JP2006090287A - Composite power generation system and fuel gas calorific value control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize stable power generation by keeping a calorific value of fuel gas at an inlet of a combustor of a gas turbine at a fixed value irrespective of a reaction condition in fuel cell facility and fluctuation of load over the whole composite power generation system. <P>SOLUTION: This composite power generation system is provided with the fuel cell facility 1, gas turbine facility 2 for supplying fuel gas outputted from the fuel cell facility 1 to the combustor 21 through a fuel gas flow passage 4, a flammable gas bypass flow passage G3 for supplying flammable gas purified in the system into the fuel gas flow passage G4, and a controller 50 for controlling amount of flammable gas supplied from the flammable gas bypass flow passage G3 to keep a calorific value at the inlet of the combustor 21 of the gas turbine 22 at the fixed value. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a combined power generation system including a fuel cell facility.

In recent years, an integrated gasification combined cycle (IGCC) that combines fuel cell equipment with gas turbine equipment, steam turbine equipment, etc. has attracted attention in terms of its high power generation efficiency and environmental compatibility. Development and research are underway.
As such an IGCC, for example, Japanese Patent Application Laid-Open No. 2003-36872 (Patent Document 1) discloses a combined power generation system capable of configuring a combined power generation with a fuel cell by using an existing power generation plant as it is. It is disclosed.
Japanese Patent Laying-Open No. 2003-36872 (FIG. 1)

  As shown in Patent Document 1, generally, in an IGCC incorporating a fuel cell facility, the fuel cell facility is installed on the upstream side of the fuel gas flow path of the gas turbine facility or the steam turbine facility. The unreacted fuel gas, unreacted air, and the like output from the fuel cell facility are supplied to a gas turbine facility installed on the downstream side, where they are burned. Thus, in IGCC incorporating a fuel cell facility, it is possible to obtain high power generation efficiency by effectively using fuel gas without leaving it.

By the way, in the IGCC having such a configuration, when a load fluctuation is given to the entire system, a disturbance that generates a heat generation fluctuation of the fuel gas at the combustor inlet of the gas turbine is generated, and stable power generation is performed in the gas turbine equipment. There was a problem that the amount could not be obtained.
In addition, the calorific value of the fuel gas supplied to the gas turbine depends not only on the upstream gasifier operating state but also on the power generation (reaction) state of the fuel cell. There is a risk of disturbance to the operation, and there is a problem that the stability of power generation by the gas turbine is hindered.

  The present invention has been made in view of such circumstances, and a combined power generation system and a fuel gas heating value control method capable of realizing stable power generation by keeping the heating value of fuel gas at a combustor inlet of a gas turbine constant. The purpose is to provide.

In order to solve the above problems, the present invention employs the following means.
A combined power generation system comprising a fuel cell facility or a fuel co-production device, and a gas turbine in which fuel gas output from the fuel cell facility or the fuel co-production device is supplied to the combustor via a fuel gas flow path The combustible gas supply means for supplying the combustible gas purified in the system to the fuel gas flow path, and the combustible gas so as to make the calorific value at the combustor inlet of the gas turbine constant. There is provided a combined power generation system comprising control means for controlling the amount of combustible gas supplied from a property gas supply means.

The fuel gas after the reaction of the fuel cell is guided to the combustor of the gas turbine via the fuel gas flow path. At this time, for example, if the reaction amount in the fuel cell is large, the calorie of the fuel gas output from the fuel cell is relatively low, and the calorific value supplied to the fuel device of the gas turbine is low.
According to the present invention, even if the fuel gas calorie output from the fuel cell decreases, the combustible gas supply means supplies the combustible gas to the fuel gas flow path, so the gas of the fuel gas output from the fuel cell. It becomes possible to increase calories. Thereby, the emitted-heat amount in the combustor inlet of a gas turbine can be kept constant.
The combustible gas supply means supplies the combustible gas purified within the system, not from the outside, so that it can be operated as one independent system.
The fuel co-production device is, for example, a device that extracts methane.
The combustible gas has a higher gas calorie than that of the fuel gas output from the fuel cell.

In the combined power generation system of the present invention, the combustible gas supply means is a fuel gas output from a desulfurization facility or a dust removal facility that purifies the fuel gas supplied to the fuel cell facility or the fuel co-production device. It is preferable to supply the portion to the fuel gas flow path.
In particular, if a part of the fuel gas output from the dedusting device provided upstream of the desulfurization equipment is supplied to the fuel gas flow path in the fuel gas flow path, the amount of gas processed in the desulfurization equipment is reduced. The cost can be reduced by reducing the number of catalysts used for desulfurization.

  The present invention includes a fuel cell facility or a fuel co-production device, and a gas turbine in which fuel gas output from the fuel cell facility or the fuel co-production device is supplied to the combustor via a fuel gas flow path. A combined power generation system comprising a nitrogen gas supply means for supplying nitrogen gas purified in the system to the fuel gas flow path, and a calorific value at a combustor inlet of the gas turbine, There is provided a combined power generation system comprising control means for controlling the amount of nitrogen gas supplied from the nitrogen gas supply means.

The fuel gas after the reaction of the fuel cell is guided to the combustor of the gas turbine via the fuel gas flow path. At this time, if the reaction amount in the fuel cell is small, the calorie of the fuel gas output from the fuel cell becomes relatively high, and the heat generation amount in the fuel device of the gas turbine increases.
According to the present invention, even if the fuel gas calorie output from the fuel cell rises, the nitrogen gas supply means supplies the nitrogen gas to the fuel gas flow path, so the gas calorie of the fuel gas output from the fuel cell can be reduced. It can be reduced. Thereby, the emitted-heat amount in the combustor inlet of a gas turbine can be kept constant.

In such a combined power generation system, it is preferable that the nitrogen gas supply means supplies a part of the nitrogen gas supplied to the fuel cell facility or the fuel co-production device to the fuel gas flow path.
For example, the nitrogen gas supply means supplies nitrogen gas output from an air separation facility that separates oxygen and nitrogen from air to the fuel gas flow path.

  The present invention includes a fuel cell facility or a fuel co-production device, and a gas turbine in which fuel gas output from the fuel cell facility or the fuel co-production device is supplied to the combustor via a fuel gas flow path. A combined power generation system comprising: a combustible gas supply means for supplying a combustible gas purified in the system to the fuel gas flow path; and a nitrogen gas purified in the system in the fuel gas flow. Nitrogen gas supply means for supplying to the road, and the amount of combustible gas supplied from the combustible gas supply means and the nitrogen gas supply means so as to make the calorific value in the combustor of the gas turbine constant. And a control means for controlling the amount of nitrogen gas.

According to the present invention, the apparatus includes the combustible gas supply means for supplying the combustible gas to the fuel gas output from the fuel cell, and the nitrogen gas supply means for supplying the nitrogen gas to the fuel gas output from the fuel cell. The combustible gas or nitrogen gas can be mixed with the fuel gas output from the fuel cell according to the increase or decrease of the reaction amount by the fuel cell.
Thereby, the gas calorie of the fuel gas supplied to the combustor of the gas turbine can be kept constant, and the calorific value in the combustor can be made constant.

In such a combined power generation system, the combustible gas supply means and the nitrogen gas supply means are preferably connected to the fuel gas flow path via a three-way valve.
Thus, since the combustible gas supply means and the fuel gas flow path are connected to the fuel gas pipe by the three-way valve, the fuel gas is output from the fuel cell according to the gas calorie of the fuel gas output from the fuel cell. It becomes possible to continuously mix the combustible gas or the nitrogen gas with the fuel gas.
For example, when the gas calorie of the fuel gas output from the fuel cell is high, nitrogen gas is supplied to the fuel gas flow path by closing the valve on the combustible gas supply side and opening the valve on the nitrogen gas supply side. The three-way valve is controlled as follows. Then, as the gas calorie gradually decreases, the nitrogen gas supply amount is gradually reduced by gradually narrowing the valve on the nitrogen gas supply side. When the gas calorie of the fuel gas output from the fuel cell is lower than the lower limit value, the combustible gas is supplied to the fuel by closing the valve on the nitrogen gas supply side and opening the valve on the combustible gas supply side. The three-way valve is controlled so as to be supplied to the gas flow path. And it is controlled so that the opening degree of the valve on the combustible gas supply side becomes larger as the gas calorie becomes lower.

In the above combined power generation system, the control means is configured to reduce the supply amount of the combustible gas and the nitrogen gas based on a value obtained by subtracting an actual heat generation amount at the combustor inlet from a target heat generation amount at the combustor inlet of the gas turbine. Is preferably determined, and the opening of the three-way valve is adjusted according to the supply amount.
Further, it is preferable that the control means reflects the amount of power generation in the fuel cell facility as a disturbance in the calculation process of the supply amount of the combustible gas and the supply amount of the nitrogen gas.
Considering the power generation amount of the fuel cell facility as a disturbance, the supply amount of the combustible gas and the supply amount of the nitrogen gas are determined, so that the control accuracy can be further improved.

The present invention includes a fuel cell facility or a fuel co-production device, and a gas turbine in which fuel gas output from the fuel cell facility or the fuel co-production device is supplied to the combustor via a fuel gas flow path. A method for controlling a fuel gas calorific value of a combined power generation system comprising: a combustible gas purified in the combined power generation system and / or the composite so as to make a calorific value at a combustor inlet of the gas turbine constant. Provided is a fuel gas heating value control method for supplying purified nitrogen gas in a power generation system to the fuel gas flow path.
Since the combustible gas and / or nitrogen gas is mixed with the fuel gas output from the fuel cell, the heat generation amount at the combustor inlet of the gas turbine can be kept constant.

  According to the combined power generation system and the fuel gas heat generation amount control method of the present invention, the heat generation amount of the fuel gas at the inlet of the combustor of the gas turbine can be kept constant, so that stable power generation can be realized.

  Hereinafter, an embodiment of a combined power generation system of the present invention will be described in detail in the order of [First Embodiment], [Second Embodiment], and [Third Embodiment] with reference to the drawings.

[First Embodiment]
FIG. 1 is a diagram showing an overall configuration of a combined power generation system according to the first embodiment of the present invention.
As shown in FIG. 1, the combined power generation system according to the present embodiment is configured as a triple combined type combined power generation system including a fuel cell facility 1, a gas turbine facility 2, and a steam turbine facility 3. This combined power generation system includes a fuel supply facility 4, an air separation facility 5, a gasification furnace 6, a dust removal facility 7, a desulfurization facility 8, a waste heat recovery boiler facility 9, and the like as peripheral facilities.

In the combined power generation system configured as described above, the gasification furnace 6 reacts the gasified fuel supplied from the fuel supply facility 4 with the oxygen gas that is the oxidant supplied from the air separation facility 5, and is combustible. A high-temperature crude gas containing CO and H ₂ that are sexual gases is generated.
In this case, the gasified fuel and the oxygen gas are respectively adjusted to appropriate amounts by flow rate control valves (not shown) provided in the gasified fuel flow path G1 and the oxygen gas flow path Q1, and supplied to the gasification furnace 6. The
The crude gas generated in the gasification furnace 6 is supplied to the dust removal equipment 7 via the gas cooler 10. The dust removal equipment 7 is composed of a scrubber or the like, and removes fine particles such as ash contained in the crude gas.
The crude gas processed in the dedusting facility 7 is supplied to the desulfurization facility 8. The desulfurization facility 8 desulfurizes sulfur from the crude gas treated in the dust removal facility 7 to generate fuel gas. The fuel gas generated in the desulfurization facility 8 is supplied to the fuel cell facility 1 via the fuel gas flow path G2, and via the combustible gas bypass flow path (flammable gas supply means) G3, It is guided to the subsequent gas flow path G4.

The fuel cell facility 1 is a solid oxide fuel cell (hereinafter referred to as “SOFC (Solid Oxide Fuel)”.
Cell) ". ) 11, a fuel regeneration heat exchanger 12, and an air regeneration heat exchanger 13.
The fuel regeneration heat exchanger 12 supplies the fuel gas supplied from the desulfurization facility 8 to the SOFC 11, collects unreacted fuel gas in the SOFC 11, outputs it to the fuel gas flow path G 4, and further generates heat in the SOFC 11. The heat of the unreacted fuel gas that has become a high temperature due to the reaction is given to the fuel gas supplied from the desulfurization facility 8 to fulfill the function of adjusting the power generation (reaction) conditions in the SOFC 11. The unreacted fuel gas that has exited the fuel regeneration heat exchanger 12 is reused in the gas turbine facility 2 described later.
The air regeneration heat exchanger 13 supplies air supplied from an air flow path Q2 described later to the SOFC 11, collects unreacted air in the SOFC 11, outputs it to the air flow path Q3, and further generates an exothermic reaction in the SOFC 11. Thus, the heat of the unreacted air that has reached a high temperature is given to the air supplied from the air flow path Q2, and the power generation (reaction) conditions in the SOFC 11 are adjusted. The unreacted air that has exited the air regeneration heat exchanger 13 is reused in the gas turbine equipment 2 described later.
The SOFC 11 generates electricity by causing an electrochemical reaction between the fuel gas supplied from the fuel regeneration heat exchanger 12 and the high-temperature air supplied from the air regeneration heat exchanger 13.

A flammable gas bypass passage G3 as a flammable gas supply means is connected to the fuel gas passage G4 for supplying unreacted fuel gas from the fuel regeneration heat exchanger 12 to the gas turbine equipment 2. This combustible gas bypass flow path G3 is for supplying the high-calorie combustible gas output from the desulfurization facility 8 directly to the fuel gas flow path G4.
In the vicinity of the connection point between the combustible gas bypass flow path G3 and the fuel gas flow path G4, the fuel gas after the reaction by the SOFC 11 and the high calorie combustible gas output from the desulfurization facility 8 are mixed and mixed. Fuel gas (hereinafter referred to as “mixed fuel gas”) is supplied to a combustor 21 of a gas turbine facility 2 described later.
In this case, the combustible gas bypass channel G3 is provided with a flow rate adjusting valve 100 for controlling the flow rate of the fuel gas supplied to the fuel gas channel G4. The opening degree of the flow control valve 100 is controlled by a control device 50 described later, and the gas calorie of the mixed fuel gas is kept constant.

  A governor 14 as a fuel gas flow control valve is provided on the downstream side (gas turbine equipment side) of the connection point between the fuel gas passage G4 and the combustible gas bypass passage G3. By adjusting the opening of the governor 14, the pressure or flow rate of the mixed fuel gas sent to the gas turbine equipment 2 is controlled.

The gas turbine facility 2 includes a combustor 21 that combusts gasified fuel, a gas turbine 22 that rotates by expanding the combustion gas supplied from the combustor 21, and a compressor 23 that compresses air.
The combustor 21 burns the mixed fuel gas supplied from the fuel gas flow path G4 using the air supplied from the air flow path Q3, and supplies the generated high-temperature and high-pressure combustion gas to the gas turbine 22.
The gas turbine 22 rotates with the energy generated when the combustion gas expands, and the power is transmitted to the generator 40 to generate electric power.
The exhaust gas discharged from the gas turbine facility 2 is guided to the exhaust heat recovery boiler facility 9, where the feed water is heated to generate steam, and is discharged from the chimney to the atmosphere.
On the other hand, the steam generated from the exhaust heat recovery boiler facility 9 drives each steam turbine 31 in the steam turbine facility 3 and drives the generator 40 by this rotational force.
In addition, in the said structure, although the gas turbine 22, the steam turbine 31, and the generator 40 are comprised coaxially (one axis | shaft), it may be comprised not only in this but in multiple axes.

The steam generated in the steam turbine equipment 3 works in the steam turbine 31, is then condensed into saturated water by the condenser 32 in the condensate supply equipment, and is pressurized by the feed water pump to the exhaust heat recovery boiler equipment 9. Supplied and reused.
The air separation facility 5 separates air into oxygen and nitrogen to produce high concentration oxygen. Oxygen produced by the air separation facility 5 is supplied to the gasification furnace 3 through the oxygen gas flow path Q1. In this case, the oxygen gas flow path Q1 is provided with a flow rate adjusting valve (not shown) for adjusting the flow rate of oxygen.

Next, a control system of the combined power generation system configured as described above will be described.
First, output control of the generator 40 and pressure control of fuel gas supplied to the gas turbine equipment 2 will be described.
Here, the output control of the generator 40 is performed by controlling the opening degree of the governor 14 provided in the fuel gas flow path G4. On the other hand, the pressure control of the fuel gas is performed by adjusting a flow rate adjusting valve (not shown) for adjusting the flow rate of the gasified fuel supplied to the gasification furnace 3 and the flow rate of oxygen and air supplied to the gasification furnace 3. This is performed by controlling the opening degree of a flow control valve (not shown).

FIG. 2 is a block diagram illustrating an example of the configuration of the power generation control unit 60 that performs output control of the generator 40 and the pressure control unit 70 that performs pressure control of the fuel gas.
As shown in FIG. 2, the power generation control unit 60 subtracts the power generation amount by the power generation facility other than the gas turbine facility 2 from the generator output command MWD that is the target power generation amount of the entire combined power generation system. The gas turbine output command calculation unit 61 that calculates the output command of the gas turbine, and the governor opening command calculation unit 62 that converts the output command obtained by the gas turbine output command calculation unit 61 into the opening command of the governor 14 (see FIG. 1). And.

The gas turbine output command calculation unit 61 obtains the generator output command MWD and the actual power generation amount of the fuel cell facility 1 as input information, and calculates a difference between the first subtracter 63 and the first subtraction. And a second subtractor 64 that obtains the output of the generator 63 and the actual power generation amount of the steam turbine as input information and calculates a difference between them.
The gas turbine output command calculated by the gas turbine output command calculation unit 61 having such a configuration is given to the governor opening command calculation unit 62. Then, the governor opening command calculation unit 62 calculates the opening command of the governor 14 (see FIG. 1) based on the gas turbine output command. Then, by actually controlling the opening degree of the governor 14 based on this opening degree command, the power generation amount of the gas turbine equipment 2 can be brought close to the gas turbine output command, and the power generation as the entire combined power generation system Control that brings the amount close to the generator output command MWD can be realized.

  When the steam turbine equipment 3 is configured with a single shaft, the power generation amount of the steam turbine 31 is estimated by multiplying the steam flow rate and the steam temperature, and the estimated power generation amount is used as the power generation of the steam turbine 31. The amount may be input to the second subtractor 62.

Next, the pressure control unit 70 is input with a generator output command MWD that is a target power generation amount of the entire combined power generation system, and the first calculator 71 that calculates the gasifier input command GID based on the generator output command MWD. The generator output command MWD is input, and based on this, the second calculator 72 that calculates the gas pressure setting, the gas pressure setting that is the output of the second calculator 72, and the actual gas pressure of the fuel gas are obtained. These are the subtractor 73 that is obtained as input information, calculates the difference between them, the controller 74 that calculates an appropriate GID correction amount by PI or PID control of the output of the subtractor 73, and the output of the controller 74. An adder 75 that adds the GID correction amount and the output of the first calculator 71 to calculate a final gasifier input command GID is provided.
The final gasifier input command GID output from the adder 75 is input to the third calculator 76, the fourth calculator 77, and the fifth calculator 78. Based on the gasifier input command GID, the third calculator 76 opens an opening for controlling the opening of a flow rate control valve (not shown) provided in the gasification fuel flow path G1 (see FIG. 1). Calculate the degree command. Based on this gasifier input command GID, the fourth arithmetic unit 77 controls the opening degree of the flow rate control valve (not shown) provided in the oxygen gas flow path Q1 (see FIG. 1). Calculate the command. The fifth computing unit 78 is based on the gasifier input command GID, and an opening degree command for controlling the opening degree of a flow rate control valve (not shown) provided in the air supply path Q5 (see FIG. 1). Is calculated.

  As shown in FIG. 1, the opening degree of the flow rate control valve (not shown) provided in the gasification fuel flow path G1 for supplying gasification fuel from the fuel supply facility 4 to the gasification furnace 3 is the third calculation. The opening degree of a flow rate control valve (not shown) provided in the oxygen gas flow path Q1 that is controlled according to the opening degree command calculated by the vessel 76 and supplies oxygen gas from the air separation facility 5 to the gasification furnace 3 is determined. Control is performed based on the opening degree command calculated by the fourth arithmetic unit 77. Further, the degree of opening of a flow control valve (not shown) provided in the air supply path Q5 is the air extracted from the gas turbine air compressor and increased by the compressor. By controlling according to the degree command, the gasified fuel, oxygen gas, and air supplied to the gasification furnace 3 are adjusted to appropriate amounts. As a result, the gas pressure at the inlet of the combustor 21 of the gas turbine equipment 2 can be stabilized.

Next, the flow control of the combustible gas supplied from the combustible gas bypass channel G3 shown in FIG. 1 to the fuel gas channel G4 will be described with reference to FIG.
The flow control of the combustible gas is performed by controlling the opening degree of the flow control valve 100 provided in the combustible gas bypass flow path G3.
FIG. 3 is a block diagram showing an example of the configuration of a control device (control means) 50 that controls the flow rate of the combustible gas.
As shown in FIG. 3, the control device 50 includes an analog memory 51 in which a target heat generation amount at the inlet of the combustor 21 of the gas turbine is set in advance, a target heat generation amount that is an output of the analog memory 51, and an actual heat generation amount. Is obtained as input information, and a subtractor 52 that calculates these differences and a controller 53 that calculates an opening degree command of the flow rate control valve 100 from the output of the subtractor 52 are provided.
According to such a configuration, the subtractor 52 subtracts the actual heat generation amount from the target heat generation amount, thereby obtaining a difference, and the controller 53 calculates the opening degree command of the flow rate control valve 100 based on this difference. Is done. Then, by controlling the opening degree of the flow rate control valve 100 based on this opening degree command, it becomes possible to bring the heat generation amount at the inlet of the combustor 21 close to the target heat generation amount, and to keep the heat generation amount constant. It becomes possible.

Next, the control device 50 having the above-described configuration can also be configured by a block diagram as shown in FIG. 4 or FIG.
FIG. 4 is a block diagram showing a configuration of the control device 50 in a first modification, and FIG. 5 is a block diagram showing a configuration of the control device 50 in a second modification. In these drawings, the same components as those in FIG. 3 are denoted by the same reference numerals, and description thereof is omitted.
The control device 50 according to the first modification shown in FIG. 4 includes a calculator 54 that calculates a target heat generation amount based on a generator output command MWD that is a target power generation amount of the entire combined power generation system. The feedback control is performed so that the actual heat generation amount approaches the target heat generation amount calculated by 54.
Thus, by calculating the target heat generation amount by the calculator 54, the target heat generation amount can be set to a more appropriate value.

The control device 50 according to the second modification shown in FIG. 5 considers the power generation amount of the fuel cell facility 1 as a disturbance, and calculates the opening degree command of the flow rate control valve 100 in a form reflecting this disturbance. It is what I did.
Specifically, a disturbance calculation unit 80 that calculates a disturbance is provided, and the disturbance obtained by the disturbance calculation unit 80 is an opening command (hereinafter referred to as a “primary opening command”) that is an output of the controller 53. To determine the final opening command.
The disturbance calculation unit 80 includes, for example, a calculator 81 that calculates a target power generation amount by the SOFC 11 (see FIG. 1) based on a generator output command MWD that is a target power generation amount of the entire combined power generation system, and a calculator 81. A subtractor 82 that subtracts the actual power generation amount of SOFC 11 from the obtained target power generation amount of SOFC 11 and a compensation calculator 83 that calculates a correction amount according to the SOFC output deviation that is the output of subtractor 82 are provided. .
The disturbance obtained by the compensation calculation unit 83 of the disturbance calculation unit 80 is input to the adder 55, where it is added to the primary opening degree command obtained by the controller 53, and the final opening degree instruction is obtained. Calculated.
Then, the amount of heat generated at the inlet of the combustor 21 can be made closer to the target amount of heat by controlling the degree of opening of the flow rate control valve 100 based on the final degree of opening command that is the output of the adder 55. It becomes possible, and it becomes possible to keep calorific value constant.

As described above, according to the combined power generation system according to the present embodiment, the combustible gas bypass flow path G3 for supplying the combustible gas purified in the system to the fuel gas flow path G4, Since the controller 50 for controlling the flow rate of the combustible gas supplied to the fuel gas flow path G4 so as to make the heat generation amount at the inlet of the combustor 21 of the gas turbine 22 constant, the reaction amount in the SOFC 11 is large, Even if the calorie of the fuel gas output from the SOFC 11 is relatively low, the fuel gas output from the SOFC 11 is supplied by supplying the combustible gas from the combustible gas bypass channel G3 to the fuel gas channel G4. It becomes possible to increase gas calories.
Thereby, the calorific value at the inlet of the combustor 21 of the gas turbine 22 can be kept constant. As a result, power generation in the gas turbine facility 2 can be stabilized, and a stable power generation amount can be obtained as the combined power generation system as a whole.
Further, since the combustible gas supplied to the fuel gas flow path G4 by the combustible gas bypass flow path G3 is purified in the combined power generation system, a full integration type independent power generation system is constructed. be able to.

  In the combined power generation system according to the present embodiment, the fuel gas output from the desulfurization facility 8 is supplied as the combustible gas supplied to the fuel gas passage G4. However, the present invention is not limited to this example. The fuel gas output from the dust removing device 7 may be partially supplied to the fuel gas flow path G4. According to such a configuration, since the amount of gas processed in the desulfurization facility 8 can be reduced, it is possible to reduce costs by reducing the number of catalysts used for desulfurization.

[Second Embodiment]
Next, a combined power generation system according to a second embodiment of the present invention will be described with reference to the drawings.
FIG. 6 is a diagram showing an overall configuration of the combined power generation system according to the second embodiment of the present invention. In this figure, the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.
The difference between the combined power generation system of the present embodiment and the combined power generation system according to the first embodiment is that instead of the flammable gas bypass flow path G3 that supplies the flammable gas from the desulfurization facility 8 to the fuel gas flow path G4, A nitrogen gas bypass channel (nitrogen gas supply means) Q4 for supplying nitrogen gas from the air separation facility 5 to the fuel gas channel G4 is provided.
The nitrogen gas bypass channel Q4 is provided with a flow rate adjustment valve 101 for adjusting the flow rate of nitrogen gas. The flow control valve 101 is controlled in its opening degree by a control device (control means) 90. The control device 90 adjusts the flow rate of nitrogen gas supplied to the fuel gas flow path G4 by controlling the opening degree of the flow rate control valve 101 so that the amount of heat generated at the inlet of the combustor 22 is constant.

The configuration of the control device 90 can be almost the same as that of the first embodiment shown in FIGS. 3 to 5, and the operation of the controller 53 is supplied with nitrogen gas from the output of the subtractor 52. What is necessary is just to set it as the structure which calculates the opening degree instruction | command in the case of doing.
For example, a map for obtaining an opening degree command by changing the arithmetic expression or using the output of the subtractor 52 as one of the parameters is provided, and the opening degree command is obtained based on this map. If control is being performed, the map to be used may be changed to a map for supplying nitrogen gas.

  Thus, in the combined power generation system according to the first embodiment, the amount of heat generated at the inlet of the combustor 21 is increased by mixing the combustible gas with the fuel gas output from the SOFC 11 and increasing the concentration of the fuel gas. In the combined power generation system according to this embodiment, the fuel gas output from the SOFC 11 is mixed with nitrogen gas to dilute the fuel gas and reduce its concentration. The heat generation amount at the inlet of the combustor 21 is stabilized.

As described above, according to the combined power generation system according to the present embodiment, the nitrogen gas bypass channel Q4 for supplying the nitrogen gas purified in the system to the fuel gas channel G4, and the gas turbine And a control device 90 for controlling the flow rate of nitrogen gas supplied from the nitrogen gas bypass flow path Q4 to the fuel gas flow path G4 so as to make the heat generation amount at the inlet of the 22 combustors 21 constant, the reaction in the SOFC 11 Even if the amount is low and the calorie of the fuel gas output from the SOFC 11 is relatively high, the gas calorie of the fuel gas output from the SOFC 11 is reduced by supplying nitrogen gas to the fuel gas channel G4. It becomes possible to make it.
Thereby, the calorific value at the inlet of the combustor 21 of the gas turbine 22 can be kept constant. As a result, it is possible to stabilize the power generation in the gas turbine facility, and the combined power generation system as a whole can obtain a stable power generation amount.

[Third Embodiment]
Next, a combined power generation system according to a third embodiment of the present invention will be described with reference to the drawings.
FIG. 7 is a schematic diagram showing the overall configuration of the combined power generation system according to the third embodiment of the present invention. In this figure, components common to the first and second embodiments are denoted by the same reference numerals and description thereof is omitted.

The combined power generation system of the present embodiment has a configuration having both the characteristics of the combined power generation system according to the first embodiment and the characteristics of the combined power generation system according to the second embodiment.
That is, the combined power generation system according to the present embodiment includes a combustible gas bypass channel (combustible gas supply means) G3 that supplies a combustible gas that is an output of the desulfurization facility 8 to the fuel gas channel G4, and an air separation facility. And a nitrogen gas bypass passage (nitrogen gas supply means) Q4 for supplying the nitrogen gas output from the fuel gas passage G4 to the fuel gas passage G4.
The combustible gas bypass channel G3 and the nitrogen gas bypass channel Q4 are connected to the fuel gas channel G4 via the three-way valve 200. The opening degree of the three-way valve 200 is controlled by a control device (control means) 120.
The control device 120 controls the opening degree of the three-way valve 200 so that the amount of heat generated at the inlet of the combustor 22 of the gas turbine 21 is constant, and the flow rates of combustible gas and nitrogen gas supplied to the fuel gas flow path G4. Adjust.

About the structure of this control apparatus 120, it can take the structure substantially the same as 1st Embodiment shown in FIGS. 3-5, and the operation | movement of the controller 53 is made into the combined power generation system which concerns on this embodiment. You can make it suitable.
For example, as shown in FIG. 8, when the gas calorie of the fuel gas output from the SOFC 11 is high (in FIG. 8, when the control command value for the calorific value on the horizontal axis is low), the combustible gas supply side valve Is closed and the valve on the nitrogen gas supply side is opened, so that the three-way valve 200 is controlled so that nitrogen gas is supplied to the fuel gas flow path G4.
Then, as the gas calorie gradually decreases, in other words, in FIG. 8, as the calorific value control command value on the horizontal axis gradually increases, the nitrogen gas supply side valve is gradually throttled, thereby supplying nitrogen gas. Reduce the amount gradually. When the gas calorie of the fuel gas output from the SOFC 11 is equal to or lower than a preset lower limit value, in other words, in FIG. 8, when the heat generation amount control command value becomes the value X. The three-way valve 200 is controlled so that the combustible gas is supplied to the fuel gas flow path G4 by closing the valve on the nitrogen gas supply side and opening the valve on the combustible gas supply side. And it is controlled so that the opening degree of the valve on the combustible gas supply side becomes larger as the gas calorie becomes lower.

As described above, according to the combined power generation system according to the present embodiment, the combustible gas bypass flow path G3 for supplying the combustible gas purified in the system to the fuel gas flow path G4, The above combustible so that the calorific value at the inlet of the combustor 21 of the gas turbine 22 and the nitrogen gas bypass channel Q4 for supplying the nitrogen gas purified in the system to the fuel gas channel G4 is constant. Since the control device 120 that controls the flow rate of the volatile gas and the flow rate of the nitrogen gas is provided, the flammable gas or the nitrogen gas can be mixed with the fuel gas output from the SOFC 11 in accordance with the increase or decrease of the reaction amount by the SOFC 11. It becomes possible.
Thereby, the gas calorie of the fuel gas supplied to the combustor 21 of the gas turbine 22 can be kept constant, and the calorific value in the combustor 22 can be made constant.
As a result, it is possible to stabilize the power generation in the gas turbine equipment 2, and the combined power generation system as a whole can obtain a stable power generation amount.

As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the specific structure is not restricted to this embodiment, The design change etc. of the range which does not deviate from the summary of this invention are included.
For example, the same effect can be obtained even if a fuel co-production device is employed instead of the fuel cell facility 1 in FIGS. 1, 6, and 7. The fuel co-production device is a device that collects methane gas, for example.

1 is a diagram illustrating an overall configuration of a combined power generation system according to a first embodiment of the present invention. It is the block diagram which showed an example of the structure of the power generation control part which performs output control of the generator shown in FIG. 1, and the pressure control part which performs pressure control of fuel gas. It is the block diagram which showed an example of the structure of the control apparatus shown in FIG. It is a block diagram which shows the structure which concerns on the 1st modification of the control apparatus shown in FIG. It is a block diagram which shows the structure which concerns on the 2nd modification of the control apparatus shown in FIG. It is a figure which shows the whole structure of the combined power generation system which concerns on the 2nd this embodiment of this invention. It is a figure which shows the whole structure of the combined power generation system which concerns on the 3rd this embodiment of this invention. It is a figure for demonstrating the opening degree control of the three-way valve shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel cell equipment 2 Gas turbine equipment 3 Steam turbine equipment 5 Air separation equipment 6 Gasification furnace 7 Dedusting equipment 8 Desulfurization equipment 11 SOFC
14 Governor 21 Combustor 22 Gas turbine 50, 90, 120 Control device 100, 101 Flow control valve 200 Three-way valve G3 Combustible gas bypass channel G4 Fuel gas channel Q4 Nitrogen gas bypass channel

Claims (9)

A combined power generation system comprising a fuel cell facility or a fuel co-production device, and a gas turbine in which fuel gas output from the fuel cell facility or the fuel co-production device is supplied to the combustor via a fuel gas flow path Because
Combustible gas supply means for supplying the fuel gas flow path with combustible gas purified in the system;
A combined power generation system comprising: control means for controlling the amount of combustible gas supplied from the combustible gas supply means so that the amount of heat generated at the combustor inlet of the gas turbine is constant.   The combustible gas supply means supplies a part of the fuel gas output from the desulfurization facility or the dust removal facility for purifying the fuel gas supplied to the fuel cell facility or the fuel co-production device to the fuel gas passage. The combined power generation system according to claim 1 to be supplied. A combined power generation system comprising a fuel cell facility or a fuel co-production device, and a gas turbine in which fuel gas output from the fuel cell facility or the fuel co-production device is supplied to the combustor via a fuel gas flow path Because
Nitrogen gas supply means for supplying nitrogen gas purified in the system to the fuel gas flow path;
A combined power generation system comprising: control means for controlling the amount of nitrogen gas supplied from the nitrogen gas supply means so that the amount of heat generated at the combustor inlet of the gas turbine is constant.   The combined power generation system according to claim 3, wherein the nitrogen gas supply means supplies a part of the nitrogen gas supplied to the fuel cell facility or the fuel co-production device to the fuel gas flow path. A combined power generation system comprising a fuel cell facility or a fuel co-production device, and a gas turbine in which fuel gas output from the fuel cell facility or the fuel co-production device is supplied to the combustor via a fuel gas flow path Because
Combustible gas supply means for supplying the fuel gas flow path with combustible gas purified in the system;
Nitrogen gas supply means for supplying nitrogen gas purified in the system to the fuel gas flow path;
Control means for controlling the amount of combustible gas supplied from the combustible gas supply means and the amount of nitrogen gas supplied from the nitrogen gas supply means so that the amount of heat generated in the combustor of the gas turbine is constant. And a combined power generation system.   The combined power generation system according to claim 5, wherein the combustible gas supply means and the nitrogen gas supply means are connected to the fuel gas flow path via a three-way valve.   The control means determines the supply amount of the combustible gas and the supply amount of the nitrogen gas based on a value obtained by subtracting an actual heat generation amount at the combustor inlet from a target heat generation amount at the combustor inlet of the gas turbine. The combined power generation system according to claim 6, wherein the opening degree of the three-way valve is adjusted according to the supply amount.   The combined power generation system according to claim 7, wherein the control unit reflects the amount of power generation in the fuel cell facility as a disturbance in a calculation process of the supply amount of the combustible gas and the supply amount of the nitrogen gas. A combined power generation system comprising a fuel cell facility or a fuel co-production device, and a gas turbine in which fuel gas output from the fuel cell facility or the fuel co-production device is supplied to the combustor via a fuel gas flow path The fuel gas heating value control method of
The combustible gas purified in the combined power generation system and / or the nitrogen gas purified in the combined power generation system are used as the fuel gas flow so as to make the calorific value at the combustor inlet of the gas turbine constant. A method for controlling the amount of heat generated from the fuel gas supplied to the road.

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