KR100728413B1 - Integrated gasification combined cycle power plant with kalina bottoming cycle - Google Patents

Abstract

The vaporized combined cycle generator is combined with a kalina bottoming cycle. The thermal energy streams 31, 69, 169 from the vaporization systems 48, 50, 52 are provided in heat exchange relationship with the working fluid mixture of the Kalina cycle, thereby heating the gas turbine exhaust gas 28 for heating the working fluid for the steam turbine. Replenishes the heat energy from The heat recovery fluid from the cold section 50b flows through the heat exchanger 27 with the condensed working fluid from the evaporation / condensation system to preheat the working fluid for the steam generator 12 and from the hot section 50a. The heat recovery fluid passes through heat exchangers 23 and 65 with the working fluid in the middle.

Description

INTEGRATED GASIFICATION COMBINED CYCLE POWER PLANT WITH KALINA BOTTOMING CYCLE}

The present invention relates to a generator, and more particularly to a method of using a Kalina bottoming cycle in an integrated gasification combined cycle (IGCC) generator.

Integrated gasification combined cycle power plants have obvious low cost, improved reliability and improved efficiency. The integrated gasification combined cycle process follows two stage combustion with a clean-up between each stage. The first stage has a vaporizer for partial oxidation of fossil fuels such as coal or heavy oil, while the second stage utilizes a gas turbine combustor for fuel gas combustion produced by the vaporizer to complete the combustion process. For example, inherent fuel processing losses associated with the vaporization of fossil fuels in conjunction with combined cycles have proven to yield good cycle efficiency. A simple combined cycle power generation system is provided with one gas turbine, one or more steam turbines, one or more generators, and a heat recovery steam generator (HRSG). Gas turbines and steam turbines can be combined in a tandem array into a single generator, or in separate steam turbine generator units for one or more gas turbines, generators and heat recovery steam generators to supply steam through a common header. A multi-shaft combined cycle system may be provided. In a combined cycle, heat from the gas turbine exhaust gas is provided to heat the steam turbine in heat exchange relationship with the working fluid in the heat recovery steam generator to generate power and mechanical work.

Recently, using a combination of multi-component working fluids and absorption, condensation, evaporation and recuperative heat exchange operations, losses typically inevitable in conventional Rankine cycles There was a significant improvement in the thermodynamic cycle by reducing In general, the improved thermodynamic cycles are known as Kalina cycles and provide a demonstrable and significant improvement in thermodynamic cycle efficiency. Kalina cycles use two subsystems that interact. The first subsystem includes a heat absorption process of the multi-component working fluid, including, for example, preheating, evaporation, superheating, generating feed heating and power generation. The second subsystem consists of a distillation / condensation subsystem (DCSS). The improvement in the efficiency of the Kalina cycle over the Rankine cycle is achieved using a component working fluid, preferably ammonia / water mixture, via a boiling point over the same pressure. Since the composition of the vapor and liquid streams varies at different temperatures throughout the cycle, the subsystem is responsible for the enthalpy of the working fluid and the heat sink used to condense the working fluid and the heat source used to evaporate the working fluid. The enthalpy-temperature characteristics can be made more similar.

In the heat absorption subsystem, the kalina system eliminates inconsistencies between the heat source and enthalpy temperature characteristics of the working fluid as it passes through the boiler. This energy loss typical in the Rankine cycle is reduced by taking advantage of the varying temperature enthalpy properties of the multicomponent working fluid upon evaporation.

In the second subsystem, the evaporation / condensation subsystem of the Kalina cycle, the spent working fluid after expansion through the turbine is too low in pressure and too high in ammonia concentration to condense directly at the temperature of the useful coolant. Thus, the working fluid is only partially condensed, and the lean solution is mixed with the precondensed two-phase flow from the recuperative heat exchanger, whereby a low condensation can be achieved at a useful refrigerant temperature. Form a concentration of ammonia / water mixture. Thus, the lean condensate recovers evaporatively to the turbine exhaust, regenerating the working composition for the heat absorption subsystem. Kalina cycles are disclosed in US Pat. Nos. 4,586,340, 4,604,867, 5,095,708, and 4,732,005, which are incorporated herein by reference. Ongoing exploration for increased efficiency in the power plant has resulted in the incorporation of a kalina bottoming cycle into the integrated gasification combined cycle power generation system according to the present invention.

Summary of the Invention

The present invention combines an integrated gasification combined cycle power generation system with a kalina bottoming cycle to provide increased power production and system efficiency. In particular, the present system uses a vaporization system having a vaporizer having a gas cooling device and a cleanup device. The power unit of the system includes a gas turbine, a heat recovery steam generator device having a kalina cycle bottoming device, and an optional air separation unit. Basically, the present invention utilizes a thermal energy stream discharged from a vaporization system and / or an optional air separation unit to heat the working fluid in a kali na bottoming cycle apparatus at a suitable location to replenish the thermal energy supplied from the gas turbine exhaust. This maximizes the overall benefit of the heat stream, which in turn improves the net power yield and thermal efficiency of the power plant. In an embodiment of the present invention, heat useful from the high temperature cooling section of the vaporization system is recovered and located in a heat exchange relationship with the multi-component working fluid of the combined cycle, thereby increasing the thermal energy supplied to the working fluid by the gas turbine exhaust gas. . It is also used to preheat the condensed multi-component working fluid prior to feeding the low temperature cooling working fluid of the vaporization system to the heat recovery steam generator.

In a preferred embodiment according to the invention, the integrated gasification combined cycle power generation system comprises a plurality of gases including first and second steam turbines and gas turbines for driving one or more generators to generate electrical power or mechanical work. A method of operating an integrated gasification combined cycle power generation system comprising a turbine and a fuel vaporizer for producing fuel gas for a gas turbine, the method comprising: (a) generating fuel gas from the fuel vaporizer; and (b) the fuel vaporizer. Supplying a heat recovery fluid from the gas, (c) supplying the fuel gas from the fuel vaporizer to the combustor for the gas turbine to drive the gas turbine, and (d) a working fluid through the first steam turbine (E) reheating the expanded working fluid from the first steam turbine; (f) expanding the working fluid reheated through the second steam turbine, (g) condensing the working fluid discharged from the second steam turbine, and (h) condensing the working fluid discharged from the second steam turbine; Passing a heated working fluid to the first and second steam turbines in a heat exchange relationship with a hot exhaust gas from a gas turbine, and (i) passing the working fluid in a heat exchange relationship with a heat recovery fluid. Additionally heating the working fluid supplied to the first steam turbine and the second steam turbine.

In a preferred embodiment according to the invention, the integrated gasification combined cycle power generation system comprises a plurality of first and second steam turbines and gas turbines for driving one or more generators for generating power or mechanical work. A method of driving an integrated gasification combined cycle power generation system comprising a gas turbine and a fuel vaporizer for generating fuel gas for a gas turbine, the method comprising: (a) generating fuel gas from the fuel vaporizer; Supplying a heat recovery fluid from a vaporizer, (c) supplying the fuel gas from the fuel vaporizer to the combustor for the gas turbine to drive the gas turbine, and (d) operating through the first steam turbine Expanding the fluid, and (e) reheating the expanded working fluid from the first steam turbine. The system, (f) expanding the reheated working fluid through the second steam turbine, (g) condensing the working fluid discharged from the second steam turbine, and (h) condensing Passing a working fluid in a heat exchange relationship with a hot exhaust gas from a gas turbine to flow a heated working fluid to the first and second steam turbines; and (i) exchanging the used working fluid with the heat recovery fluid. Heating the used working fluid discharged from one of the first and second steam turbines by passing through a furnace.

In yet another preferred embodiment according to the present invention, an integrated gasification combined cycle power generation system includes (i) a first steam turbine and a gas turbine operatively coupled with one or more generators to generate power or mechanical work. A method of operating an integrated gasification combined cycle power generation system comprising a plurality of turbines, (ii) an evaporation / condensation subsystem, and (iii) a fuel vaporizer for producing fuel gas for a gas turbine, the method comprising: (a) said fuel vaporizer; Generating fuel gas from the fuel vaporizer; (b) supplying a heat recovery fluid from the fuel vaporizer; and (c) supplying the fuel gas from the fuel vaporizer to the combustor for the gas turbine to drive the gas turbine. (D) an operation consisting of a mixture of different components having different boiling points at the same pressure through the first steam turbine Expanding the fluid, generating a used stream of the mixture of different components, (e) condensing the used stream in the subsystem, and (f) evacuating the condensed working fluid from a gas turbine Passing the heated working fluid to the first steam turbine and the second steam turbine in a heat exchange relationship with the gas; and (g) heating the working fluid by passing the working fluid in a heat exchange relationship with the heat recovery fluid. Steps.

Therefore, the main object of the present invention is to provide an integrated gasification combined cycle power generation system using a kaliona bottoming cycle to increase power production and efficiency.

1 illustrates a method using a thermal energy flow of a vaporization system using a thermal energy stream from a vaporization system to heat a working fluid of a kalina bottoming cycle and supplement the thermal energy provided to the working fluid by a gas turbine exhaust gas. Schematic of an integrated gasification combined cycle power generation system using a Kalina-type bottoming cycle.

Referring to FIG. 1, an integrated gasification combined cycle power generation system using a kalina bottoming cycle is shown. The system has a generator (G), a gas turbine (GT) and a steam turbine of the first high pressure (HP), the second medium pressure (IP) and the third low pressure, all of which are coupled to one or more generators (G). To generate electrical power or, optionally, mechanical work. A kalina bottoming cycle, ie a thermodynamic cycle, is provided with the high pressure (HP), medium pressure (IP) and low pressure (LP) steam turbines, preheater 14, evaporator 16, reheater 18 and superheater 20. A heat recovery vapor generator (HRVG), such as boiler 12, and a distillation / condensation sub-system (DCSS). A power generation preheater 21 and / or heat exchanger 23 is provided which heats the working components in the HRGV as well as auxiliary components via the combined cycles described below using work from fuel gas. As can be appreciated from the references above for the Kalina cycle, the multicomponent working fluid mixture utilizes one comprising a lower boiling point fluid and a relatively higher boiling point fluid. For example, an ammonia / water mixture may be used, but the mixture may be used by those skilled in the art.

As shown, the fully condensed multicomponent working fluid passes from the evaporation / condensation subsystem 24 through the heat exchanger 27 in line 26 and through the preheater 14. As indicated by line 28, heat is supplied from the exhaust gas of the gas turbine to boiler 12, although it will be appreciated that this heat may be increased as much as is available from other systems. The preheated working fluid branches to the first stream via line 30 passing through the generator preheater 21 to recover heat from the exhaust gas of the medium pressure turbine IP. The working fluid is combined with a second stream of working fluid from boiler 12 through line 33 and heat exchanged through heat exchanger 23 to return to the outlet of evaporator 16. As will be described below, the stream 29 exiting the heat exchanger 23 is heated by heat exchange with the hot gas in the gas cooling section 50 to return to the evaporator outlet. Heat exchange may be accomplished by placing the heat exchanger 23 directly in the gas cooler 50 or indirectly through an intermediate working fluid, if economical or desirable. The returned stream 29 and the stream in the boiler 12 are recombined in the boiler 12. The recombined stream of working fluid passes through the superheater 20, where the recombined stream is heat exchanged with the gas turbine exhaust stream 28 to flow to the inlet of the high pressure (HP) steam turbine. Finally overheated, the recombined stream in the high pressure steam turbine is expanded and converted from thermal energy to mechanical energy to drive the turbine. The expanded working fluid stream from the high pressure (HP) turbine is returned to boiler 12 via line 36 and reheated by reheater 18 in heat exchange with gas turbine exhaust via line 28. . The reheated working fluid flows through line 40 to the inlet of the medium pressure (IP) turbine. The working fluid expanded through the medium pressure (IP) turbine is passed through the line 34 to the heat generating preheater 21 in a heat exchange relationship, the working fluid stream passing through the line 30 from the preheater of the boiler 12. It is supplied to the preheater 21. Thus, the working fluid vapor from the medium pressure turbine is cooled and provides some of the heat required for vaporizing the working fluid in line 30. The working fluid from the preheater 21 travels through the line 42 to the inlet of the low pressure (LP) turbine, where it is expanded to the final fluid pressure level. Fluid expanded from the low pressure (LP) turbine passes through line 44 to the evaporation / condensation subsystem 24, where the fluid stream is condensed, pumped to a higher pressure, and via line 26 a boiler ( 12) cycle is continued.

Further, referring to FIG. 1, the vaporization system 46, which is generally schematically illustrated and sometimes considered a vaporizer, is a cooling section 50 having a gasifier section 48, a hot and cold cooling section 50a, 50b, respectively. And a gas cleanup unit 52. The carburetor receives feed additives and fuel such as coal or heavy oil through respective lines 49 and 51. The partially oxidized fuel gas leaves the carburettor 48 at a substantial high temperature and is cooled in the cooling section 50. After the fuel gas is cooled, the contaminants are removed from the gas cleanup unit 52. For example, the gas cleanup unit may include a low temperature device such as dry filtration that removes coagulated products by absorbing hydrogen sulfide using a water jet washer or a solvent. After the gas is cleaned up, the fuel gas is fed from the gas cleanup unit 52 through the line 56 to the combustor 54 of the gas.

Optionally provided air separation device 58 has injection air lines 60, 62, 64 for feeding nitrogen and oxidants to the vaporizer. Line 66 from air separation unit 58 supplies nitrogen to the gas turbine for low NO _X operation, while air from compressor discharge is directed to air separation unit via line 68. Supplied.

The Kalina cycle evaporation / condensation subsystem is used to absorb, condense, and regenerate working fluids and release them in low pressure (LP) steam turbines. The evaporation / condensation subsystem has a minimum of two pressure stages (eg, the high and low pressure sections shown) in which the working fluid mixture consisting of the composition passes through the two completely. More effective evaporation / condensation subsystems have three pressure stages (eg high pressure, medium pressure, low pressure sections) and mixing components that cause complete condensation. The mixed stream is assigned to a particular pressure section by determining the final condenser that sets the pressure of the stream (e.g., the low pressure condenser sets the pressure of the steam turbine exhaust line, thus allowing the turbine exhaust line to evaporate / condensate subsystems). It is considered to be in the low pressure part of). The present invention can be applied to any evaporation / condensation system with two or more pressure stage condensers.

From the foregoing, the heat energy stream from the vaporizer heats the working fluid in a kalina botoming cycle at a suitable location within the fluid system, replenishing heat energy from the gas turbine exhaust, maximizing the overall benefit of the heat stream, and consequently As a result, net generator power production and thermal efficiency will be improved. In particular, the heat energy from the high temperature cooling section 50a of the vaporizer is used in the heat exchanger 23 and optionally the heat exchangers 65 and 165 to increase the heat supplied to the multicomponent working fluid by the gas turbine exhaust gas. Let's do it. In addition, useful heat from the low temperature cooling section 50b of the vaporizer 48 is used in the heat exchanger 27 to heat the condensed multi-component working fluid. It should be noted that the feed temperature introduced into the HRVG, ie the preheater 14 or economizer section, is maintained above the dew point of the acidic gas by the heat exchanger 27.

It will be appreciated that fuel heating for the gas turbine or additional steam production may be accomplished by heat exchanger 63 using an extract from medium pressure (IP) turbine exhaust gas from line 34. The temperature of the multi-component stream exiting the heat exchanger 63 is adjusted to be approximately equal to the temperature of the stream exiting the power generation preheater 21. The stream exiting heat exchanger 63 is recombined in line 42 prior to entering the low pressure (LP) steam turbine. The heat source of the heat exchanger 63 may be an extract of useful heat from the vaporizer, for example the cold section 50b.

In addition, if additional heat is available in the vaporizer system, the additional heat exchanger 65 may be located via line 67, for example in parallel with HRVG having preheater and evaporator sections 14, 16, respectively. And the heat supplied is heat from the vaporizer as indicated by line 69. Further reheating may be performed as an option in heat exchanger 165 by heat exchange with hot vaporized gas in the gas cooling unit. The generator preheater 21 may be omitted based on generator economics, and reheating for injecting medium pressure (IP) exhaust gas into the low pressure (LP) steam turbine may be performed by using useful high temperature heating in the vaporizer. In addition, low grade heat useful in vaporizers and optional air separators can be used to regenerate working fluid in the evaporation / condensation subsystem. This low degree of integration in the evaporation / condensation subsystem improves system performance by reducing turbine back pressure, and reduces costs by generating reduction and higher temperature driving force.

Although the present invention has been described in terms of what is currently recognized as the most preferred embodiment, the invention is not limited to the above-described embodiments, but rather is intended to include various modifications and equivalent arrangements included within the spirit and scope of the appended claims. It will be understood.

Claims (13)

An integrated gasification complex having a plurality of turbines, including first and second steam turbines for driving one or more generators generating power or mechanical work and a gas turbine, and a fuel vaporizer for producing fuel gas for the gas turbine. In a method of operating a cycle power generation system, (a) producing fuel gas from the fuel vaporizer; (b) supplying a heat recovery fluid from the fuel vaporizer; (c) supplying the fuel gas from the fuel vaporizer to the combustor for the gas turbine to drive the gas turbine; (d) expanding a working fluid through the first steam turbine; (e) reheating the expanded working fluid from the first steam turbine; (f) expanding the reheated working fluid through the second steam turbine; (g) condensing the working fluid discharged from the second steam turbine; (h) passing the condensed working fluid in a heat exchange relationship with a hot exhaust gas from a gas turbine to flow a heated working fluid to the first and second steam turbines; (i) additionally heating the working fluid supplied to the first and second steam turbines by passing the working fluid in a heat exchange relationship with a heat recovery fluid. How the system works. The method of claim 1, The condensed working fluid is heated in a heat recovery steam generator in heat exchange relationship with the exhaust gas from the gas turbine, and the exhausted working fluid is in heat exchange relationship with a portion of the condensed working fluid passing through the heat recovery steam generator. (J) cooling the working fluid discharged from the second steam turbine by passing it therethrough. How the system works. The method of claim 1, (K) heating the condensed working fluid to form a partially condensed stream by passing the condensed working fluid in a heat exchange relationship with at least a portion of the cooled working fluid discharged from the second steam turbine. Containing How the system works. The method of claim 1, Said step (h) further comprising passing said condensed working fluid in a heat exchange relationship with said hot exhaust gas from said gas turbine in a superheater, The step (i) is carried out before the condensed working fluid passes through the superheater. How the system works The method of claim 1, Passing the condensed working fluid in a heat exchange relationship with a second heat recovery fluid and preheating the condensed working fluid by passing the condensed working fluid in a heat exchange relationship with a second heat recovery fluid. How the system works. The method of claim 1, Said step (g) is carried out by an evaporation / condensation subsystem, and said compressed working fluid is discharged from said second steam turbine to form a partially condensed stream prior to said step (h). Heating the compressed working fluid by passing it in a heat exchange relationship with at least a portion and passing the partially condensed stream through an evaporation / condensation subsystem. How the system works. Integral gasification comprising a plurality of gas turbines including first and second steam turbines and gas turbines for driving one or more generators for generating power or mechanical work, and a fuel vaporizer for producing fuel gas for the gas turbine. In a method for operating a combined cycle power generation system, (a) generating fuel from the fuel vaporizer; (b) supplying a heat recovery fluid from the fuel vaporizer; (c) supplying the fuel gas from the fuel vaporizer to the combustor for the gas turbine to drive the gas turbine; (d) expanding a working fluid through the first steam turbine; (e) reheating the expanded working fluid from the first steam turbine; (f) expanding the reheated working fluid through the second steam turbine; (g) condensing the working fluid discharged from the second steam turbine; (h) passing the condensed working fluid in a heat exchange relationship with a hot exhaust gas from a gas turbine to flow a heated working fluid to the first and second steam turbines; (i) heating the used working fluid discharged from one of the first and second steam turbines by passing the used working fluid in heat exchange relationship with the heat recovery fluid. How the system works. The method of claim 7, wherein The first steam turbine comprises a high pressure steam turbine, and further comprising passing the expanded working fluid through the high pressure turbine in heat exchange relationship with a heat recovery fluid. How the system works. The method of claim 7, wherein Said step (i) is carried out by passing said expanded working fluid through said second turbine in a heat exchange relationship with a heat recovery fluid. How the system works. (i) a plurality of turbines comprising a first steam turbine and a gas turbine operatively coupled with one or more generators to generate power or mechanical work; (ii) an evaporation / condensation subsystem; and (iii) a gas. A method of operating an integrated gasification combined cycle power generation system having a fuel vaporizer for producing fuel gas for a turbine, the method comprising: (a) producing fuel gas from the fuel vaporizer; (b) supplying a heat recovery fluid from the fuel vaporizer; (c) supplying the fuel gas from the fuel vaporizer to the combustor for the gas turbine to drive the gas turbine; (d) expanding a working fluid consisting of a mixture of different components having different boiling points at the same pressure through the first steam turbine and producing a used stream of the mixture of different components, (e) condensing said used stream in said subsystem, (f) passing the condensed working fluid in a heat exchange relationship with the hot exhaust gas from the steam turbine to flow a heated working fluid to the gas turbine; (g) heating the working fluid by passing the working fluid in a heat exchange relationship with the heat recovery fluid. How the system works. The method of claim 10, And a second steam turbine, wherein the condensed working fluid is heated in a heat recovery steam generator in heat exchange relationship with the exhaust gas from the gas turbine, Cooling the working fluid discharged from the second steam turbine by passing the exhausted working fluid in a heat exchange relationship with a portion of the condensed working fluid passing through the heat recovery steam generator. How the system works. The method of claim 10, The step (f) is performed in part by passing the condensed working fluid in a heat exchange relationship with the hot gas of the gas turbine in the superheater, wherein step (g) is performed before the condensed working fluid passes through the superheater. Performed How the system works. The method of claim 10, The first steam turbine including the high pressure steam turbine, and passing the working fluid expanded through the high pressure turbine through the high pressure turbine in heat exchange relationship with the heat recovery fluid; How the system works.

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