JPH0323302A - Coal gasification power generating plant - Google Patents

Abstract

PURPOSE:To enable operation of the plant in this title in safety within the restricted value of a gas turbine at the time of a gas turbine restricting control condition, by making correction for increasing/decreasing a load set value used in a load control unit according to the fuel flow rate adjusting valve opening and pressure deviation quantity. CONSTITUTION:In a power generating plant provided with a gasification furnace facility including a gasification furnace 1 and a gas turbine facility including a compressor 9 and a gas turbine 10, a power generator output detector 26, inlet pressure detectors 27, 28 relating to a fuel pressure adjusting valve 6 and a fuel flow rate adjusting valve 7, and a valve opening detector 29 for the fuel flow rate adjusting valve 7, and provided. And in a plant control device 63, when a gas turbine facility is not selected in gas turbine pressure control in a gas turbine following mode, the output signal of a controller 85 for inputting a pressure deviation in a pressure control unit 67, and a control function which is generated in a function generator 84 on the basis of a valve opening, are taken out by a changeover switch 80, so that a load setting value in a load control unit 66 is increased/decreased by an increasing/decreasing setting device 86 on the basis of its output thereof.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a coal gasification power generation system 1. In particular, the present invention relates to a coal gasification power generation system that stabilizes operation by improving a plant-based WJ device. Regarding power plants.

(Prior art) A coal gasification power plant converts coal into gas fuel and uses the gas as a working fluid source to rotate a gas turbine and a compressor, as well as to rotate a generator, making efficient use of energy. , is attracting attention for its superiority in pollution problems.

Among these power generation plants, coal gasification combined cycle power plants lead the exhaust heat of the gas turbine to the boiler, and use the steam obtained by heat exchange with the exhaust heat and the heat exchanger (cooler) of the gasifier.
The generated steam is guided to a steam turbine to generate electricity, and has a major feature of extremely high heat recovery capacity.

FIG. 2 is a schematic diagram showing such a coal gasification combined cycle power plant system.

Coal is sent to a gasification furnace 1 for producing crude gas via a coal amount adjustment device 2, and an oxidizer amount adjustment device 3.
An oxidizing agent such as air is sent through the tank.

The crude gas produced in the gasifier 1 is sent to the gas purification device 5 via the gas cooler 4, where the fuel gas is purified. The fuel gas is sent to the combustor 8 via the fuel pressure regulating valve 6 and the fuel flow regulating valve 7, and is combusted by air pressurized by the compressor. The gas turbine 10 is driven by this combustion gas, and the generator 11 generates electricity.

Note that the air pressurized by compression I1!9 is
The oxidizing agent is further compressed by the internal pressure compressor 12 driven by the oxidizing agent 3, and is supplied to the oxidizing agent flow chamber 3.

On the other hand, after the combustion gas drives the gas turbine 10, it is sent to the exhaust heat recovery boiler 15 as exhaust gas from the gas turbine 10. This exhaust heat recovery boiler 15 has a superheater 16, an evaporator 17, and an economizer 18 in order from upstream with respect to the flow of exhaust gas, and the thermal energy of the exhaust gas is recovered here, and steam is converted to steam by these heat exchangers. Occur. That is, part of the feed water heated by the economizer 18 is sent to the gas cooler drum 14 and the rest is sent to the steam drum 19. The feed water sent to the gas cooler drum 14 is circulated to the gas cooler drum 14 via the gas cooler 4, and the steam generated during this circulation is sent from the gas cooler drum 14 to the super heater 16. The feed water sent to the steam drum 19 is returned to the steam drum 19 via the evaporator 17, and the steam generated during this time is also sent to the super heater 16.

The dry steam generated by the sub-heater 16 is sent to the steam turbine 21 via the steam control valve 20, and is then sent to the generator 2.
It is used for the second drive, that is, for power generation.

The steam that has lost energy by driving the steam turbine 21 is sent to the condenser 23, where it undergoes indirect heat exchange with cooling water, is brought to approximately room temperature, and returns to water. This water is sent to the economizer 18 via the feed water heater 24 and the deaerator 25, where it is vaporized again.

By the way, as is well known, the entire plant is operated in a gas turbine follow-up mode and a gasifier follow-up mode, and one of these modes is selected depending on the purpose.

In the gas turbine follow-up mode, the gasifier equipment consisting of the gasification furnace 1, the coal planting adjustment device 2g'3, the oxidizing agent amount adjustment device 3, etc. performs load control, and the combustor 8, compressor 9, gas turbine The gas turbine equipment consisting of the 101 electricity generation ILffi feed pressure regulating valve 6, the fuel flow regulating valve 7, etc. is in a mode in which the gas turbine inlet gas pressure (or the gas purification equipment inlet gas pressure) is controlled.

Further, the gasifier follow-up mode is a mode in which the gas turbine equipment performs load control and the gasifier equipment controls the gas turbine inlet gas pressure.

In general, the gasifier follow-up mode has the advantage of being able to generate electricity without a large delay with respect to the required power generation skewer, but since the gas pressure supplied from the gasifier 1 is accompanied by a large delay, it is especially The disadvantage is that the gas pressure fluctuates greatly when the load changes.

On the other hand, the gas turbine tracking mode has the advantage of maintaining a stable state without large fluctuations in gas pressure even when the load changes, etc., contrary to the gasifier tracking mode, but the power generation output is Since it changes with the delay, there is a drawback that fltlJtll is significantly delayed when the load changes.

That is, from the standpoint of load requirements, the gasifier follow-up mode has an advantage, and from the standpoint of stable operation of the system, that is, prevention of equipment wear, the gas turbine follow-up mode has an advantage.

In a coal gasification power plant, the temperature inside the gasifier is 1400℃.
Because the temperature is as high as ~1600℃, ordinary metal materials cannot be used, and bricks, etc., are used to cope with the problem, but sudden changes in the furnace environment, such as the temperature inside the furnace, are factors that accelerate the deterioration of bricks. becomes. However, in order to achieve more stable operation of the system, the gas turbine tracking mode is often used.

FIG. 3 shows an example of a conventional control circuit in the gas turbine follow-up mode.

The figure shows gasifier equipment consisting of a gasifier 1, a coal fit adjustment device H2, and an oxidizer a adjustment device 3, a combustor 8, a compressor EL 9, a gas turbine 10, a power generator 11, a fuel pressure adjustment valve 6, and A gas turbine installation consisting of a fuel flow regulating valve 7 is shown.

Generator output detector 2 on the gas turbine equipment generator IHL11
6, an inlet pressure detector 27 is provided upstream of the fuel pressure regulating valve 6, and an inlet pressure detector 28 is further provided upstream of the fuel flow regulating valve 7. These generator output detectors 26 and each inlet pressure detector 27, 2
Detection signals 101, 102, and 103 from 8 are input to a plant control device 29, respectively.

The plant control device 29 includes a gasifier control section 30, a gas turbine tilJ m1 section 31, a load control section 32, and a pressure control section 33.

In the load 2ilJ II1 section 32, the increaser 34 or (
A load setting signal 104 is output from the load setting device 36 operated by the reduction operation device 35, and the load change rate limiter 37
is input to. In this load change rate limiter 37, the load setting signal 104 is increased or decreased by a preset change rate value, and then outputted as an output signal 105. Then, the output signal 105 and the output signal 1 of the generator output detector 26 inputted to the plant control device 29
01 is subjected to subtraction processing in the subtractor 38, and the deviation signal 106 obtained by {q is input to the proportional integral element 39, where a proportional k1 calculation is performed. The daughter after the ratio 11'lM processing is inputted to the gasifier control unit 30 as a gasifier control command signal 107, and based on this gasifier control command signal 107, the respective input amounts of coal and oxidizer are adjusted to IIJ. '10 is calculated, and then output as a control command signal 108 for the coal amount adjustment device 2 and a control command signal 109 for the oxidizer amount adjustment device 3.

On the other hand, in the pressure control unit 33 , a pressure setting signal 110 is outputted from a pressure setting device 42 operated by an increasing operation device 40 or a decreasing operation device 41 and inputted to a pressure change rate υ limiter 43 . In the pressure change rate υ1 limiter 43, the pressure setting signal 110 is increased or decreased by a preset change rate value, and then outputted as an output signal 111. Then, this output signal @111 and the output signal 102 from the inlet pressure detector 27 of the fuel pressure regulating valve 6 inputted to the plant control device 29 are subtracted in the subtractor 44,
The Q difference signal 112 obtained here is input to the proportional-integral element 45, and a proportional-integral operation q is performed.

The value after the proportional integral processing is input to the gas turbine control unit 31 as the gas turbine llI command signal 113, and after the fuel gas flow rate is controlled and calculated based on the gas turbine υI'ml command signal 113, the fuel flow rate is adjusted. Sub I to valve 7
It is output as an IIM command signal 114.

Note that a signal 103 from the gas inlet pressure detector 28 of the fuel flow rate regulating valve 7 is input to the gas turbine control section 31.

Based on the calculation result in the gas turbine control section 31, lIjtI
l signal 115 is output to the fuel pressure adjustment valve 6, and this control signal 115 causes the fuel pressure adjustment valve 6 to keep the gas inlet pressure of the fuel am adjustment valve 7 constant at all times, and also to control the fuel in case of an abnormality. Controlled to shut off suddenly.

With the above configuration of the plant i/I tIl device 29,
The gasifier equipment controls the load υ11211, and the gas turbine equipment controls the pressure, so the required load is obtained and
It becomes possible to set the pressure inside the gas system to a desired value.

(Problems to be Solved by the Invention) In recent years, with regard to the upper limit of gas turbine inlet quality, there has been remarkable improvement in cooling technology for turbine blades, combustors, etc.
Gas turbines with an S1 point of about 1,300 to 1,400°C have come into practical use, and the development of ceramic turbines and combustors is progressing, and the design rated point of the turbine inlet temperature will continue to rise in the future. It seems that they will continue to do so. In particular, in coal gasification power plants, when combined power generation with a steam turbine is performed using a gas turbine operated at a gas turbine inlet temperature of about 130<1°C, the thermal efficiency is higher than that of the steam turbine or higher. There are also estimates that it can be achieved, and raising the gas turbine inlet temperature is of particular interest.

However, as is well known in the art of gas turbine equipment, when the suction flow rate in the compressor 9 is constant, as the amount of fuel input increases, the output of the generator increases, and the temperature inside the combustor 8 increases. . Therefore, in response to a request for an increase in fuel that deviates from the design point temperature, it is necessary to limit the increase in fuel in order to protect the gas turbine. It is provided within the control circuit 31.

Generally, gas turbines for power generation are designed so that a rated load can be obtained when the atmospheric temperature is 15° C. and the gas turbine inlet temperature is the rated point temperature. Therefore, when the atmospheric temperature rises, such as in the summer, the density of the air becomes lighter, and the mass flow rate of the air decreases because the flow rate of the air absorbed from the atmosphere by the gas turbine is constant. do. For this reason,
If the gas turbine inlet temperature is operated at the design point temperature, the amount of generated R power that can be obtained will be lower than the rated point. Therefore, when the load request signal when the atmospheric temperature rises is at the rated point, the gas turbine tIlIIa section 31 operates at a pressure equal to or higher than that in order to obtain the rated point gas flow. Based on the signal from the IJ m section 33, the fuel flow rate υ Jail valve 7 is opened, but when the gas turbine inlet temperature reaches the rated point, the IIJ (not shown) is opened to prevent further fuel increase. Limited I
The IJ'II system limits the valve flow rate of the fuel flow control valve 7 so that the gas turbine can operate safely.

However, the gas turbine I! in a coal gasification power plant! The limit control ill lh operation in the control unit 31 means non-selection of the lIIIO command signal 113 to the gas turbine control unit 31. That is, in the gas turbine follow-up mode, the generated gas pressure and in the gasifier follow-up mode, the generated power are both in a non-controlled state. Particularly in the gas turbine follow-up mode, the generated gas pressure is not controlled, and as a result, the gas pressure increases or decreases, making it impossible to operate the system stably, which is the purpose of this operation mode.

The present invention has been made in view of the above circumstances, and provides a coal gasification power plant in which the system can be operated stably without abnormal fluctuations in the generated gas pressure even when the gas turbine is at the υ1 limit lI1m. It is something.

[Structure of the invention]

(Means for Solving the Problems) The present invention provides gasifier equipment that gasifies coal, gas turbine equipment that uses coal gas generated in this gasifier equipment as fuel, and uses heat from gas turbine exhaust gas. The steam turbine equipment, the power generation system provided in each of the turbin equipment, the gasifier equipment and the gas turbine equipment are tllt.
In the coal gasification power plant having a plant control device that
a pressure section that sets the gas pressure to a required value based on the detected value of the gas pressure supplied from the cassification furnace; and a gas control section that controls the gas turbine equipment based on the output signal R from this pressure control section. A turbine control unit, a load control unit that detects the output of the power generation system and sets the output to a required value, and a gasifier that controls the gasifier equipment based on the output signal from the load control unit! 1JIII Division and
a controller that inputs the deviation signal of the pressure it, II II1 section as a reference signal; a function generator that takes in the opening degree of the fuel flow rate regulating valve of the gas turbine equipment and generates a control II number; and a gas turbine. When the ti-period gas turbine equipment is in the non-selected state of the signal from the pressure control unit under the follow-up mode, the above! A switch that takes in each output signal from the II titer and the function generator, and an increase/decrease setting device that increases or decreases the load setting value based on the output signal from the switch. .

(Function) According to the present invention, when the coal gasification power plant control device is operated in the gas turbine follow-up mode and the gas turbine control section enters the limit ill all state, the switch switches the pressure deviation signal to and the opening degree of the fuel flow regulating valve of the gas turbine equipment, so that the load setting value is based on
The output of the load setter is tracked, and thereby the gas pressure is quickly brought to a predetermined value υ11l.

(Example) An embodiment of the present invention will be described below with reference to FIG.

Note that the coal gasification combined cycle power plant, which is the l+III target of this embodiment, is the same as that shown in FIG. 2, so FIG. 2 will also be used as is for explanation of this embodiment.

The figure shows gasifier 1, coal a adjustment equipment! 2 and oxidizing agent I
Gasifier equipment consisting of an N adjustment device I3, and gas turbine equipment consisting of a combustor 8, a compressor 9, a gas turbine 10, a power generator 11, a fuel pressure adjustment valve 6, and a fuel flow adjustment valve 7 are shown. There is.

A generator output detector 26 is provided at the starting point 11 of the gas turbine equipment, and an inlet pressure detector 27 is provided upstream of the fuel pressure regulating valve 6. Further, an inlet pressure detector 28 is provided on the upstream side of the fuel flow regulating valve 7, and a valve opening degree detector 29 is further provided at the fuel flow #llvA regulating valve 7. Detection signals 201, 202, 203, 203a from the generator output detector 26, each inlet pressure detector 27, 28, and the valve opening detector 29 are input to the plant control system [63]. ing.

The plant control system 163 includes a gasification furnace control section 64, a customer service >II section 65, and a load u [II section 66].
and a pressure ill section 67.

In the load II 611 section 66 , the load setting signal 204 is output from the load setting device 70 operated by the increase operation device 68 or the decrease operation device 69 and is input to the load change rate limiter 71 . In this load change rate limiter 71, the load setting signal 204 is increased or decreased by a preset change rate value, and then outputted as an output signal 205. Then, the output signal @205 and the output signal 20 of the generator output detection B26 inputted to the plant 271111 device 63
1 is subtracted by the subtractor 72, and the obtained deviation signal 206 is input to the proportional-integral element 73, where a proportional-integral calculation is performed. The values after the proportional integral processing are input to the gasifier tits section 64 as the gasifier v1 command signal 207, and based on this gasifier II/III command signal 207, the respective input amounts of coal and oxidizer are determined as illt[ 1 is calculated, and then output as a control command signal 208 for the coal amount adjustment device 2 and a control command signal @209 for the oxidizer loss adjustment device 3.

On the other hand, in the pressure itll control section 67, a pressure setting signal 210 is output from the pressure setting device 76 operated by the increase operation device 74 or the decrease operation device 75, and the pressure change rate υ1 limiter 77
is input to. In the pressure change rate limiter 77, the pressure setting signal 210 is increased or decreased by a preset change rate value, and then outputted as an output signal 211. This output signal 211 and the inlet pressure detector 2 of the fuel pressure regulating valve 6 are input to the plant iii1 control device 63.
The output signal 202 from 7 is subjected to subtraction processing in an attenuator 78, and the deviation signal 212 obtained here is input to a proportional integral element 79, where a ratio FA integral calculation is performed.

The value after the proportional integral processing is input to the gas turbine control unit 65 as a gas turbine a, II 'm command signal 213, and the fuel gas flow rate is controlled based on this gas turbine control command signal 213. After that, DI to fuel flow adjustment valve 7
It is output as an ill command signal 214.

Note that the signal 203 from the gas inlet pressure detector 28 of the fuel 111ffil valve regulator 7 is input to the gas turbine control unit 65. According to the calculation result in the gas turbine control section 65, l
The il11II signal 215 is output to the fuel pressure regulating valve 6, and this control signal 215 causes the fuel pressure regulating valve 6 to keep the gas inlet pressure of the fuel flow ffi regulating valve 7 constant at all times, and to control the fuel flow in the event of an abnormality. They were restrained so that they were rapidly cut off.

In this device, a function generator 84, an I limiter 85, and a switch 86 as an increase/decrease setting device are provided between the load control section 66 and the pressure control section 67.

The function generator 84 includes an opening degree detector 2 of the fuel flow adjustment valve 7.
The detection signal 213a from 9 is input, and the v1 control function is generated by taking in the opening degree of the fuel flow ffi regulating valve. On the other hand, the uJail device 85 has a pressure ill control section 6.
A control signal 212 from 7 is input.

Both output signals 217 and 218 from the function generator 84 and the controller 85 are added together, and the sum signal 21
9 is input to the switch 86. Additionally, a zero signal 220 is also input to the switch 86 . Then, the switch 86 selects the selection signal 221, t, T, and negative v by the following selection operation.
IMmM66(7)fl? A signal is output to the LiQf device 70.

That is, the switch 86 does not switch to the selection signal 221 in the normal operating state.
, the zero signal 220 is selected and output, but the control signal @213 from the pressure control section 67 is output to the gas turbine tile.
When the unit 65 enters a non-selected state, that is, other v1
When the gas turbine υjllll section 65 is set to υ+a by the limited IJ 110 system and is operated in the gas turbine follow-up mode, the selection signal 221 switches from the zero signal 220 to the addition signal 219, and the load setting device It operates so that 70 becomes 1・racking. That is, in the above state, the output of the load setting device 70 is based on the gas turbine fuel valve opening degree, and is output from the reference load setting value outputted by the function generator 84 and the controller 85 which receives the pressure deviation as input. This is the sum of the output signal of Therefore, the gas turbine is in a limited control state and the fuel flow regulating valve 59
When the load setting device 70 is throttled, the load setting value of the load setting device 70 is first pulled back by the output of the function generator 84, and then is increased or decreased according to the pressure deviation, so that the predetermined pressure is quickly reached.
lt[I is what is done.

According to such an embodiment, when the coal gasification power plant is operated in the gas turbine follow-up mode and the gas turbine control section enters the limit II'Ia state, the load setting value is changed to the pressure deviation signal. 212 and the fuel flow ffi adjustment valve opening signal 203a, the load set value is racked by 1 by the switch 86 and adjusted to a predetermined gas pressure.

Note that the limit iIJtll of the gas turbine is applicable not only to the limit 11Jtill due to the increase in the gas turbine inlet D temperature, but also to all iilL limit controls in which the control command value from the pressure control section is not selected.

〔Effect of the invention〕

As described above, according to the coal gasification power plant according to the present invention, since the load setting is increased or decreased according to the fuel R flow suspension adjustment valve n degree and the pressure deviation amount, the gas turbine follow-up mode In this case, even if the gas turbine enters the gas turbine limit control state due to the gas turbine inlet temperature limit control value being reached due to an increase in fuel gas consumption due to an increase in the fuel gas generated from the gasifier, the operation of the gas turbine may be interrupted. It can now be done safely within the limit of 1n, and
Effects such as making it possible to perform optimal load operation and pressure operation for the entire plant are produced.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the i,11 all system showing one embodiment of the coal gasification power plant according to the present invention, and FIG. 2 is a system diagram showing the entire system of the coal gasification power plant.
FIG. 3 is a block diagram showing a conventional example. 1... Coal gasifier (gasifier equipment), 2... Coal amount adjustment device (gasifier equipment), 3... Oxidizer adjustment device W (gasifier i1 (&i), 7 ...Fuel lffi adjustment valve (gas turbine equipment), 8...Combustor (gas turbine equipment), 10...Gas turbine (gas turbine equipment), 26...It generator output detector, 27. ...Pressure detector, 63... Plant control device, 64... Gasifier control section, 65... Gas turbine control section, 66...
Load control unit, 67... Pressure control unit, 70... Load setting device, 76... Pressure setting device, 84... Function generator,
85:...MII device, 86...Switcher (increase/decrease setting device)
.

Claims (1)

[Claims] Gasifier equipment that gasifies coal, gas turbine equipment that uses coal gas generated in this gasifier equipment as fuel, steam turbine equipment that uses heat from gas turbine exhaust gas, and power generation installed in each of the turbine equipment. and a plant control device that controls the gasification furnace equipment and the gas turbine equipment, the plant control device controlling the gas pressure based on the detected value of the gas pressure supplied from the gasification furnace. a pressure control unit that sets the gas pressure to a required value; a gas turbine control unit that controls the gas turbine equipment based on an output signal from the pressure control unit; and a gas turbine control unit that detects the output of the power generation system and requests the output. a gasifier controller that controls the gasifier equipment based on the output signal from the load controller, and a controller that inputs the deviation signal of the pressure controller as a reference signal. and a function generator that generates a control function by taking in the opening degree of the fuel flow rate regulating valve of the gas turbine equipment, and a function generator that generates a control function by taking in the opening degree of the fuel flow rate regulating valve of the gas turbine equipment, and a signal non-selection state of the gas turbine equipment from the pressure control unit in the gas turbine follow-up mode. The present invention is characterized by comprising a switch that takes in each output signal from the controller and the function generator when the switch is applied, and an increase/decrease setting device that increases or decreases the load setting value based on the output signal from the switch. coal gasification power plant.