RU2772306C1 - Installation for generating mechanical energy using a combined energy cycle - Google Patents

Abstract

FIELD: power engineering.

SUBSTANCE: scope of the present invention relates to the field of technology related to the generation of mechanical energy for application and conversion into other types of energy. An installation for generating mechanical energy using a combined energy cycle contains at least: means for implementing a closed or semi-closed regenerative component of the Brayton cycle, in which water is used as a heat transfer medium, means for implementing at least one Rankine cycle, which makes up the main Rankine cycle, interconnected with the regenerative component of the Brayton cycle, and a heat pump (UAX), which forms a closed circuit that regenerates the regenerative component Brayton cycle. A method for generating energy using the specified installation is also presented.

EFFECT: invention makes it possible to effectively use the heat released by the component of the Brayton cycle, exactly at the point of the cycle where the temperature is the lowest.

32 cl, 6 dwg

Description

FIELD OF TECHNOLOGY

The scope of the present invention relates to the field of technology related to the generation of mechanical energy for use and conversion into other types of energy.

BACKGROUND OF THE INVENTION

Currently, the so-called "combined cycles" are one of the most efficient and environmentally friendly technologies available for power generation. The combined cycle is a method of generating energy by combining two related thermodynamic cycles to improve performance.

In the prior art of combined cycles for generating mechanical energy and its possible conversion into other types of energy, there is a need to improve efficiency and reduce greenhouse gas emissions to the atmosphere.

One combined cycle plant is a gas turbine operating in an open Brayton cycle in which hot exhaust gases pass through a waste heat boiler where a flow is generated that is applied to the turbine performing additional mechanical work after an independent Rankine cycle.

The most common combined cycle power plants operate with gas turbines that take in outside air, which, after pressurizing the compressor, passes into the combustion chamber where the fuel is burned. The exhaust gases from this exit the combustion chamber at high temperature with excess air being the Brayton open cycle heat transfer medium which expands in the gas turbine, generating mechanical work. Finally, the turbine gases leave the boiler and are released into the atmosphere through the chimney.

The fact that the compressor draws in air from the outside and the combustion gases are eventually vented to the atmosphere without being recycled means that these are open Brayton cycles, since there is a mutual exchange of matter with the atmosphere.

Therefore, and despite their simplicity, these open cycles have the disadvantage that they involve the emission of pollutant gases when the combustion products are eventually released into the atmosphere. These pollutant gases are mainly CO2 and NOx (always provided the fuel is sulfur-free). The proportion of CO2 emitted during combustion depends directly on the type of fuel being burned. Natural gas is currently the most widely used fuel in the gas turbine industry because, among other things, the methane contained in this fuel is the hydrocarbon that produces the least amount of CO2 per unit of work produced.

In addition, NOx production increases significantly with increasing combustion temperature. Obviously, this creates a conflict of interest with a trade-off between efficiency and environmental impact, because according to the principles of thermodynamics, an increase in combustion temperature increases productivity, but on the other hand it leads to an increase in NO _x emissions.

The ultimate goal, which would overcome the shortcomings of the prior art, is to develop a cycle that mainly produces mechanical energy, which does not result in the emission of any greenhouse gases into the atmosphere, and which gives better performance than currently obtained in other traditional combined cycles.

The present invention relates to a plant for performing a combined cycle process for generating mechanical power, which uses water as a heat transfer medium, and which is specially designed to operate in a closed cycle, or to perform a process based on internal oxygen combustion, which has at least one Rankine cycle, which works in an integrated manner with a variant of the Brayton cycle, which is restored using a heat pump, which exchanges this thermal energy (there is no mutual exchange of matter between the Brayton cycle and the heat pump), and so that by combining the two indicated components of the cycles, mechanical energy generate without the need to emit greenhouse gases into the atmosphere.

One alternative to eliminate the emission of polluting gases into the atmosphere is to use combined cycles, which operate as closed cycles. In other words, in these cycles, the heat transfer medium is recirculated and does not need to be replenished, nor does it come into contact with the atmosphere. However, wherever the heat source of the cycle is energy from internal combustion, certain chemicals (fuel and combustion aid) must be constantly added, while products generated by the chemical combustion reaction must be removed from the cycle. This creates important economic, technical and environmental problems, especially with regard to the continuous separation of combustion products in the gas phase, which acts as a heat transfer medium. Another disadvantage is that since air is not used as a combustion support medium, closed circuits require pure oxygen to carry out the combustion process and therefore depend on some auxiliary process to provide it.

An effective way to increase the efficiency of the Brayton cycle is "regeneration", whereby part of the heating of the cycle is performed using a heat source that is internal to the cycle itself.

Through "regeneration", improved performance for the cycle is achieved, since the amount of external heat that must be supplied to the cycle is reduced, and thus the amount of waste heat released by the cycle to the external environment is reduced.

The term "Brighton regenerative cycle" refers to a Brayton cycle in which part of the heat generated by the hot gases behind the turbine is recovered and transferred, using a heat exchanger, to the compressed gases before they enter the combustion chamber. However, this regeneration method is not the only one, since it is also possible to "regenerate" the Brayton cycle using any other method that can recover heat from some part of the cycle to be introduced back into the process.

One of the innovative aspects of this invention is that it contains the means necessary to implement a regenerated Brayton cycle using a "heat pump" connected to one or more Rankine cycles, which gives rise to a combined cycle plant with unusual characteristics.

In thermodynamics, a "heat pump" is defined as any refrigeration machine that takes thermal energy from one body and transfers it to another, which has a higher temperature, due to some amount of energy supplied from the outside (usually in the form of mechanical work from compression). For all purposes, a chiller may be considered to be the same as a heat pump, and the two terms are used without distinction or with regard to the intended application.

At the industrial level, there are two types of chillers or heat pumps, depending on the type of technology they use: compression chillers and absorption chillers. These two types of machines (compression or absorption) have in common that they all have a condenser (high temperature source) and an evaporator (low temperature source) separated by an expansion device. However, they differ in the way and type of energy used to make the low temperature and high temperature sources operate at different pressures.

Compression refrigeration machines use a gas compressor that consumes mechanical work taken from outside, while absorption machines require essentially just a supply from an external heat source to operate, and these machines are based on the physico-chemical principle of absorption / desorption of gas in a liquid. .

Traditional "absorption" machines can do without a compressor because the "absorber/generator" system, without the need for mechanical means, is responsible for generating the required pressure difference, making the absorber and evaporator operate at a lower pressure than the generator and condenser.

Instead of requiring compressor compression work to operate, absorption machines require additional heat to perform the "desorption" (evaporation of dissolved gas) operation. Ultimately, this additional amount of heat is removed when the reverse "absorption" process occurs. This additional heat loss is the reason why, comparatively speaking, absorption machines lose and require more energy to operate than compression machines, so that their energy efficiency is always relatively low. However, absorption machines still have the advantage that, apart from the solution pump, they require little or no mechanical work to operate.

The applicability of a "heat pump" to assist regeneration in a combined cycle system is extremely limited, on the one hand, by a number of inevitable thermodynamic limitations, and on the other hand, by the specific requirements necessary for its operation. In other words, the Brayton cycle cannot be regenerated using just some arbitrary heat pump.

In order for a particular heat pump to be useful for the "regeneration" of the Brayton cycle, as proposed in this document, it must meet the following requirements:

- the "low temperature source" of the heat pump must operate at temperatures close to the condensing temperatures of water vapor at atmospheric pressure;

- the temperature difference between the low-temperature and high-temperature sources must be significant (several tens of degrees Celsius) in order to regenerate steam at a pressure significantly higher than the pressure at which it was previously condensed;

- the energy of mechanical compression must also be taken from the Brayton cycle, which is being regenerated, and returned to it;

- the productivity of the refrigeration cycle must be substantially high in order for such a method of the regenerating part of the combined cycle to be appropriate.

The combined cycle plant that is the subject of this invention offers, on the one hand, greater efficiency than traditional combined cycles and, on the other hand, a natural capture of CO ₂ (carbon dioxide) when any of the heat sources supplying heat in the combined cycle, consists of a combustion chamber. The installation according to the present invention and the method performed with it, indirectly provide a system for separating and capturing carbon dioxide.

The combined cycle is meant to “naturally capture CO ₂ ” when this combustion gas is obtained at a single point in the cycle, concentrated and sequestered (in liquid or gaseous form) without the need for any additional process other than the normal operation of the cycle itself to generate useful energy. When fuels are used as an energy source, the very operation of the plant separates and isolates pollutant gases and prevents them from coming into contact with the atmosphere. On the other hand, when water is generated as a combustion product, it is, on the other hand, removed from the combined cycle in liquid phase and at ambient pressure.

Traditional combined cycles use a separate heat transfer medium in each constituent cycle (Brighton and Rankine) and, more specifically, their Brayton cycle exchanges matter and energy with the atmosphere.

On the other hand, the constituent Brayton cycle and the constituent main Rankine cycle, which include this combined cycle, work in conjunction, producing an exchange of matter (while both use water as a common heat transfer medium) and energy, so as to constitute an inherently single cycle for generating mechanical energy and with special features.

One feature of this combined cycle is that, except for the inevitable "direct losses", heat is removed to the external environment only through a single heat sink, and therefore better performance is obtained than in other traditional combined cycles.

Given that the component Brayton and Rankine cycles that form the combined cycle of this invention have specific features that distinguish them from these thermodynamic cycles in certain significant aspects, the terms "Brighton cycle" and "Rankine cycle", when referring to sections that include a combined cycle as a whole are not strictly true because they differ from these cycles in certain fundamental respects (for example, Brayton cycles, by definition, do not work with a condensable liquid). However, it is true that the combined cycle of this invention consists of variations or modifications of the two cycles, Brighton and Rankin, and they actually work in conjunction. That is why in this document, these modified Brayton and Rankin cycles are always referred to with the word "constituent" in order to prevent confusion and facilitate the perception and identification of the components to which reference is made.

DEFINITIONS

UAX: Absorber block for heat exchange. It is a system that acts as a "heat pump" to help regenerate this combined energy cycle. UAX, as an independent working unit, is identified by a number (200). It is used to regenerate the constituent Brayton cycle. UAX (200), although it does not reciprocate with the combined energy cycle, works in "symbiosis" with it and is a mandatory system for combined cycle operation to generate mechanical energy. UAX is the main component of the installation of the present invention, which works with ammonia and water.

Concentrated Solution: This is a solution of ammonia in water that comes out of the absorber.

Diluted Solution: This is the ammonia/water solution that comes out of the generator (201).

Intermediate Solution: This is the solution of ammonia in water that exits the generator (202) and that enters the generator (201).

Combined cycle: Unless otherwise indicated, the term "Combined cycle" refers to the cycle that is the subject of this invention, the purpose of which is to obtain mechanical energy from thermal energy. In this description, the terms "Combined Cycle", "Power Cycle" and "Combined Power Cycle" are used without distinction. The term "conventional combined cycle" is used herein to refer to any possible combined cycle known from the prior art.

Regenerative cycle: This is a cycle with a system of heat exchangers to "regenerate" it, in the sense that some heating of the cycle is done using a heat source internal to the cycle itself.

Brayton constituent cycle: This is the part of the energy cycle of this invention, which is regenerated by the heat pump UAX (200). The functioning of this part of the energy cycle is based on a modification of the Brayton cycle, which in this invention has such specific special features as the use of condensable fluid (water), operation in conjunction with the Rankine cycle and regeneration by means of a heat pump UAX (200).

Constituent Main Rankine Cycle: This is the part of the power cycle of this invention that is driven by the feed pump (119) and the HPT turbine (122). The functioning of this part of the energy cycle is based on the Rankin cycle, although in this invention the "major Rankin cycle" has such specific special features as interlocking with the "constituent Brayton cycle" so that they have certain common elements. The constituent main Rankine cycle is the main part of the energy cycle.

Secondary Rankine Cycle: This is a subsidiary Rankine cycle: in other words, it is not the main system of the energy cycle. In combined cycle configurations that have a "Secondary Rankine Cycle", its capacitor (128) always performs the primary "heat sink" function. The "secondary Rankine cycle" is characterized by having its own LPT turbine (127) and always operating at a lower pressure than the constituent main Rankine cycle.

Open cycle: This is a cycle in which the heat transfer medium is not recycled, but must be constantly renewed. In open loops, there is at least one point where fluid enters from the outside and another where fluid exits the loop into the outside.

Closed loop: A loop in which no heat transfer medium enters or exits, in which the supply of external heat always occurs through heat exchangers, so there is no mutual exchange of fluid material in the loop with the external environment. A combined energy cycle is closed when it does not contain a combustion chamber that provides it with energy.

External Combustion Cycle: This is a closed cycle where the source of heat supply is the combustion process occurring outside the cycle.

Internal combustion cycle: This is a closed cycle where the source of heat supply is a combustion process in which the products of a chemical reaction form or form part of the heat transfer medium.

Oxygen combustion: This is a combustion process that uses not air but pure oxygen diluted in the heat transfer medium itself (steam in this invention) as the combustion support medium.

Semi-closed cycle: In this invention, this term is used for a cycle that simultaneously provides internal combustion and combustion in oxygen and in which, in addition, the heat transfer medium is recycled when the products of combustion have been removed from it.

Efficiency: The Efficiency (Coefficient of Performance) of a "heat pump" is defined as the ratio or quotient obtained by dividing the usable thermal energy transferred by the energy added to achieve it. In other words, efficiency is a factor that determines the performance of any chiller. The concept of efficiency varies depending on whether the machine is compressor (in which the added energy is the mechanical work consumed by the compressor) or absorption (in which the added energy is mainly heat supplied to the generator).

Installation: Mechanical energy generator device consisting of a combined energy cycle and a heat pump UAX (200).

Heat Exchange Element: Any of the sides forming a heat exchanger, regardless of whether it receives heat or gives it away. Any heat exchanger consists of at least two elements. In this invention, the term "element" followed by a number that explicitly identifies it is used for brevity. In this invention, any heat exchanger is identified by indicating the numbers of two or more of its constituent "elements".

Coil: A heat exchange element consisting of a set of pipes in any type of configuration. In this invention, this term is used to refer to an exchanger element that operates at a higher pressure. Functioning under no circumstances can be associated with the shape of the heat exchanger element, which is so called.

Heat Exchanger Body Side: This term is used in this document to refer to an exchanger element which operates at a lower pressure and which contains within it a heat exchange element operating at a higher pressure.

Condensation exchanger: This is a heat exchanger in which the condensation (partial or complete) of the water vapor circulating through the "body side" element takes place. This heat of condensation is transferred to one or more coils or exchanger elements to raise the temperature of the fluid circulating through them.

Heat sink: In this invention, the term "heat sink" is used to refer to the heat exchanger element through which the combined cycle releases unused heat outside the cycle. In a combined energy cycle, the "heat sink" always consists of an element (128) that condenses the steam in the final part or after the recovery channel of the RKK (103). When a secondary Rankine cycle is applied in this position to perform this function, this auxiliary cycle will always have a condensation end element, designated (128), to clearly indicate that it is the only element through which heat is transferred outside the cycle.

Direct Loss: This term refers to the inevitable irreversible phenomena and heat loss due to heat transfer, convection and radiation in any component caused by the simple fact that it is at a higher temperature than its surroundings. Given that direct losses are inevitable in any real cycle, even when they are not explicitly mentioned in this description, they are considered obvious.

In this description, although such an action would not be accepted as true in thermodynamics, the latent heat contained in the combustion products produced in the combined cycle is also considered "direct losses", since in reality they appear at such a low temperature - liquid water with one side and CO ₂ from element (107) - that it is insignificant or can be considered negligible for practical purposes.

Heat transfer medium: This is a fluid medium that contains, circulates and transports energy transferred in different elements that form a thermodynamic cycle.

Cogeneration: In this description, cogeneration is understood to mean an optional procedure by which, in addition to mechanical energy, an additional amount of thermal energy is obtained, which is useful for any type of process outside the energy cycle itself. In this description, it is assumed for all purposes that the heat released by a combined cycle to the external environment as a result of "cogeneration" is always useful heat and never represents energy loss from the cycle, since the plant is considered to be designed to account for this heat recovery. energy from the energy cycle: this is carried out in accordance with specific requirements and taking into account the temperature conditions imposed by the external consumption system for which the heat is intended.

Useful energy: This term refers to the sum of the heat to be used outside of the cycle, as "cogeneration", and the useful mechanical work produced by the energy cycle.

Transfer shaft: The transfer shaft (130) consists of an assembly of mechanical elements with which the energy cycle machines and the UAX heat pump receive or release mechanical energy.

Physically, the transfer shaft does not need to consist of a conventional mechanical shaft to which all the cycle's turbomachines are connected, since it is also feasible to connect each compressor to an independent motor, with each turbine connected to its respective electrical generator. However, using this understanding of the transfer shaft makes it easier to understand, since it is considered that the useful mechanical work of the combined cycle is obtained from the transfer shaft (130) as a result of the summation of all the mechanical work of all the machines that compose it (taking into account their signs).

Industrial Pure Oxygen: The term "industrial pure oxygen" in this specification is used to refer to this gas when, according to its state of supply, it meets international standards as "industrial grade pure oxygen". It is considered obvious that, although undesirable, traces of impurities will always accompany oxygen used as a combustion support agent for industrial applications.

Supercritical pressure and temperature: These are pressure and temperature conditions that are above the critical point for a given substance. The critical point is the point at which the vapor and liquid densities are the same.

Ambient pressure: The term "ambient pressure" is used in this document to refer to the pressure range corresponding to the saturation pressure of water vapor between 80°C and 120°C. That is, the ambient pressure is considered to be in the pressure range of 0.5 bar to 2.0 bar, approximately.

Bar: absolute pressure bar

DESCRIPTION OF THE DRAWINGS

This description contains five figures. The first four are schematic representations of different configurations or design versions of the presented combined energy cycle. Finally, the fifth figure is a schematic representation of the configuration of the "Heat Exchange Absorber Unit" (UAX), which performs the main function of assisting the energy cycle as a "heat pump".

In FIG. 1 shows a conceptual design version of the "Essential Combined Cycle" according to configuration 1, which has the elements indispensable for the combined cycle to be able to operate using a heat pump (UAX) according to this invention. Whatever the design configuration of the energy cycle, it contains all the main elements presented in this fig. 1, on the basis of which these components are called "basic".

In FIG. 2 schematically shows a design version of a combined cycle plant for generating mechanical power according to configuration 2 of the present invention, which, in addition to the main cycle equipment (shown in Fig. 1), contains elements that provide increased efficiency for the combined cycle, with the characteristic feature, that it operates at a pressure above atmospheric pressure in the entire recovery channel (RCC) (103). At the end section of the RKK (103), steam is generated in a secondary Rankine cycle, which uses its own heat transfer medium, independent of the rest of the power cycle. This configuration assumes that there is a terminal section of the channel in the RSC (103) where the water vapor circulating in it is partially condensed to generate steam in the secondary Rankine cycle.

In FIG. 3 schematically shows a design version of a combined cycle plant for generating mechanical power according to configuration 3 of the present invention, which, in addition to the main cycle equipment (shown in Fig. 1), contains elements that provide increased efficiency for the combined cycle, with the characteristic feature, that in this combined cycle configuration there is no condensation in the recovery duct (RCC) (103), but instead there is a separate duct (105) where the water vapor circulating through it is partially condensed. Between these two channels (103) and (105), respectively, there is a fan (104), which draws in gases and exhaust steam from the RAC (103) and raises the pressure in the section of the channel (105), which accommodates at least one part of the evaporator ( 125) for the secondary Rankine cycle, which uses its own heat transfer medium independent of the rest of the power cycle.

In FIG. 4 schematically shows a design version of a combined cycle plant for generating mechanical power according to configuration 4 of the present invention using UAX (200), which, in addition to the main cycle equipment (shown in Fig. 1), includes elements that provide increased efficiency to the combined cycle, which due to its simplicity is more suitable when the plant is designed to operate in a closed cycle or when only hydrogen is used as fuel. That is, when there is no CO ₂ in the energy cycle.

This combined cycle configuration has the characteristic that it uses part of the water vapor flow circulating through the RAC (103) to be sent directly to the turbine (127) of the secondary Rankine cycle, which uses the same heat transfer medium as the rest of the energy cycle. In addition, the condensed water obtained from the condenser (128) is also used directly as feed water for the rest of the combined cycle. This means that in this version of the energy cycle, the secondary Rankine cycle does not form an independent cycle, but is integrated into it, forming a single cycle.

In FIG. 5 shows a schematic representation of the configuration of a "Heat Exchange Absorber Unit" (UAX) which performs the "heat pump" function required for the operation of the combined cycle of this invention.

In FIG. 6 schematically shows a design version of a combined cycle plant for generating mechanical power according to configuration 5 of the present invention using UAX (200), which includes all cycle equipment in any of its configurations. It provides either closed-loop or semi-closed-loop operation using any type of fuel that can be used in other configurations.

Configuration 5 has the same elements as configuration 3 plus superheater (136) and turbine (137). Configuration 5 differs from configuration 3 in that one element (112) has two additional outlet streams (one with steam and the other with preheated feed water). Another difference is that in configuration 5 one compressor (115) has an additional compression stage compared to configuration 3.

DESCRIPTION OF THE INVENTION

This invention relates to the installation according to claim 1 of the claims, as well as to a method for generating energy according to the subject matter of the invention associated with the method. Specific plant and method embodiments are described in the respective dependent claims.

This invention relates to a plant for generating power using a combined energy cycle, which contains at least:

- means for realizing a closed or semi-closed regenerative component of the Brayton cycle, in which water is used as a heat transfer medium,

- means for realizing at least one Rankine cycle constituting the main Rankine cycle interconnected with the regenerative constituent Brayton cycle, and

- a heat pump (UAX) that forms a closed circuit that regenerates the constituent Brayton cycle.

The power generation plant also contains a main heat source (101) selected from:

- heat exchanger and

- combustion chambers with combustion in oxygen,

such that in said main heat source (101) the fluxes from two cycles constituting the Brayton and constituting the main Rankine converge together.

According to specific additional embodiments of the present invention, when the combined energy cycle is semi-closed, with combustion in oxygen and capture of CO ₂ , it contains at least one internal combustion chamber, through which it receives energy from the outside.

According to specific additional embodiments of the present invention, when the combined energy cycle is closed, it does not have any combustion chambers and contains at least one heat exchanger, through which it receives energy from the outside, and does not have an internal combustion chamber.

For any of the above embodiments, the installation also comprises:

- element (107), which may be:

- a regeneration condenser (107), through which the unit transfers energy to the low temperature source (201) of the UAX heat pump, which condenses in one simple step, or

- a CO ₂ liquefier, which receives work from the transfer shaft (130) and condenses the gases in several stages and only transfers the heat generated in the successive compression stages of this CO ₂ liquefier to the low temperature source (201) UAX,

- a reboiler (113) with which heat is returned to the energy cycle from a high-temperature source (210) of the heat pump UAX,

- a pump (111) of the regeneration condensate, which drives the condensate obtained in the lower part of the element (107) and makes it flow to the reboiler (113),

- recovery channel (RCC) (103), in which water vapor is generated,

- at least two turbines, one of which is a turbine (122) high pressure (HPT), which directs steam to the main source (101) of heat, and the other turbine (102) is a high temperature (HTT), which directs steam to the recovery RKK channel (103),

- at least one common transmission shaft (130), from which the useful mechanical energy of the cycle is obtained,

- a system that performs the function of heat removal by means of steam condensation in the lower part of the RKK (103) or after it,

- condensate return pump (109),

- feed pump (119) for the constituent main Rankine cycle,

- steam generator for the constituent main Rankine cycle, consisting of:

- economizer coils (120),

- evaporators and superheaters for steam (121) located inside the RKK (103),

- one condensing element (106) for heat exchange before the inlet of steam and gases into the element (107), which gives off heat to the condensate return heater (110),

- one condensing element (114) heat exchange, provided at the outlet of the reboiler (113), which gives off heat to

- a bypass line that connects the constituent Brayton cycle to the constituent main Rankine cycle, located on the element (112) selected from:

- a heater (112) for supplying water to the reboiler itself (113),

- and a recovery exchanger (112) which, in addition to preheating the feed water for the reboiler (113) itself, can heat the feed water for the pump (119) and generate steam that can be sent to the compressor (115) and/or turbine heater (137 ) after increasing its temperature in the superheater (136)

between the discharge port of the regeneration condensate pump (111) and the suction port of the feed pump (119).

In the case where the component Brayton cycle is semi-closed, uses oxygen combustion, and in the case of carbon fuels, the plant contains:

- an outlet for CO ₂ produced by combustion, located in the regeneration condenser (107) in a gaseous or liquid state, if the regeneration condenser (107) is a liquefaction plant, and

- outlet for liquid water produced by combustion in the condensate return line.

In the case where the power generation plant is a closed Brayton cycle, or in the case where it uses only hydrogen as fuel, the heat removal may consist of a secondary Rankine cycle that uses the same fluid as the rest of the power plant. cycle, and which is interconnected with the installation by means of the RKK (103) and the condensate return pump (109).

In any of the previous embodiments, the installation for generating energy may contain, in addition to the main source (101) of heat, another auxiliary source (132) of heat, which provides additional heat to the energy cycle from the outside (this may be an exchanger or a pressurized combustion chamber), located between the terminal superheater (121) and the HPT turbine (122).

In any of the previous embodiments, the power generation plant may further comprise one compressor (115) or several steam compressors (117) connected in series, which are located at the steam outlet of the exchanger element (114) and before the steam inlet of the main source ( 101) heat.

In any of the previous embodiments, the power generation plant may further comprise a refrigeration exchanger (116/118) for steam between the serially connected compressors (115) and (117).

In any of the previous embodiments, the power generation plant may further comprise, in the condensate line exiting the bottom of the condensate exchanger element (114), a return line to the reboiler (113).

In any of the previous embodiments, the power generation plant may further comprise an additional exchanger provided at the steam inlet of the recovery duct (103) to generate heat that can be used outside of the plant, applicable for, among other things, cogeneration applications using coil (133) heat exchanger.

In any of the previous embodiments, the power generation plant may further comprise a cogeneration heat exchanger element (133) provided within the recovery duct (103) from which it extracts useful thermal energy that can be destined for external use in any type of industrial application.

In any of the previous embodiments, the power generation plant may further comprise:

- a fan (104), which takes the outlet vapors from the recovery channel of the RKK (103) and compresses them to be sent to the element (105) of the condensation exchanger, which contains at least one component section of the evaporator (125) of an independent secondary Rankine cycle.

In the embodiment mentioned in the previous paragraph, the power generation plant may further comprise:

- a heat exchanger (108/124), in which the condensate from the channel (105) is cooled on the housing side (108) and inside which the economizer (124) of the independent secondary Rankine cycle is located.

In any of the previous embodiments, the installation heat pump UAX (200) contains:

- the main generator (201) of gaseous ammonia, acting as a low-temperature source, which exchanges heat only with the element (107),

- a secondary generator (202) which receives the ammonia solution from the absorber (210) and sends the ammonia vapor to some compressors (203), while the remaining ammonia solution is sent to the main generator (201),

- at least two ammonia compressors (203), connected in series, with intermediate cooling, which receive ammonia from the main (201) and secondary generators (202),

- a compressed ammonia condenser (207) which receives the ammonia compressed and cooled in the supercritical ammonia evaporator (209) and transfers heat to the secondary generator (202),

- evaporator (209) of supercritical ammonia,

- a pump (208) for ammonia condensate from the compressed ammonia condenser (207), which pumps it into the ammonia evaporator (209), where ammonia vapor is produced at supercritical pressure,

- an ammonia absorber (210) which receives steam from the evaporator (209) for supercritical ammonia and dissolves it in the aqueous phase, and

- a transfer pump (215) which pumps the diluted ammonia solution from the main generator (201) to the absorber (210).

Heat pump UAX (200) may additionally contain:

- a heat exchanger (213/214) between the diluted ammonia solution from the main generator (201) and the concentrated ammonia solution from the absorber (210),

- a coil (211) placed inside the ammonia evaporator (209), which uses the heat contained in the concentrated ammonia solution from the absorber (210) to produce supercritical ammonia,

- a cooling coil (206) for the compressed ammonia from the compressors (203) which provides heat to the supercritical ammonia evaporator (209).

This invention also relates to a combined cycle power generation method implemented using the plant defined above.

The defined method includes:

- the implementation of a component Brayton cycle, closed or based on combustion in oxygen, regenerated by a heat pump (UAX), which uses water as a heat transfer medium and which produces mechanical energy in a high-temperature turbine BTT (102),

- the implementation of the component Rankine cycle, interconnected with the above Brayton cycle, which exchanges matter and energy with it, and in which both water is used as a common heat transfer medium, and produces mechanical energy on the HPT turbine (122),

- the use of a UAX heat pump (200) which exchanges energy with the constituent Brayton cycle in order to regenerate it and consume mechanical energy in certain compressors (203).

In the process of the present invention, all the water vapor of the cycle can be completely condensed in the element (107) where CO ₂ is released into the gas phase when fuels other than hydrogen are used in the cycle.

According to specific embodiments of the method, the water vapor that circulates through the element (107) is completely condensed due to the heat that is transferred to the low temperature source UAX (200), leaving only liquid or gaseous CO ₂ as a residue, as appropriate, in case the cycle fuels other than hydrogen are used.

In the method according to the present invention, the regeneration of the Brayton component cycle can be carried out by the action of the UAX (200) heat pump recirculating the condensation heat of the steam at the temperature of the low temperature source, to then return it to the cycle through the high temperature source to regenerate water vapor at higher pressure and temperature. than those at which it was previously condensed.

According to specific embodiments, the method includes:

- condensation of water vapor at ambient pressure in the element (107), which transfers the received heat to the low-temperature source (201) of the heat pump UAX (200)

- recovery of water vapor in the reboiler (113) at a higher pressure than that at which it was condensed in the element (107), using the heat provided by the high temperature source (210) of the heat pump UAX (200).

According to specific additional embodiments, the method includes the use of an auxiliary heat source (132), which provides additional heat to the power cycle from the outside, located between the superheater (121) and the HPT turbine (122).

According to specific additional embodiments, the method includes the use of a single heat sink through which the cycle releases unused heat to the outside. The function of this heat sink can be performed by an independent secondary Rankine cycle.

According to specific additional embodiments, the method includes the use of a recovery channel RKK (103), which uses the remaining heat from the outlet of the turbine WTT (102) to generate superheated steam component of the main Rankine cycle.

According to specific additional embodiments, the method includes the implementation of a combined cycle with combustion in oxygen and the use of liquid or gaseous fuels with the general formula C _x H _y O _z in pure or mixed form, where x, y and z take values corresponding to real chemical compounds, which can burn in the presence of oxygen. Preferred fuels are hydrocarbons that are gaseous or have a low boiling point, such as, for example, methane, ethane, propane, or mixtures thereof, such as purified natural gas. Useful fuels are also simple alcohols such as methanol or ethanol. CO (carbon monoxide) is the only non-hydrogen-containing substance that is usable as a fuel in combined energy cycle combustion chambers.

According to specific additional embodiments, the method includes condensing part of the water vapor from the recovery channel (103) using a heat sink and a condensation exchanger (106/110) before the element (107) finally condenses all the water vapor that is under ambient pressure.

The other part of the condensation heat of the heat exchanger element (114) can be used to preheat the fuel and the combustion support material separately using the heat exchanger coil (131). This application of preheating the combined cycle fuel and combustion support material using the heat obtained in the coil (131) does not exclude any other type of additional use for which this heat can be applied, even if these applications are outside the energy cycle. When the cycle contains a heat exchanger element (131) for preheating the fuel and the combustion support substance of the combined cycle, it can, without any distinction, be located inside the element (114) or at the end of the channel (103) or (105), before the entry of vapors and gases into element (106).

According to specific additional embodiments, the method includes increasing the vapor pressure provided by the element (112) and the vapor pressure of the reboiler (113) and the condensate exchanger exiting the element (114), using additional mechanical compressors (115) and (117) connected in series and configured to provide sufficient pressure to send this steam to the main heat source (101).

One part of the condensate generated in the element (114) is used for cooling between the compression stages of the steam circulating through the cooling coil (118), while the rest of the condensate is returned directly to the reboiler (113).

According to specific additional embodiments, the method includes a bypass that connects the component Brayton cycle to the component main Rankine cycle, through which water is exchanged, this bypass is located between the discharge line of the regeneration condensate pump (111) and the inlet of the feed pump (119).

According to specific additional embodiments, the method also includes the use of the partial condensation heat of the steam coming from the reboiler (113) for other applications, in particular suitable for its use in an independent application, external to the installation in which the coil (131) is used.

According to specific additional embodiments, the method includes increasing the pressure of the steam provided by the reboiler (113) using additional mechanical compressors (115) and (117) connected in cascade, with cooling in between and configured to provide sufficient pressure to send this steam to the main source (101) of heat.

According to specific additional embodiments, it includes:

- in the case when the combined energy cycle is implemented as a closed one or burns only hydrogen, the steam is sent directly from the recovery channel of the RKK (103) to the turbine TND (127) of the secondary Rankine cycle, which operates under vacuum conditions provided by the condenser (128), from where the condensate returned as feed water to the constituent main Rankine cycle. With this method, the same heat transfer medium is used in the secondary Rankine cycle as in the rest of the power cycle.

According to the method of the present invention, exhaust gases from the recovery channel of the RKK (103) can be compressed using a fan (104), which sends them to the element (105) of the condensation exchanger, in which steam is generated in the evaporator (125) of an independent secondary Rankine cycle.

According to the method of the present invention:

- the heat pump UAX (200) is a refrigeration machine that operates through a combination of compression and absorption operations, using NH ₃ as the heat transfer medium and water as the solvent,

- the main generator (201) of the heat pump UAX (200) acts as a low temperature source, absorbing heat only from the element (107),

- the only low temperature heat pump source UAX (200) operates at temperatures between 80°C and 120°C,

- the ammonia absorber (210) of the UAX heat pump (200) acts as a high temperature source, transferring heat only to the reboiler (113),

- in the heat pump UAX (200) NH ₃ vapor is compressed, in successive stages with intermediate cooling,

- the compressed ammonia vapor condenser (207) of the heat pump UAX (200) releases all the heat released by the secondary generator (202), and

- the ammonia evaporator (209) of the heat pump UAX (200) generates supercritical NH ₃ using heat,

- supplied to it by the cooling coils between the compression stages (204 and 206), and

- part of the latent heat contained in the concentrated solution, which comes hot from the absorber (210).

The main part of the present invention is a hybrid compression-absorption type heat pump, "UAX" (Heat Exchange Absorber Unit), which can effectively and economically meet these requirements to realize the regeneration of the Brayton component of the combined cycle of this invention.

The UAX (200) absorber unit for heat exchange is a thermodynamic system with mixed functionality, compression and absorption of water and ammonia, which operates cyclically and continuously, which is used as a heat pump to transfer heat energy from the main generator (201), which desorbs ammonia and acts as a low temperature source, to an ammonia absorber (210) which operates at a higher temperature and acts as a high temperature source using a certain amount of mechanical energy provided from outside by the compressor unit (203).

The UAX absorption heat pump does not perform the combined energy cycle exchange, but still receives the mechanical work of compression from it, such as the heat absorbed by its low temperature source, to then return all this energy to the cycle through its high temperature source.

The combined cycle transfers mechanical energy from the transfer shaft (130) to the compressor system UAX and heat energy from the element (107) to the low temperature source UAX, while the latter returns all its energy to the combined cycle by transferring heat from the high temperature source to the reboiler (113), which regenerates water vapor at a higher temperature than that at which it was previously condensed.

From a functional point of view, the heat pump UAX (200) implements a thermodynamic cycle that works in "thermodynamic symbiosis" with the combined energy cycle with which it is energetically connected, in such a way that the operation of the installation according to the present invention is determined by the establishment of this functional relationship between the energy cycle and UAX. This represents a major difference with respect to prior art combined cycles.

KEY COMPONENTS OF A COMBINED ENERGY CYCLE

In order for a plant to operate according to the combined cycle of the present invention, as such, a number of basic pieces of equipment are necessarily required, without regard to its efficiency and ignoring any other types of factors that are decisive for the economic viability of this type of plant.

The "essential" components required for the operation of the plant according to the combined cycle of this invention are the following:

101: Primary heat source. This is the obligatory source through which heat enters the constituent Brayton cycle. The combined energy cycle receives energy from outside and necessarily through the main source of heat.

Three streams are available to the main heat source (101) (in addition to fuel and combustion support in cases of semi-closed cycles). On the one hand, the steam from the HPT turbine (122) of the main Rankine cycle component, and, secondly, the compressed steam from the Brayton component cycle. The third input stream, part of the condensate promoted by the pump (129), may be circulated through the heat exchanger element (118) before reaching the heat source (101) in case the power cycle has a vapor cooling system between compression stages.

Therefore, the main heat source (101) is one of the points where flows belonging to the component Brayton cycle and the component main Rankine cycle converge, which means that implicitly this is the point of exchange of matter between the two component cycles.

When the combined cycle is operated as a closed cycle, the main heat source (101) is always a high temperature heat exchanger that receives thermal energy from outside. In this case, the only substance that reaches the main heat source (101) is water, which, after increasing its enthalpy here, leaves in the form of superheated steam, which is sent to the high-temperature turbine HTT (102).

When the main heat source (101) is a pressurized oxy-combustion internal combustion chamber, the combined cycle is semi-closed. In this case, the water vapor sent to the high temperature turbine (102) circulates accompanied by the combustion gases themselves (mainly composed of carbon dioxide and more water vapor).

102: High temperature turbine. VTT. This is a gas turbine, the main component of the Brayton cycle, whose function is to generate mechanical work using the hot gas phase sent to it by the main heat source (101). It is called HTT (an acronym for High Temperature Turbine) for short, because it is the turbine that operates at the highest temperature in the entire plant.

The gas phase driving the turbine VTT (102) consists of steam accompanied by combustion gases in the case where the main heat source (101) is the combustion chamber. This gas phase, after expansion, exits the VTT turbine (102) at high temperature and is sent to the recovery channel of the RKK (103) to use the enthalpy contained in it.

103: Recovery channel. RKK. This is the gas side of the heat exchanger which recovers heat from the exhaust gases from the turbine (102). This heat contained in the turbine gases is used in the RSC (103) to generate the main high pressure steam for the component Rankine cycle using a set of evaporator tubes and superheaters (120). Part of the heat contained in the exhaust gases from the WTT turbine (102) can be used for external applications outside the cycle itself, in so-called "cogeneration". Optionally, for this purpose, and depending on the design operating parameters of the combined cycle, some independent element (133) of the heat exchanger may be located in the interior of the RAC (103).

In addition, when there is an intermediate pressure reheater (134), superheater (136), superheater (126) and low pressure evaporator (125), they will always be inside this RSC (103). Optionally, the heat exchanger coil (131) can be installed inside the RAC (103) located at the end of this channel, in front of the gas outlet.

Finally, the gases always leave the RSC (103) at the saturation temperature of the water vapor corresponding to the "ambient pressure".

In configuration 2 (Fig. 2) and in the main configuration (Fig. 1) of the presented combined cycle, the design provides for partial condensation of the water vapor circulating in the end section of the RKK recuperation channel (103).

Configuration 3, or design version of the combined cycle according to FIG. 3 and configuration 5 according to FIG. 6 are characterized by the fact that condensation does not take place in the recovery channel RKK (103), but a special channel (105) is provided in which condensation occurs.

For its part, configuration 4, or the design version of the combined cycle according to FIG. 4 is characterized in that there is a steam recovery connection in the RSC (103), just before condensation takes place, by means of which the steam is sent directly to the LPH turbine (127).

128: Heat sink. In this description, a heat sink (128) is any equipment, device or system through which the energy cycle transfers unused heat to the external environment. In this invention, it is always the steam condenser, the only element through which unused thermal energy is transferred to the outside. However, this function is indispensable for the functioning of the constituent main Rankine cycle for the installation of the present invention as a whole. Any heat exchange element that condenses the water vapor contained in the exhaust gases from the RSC (103) can function as a heat sink (128); however, and for reasons of energy efficiency, the most economical solution is to provide some system that recovers this heat (which has the ability to produce water vapor condensation at ambient pressure on the outside of the heat exchanger), such as, for example, an evaporator belonging to another additional Rankine cycle, or a coil that extracts heat destined for any type of application of interest (perhaps, for example, a recovery system connected to an absorption machine to produce industrial refrigeration). When a combined cycle has a secondary Rankine cycle, its condenser (128) is always the equipment through which heat is transferred to the outside.

109: Condensate return pump to the constituent main Rankine cycle. This is a pump that moves the condensate produced by the heat sink (128) and makes it circulate through the condensate return heater (110) before distributing the water that feeds the different parts of the cycle.

110: Heating element for feed water. It contains a heat exchanger together with the element (106) in which it is located. This is a tubular coil or any other configuration of heat exchange element, whose task is to raise the temperature of the condensate, which is returned to the cycle by means of pumping (109), using the heat from the condensation of steam occurring on the shell side of the exchanger (106).

106: Casing side of the condensate exchanger of the feed water heater. It contains a heat exchanger together with a condensate return heating element (110). This is the element of the exchanger through which the remaining steam obtained from the lower part of the RSC (103) circulates accompanied by non-condensable gases in the case of an oxygen combustion cycle. In the element (106) there is a partial condensation of water vapor. With the help of the heat released in this condensation, the temperature of the return condensate is raised using the condensate return heater (110).

From the condensing heat exchange element (106) to the element (107), a stream of water vapor exits, accompanied by all non-condensable gases, if any, produced during combustion (when the cycle is closed, there are no combustion chambers, and when the fuel is hydrogen with pure oxygen , combustion does not produce any non-condensable gases).

In the lower part of the heat exchanger element (106), liquid water is obtained from the condensation, which is then advanced by the regeneration condensate pump (111) along with the condensate flow from the element (107).

107: Regeneration condenser or liquefier. The element (107) transfers all the heat from the steam condensation to the main generator (201) which acts as the "low temperature source" of the heat pump UAX (200).

The regeneration condenser (107) receives steam and non-condensable gases from the element (106). In turn, from (107), non-condensable gases are obtained on one side, and condensed water vapor on the other side. The regeneration condenser (107) operates at "ambient pressure", which corresponds to operation at the lowest temperature of the Brayton cycle component. The simplest option, although not necessary, is to make the regeneration condenser (107), just like the heat exchanger element (106) and the outlet from the RKK (103), work at pressures close to atmospheric, and in such a case, the condensation temperatures in these three components will be close to 100°C.

Although this entails a deterioration in overall performance, a possible option, more complex, but more relevant from the point of view of industrial interest in semi-closed cycle configurations, is to make the element (107) be a CO ₂ liquefaction plant, in which all the heat released in successive compression cycles is transferred to the generator (201) UAX (200). The purpose of this configuration is to extract CO2 from oxy-combustion of CO2 from the energy cycle for storage, transport and handling as liquefied rather than taking it in a gaseous state.

The condition for element (107) to be a CO ₂ liquefaction plant is that the heat generated in the various compression stages must be at a temperature sufficient to transfer from the cooling exchangers between the CO ₂ compression stages to the main generator ( 201) UAX.

In this case, it should be assumed that the mechanical operation of the compressors is provided by the transmission shaft (130) of the installation itself (for simplicity, this representation has been omitted from all attached figures).

This heat that the power cycle gives off to the UAX (200) is returned later at a higher temperature by the reboiler (113) which works with the heat provided to it by the ammonia absorber (210) which acts as the "high temperature source" of the UAX (200).

Regardless of whether the combined cycle works in a closed or semi-closed cycle, in the element (107) there is always a complete condensation of the water vapor coming here from the element (106). As a consequence of this operation, the water vapor is liquefied while the CO ₂ generated in combustion remains confined to the concentrated gas or liquid phase.

Among other things, this means that the CO ₂ that exits the cycle does so at much lower temperatures than other conventional combined cycles. This CO ₂ outlet temperature can be further reduced if, for example, some other additional heat exchanger is provided for the return flow of the combined cycle condensate.

This phase separation that occurs in element (107) means that all the CO ₂ generated in the combustion chambers and any other non-condensable gaseous wastes that may accompany it can be removed from the cycle without having to come into contact with the atmosphere. .

This provides the energy cycle of this invention with an important environmental advantage over traditional open combined cycles, since it does not involve any direct emissions of any environmentally polluting gases into the atmosphere.

For oxygen combustion processes, it is common to burn with about 2 or 3% excess oxygen above the stoichiometric value to ensure complete combustion. This unreacted volume of oxygen circulates from the combustion chambers, passing through the RAC (103) and the heat exchanger element (106), being dissolved in the heat transfer medium, until it finally reaches the element (107), where it is eliminated from the cycle as non-condensable gas along with CO ₂ . When this occurs, the excess oxygen used for combustion can be recovered in the carbonic anhydride treatment plant for reuse as a combustion aid for the cycle.

Finally, degassed water is obtained at the bottom of the element (107), which is returned to the various parts of the combined cycle, pushed forward by the pump (111) for the regeneration condensate. Therefore, the only section of the energy cycle that can contain CO ₂ is the section from the combustion chambers (101) and (122) to the element (107).

113: Brayton component cycle recovery reboiler. It is the regenerator element of the Brayton constituent cycle, by means of which the "heat pump" UAX returns to the combined cycle in the form of heat the amount of energy that was previously recovered from the cycle itself using element (107), as well as the amount of energy that the compressors (203) UAX is taken from the transfer shaft (130).

The reboiler (113) is a heat exchange element whereby heat is returned to the power cycle from the ammonia absorber (210) which acts as the "high temperature source" UAX (200). With this heat supplied to the UAX (200) via the absorber (210), the reboiler (113) regenerates water vapor at a temperature and pressure higher than that at which it was previously condensed in the element (107).

Therefore, the regeneration of the Brayton component cycle using the UAX (200) heat pump takes place by recirculating the condensation heat of the steam at the temperature of the "low temperature source" in order to then return it to the cycle using the "high temperature source" in order to recover water vapor at a temperature and pressure above those at which it was previously condensed.

111: Pump for regeneration condensate of the Brayton component cycle. The pump (111) draws in the condensate generated in the condensing heat exchange element (106) together with the degassed water obtained in the bottom of the element (107) and forces it into the element (112) at a temperature sufficient to eventually feed the reboiler (113).

In the discharge line of this pump (111) for the regeneration condensate, a bypass is provided with the inlet line of the feed pump (119), through which water is exchanged between the component Brayton and Rankine cycles to establish the balance of matter and energy, which is necessarily required to enable the organization of the combined cycle according to this invention and which depends on plant design variables and cycle operating conditions.

112: Element (112) selected from:

- a heater (112) for supplying water to the reboiler itself (113),

- and a recovery exchanger (112) which, in addition to preheating the feed water for the reboiler (113) itself, can heat the feed water for the pump (119) and generate steam that can be sent to the compressor (115) and/or turbine heater (137 ) after raising its temperature in the superheater (136).

Element (112) is a tubular coil or heat exchange element of any other configuration, located inside the condensing heat exchange element (114), from which it receives heat, raising the temperature of the water that feeds the regeneration reboiler (113).

What enters element (112) is condensed water from pumps (109) and (111). What leaves the heat exchanger element (112) is

- the flow of heated liquid water, which is sent to the reboiler (113), and if it performs only this function, it is called a preheater (112).

Additionally, two more streams can exit from element (112):

- The flow of heated liquid water, which is sent to the feed pump (119).

- Steam flow (at pressure above atmospheric pressure) which is sent to the first additional stage of the steam compressor (115) or/and superheater (136), so that it is then partially expanded inside the additional turbine (137) before entering the LPH turbine (127).

114: Body side of the element condensate exchanger (112). This is a condensing heat exchange element, inside which there is an element (112). The steam from the recovery reboiler (113) circulates through this element (114) where the water vapor is partially condensed, whereby the enthalpy is restored in the element (112) which, in addition to preheating the water feeding the reboiler (113) itself, can heat the feed water for the pump (119) and/or generate steam. As a result of the ongoing partial condensation, a liquid water stream is obtained from the lower part of the element (114). This condensed water is advanced using the condensate pump (129) and part of it is sent to the main heat source (101), having previously passed through the heat exchanger element (118), which cools the vapor between the mechanical compression steps (115) and (117). The other part of the condensate, promoted by the condensate pump (129), is recycled directly to the reboiler (113). In the event that the combined cycle does not have auxiliary steam compressors (115) and (117), part of the condensate promoted by the pump (129) can be sent directly to the main heat source (101).

Optionally, and in order to improve cycle performance, it is also possible to provide an additional coil (131) inside the element (114), which, among other applications, can be used to preheat fuel and combustion support from their supply conditions. This coil (131) can also, without distinction, be located immediately before the inlet of steam and gases into the element (106). This coil (131) can also be used to extract heat from the element (114) intended for other types of external applications outside of the plant itself.

129: Condensate exchanger bottom pump (114). This is a pump that moves the condensate received from the bottom of the element (114) at a pressure sufficient to send it to the main heat source (101). When the combined cycle has compressors (115) and (117), this water stream, promoted by the condensate pump (129), circulates through the coil (118) to cool the vapor between the two compression stages. After the pump (129) for condensate, this flow is divided into two. One part is sent to the main source (101) of heat, having previously passed through the element (118) of the heat exchanger, in the case when the combined cycle has a compressor (115), while the rest of the condensate, promoted by the pump (129), returns directly to the reboiler (113 ).

119. Feed pump for the constituent main Rankine cycle. This is a pump that pushes water through the steam generating elements of the main Rankine cycle. This pump provides the highest pressure value achieved in the entire installation.

The feed pump (119) is fed mainly by the return flow of condensate promoted by the pump (109). In addition, the combined cycle has a bypass between the pump discharge port (111) and the pump inlet port (119) through which heat transfer medium (water) can be exchanged between the Brayton component and the Rankin component main cycle. It is also possible to supply the feed pump (119) with a stream of water heated in the element (112). The direction of flow in this bypass is determined by the project and cycle work variables.

120: Economizers or economizer tube sets of the constituent main Rankine cycle. These are heat exchange elements located inside the RKK (103) that serve to preheat the feed water from the feed pump (119) to a temperature close to its boiling point temperature, at a pressure at which steam is generated in the constituent main Rankine cycle.

121: Evaporator and superheater tube sets of the main Rankine cycle component. The evaporators and superheaters are heat exchange elements located inside the RSC (103) that generate the pressurized steam of the constituent main Rankine cycle. The water, preheated in the economizers (120), enters the evaporator tubes and eventually exits superheated steam, which is sent to the HPT turbine (122) or to the auxiliary heat source (132) if the power cycle includes this element.

122: High-pressure turbine (HPT) component of the main Rankine cycle. The purpose of this steam turbine is to generate work according to the constituent main Rankine cycle. The HPT turbine (122) receives superheated steam from the tube sets of the last superheater (121) or auxiliary heat source (132) if available. It is characterized by being the turbine that operates at the highest pressure in the entire plant, so it is called HPT (an acronym for "high pressure turbine") for short. This turbine operates at back pressure, performing a partial expansion of the gaseous fluid such that the outlet steam is pressurized enough to reach the main heat source (101) into which the outlet steam is sent.

When, although it does not matter, the power cycle has a TSD turbine (135), it receives steam from the outlet or exhaust of the HPT turbine (122).

130: Transmission shaft of the installation. This is an element or array of elements to which all the machines in the plant that require or generate mechanical work (turbines, pumps and compressors) are attached. This transmission shaft represents the point from which the plant's useful mechanical energy is obtained (to which the turbines, compressors and pumps of the plant are connected).

With the exception of the pumps and fan (104), the accompanying figures show a common transmission shaft (130) in order to make it easier to understand how the total mechanical combined cycle is obtained, although it is also possible to perform any energy cycle according to this invention using separate transmission shafts connected to separate generators or motors.

MAIN COMPONENTS OF A HEAT PUMP (UAX)

UAX, as mentioned, is the main component of the installation of the present invention, which works with ammonia and water.

The components that make up the UAX heat pump are shown in fig. 5 graphic materials. The hardware that makes up UAX is as follows:

201: Main generator. This is an ammonia stripper that acts as a "low temperature source" of UAX and is responsible for capturing the heat released by the element (107) belonging to the combined energy cycle. The main generator is fed with an intermediate concentration of ammonia water solution from the secondary generator (202), and wet ammonia gas exits on one side for compression, and on the other side a dilute solution is drawn by the transfer pump (215).

202: Secondary generator. This is a partial ammonia stripper which operates using the heat supplied to it by the compressed ammonia vapor condenser (207). All the concentrated solution produced in the ammonia absorber (210) enters the secondary generator after pre-cooling. From the secondary generator, wet ammonia gas exits on one side, to be compressed together with ammonia obtained from the main generator (201), and on the other side, partially degassed water, obtained from the bottom, to be sent to feed the main generator (201). The secondary generator (202) operates at a slightly higher pressure than the main generator (201) to force the solution to flow from one to the other.

203: Ammonia compressors. This term is applied to an array of series-connected compressors whose function is to increase the pressure of wet ammonia gas from two generators (201) and (202). Compression of ammonia gas is performed in successive compression stages connected in series with gas intercooling in order to maximize the overall efficiency of the process. To achieve this, the compressor array receives mechanical work from the transmission shaft (130) of the combined cycle unit. The compressor array (203) pressurizes the ammonia gas so that at least the saturation temperature of the NH ₃ is above the temperature at which the secondary generator (202) performs desorption so that heat transfer to this latter equipment is possible.

This refrigerant gas compression step does not occur in traditional absorption machines, so it is a hallmark of UAX. Due to the use of an absorption/desorption cycle in addition to compressors, the UAX (200) is believed to be a hybrid absorption/compression system that acts as a heat pump overall.

The compressed ammonia vapor that exits the last stage is made to circulate through the final compressed ammonia cooling element (205) and immediately following another cooling coil (206), which means that the heat contained in this compressed vapor is reused in other UAX elements.

204: Cooling elements for gaseous ammonia between successive compression steps. They consist of all the heat exchange elements responsible for cooling the ammonia gas between each pair of stages that make up the compressor (203). All these heat exchange elements are located inside the supercritical ammonia evaporator (209) to which they give all the heat they emit, and for this reason, the operating temperature of each of these cooling elements (204) must exceed the operating temperature of the supercritical ammonia evaporator (209).

205: Terminal cooling element for compressed ammonia. Together with the final heating element (216) for diluted solution forms a heat exchanger. Vapor circulates through the terminal cooling element (205) for compressed ammonia, which leaves the final stage of the compressors (203), giving off heat to the final heating element (216) in order for the diluted solution to reach the ammonia absorber (210) with a temperature not lower than the one at which gas absorption occurs in this element (210). In light of this fact, it is this element (205) that has the highest temperature in the entire UAX (200).

206: Cooling coil for compressed ammonia. It lies inside the evaporator (209) of supercritical ammonia, downstream relative to the terminal cooling element (205) for compressed ammonia. In this coil (206), the compressed ammonia gas is cooled before reaching the condenser (207) for the compressed ammonia vapor. The heat released by the coil (206) is used internally to generate ammonia gas in the ammonia vaporizer (209) so that it operates at a temperature above the NH ₃ critical point.

207: Compressed ammonia vapor condenser. In this equipment, the saturated ammonia vapor, under pressure provided by the compressors (203), is converted into a liquid phase and transfers all the heat it releases by condensation to the secondary generator (202), so that the latter can perform desorption. The compressed ammonia vapor condenser (207) receives ammonia in the gaseous state from the exchanger element (206) at the lowest possible temperature, although in such a way that the secondary generator (202) can operate correctly. An expander (218) separates the coil (206) from the condenser (207).

The liquid ammonia obtained from the compressed ammonia vapor condenser (207) is advanced to the supercritical ammonia vaporizer (209) using the condensed ammonia pump (208).

208: Condensed ammonia pump. This is a pump that moves condensed ammonia, with an outlet pressure above its critical point, from the compressed ammonia vapor condenser (207) to the supercritical ammonia evaporator (209). The pump discharge line (208) achieves the highest pressure in the entire UAX (200).

209: Supercritical ammonia evaporator. It receives the ammonia condensate promoted by the condensed ammonia pump (208) and converts it to gas at a temperature and pressure above the ammonia critical point (113.5 bar / 133.5°C). To achieve this, the evaporator (209) reuses the residual heat obtained on the one hand from the cooling coil (206) for compressed ammonia and the cooling elements (204) which transfer the heat that has been generated due to the Joule-Thomson effect in compressors (203). On the other hand, it also reuses the latent heat transferred to it by the concentrated solution coil (211) (more concentrated than the solution that comes from the desorber), through which one part of the concentrated solution leaving the absorber (210) circulates. This implies that the supercritical ammonia evaporator (209) performs its function using recycled heat from the UAX system itself without the need for input from other external heat sources.

The gas that exits the supercritical ammonia vaporizer (209) is immediately transferred to the absorber (210).

210: Ammonia absorber. Its purpose is to dissolve gaseous ammonia in water under conditions of supercritical pressure and temperature. This is the element that acts as the UAX "high temperature source" and is responsible for transferring the heat it generates to the combined power cycle regenerator reboiler (113).

The absorber (210) is fed with gaseous ammonia from the supercritical ammonia vaporizer (209) using an expander (217), and in addition, it is also fed with a dilute ammonia water solution from the main generator (201) after advancing by transfer pump (215) and preheating by heat exchangers. elements (214) and (216) in series.

The absorber (210) leaves a concentrated ammonia solution, which is sent to the secondary (202) and main (201) generators, thus closing the absorption-desorption cycle. After exiting the absorber (210), the flow of the concentrated solution is divided into two streams. One part is forced to circulate through the heat exchange element (213) of the countercurrent exchanger, while the rest of the flow circulates through the concentrated solution coil (211) which provides the heat with which supercritical ammonia is generated in the evaporator (209). Finally, after exchanging their heat, the two solutions of the concentrated solution are combined again in front of the expansion element (212).

The dissolution of ammonia in water under supercritical conditions is an exothermic process. The heat released by the ammonia absorber (210) is transferred to the reboiler (113) for steam recovery in a combined power cycle. Thus, the absorber (210) implements the function of the "high temperature source" UAX (200).

211: Evaporator concentrated solution coil (209). It is located inside the supercritical ammonia evaporator (209) where it releases heat by lowering the temperature of the concentrated solution circulating through this coil (211) from the ammonia absorber (210).

213: Heat exchanger element between dilute and concentrated solutions. The side of the concentrated solution. This element (213) forms part of a counterflow heat exchanger with a heat exchange element (214) to which it transfers heat. Through this element (213) circulates a complementary part of the concentrated solution leaving the ammonia absorber (210), which does not circulate through the coil (211) of the concentrated solution. The task of this heat exchange element (213) is to reduce the temperature of the concentrated solution before it enters the secondary generator (202).

212: Concentrated solution extender. When the two concentrated solution streams that have been cooled in the heat exchange elements (211) and (213) respectively are combined, the expander (212), located immediately before this concentrated solution enters the secondary generator, ensures that an operating pressure is reached at which desorption takes place in the secondary generator (202).

214: Heat exchange element between dilute and concentrated solutions. Diluted solution side: This element (214) forms part of a counterflow heat exchanger with the element (213) from which it receives heat. The purpose of this countercurrent heat exchanger is to ensure that the concentrated solution enters the secondary generator (202) at the lowest possible temperature, while still being able to heat the dilute solution before it enters the ammonia absorber (210).

This heat exchange element (214) circulates the dilute solution from the main generator (201) propelled by the transfer pump (215) before it reaches the absorber (210) to be heated in countercurrent with a portion of the concentrated solution.

215: Transfer pump for thin solution. This is a pump that moves the dilute solution leaving the main generator (201) and sends it to the ammonia absorber (210), but with a preliminary passage through the heat exchange elements (214) and (216), the purpose of which is to increase its temperature.

216: Diluted Solution Terminal Heating Element. The heat exchange element (216) constitutes a counterflow heat exchanger with an end cooling element (205) for compressed ammonia. This element circulates the dilute solution from the heat exchange element (214) and uses the heat transferred from the steam that exits the final stage of the compressors (203) to ensure that the solution reaches the ammonia absorber (210) at the same operating temperature.

217: Ammonia gas expander towards absorber (210). The expander (217) serves to bring the supercritical ammonia pressure from the evaporator (209) into line with the operating pressure of the ammonia absorber (210).

218: Gaseous ammonia expander towards compressed ammonia condenser (207). The ammonia expander element (218) creates the pressure and temperature drop necessary to operate the compressed ammonia vapor condenser (207) so that heat exchange between the condenser (207) and the secondary generator (202) can be established.

The specific characteristics of a Heat Exchange Absorber (UAX) unit are determined by the operating requirements and variables of the combined cycle with which it operates.

In order to effectively "regenerate" the Brayton cycle component of this invention, the heat pump UAX (200) must satisfy the following conditions:

- energy exchange only with an energy cycle that is maintained. That is, all heat absorbed by the low temperature source must be taken from the energy cycle, and all heat released by the high temperature source must be transferred back to the energy cycle at another point. The exchange of energy with the external environment would represent a loss of efficiency;

- the low-temperature source UAX must capture, in order to recover, the heat of condensation of water vapor at ambient pressure (between 80°C and 120°C);

- it is required to achieve the largest possible thermal step (temperature difference) between the UAX sources, since the high temperature source must regenerate the condensed saturated water vapor in advance, but at the highest possible pressure, in order to improve the efficiency of the system;

- performance (COP) should be as high as possible: in other words, the amount of calories transferred from a low temperature source to a high temperature one should be very large compared to the mechanical work consumed by the compressor;

- all the energy (mechanical and thermal) that the UAX heat pump takes from outside must be supplied by the transmission shaft (130) of each combined cycle that is supported;

- all heat energy (other than direct losses of the UAX itself) that the UAX heat pump releases must exit via its “high temperature source” and be used for steam recovery in the power cycle via its reboiler (113).

Each absorption machine, and therefore also the UAX, operates according to a cyclic absorption-desorption process. Absorption is the process of dissolving a gas in a liquid solvent. The reverse reversible process in which gas is released from solution is known as desorption. In the specific case of UAX, ammonia is used as the solute and water as the solvent.

The absorption of ammonia in water is a reversible exothermic process, so heat is released in each absorber as the gas dissolves into the liquid phase. For its part, the reverse process of desorption of ammonia in water, which occurs in the generator, always turns out to be endothermic, which means that a heat supply is necessary for its operation.

The UAX is considered to be a hybrid compression/absorption heat pump because its operation shares common features with both systems. This means that the UAX necessarily consists of an absorber, desorber, evaporator, condenser and compressors, in addition to pumps, gas expansion elements and heat exchangers.

Traditional absorption machines are systems consisting of two centers through which the machine absorbs heat from the outside (generator and evaporator), and two more through which the machine releases heat into the external environment (absorber and condenser).

However, for the application of the "heat pump" in the regeneration of the combined cycle of this invention, it is absolutely necessary that it consists of only one "low temperature source" (from which it receives low temperature heat from the power cycle) and only one "high temperature source" (through which heat is returned to the cycle, but at a higher temperature). It is this fundamental feature of the UAX that distinguishes it from other absorption machines.

Although the UAX(200) is made up of the same fundamental elements as any other absorption machine, it is characterized by absorbing external heat from only one source and releasing it from only one other (assuming that direct losses can be neglected). This is achieved by recycling the heat released by some of its elements and reusing the internal heat to provide the heat needed by other elements.

Due to the physicochemical similarity exhibited by the components of a solution, the process of dissolving a gas in a liquid is always more exothermic than simply condensing it. A direct consequence of this is that in the absorption machine, the centers that work by absorption-desorption - the absorber (210) and the main generator (201) - release and absorb, respectively, more heat than is released in the condenser (207) of the compressed ammonia vapor and absorbed in the evaporator (209) of supercritical ammonia.

In order to successfully transfer maximum specific heat from its low temperature source to its high temperature source, the UAX internally reuses certain heat flows to prevent its compressed ammonia vapor condenser (207) and its supercritical ammonia vaporizer (209) from exchanging energy with the outside, so to keep the absorber (210) and the main generator (201) as the only high and low temperature sources, respectively.

From a thermodynamic point of view, and unlike compression chillers, conventional absorption machines cannot strictly be considered heat pumps because they do not transfer heat from a colder source to a warmer one. Typically, the machine absorbs heat through both the coldest element (evaporator) and the hottest element (generator) at the same time.

One feature of the UAX (200) that makes it different from other traditional absorption machines is that it actually acts like a heat pump, transferring heat energy from a cold to a warmer location. This is achieved by having the UAX heat pump operate at its operating pressures in reverse of how chillers normally operate.

In any refrigeration machine, whether based on compression or absorption, there is one part of the circuit that operates at high pressure and another that operates at low pressure (the condenser operates at a higher pressure than the evaporator).

In the case of a compression heat engine, the pressure difference between the evaporator and condenser is forced by the compressor. Zones of different pressure are demarcated between the compressor and the expander.

In absorption machines, the generator and condenser operate at higher pressures than the evaporator and absorber. It is the operation of the absorber-desorber system itself that stimulates the pressure difference that exists between one and the other components.

One special feature of the UAX is that it operates at the inverse operating pressures of conventional refrigeration machines: in other words, its supercritical ammonia absorber (210) and evaporator (209) operate at a higher pressure than its compressed vapor condenser (207). ammonia and its main (201) and secondary (202) generators. To achieve this, the transfer pump (215) circulates the dilute solution from the generator (201) to the ammonia absorber (210), which operates at a higher pressure.

The UAX(200) needs mechanical aids to handle back pressures. This distinguishes the UAX from any other traditional absorption machine, since the pressure difference in the circuit is not stimulated, but is forcibly created using compressors and pumps for this.

In order to achieve reverse pressure operation of the UAX, the operating temperatures of the absorber (210) and the main generator (201) must be precisely determined, since two counter-effects are simultaneously created that affect the solubility of ammonia in water. On the one hand, the liquid phase should be able to dissolve more gas at higher pressures, but on the other hand, the gas will become less soluble at higher temperatures.

Obviously, in order for the system to be able to work as a heat pump, it is required that the solubility of ammonia in water is always higher in the absorber (210) than in the main (201) and secondary (202) generators, since in any absorber there is always an increase concentration when the gas is dissolved, whereas in any generator a dilute solution is always obtained, since this is where gas desorption occurs.

To achieve maximum efficiency, it is necessary to find the ideal compromise between operating temperatures and pressures in each case, since, on the one hand, desorption is stimulated in the main (201) and secondary (202) generators by lowering the pressure, while the efficiency of the ammonia absorber (210) increases with its working pressure. However, given that the purpose of the UAX is to act as a heat pump, the intention is that the thermal step between the high and low temperature sources is as large as possible. However, as the temperature in the absorber (210) rises, the ammonia tends to become less soluble, while as the temperature drops in the main (201) and secondary (202) generators, the solubility tends to increase, degrading the desorption performance.

A thermodynamic system that can transfer heat from one low temperature point to a warmer point using a compressor is known as a "heat pump" and it is this function that the "Heat Exchange Absorber Unit" of this invention implements.

In light of the above, it should be pointed out that in order to make the "Heat Exchange Absorber Unit" (UAX) work as a heat pump supporting the energy cycle of the present invention, it is necessary to make a number of special modifications, which are special features of the UAX (200). These specific modifications that distinguish UAX from other absorption cycles are:

1. In order to get the ammonia absorber (210) to generate heat, but at a higher temperature than that at which the main generator (201) operates, the operating pressures must be reversed: in other words, the absorber (210) must operate at a higher pressure than the component with which ammonia is desorbed, the main generator (201). To achieve this, a transfer pump (215) is needed to push the dilute solution into the ammonia absorber (210) and expansion element (212) for the concentrated solution before it enters the secondary generator (202).

2. In order for the UAX not to lose heat to the external environment, it is necessary to recycle the heat released by the condenser (207) of the compressed ammonia vapor, transferring it to the desorber of the secondary generator (202), so that the operating temperature of the former should be slightly higher than the temperature of the latter. It is necessary to pressurize the ammonia vapor using compressors (203) so that it condenses at a higher temperature than when it evaporates in solution in the generator.

3. Keeping in mind that the heat released by the compressed ammonia vapor condenser (207) is recycled in the UAX itself, the ammonia absorber (210) is the only point through which heat is released to the outside (if direct heat loss from heat transfer, convection and radiation is assumed to be negligible).

4. To improve efficiency, the compression of ammonia used as a gaseous refrigerant is carried out in several stages with intermediate cooling. This implies that there is some heat between the compression steps that needs to be removed. Furthermore, it is of interest that the compressed ammonia vapor reaches the compressed ammonia vapor condenser (207) at the lowest possible temperature, always provided that it can still transfer heat to the secondary generator (202).

By properly selecting the operating temperatures of the system, it is possible to provide the heat needed by the evaporator (209) by transferring to it the excess heat contained in the vapor stream after the compressors (203) and the concentrated solution leaving the absorber (210) to convert the ammonia to a supercritical state. . When the sum of these volumes of excess heat satisfies the need of the ammonia evaporator (209), then the need to bring heat from the outside to obtain ammonia in conditions above its “critical point” is lost, at the same time, the need to remove cooling heat to the external environment also disappears.

5. By supplying the heat needed by the supercritical ammonia evaporator (209) using heat recycled from the system itself, the main generator (201) becomes the only source through which the UAX receives heat from the outside.

By implementing all these modifications properly, it is possible to design an absorption machine which, using an array of compressors connected in cascade (203), does not allow its condenser (207) vapor of compressed ammonia and its evaporator (209) supercritical ammonia to exchange heat with the external environment, leaving the main generator (201) as the only low temperature source through which the system absorbs heat from the external environment, while the absorber (210) operates at a higher temperature, acting as the only high temperature source through which heat is released to the external environment.

HEAT PUMP OPERATION (UAX)

1. In order for the UAX (200), like any other absorption system, to operate continuously in a closed cycle, it is necessary to install a solution interchange circuit between a component that “absorbs” gas to obtain a concentrated solution, and another that “desorbs” to obtain a dilute solution. In other words, the dilute solution leaves the main generator (201) and circulates to the ammonia absorber (210), while the concentrated solution leaves the absorber (210) and circulates to the main generator (201) in the opposite direction to be recirculated again.

As described above, countercurrent circulation is established for the two solutions between one piece of equipment and the other (absorber (210) and generator (201), but in the opposite direction.

Given that the generators (strippers) and absorbers of the absorption machine always operate at different pressures, the solution flows from the higher pressure machine to the lower pressure machine without the need for mechanical assistance. However, the other solution circulating in countercurrent from the lower pressure equipment to the higher pressure equipment needs to be driven by a pump.

In the UAX (200), unlike traditional absorption machines, the absorber (210) operates at a higher pressure than the main generator (201) and therefore the transfer pump (215) moves the dilute solution from the main generator (201) into the absorber ( 210).

2. The UAX (200) consists of two desorbers or generators, one of which is called the secondary generator (202) and the other is called the main generator (201). The two generators operate in cascade, which means that the partially desorbed solution leaving the secondary generator (202) is the feed to the main generator (201).

The desorption of ammonia requires the addition of heat as it is an endothermic process, so all generators require heat to operate. In UAX, each generator receives heat from a different source: The secondary generator (202) is supplied with heat by a compressed ammonia vapor condenser (207), while the main generator (201) receives heat from a combined cycle. Therefore, the operating temperature of the main generator (201) is always determined by the condensing temperature of the fluid in the constituent Brayton cycle. This condensation takes place in the element (107).

The operating pressure of generators (201) and (202) UAX (200) depends on the degree of desorption (dilute solution concentration) for which the UAX is designed, although the secondary generator (202) always operates at a pressure significantly higher than the main generator (201), so that a solution of intermediate strength flows from one of them to the other without the need for mechanical means.

The main generator (201) is the equipment that operates at the lowest pressure in the UAX (200) and therefore the dilute solution produced from this component is required to circulate propelled by the transfer pump (215) at a pressure sufficient to feed the ammonia absorber (210).

3. Ammonia steam obtained from two generators, main (201) and secondary (202), as well as obtained in any traditional desorber, always contains a certain amount of moisture. In this patent, the term "ammonia steam" in UAX (200) always refers to "wet" ammonia steam, unless otherwise indicated. In this description, this wet ammonia is not specifically considered in any way, since this degree of moisture is very low under the pressure and temperature conditions required for UAX, and this does not change the basic functioning of the cycle.

This ammonia stripped in generators (201 and 202) is sent to an array of compressors (203). Here, the compression process is carried out in successive stages with intermediate cooling of the fluid to be compressed, with two goals: to increase the mechanical efficiency of compression on the one hand, and on the other, to have several heat reservoirs able to provide heat to the evaporator (209) of supercritical ammonia. That is, a set of cooling elements (204) transfers this heat to the ammonia vaporizer (209) between compression steps, thus preventing it from being lost outside of the cycle.

The compressor set (203) receives its mechanical work from the combined cycle itself via the transmission shaft (130), so that this work is considered to be the own consumption of the combined energy cycle. Given that the lower the intrinsic mechanical energy consumption, the greater the overall efficiency of the combined cycle, it is of interest that the compression process be as efficient as possible.

The residual pressure of the vapor leaving the final stage of the compressors (203) is determined by the operating pressure of the compressed ammonia vapor condenser (207), and this in turn is a direct function of the temperature at which desorption occurs in the secondary generator (202) with which it exchanges warmth.

4. The operating requirement of the UAX is that the ammonia vapor must exit the last stage of the compressors (203) at a temperature higher than that of the absorber (210), so that the compressed ammonia final cooling element (205) can heat the dilute solution to ensure that the liquid phase enters the absorber (210) at a temperature not less than that at which the ammonia vapor dissolves in this equipment.

5. It is also a prerequisite for the functioning of the UAX (200) that the compressed ammonia vapor leaving the different cooling elements (204) for gaseous ammonia, as well as the final cooling element (205) for compressed ammonia, be at a higher temperature than the temperature of the supercritical ammonia evaporator (209), so that this heat can be transferred using the compressed ammonia cooling coil (206), which generates supercritical ammonia.

6. After the heat has been removed, the ammonia vapor is withdrawn from the compressed ammonia coil (206) at the lowest possible temperature close to the saturation temperature in the compressed ammonia vapor condenser (207) and is then partially expanded in the expander (218) to reach operating pressure. capacitor (207).

7. In the condenser (207), the compressed ammonia vapor is converted to liquid, releasing heat, which is completely transferred to the secondary generator (202), so that the latter can partially desorb the concentrated solution.

In order to transfer heat from the compressed ammonia vapor condenser (207) to the secondary generator (202), the saturation temperature of the ammonia vapor that is present in the compressed ammonia vapor condenser (207) must be slightly higher than the desorption temperature that is present in the secondary generator (202) . Given that the saturation temperature corresponds to a certain specific pressure, it is the latter that determines the residual pressure of the compressors (203).

8. The liquid phase ammonia collected at the bottom of the compressed ammonia vapor condenser (207) is sent to the supercritical ammonia vaporizer (209) propelled by the condensed ammonia pump (208) at a pressure above its "critical point" pressure.

9. When supercritical ammonia enters the evaporator (209), liquid ammonia first heats up and then passes into a gaseous state at a pressure and temperature above the pressure and temperature of the "critical point" of ammonia (113.5 bar / 133.5 ° C).

The heat that the supercritical ammonia evaporator (209) needs to perform its function is obtained by recovering the excess heat released by the elements (204), (206) and (211) of the UAX itself, at a temperature sufficient for this.

The heat exchange elements that supply the heat required by the supercritical ammonia evaporator (209) are as follows:

- An array of cooling elements (204) between different stages of compression.

- Cooling coil (206) which cools the compressed ammonia vapor before it enters the compressed ammonia vapor condenser (207).

- An exchange element (211) through which part of the hot concentrated solution circulates, which exits the ammonia absorber (210).

In order for UAX to operate efficiently, being energy dependent only on the combined cycle, it is necessary at all times to maintain equality between the amount of heat that is required by the evaporator (209) of supercritical ammonia, and that which is added by the array of elements (204), (206) and (211) exchange, respectively.

In UAX, this heat balance is achieved and controlled by making the evaporator (209) operate at a pressure above the critical point pressure of ammonia. This is the fundamental feature that distinguishes the UAX from any other traditional absorption machine.

By operating at pressures slightly above the critical point pressure of NH ₃ in the evaporator (209), it is possible to change the amount of heat absorbed here. When the pressure and temperature of ammonia exceed its critical point, a "thermal anomaly" occurs in which small pressure variations in the supercritical fluid require large enthalpy changes for each small temperature variation (in the pressure-enthalpy diagram for ammonia, the isotherm lines become nearly horizontal immediately after passing through critical point).

A direct consequence of the above is that the energy balance in the evaporator (209) supercritical ammonia is achieved by making minimal modifications to the pressure at which it operates. This, in turn, is achieved by the combined action of the condensed ammonia pump (208) and the expander (217), giving the system as a whole an extremely flexible operation.

10. When ammonia leaves the evaporator (209) under supercritical conditions, it flows into the absorber (210) due to its own pressure.

There is a valve (217) in the gas inlet line to the absorber (210) which is responsible for adjusting the operating pressure of both the ammonia absorber (210) and the supercritical ammonia evaporator (209).

By adjusting the operating pressure of the absorber (210), the concentration of ammonia in the solution, the operating temperature and the heat released in this equipment are controlled.

11. In addition to the ammonia in the gaseous state, the ammonia absorber (210) also receives all the dilute solution from the main generator (201), after it has been advanced by the transfer pump (215) and heated in the heat exchange elements (214) and (216). When the two streams are mixed, a gaseous ammonia solution is obtained, with which the aqueous solution increases its concentration of ammonia, giving rise to the so-called "concentrated solution". Obviously, for this to happen as described, the ammonia must always be more soluble in the absorber (210) than in the generators (201 and 202). This is achieved by making proper selection of the operating pressures and temperatures of the absorber (210) and generators (201 and 202).

In order to be able to increase the solubility of ammonia in water when design conditions require it, chemicals can be added to the solution that can form complex radicals with the ammonia ion (such as, for example, silver chloride).

The concentrated ammonia solution obtained in the absorber (210), after being cooled, is sent to the generators (202 and 201), thus closing the working cycle.

As a result of the ammonia gas dissolution process, the amount of concentrated solution leaving the absorber (210) always exceeds the amount of dilute solution leaving the main generator (201).

This is important for exchanger design as the concentrated solution leaves the absorber (210) at a temperature sufficient to recycle its enthalpy in the counterflow exchanger (213/214) on one side and the heater (211) located inside the evaporator (209) on the other. .

12. To perform this dual function of heat exchange, the hot stream of concentrated solution leaving the ammonia absorber (210) is split into two. On the one hand, some solution circulates through the heat exchange element (213) to preheat the dilute solution in countercurrent, which circulates through the heat exchange element (214), while the rest of the solution circulates through the concentrated solution coil (211), giving off heat to the evaporator ( 209) to produce supercritical ammonia.

13. After releasing their enthalpy and cooling, the two streams of concentrated solution are again combined into one before entering the secondary generator (202).

The expansion element (212), located upstream of the secondary generator (202), operates at a pressure at which this equipment partially desorbs the ammonia contained in the concentrated solution.

14. The partial desorption that occurs in the secondary generator (202) releases some moist ammonia gas, which is sent directly to the compressor (203).

The heat required by the secondary generator (202) to desorb the ammonia gas is obtained by heat exchange with the compressed ammonia vapor condenser (207), without the need for any additional heat source.

The intermediate concentration solution obtained from the bottom of the secondary generator (202) flows into the main generator (201), fed by it, under its own pressure, without the need for mechanical means.

15. In the main generator (201) the second desorption phase in the cascade takes place. As a result of this process, additional ammonia vapor is released, which is sent directly to the compressors (203) along with the vapor produced in the secondary generator (202).

From the bottom of the main generator (201) a dilute ammonia solution is obtained (more dilute than the output from the secondary generator (202)), which is re-sent to the absorber (210) by means of a transfer pump (215) for the diluted solution, thereby closing the absorption cycle - desorption.

The heat that the main generator (201) needs to be removed from the final stage of desorption is supplied from outside the UAX, by heat exchange with the element (107) of the combined energy cycle.

The main generator (201) is the equipment that operates at the lowest UAX temperature, being the only point in the cycle through which the UAX receives heat from outside in such a way as to act as the "low temperature source" of this heat pump.

In order for the UAX to operate efficiently, the operating pressure and temperature of the main generator (201) must be carefully set to meet a number of mandatory requirements. On the one hand, it is necessary that the solubility of the ammonia gas under the conditions of the secondary generator (202) be lower than at any time in the ammonia absorber (210). This is achieved by increasing the desorption temperature: however, on the other hand, the purpose of the UAX (200) is to operate as a heat pump, and it is essentially of interest that the main generator (201) act as a low temperature source, do so at the lowest possible temperature, which actually means that the solubility tends to increase, the opposite of what is required.

16. The dilute solution produced in the main generator (201) is sent to the absorber (210) so that the UAX operates in a closed loop. This requires that the transfer pump (215) that moves the dilute solution does so at pressures above the critical point pressure of ammonia at which the absorber (210) operates.

17. Given that the ammonia absorber (210) acts as a high temperature source, it is of interest to improve efficiency that it can transfer as much heat as possible to the combined cycle reboiler (113). For this, it is advantageous that the dilute solution appears on the absorber (210) at the highest possible temperature.

In contrast, the efficiency of the UAX is increased when the main generator (201), which acts as a low temperature source receiving heat from outside, receives a dilute solution at low temperatures.

To increase the overall efficiency of UAX (200) and simultaneously meet both requirements, a counterflow heat exchanger is placed between the dilute and concentrated solutions, consisting of heat exchange elements (214) and (213), respectively.

18. The diluted solution, after being preheated in the above exchanger, passes through another terminal additional heating element (216), which raises the temperature of this solution even more before it enters the ammonia absorber (210).

As previously mentioned, the dilute solution end heating element (216) receives heat from the compressed ammonia end cooling element (205) (which has the highest temperature in the entire UAX (200)), through which the ammonia vapor exiting the end stage of the compressors circulates. (203).

19. This UAX (200) cycle is closed in the absorber (210) where the dilute solution is mixed with ammonia gas to dissolve the latter, resulting in a concentrated ammonia solution. This is an exothermic process, which means that heat is released in it. It is this heat that is transferred to the external reboiler (113), thus the absorber (210) becomes the "high temperature source" of UAX.

Ideally, or in other words, ignoring the inevitable direct heat loss due to conduction, convection and radiation, the absorber (210) is the only point at which the UAX releases heat to the outside.

The process of dissolution of gaseous ammonia occurring in the absorber (210) is realized at unusually high temperature and pressure (above the temperature and pressure of the critical point of NH ₃ ), leading to the fact that the solubility of ammonia in the absorber (210) is always greater than in the generators (201 and 202).

This is achieved, contrary to what is intended for the generator (201), by lowering the temperature of the solution: however, and on the other hand, given that the function of the UAX is to work as a heat pump, it is understood that the ammonia absorber (210), acting as a high temperature source, should do so at the highest temperature possible, which definitely does not increase solubility.

20. The overall result of running the UAX cycle (200) taken together is that the system operates like a heat pump in such a way that there is a single high temperature source consisting of the ammonia absorber (210) and a single low temperature source including the main generator ( 201).

Ignoring direct losses and in accordance with the principle of conservation of energy and the second law of thermodynamics, UAX releases into the power cycle through the absorber (210) an amount of heat equivalent to the sum of the heat that the main generator (201) captures from the power cycle and the mechanical energy that the compressors (203) and cycle pumps receive from the transfer shaft (130). This implies that the heat pump UAX (200) always delivers more heat through the regenerator reboiler (113) to the combined cycle of the present invention than it takes heat from the combined cycle of the present invention through the element (107), and this heat difference is less than better UAX performance (200) (high efficiency equals high performance). This has direct implications for the power cycle as it means that the reboiler (113) will need to be supplied with additional water in addition to all the condensate produced in the element (107).

HEAT PUMP (UAX) INTEGRATION IN COMBINED ENERGY CYCLE

The operation of the combined cycle according to this invention requires that the heat exchange absorber unit UAX (200) be integrated within one plant, realizing the function of "regenerating" the component Brayton cycle, recirculating the heat released at the coldest point of the cycle to prevent it from being lost, as it happens in other traditional combined cycles.

The regeneration of the component Brayton cycle by means of a heat pump in this invention is carried out by:

- using a condensing heat transfer medium (steam) instead of gas, as occurs in conventional Brayton cycles,

- taking a certain amount of mechanical work from the energy cycle to ensure the functioning of the heat pump UAX (200),

- capturing the heat of condensation released from the energy cycle by means of the "low temperature source" UAX (200),

- recovery of heat and work from the energy cycle by means of a "high temperature source" UAX (200) generating water vapor at a higher pressure and temperature than that which occurred previously during the condensation.

To implement this class of "regeneration" of the constituent Brayton cycle, the installation contains:

- a heat exchange system formed by the element (107), which transfers the heat of condensation of water vapor at ambient pressure to the low-temperature source of the heat pump UAX (200),

- a regenerator reboiler (113) which operates at a higher temperature than the element (107) generating water vapor at a higher pressure with the help of heat returned to it by the UAX heat pump (200) through its high temperature source,

- pump (111) for regeneration condensate, which promotes the condensate from the element (107) to the regenerator reboiler (113). The condensed water is sent from the element (107) to the recovery reboiler (113).

The regeneration method for the component Brayton cycle using the heat pump of this invention provides two separate advantages over traditional Brayton regenerative cycles:

- It allows the heat released by the constituent Brayton cycle to be recirculated exactly at the point in the cycle where the temperature is lowest.

- It regenerates the compressed fluid because water vapor is condensed at one pressure and then steam is regenerated but at a higher pressure. This minimizes the mechanical work of compression required to transfer the steam to the main heat source (101) of the Brayton component cycle.

In order for this type of regeneration using a heat pump (200) to be possible, it is also required that the transfer shaft (130) of the plant supply the mechanical work of compression necessary for its operation, which is considered additional own consumption.

Disregarding direct losses and following the principle of conservation of energy, the UAX(200), like any heat pump, releases through its high temperature source an amount of thermal energy equal to that absorbed by its low temperature source plus the work consumed by the compressor. In other words, a high temperature source always releases more heat than a low temperature source absorbs. Given that UAX does not exchange energy with the environment, this mechanical work of compression, consumed from the energy cycle, is later returned in the form of additional heat by the reboiler (113). For this reason, in addition to all the condensate generated in the element (107), it is necessary to provide the reboiler (113) with an additional amount of water for evaporation.

In any case, logically, it turns out that the higher the output (COP) of a UAX (200) heat pump, the higher the overall efficiency of the combined energy cycle will be.

One particular feature of the use of the "brayton component" variant that uses a condensable fluid is that it allows the heat transfer medium to be exchanged with the "component main rankin cycle" of the combined cycle of the present invention. In the combined cycle, which is the subject of this invention, the amount of additional water that needs to be evaporated by the reboiler (113), relative to the element (107), is obtained from the flows from the component main Rankine cycle or connecting lines between component cycles (Brighton and Rankine).

This ability to interconnect the component Brayton and Rankin cycles of the combined cycle of this invention generates other types of advantages, such as the ability to simplify installation using elements common to both cycles.

The purpose of incorporating a heat pump into the Brayton component cycle is to "regenerate" it, recirculating the heat released at the coldest point in the cycle and thus preventing it from being wasted. This type of regeneration is only possible when the Brayton cycle is "closed" or "semi-closed": in other words, only when the heat transfer medium is not vented to the atmosphere, but is returned to the cycle.

- "Closed-loop" operation is carried out when the plant is operated without an external supply of material, in which case the input energy is supplied by heat exchange with an external source at a temperature sufficient for this purpose (for example, it can be solar or nuclear).

- Operation in a "semi-closed cycle" is carried out when the input of energy into the installation occurs through the process of "internal combustion in oxygen" carried out in the combustion chamber.

In the case where the combined cycle is semi-closed, it has at least one combustion chamber as a source of energy supply to the power cycle. In any combined cycle combustion chamber, only industrial grade pure oxygen is used as a combustion aid, diluted in pressurized water vapor in a process known as "oxygen combustion", in which the gases of this chemical reaction form part of the heat transfer medium in the combustion chamber. Thus, in a semi-closed combined cycle, in addition to using "oxygen combustion", "internal combustion" is also used.

Any element or substance other than O ₂ present in the combustion aid (such as nitrogen, sulfur, etc.) is undesirable because it fouls the heat transfer medium and poses a risk of problems in the operation of the combined cycle. This prevents the use of air as a combustion support agent in this combined cycle.

The semi-closed combined cycle can use any fuel that meets the following requirements:

- The fuels used must be liquid or gaseous, never solid.

- The fuel used in combined cycle combustion chambers may contain a single substance or be a mixture of several types of fuel.

- The chemical composition of substances used as fuels satisfies the general formula C _X H _Y O _Z , where the letters C, H and O refer to the elements carbon, hydrogen and oxygen, respectively, and the subscript characters "X, Y, Z" represent the stoichiometric the content of each of these elements according to the following prescriptions:

- The subscript "Z" for oxygen in the general formula can be zero or any other value. Accordingly, any hydrocarbon that satisfies all of the above requirements is suitable for use as a combined cycle fuel.

- Pure hydrogen can be used as a fuel in any case. However, for plants using H ₂ as the sole fuel, and for reasons of efficiency and ease of installation, this should be considered a special case, according to the combined cycle configuration 4 (FIG. 4).

- The case where the subscript "Y" for hydrogen can take on a null value.

- Any other chemical compound containing elements other than carbon, hydrogen and oxygen is undesirable.

- Fuels suitable for use must be real chemicals that can chemically react with oxygen in an exothermic combustion process.

- The combustion chemical reaction must be carried out without the simultaneous implementation of any other type of secondary chemical reaction.

In any "semi-closed" process of "internal combustion in oxygen" the continuous introduction of matter into the cycle occurs by nature (in the form of fuel and combustion support), so that in order to establish a balance of matter in the cycle, it is necessary that the amount of incoming substance be removed to another parts of the cycle in the form of combustion products. Once the combustion products are removed from the cycle (CO ₂ in liquid or gaseous state and liquid H ₂ O, respectively), their subsequent processing for any type of industrial application is very simple, without the greenhouse gas emissions that open cycles entail. In the cycle of this invention, the water exits in liquid form at ambient temperature, with little environmental impact, while, on the other hand, CO ₂ is obtained in a concentrated and isolated form without the need for any special procedure to capture it.

In fact, this particular feature of the combined cycle, according to which the combustion products are discharged "individually, concentrated and at low temperature", is one of the fundamental principles due to which the present energy cycle provides higher efficiency than other open combined cycles of the prior art.

One of the fundamental features of the energy cycle of this invention, which distinguishes it from traditional combined cycles, is the indispensable condition for the existence of an energy balance at any time, that is, the energy entering the energy cycle through the sources (101) and (132) of heat must be equal to the sum of the energies, leaving the energy cycle through the transfer shaft (130) as useful work of the cycle, and heat given off through the outlet (128).

Any variation that occurs between the constituent Brayton cycle, the constituent major Rankine cycle and UAX must be compensated to maintain this equality by transferring heat between them, and for this an important condition is the constant existence of a temperature differential between one fluid and another, allowing this. Otherwise, it will be necessary to remove energy from the cycle, losing mechanical energy or productivity.

One of the fundamental aspects of this invention is to establish a constant energy balance between the energy cycle and the UAX (200) heat pump so that they can exchange energy, but there should never be excess heat, as they will have to be discharged to the external environment, which means a loss of efficiency. .

In order for the two cycles to work in "symbiosis" in the manner described, it is necessary that the energy cycle be able to capture all the heat that the UAX returns to it through its high temperature source (210).

For the reasons stated in the immediately preceding paragraphs, the preferred embodiment of the present invention relates to configuration 6, in which it is possible to extract a certain vapor stream from the element (112).

For the beneficial use of this steam flow generated in the element (112), according to this invention, within the energy cycle, there are three possible options:

A. Send this steam flow to the initial additional stage of the steam compressor (115), so that this steam is added to the steam flow from the element (114) to be compressed together and sent to the main heat source (101).

B. Send this steam flow to the superheater coil (136), which raises its temperature for subsequent expansion in an additional turbine (137), the outlet of which is connected directly to the inlet of the HPP turbine (127). In this case, this additional vapor flow circulating through the low pressure circuit is returned to the constituent main Rankine cycle through a bypass line after the pump (123).

C. Send one part of this steam flow in combination according to each of the options A and B above.

These three alternatives are shown in configuration 5 in FIG. 6.

SPECIFIC ADVANTAGES OF THE PLANT OF THE INVENTION

The fundamental advantages provided by the combined cycle of the present invention over other mechanical power generation methods are mainly as follows:

- With the energy cycle of the present invention, a performance is obtained that is as good or better than that offered today by other available methods in the known state of the art.

- With the energy cycle of the present invention, less environmental impact is obtained than that created by other available methods in the known state of the art.

The most advantageous individual features of the combined cycle of the present invention are as follows:

- In a combined energy cycle, water is used as a heat transfer medium common to all the equipment that forms it. This makes it possible that:

- The combined power cycle integrates at least one constituent Brayton cycle and one constituent main Rankine cycle into a single cycle. This makes it possible that:

- The combined energy cycle can operate both in a closed cycle and in a semi-closed cycle (internal combustion in oxygen).

- The combined energy cycle is regenerated using a heat pump. This makes it possible that:

- Combined energy cycle realizes the capture of CO ₂ (generated in the process of combustion in oxygen) as a concentrated gaseous or liquid residue, which is isolated in a special component of the cycle - element (107).

- When there is a CO ₂ liquefaction plant integrated into the plant and acting as element (107), the efficiency of the liquid CO ₂ production process is very high, since the heat generated in the successive CO ₂ compression steps, instead of being lost, is recovered by transferring it to the low temperature source (201) of the heat pump (UAX), which can be reused.

- Combined energy cycle (excluding direct losses and cogeneration heat) releases heat into the environment through a single thermal reservoir - the heat sink (128). The heat released by the rest of the elements is reused by some other element in the same cycle.

The integration of the absorption heat pump UAX (200) into the tail of the Brayton component cycle is a key and innovative element introduced by the combined cycle of this invention. The heat pump UAX (200), integrated into the energy cycle, achieves the following distinctive results, especially new and advantageous:

1) Increasing the overall efficiency of the energy cycle. The UAX (200) captures heat from the energy cycle at its low temperature source to recycle it through its high temperature source. This means that there is no heat loss from the heat transfer medium to the external environment during the isobaric cooling stage of the Brayton cycle component. This means that the condenser (128) acts as the only heat sink of the combined cycle through which heat is released to the outside.

2) Regeneration of the constituent Brayton cycle. This invention is a new "regeneration" method for the Brayton component cycle, according to which, with the help of thermal energy transmitted by the "heat pump" UAX (200), part of the steam of the energy cycle is regenerated.

3) Reducing the mechanical work of compression in the constituent Brayton cycle. In the energy cycle, UAX(200) achieves an effect equivalent to that of steam compression, since the heat transfer process performed by a heat pump involves the condensation of steam at ambient pressure (with heat absorbed by the "low temperature source") to later produce steam again at a higher temperature. pressure (with the release of heat "high temperature source") at another point in the same cycle.

4) Reducing the impact on the environment. In this invention, the carbon dioxide removal process is inherently due to the fact that the operation of the combined cycle itself gets rid of this combustion product gas at a specific point in the combined cycle - element (107). By integrating the heat pump UAX (200) into the semi-closed combined cycle of the present invention, complete condensation of the heat transfer medium (water) is achieved, leaving only CO ₂ free. With this method, the combined cycle of this invention does not release gases of any type from combustion directly to the atmosphere.

The overall effect achieved by connecting the heat pump UAX (200) to the constituent Brayton cycle is equivalent to the compression of its heat exchange gas in the sense that, starting from the gaseous fluid it contains at low pressure and temperature, a (regeneration) process is carried out which delivers the same gaseous fluid, but at a higher pressure and temperature. The key difference is that a heat pump is used instead of mechanical means to produce this pressurized fluid. The use of a heat pump to generate compressed steam further provides a clear environmental advantage over other hydrocarbon-based fuels of the state of the art, as it introduces the capture of non-condensable gases from combustion, the emission of which entails detrimental effects on the environment.

Provided the semi-closed oxygen combustion cycle uses fuels, CO ₂ will be produced which accompanies the water vapor until it is cooled by the low temperature source of the heat pump. All of this CO ₂ , which is obtained concentrated and in a gaseous state, is removed from the energy cycle when all the water vapor it contains condenses. The capture of CO ₂ generated in the combustors of the combined cycle occurs as a direct consequence of the operation of the cycle equipment, and in no case is there any special procedure for the "capture" of CO ₂ : that is, even if the capture of CO ₂ is not of interest for protection environment, the cycle would work in the same way and the captured CO ₂ could be released directly into the atmosphere. In this cycle, CO ₂ capture is an advantage and not an option.

This means that CO ₂ capture occurs naturally in the energy cycle as a direct consequence of the regeneration of the Brayton cycle component by the heat pump. With this method, no other additional procedure is needed to remove CO ₂ from combustion in this combined cycle.

SPECIFIC OPTIONS FOR CARRYING OUT THE PLANT OF THE INVENTION

In order to successfully maximize performance, it is necessary that the combined cycle of this invention contains a number of additional equipment.

In order to increase the overall efficiency of the combined cycle, combined cycles in accordance with FIG. 2, 3, and 4 basically provide four types of improvements over the main cycle shown in FIG. one:

1. Increase in pressure in the main heat source (101). This is achieved by increasing the pressure of the steam regenerated in the reboiler (113) and this involves one or more additional mechanical compression steps using certain compressors (115) and (117). This compression process is carried out in several stages with intermediate cooling, using an exchanger formed from elements (116) and (118).

- 2. Increasing the temperature of the steam entering the HPT turbine (122). This is achieved by providing an additional auxiliary heat source (132) which increases the enthalpy of the steam of the constituent main Rankine cycle.

- 3. Use of part of the heat contained in the exhaust gases from the WTT turbine (102) for industrial applications not related to the energy cycle. In this way, mechanical and useful thermal energy are obtained simultaneously in a process known as "cogeneration".

- 4. Reuse of part of the heat that is released on the heat sink. It is possible to successfully improve the performance of the combined cycle of this invention when the heat sink consists of a recovery circuit that generates steam in another secondary Rankine cycle at a lower pressure than the constituent main Rankine cycle. To achieve this, the present invention proposes four different types of configurations (represented in Fig. 2, 3, 4 and 6).

These four types of combined cycle improvements are fully compatible. However, with regard to the fourth type of improvements mentioned above, it should be noted that there are different methods of reusing the heat released by the main tap of the cycle - the capacitor element (128) shown in FIG. 1 - replacing it with a secondary Rankine cycle in such a way as to use part of the captured heat to convert it into work using the LPT turbine (127), and in such a way that the condenser of this secondary Rankine cycle continues to fulfill the mandatory role of "removal" for the heat of the combined energy cycle . There are four different combined cycle configurations, depending on how the secondary Rankine cycle is integrated. These three configurations correspond to FIG. 2, 3, 4 and 6, respectively. Each of these configurations consists of specific equipment and items detailed below, with the specifics of each configuration described separately.

To implement the first three types of improvements, the combined cycle of the present invention is designed to include a number of additional items of equipment. It is important to emphasize that the accessory equipment is that which does not form part of the main main cycle and is designed to work to implement different versions of the combined cycle that are more efficient and provide additional benefits over and above those provided by the basic configuration of FIG. one.

The fourth type of improvement mentioned above is based on the partial reuse of the heat released in the heat sink, in place of which the secondary Rankine cycle is contained. This invention provides for four types of configurations, depending on how the secondary Rankine cycle is integrated into the combined cycle. Each of these configurations requires its own additional hardware, as will now be described in detail.

The additional equipment constituting the different versions of the combined cycle according to this invention are as follows:

115: First steam compressor. This compressor (115) performs the first step of compressing the water vapor from the condensing element (114) of the heat exchanger. In addition, in cases where the design of the installation provides for it, it is possible that some of the steam generated in the element (112) is compressed in the first additional stage of the compressor (115). In this particular case, this first additional step in the compressor (115) is required because the pressure of this steam generated in this element (112) is always lower than the pressure of the steam entering the compressor (115) from the element (114).

The thermodynamic efficiency of the power cycle increases when the pressure in the WTT turbine (102) is increased, and this is achieved by increasing the pressure of the steam entering the main heat source (101). In order for the water vapor to reach the main heat source (101) at a higher pressure than the pressure of the steam generated in the reboiler (113), additional mechanical means can be used. To do this, a compressor (115) is provided, which increases the pressure of the water vapor leaving the side of the exchanger (114), applying mechanical work received from the transmission shaft (130) of the installation.

When the vapor is compressed, it raises the temperature (due to the Joule-Thomson effect), although the mechanical compression process is more efficient when the compressed gas is colder. The conclusion that follows from this is that the thermodynamic efficiency of the compression process is greater when it is carried out in several stages. For this reason, the vapor leaving the compressor (115) is sent to the heat exchange element (116) for cooling before the next compression step is performed.

Cooling exchanger for vapor between compression stages, consisting of elements (116) and (118):

116: Housing side of the cooling exchanger for vapor between compression stages. This element (116) together with the heat exchange element (118) forms a heat exchanger. The outlet vapor from the compressor (115) is cooled by circulation through the element (116) before passing to the next compressor (117) in order to improve the mechanical efficiency of this equipment. Inside it is a heat exchange element (118), through which the condensate obtained from the lower part of the element (114) circulates, serving as a coolant.

118: Cooling element for steam between compression stages. This heat exchange element (118) together with the heat exchange element (116) forms a heat exchanger. This heat exchanger (116/118) will always exist, provided there is a second compressor (117) in cascade with the first one (115). In case the unit does not have a compressor (117), an exchanger (116/118) is optional.

The heat exchange element (118) is a coil or any other heat exchange element through which water circulates, which serves as a refrigerant to cool the vapor between successive mechanical compression steps performed by compressors (115) and (117). The condensate pump (129) pushes the water that circulates through this heat exchange element (118) and the flow leaving it is sent to the main heat source (101).

117: Final steam compressor. It is another additional compressor connected in series with the previous compressor (115). This compressor (117) receives cooled steam from the element (116) and the steam leaves it at a pressure sufficient to feed the main heat source (101).

Obviously, it is also possible to compress the steam using only one steam compressor and carry out this operation in just one step. Therefore, there is an option not to use this additional steam compressor (117), but if it exists, it will always be connected in series with the compressor (115) after the intermediate refrigerant exchanger (116/118).

131: Auxiliary heat exchange element for preheating fuel and combustion aid (before they enter the combustion chambers). This is a set of pipes, a coil or other heat exchange element through which the auxiliary fluid circulates, optionally located, according to the specific design requirements of the installation, after some low pressure evaporation element (125) or inside the condensing heat exchange element (114), and from which it absorbs heat used to preheat separately both the fuel and the combustion support material above their supply conditions to a temperature at which they are sent to the oxy-combustion chambers.

Apart from being used to preheat fuel and combustibles of the combined cycle, the heat from the coil (131) may be destined for any other application independent of the power cycle, in which case and for all purposes it is referred to as "cogeneration".

132: Auxiliary heat source. When an auxiliary heat source (132) is available, it is located immediately after the set of tubes of evaporators and superheaters (121) for steam at the outlet of the RSC (103) and its task is to increase the enthalpy of steam in the constituent main Rankine cycle so that it enters the HPT turbine ( 122) with a higher superheat level.

When the combined cycle is "closed", the auxiliary heat source (132) consists of an additional heat exchanger that receives heat from an external source. When the combined cycle is "semi-closed", the auxiliary heat source (132) may be an additional oxygen combustion chamber that operates at a higher pressure than the main heat source (101).

133: Heat exchange element for cogeneration. It contains a tubular heat recovery circuit for use in external cogeneration applications outside the power cycle. Therefore, it works by circulating a fluid independent of the rest of the plant.

The heat exchange element (133) is an additional source of heat through which heat is released outside the combined cycle, but it is considered useful heat for industrial use. Indeed, it is believed that the thermal energy extracted from the energy cycle by the heat exchange element (133) exits at a temperature sufficient for its use in various types of conventional industrial processes, in a range that can be between 175°C and 600°C, depending from the installation project.

In some cases, depending on the pressure and temperature variables with which the cycle is designed, it is required that the heat exchange element (133) extract heat from the RAC (103) so that it can constantly establish the energy balance of the cycle (especially when the combined cycle has two sources heat).

In accordance with mandatory requirements related to the need to establish an energy balance, the amount of heat removed from the cycle in the form of cogeneration is determined by the needs of the combined cycle, and not by the heat demand from any external consumption equipment, unless there is some additional an internal system that allows him to modify his energy balance.

Regardless of whether or not there is a cogeneration coil (133) to extract heat from the RSC (103), the combined cycle of this invention may contain an "auxiliary heat rejection system" made of two additional pieces of equipment - the reheater (134) and the TSD turbine ( 135), - which are provided to establish an energy balance, which must be constantly maintained in the installation, reducing the amount of steam supplied to the heat sources (101) and (132), and consequently to the RKK (103). In other words, it is possible to reduce heat by modifying the internal functioning of the cycle, rather than by forced release of heat into the external environment.

The "auxiliary heat rejection system" is formed by a steam recovery device at the outlet of the HPT turbine (122), which circulates through the reheater (134), then through the TSD turbine (135) and finally re-introduces the outlet steam into the final section of the RKK (103).

The "auxiliary heat rejection system" is applied as a way to mitigate the energy imbalance that occurs during normal combined cycle operation or even load changes.

For certain design configurations, especially where two heat sources (101) and (132) are available, this equipment may become mandatory.

In the "auxiliary heat rejection system" one part of the water vapor belonging to the constituent main Rankine cycle is used as a working fluid, so that when it is present, it is considered part of it.

134: Auxiliary reheater of the constituent main Rankine cycle. The reheater (134) is located inside the RSC (103) itself and consists of a tubular circuit that heats the steam extracted from the outlet of the turbine (122) and immediately sends it to the TSD auxiliary turbine (135).

135: Auxiliary medium pressure turbine TSD component of the main Rankine cycle. The function of this steam turbine is to generate work after the cycle constituting the main Rankine cycle.

The TSD turbine (135) receives steam from the outlet of the HPT turbine (122) after it has been superheated in the reheater (134) to increase mechanical efficiency.

It is characterized by being a turbine that operates at a pressure lower than that of the VTT turbine (102) and higher than that of the LPT turbine (127), so that it is designated by its initial letters as TSD (medium pressure turbine). This turbine operates at back pressure, in other words, performs a partial expansion of the steam so that there is sufficient pressure at the outlet to introduce steam at some point in the RSC (103) (where the temperature of the steam entering the duct and the temperature of the gases circulating through channel match).

In order for certain high efficiency energy cycle designs to be able to work in conjunction with low efficiency UAX heat pumps, without having to pass on the losses to the outside, additional water vapor flow needs to exit the element (112) (at a pressure above atmospheric pressure).

Thus, the energy cycle can convert this amount of excess heat transferred to it by UAX into some amount of steam.

There is an option to send this steam generated in the element (112) directly to the compressor (115). This option does not require consideration of any additional equipment, but only the means to provide the compressor (115) with the means to perform the first additional compression step in order to equalize the pressure of the vapor coming from the element (114).

Configuration 2 and configuration 3 are the most appropriate for an oxy-combustion combined cycle project that uses other possible carbon-containing fuels in addition to hydrogen because their combustion generates carbon dioxide. The presence of this gas requires the secondary Rankine cycle to be independent of the rest of the power cycle, as the non-condensable gases prevent the "vacuum" pressures required for economical operation from being reached. In these combined cycle configurations containing an independent secondary Rankine cycle, it is possible that this Rankine cycle may use heat transfer media other than water, such as organic Rankine cycles (ORCs) that use organic fluids as the heat transfer medium. .

The steam generated in this independent secondary Rankine cycle always operates at a pressure lower than that of the component main Rankine cycle, since its temperature is very different. The steam produced in the secondary Rankine cycle drives the LPH turbine (127) and this provides additional work to the combined cycle transmission shaft (130). The steam leaving this HPP turbine (127) then passes into the condenser (128) which actually acts as a heat sink so that the resulting combined cycle loses energy to the outside. The condensate produced at the bottom of the condenser (128) is sequentially moved by the pump (123) to the economizer (124), evaporator (125) and superheater (126), after which it returns to the turbine (127) and thus closes the cycle. When the plant has a superheater (136) and a turbine (137) for the regenerated steam, there is a bypass line that returns this additional steam after the condensate pump (123) to feed the Brayton cycle and the main Rankine cycle.

Configuration 2

The installation of the present invention according to additional embodiments corresponding to configuration 2 shown in FIG. 2 is characterized as follows:

- It contains an independent secondary Rankine cycle that uses its own heat transfer medium, independent of the rest of the power cycle.

- The RKK recovery channel (103) operates at a pressure above atmospheric pressure.

- Steam condensation occurs in the terminal section of the RSC (103), where the temperature of the gases is lower.

The mode of operation of the installation according to configuration 2 consists mainly in providing an evaporator circuit belonging to an independent Rankine cycle in the interior of the recovery channel RKK (103). This evaporator circuit generates its steam with the help of heat from the condensation that occurs in the end section of the RSC (103), where the temperature is lower. The condensed water received at the bottom of this RKK (103) is sent to an external exchanger (108/124) where the heat contained in the condensate is transferred to the economizer (124) of the secondary Rankine cycle.

Configuration 2 includes all the elements of configuration 1 and, in addition, the following:

108: Shell side of the secondary Rankine economizer exchanger. The element (108) forms a heat exchanger together with an economizer (124). The heat exchange element (108) circulates the condensate collected either from the lower part of the RKK recovery channel (103) or from the lower part of the channel (105), in accordance with the project under consideration, transferring heat to the economizer (124) of the secondary Rankine cycle.

124: Rankine secondary cycle economizer. Together with the heat exchange element (108), it constitutes a heat exchanger. The economizer (124) is a secondary Rankine heat exchange element housed within the heat exchanger element (108) from which it receives heat by raising the temperature of the condensate (to bring it close to its boiling point), which it returns to the condenser (128) by promoting through the feed pump (123) of the secondary Rankine cycle.

123: Feed pump (low pressure) secondary Rankine cycle. This is the pump that moves the heat transfer medium from the condenser (128) to the economizer (124) of the secondary Rankine cycle.

125: Evaporator (low pressure) secondary Rankine cycle. This is the element of the heat exchanger provided, according to configuration 2, in the last section of the recovery channel (103), from which it receives the heat of condensation. Its task is to receive the fluid from the economizer (124) and convert it to steam for the secondary Rankine cycle.

When the plant is designed according to configuration 5, the evaporator (125) of the secondary Rankine cycle can be divided into two sections connected in parallel.

126: Superheater (low pressure) secondary Rankine cycle. This is a heat exchange element provided inside the recovery channel RKK (103) and whose task is to raise the temperature of the steam generated in the evaporator element (125) of the secondary Rankine cycle before it enters the LPH turbine (127).

127: Low pressure turbine (LPT) of the secondary Rankine cycle. This is a secondary Rankine turbine that transfers additional mechanical work to the transfer shaft (130). The LPH turbine (127) receives steam from the superheater (126) and the exhaust steam is sent to a condenser (128) which acts as a heat sink for the combined cycle.

Optionally, configuration 2 may include all of the elements mentioned above in the section titled "Specific Embodiments of the Installation of the Present Invention".

Configuration 3

The installation of the present invention according to further embodiments corresponding to configuration 3 shown in FIG. 2 is characterized as follows:

- It contains an independent secondary Rankine cycle that uses its own heat transfer medium, independent of the rest of the power cycle.

- The RKK recovery channel (103) operates at ambient pressure.

- In the RKK (103) there is no condensation of steam, unless an independent condensing channel (105) is provided for this purpose.

- It contains a fan (104) which extracts the gases from the RKK (103) and compresses them so that the condensate duct (105) operates at a higher pressure than the pressure at the outlet of the RKK (103).

The fundamental difference compared to configuration 2 is that in its operation in configuration 3, the recovery channel of the RKK (103) operates at a lower pressure (generating more work on the turbine VTT (102) and making the temperature of the gases at the inlet of the RKK (103) lower ) and then, by means of a fan (104), the gases leaving this channel are compressed to increase the condensation temperature of the steam and thus increase the operating pressure of the secondary Rankine cycle. By successfully transferring heat at a higher temperature to the secondary Rankine cycle, this increases the mechanical work generated by the LPH turbine (127).

This configuration 3 includes, in addition to all the elements contained in configuration 2, the following:

104: Fan. It is a suction fan located at the gas outlet of the recovery duct (103), which separates the condensation zone of the RKK recovery duct (103) into an independent condensate duct (105). The fan (104) produces an increase in the pressure of the steam drawn in by the RAC (103) by raising the saturation temperature of this steam. This increase in steam saturation temperature on the channel (105) side means that secondary Rankine cycle steam can be generated at a higher temperature, resulting in increased efficiency.

Provided that the plant has a fan (104), the evaporator (125) of the secondary Rankine cycle can be divided into two sections operating in parallel, one of which is located in the channel (105) and the other in the channel (103) after the economizer (120) . This design alternative is possible in any of configurations 2, 3 and 5, although it is only present in configuration 5 (FIG. 6).

105: Independent condensate duct. This is the section of the recuperation channel, in which the water vapor contained in the gas phase leaving the RAC (103) and propelled by the fan (104) condenses.

Unlike what happens in configuration 2, in configuration 3 the evaporator (125) belonging to the secondary Rankine cycle is located inside the section of the condensing channel (105), through which the heat of condensation is exchanged to generate steam of the secondary Rankine cycle.

When the cycle is designed according to configuration 5, the evaporator (125) consists of two sections working in parallel: one in the channel (103) and the other in the channel (105).

Configuration 4

The installation of the present invention according to additional embodiments, corresponding to configuration 4 shown in figure 4, is characterized by the following:

- It contains a secondary Rankine cycle that uses a heat transfer medium that is shared with the rest of the power cycle.

- The secondary Rankine cycle has no economizers, evaporators or superheaters.

- The heat sent to the LPH turbine (127) is obtained directly by extracting it from the recovery channel of the RKK (103).

- The condensate obtained from the secondary Rankine cycle is used directly as feed water for the rest of the combined cycle.

Configuration 4 is a design simplification of the combined cycle in which the steam circulating through the combined cycle is also used as secondary Rankine cycle fluid, which is possible, always provided that no CO ₂ or other non-condensable gases are present at any point in the combined cycle. This only happens when the plant is designed to operate in a closed cycle and when hydrogen is the only possible fuel.

It should be noted that hydrogen can be used as fuel in any of the possible combined cycle configurations, but when hydrogen is used as the only fuel, this design version (as shown in Fig. 1) is preferred because it is simpler and can be more efficient.

In this 4 power cycle configuration, the secondary Rankine cycle operates with the same fluid as the rest of the combined cycle. The steam of the secondary Rankine cycle according to this configuration 4 is obtained from the flow extracted directly from the channel RKK (103), which is sent directly to the turbine LPT (127) of the secondary Rankine cycle, and on the other hand, the condensate obtained from the condenser (128) is returned directly to feeding the rest of the combined cycle using a pump (109). A direct consequence of this is that in this design version there are no heat exchange elements generating their own steam: that is, no economizer (124), no evaporator (125), no superheater (126).

This configuration also does not include the feed pump (123) of the secondary Rankine cycle, since the pump (109) returns condensate directly from the condenser (128) as feed water for the rest of the combined cycle.

When the semi-closed cycle is implemented using hydrogen as a fuel in accordance with configuration 4, water is the only combustion product and is removed from the cycle in liquid form from this condensate return line (same as in other configurations).

When the closed cycle is implemented according to the configuration 4, there are no combustors that continuously supply the substance to the combined cycle, and therefore also no type of residue is continuously obtained from it.

In light of this, the only combined cycle equipment through which CO ₂ can be circulated is:

When the main heat source (101) consists of a combustion chamber (some fuel other than H ₂ ): the combustion chamber (101) itself, the VTT turbine (102), the RKK (103), the condensing exchange element (106) and, finally, the element (107), from which CO ₂ is removed from the cycle.

When there is another combustion chamber in the power cycle playing the role of an auxiliary heat source (132), in addition to all the equipment listed earlier, CO ₂ is circulated through the auxiliary combustion chamber (132), HPT turbine (122), reheater (134) and the TSD turbine (135), considering that the power cycle may also include the last two optional elements.

When the power cycle is implemented according to configuration 3, in addition to the above equipment, there is CO ₂ circulation through the fan (104) and the condensing exchange element (105).

According to a further alternative, this steam generated in the element (112) can be transferred to the secondary Rankine cycle to be eventually expanded in the LPT turbine (127).

This capability corresponds to additional embodiments with configuration 5 shown in FIG. 6,

Configuration 5 is the preferred embodiment of this invention because it is the most complete and contains all the elements that make up this invention, whether those elements are considered mandatory or optional. It allows you to implement both closed and semi-closed cycles using any kind of fuel that can be used in other configurations.

Configuration 5 contains all the elements of configuration 3 and additionally requires two special pieces of equipment:

136: Superheater for steam generated in element (112). This element (136) consists of a coil located inside the RSC (103) which receives saturated steam from the element (112) and whose task is to raise its temperature so that it can then expand in another turbine (137) before entering the secondary Rankine cycle.

137: Turbine for steam generated in element (112). This turbine (137) consists of an additional turbine, the outlet steam pressure of which corresponds to the pressure and temperature of the steam entering the LPT turbine (127). As it expands in the turbine (137), the steam generates additional work, which is transferred to a common transmission shaft (130) and the output of this turbine is connected to the inlet of the LPT turbine (127) to continue expansion along with the secondary Rankine cycle steam from the superheater (126 ).

To establish the necessary balance of matter, each time additional steam is introduced into the secondary Rankine cycle, it is required that there be a bypass line in the pump discharge line (123) that returns this flow to feed the constituent main Rankine cycle in the form of water in the liquid state.

In all cases in which the plant has a superheater (136) and a turbine (137) for regenerated steam, there is a bypass line to the suction port of the pump (109) after the discharge line of the pump (123) for condensate.

To operate the compressor (115) according to this configuration 5 shown in FIG. 6, this compressor (115) needs to have an additional first compression stage to increase the pressure of the vapor entering it from the element (112) and equalize it with the pressure of the vapor entering the compressor (115) from the element (114).

The installation according to the present invention, whatever its design configuration, can be energetically connected to the external environment only through:

- sources (101) and (132) of heat, as the only possible points of energy entry into the combined cycle;

- points where energy leaves the cycle, in addition to the inevitable direct losses: heat escaping through the outlet (128), useful mechanical work obtained from the transfer shaft (130) and useful heat obtained for "cogeneration".

DETERMINATION OF THE MAXIMUM THEORETICAL CAPACITY OF THE UNIT OF THE INVENTION IN A SEMI-CLOSED CYCLE

The maximum theoretical capacity of a plant generating useful energy from thermal energy from a fuel type according to the present invention can be estimated very simply and approximately using the following method:

As an example, the calculation of the theoretical cycle productivity of the present invention, which uses only pure hydrogen as a fuel, is performed taking into account the following considerations:

- it is considered that the "useful energy" produced by the installation is the sum of the heat received from the RKK (103) for application external to the cycle, in the form of "cogeneration" through the element (133), and the useful mechanical work leaving the combined cycle through its transmission shaft (130);

- it is believed that there are no "direct losses" and the combined cycle loses thermal energy only through the condenser (128), which performs the function of a heat sink;

- calculations are made for 1 kg of condensate in the return line, where:

- "X" specific fuel: the amount of kg of fuel burned for every 1 kg of "return condensate" of water that is returned to the cycle after the vacuum condenser (128);

- "PCS" the highest calorific value of H ₂ , the value of which is assumed to be 142,200 kJ/kg;

- "PCI" is the lowest calorific value of H ₂ , the value of which is assumed to be 120 240 kJ/kg;

"PCS _H2O " is defined as the highest calorific value of a specific fuel (for every 1 kg of water generated), assuming that in the combustion reaction, for every 1 kg of H ₂ burned, 9 kg of H ₂ O are formed stoichiometrically, so that:

PCS _H2O = 15800 kJ/kg _{generated H2O}

PCI _H2O = 13,360 kJ/kg _{generated H2O}

"ΔH _VC " is defined as the specific enthalpy jump of steam condensation in the heat sink (128), given the calculation for a fictitious theoretical condenser realizing the enthalpy jump of steam condensation, coinciding with the difference between PCS _H2O and PCI _H2O , then:

ΔH _VC = PCS _H2O - PCI _H2O = 2440 kJ/kg _H2O

"M _V " is defined as the amount of "condensed" steam in the heat sink (128); this amount will be equal to 1 kg of water returned to the cycle, plus the amount of water formed by burning H ₂ (X) that must be removed from the cycle:

M _V = 1 + X (kg _H2O )

"Energy loss" is defined as the energy removed in the capacitor (128):

Energy loss = M _V * ΔH _VC = (1 + X) * (ΔH _VC ) = (1 + X) * (PCS _H2O - PCI _H2O )

Energy loss = (1 + X) * 2440 kJ/kg _H2O

The “useful energy” of a cycle is determined taking into account the fact that “the energy entering the cycle is equal to the energy leaving the cycle”.

Useful energy = Combustion energy - Heat removed in the outlet (128)

Useful energy (kJ/kg _H2O ) = (X * PCS _H2O ) - 2440 * (1+X) = X * (PCS _H2O - 2440) - 2440

Useful energy (kJ/kg _H2O ) = (X * PCI _H2O ) - 2440

The performance of the installation "η _PCS " relative to PCS is determined from the equation:

=

η _PCS =

=

-

*

η _PCS =

-

*

Replacing PCS _H2O and PCI _H2O with their numerical values:

-

*

η _PCS =

-

*

_ηPCS = 0.8456 - 0.1544*

The performance of the "η _PCI " installation relative to PCI, which is usually used as a reference, is given by the expression:

=

n _PCI =

=

-

*

η _PCS =

-

*

Replacing PCI _H2O with its numerical value:

*

n _PCI =

*

η _PCS = 1 - 0.01826 *

The two final equations for performance η _PCS and η _PCI give a very approximate result for the performance of the combined power cycle of the present invention. Although it is true that they are not strictly precise, these expressions lead to the following conclusion: the productivity of the combined cycle of the present invention varies with the specific fuel burned. That is, the productivity of the cycle increases when the specific fuel consumption in the cycle increases.

However, it is not possible to increase specific fuel consumption unless a number of fundamental thermodynamic constraints are met, which are directly imposed on the combined cycle.

One of these fundamental limitations is that the combined cycle must comply with the principle of conservation of energy, according to which the energy entering the combined cycle is always equal to the energy leaving it. According to this principle, an increase in specific fuel consumption may mean, depending on the design parameters of the power cycle, an excess of thermal energy that cannot be captured by the evaporator and superheater (121) of the component main Rankine cycle, in which case it will be necessary to provide some way to remove heat to the external environment and/or some way to reduce the heat input to the RSC (103).

Some of the combined cycle embodiments described earlier, which must necessarily remove one part of the heat to the outside of the combined cycle, may contain a heat exchange element (133) to perform this function of removing heat to the external environment, but do so at a temperature sufficient to make it applicable to meet the heat demand of certain industrial processes, thus representing the "cogeneration" procedure.

In some situations where it is imperative to reduce heat input to the RSC (103), which may occur especially during transients or load changes, power cycle configurations may include a “steam dump system” at the outlet of the HPT turbine (122), which reduces the amount of steam entering the sources (101) and (132) of heat, and hence entering the RKK (103). Such a steam dump system includes an intermediate superheater (134) and an auxiliary turbine TSD (135), whose output steam is finally introduced at some point in the terminal section of the RSC (103). It should be noted that this system for venting steam to heat sources does not represent any improvement on the mechanical performance of the combined cycle, although it can be very useful in allowing modulation and load changes in the plant and, in addition, it allows certain combined cycle design configurations. with double heat source and very high usable energy output.

Claims (95)

1. Installation for generating mechanical energy using a combined energy cycle, containing at least: - means for realizing a closed or semi-closed regenerative component of the Brayton cycle, in which water is used as a heat transfer medium, - means for realizing at least one Rankine cycle constituting the main Rankine cycle interconnected with the regenerative constituent Brayton cycle, and - a heat pump (UAX), which forms a closed circuit that regenerates the regenerative component of the Brayton cycle. 2. Installation for generating energy according to claim 1, characterized in that it contains the main source (101) of heat, which is selected from: - heat exchanger and - combustion chambers with combustion in oxygen, such that in said main heat source (101) the fluxes from two cycles constituting the Brayton and constituting the main Rankine converge together. 3. Installation for generating energy according to claim 1, characterized in that the Brayton regenerative cycle is semi-closed, with combustion in oxygen and natural capture of CO ₂ . 4. Installation for generating mechanical energy according to any one of the preceding paragraphs, characterized in that it also contains: - element (107) selected from: - a regeneration condenser, through which the unit transfers energy to the low temperature source (201) of the heat pump UAX, which condenses in one simple step, and - a CO ₂ liquefier which receives work from the transfer shaft (130) and condenses the gases in several stages and only transfers the heat generated in the successive compression stages of this CO ₂ liquefier to the low temperature source (201) UAX, - a reboiler (113) with which heat is returned to the energy cycle from a high-temperature source (210) of the heat pump UAX, - a pump (111) for the regeneration condensate, which drives the condensate obtained in the lower part of the regeneration condenser (107) and makes it flow to the reboiler (113), - recovery channel (RCC) (103), which generates water vapor, - at least two turbines, one of which is a HPT high-pressure turbine (122), which directs water vapor to the main heat source (101), and the other turbine (102) is a high-temperature HTT, which directs steam to the recovery channel (103 ), - at least one common transmission shaft (130), from which the useful mechanical energy of the cycle is obtained, - a system that performs the function of discharging heat by condensing steam in the lower part of the RKK (103) or after it, - condensate return pump (109), - feed pump (119) for the component main Rankine cycle, - steam generator for the constituent main Rankine cycle, consisting of: - economizer coils (120), - evaporators and superheaters for steam (121) located inside the recovery channel (103), - one condensing element (106) for heat exchange, before the entry of steam and gases into the regeneration condenser (107), which gives off heat to the condensate return heater (110), - one condensing element (114) heat exchange, provided at the outlet of the reboiler (113), which gives off heat to the element (112), selected from: - a heater (112) for supplying water to the reboiler itself (113) - and a recovery exchanger (112) which, in addition to preheating the feed water for the reboiler (113) itself, heats the feed water for the pump (119) and generates steam which is sent: - to the compressor (115) and/or - to the turbine (137) after increasing its temperature in the superheater (136), - one bypass line that connects the component Brayton cycle to the component main Rankine cycle, located between the discharge line of the pump (111) for the regeneration condensate and the intake channel of the feed pump (119). 5. Installation for generating energy according to any of the previous paragraphs. 1-4, characterized in that the energy cycle is semi-closed using combustion in oxygen in the case of using carbon-containing fuels, which contains: - an outlet for CO ₂ produced by combustion, located in the element (107), and - outlet for liquid water produced by combustion in the condensate return line from the bottom of the boiler. 6. Installation for generating energy according to any of the previous paragraphs. 1-4, characterized in that the energy cycle is closed or semi-closed, uses combustion in oxygen in the case when hydrogen is used as the only fuel, the heat removal consists of a secondary Rankine cycle with the same fluid as in the rest of the energy cycle, being interconnected with the installation through the discharge line of the condensate return pump (109) and through the line that reaches the recovery channel of the RKK (103). 7. Power generation plant according to any one of the preceding claims, characterized in that it comprises an element for supplying additional heat (132) located between the terminal superheater (121) and the turbine (122). 8. Power generation plant according to any one of the preceding claims, characterized in that it also contains one steam compressor (115) or several steam compressors (117) connected in series, which are located at the steam outlet of the exchanger element (114) and before the inlet steam hole to the main heat source (101). 9. Power generation plant according to any one of the preceding claims, characterized in that it also comprises a refrigeration exchanger (116/118) for steam between compressors (115) and (117) connected in series. 10. Power generation plant according to any one of the preceding claims, characterized in that it also contains, in the line for condensate from the bottom of the condensing element (114) of the exchanger, a return line to the reboiler (113), through which part of this condensate is sent to itself reboiler. 11. The power generation plant according to any one of the preceding claims, characterized in that it also comprises a heat exchange element (133) for cogeneration provided inside the recovery channel (103) from which it extracts useful thermal energy that can be destined for external use in industrial applications of any kind. 12. A power generation plant according to any one of the preceding claims, characterized in that it also comprises an "auxiliary heat rejection system" formed by: - an intermediate superheater (134) of the steam, which receives steam extracted from the HPT turbine (122), and - auxiliary turbine TSD (135), the output steam of which is introduced at some point of the terminal section of the RSC (103). 13. Installation for generating energy according to any of the previous paragraphs, characterized in that it further comprises: - a fan (104) that takes the exhaust vapors from the recovery channel of the RKK (103) and compresses them to send them to the condensate exchanger (105) containing at least one component section of the evaporator (125) of an independent secondary Rankine cycle. 14. Installation for generating energy according to any of the previous paragraphs, characterized in that it further comprises: - a heat exchanger (108/124), in which the condensate from the channel (105) is cooled on the casing side (108) and inside which the economizer (124) of the independent secondary Rankine cycle is located. 15. Installation for generating energy according to any one of the preceding claims, characterized in that the heat pump UAX (200) contains: - the main generator (201) of gaseous ammonia, acting as a low-temperature source, which exchanges heat only with the element (107), - a secondary generator (202) which receives the liquid phase from the ammonia absorber (210) and sends ammonia vapor to some compressors (203), while the remaining ammonia solution is sent to the main generator, - at least two ammonia compressors (203), connected in series, with intermediate cooling, which receive ammonia from the main (201) and secondary generators (202), - a compressed ammonia condenser (207), which receives the ammonia compressed and cooled in the supercritical ammonia evaporator (209) and transfers heat to the secondary generator (202), - evaporator (209) of supercritical ammonia, - a pump (208) for ammonia condensate from the compressed ammonia condenser (207), which pumps it into the ammonia evaporator (209), where ammonia vapor is produced at supercritical pressure, - ammonia absorber (210), which receives steam from the evaporator (209) of supercritical ammonia and dissolves it in the aqueous phase, and - a transfer pump (215) which pumps the dilute ammonia solution from the main generator (201) to the absorber (210). 16. Installation for generating energy according to any one of the previous paragraphs, characterized in that the heat pump also contains: - a heat exchanger (213/214) between the diluted ammonia solution from the main generator (201) and the concentrated ammonia solution from the absorber (210), - a coil (211) placed inside the ammonia evaporator (209), which uses the heat contained in the concentrated ammonia solution from the absorber (210) to produce supercritical ammonia, - a cooling coil (206) for the compressed ammonia from the compressors (203) which provides heat to the supercritical ammonia evaporator (209). 17. The method of generating energy based on a combined cycle, which is implemented using the installation according to any of the previous paragraphs. 1-16. 18. The method according to the previous paragraph, characterized in that it includes: - implementation of a component Brayton cycle, closed or based on combustion in oxygen, regenerated by the action of a heat pump (UAX), which uses water as a heat transfer medium and which produces mechanical energy in a high-temperature turbine (102), - implementation of the constituent Rankine cycle, interconnected with the above Brayton cycle, which exchanges matter and energy with it, and in which both water is used as a common heat transfer medium, and produces mechanical energy on the HPT turbine (122), - the use of a heat pump UAX (200) which exchanges energy with the constituent Brayton cycle in order to regenerate it and consume mechanical energy in certain compressors (203). 19. The method according to claim 17 or 18, characterized in that the water vapor circulating through the element (107) is completely condensed due to heat transfer to the low temperature source UAX (200), leaving only non-condensable CO ₂ in the gaseous residue in the case when in The cycle uses fuels other than hydrogen. 20. The method according to any one of paragraphs. 17-19, characterized in that it includes: - condensation in the element (107): - water vapor at ambient pressure, giving off the received heat to the low-temperature source (201) of the heat pump UAX (200), or - condensation of water vapor and CO ₂ , giving off the received heat to the low-temperature source (201) of the heat pump UAX (200), - and recovering the water vapor in the reboiler (113) at a higher pressure than that at which it was condensed in the element (107), using the heat provided by the high temperature source (210) of the heat pump UAX (200). 21. The method according to any one of paragraphs. 17-20, characterized in that the regeneration of the Brayton component cycle is performed by the action of the heat pump UAX (200), recirculating the heat of condensation of the steam at the temperature of the low-temperature source, in order to then return it to the cycle, by means of a high-temperature source, in order to regenerate water vapor at higher pressure and temperature than those at which it was previously condensed. 22. The method according to any one of paragraphs. 17-21, characterized in that it includes: - providing external energy from the main heat source (101), which is a pressurized combustion chamber in the case of a semi-closed cycle or a heat exchanger in the case of a closed cycle. 23. The method according to any one of paragraphs. 17-22, characterized in that, without taking into account direct losses, it includes the use of a single heat sink, through which the cycle transfers heat to the external environment. 24. The method according to claim 23, characterized in that the capacitor (128) of the independent secondary Rankine cycle performs the function of a heat sink. 25. The method according to any one of paragraphs. 17-24, characterized in that it includes the use of a recovery channel (103), in which the remaining heat from the outlet of the WTT turbine (102) is used to generate superheated steam of the constituent main Rankine cycle. 26. The method according to any one of paragraphs. 17-25, characterized in that it includes: - the implementation of a combined cycle with combustion in oxygen, which uses liquid or gaseous fuels with the general formula C _x H _y O _z , pure or mixed, where x, y and z take values \u200b\u200bthat correspond to real chemical compounds that can burn in the presence of oxygen. 27. The method according to any one of paragraphs. 17-26, characterized in that it includes reducing the amount of steam supplied to the heat source (101), or heat sources (101) and (132), by means of an "auxiliary heat rejection system" consisting of an intermediate superheater (134) and a turbine TSD (135), in such a way that the exhaust steam is extracted from the HPT turbine (122), thereby reducing the amount of heat entering the RKK (103). 28. The method according to any one of paragraphs. 17-27, characterized in that it includes preheating the water entering the reboiler (113) by means of the element (112) using the heat from the steam condensation occurring in the element (114). 29. The method according to any one of paragraphs. 17-28, characterized in that it includes increasing the pressure of the steam supplied by the element (112) and the pressure of the steam from the reboiler (113) and which exits the condensing exchange element (114) using additional mechanical compressors (115) and (117), cascaded, intercooled, and configured to provide sufficient pressure to send this steam to the main heat source (101). 30. The method according to any one of paragraphs. 17-19, characterized in that it includes: - in the case when the combined energy cycle is implemented as a closed one or burns only hydrogen, the steam is sent directly from the recovery channel (103) to the LPT turbine (127) of the secondary Rankine cycle, which operates under vacuum conditions provided by the condenser (128), from where the condensate is returned as feed water to the constituent main Rankine cycle. 31. The method according to any one of paragraphs. 17-30, characterized in that it includes drawing in exhaust gases from the channel (103), compressing them using a fan (104) and sending them to the condensing element (105) of the heat exchanger, thereby generating steam in the evaporator (125) of the secondary Rankine cycle. 32. The method according to any one of paragraphs. 17-31, characterized in that: - the heat pump UAX (200) is a refrigeration machine that operates through a combination of compression and absorption operations, using NH ₃ as the heat transfer medium and water as the solvent, - the main generator (201) of the heat pump UAX (200) performs the function of a low-temperature source, absorbing heat only from the element (107), - the only low temperature heat pump source UAX (200) operates at temperatures between 80°C and 120°C, - the ammonia absorber (210) of the UAX heat pump (200) acts as a high temperature source, transferring heat only to the reboiler (113), - in the heat pump UAX (200) NH ₃ vapor is compressed, in successive stages with intermediate cooling, - the compressed ammonia vapor condenser (207) of the heat pump UAX (200) releases all the heat released by the secondary generator (202), and - the supercritical ammonia evaporator (209) of the heat pump UAX (200) generates supercritical NH ₃ using heat, - supplied to it by cooling elements (204) and (206) for compressed ammonia between the compression stages, and - part of the latent heat contained in the concentrated solution, which comes hot from the ammonia absorber (210).

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