WO2007144661A2 - Procédé de production d'énergie électrique - Google Patents

Procédé de production d'énergie électrique Download PDF

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Publication number
WO2007144661A2
WO2007144661A2 PCT/GB2007/002259 GB2007002259W WO2007144661A2 WO 2007144661 A2 WO2007144661 A2 WO 2007144661A2 GB 2007002259 W GB2007002259 W GB 2007002259W WO 2007144661 A2 WO2007144661 A2 WO 2007144661A2
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WIPO (PCT)
Prior art keywords
gas turbine
steam
stream
fuel
heavy
Prior art date
Application number
PCT/GB2007/002259
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English (en)
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WO2007144661A3 (fr
Inventor
Michael Ian Duckels
Ian Hole
Original Assignee
Quadrise Limited
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Publication date
Application filed by Quadrise Limited filed Critical Quadrise Limited
Publication of WO2007144661A2 publication Critical patent/WO2007144661A2/fr
Publication of WO2007144661A3 publication Critical patent/WO2007144661A3/fr

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
    • F01K23/00—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids
    • F01K23/02—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled
    • F01K23/06—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled combustion heat from one cycle heating the fluid in another cycle
    • F01K23/065—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled combustion heat from one cycle heating the fluid in another cycle the combustion taking place in an internal combustion piston engine, e.g. a diesel engine
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
    • F01K23/00—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids
    • F01K23/02—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled
    • F01K23/06—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled combustion heat from one cycle heating the fluid in another cycle
    • F01K23/064—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled combustion heat from one cycle heating the fluid in another cycle in combination with an industrial process, e.g. chemical, metallurgical
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
    • F01K23/00—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids
    • F01K23/02—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled
    • F01K23/06—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled combustion heat from one cycle heating the fluid in another cycle
    • F01K23/10—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled combustion heat from one cycle heating the fluid in another cycle with exhaust fluid of one cycle heating the fluid in another cycle
    • F01K23/103—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled combustion heat from one cycle heating the fluid in another cycle with exhaust fluid of one cycle heating the fluid in another cycle with afterburner in exhaust boiler
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E20/00—Combustion technologies with mitigation potential
    • Y02E20/16—Combined cycle power plant [CCPP], or combined cycle gas turbine [CCGT]

Definitions

  • the present invention relates to methods for the generation of electrical power.
  • the invention relates to the integrated processing and use of a mix of hydrocarbon streams present in heavy oils for re-powering an existing boiler and steam turbine power generation system.
  • fuel for the gas turbine must be gas or a high- quality, and hence expensive, liquid distillate fuel oil such as No. 1 Oil (kerosene) or No. 2 Oil (gasoil).
  • liquid distillate fuel oil such as No. 1 Oil (kerosene) or No. 2 Oil (gasoil).
  • gas turbine fuels are generally purchased in addition to the fuel used for the boiler.
  • the heavy hydrocarbon streams also contain compounds of molecular weight of about 300 to about 450 comprised primarily of hydrogen and carbon together with some sulphur and nitrogen and, on occasion, high atomic weight atoms such as vanadium or nickel. Such compounds boil below about 375 0 C under vacuum of less than 20 mbara (2000 Paa). Compounds with molecular weights greater than about 450 boil above 375°C under vacuum of less than 20 mbara (2000 Paa) and, as molecular weight increases, an increasing proportion of the compounds boiling in a given temperature and pressure range contain increasing proportions of heteroatoms such as nitrogen, oxygen, sulphur and high atomic weight atoms such as vanadium and nickel. Complex high molecular weight hydrocarbons with high levels of sulphur and nitrogen typically containing high atomic weight atoms such as vanadium or nickel are classified by oil professionals as asphaltenes and are defined by their insolubility in light paraffins.
  • Light sales oils such as gasolines of API >50, and distillates such as No 1. oil (kerosene) or No. 2 Oil (gasoil) of API 30 to 45 contain near-zero levels of high molecular weight (>300) compounds (API is a measure of density commonly used in the field of oil processing).
  • Crude oils of API > 20 contain a relatively low proportion of high molecular weight compounds and are routinely processed by oil refineries to distil out the lower molecular weight compounds to make light sales oils by blending or cracking, thereby leaving residues that may not be used to make premium light sales oils but are instead blended to make heavy fuel oils suitable for combustion applications such as oil-fired thermal boilers.
  • Heavy crude oils of API ⁇ 20 contain relatively low proportions of low molecular weight compounds and are less suitable for processing in conventional oil refineries but are suitable for combustion applications such as oil-fired thermal boilers. Heavy oils such as No 6. Oil or heavy fuel oil with a viscosity in the range 180 to 1 ,00OcSt at 50 0 C, low- API crude oil or refinery distillation residues or other refinery residual streams that result from separation or conversion processes within an oil refinery contain a wide variety of constituents some of which pose both environmental and operational problems as they contain, among others, sulphur, nitrogen and metals (particularly vanadium).
  • the level of these pollutants must be reduced to near- zero when the fuel stream is to be combusted in precision equipment such as gas turbines.
  • maximum levels of various trace metals in gas turbine fuel oils have been established in ASTM D2880-03 at 0.5ppm for each of vanadium, sodium plus potassium, calcium and lead.
  • the present invention therefore provides a method for the generation of electrical power which comprises the steps of: (a) separating a starting liquid oil feedstock into at least one light liquid stream and one heavy stream;
  • the invention provides an alternative method for the generation of electrical power which comprises the steps of:
  • exhaust gas heat from the gas turbine and/or the diesel generator is utilised in the separation step a).
  • some of the exhaust gas heat may be used to heat the starting liquid oil feedstock in the separation step.
  • some of the exhaust gas heat may also be used in raising steam.
  • a relatively low-cost starting liquid heavy oil feedstock (suitably with a viscosity of less than 38OcSt at 95°C) is processed into two or more combustion fuel streams: a high-quality light liquid stream to feed a gas turbine or diesel generator, a low-quality heavy stream which can be used to generate steam to drive a steam turbine, and optionally also a gaseous stream suitable for combustion in a gas turbine.
  • the heavy stream may be used to fire a steam-raising boiler. Electricity is generated both by the gas turbine or diesel generator and by the steam turbine.
  • the starting liquid oil feedstock for the methods of the invention may be any oil which contains at least some fractions which, if separated out, are suitable for use as a fuel for a gas turbine and/or for a diesel generator.
  • the starting liquid oil feedstock will contain sufficient separable fractions to provide a sufficient quantity of fuel to fuel the re-powering gas turbine(s) and/or diesel generator(s).
  • the proportion of the re-powering equipment fuel maybe as little as less than 10% by weight of the starting heavy oil feedstock.
  • the re-powering equipment fuel should be between about 25% by weight and about 45% by weight of the starting heavy oil feedstock.
  • the re- powering equipment fuel should be more than about 30% by weight and preferably. more than about 60% by weight of the starting heavy oil feedstock.
  • the starting liquid oil feedstock may be a fuel which is suitable for combustion in a conventional power station boiler to generate steam.
  • it may be a heavy oil stream or heavy crude oil of the type that is normally processed in an oil refinery, or it may be the heavy product of processing crude oil in a refinery, or it may be a newly arising heavy oil stream or heavy crude oil for which no routine processing route has yet been established.
  • Such starting oil feedstocks include heavy fuel oil, heavy oil streams, residue streams or heavy crude oils with a density of more than about 0.935 kg/m 3 at 15°C, and/or a viscosity greater than about 1 OOcSt at 50 0 C, and/or a vanadium content greater than 0.5ppm, and/or a vanadium plus nickel content greater than 0.5ppm, and/or a sodium plus potassium content greater than 0.5ppm, and/or a calcium content greater than 0.5ppm, and/or a lead content greater than 0.5ppm.
  • Step (a) of the methods of the invention produces at least one light liquid stream which is suitable for combusting in either a gas turbine or a diesel generator. More than one light liquid stream may be produced. For example, in one embodiment, at least two different light liquid streams are produced, one of which is suitable for use in a gas turbine and one of which is suitable for use in a diesel generator.
  • a liquid fuel oil should satisfy the requirements of ASTM D2880-03, the disclosure of which is incorporated by reference herein.
  • light liquid streams that are suitable for combustion in a gas turbine preferably have levels of below 0.5ppm for each of vanadium, of sodium plus potassium, of calcium and of lead. If the gas turbine fuel has low levels of sulphur (for example below about 0.2% by weight), then the exhaust gases from the gas turbine may meet the emissions requirements for sulphur oxides without requiring any treatment.
  • Suitable liquid gas turbine fuels include hydrocarbon streams of viscosity less than about 2.4cSt at 40 0 C; hydrocarbon streams of viscosity greater than about 2.4cSt at 50 0 C and less than about 5OcSt at 100 0 C; and hydrocarbon streams of greater than about 50 cSt at 100 0 C.
  • the viscosity of a suitable liquid gas turbine fuel is very dependent on the gas turbine fuel delivery system.
  • the separation and processing of the starting feedstock also provides a gaseous stream which is suitable for combustion in a gas turbine.
  • a gaseous stream is gaseous at the pressure and temperature of the combustion air entering the gas turbine combustor, and should be free of entrained solid particles.
  • Suitable gas turbine fuels include gas at a pressure greater than the pressure of the gas turbine combustor comprised mainly of light hydrocarbons, hydrogen sulphide and steam. The calorific value of this gas stream may be adjusted by increasing or decreasing the quantity of steam and water used in the processing of the heavy oil where this steam and water end up in the gas stream to the gas turbine.
  • the liquid stream For use in a diesel generator, the liquid stream generally requires a viscosity of greater than about 1.1 cSt at 50°C and less than about 3OcSt at the conditions at the fuel injection point. This typically limits diesel fuel viscosity to less than about 80OcSt at 5O 0 C. There are no strict limits on the level of vanadium, sodium plus potassium, calcium and/or lead contained in diesel fuel. This allows heavier streams to be used as a suitable fuel where they have a viscosity of less than about 3OcSt under the conditions at the fuel injection point.
  • a fuel for the diesel generator which will have low levels of sulphur (for example below about 0.2% by weight).
  • the use of such fuels is advantageous, as the exhaust gases from the generator may comply with the emission limits for sulphur oxides without requiring any treatment before they can be vented to the atmosphere.
  • the oil separation step (a) also produces a heavy stream which is unsuitable for combustion in a gas turbine or for direct combustion in a diesel generator.
  • This stream preferably has a density of greater than about 0.98 kg/m at 15 0 C and a viscosity greater than about 50OcSt at 100°C.
  • the heavy stream will also usually have levels of metals such as vanadium significantly in excess of the maximum limits for a gas turbine fuel.
  • At least a part of the heavy stream is mixed with water and a suitable stabilising additive to produce an emulsion fuel.
  • a suitable stabilising additive to produce an emulsion fuel.
  • Such emulsions fuels are low- viscosity oil-in- water emulsions in which the heavy oil is effectively pre-atomised, and may be stored conventionally under ambient conditions or delivered to the burner as required.
  • the emulsion is preferably sufficiently stable for it to be pumpable and storable under ambient conditions.
  • the emulsion may consist of between about 28% by weight of water to about 40% by weight of water but is preferably less than about 35% by weight water. Any additive which serves to stabilise the emulsion may be used.
  • the proportion of stabilising additive is typically less than about 1% by weight, preferably less than about 0.6% by weight of the emulsion.
  • the formation of such oil-in- water emulsion fuels is well known in the art, and is disclosed in for example US 4,943,390, US 6,194,472 and US Patent Application Publication No. 20030131526, the disclosures of which are incorporated by reference herein.
  • Suitable stabilising additives are well known in the art. All classes of interfacially active material known for the stabilisation of an oil-in-water emulsions can be used. Such stabilisers are generally water soluble interfacially active materials. For example, water soluble non-ionic, cationic and anionic interfacially active materials or mixtures thereof can be used. Suitable cationic interfacially active materials include quaternary fatty alkyl trimethylenediamine ethoxylates, and N-tallow alkyl- 1 ,3-diaminopropane, which are particularly good at stabilising heavy hydrocarbon emulsions. The heavy stream may be cooled before it is emulsified. Alternatively, it may be emulsified hot.
  • the emulsification may have to be carried out at elevated pressure in order to prevent the water used for the emulsification from boiling.
  • the majority (for example greater than about 80% by weight, preferably greater then about 90% by weight) or all of the emulsion fuel will be combusted to raise steam to drive a steam turbine.
  • some of the emulsion fuel may be sold or used for other purposes.
  • Any of the heavy stream not utilised to make an emulsion fuel may optionally also be combusted to generate steam. Part of the heavy stream may be combusted directly, but it will usually require modification before it can be combusted.
  • the viscosity of the heavy stream will often be in excess of that required to provide adequate atomisation by the fuel injectors employed to introduce the fuel into the combustion gas stream.
  • a fraction of one or more of the light streams produced is step (a) may be mixed with the high- viscosity residue to reduce its viscosity.
  • Some of the heavy stream and/or the emulsion fuel may also optionally be used to provide heat for the separation step (a).
  • some of the heavy stream and/or the emulsion fuel may be used in a direct fired heater to heat the starting liquid oil feedstock for the separation step (a).
  • the separation step (a) may use any process or combination of processes known in the art for the splitting of heavy fuel oils into separate fractions.
  • Known processes that may be used singly or in combination include atmospheric flashing or atmospheric distillation; vacuum flashing or vacuum distillation; "steam stripping"; solvent separation using a light paraffin such as propane, butane or pentane; thermal cracking; and thermal cracking in the presence of steam.
  • Atmospheric and vacuum flashing, and distillation and steam stripping are well known refining processes where different constituents of the heavy oil feedstock are separated according to their boiling points and vapour pressures with the objective of producing individual fractions that either meet a specification of a saleable product or that may be blended with other streams to make a saleable product.
  • the process heat is provided using a direct fired heater.
  • Solvent separation or solvent de-asphalting is a well known process where the high molecular weight asphaltenic molecules that largely contain the high atomic weight atoms such as vanadium or nickel are precipitated using a solvent such as propane, butane or pentane.
  • the process heat is provided using a direct fired heater together with the use of medium and low pressure steam.
  • Thermal cracking is a well known process * where heat, supplied by a direct fired heater, is used to raise the temperature of the feedstock to a point where some of the larger molecules crack producing smaller molecules together with increased levels of high molecular weight asphaltenic molecules.
  • heat required for the separation step (a) can be provided by any suitable means, including the type of direct fired heaters generally used in an oil refinery context.
  • at least some of the heat required for the separation step is provided by the exhaust gases from the gas turbine or diesel generator. Exhaust gases exiting the gas turbine or a diesel generator will be at a high temperature (greater than about 400°C, generally above about 550°C and in some cases above about 65O 0 C).
  • Further heat for the separation process can if necessary be provided by heat exchange between the products of the separation process and the starting feedstock.
  • These heat sources can partially or completely replace the direct fired heaters which are conventionally utilised for oil separation in a refinery context.
  • the hot exhaust gases from the gas turbine or diesel generator may preferably be used to directly heat the starting oil feedstock by circulating the oil feedstock inside tubes suspended in the hot exhaust gases.
  • the hot exhaust gases may be used to produce steam or re-heat steam which is then used to heat the starting oil feedstock in a steam/oil heat exchanger.
  • the exhaust gas from the gas turbine or diesel generator may be directed to a process heat recovery steam generator in which they are used to both provide heat for the feedstock separation step and to heat steam which may be used to drive a steam turbine.
  • This steam turbine will preferably be the same steam turbine that is driven by the combustion of the emulsion fuel of the method of the invention, hi one arrangement, steam heated by the exhaust gases may be used to heat the starting oil feedstock for the separation step (a) and then the steam may be reheated by the exhaust gases before being directed to a steam turbine, in order to optimise the steam turbine thermodynamics.
  • the temperature of the oil feedstock which can be reached using steam heating is partly limited by the wet steam temperature at normal steam pressures (at which efficient heat transfer can take place as water condenses out of the steam). To raise the oil temperature higher than about 300 0 C requires superheated steam.
  • the temperature of the exhaust gases immediately after they exit the gas turbine or diesel generator will generally be such that the gases can first be used to produce or re-heat high-pressure steam in a high-temperature section of a process heat recovery system.
  • the temperature of the exhaust gases is reduced to a temperature suitable for heating of the starting oil feedstock for separation by, for example, flashing.
  • Such temperatures may be greater than about 400°C, preferably greater than 425 0 C.
  • the use of cooler exhaust gases to heat the oil feed to the flashing vessel reduces the tendency for undesirable coking and fouling of the heating tubes to occur compared to use of a radiant-heat furnace.
  • the exhaust gases from the gas turbine or the diesel generator that have been partially cooled through giving up some of their heat to the starting feedstock oil still contain a significant amount of heat.
  • the temperature of the exhaust gas after heating of the starting feedstock may have been reduced to between about 250 and 350 0 C.
  • the temperature drop in the exhaust gas due to heating the starting feedstock oil is likely to be less than, about 50 0 C and could be as little as about 12 0 C.
  • the positioning of this heat removal step in the exhaust gas heat recovery arrangement is preferably done so as to keep the heat transfer surface requirements to a low level while utilising the higher temperature exhaust for heating high pressure steam.
  • the exhaust gases exiting the gas turbine or diesel generator may be directed via means for process heat recovery to a conventional boiler.
  • the exhaust gases contain oxygen (typically at levels of about 12 to about 14% by volume), they can be used to replace some or all of the air intake for the boiler.
  • the recovered process heat is then used for the fuel separation step (a).
  • the separation process in step (a) is controlled such that at least a portion of the light liquid stream is suitable to be fed directly to a gas turbine, if necessary after heating to achieve the required viscosity.
  • some or all of the light stream may be stored and/or further modified before it is used as a gas turbine fuel. Any portion of the light liquid stream which is not required for electricity generation according to the methods of the invention can be directed to or sold for other uses.
  • At least part of the light liquid stream is combusted in a gas turbine or a diesel generator to generate electricity.
  • at least part of the light liquid stream is combusted in a gas turbine. If some of the light liquid stream is combusted in a gas turbine, a further part of the light liquid stream may be combusted in a diesel generator.
  • the heavy stream may be combusted in a conventional steam boiler. It is highly preferred that any such boiler will be arranged in a re-powering configuration with the gas turbine or diesel generator used in step (b). Thus, all or part of the air intake of the boiler can be replaced by exhaust gas from the gas turbine and/or diesel generator used to combust the light liquid stream.
  • the heavy stream may be combusted in a modified heat recovery steam generator employing a duct firing system into which the exhaust gas from the gas turbine or diesel generator is directed.
  • a duct firing system into which the exhaust gas from the gas turbine or diesel generator is directed.
  • at least a portion of the heavy stream may be duct fired into the process heat recovery steam generator to ensure that the temperature therein is suitable for generating high-pressure steam to drive the steam turbine.
  • any flue gases generated when operating the methods of the invention may require treatment before they can be discharged to the atmosphere.
  • any discharged flue gases should be treated as necessary to meet any relevant emission standards.
  • the flue gases may require treatment to reduce levels of particulates, oxides of sulphur and/or oxides of nitrogen (NOx).
  • Any known flue gas treatment processes may be used together with the methods of the invention. If low sulphur light streams (e.g. containing less than about 0.2% by weight sulphur) are produced in the separation step (a), then it may be possible for the exhaust gases from the combustion of such streams in a gas turbine or diesel generator to be discharged directly to the atmosphere without the need for any treatment to reduce levels of sulphur oxides.
  • exhaust heat from the gas turbine or diesel generator is preferably used to provide heat for the separation step (a).
  • the separation step is integrated with the power generation step (b).
  • Figure 1 shows one scheme for the integration of atmospheric or vacuum flashing processing with a re-powering gas turbine exhaust heat recovery system.
  • Figure IA shows one scheme for the integration of atmospheric or vacuum flashing processing with a re-powering diesel exhaust heat recovery system.
  • Figure 2 shows a scheme for the integration of atmospheric flashing processing and solvent de-asphalting with a re-powering gas turbine exhaust recovery system.
  • Figure 2A shows a scheme for the integration of atmospheric flashing processing and solvent de- asphalting with a re-powering diesel exhaust recovery system.
  • Figure 3 shows a scheme for the integration of atmospheric and vacuum flashing of raw heavy oil feed and thermal cracking of the flash residue with a re-powering gas turbine combustion and exhaust heat recovery system.
  • Figure 4 shows one scheme for carrying out the method of the invention, referred to as radical re-powering.
  • Figure 4A shows a modification of the scheme shown in Figure 4 for carrying out ' the method of the invention, referred to as radical hybrid re-powering.
  • Figure 4B shows another modification of the scheme shown in Figure 4 for carrying out the method of the invention, referred to as radical diesel re-powering.
  • Figure 5 shows another scheme for carrying out the method of the invention, referred to as topping re-powering.
  • Figure 5 A shows a modification of the scheme shown in Figure 5 for carrying out the method of the invention, referred to as hybrid topping re-powering.
  • Figure 5B shows another modification of the scheme shown in Figure 5 for carrying out the method of the invention, referred to as diesel topping re-powering.
  • Figure 6 shows another scheme for carrying out the method of the invention, referred to as parallel hybrid re-powering.
  • Figure 6 A shows a modification of the scheme shown in Figure 6 for carrying out the method of the invention, referred to as parallel hybrid re-powering - diesel mode.
  • HP high pressure
  • LP low pressure
  • Figure 1 shows one scheme (referred to as limited processing) for the integration of atmospheric or vacuum flashing processing with a gas turbine exhaust heat recovery system.
  • the exhaust gases from the gas turbine (1) are directed to a heat recovery system (2).
  • the high- temperature (> 400°C) section of the heat- recovery system is utilised to produce or re-heat high-pressure steam (which can then be used to drive a steam turbine).
  • the reduced temperature exhaust is then used to heat the oil feed to the atmospheric or vacuum flashing vessel (3).
  • the oil feedstock is generally preheated to about 180-220°C by exchange of heat with the products from the separation process.
  • the heat from the exhaust gases then further heats the feedstock to a temperature suitable for flashing, for example about 350- 375°C.
  • a temperature suitable for flashing for example about 350- 375°C.
  • the starting oil feedstock is split into a number of streams, at least one of which is suitable for use as fuel for the gas turbine (1).
  • the heavy residue from the flashing is preferably sent immediately to an emulsification unit (4) where it is emulsified by mixing with a suitable quantity of water and a stabilising additive, to provide a stable emulsion fuel that may be easily stored until needed.
  • the aim of this processing is to make a significant quantity of gas turbine fuel such that the proportion of the mass of the gas turbine fuel to the mass of the heavy oil feedstock is greater than about 25%, preferably greater than about 33%.
  • Figure IA shows a modification of the scheme illustrated in Figure 1 in which a diesel generator (5) replaces the gas turbine.
  • the diesel generator exhaust gases are used to heat the feedstock for the separation process. After heating the feedstock, remaining heat in the exhaust gases may be used to generate steam (not shown).
  • Figure 2 shows a scheme (referred to as combined separation processing) for the integration of atmospheric flashing processing and solvent de-asphalting with a gas turbine exhaust recovery system.
  • the high-temperature section of the heat recovery system (2) is utilised to produce or re-heat high-pressure steam.
  • the reduced temperature exhaust is then used to further heat the oil feed to the flashing vessel (3).
  • the heavy residues from the flashing vessel are directed to process equipment for solvent de-asphalting (6).
  • the exhaust flow in the lower temperature section of the heat recovery system is then used to provide process heat to the solvent de-asphalting process equipment (6), either by direct heating of the oil flow or indirectly using freshly raised steam or by integration with the steam raising and re-heat system linked to the steam turbine (not shown).
  • the heavy precipitated asphalt stream is emulsified in an emulsification unit (4) before combustion. ' ,
  • the aim of this processing is to make a quantity of distillates plus gas turbine fuel that is greater than about 60% by weight of the quantity of the heavy oil feedstock.
  • Figure 2 A show a modification of the scheme illustrated in Figure 2 in which a diesel generator (5) replaces the gas turbine (1).
  • Figure 3 shows a scheme (referred to as combined thermal cracking processing) for the integration of atmospheric and vacuum flashing of a starting heavy oil feedstock with thermal cracking of the flash residue.
  • the hot residue from the flash vessel (3) is pumped to heater tubes (7) in the gas turbine exhaust heat exchanger (2) at a pressure of greater than 8 bara (800 kPaa), preferably greater than 10 bara (1000 kPaa), and in any event several bar (100 kPa) above the pressure of the gas turbine combustor.
  • Several tubes are used to give adequate residence time for thermal cracking to commence before discharging into a quench vessel (8) where water is injected to cool the mixture to below 375°C, preferably below 360°C, at which temperature cracking ceases to occur.
  • a soaker vessel may be used between the heater outlet and the quench vessel (8) to hold the hot residue for sufficient time to allow further cracking before entering the quench zone.
  • Medium pressure steam e.g. at pressure of between 8 bara (800 kPaa) and 20 bara (2000 kPaa) is injected into the tubes along with the residue to increase the velocity and turbulence in the heater tubes, as well as favourably modify the cracking reactions.
  • one of the tubes may be operated with no residue flow and only has a flow of steam. This allows any coke formed during cracking to be removed, with the resultant medium pressure superheated steam either joining the effluent from the other heater tubes in the soaker/quench vessel or being injected into the heater tubes carrying the residue stream.
  • the hot mixture passes from the quench zone into a high pressure separator (10) where the vapour is separated from the liquid.
  • the pressure of this vessel is preferably maintained at a sufficiently high differential to the gas turbine (1) combustor so as to drive the hot, separated gas stream into the combustor preferably without the use of a compressor.
  • This gas stream consists mainly of steam together with light hydrocarbons (mainly containing five or less carbon atoms) and some hydrogen sulphide that together provide a significant amount of the fuel requirement for the gas turbine (1).
  • the steam component of the gas is also heated to high temperature in the combustor and expands in the gas turbine expander section to enhance the power generated by the gas turbine (1).
  • the balance of the fuel to the gas turbine combustor is made up by blending some of the recovered light and medium streams from the separation processes.
  • the liquid from the high pressure separator (10) passes to a low pressure separator (11) operating near to atmospheric pressure where the vapour phase is condensed to give a light stream predominantly boiling below about 35O°C and a residual liquid stream that passes to a vacuum flash separation vessel (12).
  • the unused light and medium streams are available for export.
  • the residue from the vacuum flash vessel (12) is of very high viscosity and may be potentially unstable, if blended with lighter fractions, because of the increased proportion of high molecular weight asphaltenes and is immediately emulsified hot in an emulsif ⁇ cation unit (4), if necessary at an elevated pressure to avoid boiling the water being added, to produce a stable emulsion fuel that may be cooled, stored or burned.
  • the aim of this processing is to make a quantity of distillates plus gas turbine fuel that is greater than about 55% by weight of the quantity of the starting heavy oil feedstock.
  • the methods of the invention can utilise various different configurations for the gas turbine or diesel generator and the combustion of the heavy stream to generate steam.
  • a conventional power station boiler is totally replaced by a gas turbine (1) which is directly linked to a process and heat recovery steam generator (PHRSG) (13) that provides steam to an existing steam turbine (14).
  • PHSG process and heat recovery steam generator
  • the exhaust gases from the gas turbine (1) are fed to the PHRSG (13) where heat from the exhaust gases is used both to generate steam and to provide heat for the separation step (a), hi this configuration, the light liquid stream produced by the separation process is used as fuel for the gas turbine whilst the heavy stream (boiler fuel) which is unsuitable for gas turbine combustion is made into an emulsion and duct-fired into the heat recovery steam generator (13).
  • Such fuel may be injected at more than one point to bring the heating medium (i.e. fired gas turbine exhaust gas) to temperatures suitable for generating high-pressure steam to drive the steam turbine (14).
  • Flue gas from the PHRSG system has a low excess oxygen level (dependent on the ratio of fuel combusted in the gas turbine and through duct firing as well as the excess oxygen content of the exhaust gas exiting the gas turbine). This allows a high thermal efficiency as the total gas flow (and its heat content) leaving the heat recovery section is minimised. This also minimises the size of the flue gas clean up equipment as the volume of gas to be processed is at a minimum for the quantity of fuel being burned.
  • Radical Re-powering is preferably integrated with combined thermal cracking processing as this gives a relatively high proportion of fuel for the gas turbine.
  • the gas turbine would normally operate 24 hours a day to minimise thermal cycling of the integrated gas turbine-oil processing system while also maximising the benefit from the oil processing.
  • the heavy stream in the form of an emulsion fuel may be stored and the level of duct firing increased or decreased to follow load requirements for power or for added NOx control. Gas turbine capacity of up to twice the steam turbine may be added.
  • the flue gas clean-up unit (15) is sized to handle the full flue gas volume from the gas turbine. The level of sulphur to . be removed from the flue gas will vary according to the level of duct firing. Additional flexibility may be gained by installing two gas turbines in parallel discharging into a single integrated heat recovery steam generator and process heater (13).
  • FIG 4A shows a modification (referred to as Radical Hybrid Re-powering) of the scheme shown in Figure 4.
  • both a gas turbine (1) and a diesel generator (5) are used to combust portions of the light liquid stream.
  • This arrangement allows more flexibility as the diesel generator can run together with the gas turbine or may be shut down when the gas turbine operates.
  • the diesel generator is of sufficient size such that it can meet the entire heat requirement for the starting oil feedstock separation, such that the diesel generator can be run whenever the gas turbine is not operating so ensuring that the oil separation process can operate continuously.
  • This arrangement is preferably integrated with limited processing or combined separation processing.
  • FIG 4B shows another modification (referred to as Radical Diesel Re-powering) of the scheme shown in Figure 4.
  • only one or more diesel generators (5) are used to combust portions of the light liquid stream.
  • This arrangement allows flexibility as several diesel generators can be employed and only diesel generator capacity of sufficient size needs to be operated to meet the entire heat requirement for the starting oil feedstock separation, so ensuring that the oil separation process can operate continuously.
  • FIG. 5 shows an alternative embodiment for practising the methods of the invention (referred to as Topping).
  • This embodiment is preferably integrated with limited processing where relatively small additional gas turbine capacity is added.
  • a gas turbine (1) is used in combination with a conventional boiler (16) and a steam turbine (14).
  • the exhaust gas from the gas turbine (1) is first directed to means for process heat recovery (2), where it is used to provide processing heat for the feedstock fuel oil separation and, where opportunity exists, high-temperature steam re-heat capacity (not shown).
  • a duct fired process heat recovery steam generator in which some of the heavy stream is combusted may also be used.
  • the cooled exhaust gas is then used to replace some or all of the combustion air for a conventional boiler (16), and may replace the forced draft fan entirely.
  • the light liquid stream from the oil separation step is used to fuel the gas turbine (1) whilst at least a portion of the heavy stream is used (in the form of an emulsion fuel) to fuel the boiler (16).
  • One advantage of this embodiment is that it can be configured so that the excess oxygen level in the boiler flue gas is at a minimum. This allows the flue gas cleanup to be optimised, as there is no dilution of the gas stream contaminants that are to be removed.
  • FIG. 5 A shows a modification (referred to as Hybrid Topping Re-powering) of the scheme shown in Figure 5.
  • a diesel engine (5) is additionally included in the arrangement, which is preferably integrated with limited processing or combined separation processing.
  • the size of the diesel engine is such that it meets the entire heat requirement for the oil separation step.
  • the diesel engine and oil separation are run continuously and the balance of plant may operate, among others, in unfired mode where the diesel exhaust keeps the thermal plant at an elevated temperature which reduces thermal cycling effects and reduces the time taken to bring the boiler to power generation capability.
  • FIG 5B shows another modification (referred to as Diesel Topping Re-powering) of the scheme shown in Figure 5.
  • one or more diesel generators (5) replace the gas turbine in the re-powering configuration.
  • some of the diesel generator capacity and oil separation processing are run continuously and the balance of plant may operate, among others, in unfired mode where the diesel exhaust keeps the thermal plant at an elevated temperature which reduces thermal cycling effects and reduces the time taken to bring the boiler to power generation capability.
  • FIG. 6 shows an alternative embodiment for practising the method of the invention (referred to as Parallel Hybrid Re-powering).
  • This arrangement is preferably integrated with combined thermal cracking processing where any low sulphur components separated in the integrated oil processing are used in a gas turbine (1) with a process heat recovery steam generator (13) that discharges its exhaust without further clean up, as the flue gas meets environmental limits as a result of the fuel processing being configured to make suitably low-sulphur light liquid streams.
  • Any higher sulphur gas turbine fuel and the heavy streams are used by the rest of the system that may consist of an unmodified conventional boiler or one of the re- powering configurations discussed previously such as Radical Re-powering or Topping Re-powering.
  • Figure 6A shows a modification (referred to as Parallel Hybrid Re-powering - Diesel Mode) of the scheme shown in Figure 6.
  • the gas turbine is replaced with a diesel generator (5).
  • This arrangement is preferably integrated with limited processing or combined separation processing, and the size of the diesel engine is preferably such that it meets the entire heat requirement for the fuel oil separation. In this configuration, the balance of plant may be operated independently drawing on the fuels made by the integrated heavy oil separation.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Engine Equipment That Uses Special Cycles (AREA)
  • Liquid Carbonaceous Fuels (AREA)

Abstract

L'invention concerne des procédés de production d'énergie électrique à partir de réserves d'huile lourde. Les méthodes consistent: à séparer une réserve d'huile liquide de mise en route en au moins un écoulement liquide et un écoulement d'huile lourde; à faire brûler au moins une partie de l'huile légère dans une turbine à gaz ou une génératrice entraînée par un moteur diesel pour produire de l'électricité; à combiner au moins une partie de l'huile lourde avec de l'eau et un additif de stabilisation pour former une émulsion combustible; et à faire brûler au moins une partie de l'émulsion combustible pour obtenir de la vapeur alimentant une turbine à vapeur de production d'électricité.
PCT/GB2007/002259 2006-06-16 2007-06-15 Procédé de production d'énergie électrique WO2007144661A2 (fr)

Applications Claiming Priority (2)

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GB0612014.1 2006-06-16
GB0612014A GB0612014D0 (en) 2006-06-16 2006-06-16 Method

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WO2007144661A2 true WO2007144661A2 (fr) 2007-12-21
WO2007144661A3 WO2007144661A3 (fr) 2009-01-29

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011131706A1 (fr) 2010-04-20 2011-10-27 Shell Internationale Research Maatschappij B.V. Procédé pour faire fonctionner une turbine à gaz
WO2012039890A1 (fr) * 2010-09-20 2012-03-29 Exxonmobil Chemical Patents Inc. Procédé et appareil pour la coproduction d'oléfines et d'énergie électrique
WO2022176130A1 (fr) * 2021-02-18 2022-08-25 日揮グローバル株式会社 Centrale électrique et procédé d'exploitation d'une centrale électrique

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH1182991A (ja) * 1997-09-03 1999-03-26 Mitsubishi Heavy Ind Ltd 発電用石炭の乾燥・パージ方法及びその装置
EP0955455A1 (fr) * 1996-12-26 1999-11-10 Mitsubishi Heavy Industries, Ltd. Production d'electricite et installations associees
EP1083301A2 (fr) * 1999-09-08 2001-03-14 Mitsubishi Heavy Industries, Ltd. Méthode pour la génération de puissance à haut rendement
WO2003016439A1 (fr) * 2001-08-13 2003-02-27 Clean Fuels Technology, Inc. Carburant sous forme d'emulsion eau dans l'huile

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0955455A1 (fr) * 1996-12-26 1999-11-10 Mitsubishi Heavy Industries, Ltd. Production d'electricite et installations associees
JPH1182991A (ja) * 1997-09-03 1999-03-26 Mitsubishi Heavy Ind Ltd 発電用石炭の乾燥・パージ方法及びその装置
EP1083301A2 (fr) * 1999-09-08 2001-03-14 Mitsubishi Heavy Industries, Ltd. Méthode pour la génération de puissance à haut rendement
WO2003016439A1 (fr) * 2001-08-13 2003-02-27 Clean Fuels Technology, Inc. Carburant sous forme d'emulsion eau dans l'huile

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011131706A1 (fr) 2010-04-20 2011-10-27 Shell Internationale Research Maatschappij B.V. Procédé pour faire fonctionner une turbine à gaz
WO2012039890A1 (fr) * 2010-09-20 2012-03-29 Exxonmobil Chemical Patents Inc. Procédé et appareil pour la coproduction d'oléfines et d'énergie électrique
US9296955B2 (en) 2010-09-20 2016-03-29 Exxonmobil Chemical Patents Inc. Process and apparatus for co-production of olefins and electric power
WO2022176130A1 (fr) * 2021-02-18 2022-08-25 日揮グローバル株式会社 Centrale électrique et procédé d'exploitation d'une centrale électrique

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WO2007144661A3 (fr) 2009-01-29

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