oxygen in a second combustion unit (B) in a second stage of combustion, to produce a flow of second combustion products from said second stage; feeding said flow of second combustion products from said second stage into at least one heat recovery unit (C), for recovery of heat from said second combustion products; and feeding cooled said second combustion products into a cooling stage (D).

53. The method as claimed in claim 52 or 52, wherein said first fuel comprises a fuel selected from the set: methane; alcohols; tyre crumb; biomass; mineral oil; waxes; wood waste.

54. The method as claimed in any one of claims 52 to 53, wherein said second fuel comprises a gas selected from the set: natural gas; methane.

55. The method as claimed in any one of claims 52 to 54, further comprising using a flow of second combustion products as a coolant.

56. The method as claimed in any one of claims 52 to 55, comprising a first said combustion unit (A) as first combustion stage, wherein a fuel input into said first combustion unit has a moisture content of 10% or more by weight.

57. The method as claimed in any one of claims 52 to 56, comprising carrying out a Sabatier reaction, wherein said Sabatier reaction is operated with the following parameters: input ratio of hydrogen gas (H₂) to carbon dioxide (C0₂), ratio 4:1 standard temperature and pressure; reaction temperature of 300°C to 400°C and pressure of 50 psi/345 kPa; output pressure 50 psi/345 kPa; cooling of Sabatier reaction products to 200°C or below.

58. The method as claimed in claim 57, wherein the Sabatier reaction products are further cooled to a temperature in the range 0°C to 5°C; and said reaction products are passed through ice in a vertical column in order to remove carbon dioxide C0 .

59. The method as claimed in claim 57 or 58, comprising a further cooling stage for cooling said Sabatier reaction products to -160°C or lower to liquefy methane CH₄.

60. The method as claimed in any one of claims 52 to 59, wherein water containing absorbed or dissolved carbon dioxide C0₂ produced by said at least one cooling unit is used in least one electrolysis unit.

61. The method as claimed in claim 60, wherein said water has an added salt, said salt selected from the set: any salt; calcium oxide.

62. The method as claimed in any one of claims 52 to 61 , operated substantially continuously, comprising: substantially continuous combustion in said first combustion unit (A); substantially continuous transfer of combustion products out of said first combustion unit into said heat recovery unit (C); substantially continuous transfer of combustion products out of said first combustion unit into said heat recovery unit (D); and substantially continuous use of heat recovered from said heat recovery unit for pre-heating a flow of fuel into said combustion unit.

The method as claimed in any one of claims 52 to 62, operated as a substantially continuous process, wherein there exists a continuous and/or permanent thermal gradient between (i) a relatively hotter said combustion unit at a first temperature; (ii) a said heat recovery unit at an intermediate second temperature; and (iii) a relatively cooler cooling stage (C) at and a relatively cooler cooling stage (D) at a third relatively lower temperature.