JP2000337108A - Carbon dioxide recovery type combined generating system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of NOX and to improve power generating efficiency. SOLUTION: Working fluid from a compressor 1 and CH1 and O2 are supplied to a combustor 2 and burnt to produce working fluid wherein high temperature H2O and CO2 produce a product. A turbine 3 is rotated to generate a power. Fluid after expansion is brought into condensate by a condenser 10, and is returned through a line 15 to the compressor 1. Surplus CO2 is removed from the condenser 10 by a CO2 discharge compressor 11. Further, steatn heated by an exhaust gas boiler 4 flows in a steam turbine 5 and is brought into condensate by a condenser 6 after a work and the condensate is returned to a boiler 4 by a pump 7. A gas turbine is caused to form a closed loop by a line 15 and since the compressor 1 does not suck air, no NOX is generated. Further, since the CO2 discharge compressor 11 is used, discharge of CO2 is facilitated, a compression ratio is increased to a high value, and an output is increased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a carbon dioxide capture hybrid power system BACKGROUND OF THE INVENTION The compressor, a gas turbine, a system of the exhaust gas boiler and configured to operate the steam turbine system with the exhaust gas boiler while closed of, NO _X
And a system configuration that increases the output.

[0002]

2. Description of the Related Art PSA (Pressure Swing Absorption) method and membrane separation method have been proposed as methods for separating carbon dioxide generated in a power plant from fuel exhaust gas in order to cope with the problem of global warming. At present, such a carbon dioxide separation device is not applied to a gas turbine combined plant, which is a high-efficiency power generation plant. However, the net power generation efficiency taking into account the power is significantly reduced.

FIG. 5 shows an example in which a conventional gas turbine combined plant is equipped with a CO ₂ separation device. In the figure, 1 is a compressor constituting a gas turbine, 2 is a combustor for burning hydrocarbon fuel such as CH ₄ , and 3 is a turbine. An exhaust gas boiler 4 guides exhaust gas from the turbine 3 and recovers exhaust heat. 5 is a steam turbine, 6 is a condenser (condenser), 7 is a pump, which constitutes a closed loop and generates steam by the exhaust heat of the turbine 3 by the exhaust heat recovery boiler 4,
The expanded steam that has driven and operated the steam turbine 5 is condensed by the condenser 6, and is again returned to the exhaust heat recovery boiler 4 by the pump 7.
To form a steam turbine system. Reference numeral 8 denotes a generator, which is driven by the turbine 3 to obtain electric power. 30 is C
The O ₂ separation device separates and recovers CO ₂ from exhaust gas from the exhaust gas boiler 4 by the above-described PSA method, membrane separation method, or the like.

In the plant having the above configuration, the compressor 1 sucks air from the atmosphere, compresses the air, and supplies the compressed air to the combustor 2.
In the combustor 2, the air from the compressor 1 and a hydrocarbon fuel,
For example, methane (CH ₄ ) is supplied and combusted to produce high-temperature combustion gas, which flows into the turbine 3 and expands, thereby expanding the turbine 3.
Is rotated to perform work, and the exhaust gas is guided to the exhaust heat recovery boiler 4, where the exhaust heat is given and the exhaust gas is discharged. The discharged exhaust gas contains CO ₂ by combustion, and this CO ₂
The gas is separated and collected by the O ₂ separation device 30 and released from the chimney 40 to the atmosphere.

On the other hand, in the exhaust gas boiler 4, steam is generated in a lower closed loop by the exhaust heat, and the steam is supplied to the steam turbine 5, and expands to rotate the steam turbine 5 to perform work, and the temperature becomes low. The steam is condensed into water by the condenser 6 and is sent again to the exhaust gas boiler 4 by the pump 7.

[0006] In the system shown in Figure 5 above, the carbon dioxide in the exhaust gas is slight, and its split CO ₂
Separation device 30 has a large capacity, is a complicated and expensive device, and has a large power, which significantly lowers the net power generation efficiency. The compressor 1 draws in air, compresses the air, supplies the compressed air to the combustor 2, and is used for fuel combustion. However, since the air contains a nitrogen component and the exhaust gas is discharged from the chimney 40 to the atmosphere, NO _This is the cause of the occurrence of _X.

FIG. 6 shows another example of a conventional gas turbine plant. Reference numerals 1 to 4 and 8 have the same structure as in FIG. In the figure, after exhaust heat of a turbine 3 is recovered by an exhaust gas boiler 4, the exhaust water is condensed by a condenser 20, and a part of the condensed water is sent to the exhaust gas boiler 4 by a pump 21, It is heated and injected into the combustor 2. The remaining condensate is discharged from the line 41 to the outside, also, the exhaust gas from the condenser 20 is CO ₂ in the CO ₂ separation device 30 separates and is released is recovered from the chimney 40 into the atmosphere. In such a system, a configuration of a so-called steam injection cycle in which steam is generated by the exhaust gas boiler 4 and the steam is injected into the combustor 2 to obtain a large output increase is shown. The power generation efficiency of the separation power is large net carbon dioxide of the exhaust gas as in the case of a gas turbine combined even in this system is shown in FIG. 5 is reduced, also, the compressor 1 is generated similarly NO _X so draws air from the atmosphere Is the cause.

[0008]

As described above, in the conventional gas turbine plant, the CO ₂ separation device 30 is used.
Is a large-capacity, expensive device, and requires a large amount of power, resulting in a significant decrease in net power generation efficiency. or,
In the compressor 1, air is sucked in from the atmosphere and supplied to the combustor 2 for combustion, and the exhaust gas is discharged to the atmosphere, so that NO _X is generated.

[0009] The present invention provides a carbon dioxide capture combined cycle power plant, there is ensured an increase in the output by increasing the pressure ratio, using a relatively discharge compressor for carbon dioxide separation concise structure and NO _X It is an object of the present invention to realize a configuration of a power generation plant that does not cause any problem.

[0010]

The present invention provides the following means (1) to (5) in order to solve the above-mentioned problems.

(1) A compressor for compressing a working fluid composed of carbon dioxide and water vapor, a combustor for burning fuel together with the working fluid from the compressor to generate a high-temperature working fluid,
A turbine that obtains electric power by expanding a high-temperature working fluid from the combustor, a heat exchanger that heats steam of a steam turbine system by exhaust heat of the working fluid discharged from the turbine, and flows out of the heat exchanger. A condenser for condensing the low-temperature working fluid, a return line for returning the working fluid from the condenser to the compressor,
A combined carbon dioxide recovery power generation system comprising a discharge compressor for discharging carbon dioxide from the return line.

(2) In the above invention (1), when both the turbine and the steam turbine system operate, the heat exchanger operates as an exhaust heat recovery boiler, and the steam turbine system operates alone. A system that operates as a steam generating boiler if it does.

(3) In the invention of the above (1) or (2), a regenerative heat exchanger is provided in a flow path for guiding the working fluid from the turbine to the heat exchanger, and the regenerative heat exchanger is provided with a compressor. A system wherein a working fluid compressed by a machine is heated by exhaust heat of the turbine and supplied to the combustor.

(4) In any one of the above inventions (1) to (3), the compressor is constituted by connecting a low-pressure compressor and a high-pressure compressor, and an intercooler is provided between the two compressors. A system for supplying a part of the working fluid condensed by the condenser to the intercooler to reduce the temperature of the working fluid at the outlet of the low-pressure compressor.

(5) A compressor for compressing a working fluid composed of carbon dioxide and water vapor, a combustor for burning fuel together with the working fluid from the compressor to generate a high-temperature working fluid,
A turbine that expands the high-temperature working fluid from the combustor to obtain electric power, a heat exchanger that collects exhaust heat of the working fluid discharged from the turbine, and a steam heated by the heat exchanger for expansion. A steam turbine that obtains electric power from the steam turbine, a condenser that condenses exhaust gas from the steam turbine, a pump that returns condensate from the condenser to the heat exchanger, and a turbine that flows out of the heat exchanger. A condenser for condensing exhaust gas, a return line for returning working fluid from the condenser to the compressor, and a discharge compressor for discharging carbon dioxide from the return line. Combined power generation system with carbon dioxide capture.

In (1) and (5) of the present invention, the working fluid combusted in the combustor is composed of carbon dioxide and water vapor, and the compressor, turbine, heat exchanger, and condenser form a closed loop by the return line. are doing. The high-temperature working fluid generated by combustion in the combustor expands in the turbine and rotates the turbine to generate electricity.The working fluid that has worked enters the heat exchanger and gives waste heat to the steam turbine system, and the condenser And the water is returned to the compressor by the return line. From the return line, CO _2, a combustion product contained in the working fluid, is compressed to atmospheric pressure by a discharge compressor and discharged. Accordingly, the compressor does not draw in air, and is made up of only CO ₂ and H ₂ O in a closed loop, so that NO _X is not generated. Further, H ₂ O and CO ₂ can be easily separated using a discharge compressor having a simple structure, and the output can be improved by increasing the pressure ratio.

In (2) of the present invention, since the heat exchanger has both functions of an exhaust heat recovery boiler and a steam generator-only boiler, both cycles of the gas turbine system and the steam turbine system operate. When the steam turbine system is operating independently, it functions as a waste heat boiler that gives steam from the turbine to the steam turbine system to heat the steam.
It functions as a boiler for a steam turbine that generates steam. Therefore, the operational range of the invention (1) is expanded, and the function is improved.

In (3) of the present invention, the working fluid compressed by the compressor is heated by the exhaust heat of the turbine in the regenerative heat exchanger to increase the temperature, and is supplied to the combustor. The fuel amount can be reduced and the thermal efficiency can be increased as compared with the invention of (2).

In (4) of the present invention, the compressor has two stages of low pressure and high pressure, an intercooler is provided between the two compressors, and a condenser is provided at the outlet of the low pressure compressor by a condenser. The watered working fluid is injected from the intercooler to lower the temperature at the outlet of the low-pressure compressor. Accordingly, since the inlet temperature of the high-pressure compressor is reduced, the power of the compressor is reduced, and the output of the turbine is further increased as compared with the above inventions (1) to (3).

[0020]

Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a system diagram of a carbon dioxide capture integrated power generation system according to a first embodiment of the present invention. In the figure, reference numerals 1 to 8 have the same configuration as that of the conventional combined cycle power plant shown in FIG. This is described in detail below.

In FIG. 1, reference numeral 10 denotes a condenser;
Is a carbon dioxide (CO ₂ ) discharge compressor, 15 is a condenser 10
This is a return line connecting the outlet side of the compressor and the inlet side of the compressor 1. In the first embodiment of the present invention, the return line 15 connects the exhaust gas side outlet of the exhaust gas boiler 4 and the compressor 1 inlet,
Further, a CO ₂ discharge compressor 11 is provided at the outlet of the condenser 10. That is, the gas turbine combined cycle system is a closed loop.

In the system having the above-described configuration, the compressed working fluid from the compressor 1 flows into the combustor 2, and CH _{4 of} the fuel is injected together with an equivalent amount of oxygen. As a result, the working fluid becomes only carbon dioxide (CO ₂ ) and water vapor (H ₂ O) when the fuel is natural gas mainly composed of methane (CH ₄ ), and carbon dioxide and water as fuel products flow into the turbine 3. ,
By expansion, the turbine 3 is rotated to generate electric power by the generator 8, and the working fluid that has completed its work is discharged from the exhaust gas boiler 4.
Gives waste heat to the closed loop of the steam turbine system by the condenser 10
It is led by water to return. The working fluid from the condenser 10 is returned to the compressor 1 via the return line 15. In addition, condenser 10
Of the working fluid that has exited, the excess CO ₂ is compressed to atmospheric pressure by the CO ₂ discharge compressor 11 and discharged outside.

On the other hand, the steam turbine system connected to the exhaust gas boiler 4 forms a closed loop, and the steam heated by the exhaust heat of the exhaust gas boiler 4 is supplied to the steam turbine 5,
By expansion, the steam turbine 5 is rotated to obtain electric power, and the low-temperature steam that has completed its work is led to the condenser 6 to be condensed, and is again led to the exhaust gas boiler 4 by the pump 7 to be heated. Turns into steam.

In the first embodiment described above, the compressor 1, the turbine 3, the exhaust gas boiler 4, and the condenser 10 constitute a closed loop, and the exhaust heat recovery boiler 4 has a closed loop of a steam turbine system. Since the compressor 1 is connected and the compressor 1 does not use air, NO _X is not generated. Also, CO ₂
The discharge compressor 11 is constituted by a multi-stage compressor. The inlet side of the CO ₂ discharge compressor 11 is lower than the atmospheric pressure, and the output is increased correspondingly because the pressure ratio of the plant is large. Furthermore, the CO ₂ discharge compressor 11 has a simpler structure than conventional PSA and membrane separation methods, and the cost of the apparatus can be kept low. Further, a combustion products CO ₂ and H ₂ O are readily separated from the system, the discharge of the CO ₂ is CO ₂ emission compressor 1
1 facilitates this.

FIG. 2 is a system diagram of a combined power generation system of a carbon dioxide capture type according to a second embodiment of the present invention. In the figure, a characteristic portion of the second embodiment is a portion denoted by reference numeral 50, and has a configuration in which a boiler 50 is provided instead of the exhaust gas boiler shown in FIG. The other configuration is the same as that of the first embodiment shown in FIG.

In the figure, reference numeral 50 denotes a boiler, which comprises an exhaust gas boiler 50a and a boiler 50b for generating steam. The exhaust gas boiler 50a corresponds to the exhaust gas boiler 4 shown in FIG. 1 and guides exhaust gas from the turbine 3 and gives the exhaust heat to the steam turbine system. The boiler 50b stops the system of the upper turbine 3 and operates when only the lower steam turbine system is operated alone. Only in this case, the steam of the steam turbine system is heated and supplied to the steam turbine 5, The steam turbine system can be operated independently. In the second embodiment of this embodiment, as in the first embodiment of FIG. 1, without the occurrence of NO _X, it is possible to enhance the power generation efficiency.

FIG. 3 is a system diagram of a combined power generation system with carbon dioxide capture according to a third embodiment of the present invention. The features of the third embodiment are indicated by reference numeral 12, and the other configuration is the same as that of the first embodiment shown in FIG. 1, and the description of these portions will be omitted.

In the figure, reference numeral 12 denotes a regenerative heat exchanger. The outlet gas of the compressor 1 flows into the regenerative heat exchanger 12 and exchanges heat with the outlet gas of the turbine 3. The fuel is increased and supplied to the combustor 2 to reduce the fuel amount of the combustor 2 and increase the thermal efficiency. In such a third embodiment, NO as in the first embodiment shown in FIG.
_X is not generated, and the effect of increasing the power generation efficiency further than in the first embodiment is achieved.

FIG. 4 is a system diagram of a carbon dioxide recovery combined cycle power generation system according to a fourth embodiment of the present invention. The features of the fourth embodiment are that the compressor is a low-pressure compressor 1a and a high-pressure compressor. 1b, and an intercooler 13 is provided between the two compressors 1a and 1b.
Since the pump is supplied by the pump 14, and other configurations are the same as those of the first embodiment shown in FIG. 1, the description of these portions will be omitted.

In FIG. 4, the working fluid supplied to the combustor 2 is compressed by the low-pressure compressor 1a and the high-pressure compressor 1b, and burns in the combustor 2 with the equivalent of CH ₄ of fuel and O ₂ , The turbine 3 is driven. The working fluid that has worked in the turbine 3 flows into the exhaust gas boiler 4, gives exhaust heat to the steam turbine system, and condenses water in the condenser 10.
Returning to a, through the return line 15, CO _{2 as} a combustion product is discharged to the outside by the CO ₂ discharge compressor 11 in the same manner as in FIG.

A part of the water condensed in the condenser 10 is supplied to the pump 1
4 cools the working fluid that is guided to the intercooler 13 and is supplied between the low-pressure compressor 1a and the high-pressure compressor 1b and flows into the high-pressure compressor 1b. This reduces the power of the compressor and increases the output of the power plant.

According to the fourth embodiment described above, FIG.
NO as in the first embodiment shown in FIG._XWithout the occurrence of
Further, it is possible to further increase the output than in the first embodiment.
it can. Also, as in FIG._TwoBy discharge compressor 11
Excess CO, a product of combustion _TwoCan also be easily discharged
Can be.

[0033]

The combined power generation system of the present invention has the following features. (1) A compressor for compressing a working fluid composed of carbon dioxide and water vapor, and a high-temperature operation by burning fuel together with the working fluid from the compressor. A combustor that generates fluid, a turbine that expands a high-temperature working fluid from the combustor to obtain electric power, and a heat exchanger that heats steam of a steam turbine system by exhaust heat of the working fluid discharged from the turbine. A condenser for condensing low-temperature working fluid flowing out of the heat exchanger, a return line for returning working fluid from the condenser to the compressor, and a discharge compressor for discharging carbon dioxide from the return line. It is characterized by comprising. Such a system, the compressor without sucking air, never NO _X occurs since only CO ₂ and H ₂ O by a closed loop. Further, H ₂ O and CO ₂ can be easily separated using a discharge compressor having a simple structure, and the output can be improved by increasing the pressure ratio.

In (2) of the present invention, since the heat exchanger has both functions of an exhaust heat recovery boiler and a steam generator-only boiler, both cycles of the gas turbine system and the steam turbine system operate. When the steam turbine system is operating independently, it functions as a waste heat boiler that gives steam from the turbine to the steam turbine system to heat the steam.
It functions as a boiler for a steam turbine that generates steam. Therefore, the operational range of the invention (1) is expanded, and the function is improved.

In the method (3) of the present invention, the working fluid compressed by the compressor is heated by the exhaust heat of the turbine in the regenerative heat exchanger to increase the temperature and is supplied to the combustor. The fuel amount can be reduced and the thermal efficiency can be increased as compared with the invention of (2).

In (4) of the present invention, the compressor has two stages of low pressure and high pressure, an intercooler is provided between both compressors, and a condenser is provided at the outlet of the low pressure compressor by a condenser. The watered working fluid is injected from the intercooler to lower the temperature at the outlet of the low-pressure compressor. Accordingly, since the inlet temperature of the high-pressure compressor is reduced, the power of the compressor is reduced, and the output of the turbine is further increased as compared with the above inventions (1) to (3).

In (5) of the present invention, the steam turbine system has a steam turbine, a steam turbine system condenser, and a pump, and forms a loop heated by the exhaust gas of the heat exchanger. And the same effect as the invention of the above (1) can be obtained.

[Brief description of the drawings]

FIG. 1 is a system diagram of a carbon dioxide capture integrated power generation system according to a first embodiment of the present invention.

FIG. 2 is a system diagram of a carbon dioxide capture integrated power generation system according to a second embodiment of the present invention.

FIG. 3 is a system diagram of a carbon dioxide capture integrated power generation system according to a third embodiment of the present invention.

FIG. 4 is a system diagram of a carbon dioxide capture integrated power generation system according to a fourth embodiment of the present invention.

FIG. 5 is a system diagram of a conventional gas turbine combined plant.

FIG. 6 is a system diagram of a conventional gas turbine plant that injects steam into a combustor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 2 Combustor 3 Turbine 4 Exhaust gas boiler 5 Steam turbine 6,10 Condenser 7,14 Pump 8 Generator 11 Carbon dioxide discharge compressor 12 Regeneration heat exchanger 13 Intercooler 15 Line 50 Steam generator

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Kazuo Agematsu 2-1-1, Shinhama, Arai-machi, Takasago City, Hyogo Prefecture Inside the Takasago Works, Mitsubishi Heavy Industries, Ltd. (72) Tadashi Tadashi 2-1-1, Niihama, Arai-machi, Takasago City, Hyogo Prefecture No. 1 F-term in Takasago Works, Mitsubishi Heavy Industries, Ltd. (reference) 3G081 BA02 BA11 BB00 BC07 BD00 DA22

Claims (5)

[Claims] 1. A compressor for compressing a working fluid composed of carbon dioxide and water vapor, a combustor for burning fuel together with the working fluid from the compressor to generate a high-temperature working fluid, and a high-temperature operation from the combustor. A turbine that obtains electric power by expanding the fluid, a heat exchanger that heats steam of a steam turbine system by exhaust heat of the working fluid discharged from the turbine, and condenses low-temperature working fluid flowing out of the heat exchanger A condenser, a return line for returning a working fluid from the condenser to the compressor, and a discharge compressor for discharging carbon dioxide from the return line. Power generation system. 2. The heat exchanger operates as an exhaust heat recovery boiler when both the turbine and the steam turbine system operate, and as a steam generating boiler when the steam turbine system operates alone. The combined power generation system according to claim 1, which operates. 3. A regenerative heat exchanger is provided in a flow path for guiding the working fluid from the turbine to the heat exchanger, and the regenerative heat exchanger converts the working fluid compressed by the compressor by exhaust heat of the turbine. The combined power generation system according to claim 1, wherein the combined power generation system is heated and supplied to the combustor. 4. The compressor is configured by connecting a low-pressure compressor and a high-pressure compressor, an intercooler is provided between the two compressors, and the intercooler is condensed by the condenser. The combined power generation system according to any one of claims 1 to 3, wherein a part of the working fluid is supplied to lower the temperature of the working fluid at the outlet of the low-pressure compressor. 5. A compressor for compressing a working fluid composed of carbon dioxide and water vapor, a combustor for burning fuel together with the working fluid from the compressor to generate a high-temperature working fluid, and a high-temperature operation from the combustor. A turbine that obtains electric power by expanding a fluid, a heat exchanger that recovers exhaust heat of a working fluid discharged from the turbine, and a steam turbine that obtains electric power by introducing and expanding steam heated by the heat exchanger. A condenser for condensing exhaust of the steam turbine, a pump for returning condensate from the condenser to the heat exchanger, and a condensate for condensing exhaust of the turbine flowing out of the heat exchanger , A return line for returning the working fluid from the condenser to the compressor, and a discharge compressor for discharging carbon dioxide from the return line; .