JP2001216992A - Complex generation plant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a complex generation plant for generating power with fuel cells (FC generation parts), a gas turbine and a steam turbine, while saving the consumption of a fuel and improving plant efficiency. SOLUTION: Plurality of FC generation parts 21, 22 are installed in series and an exhaust gas from the front-stage generation part is supplied to the rear-stage generation part for generating power. One compressor 460 is required for supplying an air to the plural-stage FC generation parts, resulting in relatively small compressing power to be required. That is, compressing power per generation output can be reduced and a high-temperature air/fuel gas can be supplied to the next-stage FC generation part. As a result, the generation output of the FC generation parts is improved and, in addition, the consumption of a fuel in a combustor for additional combustion to maintain the operating temperature of a gas turbine can be saved because of a high-temperature exhaust gas to be supplied from the final-stage FC generation part to the combustor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combined power plant that generates power by combining a fuel cell, a gas turbine, and a steam turbine.

[0002]

2. Description of the Related Art A fuel cell (FC) has a high power generation efficiency of about 80% of the thermal energy held by the fuel gas theoretically from the supplied fuel gas and air, and the electric energy (actually, about 60%). %) As well as heat energy that can be recovered and used from the battery body and exhaust gas. Therefore, if these heat energies are recovered by a topping cycle of a gas turbine (GT) or a bottoming cycle of a steam turbine (ST) and used for power generation, heat discharged from the system (= system loss) can be reduced. As a result, high power generation efficiency can be obtained. For this reason, a combined cycle power plant combining a FC power generation unit provided with a fuel cell, a gas turbine, and a steam turbine is expected to have a high energy saving effect.

Further, the FC of such a combined cycle power plant
Fuel cells used in the power generation section include solid oxide fuel cells (SOFC), molten carbonate fuel cells (MCFC), and phosphoric acid fuel cells (PAFC). A gas that can be supplied as a working gas is used. Further, a fuel cell generates an electrochemical reaction in a reaction gas, that is, a fuel cell, and the higher the supply pressure of the fuel gas and air for generating electric power, the higher the power generation efficiency is obtained. Pressurized FC power generation unit which operates by pressurizing is used.

[0004] In particular, oxygen required for the reaction of the air electrode provided in the FC power generation unit is supplied by taking in air from the atmosphere, so it is necessary to increase the oxygen partial pressure. This is possible by increasing the pressure by an air compressor and supplying it to the air electrode of the FC power generation unit. As a driving power source of the air compressor, a gas turbine that burns fuel in exhaust gas from the FC power generation unit and drives the high-temperature exhaust gas as a working fluid is equipped, and the air compressor is attached to the gas turbine. A method of driving by coaxial connection or a method of driving a generator by this gas turbine to generate electric power and driving an air compressor by an electric motor driven by the electric power are conceivable.

FIG. 10 shows an internal reforming SOFC using natural gas (hereinafter referred to as fuel gas) as fuel and air.
In addition to using the heat of the high-temperature exhaust gas discharged from the FC power generation unit provided with the SOFC in the GT power generation unit,
It is a schematic structure figure showing an example of a combined cycle power plant in which heat of exhaust gas discharged from a power generation unit is collected by a GT exhaust heat recovery unit.

As shown in FIG.
000 are mainly a fuel gas supply unit 600, an air supply unit 700, an FC power generation unit 100, and a GT power generation unit 400.
And a GT exhaust heat recovery unit 500. Among them, the FC power generation unit 100 is provided with a fuel gas 300 of a predetermined temperature.
And an air 300 having an air ratio of 5 to 7 at approximately the same temperature is introduced into a fuel electrode and an air electrode composed of a fixed electrolyte disposed therein to cause an electrochemical reaction to generate electric power.
The power generation unit 400 compresses air taken in from the atmosphere to generate F
The gas is supplied to the C power generation unit 100 and generates power, and the GT exhaust heat recovery unit 500 reforms the fuel gas, air preheating, and fuel gas supplied to the FC power generation unit 100 with the exhaust gas discharged from the GT power generation unit 400. In addition to generating reformed steam, drive steam for generating electric power by a steam turbine (not shown) is generated.

The FC power generation unit 100 and the GT power generation unit 40
0, the combustion section 200 and the reaction gas heating section 300
In the combustion section 200, unburned fuel gas and air supplied to the FC power generation section 100 are supplied to the FC power generation section 1.
By burning a gas G100 by reaction of 00, further generates a combustion gas G ₂₀₀ of high temperature (e.g. 1200 ° C. or higher), in the reaction gas heating unit 300, FC
Fuel gas F ₅₄₀ and air A ₅₂₀ supplied to the power generation unit 100
Is heated to the above-mentioned predetermined temperature.

That is, as shown in the figure, the reaction gas heating section 300 converts the fuel gas F ₅₂₀ heated to an intermediate temperature by a fuel preheating regenerator 520 described later into an FC power using the heat of the combustion gas G _200. The fuel gas heater 320 which heats to the final temperature which is the inlet temperature of the section 100, and the air A ₅₂₀ which is also heated to the intermediate temperature by the air preheating regenerator 540 utilizing the heat of the combustion gas G ₂₀₀ at 950 ° C. And an air heater 340 for heating up to.

On the other hand, the GT power generation section 400 includes a combustor 420
, A gas turbine (GT) 440 and an air compressor 460
And a generator 480. Combustor 420
Is connected to the fuel gas supply unit 600 and the reaction gas heating unit 300.
Is connected, and the fuel gas F
₅₄₀And air A₅₂₀Cooling by heating
For example, about 880 ° C.)₃₀₀Of fuel gas
Part F ₄₀₀To mix and reburn.
High temperature combustion gas G at a predetermined turbine inlet temperature₄₂₀West
The gas is supplied to the gas turbine 440.

The gas turbine 440 uses the combustion gas G
_The power is recovered by being driven with the ₄₂₀ as the working fluid, and the compressor 460 connected coaxially is driven. This compressor 46
0, the air A ₇₀₀ is sucked from the air supply unit 700, compressed and supplied to the FC power generation unit 100, and the air compressor 460 is coaxially connected to the power generator 480. 480 is activated to generate power.

The GT exhaust heat recovery system 500 includes the air preheating regenerator 520 and the fuel gas preheating regenerator 540 described above.
510, a steam generator 560, and a chimney 580. The exhaust gas G ₄₄₀ discharged from the gas turbine 440 of the GT power generation unit 400 is GT
Sent to the air preheater regenerator 520 provided in the preheating reproducing unit 510 of the exhaust heat recovery unit 500, the air preheater regenerator 520, 400 ° C. approximately for utilizing the heat of exhaust gas G ₄₄₀ discharged from the air compressor 460 the air a ₄₆₀ supplies the preheated to an intermediate temperature to the air heating unit 340.

Further, the fuel gas pre regenerator 540 is juxtaposed with the air preheater regenerator 520 for preheating the reproduction unit 510, the fuel gas supply unit 60 by utilizing the heat of the exhaust gas G ₄₄₀
The fuel gas F ₅₀₀ of about 15 ° C. supplied from 0 is preheated to an intermediate temperature and supplied to the fuel gas heating section 320. Exhaust gas G discharged from the fuel gas preheating regenerator 540
₅₄₀ is sent to the steam generator 560, where steam is generated, the generated steam, as well is mixed with the fuel gas F ₅₀₀ for internal reforming, is supplied to the outside of the steam turbine is not shown, the generator I'm trying to do it. Also,
Exhaust gas G ₅₆₀ (for example, about 100 ° C.) generated by the steam generator 560 is released into the atmosphere from a chimney 580.

Next, the operation of the above-mentioned conventional combined cycle power generation plant when the operating temperature of the SOFC is controlled to an optimum value for the electrochemical reaction will be described.

First, a fuel gas F ₆₀₀ composed of natural gas or the like at about 15 ° C. supplied from a fuel gas supply unit 600 is branched into two parts, one fuel gas F ₄₀₀ is introduced into a combustor 420 and the exhaust gas G ₃₀₀ is heated to operating temperatures of the gas turbine 440, the other of the fuel gas F ₅₀₀ is preheated to be introduced into the fuel gas pre-regenerator 540 to an intermediate temperature. Fuel gas F _{540 that} has passed through fuel gas preheating regenerator 540 is steam (internal reforming steam) supplied from steam generator 560.
After being mixed with _S560 and having a predetermined steam / fuel gas ratio, the mixture is introduced into the fuel gas heater 320, and the FC power generation unit 10
The fuel is heated to the optimum supply temperature introduced to zero and introduced to the fuel electrode side of the FC power generation unit 100.

On the other hand, the air A ₇₀₀ taken in from the air supply unit 700 is introduced into the air compressor 460 and compressed, and the temperature rises to about 400 ° C. during the compression process. The air A ₄₆₀ discharged from the air compressor ₄₆₀ is _supplied to the air preheating regenerator 5.
20 and preheated to an intermediate temperature. Further, the compressed air A ₅₂₀ preheated by the air preheat regenerator ₅₂₀ is introduced into the air heater 340, and similarly, the FC power generator 100
And is introduced to the air electrode side of the FC power generation unit 100.

In the FC power generation unit 100, a mixed gas F of fuel gas and steam introduced to the fuel electrode side is used.
_{The 300} reacts on the anode catalyst to produce hydrogen H ₂ and carbon monoxide CO. The hydrogen H ₂ , the carbon monoxide CO, and the oxygen O ₂ in the compressed air A ₄₀₀ on the air electrode side cause an electrochemical reaction via a solid oxide electrolyte arranged to partition the inside of the FC power generation unit 100. Produces water and carbon dioxide. Here, in the FC power generation unit 100, of the reaction heat (enthalpy change; ΔH), the free energy change (Δ
The amount obtained by subtracting the amount based on the internal resistance of the battery from the amount corresponding to G) is converted into electric energy (DC power), and the amount based on the internal resistance of the battery and the amount (−T · ΔS) based on the entropy change are obtained. It is mainly generated as heat. At this time, since the generation of water or carbon dioxide is an exothermic reaction, as the battery reaction proceeds, the FC power generation unit 1
The temperature of 00 rises.

The fuel electrode exhaust gas and the air electrode exhaust gas that have passed through the FC power generation unit 100 are mixed, and the exhaust gas G at about 1050 ° C.
₁₀₀ is introduced into the combustion unit 200. This combustion section 20
At 0, cause oxygen and combustion reaction of the fuel gas components in the air remaining unreacted in the exhaust gas G _100, further comprising a combustion gas G ₂₀₀ of high temperature. Hot combustion gases G ₂₀₀ that has passed through the combustion section 200 is branched into two hands reactive gas heating unit 300, mixing of each fuel gas pre regenerator 540 in preheated fuel gas F _{54 0} and reforming steam s ₅₆₀ Gas F ₅₄₀ and air A preheated by air preheat regenerator 520
₅₂₀ are heated to the optimal operating temperature of the SOFC by heat exchange.

Exhaust gas G that has passed through the reaction gas heating unit 300
₃₀₀ is introduced into a combustor 420 in the GT power generation unit 400. During this exhaust gas G _300, is present oxygen unburned, again burned by mixed with fuel gas F ₄₀₀ supplied from the fuel gas supply unit 600 to the combustor 420, as a high-temperature exhaust gas G ₄₂₀ It is supplied to the GT power generation unit 400. High temperature exhaust gas G discharged from combustor 420
₄₂₀ is introduced into the gas turbine 440 of the GT power generation unit 400 and drives the gas turbine 440. As a result, the gas turbine 440 becomes a driving power source, and the air compressor 460 and the generator 480 connected coaxially with the gas turbine 440 operate respectively, and the air A finally supplied to the FC power generation unit 100 is operated.
Generate ₄₆₀ and power.

Exhaust gas discharged from gas turbine 440
G₄₄₀Is the air preheating regenerator 520 and the fuel gas preheating regeneration
Air 540 as described above.₄₆₀And breaks
Quality steam₅₆₀Mixed with fuel gas F₅₀₀By heat exchange
Preheat. These preheaters 520 and 540 discharge
Exhaust gas G₅₄₀Is introduced into the steam generator 560,
The water supplied into the gas generator 560 is converted into steam. Ma
Some of the steam generated by the steam generator 560 is
As reformed steam s ₅₆₀Used as the remaining steam
Is supplied to a steam turbine (not shown)
And a generator directly connected to the steam turbine
And generate power. Further, from the steam generator 560
Exhaust gas G cooled down to about 100 ℃₅₆₀
Is released from the chimney 580 into the atmosphere.

As in the combined power plant 1000 described above, an SOFC operating at a relatively high temperature as a fuel cell,
In a combined cycle power plant using a PAFC or the like for the FC power generation unit in addition to the MCFC, since the electrochemical reaction of the fuel cell is an exothermic reaction, the temperature of the FC power generation unit 100 increases during operation, Deterioration or corrosion of cell constituent materials progresses, and the life of the fuel cell becomes extremely short;
In addition, there arises an inconsistency in that the electric resistance increases and the power generation output decreases. On the other hand, if the FC power generation unit 100 is excessively cooled,
A desired output cannot be obtained because the reaction rate of the electrode reaction of the fuel cell decreases and the ionic conductivity of the electrolyte decreases. Therefore, it is extremely important to maintain the operating FC power generation unit 100 at a desired operating temperature.

[0021]

In the above-mentioned conventional combined cycle power plant 1000, in order to cool the FC power generation unit 100 and maintain it at a desired operating temperature, an optimum operating temperature (about 950) is required.
The temperature of the FC power generation unit is cooled by supplying an excess amount of air heated to the temperature of (° C.) above the amount required for the battery reaction. However, if a large amount of air is to be supplied under pressure, an extremely large amount of driving power is required for the compressor 460 of the GT power generation unit 400, which is the air supply source. For example, in the case of the combined cycle power plant 1000, F
The pressurized air for cooling to be supplied to the C power generation unit 100 has reached about 5 to 7 times the theoretical equivalent ratio required for the battery reaction. For this reason, there is a problem that the scale of the air compressor 460 increases, and the amount of FC power generation with respect to the amount of air consumption decreases.

The combined power plant 10 shown in FIG.
00, the reaction gas heating unit 300, particularly the air heater 3
At 40, a large amount of air is supplied to the FC power generation unit 10 as described above.
0, the amount of exhaust heat of the FC power generation unit 100 consumed here becomes large, and G
The temperature at the inlet of the T power generation unit 400 decreases, and the GT power generation unit 40
There is a problem that the output of 0 decreases. further,
In order to increase the output in the GT power generation unit 400, the combustor 4
If the fuel gas F ₄₀₀ is supplied to the fuel cell 20, the excess fuel gas F
_{It is said that 400} is consumed also in places other than the FC power generation unit 100, and the power generation efficiency of the entire plant is reduced together with excess air being consumed in addition to the fuel cell reaction.

The present invention has been made in view of the above problems, and can maintain a fuel cell at a desired operating temperature, achieve high power generation efficiency, and further reduce the heat generated by the FC power generation unit 100. An object of the present invention is to provide a combined cycle power plant with high plant efficiency by efficiently collecting and using the same.

[0024]

For this reason, the first combined cycle power plant of the present invention has the following means.

(1) An FC power generation unit for generating power by electrochemically reacting air and fuel gas via an electrolyte, and a high-temperature drive by burning air cathode exhaust gas and fuel electrode exhaust gas discharged from the FC power generation unit A GT power generation section comprising a gas turbine having a combustor for generating gas, and a compressor for compressing the supplied air to be supplied to an air electrode of the FC power generation section, and a power generator for operating a power generator for outputting power. And a steam turbine driven by steam generated by exhaust gas discharged from the gas turbine to the GT exhaust heat recovery unit, and a steam turbine that outputs power, a plurality of FC power generation units are arranged in series, Exhaust gas discharged from the power generation unit was supplied to the subsequent FC power generation unit to generate power.

(A) As a result, since all the air supplied to the FC power generation units in each stage is supplied by one compressor, the compression power per FC power generation unit is the radix of the FC power generation units. , The compression power per output of the FC power generation unit can be reduced, and the plant efficiency can be improved. In addition, since the exhaust gas of the first-stage FC power generation unit is supplied to the next-stage FC power generation unit and power is generated using this exhaust gas, high-temperature supply of air / fuel gas to be supplied to the next-stage FC power generation unit, particularly, fuel High-temperature supply of air having a larger supply flow rate than that of gas supply becomes easier, and the power generation efficiency of the FC power generation unit can be improved. In this respect, the plant efficiency can be improved.

Further, a plurality of FC power generation units are arranged in series, and the exhaust gas heated by the preceding FC power generation unit is supplied to the subsequent FC power generation unit. Can be increased even when a reaction gas heating section for heating the air / fuel gas is provided, and the fuel gas supplied to the reburning of the combustor to bring the gas turbine into an efficient operation state can be increased. The volume can be reduced, which can also increase plant efficiency.

The second combined cycle power plant of the present invention employs the following means in addition to the means (1) described above.

(2) Air and fuel gas interposed between the gas turbine and the GT exhaust heat recovery section and supplied to the first-stage FC power generation section are preheated by exhaust gas discharged from the gas turbine, and preheated. The GT exhaust heat recovery unit is provided with a preheat regeneration unit that discharges to a steam generation unit that generates steam for driving a steam turbine by using the exhaust gas later.

(B) Thus, in addition to the above (a), F
Since a plurality of C power generation units are arranged in series and only the first FC power generation unit is heated by the preheating regeneration unit, particularly air supplied in a larger amount than the fuel gas, the exhaust gas from the upper FC power generation unit In addition to reducing the capacity of the reaction gas heating section that heats the air, especially the capacity of the air heating section, the temperature of the exhaust gas supplied to the combustion section from the final stage FC power generation section can be increased, and The amount of combustion gas supplied for firing can be further reduced, and plant efficiency can be further improved.

The third combined cycle power plant of the present invention employs the following means in addition to the means of the above (1).

(3) First from the air supply unit and the fuel supply unit
A reaction gas heating unit capable of heating the air supplied to the stage FC power generation unit and the fuel gas supplied to the first stage FC power generation unit or the FC power generation unit of each stage to a required temperature can be provided to perform preheating. The number of stages, specifically, an FC power generation unit having three or more stages was provided, and the preheating regeneration unit could be omitted.

(C) Thus, in addition to the above (a), the temperature of the exhaust gas supplied to the combustor from the FC power generation unit at the final stage can be increased, and the exhaust gas is supplied for reheating the combustor. The amount of fuel gas can be reduced,
The amount of steam that can be generated by the exhaust gas discharged from the gas turbine to the GT exhaust heat recovery unit can be increased, and the amount of power generated by the steam turbine that is driven by the steam generated by the steam generator and outputs power can be increased. The power generation efficiency of the combined cycle power plant can be further improved.

The fourth combined cycle power plant of the present invention employs the following means in addition to the above-mentioned means (1).

(4) At least the first of the FC power generation units
Cooling FC with cooling system in which the stage FC power generation unit can be operated with lower temperature air and fuel gas than the conventional FC power generation unit
The power generation unit was used.

(D) As a result, in addition to the above (a), the temperature of the air and the combustion gas supplied to the first stage cooling FC power generation unit can be reduced from 950 ° C. to 600 to 700 ° C. The reaction gas heating unit only needs to be installed with the first stage air heating unit for heating the air supplied from the compressor and the fuel gas heating unit for heating the fuel gas supplied to the second and subsequent FC power generation units. , The temperature of exhaust gas supplied to the combustor from the final stage FC power generation unit can be increased,
It is possible to reduce the amount of fuel gas supplied for reheating of the combustor, and furthermore, it is possible to generate reformed steam for reforming the fuel gas from exhaust gas from the preceding FC power generation unit, The amount of steam that can be generated by the exhaust gas discharged to the GT exhaust heat recovery unit can be increased, and the amount of power generated by the steam turbine that is driven by the steam generated by the steam generator and outputs power can be increased. The power generation efficiency of the combined cycle power plant can be further improved.

The fifth combined cycle power plant of the present invention employs the following means in addition to the above-mentioned means (1).

(5) A plurality of power generation units including an FC power generation unit or a cooled FC power generation unit are arranged in series, and the fuel electrode exhaust gas and the air electrode exhaust gas discharged from the former stage power generation unit to the latter stage power generation unit are separately separated. The combined power generation plant according to claim 1, wherein power is supplied to the fuel electrode and the air electrode of the subsequent power generation unit to generate power. The fuel electrode exhaust gas and the air electrode exhaust gas which are separately supplied to the fuel electrode and the air electrode of the latter-stage power generation unit to generate power, respectively, are provided on the downstream side of the last-stage power generation unit. After combustion in the combustion section, it may be supplied to the combustor, or separately to the combustor together with the fuel gas supplied from the fuel gas supply section to the combustor in order to control the combustor outlet temperature. You may make it supply.

(E) As a result, the temperature of the cathode exhaust gas discharged from the front-stage power generation unit to the air electrode of the rear-stage power generation unit becomes high,
In addition to the functions and effects similar to the above (a) to (d), the fuel gas supplied to the power generation units of each stage is added to the high temperature anode exhaust gas discharged from the former power generation unit to the fuel electrode of the latter power generation unit. Since the fuel gas heating section is mixed and heated, the size of the fuel gas heating section can be reduced, and the unreacted fuel gas discharged together with the fuel electrode exhaust gas is used as the fuel gas for the post-stage power generation section. The supplied fuel gas can be reduced.Furthermore, since the anode exhaust gas supplied to the post-stage power generation unit fuel electrode contains steam generated during power generation, this steam is supplied to the post-stage power generation unit. Since it can be used as reformed steam of the supplied fuel gas, the amount of reformed steam for reforming the fuel gas supplied to the second and subsequent stages of the power generation unit can be reduced or reduced to zero. Further improve power generation efficiency of power plants It can be.

[0040]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a combined cycle power plant according to the present invention will be described with reference to the drawings. In the following description, the same or similar members as those shown in FIG. 10 are denoted by the same reference numerals, and description thereof will be omitted.

FIG. 1 is a block diagram showing a first embodiment of the combined cycle power plant according to the present invention.

As shown in the figure, the combined cycle power plant 10 of the present embodiment is mainly composed of a two-stage FC power generator in which a first-stage FC power generator 21 and a second-stage FC power generator 22 are connected in series. FC power generation unit 2 that generates power by an electrochemical reaction between the introduced fuel gas f and oxygen in the air a _61a
0, the fuel gas f unreacted discharged from the FC power generation portion 20, by re-burning the gas g ₂₀ including air a _61a, first-stage combustion unit 31, further to a high temperature, the second stage combustion section 32 , A fuel gas f supplied to each FC power generation unit 20 with exhaust gas g ₃₁ and g ₃₂ discharged at a high temperature in the combustion unit 30 and air a _61a supplied to the first stage FC power generation unit 21
A reaction gas heating unit 60 including a first-stage reaction gas heating unit 61 and a second-stage reaction gas heating unit 62 for heating the fuel gas, and a fuel gas to which an exhaust gas g62 discharged from the second-stage reaction gas heating unit ₆₂ is added by burning the f _c, heating, performs power generation is driven by the exhaust gas g ₄₂₀ which was raised, first stage FC power generation portion 21 to supply GT power generation portion 40 compresses the introduced air a, A fuel gas supply unit 80 that supplies a fuel gas f to each FC power generation unit 20 and GT power generation unit 40,
An air supply unit 700 that supplies the air _a61a to the power generation unit 40,
Fuel gas supply unit 80 in the exhaust gas g ₄₀ from GT power generation portion 40
And preheating reproducing unit 50 for preheating the fuel gas f and air a ₄₆₀ supplied from the air supply unit 700 is provided, the vapor s ₁ for fuel reforming in the exhaust gas g ₅₀ from the preheating reproduction unit 50, s
₂₎ and steam S for driving the steam turbine.
_And a GT exhaust heat recovery unit 70 for generating _T.

The FC power generation unit 20 has a first-stage FC power generation unit 21 similar to the FC power generation unit 100 shown in FIG. 10 installed at the forefront, and is connected in series to the downstream side of the FC power generation unit 21. , Exhaust gas g ₂₁ discharged from the first-stage FC power generation unit ₂₁
The second-stage FC power generation unit 22 that introduces the above is provided. In the present embodiment, the FC power generation unit 20
Shows a two-stage structure, but depending on the amount of air supplied to the first-stage FC power generation unit 21, an n-th stage FC power generation unit (where n > 3) is provided, and the reaction gas heating at the last stage is performed. Part 62
An n-th stage FC power generation unit 20n that makes the oxygen concentration in the exhaust gas discharged from n close to 0% can be provided.

However, in the following description of the present embodiment, in order to simplify the explanation, in the case where the n-th stage FC power generation unit 2n is further disposed downstream of the second-stage FC power generation unit 22, F arranged downstream of the second-stage FC power generation unit
The C power generation units 20 and n are represented by a second-stage FC power generation unit 27, and are installed downstream of the second-stage FC power generation unit 22 in conjunction with providing three or more stages of the FC power generation units 20 described later. The combustion unit 30n and the reaction gas heating unit 60n are represented by the second stage combustion unit 22 and the second stage reaction gas heating unit 62.

As described above, a plurality of stages are provided in series.
Each of the FC power generation units 20 is provided with natural gas or the like.
Fuel gas f₁And air a_61aOxygen in the solid oxide
The inside that generates electricity by causing an electrochemical reaction through the electrolyte
It has a stack of reformed SOFC. Also, the first stage
The FC power generation unit 21 has a fuel reforming temperature (for example, 950 ° C.).
High-pressure air heated to_61aAnd from the fuel supply unit 80
Supplied fuel gas f₁To reformed steam₁Are mixed
Reformed fuel gas (f₁
+ S ₁)_61fAre introduced and these initiate an electrochemical reaction.
We will use a conventional FC power generation unit that generates power.
Caught.

[0046] Further, in the second stage FC power generation section 22 and the exhaust gas g ₆₁ from the first stage FC power generation portion 21, reforming steam s ₂ to the fuel gas f ₂ supplied from the fuel supply unit 80 are mixed,
Similarly, the reformed fuel gas (f ₂ +
s ₂ ) A conventional FC power generation unit that also generates electric power by introducing _62f is adopted. In the third and subsequent stages, F
Similarly, in the case where the C power generation unit 20n is provided, similarly, the exhaust gas g _30n-1 and the reformed steam (f + s) _60n-1f from the preceding-stage FC power generation unit 30 are introduced to similarly generate electric power. FC similar to 1st and 2nd stage FC power generation units 21 and 22
A power generation unit 20n is provided. Further, the exhaust gas g ₂₀ from the FC power generation portion 20 to generate power, but also to high temperatures After power generator with air cooling is discharged from the FC power generation portion 20 to the next wake equipment.

Next, the combustion unit 30 is disposed downstream of each FC power generation unit 20 provided in a plurality of stages, respectively.
And oxygen in the fuel gas f and air a _61a unreacted in the exhaust gas g ₂₀ discharged from the preceding FC power generation portion 20 by burning hot combustion gases g ₃₀ a (g _31, g ₃₂ ......) It is for generating.

Each of the reaction gas heating units 61 and 62 includes a fuel gas heating unit 61f and a air heating unit 61f.
a, 62a, and the fuel gas heating units 61f, 6
2f is a reformed fuel gas (f ₁ + s ₁ ) _61f supplied to the fuel electrode of each stage of the FC power generation unit 20 therein.
(F ₂ + s ₂ ) _62f is _converted into reformed fuel gas (f ₁ + s ₁ ) ₅₄₀ , (f ₂ + s ₂ ) by utilizing the heat generated by the FC power generation unit 20 and the heat generated by the combustion units 31 and 32 in the preceding stage. _The temperature of _i is raised to (f ₁ + s ₁ ) _{61 f} and (f ₂ + s ₂ ) ₆₂ f at desired reforming temperatures (for example, 950 ° C.) to be introduced into the FC generator 20.

However, the reformed fuel gas (f ₁ + s ₁ ) _{540 which} is heated by the fuel gas heating unit 61f disposed downstream of the first stage FC power generation unit 21 and the downstream side of the second stage FC power generation unit 22 The finished temperature is the same as that of the reformed fuel gas (f ₂ + s ₂ ) heated by the disposed fuel heating section 62f, but the temperature conditions and flow rates at the inlets of the fuel gas heating sections 61f and 62f are different. Therefore, the specifications of the fuel gas heating unit 61f and the fuel gas heating unit 62f are different. On the other hand, the air heating units 61a and 62a
The air a _61a supplied to the air electrode 1 is supplied to the combustion section 3 of each stage.
The exhaust gas heated in steps 1 and 32 is sequentially heated.

The air flow supplied to the air heating units 61a and 62a is the air flow supplied to the first-stage FC power generation unit 21 and, as described above, flows downstream of the FC power generation units 21 and 22, respectively. Fuel gas heating sections 61f, 62f provided
Of the exhaust gas g ₂₁ , g ₂₂ discharged from the FC power generation units 21, 22 in each stage,
The temperature of the exhaust gas flowing into the second-stage FC power generation unit 22 is 950
The air heating units 62a, 62
1a, the temperature of the first-stage air heating unit 61 is increased.
It is necessary to set the temperature so that the outlet temperature of “a” becomes 950 ° C.

Next, the GT power generation section 40 is a reaction gas of the last stage.
Exhaust gas g discharged from the heating unit 62 ₆₂Fuel supply section 80
Fc from the exhaust gas g₆₂Acid remaining in
Exhaust gas g₆₂To the specified turbine inlet temperature
Combustor 420 and its exhaust gas g₄₂₀so
It is driven and introduced from the air supply unit 700 to compress the air a.
Air compressor 46 that supplies the compressed air to the first-stage FC power generation section 21
0, the generator 4 with the surplus power that drives the air compressor 460
A gas turbine 440 that drives the motor 80 to generate electric power;
And a similar configuration of the GT power generation unit 400 shown in FIG.
Are provided.

Next, the preheating regeneration section 50 is provided with a heat recovery circuit (to be described later).
And is discharged from the gas turbine 440.
Exhaust gas g₄₄₀The air a discharged from the compressor 460
₄₄₀Preheating regeneration section 500 for heating the fuel and fuel supply section 80
Fuel gas from₁And a GT exhaust heat recovery unit 70 to be described later.
From HRSG 71 for generating steam for reforming provided in the plant
Steam s₁And supplied to the first-stage reaction gas heating unit 61
Reformed fuel gas (f ₁+ S₁)₅₄₀To the intermediate temperature
And a fuel gas preheating reheating unit 540 to be heated.

The GT exhaust heat recovery section 70 is provided with the preheating regeneration section 50 and the reforming steam generator 71 for generating the reforming steam s ₁ and s ₂ . Steam generator (HRG)
S) The steam is generated in 72, and a steam turbine not shown is driven to generate surplus steam for generating electric power.

The combined power generation plant 10 of the present embodiment
As described above, the first stage
The fuel gas of about 15 ° C. supplied to the fuel electrode of the FC power generation unit 21
F ₁Is the reforming steam s from the reforming steam generator 71.₁When
Mixed and reformed fuel gas (f ₁+ S₁) Becomes fuel gas
The preheating regenerator 540 and the combustion gas heating unit 61a
Heated to 950 ° C. reformed fuel gas (f₁+ S₁)
_61fSupplied as Further, the air supply unit 700
A introduced into the compressor 460 from the compressor 460
After the temperature was raised to 00 ° C., the air preheat regenerator 520
The air heater 62a and the air heater 61a reduce the temperature to 950 ° C.
Heated air a raised in temperature_61aAnd the first stage FC
It is supplied to the air electrode of the electric part 21.

In the first-stage FC power generation section 21 in which the reformed fuel gas (f ₁ + s ₁ ) _61f and the heated air a _61a are supplied to the fuel electrode and the air electrode, respectively, the reformed fuel gas (f. f ₁ + s _{1) 61f} is reacted on a catalyst of the fuel electrode, to produce hydrogen and carbon oxides. Since this reaction is an endothermic reaction, the first-stage F
The heat generated by the C power generation unit 21 can be absorbed. Also,
Oxygen in the compressed air a _61a introduced into the air electrode becomes O ²⁻ ions, conducts inside the solid oxide electrolyte, moves to the fuel electrode, and causes an electrochemical reaction with the above-described hydrogen and carbon monoxide, Produces water and carbon dioxide.

Here, of the reaction heat, the amount obtained by subtracting the amount based on the internal resistance of the battery from the amount corresponding to the change in free energy is converted into electric energy (DC power).
The remainder will be generated as heat. The generation of water or carbon dioxide at the fuel electrode is an exothermic reaction, and the generated heat is air-cooled and maintained at the FC operating temperature (for example, 1050 ° C.).

The fuel electrode exhaust gas and the air electrode exhaust gas that have passed through the first-stage FC power generation unit 21 are mixed, and the exhaust gas g ₂₁
Is introduced into the first stage combustion unit 31 constituting the combustion unit 30. In this combustion section 31, and the oxygen O ₂ excess air discharged hydrogen generated in the fuel gas f ₁ and the fuel electrode of the unreacted remaining in the exhaust gas, the carbon monoxide and the air electrode,
Readily undergo combustion reaction under a high temperature, combustion gas g ₃₁ next, is introduced into the first stage reaction gas heating unit 61, the combustion gas heating unit 61f and the air heating unit 6 of the reaction gas heating section 61
Fuel (f ₁ + s ₁ ) ₅₄₀ and air a passing through 1a
_The fuel is exchanged with _62a, and these are both introduced into the first-stage FC power generation unit 21. The fuel for reforming at the FC operating temperature (f ₁ + s ₁ ) _61f
After being converted to the air a _61a , the air is supplied to the air electrode of the second-stage FC power generation unit 22 in a high-temperature state of the FC operation.

The second-stage FC power generation section 21 into which the exhaust gas g ₆₁ discharged from the first-stage reaction gas heating section 61 is introduced is converted into a fuel gas f ₂ of about 15 ° C. supplied from a fuel supply section 80. The reforming steam s ₂ from the quality evaporator 71 is added, and the second
The reforming fuel gas (f ₂ + s ₂ ) _62f heated in the second-stage reaction gas heating section 62f is introduced, and the second-stage FC power generation section 22
It reacts at the anode in the unit to produce hydrogen and carbon monoxide. Further, unreacted oxygen in the exhaust gas g ₆₁ is supplied to the air electrode, similarly to the first stage FC power generation portion 21, the newly introduced reformed fuel gas (f ₂ + s _{2) 62f} and an electrochemical reaction raised, together with generating electric power, the fuel electrode exhaust gas and an air electrode exhaust gas passing through the FC power generation portion 22 are mixed, is introduced as an exhaust gas g ₂₂ to the second stage combustion section 32.

[0059] In this combustion section 32, the oxygen O ₂ of the unreacted fuel gas f ₂ component and air a _61a unreacted remaining in the exhaust gas g _32, readily combustion reaction at elevated temperature of the original next combustion gas g ₃₂ undergoes, is introduced into the reaction gas heating unit 62, passes through the combustion gas heating unit 62f and the air heating portion 62a of the reaction gas heating unit 62, reforming fuel (f ₂ + s
₂ ) and heat exchange with the air a ₅₂₀ to form the reforming fuel gas (f
₂ + s ₂ ) is introduced into the second-stage FC power generation unit 32 to make high-temperature reformed fuel (f ₂ + s ₂ ) _62f, and air a ₅₂₀ supplied from the air preheat regenerator 420 is heated to the first-stage air. In the section 61a, the first-stage FC power generation section 21 is heated to a desired temperature. Thus, the reforming fuel gas (f ₂ +
s ₂ ) and the air a ₅₂₀ are heated to reduce the temperature, and the exhaust gas g discharged from the second reaction gas heating unit 62
₆₂ is supplied to the combustor 420 of the GT power generation unit 40.

The combustor 420 has a fuel supply section 8.
0 and so the fuel gas f _c is supplied from the combustor 420, and the oxygen in the air a _61a remaining in the fuel f _c and the exhaust gas in g ₆₂ burns at a predetermined temperature Is supplied to the gas turbine 440 as the combustion gas of the first stage, the output is generated, and the compressor 460 is driven to drive the first stage FC
The air a supplied to the power generation unit 21 is compressed, and the generator 480 is operated to generate electric power.

The exhaust gas g ₄₄₀ discharged from the gas turbine 420 is supplied to a preheating regeneration unit 50 provided in the GT exhaust heat recovery unit 70, and is supplied to the compressor 46 by the air preheating regeneration unit 520.
The air a ₄₆₀ of about 400 ° C. compressed and discharged at 0 is turned into air a ₅₂₀ heated to the inlet temperature of the second-stage air heating section 62 a, and the fuel gas preheating regenerator 540 outputs the fuel from the fuel supply section 80. The supplied reforming fuel gas (f ₁ + s ₁ ) in which the supplied fuel gas f ₁ and the reforming steam s ₁ from the reforming steam generator 71 are mixed is supplied to the first-stage fuel gas heating section 61f.
Reforming fuel gas heated to the inlet temperature (f ₁ +
s ₂ ) _Set to ₅₄₀ .

Further, an exhaust gas g ₅₀ (about 500 ° C.) discharged from the preheating regeneration section 50 is supplied to a first-stage FC power generation section 21 by a reforming steam generator 71 provided in a GT exhaust heat recovery section 70.
They are mixed before the fuel gas f ₁ supplied to is supplied to the fuel gas preheating unit 540, the reforming steam s ₁ to the fuel gas f ₁ to the reforming fuel gas (f ₁ + s _1), and a second stage F
They are mixed before the fuel gas f ₂ supplied to the C power generation section 22 is supplied to the combustion gas heating unit a _62f of the second stage, reforming of the fuel gas f ₂ to the reforming fuel gas (f ₂ + s ₂₎ Quality steam s ₂
Generate.

The surplus exhaust gas g supplied to the GT exhaust heat recovery section 70 and not used for generating the reformed steams s ₁ and s _2.
50 is supplied to a steam generator (HRSG) 72 installed in parallel with the reforming steam generator 71, and generates steam s _T for driving a steam turbine that performs power generation (not shown). In this way, the reformed steam s ₁ , s ₂ and the steam turbine driving steam s _T are generated, and the exhaust gas g ₇₀ whose temperature is reduced to about 100 ° C. is discharged from the chimney 580 to the outside.

The combined cycle power plant 10 of the present embodiment has
As shown in FIG. 10, a conventional combined cycle power plant has one compressor 460 for supplying air A to the FC power generation unit 100, whereas one compressor 460 is provided for one FC power generation unit. Two units 20 are provided in series, and the exhaust gas g ₂₁ of the first-stage FC power generation unit ₂₁ is used as air to be supplied to the air electrode of the second-stage FC power generation unit 22.
1. Since one compressor 460 is commonly used for the FC power generation unit 21, the compression power per FC power generation unit can be reduced to about 約 divided by the number of bases. Reduction in compression power per output can be reduced.

It is to be noted that the final stage is not provided with two FC power generation units.
O in exhaust gas from FC power generation unit 20n _TwoTo the lower limit of stability
Many FC power generation units are arranged in series, and FC
The compression power of the power generation unit 20 is reduced to about 1 / n,
It can also be done. Exhaust gas g_nO inside_TwoThe lower limit of stability
In this case, the exhaust gas g from the final stage FC power generation section is added.
The heated combustor 420 receives the supplied fuel gas f_cFire
Air required for baking is supplied separately or the combustor 420 is
Without installation, exhaust gas at 950 ℃_nGas turbine 440
To operate gas turbine efficiency with low efficiency.
It is necessary.

Further, the exhaust gas of the upper stage FC power generation unit 20 is introduced into the air electrode as air of the next stage FC power generation unit 20, so that the air supplied to the second stage FC power generation unit is heated. There is no need to install an air heating unit corresponding to the first-stage air heating unit.

The combined cycle power plant 1 of the present embodiment
At 0, the air input to the first stage FC power generator 21 is 950 ° C.
In this case, the temperature of the compressor discharge air a ₅₂₀ at about 400 ° C. is divided into several times, and the temperature is increased in the preheating regeneration section 50 and the two reaction gas heating sections 61 and 62. Therefore, it is possible to reduce the degree of cooling of the exhaust gas discharged from the FC power generation unit 20 per unit, increase the exhaust temperature, and supply air at a temperature suitable for operation of the subsequent FC power generation unit 20,
Furthermore, the gas turbine 440 from the final stage FC power generation unit
Since the temperature of the exhaust gas sent to the fuel cell can be raised to a high temperature (1000 ° C. or higher), the amount of GT fuel decreases, which also improves the efficiency η _{cc of the} combined cycle power plant.

That is, the air a ₅₂₀ (about 550 ° C.) discharged from the air compressor 460 is supplied to the air heating unit 3 shown in FIG.
When heating to 950 ° C. with only 40, the air heating unit 340 increases the temperature to + 400 ° C. (550 → 950
Since the heat exchange ° C.), for exhaust gas discharged from the air heating unit 340 is as low as 700 to 800 ° C., since the fuel gas f _c for add焚専combustor 420 increases η
_{Although the cc} is low, the combined cycle power plant 10 of the present embodiment is
Then, such inconsistency can be resolved, and FIG.
Although the efficiency η _cc of the conventional combined cycle power plant shown in FIG. 5 is about 50%, the present embodiment can improve the efficiency η _cc to about 55% or more.

Next, FIG. 2 is a diagram showing a second embodiment of the combined cycle power plant of the present invention. The combined cycle power plant 11 of the present embodiment is different from the combined cycle power plant of the first embodiment shown in FIG. 10, a third-stage FC power generation unit 23, a third-stage combustion unit 33, and a third-stage reaction gas heating unit 63 are provided.
In the first embodiment, the preheating regeneration unit 50 provided in the GT exhaust heat recovery unit 70 is deleted, and the preheat regeneration unit 50 is supplied from the fuel supply unit 80 to the first to third power generation units 21, 22, 23, respectively. that the fuel gas f _1, f _2, f _3, after mixing together the reformed vapor s in the fuel gas f supplied from the fuel supply unit 80 outlet, reformed fuel gas (f ₁ + s ₁₎ ,
The flow is divided into (f ₂ + s ₂ ) and (f ₃ , s ₃ ).

That is, the first-stage air compressor 460
The amount of air supplied to the power generation unit 21 is required for one FC power generation unit.
4 to 5 times the required air ratio is supplied.
By providing the power generation unit 23, the third-stage reaction
The gas heating unit 63 can be installed, whereby
Compressed air a of about 400 ° C. discharged from the compressor 460
₄₆₀Is + 200 ° C. × 3 =
A temperature rise of 600 ° C. can be performed.
To be provided in the GT exhaust heat recovery unit 700,
Necessary for the first-stage power generation unit 21 even if the heat regeneration unit 50 is not provided
The reaction gas can be heated up to 950 ° C.
Emissions from FC power generation unit 20 per FC power generation unit
Reduce the degree to which gas gas g is cooled, and heat each reaction gas.
The exhaust gas g discharged from the section 30 is maintained at a high temperature, and
So that it can be supplied to the air electrode of the FC
Was.

In the combined cycle power plant of the present embodiment, the first reforming fuel gas (f ₁ + s ₁ ) _61f supplied to the first-stage FC power generation section 21 is heated to 950 ° C. by reducing the heating capacity of the stage air heating unit 61a, the exhaust gas g ₃₁ discharged from the combustion unit 31 as well as to supply more to the fuel gas heating section 61f, the heating capacity of the first stage air heating unit 61a Reduction of the second
Cover by the heating of the stage air heating unit 62a and the third stage air heating unit 63a. The reformed fuel gas (f ₂ +) supplied to the second-stage FC power generation unit 21 and the third-stage FC power generation unit 22, respectively.
s ₂ ), (f ₃ , s ₃ ) and approximately the same amount of reformed fuel gas (f ₁
+ S ₁ ) is supplied to the first-stage FC power generation unit 21.

Thus, the same operation and effect as those of the first embodiment can be obtained. In addition, the third-stage FC power generation unit 23 and the third-stage reaction gas heating unit 63 are provided. By eliminating 50, the gas turbine 44
The exhaust gas g ₄₀ because it can heavily used for power generation by the steam turbine from 0, the eta _cc can be increased to about 60%.

Next, FIG. 3 is a block diagram showing a third embodiment of the combined cycle power plant according to the present invention. As shown in the drawing, in the combined cycle power plant of the present embodiment, the first embodiment,
As in the second embodiment, the FC power generation units are connected in series in a plurality of stages, and the air system of the subsequent FC power generation unit is connected to the upper exhaust system, so that the thermal energy generated in the upper FC power generation unit is used. At the same time, the first-stage FC power generation section supplies a fuel gas and air at a temperature of 600 to 700 ° C. lower than 950 ° C. and recovers heat from the FC power generation section 20 to form a reaction gas heat exchange section 2.
4, a cooling-in type cooling first stage F which is heated to 950 ° C. and supplied to the fuel cell to generate electricity.
C power generation unit 21A, and each stage FC power generation unit 2
Air heating unit 61a for supplying air at 950 ° C.
Is a cooling first-stage FC power generation unit 21 that is a first-stage FC power generation unit.
A is provided only on the downstream side of A.

That is, the combined cycle power plant 1 of the present embodiment
In the second stage, the first stage FC power generation unit operates in a low temperature state (for example, 6
Reforming fuel gas (f
₁ + s ₁ ) _61f , and a temperature (950) suitable for supplying the air a _61a at the same temperature and supplied from the first-stage air heating section 61a to the fuel electrode and the air electrode, respectively.
° C), and a cooling first-stage FC power generation unit 21A provided with a reaction gas heat exchange unit 24 composed of a fuel gas heat exchange unit and an air heat exchange unit, which cools the FC body.

[0075] Thus, the cooling air a _{46 0} supplied from the compressor 460 to the first stage power generation unit 21A, an air heating unit 62a as in the first embodiment and the second embodiment of the implementation, 6
3a or the air of about 400 ° C. discharged from the air compressor 460 by the first-stage air heater 61a without being heated by the air preheating regeneration unit 520, is cooled to a low temperature of 600 to 700 ° C. The first stage Since the power can be supplied to the power generation unit 21A, the installation of the second-stage and third-stage air heating units 62a and 63a or the air preheating regeneration unit 520 provided in the first and second embodiments becomes unnecessary.

In the present embodiment, the first-stage reaction gas
The downstream side of the heating section 61, the second-stage fuel gas heating section 62f and
A steam generator is provided downstream of the third-stage fuel gas heating section 63f.
The water extracted from 72 is supplied to the reaction gas heating units 61 and 62.
f, 63f, and heated with reformed steam
s₁, S_Two, S_ThreeReforming steam generator 71f
₁, 71f_Two, 71f_ThreeIs provided.

As described above, the second-stage reaction gas heating section 62,
The third stage reaction gas heating unit 63 from the air heating portion 62a, by the air heating portion 63a can be eliminated, newly despite placing the steam reforming generator 71f _2, 71f _3, the supply of the combustor 420 The temperature of the exhaust gas g _71f3 to be _discharged can be increased. In the combustor 420, the exhaust gas g _71f3
From 400 ° C (950 → 1350 ° C)
To 150 ° C. (1200 → 1350 ° C.), which corresponds to the fuel gas f supplied to the combustor 420.
_This corresponds to reducing the amount of _c by 60% or more.

[0078] The exhaust gas g ₄₄₀ from the gas turbine 440, as in the second embodiment GT exhaust heat recovery unit 70
And the reforming steam s ₁ , s ₂ , and s ₃ by the reforming steam generator 71 are supplied to the first-stage reaction gas heating unit 61, the second-stage fuel gas heating unit 62 f, and the third-stage fuel gas exhaust g _61, g _62f from the heating portion 63f, by which is adapted to generate the g _63f, it is possible to increase the steam energy that can be generated by the steam generator 72,
The amount of power generated by a generator driven by a steam turbine (not shown) can be increased.

As described above, the combined power generation plug of this embodiment
In operation 12, the same operation and effect as in the first embodiment can be obtained.
In addition to the above, the first-stage FC
By using the power generation unit 21A, the first stage cooling FC power generation
Air a supplied to the section 21A _61aAnd reformed fuel gas
(S₁+ F₁)_61fCan be supplied at low temperatures.
And the second and third stage air heaters 62a, 63a or air
The installation of the preheating regeneration unit 520 becomes unnecessary.

The air heating section 62a and the air heating section 63
a can be eliminated, the temperature of the exhaust gas g _71f3 supplied to the combustor 420 can be raised by several hundred degrees Celsius,
Temperature rise can be reduced to give in, that further reduces the amount of fuel gas f _c supplied to the combustor 420. Further, a downstream side of the first-stage reaction gas heating unit 61,
Reforming steam s ₁ on the downstream side of the second stage fuel gas heating section 62f and the third-stage fuel gas heating unit 63f, s _2, s reforming steam generator to generate the ₃ 71f ₁ 71f _2, 71f ₃ is The exhaust gas g ₄₀ from the gas turbine 440
Is directly supplied to the GT exhaust heat recovery unit 70, is generated by the steam generator 72, and can increase the steam energy that can be used by the steam turbine, thereby increasing the amount of power generated by the generator driven by the steam turbine. Therefore, the efficiency of the combined cycle power plant can be further improved as compared with that of the second embodiment.

Next, FIG. 4 is a block diagram showing a fourth embodiment of the combined cycle power plant according to the present invention. As shown in the figure, in the present embodiment, as shown in the first to third embodiments, the first-stage FC power generation unit 21 to the third-stage FC
Although the power generation units 23 are connected in series, each FC power generation unit 2
The exhaust gas of the air system and the exhaust gas of the fuel system respectively discharged from 1 to 23 are not mixed, and the air system of the lower-stage FC power generation unit is connected to the air discharge system of the upstream-stage FC power generation unit. The fuel system is connected to the fuel discharge system of the upstream stage FC power generation unit, and the oxygen in the exhaust gas discharged from the air discharge system and the fuel gas in the exhaust gas discharged from the fuel discharge system become the third.
The mixture was mixed on the downstream side of the stage FC power generation unit 23, burned in the combustion unit 30A, and supplied to the combustor 420.

Normally, fuel gas supplied to the FC power generation unit
Is necessary for the reaction at the fuel electrode in the FC power generation unit
The surplus (for example, 10%) will be injected in
Therefore, these surplus fuels are transferred to the post-FC power generation section.
That can be used as fuel gas for
You. As shown in FIG.
The air “a” introduced at 0 is compressed to about 400 ° C.
After the temperature is raised, the air preheating regenerator 20 and the air heating unit 62
a, the temperature is raised to the reforming temperature (950 ° C) by the air heater 61a.
Heated air a raised in temperature _61aAnd the first stage FC
It is supplied to the air electrode of the electric part 21.

The fuel gas f ₁ supplied from the fuel supply unit to the fuel electrode of the first-stage FC power generation unit 21 is heated by the fuel gas preheating regenerator 540, and then the reforming steam generator 71. After being mixed with the reforming steam s ₁ from the fuel gas and becoming the reforming fuel gas (f ₁ + s ₁ ) and heated by the first-stage FC power generation unit 21 and the combustion gas heating unit 61f, the 950 ° C. reforming fuel The gas (f ₁ + s ₁ ) is supplied as _61f . Reforming fuel gas (f ₁ + s ₁ ) _61f and heated air a _61a
First stage FC supplied to fuel electrode and air electrode respectively
In the power generation unit 21, the reforming fuel gas (f ₁ + s ₁ ) _61f introduced into the fuel electrode reacts on the catalyst of the fuel electrode to generate hydrogen and carbon monoxide.

Since this reaction is an endothermic reaction, the heat generated by the FC power generation unit 21 can be absorbed by the internal reforming reaction. Also, the compressed air a introduced into the air electrode a
Oxygen in _61a becomes O ²⁻ ions and conducts through the solid oxide electrolyte to cause an electrochemical reaction with these hydrogen and carbon monoxide to generate water and carbon dioxide. Here, of the heat of reaction, the amount obtained by subtracting the amount based on the internal resistance of the battery from the amount corresponding to the change in free energy is converted into electric energy (DC power), and the remaining amount is generated as heat. Since the generation of water or carbon dioxide is an exothermic reaction, it is cooled by air. As a result, the temperature of the first-stage FC power generation unit 21 is maintained at a desired operating temperature (for example, 1050 ° C.).

The fuel passing through the first-stage FC power generation unit 21
Charge exhaust gas g₁And air electrode exhaust gas a ₁Is the first stage reaction gas.
The combustion gas of the reaction gas heating unit 61
Reforming passing through the heating section 61f and the air heating section 61a
Fuel (f₁+ S₁)₅₄₀And air a_62aHeat exchanged
And the reforming fuel (f₁+ S₁)₅₄₀And air a_62aTo
Reforming fuel (f) introduced into the first-stage FC power generation section 21₁+
s₁)_61fAnd air a_61aAnd the second stage F
In the high temperature state required for the C
Exhausted from the heating unit 61,
It will be supplied to the cathode and air electrode.

[0086] In the second stage FC power generation portion 22, the exhaust gas g ₁ from the first stage fuel gas heating unit 61f, reformed fuel gas f ₂ supplied from the fuel supply unit 80 in the second stage fuel gas heating unit reformed fuel gas vapors s ₂ is heated and mixed (f ₂
+ S ₂ ) is supplied, the reformed fuel gas is supplied to the fuel electrode, and the exhaust gas a ₁ from the first-stage air heating unit 62a is supplied to the air electrode, and the same electricity as in the first-stage FC power generation unit 21 is supplied. A chemical reaction occurs, and the fuel electrode exhaust gas g ₂ and the air electrode exhaust gas a ₂ are separately discharged.

The fuel electrode exhaust gas g ₂ is obtained by mixing a reforming fuel gas (f ₂ + s ₂ ) obtained by mixing the reforming steam s ₂ with the fuel gas f ₂ from the fuel supply section 80 in the second-stage fuel gas section 62f. after heating to a predetermined value, is supplied to the fuel electrode of the third stage FC power generation unit 23, also the cathode exhaust gas a ₂ is the air a ₅₂₀ from the air preheater reproducing unit 520 to the inlet temperature of the first stage air heating unit 61a After the temperature is raised to the maximum value, the air is supplied to the air electrode of the third-stage FC power generation unit 23 to cause the same electrochemical reaction as in the first-stage FC power generation unit 21, and the fuel electrode exhaust gas g ₃ and the air electrode exhaust gas a ₃ To discharge.

[0088] During the fuel electrode exhaust gas g _3, Because the first stage FC power generation portion 21 to the third stage generator section 23, so that a slight excess of the fuel gas as described above is supplied, the fuel gas f has remained, also in the air electrode gas a _3, the first stage FC power generation portion 21, the air required for the electrochemical reaction in the first stage FC power generation portion 21 to the third stage generator section 23 Air a is remaining because excess air over the amount is supplied,
Combustion occurs in the combustion section 30 </ b> A where these are supplied and mixed, and supplied to the combustor 420.

[0089] Thus, the fuel gas f _c supplied from the fuel supply unit 80 can be greatly reduced, thereby improving the efficiency of the combined cycle power plant. Further, in the combined cycle power plant of the present embodiment, as described above, the fuel to be supplied to the FC power generation unit is put in surplus as a result of the above-described configuration.
In addition to being able to use it as a fuel gas for the subsequent FC power generation unit, and because the exhaust gas g contains H ₂ O,
Fuel gas (f ₂ +) supplied to the stage FC power generation unit 22
s ₂ ) for reforming mixed with the fuel gas f ₂ to obtain s ₂ )
_{(2) The} amount of steam can be reduced.

Further, since excess steam also flows to the FC power generation unit at the subsequent stage, and H ₂ O due to combustion is also added, the third stage provided on the downstream side of the second stage FC power generation unit 22 depending on the balance. The subsequent FC power generation unit does not need to supply reformed steam, and the heat utilization rate can be expected to be further improved. That is, as described in the first to third embodiments, the fuel is discharged from the preceding FC power generation unit without being converted into heat in the combustion units 31 to 33 provided on the downstream side of the FC power generation units 21, 22, 23. Fuel can be used as a raw material for the subsequent FC power generation unit.

The first-stage fuel gas heating section 61f and the second
Reforming fuel gas (f ₂
+ S ₂ ), the temperature of the fuel gas supplied to the second-stage power generation unit 22 can be maintained, and the second-stage fuel gas heating unit 62f described above can be omitted. it becomes possible to omit the third stage fuel gas heating section 63f same reason to heat the fuel gas f ₃ is supplied to the third stage generator section 23.

In the above embodiment, the third stage power generation unit 2
Exhaust gas g discharged from 3_Three, A_ThreeIn the combustion section 31A
It is burned and sent to the combustor 420.
Third stage power generation directly to combustor 420, omitting firing part 30A
Air electrode exhaust gas a from the part 23 _Three, Fuel electrode exhaust gas g_ThreeAnd
And fuel gas f from the fuel supply unit 80_cEach
You can also make it. This is a traditional recycling
Technology (fuel-based anode recycling, air-based cathode
The fluid conditions equivalent to (recycling) are changed to the two-stage power generation unit 22 and later.
It can be considered that it is realized in the conventional FC power generation unit
Is not required, and
H of combustion products_TwoO for reforming steam (after
And especially in the third and subsequent FC power generation units 20
The generation of intermediate steam becomes unnecessary.

Next, FIG. 5 is a block diagram showing a fifth embodiment of the combined cycle power plant according to the present invention. As shown in the figure, in the present embodiment, as in the fourth embodiment, the air system of the downstream FC power generation unit is connected to the air discharge system of the upstream FC power generation unit, and the fuel of the upstream FC power generation unit is connected. the system was connected to the upstream stage FC power generation unit fuel exhaust system, the fuel gas in an exhaust gas discharged from the air discharge based oxygen and combustion exhaust system of exhaust gases in a ₃ discharged from the third stage separately FC power generation The fuel was supplied from the section 23 to the combustor 420. Also, the third stage F
Fuel gas g supplied from C power generation unit 23 to combustor 420
Some of the ₃ as a recycle gas g _r, the heat exchanger 92
And a recycle circulating fan 96.

The first-stage FC power generation unit has the third embodiment.
The first cooling that can be operated at low temperature adopted in the form
It is provided with a stepped power generation portion 21A, mixed gas of the reforming steam s ₁ that the recycle gas g _r generated in reforming steam generator from the recycling circulation section 90 (g _r +
s ₁₎ to a mixture of fuel gas f ₁ supplied from the fuel supply unit 80 fuel gas pre-reproduction unit 540 and the fuel gas heating section 61f, without passing 62f, heated exhaust heat recycling circulating gas g _r Low-temperature reforming fuel gas (f ₁ + g
_r + s ₁ ).

That is, the reaction gas heater for heating the reaction gas to supply it to the power generation unit is a low-temperature air a that heats the air a ₄₆₀ from the compressor 460 (about 200 ° C.) as in the third embodiment. Only the first-stage air heating unit 61a configured to supply the first-stage cooling unit 21A with _61a is used, and the air preheating regeneration unit 570 and the second-stage air heating unit 62a in the fourth embodiment can be omitted. I made it.

[0096] Further, a heat exchanger 92 provided in the recycling circulation fan 90 inlet, steam cooling first stage FC power generation in the recycled gas g _r branched from the steam and the fuel electrode gas g ₃ produced in the heat exchanger 92 together we cover the reforming steam supplied to the part 21A, the anode exhaust gas g _r in the combustor 420,
Cathode exhaust gas a ₃ without burning in the combustion section 30A, and to be directly separately introduced together with the fuel gas f _c from the fuel supply unit 80. Incidentally, the steam that is not used as the modifying vapor s ₁ of the steam generated in the reforming steam generator 92 is supplied to the steam turbine with the steam from the steam generator 72 so that to generate electrical power.

Thus, the same operation and effect as those of the fourth embodiment can be obtained.
Because of the stage power generation unit 21A, the preheating regeneration unit 50, the second stage steam heating unit 62, and the first and second stage combustion gas heating units 61
f, 62f can be omitted, whereby the pressure loss of the air and fuel gas supply system is further reduced, and each FC power generation unit 2
1, 2, 23 can be operated at a higher pressure to increase the power generation output, so that the combined power plant efficiency η _cc can be improved, the power generation amount can be increased, and the omission of devices such as the combustion unit 30A is combined. Thus, the manufacturing cost can be reduced.

[0098] Further, since the fuel gas reforming supplied to the cooling first stage power generation portion _{21A (f 1 + g r +} s 1) can be supplied at low temperatures, the heat exchanger 92 for heating it, can be miniaturized or omitted , and was raised reduced recycling circulation fan 91 inlet temperature and power savings, when steam generated by the heating of the recycle gas g _r is sufficient, steam s generated in surplus supply to the steam system generated by the steam generator 72 However, the efficiency of the combined cycle power plant η _cc can be further improved by charging the steam turbine to generate electricity from the steam turbine.
The water in the recycled gas g _r is a number up to 75 mol% as shown in 1 (in excess zero).

[0099]

(Equation 1)

FIG. 6 is a block diagram showing a sixth embodiment of the combined cycle power plant according to the present invention. As shown in the figure, similarly to the second embodiment, the FC power generator 30 includes a conventional first-stage FC power generator 31, a second-stage FC power generator 32, and a third-stage F power generator.
The fuel gas f ₁ , f ₂ , and f ₃ are supplied to the FC power generation unit 30 from the FC power generation units 31, 32, and 33 in the same manner as in the fifth embodiment. The exhaust gas g to be separated is separated into fuel electrode exhaust gas g ₁ , g ₂ , g ₃ and air electrode exhaust gas a ₁ , a ₂ , a ₃ and supplied to the FC power generation units 32, 33 and the combustor 420 at the subsequent stage. I made it.

The supply of air to the first-stage power generation unit 31 is performed in the same manner as in the second embodiment.
The air heaters 63a, 62a,
61a, about 400 ° C. discharged from the air compressor 460
Is sequentially heated by 200 ° C., and the first-stage power generation unit 31 is heated.
Is supplied with 950 ° C. air. Further, the extracted part is hot exhaust gas g ₃ discharged from the fifth embodiment similarly to the third stage FC power generation portion 23 of the embodiment, the recycle gas g _r that the extraction first stage heat exchanger 92A and the By supplying the heat to the two-stage heat exchanger 92B, the first stage F
C power generation unit 31, second stage FC power generation unit 32, and third stage FC
The fuel gases f ₁ , f ₂ , and f ₃ supplied to the power generation unit 33 are heated.

The cooling by the first-stage heat exchanger 91 is as follows.
As shown in the figure, fuel supplied to the first-stage FC power generation unit 21
Gas f₁Or as shown in the fifth embodiment.
When generating steam to be supplied to the steam turbine steam system
May be performed by heating the water. This
And the same as the combined power plant of the fifth embodiment shown in FIG.
In addition to the same functions and effects, the fuel gas f₁To
When used as a cooling medium for the first stage heat exchange 92A,
Fuel gas f₁To supply the fuel to the first-stage power generation unit 21,
Gas f ₁-Stage fuel gas heating unit 61 for adjusting the temperature to the supply temperature
f, the first stage fuel heating section 61f becomes smaller.
It can be modeled or omitted.

Further, by using the fuel gas f ₂ , f ₃ to the second-stage FC power generation unit 22 and the third-stage FC power generation unit 23 as a cooling medium for the second-stage heat exchanger 92B, it is possible to omit the first step heat exchanger 92A, which all of the fuel gas f _1, f _2, f ₃ by the would be preheated recycle gas g _r based in-li
Cooling caused by ne mixing can be prevented.

Further, the gas turbine 44 is installed in the combustor 420.
0 although the inlet temperature to the optimum temperature so as to supply the fuel gas f _c, the third stage FC power generation portion 23 when a zero bleed amount of the recycle gas g _r is supplied to the combustor 420 of most of the exhaust gas g ₃ is supplied as an exhaust gas g _4, also becomes possible to fc = 0 depending on the conditions, it is possible to enhance the power generation efficiency of the combined cycle power plant 15.

Next, FIG. 7 is a block diagram showing a seventh embodiment of the combined cycle power plant according to the present invention. As shown in the figure, in the combined cycle power plant 16 of the present embodiment, the fuel gas f ₁ supplied to the first-stage FC power generation unit 21 is the fuel gas f ₂ , f used in the second-stage FC power generation units 22 and 23. Supply including ₃ That is, in the fourth embodiment shown in FIG. 4, the fuel gas f supplied to each stage of the FC power generation unit 20 at 10% or more, and the three-stage FC power generation unit 20 as in the present embodiment, Fuel gas f _{1 at} which 300% is the maximum value
Is supplied to the first-stage power generation unit 21 so that the next-stage power generation unit 20 generates power using the remaining fuel gas f ₁ in the _first- stage FC power generation unit.

Thus, the fuel gas heating units 61f and 62 heating the fuel gases f ₂ and f ₃ supplied to the second and subsequent FC power generation units 22 and 23 required in the fourth embodiment.
Since the installation of the fuel gas f becomes unnecessary, and the fuel gas f ₂ , f ₃ is not mixed into the exhaust gas g ₁ , g ₂ discharged from the pre-stage FC power generation unit 20 in the sixth embodiment, The temperature reduction of the exhaust gas g supplied to the FC power generation units 22 and 23 is prevented, and the supply of the higher temperature exhaust gas makes the second
, The power generation efficiency of the third-stage FC power generation units 22 and 23 is improved,
Combined cycle power plant efficiency can be improved.

When the fuel gas f is insufficient in the subsequent FC power generation units 22 and 23, the fuel gas f is mixed and introduced in-line by appropriately using the techniques in the fourth and sixth embodiments. Good.

Next, FIG. 8 is a block diagram showing an eighth embodiment of the combined cycle power plant according to the present invention. As shown in the figure, in the combined cycle power plant 17 of the present embodiment, the fuel gas f ₁ supplied to the first-stage FC power generation unit is exhaust gas discharged from the third FC power generation unit 23 as in the fifth embodiment. g ₃
With heating in the first stage heat exchanger 92A and the first-stage combustion gas heating unit 61f for cooling the recycle gas g _r bled a second stage FC power generation portion 22, the third stage FC power generation portion 23
The fuel gas f _2, f ₃ and supplies the heats in the first stage fuel gas heating unit 61f and the second stage fuel gas heating 62f which was provided to the air Gokuhai gas line, is discharged from the first-stage FC power generation portion 20 The fuel electrode exhaust gas g ₁ and g ₂ are supplied.

As described above, the second-stage and third-stage FC power generation units 2
The fuel gas f _2, f ₃ is supplied to 2,23, although characterized by heating in the air electrode gas a _1, a _2, a second
The heating may also be performed by using as a cooling medium of the step heat exchange unit 92B. Further, the first stage heat exchanger 92A which is adapted to cool the recycled gas g _r by heating the fuel gas f ₁ may also be cooled by flowing condensate w that generates steam supplied to the steam turbine .

As described above, when the fuel gas f is individually mixed into the next-stage FC power generation section 20, the fuel electrode exhaust gas g
When the temperature decreases below a predetermined temperature, there is a disadvantage that it is necessary to balance (heat) the heat. However, in the present embodiment, the heat sources of the fuels f ₂ and f ₃ are changed to the air electrode exhaust gas a _1. ,
Since the a _2, the next stage FC anode exhaust gas g supplied to the power generation portion 20 is easily controlled to a predetermined temperature, the disadvantage described above can be eliminated. Further, by heating the fuel gas f ₁ in the first-stage heat exchanger 92A,
Similar to the sixth embodiment shown in FIG. 6, the inlet temperature of the inlet temperature of the first stage fuel gas heating unit 61f to supply temperature combustion gas f ₁ to the first stage power generation unit 21 supply increases,
The first-stage fuel heating section 61f can be reduced in size or can be omitted.

If the fuel gases f ₂ and f ₃ are used as a cooling medium for the second-stage heat exchanger 92B, the cooling caused by mixing the fuel gases f ₂ and f ₃ into the fuel electrode exhaust gas g can be reduced. It can be raised to a temperature that can be prevented.

Next, FIG. 9 is a block diagram showing a ninth embodiment of the combined cycle power plant of the present invention. As shown in the figure, the combined cycle power plant 18 of the present embodiment has two or more cooling FC power generation units 21A, 21B...
1B at the fuel electrode exhaust gas g and conditions the air electrode gas a separated from ..., the next stage cooling FC power generation portion 22B, and supplies a ..., exhaust a _n discharged from the last stage cooling FC power generation portion 20n, g _{n is} also separated from the combustor 420
To be supplied to

Further, from the first cooling stage FC power generation section 22a,
Air electrode exhaust gas a₁Discharged from compressor 460
The first-stage air heating section 61a and the fuel
Gas f supplied from the fuel supply unit 80₁Heating the first
A first-stage fuel gas heating unit 61f is provided, and a second cooling stage is provided.
Emitted from the cooling FC power generation unit after the FC power generation unit 22A
Air electrode exhaust gas a₁, A_Three…… to the next stage cooling FC power generation unit
Supplied fuel gas f _Two, F_ThreeFuel gas for heating…
The heating unit 60 was provided.

That is, by using the FC cooling injection method, the temperature of the air a and the fuel gas 9f injected into the cooling FC power generation units 21A, 21B.
And the cooling FC power generation unit 21
A, 21B... Air electrode exhaust gases a ₁ , a ₂
The fluid heating of the air a and the fuel gas 9f is performed in. It is to be noted that the fuel gas f is converted to the air electrode exhaust gas a ₁ , a ₂ .
The heating in the air exhaust gas a ₁ , a ₂
...... it is because a _n is discharged from the large amount of cooling FC power generation unit as compared to the fuel electrode exhaust gas g ₁ ...... g _n.

Thus, the air a and the fuel gas f are cooled F
Good finish temperature is low enough to supply to C power generation unit
Therefore, the heat utilization in the combined cycle power plant 18 is high,
For example, higher η due to increased steam turbine output_ccof
System. The fuel gas f₁Break
Injection of reforming steam into high-quality fuel gas is performed as shown in FIG.
Cathode exhaust gas a in the third embodiment of the invention₁, A_Two... a_nso
Steam produced by heating, first embodiment shown in FIG.
Generated in the gas turbine exhaust in the dry state,
Alternatively, the fifth to eighth embodiments shown in FIGS.
Discharged from fuel in the final stage FC power generation unit
Recycled gas g branched from pole exhaust gas _rWater vapor at
Any of the generated ones can be used.

[0116]

As described above, the combined cycle power plant of the present invention is a combined cycle power plant including an FC power generation unit, a GT power generation unit, and a steam turbine, in which a plurality of FC power generation units are arranged in series, Exhaust gas discharged from the fuel cell is supplied to a post-stage FC power generation unit to generate power.

As a result, all of the air supplied to the FC power generation section of each stage is supplied by one compressor.
The compression power per unit can be reduced, and the loss of compression power per output of the FC power generation unit can be reduced. Further, high-temperature supply of air / fuel gas to be supplied to the next-stage FC power generation unit, particularly high-temperature supply of air having a large supply flow rate, is facilitated, and FC exhaust is sent to the next-stage GT-HRSG-ST system at a high temperature. Power generation efficiency on the CC side of (GT + ST) can be improved. Further, the temperature of the exhaust gas supplied to the combustor from the final-stage FC power generation unit can be increased, and the amount of fuel for reburning the combustor at the gas turbine inlet temperature (predetermined temperature) can be reduced. Thus, the plant efficiency of the CC part (GT + ST) is 5 to 10% as compared with the conventional combined cycle power plant.
The above can be improved.

Further, the combined cycle power plant according to the present invention is interposed between the gas turbine and the GT exhaust heat recovery section,
A preheat regeneration unit that preheats air and fuel gas supplied to the C power generation unit with exhaust gas discharged from the gas turbine and discharges the preheated exhaust gas to a steam generation unit that generates steam for driving the steam turbine is a GT exhaust heat. Provided in the collection section.

As a result, only the first FC power generation unit in which a plurality of FC power generation units are arranged in series is heated by the preheating regeneration unit, particularly, the air supplied in a large amount. The capacity of the reaction gas heating unit that heats the air can be reduced, and the amount of fuel gas supplied for reheating by keeping the temperature of the exhaust gas supplied to the combustor high from the final stage FC power generation unit Can be further reduced, and the plant efficiency can be further improved.

Further, in the combined cycle power plant of the present invention, the air supplied from the air supply unit and the fuel supply unit to the first-stage FC power generation unit and the air supplied to the first-stage FC power generation unit or the FC power generation units in each stage are provided. A reaction gas heating unit for raising the temperature of the fuel gas to a required temperature was provided, and an FC power generation unit having three or more stages capable of performing preheating was provided, and the preheating regeneration unit was omitted.

As a result, the temperature of the exhaust gas supplied to the combustor from the final stage FC power generation unit can be increased, the amount of fuel gas supplied for reheating can be reduced, and the GT exhaust from the gas turbine can be reduced. The amount of steam that can be generated by the exhaust gas discharged to the heat recovery unit can be increased, and the amount of power generated by the steam turbine that is driven by the steam and outputs power can be increased, thereby further improving the power generation efficiency of the combined cycle power plant.

Further, the combined cycle power plant according to the present invention has an FC
At least the first-stage FC power generation unit of the power generation unit is a cooled FC power generation unit that can be operated with lower-temperature air and fuel gas than the conventional FC power generation unit.

As a result, the reaction gas supplied to the cooling FC power generation unit can be gradually reduced from 950 ° C. to 600 to 700 ° C.
The reaction gas heating section only needs to be provided with a first-stage air heating section for heating the air supplied from the compressor and a fuel gas heating section for heating the fuel gas supplied to the FC power generation section of the second and subsequent stages. The temperature of the exhaust gas supplied to the combustor from the stage FC power generation unit can be raised, the amount of fuel gas supplied for reburning the combustor can be reduced, and the reformed steam can be discharged from the pre-stage FC power generation unit. And the amount of steam that can be generated in the GT exhaust heat recovery unit can be increased, the amount of power generation of the steam turbine that is driven by steam and outputs power can be increased, and the power generation efficiency of the combined cycle power plant can be further improved.

The combined cycle power plant according to the present invention has
A plurality of power generation units including a power generation unit or a cooling FC power generation unit are arranged in series, and the fuel electrode exhaust gas and the air electrode exhaust gas discharged from the former power generation unit to the latter power generation unit are separately separated into the fuel electrode and the air electrode of the latter power generation unit And supplied to each of them to generate power.

As a result, the cathode exhaust gas discharged from the pre-stage power generation section to the cathode of the post-stage power generation section and the anode exhaust gas discharged from the pre-stage generation section to the fuel electrode of the post-stage generation section are maintained at high temperatures. Since the unreacted fuel gas discharged together with the exhaust gas is used in consideration of the use as the fuel gas of the post-stage power generation unit, the amount of fuel gas to be supplied to the post-stage power generation unit can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of a combined cycle power plant according to the present invention;

FIG. 2 is a block diagram showing a second embodiment of the combined cycle power plant according to the present invention;

FIG. 3 is a block diagram showing a third embodiment of the combined cycle power plant according to the present invention;

FIG. 4 is a block diagram showing a fourth embodiment of the combined cycle power plant according to the present invention;

FIG. 5 is a block diagram showing a fifth embodiment of the combined cycle power plant according to the present invention;

FIG. 6 is a block diagram showing a sixth embodiment of the combined cycle power plant according to the present invention;

FIG. 7 is a block diagram showing a seventh embodiment of the combined cycle power plant according to the present invention;

FIG. 8 is a block diagram showing an eighth embodiment of the combined cycle power plant according to the present invention;

FIG. 9 is a block diagram showing a ninth embodiment of the combined cycle power plant according to the present invention;

FIG. 10 is a block diagram showing an example of a conventional combined cycle power plant.

[Explanation of symbols]

10, 11, 12, 13, 14, 15, 16, 17, 1
8 Combined cycle power plant 20 FC power generation unit 21 First stage FC power generation unit 21A Cooling first stage FC
Power generation unit 22 Second stage FC power generation unit 22A Cooling second stage FC
Power generation unit 23 Third stage FC power generation unit 24 Reactive gas heat exchange unit 30, 30A Combustion unit 31 First stage combustion unit 32 Second stage combustion unit 33 Third stage combustion unit 40 GT power generation unit 50 Preheating regeneration unit 60 Reactive gas heating parts 61 and 61a, 61b first stage reaction gas heating unit 62, 62a, 62b second stage reaction gas heating unit 63 the third stage reaction gas heating unit 70 GT exhaust heat recovery unit 71,71f _1, 71f _2, 71f ₃ Kai Steam generator 72 steam generator 80 fuel gas supply unit 90 recycling circulation unit 91 recycling circulation fan 92 heat exchange unit 92A first stage heat exchanger 92B second stage heat exchanger a air f fuel gas g exhaust gas s steam a _1, a _2, a ₃ air electrode gas g _1, g _2, g ₃ anode exhaust gas 100 FC power generation unit 200 a combustion section 300 reactive gas heating unit 320 the fuel gas heating unit 340 the air heating unit 400 GT power generation unit 420 Combustor 440 Gas turbine 460 Air compressor 480 Generator 500 GT exhaust heat recovery unit 520 Air preheat regenerator 540 Fuel gas preheat regenerator 560 Steam generator 580 Chimney 600 Fuel gas supply unit 700 Air supply unit 1000 Combined power plant

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01M 8/04 H01M 8/04 J

Claims (5)

[Claims] 1. An FC power generation unit for generating power by performing an electrochemical reaction between air and a fuel gas via an electrolyte, and driving a high temperature by burning an air electrode exhaust gas and a fuel electrode exhaust gas discharged from the FC power generation unit. A GT power generation unit comprising a gas turbine having a combustor for generating gas, a compressor for compressing supplied air into air to be supplied to the air electrode, and a generator for operating a generator for outputting electric power by the driving gas. And a steam turbine that is driven by steam generated by exhaust gas discharged from the gas turbine to the GT exhaust heat recovery section and outputs electric power.
A combined power plant in which a plurality of C power generation units are arranged in series, and exhaust gas discharged from a front-stage FC power generation unit is supplied to a rear-stage FC power generation unit to generate power. 2. The method according to claim 1, wherein the air and fuel gas supplied to the first-stage FC power generation unit are interposed between the gas turbine and the GT exhaust heat recovery unit and preheated by the exhaust gas discharged from the gas turbine. 2. The combined cycle power plant according to claim 1, further comprising a preheating regeneration section for discharging the exhaust gas after preheating to the GT exhaust heat recovery section. 3. An air supply unit and a fuel supply unit, wherein
The number of stages of FC power generation units provided to the stage FC power generation unit, which can heat the air and fuel gas to a required temperature, is provided.
2. The combined cycle power plant according to claim 1, wherein a preheating regeneration section provided in the T exhaust heat recovery section is omitted. 4. At least a first of the FC power generation units
2. The combined cycle power plant according to claim 1, wherein the stage FC power generation unit is a cooled FC power generation unit that operates with the air and the fuel gas at a lower temperature than the conventional FC power generation unit. 5. The fuel cell system according to claim 1, wherein a plurality of FC power generation units are arranged in series, and the fuel electrode exhaust gas and the air electrode exhaust gas discharged from the pre-stage FC power generation unit to the post-stage FC power generation unit are separately supplied to the post-stage FC power generation unit. Respectively supplied to the fuel electrode and the air electrode,
The combined cycle power plant according to claim 1, wherein power is generated.