JPH04128506A - Operation control method for coal gas combined power generation system - Google Patents

Abstract

PURPOSE:To prevent flare discharging caused by upper limit over of gas pressure and gas turbine fuel switching caused by lower limit over of the gas pressure, by setting a function which decides a pressure set value automatically according to a load set value. CONSTITUTION:In a load control unit 32, the operation of deviation between the load value of a load setting device 36 and combined power generation output which is the sum of gas turbine output and steam turbine output, is carried out by a subtracter 37. Its deviation signal is inputted to a proportional-plus-integral device 38, and load control output after operation is outputted to a gas turbine control unit. On the other hand, a gas pressure control set value is set by a pressure function setting device 42. Gas pressure is processed in such a manner as the signal of a gas pressure detector 28 is fed back to a pressure control unit 33 so as to operate its deviation from the signal of a demand pressure setting device 41 by the subtracter 37, and output of the proportional-plus-integral device 38 is outputted to a gasification furnace control unit. At this time, characteristics of a pressure function setting device 42 can present such a function as decreasing a pressure set value when a load set value is high and increasing the pressure set value when the load set value is low.

Description

[Detailed description of the invention]

[Purpose of the Invention (Industrial Application Field) The present invention provides a coal gasifier in which coal gas generated in a coal gasifier is guided to a gas turbine, and the exhaust gas combusted there is used to drive a steam turbine with the steam generated. This invention relates to a method for controlling the operation of a gasification combined cycle power generation system. (Prior Art) In recent years, against the backdrop of the effective use and diversification of energy resources, great expectations have been placed on thermal power generation using coal as fuel, especially from the viewpoint of stability of resource supply and economic efficiency. Among them, a combined coal gasification combined cycle system (called IGCC) combined with a combined cycle plant has attracted attention due to its high power generation performance and environmental compatibility, and is currently under development with the aim of putting it into practical use in the near future. The characteristics of IGCC are its environmental compatibility and compatibility with a wide range of coal types, but it has become even more realistic as power generation efficiency increases due to the recent rise in temperature of gas turbines, making it one of the most promising coal-based power generation options in the future. It is expected to be used as a power generation system.I GCC is a large-scale and complex system consisting of a combined power generation system of coal gasification, gas purification, gas turbine, exhaust heat recovery boiler, and steam turbine. Fast and reliable load response is required for operation. Various GCC systems can be considered depending on the formation of the gasifier and the refining system, and the one shown in Figure 3 is one example. Oxygen is used as the slurry supply and gasification agent.The gasifier 1 is a facility that generates coal gas (referred to as crude gas). However, oxygen gas, which is a gasifying agent, is also introduced through the oxygen flow rate control valve 3, and a high-temperature crude gas (approximately 1,000
'C) is generated. The crude gas produced in the gasifier 1 is passed through the gas cooler 5 until it reaches the allowable temperature at the inlet of the subsequent desulfurization device 6.
It is cooled down and sent to desulfurizer r6. Coal contains at most several percent sulfur, and the sulfur content in this crude gas is destroyed in the desulfurizer 6. After this desulfurization, the coal gas enters the dust removal equipment No. 7 and 2, where fine particles such as ash contained in the gas are removed, resulting in clean purified coal gas (refined gas) and sent to the gas turbine equipment. It will be done. The fuel is sent to the gas turbine 9 via the fuel flow control valve 8 and to the combustor 10 of the gas turbine 9 . Here, the compressor 11 of the gas turbine 9
This combustion gas is sent to the gas turbine 9iZ, and the gas turbine generator 26 generates electricity by the operation of the gas turbine 9. After the gas turbine 9 is activated, the combustion gas reaches a high temperature (about 600℃). °
C), it is sent to the exhaust heat recovery boiler 15, where the heat is recovered, and is released into the atmosphere from the chimney 27 as low-temperature exhaust gas (approximately 100° C.). The exhaust heat recovery boiler (referred to as HR5G) 15 has a super heater 16, an evaporator 17 . Water or steam heat exchangers called economizers 18 are sequentially arranged to recover heat from the exhaust gas energy of the gas turbine 9. First, a portion of the feed water heated by the economizer 18 is sent to the gas cooler tram 13 provided for recovering heat from the gasifier. The steam generated in the gasifier gas cooler drum 13 by heat recovery in the gasifier gas cooler 5 is H
It is collected in the RS G drum 19. In addition, the remainder of the feed water from the economizer 18 is sent to the steam drum 19, and the steam generated by heat recovery in the evaporator 17 is converted from the steam drum 19 to superheated steam (in the state of dry steam) via the superheater [6], which is then turned into superheated steam (in the state of dry steam), which is then turned into superheated steam (in the state of dry steam). Sent to 21. This dry steam is passed through a steam control valve 20 to a steam turbine 2.
] Enters the steam turbine and drives the steam turbine generator 2
2 is parked and generates electricity. On the other hand, the low-pressure wet steam that has worked in the steam turbine 21 becomes water in the condenser 23, and is sent to the two economizers 18 via the feed water heater 24 and deaerator 25, and starts the cycle of becoming steam again. repeat. In IGCC plants such as those mentioned above, power generation is performed by a gas turbine generator 26 and a steam turbine generator 22, and this eight-power regulation is performed by the gas turbine fuel regulation #8.
The steam control valve 20 of the steam turbine is used. Furthermore,
The output of the gas turbine 9 can also be adjusted by adjusting the gas fuel by adjusting the slurry flow control valve 2 of the gasifier and secondarily increasing the fuel flow rate to the gas turbine. Among the three operation ends, the steam control valve 20 of the steam turbine 21 has a large energy transfer response in HR5G15, and the overall efficiency is also better if the steam control valve 20 is fully opened for variable pressure operation. Operation is performed at a constant opening. Therefore, in the overall load operation, the fuel control valve 8 of the gas turbine 9 and the slurry flow rate control valve 2 of the gasifier 1 are the two main operating terminals for controlling the overall plant load. Note that the oxygen flow rate control valve 3 is automatically controlled in response to commands to the slurry control valve 2.

[ru. The quality of load operation for the plant as a whole is determined by how quickly and stably it can follow the load during large load changes. It is necessary to be able to change the load while keeping the plant parameters within an appropriate range so as not to be subject to equipment limitations during this load change process. That is, changes in the load of the entire plant are controlled using the fuel yA moderation valve 8 of the gas turbine 9 and the slurry control valve 2 of the gasifier as operating ends. The control goal is to keep the rise or fall in pressure within limits, which occurs when there is an imbalance between the power output, the amount of gas generated from the gasifier, and the amount of gas consumed by the gas turbine equipment, that is, to keep the gas pressure constant. It is to control. In this way, in controlling the IG CC, the fuel flow rate of the gas turbine 9 or the gas generation amount of the gasifier is controlled based on the load command based on the gas pressure (gas pressure detector 2).
Gas pressure has upper and lower limits and is controlled as follows: There is a pressure relief line at the gas turbine inlet for protection when gas pressure increases. When the pressure signal of the gas pressure detector 28 exceeds the pressure limit value, the flare pressure controller J4 releases excess gas to the flare stack 12 via the flare valve 4 to prevent the gas pressure from rising. Protecting equipment 7 On the contrary to the above, there are restrictions on the gas turbine side when the gas pressure decreases. An auxiliary fuel line is connected to the combustor 10 of the gas turbine, and when the gas pressure falls below a lower limit value, the fuel flow control valve 8 controls the fuel supply to the gas turbine.
The gas turbine is automatically switched from coal-refined gas to the auxiliary fuel of the auxiliary fuel and quantity control valve 29, and the gas turbine is operated on the auxiliary fuel. At this time, the gas fuel adjustment valve is fully closed. In the case of a general thermal power plant, the generated power and steam pressure are the main controlled variables, and the feedback to the steam turbine control valve and the amount of fuel input to the boiler is controlled by the turbine. There are lead and turbine lead methods. In the case of IGCC, the control variables, power generation output and gas pressure, are controlled by the slurry flow rate of the gasifier (accumulative acid flow rate is controlled with the slurry) and the fuel flow rate to the gas turbine. A basic control method as shown in FIG. 4 has been proposed depending on the feedback. Figure 4 (A) is called the gasifier lead method, and corresponds to the turbine lead method in general thermal power plants, and the amount of fuel input to the gasifier is controlled by controlling the power generation output, and the amount of fuel input to the gasifier changes accordingly. The gas pressure is determined by adjusting the amount of gas consumed in the gas turbine 9 by adjusting the fuel flow control valve 8 of the gas turbine 9. Fig. 4 (B) is called a gas turbine lead system, and corresponds to the turbine lead system of general thermal power plants, and the fuel consumption of the gas turbine 9 is controlled by the fuel control valve of the gas turbine 9 by controlling the power generation output. 8, and the gas pressure is controlled using a command value for the slurry flow rate to be supplied to the gasifier 1.The control of these two control methods each has its own characteristics. In other words, in the gasifier lead method shown in Figure 4 (^), due to changes in the MW command, the amount of fuel input to the gasifier 1 increases, so the gas pressure in the system increases, but the pressure at the gas turbine inlet changes. There is a large lag in , so M W i7) increases slowly. However, since the gas turbine flow rate control valve operates quickly to correct the pressure of the gas turbine 9, the gas pressure is controlled stably (almost in accordance with the target practice). On the other hand, in the gas turbine REET method shown in FIG. 4(B), the gas consumption amount in the gas turbine 9 is first increased to follow the MW high output command by changing the MW command. Therefore, the gas pressure within the system decreases. Due to the delay due to the large volume of the gasification and gas purification systems in response to the increase in fuel to the gasifier, the change in gas pressure becomes thicker in proportion to the load change of the MW command.The latter delay in gas pressure is This is explained from the open loop simulation results shown in Figure 5. Figure 5 shows the gas pressure, combined power output C1, and gas turbine fuel gas flow rate when the slurry flow rate a, which is the gasifier input, is varied in a ramp-like manner. d and changes in the steam turbine output direction e, etc. Here, the fuel control valve 8 of the gas turbine 9 performs pressure control to keep the gas pressure constant.Changes in the slurry flow rate a The gas pressure b follows after a long delay, and the fuel control valve 8 of the gas turbine 9 quickly responds to this change in pressure and changes the MW output C, but there is a delay from the slurry change to the gas pressure change. Therefore, the response is slow as well as the MW output C gas pressure.In other words, there is a large time delay from the slurry change to the gas pressure change.Therefore, the gas turbine lead method shown in Fig. 4(B) The reason why the gas pressure changes greatly is that even if you capture the pressure change and change the slurry, the pressure will not follow up due to the large delay in the gasifier and gas purification system. If the MW small output response is prioritized as a plant and the gas pressure is within the limits of the equipment, of the above two methods, the gas turbine lead method shown in Figure 4 (B) can be said to be the preferred control method from an operational point of view. The control logic of the gas turbine lead mode in FIG. 4(B) will be explained using FIG. 6. In the figure, the gasifier 1
, coal slurry control valve 2. Gasifier 8 consisting of oxygen flow control valve 3, combustor 10, compressor 11, gas turbine 9
, a gas turbine installation consisting of a fuel flow control valve 8 is shown. Detection of power generation from gas turbine equipment power generation 926 @3
0a, the generated power detector 30b signal from the steam turbine generator 22, and the gas turbine inlet pressure detector 2.
The signal No. 8 is guided to the plant control device 31. The plant control unit N31 includes a load control unit 32, a pressure control unit 33,
It is composed of a gasifier control section 34 and a gas turbine control section 35. In the load control unit 32, the output of the generated power detector 30 and the set value from the required load setter 36 are input to a subtracter 37, and after the subtraction process, the deviation signal is led to a proportional integrator 38 for proportional integration. An operation is performed. The value after the proportional integral processing is input to the gas turbine control unit 35 as a gas turbine control m order, and after signal adjustment in the pressure control system 43 and exhaust temperature control system 39 within the gas turbine control unit, it is input from the low value priority device 40. The signal is output to the fuel flow control valve 8 as a control command signal. That is, the fuel flow rate to the gas turbine 9 is reduced by y4 to eliminate the load deviation, and as a result, the output of the gas turbine 9 is controlled to match the load MQ''l value by this fuel flow rate. In the pressure control unit 33, the input signal from the gas turbine inlet pressure 28 and the set value from the required pressure setting device 41 are input to a subtracter, and after the subtraction processing, the deviation signal is guided to the proportional integrator 38 for proportional integral calculation. The value after the proportional integral processing is inputted to the gasifier control unit 34 as a gasifier control command signal.In the gasifier control unit 34, it is sent to the coal slurry control valve 2 based on the gasifier control command signal. The slurry flow rate adjustment signal and the flow rate adjustment signal to the raw flow j!l control valve 3 necessary for gasification based on the slurry flow rate command are output, respectively.In other words, the slurry and oxygen are sent to the gasification furnace 1. The injection of gas is controlled to eliminate deviations in gas pressure and maintain a constant gas pressure with respect to the load. Modification number 3: Change in load and pressure during load increase and load decrease during gas turbine lead mode. An example of the response results is shown in Fig. 7. Fig. 7E (A) shows the response when the load decreases and increases in elementary and middle schools. 1 is always a constant value.P is a pressure response, and if the load starts to drop at time t, then the consumption of refined gas in the gas turbine is reduced according to the load drop, so the fuel flow rate As the control valve is closed, the pressure rises to -.MWS is the load (MW small output setting value, and CCMW is the combined power generation output that is the sum of the outputs of the gas turbine and steam turbine.Next. , when the load increases, the pressure shows an opposite response to when the load decreases1, and although the pressure decreases significantly, the load response is smooth.The pressure fluctuations in this gas turbine lead mode vary depending on the load change range. It is almost proportional, and when the load change width is large, the pressure change also becomes large.As mentioned above, the disadvantage of this method is that the gas pressure change is large.This pressure change (when the load increases) is a decrease in pressure, and when the load decreases, the pressure increases), but as the range of load change increases, the rate of decrease in pressure (or L) tends to increase. This is because the accumulation of the unbalanced difference between the amount of gas fuel consumed in fuel adjustment #8 and the amount of gas generated by the gasifier increases as the load change range becomes larger. During large load changes during the load rise and evening load drop periods, the pressure drop (or pressure rise) due to pressure follow-up delay may become an impediment to the load change. Regarding gas pressure, there are several limiting factors that the plant should consider: One of them is the upper limit on gas pressure. The upper limit of gas pressure is determined by the design value of the gas system including the gasifier, and if the pressure rises above the upper limit, the pressure relief valve is operated to release the excess until the pressure reaches the specified value. Gas flare stack 12 (or gas processing furnace)
We are using a method to release it to Next, regarding the lower limit of pressure, if the gas pressure (at the gas turbine inlet) is not above a certain value, it will deviate from the control range of the fuel control valve on the gas turbine side and become uncontrollable. Gas pressure must be maintained. If the gas pressure decreases due to a large load increase and falls below the gas pressure inlet control value for the gas turbine 9, the gas turbine 9 will automatically stop generating electricity using gas fuel and switch to auxiliary fuel. It has an interlock. During this time, the gas pressure is restored because no gas is consumed, and the auxiliary fuel is switched to gas fuel again. However, if fuel switching fails, it will result in a gas turbine trip, and this is an operation that should be avoided during normal load changes. FIG. 7(B) shows the response when the above problem occurs due to a large load change. At point t2 during the load increase in Figure 7 (B), the gas pressure P exceeds the flare set value P, so excess gas is released from the flare to the atmosphere, and as a result, the gas pressure P decreases to the flare set value P0. is controlled to a constant value, and load changes are made according to the set value, but releasing gas into the flare itself is a loss of fuel and is an environmental problem, so it is a phenomenon that should be avoided. Further, when the load increases, the gas pressure P decreases so much that at point t1, the gas pressure P drops so much that it reaches the allowable lower limit P1- of the gas turbine inlet pressure, causing fuel switching of the gas turbine. When the fuel of the gas turbine 9 is switched, the gas turbine 9 generates an output using the auxiliary fuel, and during this time, no purified gas is consumed, so the unused purified gas helps the gas pressure P recover, and the gas pressure P recovers quickly. (Problem to be solved by the invention) As mentioned above, the gas turbine lead mode with excellent load response is the optimal control method for load control of future coal gasification combined cycle power generation, but its biggest drawback is that the gas turbine lead mode has excellent load response. There is a pressure fluctuation, and the greater the load change i during this fluctuation, the greater the gas pressure fluctuation. In future intermediate load operations, gas turbine fuel switching due to a large drop in pressure (or flare valve operation due to a large increase in pressure) during a large range of load changes during the morning load rise and evening load fall periods will result in load changes. inhibiting factors, leading to a decrease in overall efficiency. The object of the present invention is that the direction of pressure change when the load changes is the load F.
Focusing on the fact that pressure increases at any time and pressure decreases when load increases, we have created a function that automatically determines the pressure setting value based on the load setting value, and uses this function to automatically set the pressure setting depending on the load. It is an object of the present invention to provide a control device that realizes load control using an optimal gas turbine lead mode that does not cause flare emission due to exceeding the upper limit of gas pressure and fuel switching of the gas turbine due to exceeding the lower limit of gas pressure. [Structure of the Invention] (Means for Solving the Problems) In order to solve the above problems, the present invention automatically sets the pressure setting value variably according to the load setting value, and lowers the pressure setting value when the load setting value is high. , the pressure setting value is set high when the load setting value is low, thereby providing a margin for the upper and lower limits of the pressure. (Function) That is, when the load is high, the pressure setting is low, so even if the pressure increases when the load drops from a high load, the pressure starts from a stable state with low pressure. Therefore, there is a margin for the upper pressure limit by the amount of the low pressure setting. Conversely, when the load is low, the pressure setting is high, and when the load increases from this point on, the gas pressure moves in the direction of decreasing pressure, but there is still room for the lower pressure limit by the amount that the pressure setting is set high. Become. (Embodiment) FIG. 1 shows a configuration diagram of a control system according to an embodiment of the present invention. The same elements as in FIG. 6 are given the same reference numerals, and their explanations will be omitted. The feature of the present invention is that the pressure setting of the pressure control unit 33 is automatically set to the required pressure setting device 41 via the pressure function setting device 42 using a function generator based on the signal of the load setting device 36. It is. The characteristics of this pressure function setting device 42 are shown in FIG. 2(A). That is, the function is such that when the load setting value is high, the pressure setting value is low, and when the load setting value is low, the pressure setting value is high. FIG. 2(B) is a diagram showing the response of pressure when the load changes according to the present invention in comparison with the conventional example. ps is the pressure setting value (constant value) in the conventional example, P is the change in gas pressure in the conventional example, P' is the change in gas pressure in the present invention,
ps' is the pressure setting value in the present invention, PHL is the upper limit value of pressure (flare valve operating pressure), PL, ■. is the lower limit value of pressure (gas turbine fuel switching setting value). Changes in the load setting value and actual load both indicate changes in the present invention. FIG. 2(B) shows the response of the load and pressure when the load setting device 36 of the load control section 32 receives an intermediate supply command from the central power dispatch center and changes the load. In FIG. 2(B), both the pressure and the load are in a stable state before reaching time t1. That is, the pressure set value is automatically set from the load set value via the pressure function setter 42, and the gas pressure PS' is controlled to be constant at this set value. The combined power generation output CCMW, which is the sum of the gas turbine output and the steam turbine high power, is also in a stable load state that matches the load setting value MWS. Here, the load change starts at time t when the intermediate feed command enters the load setting device 36 of the load control 32. According to the load change from time t1, the pressure setting value PS' is also automatically set and changed according to FIG. 2 (^). In the load control section 32, a subtracter 37 calculates the deviation between the load setting value given from the load setting device 36 and the combined power generation output, which is the sum of the gas turbine output and the steam turbine output. The deviation signal is input to the proportional integrator 38. The calculated load control output is output to the gas turbine control section 35. A control output is output from the gas turbine control unit 35 to the fuel flow control valve 8, and the opening degree of the fuel flow control valve 8 is adjusted in the closing direction, and the gas turbine output is adjusted in the decreasing direction. As the fuel consumption in the gas turbine 9 decreases, the gas pressure increases. On the other hand, the gas pressure control setting value is set by the pressure function setting device 42, and the second output is set in the decreasing direction gs
be done. As the fuel consumption in the gas turbine 9 decreases, the gas pressure increases. On the other hand, the gas pressure control set value is set by the pressure function setter 42 and changes as shown by PS' in FIG. 2(B). In FIG. 2(B), the signal of the gas pressure detector 28 is fed back to the pressure control unit 33, and the subtracter 37 calculates the deviation from the signal of the required pressure setting device 41. is output to the gasifier control unit 34, and the gasifier slurry flow rate, W! As a result of the elementary flow rate being adjusted in the decreasing direction, the gas pressure changes as indicated by P' in FIG. 2(B). Figure 2 (B) also shows the change in pressure setting value and gas pressure in the conventional example.
is shown. In the conventional example, the gas pressure setting value is shown in Figure 2 (
B) It is a constant value like the middle PS, and it has already settled at a higher pressure than the pressure in the present invention at the time t when the load drop starts, and the pressure increases as the load drops. Time t in Figure 2 (B)
2, the pressure limit (Pl'(L)) is exceeded, resulting in flare control operation.In the conventional example, the pressure returns to the pressure set value only after the load drop ends, and the flare control operation occurs for a considerable period of the load drop. The valve operation continues. In Fig. 2 (B), there is no load change between time t4 and time t5, and the load pressure is stable in a stable state. Regarding pressure, in the present invention, the pressure settling point is the point at which the load is The lower the pressure, the higher the pressure, so the pressure is set higher, but in the conventional example, the pressure setting point is set at a constant pressure regardless of the load.Next, from time t in Fig. 2 (B) When the load starts to increase, the combined power generation output increases.The increase in the combined power generation output increases the fuel consumption of the gas turbine, and the gas pressure decreases.This decrease in gas pressure is fed back to the gasifier. The gasifier control unit operates to increase the slurry and oxygen and pull back the gas pressure, but the response of the gas pressure is delayed due to the volume of the gasifier and gas purification system, as shown in Figure 2 (B). The change in pressure at this time is: Contrary to the above-mentioned increase in load, the pressure changes with a slight undershoot, but the change in gas pressure in the present invention is faster than the change in pressure. The drop is small because the pressure setting value is high.In the conventional example, the pressure falls below the lower limit point (i-'L, L) at time t in Figure 2 (B), and in the conventional control, this point In this case, fuel switching of the gas turbine occurs, and automatic switching from coal gas fuel to auxiliary fuel occurs.In the present invention, the pressure itself changes higher than the gas pressure change in the conventional example, so fuel switching does not occur. 5. In this way, the pressure setting value is automatically set variably according to the load setting value, and when the load setting value is high, the pressure setting is set low, and when the load setting value is low, the pressure setting value is set high, and the upper limit of the pressure is set. There is a margin at the lower limit, and when the load is high, the pressure setting value is low, so even if there is a pressure increase when the load drops from a high load, the pressure will start from a low and stable state, so the pressure will increase by the amount of the low pressure setting. There is a margin for the upper limit. Conversely, when the load is low, the pressure setting is high. Therefore, when the load increases from this point, the gas pressure moves in the direction of decreasing pressure, but the pressure setting is set high. There is a margin for the lower pressure limit to the extent that
Compared to conventional control where the pressure setting is constant, there is a margin for pressure change from the gas pressure limit value, so there is no flare release due to the gas pressure exceeding the upper limit, and gas turbine fuel switching due to the gas pressure exceeding the lower limit. Load control using the optimal gas turbine note mode can be achieved. In the present invention, the load setting value is used as the input to the pressure setting function generator, but any parameter equivalent to the plant output, such as actual load or fuel flow rate, can be substituted. [Effects of the Invention] As described above, according to the present invention, gas is discharged into the atmosphere (flare operation) by suppressing fluctuations in gas pressure by operating in the gas turbine lead mode, which is optimal for intermediate load operation.
There is no fuel switching (2), so there is no time loss during startup load change time, and it is possible to provide an optimal operation control method for a coal gasification combined cycle power plant that can achieve the maximum load change rate. I can do it.

[Brief explanation of the drawing]

Figure 1 is a system configuration diagram of an embodiment of the present invention, and Figure 2 (
A) is a characteristic diagram of the pressure function setting device of the present invention, and FIG. 2 (B'
) is a characteristic diagram showing the pressure response when the load changes according to the present invention,
Figure 3 is an overall configuration diagram of a coal gasification power plant, Figure 4 is a block diagram of the basic load pressure control method of a coal gasification power plant, and Figure 5 is an open loop simulation result for changes in gasifier input. Fig. 6 is a control configuration diagram showing a conventional example, and Fig. 7 is a characteristic diagram showing an example of the response results of load and pressure when the load is raised and lowered at the gas turbine lead motor in the conventional example. . l Gasifier, 2... Coal slurry control valve 23 Oxygen flow control valve, 4. Flare valve, 5 Gas cooler, 6. Desulfurization device, 7. Dust removal device, 8. Fuel flow IT control valve, 9. Gas Turbine, 10. Combustor, 11. Compressor, 12. Flare stack, 13. Gas cooler tram, 14. Flare pressure controller, 15. Exhaust heat recovery boiler, 16.
・Super heater,】7 Evaporator, 18・Economizer, 19...HRS G drum, 20・Steam control valve. 21. Steam turbine, 22... Steam turbine generator,
23. Condenser, 24.. Feed water heater, 25.. Deaerator,
26... Gas turbine generator, 27... Chimney, 28...
・Gas pressure detector, 29 ・・Auxiliary fuel flow rate control valve, 30
・・Generated power detector, 3-dovelant control device, 32・・
- Load control section, 33. Pressure control section, 34. Gasifier control section, 35. Gas turbine control section, 36. Demand load setter, 37. Subtractor, 38 Proportional integrator, 39.
・Exhaust humidity control system, 40...Low value priority device, 41.Required pressure set value. Agent Patent Attorney Crest 1) Makoto Diagram φ'fl Set γ- (A) Figure 2 (A) (B) Figure 4 Figure

Claims (1)

[Claims] In a method for controlling the operation of a coal gasification combined cycle power generation system in which coal gas generated in a coal gasification furnace is guided to a gas turbine and a steam turbine is driven by steam generated using exhaust gas burned therein, the entire coal gasification combined power generation system is provided. The fuel consumption of the gas turbine is adjusted based on the combined power generation output, which is the output of The supply amount command of the slurry flow rate is adjusted to match the gas pressure set value, and when the load set value is high, the gas pressure set value is set low, and when the load set value is low, the gas pressure set value is set low, and when the load set value is low, the gas pressure set value is set low. An operation control method for a coal-gas combined power generation system, characterized in that the gas pressure of the coal gas is controlled by setting a gas pressure setting value high.