JPH0323301A - 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 magnitude of a control deviation quantity in relation to the control set value of generated fuel gas pressure. 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 and pressure detectors 27, 28 for detecting inlet pressure of a fuel pressure adjusting valve 6 and a fuel flow rate adjusting valve 7, are provided. And in a plant control device 63 for inputting the output signals of respective detectors 26 to 28, when a gas turbine facility is not selected in gas turbine pressure control in a gas turbine following mode, pressure deviation bond out in a pressure control unit 67 is taken out by a changeover switch 80, so that a reduced load is set by a function generator 81 by making this deviation as a reference signal. A load setting value in a load controller 66 can be increased/ decreased by an increasing/decreasing setting device 82 on the basis of its output.

Description

[Detailed Description of the Invention] [Object of the Invention] (Utilization of Umanashi) The present invention relates to a coal gasification power plant, and in particular to a coal gasification power plant whose operation is stabilized by improving the plant υ1m equipment. II1'!j to the plant.

(Prior art) A coal gasification Rffi plant converts coal into gas fuel,
Make that gas! JJ A is a system that rotates a gas turbine and a compressor as a power source, as well as a generator, and is attracting attention because of its effective use of energy and its superiority in reducing pollution problems.

Among these power plants, coal gasification combined cycle power plants lead the exhaust heat of the gas turbine to the boiler, and generate steam obtained by heat exchange with the exhaust heat and steam obtained from the heat exchanger (cooler) of the gasifier. This system generates electricity by guiding the heat to a steam turbine, and has an 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 a gas purification system 15 via a gas cooler 4, where fuel gas is purified. The fuel gas is supplied to the fuel pressure regulating valve 6 and the fuel flow a.
The air is sent to the combustor 8 via the regulator 7, and is combusted by the air pressurized by the compressor 9. The gas turbine 10 is driven by this combustion gas, and the generator 11 generates electricity. Note that the air pressurized by the compressor 9 is transferred to the M motor 13.
The pressure is further increased by an interfacial pressure compressor 12 driven by
Oxidizer style! It is supplied to the i adjustment device 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 includes super heaters 16 . It has an evaporator 17 and an economizer 18, where the thermal energy of the exhaust gas is recovered, and these heat exchangers generate steam. 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 dehumidifier 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 gasifier 1, the coal pressure regulator 2, the oxidizer ffi regulator 3, etc. performs load control, and the combustor 8, compressor 9, gas turbine 10, and power generation 11.Gasta consisting of fuel pressure regulating valve 6, fuel flow regulating valve 7, etc. The pin equipment adjusts the gas turbine inlet gas pressure (or gas purification equipment inlet gas pressure) to υI.
t2ll1 mode.

Further, the gasifier follow-up mode is a mode in which the gas turbine equipment performs a load lIIIlI 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 in response to the required power generation (■), but since the gas pressure supplied from the gasifier 1 is accompanied by a large delay, 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 control 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 and tear, the gas turbine follow-up mode has an advantage.

In a coal gasification power plant, the temperature inside the gasifier is 1400℃.
Due to the high temperatures of ~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 knitting inside the furnace, can accelerate the wear and tear of the bricks. . 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, coal I1:l adjustment@2, and oxidizer adjustment device 3, a combustor 8, a compressor 9, a gas turbine 10, a power generator 11, and a fuel pressure A gas turbine installation consisting of a regulating valve 6 and a fuel flow ffi regulating valve 7 is shown.

R slaughter machine output detector 26 on the generator 11 of the gas turbine equipment
An inlet pressure detector 27 is provided on the upstream side of the fuel pressure all valve 6, and a fuel flow ffi adjustment valve 7 is provided.
An inlet pressure detector 28 is provided on the upstream side of the inlet pressure sensor 28 . Detection signals 101, 102, 103 from these ffill output detector 26 and each inlet pressure detector 27, 28 are as follows:
Each of these signals is input to a plant control system 29.

The plant i, IJ IA unit 29 has a gasifier control unit 30
, gas turbine It/I tll section 31, load control section 3
2 and pressure! , II control section 33.

In the load υ11I1 section 32, the load setting signal 104 is outputted from the load setting device 36 operated by the increasing operation device 34 or the decreasing operation device 35, and is input to the load change rate limiter 37. 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 101 of the generator output detector 26 input to the plant control device 29 are subtracted in the subtracter 38, and the obtained deviation signal 106 is sent to the proportional integral element 39. is input, and a proportional integral calculation is performed. The values after the proportional integral processing are input to the gasifier control unit 308 as the gasifier υIII] command signal 107, and based on this gasifier t, IJtllll command signal 107, the respective input times of coal and oxidizer are fblJ. m is calculated, and then the coal amount adjustment device [2's IJI1wJ command signal 1
08 and a control command signal 109 for the oxidizer suspension adjustment device 3.

On the other hand, in the pressure l1 control section 33, a pressure setting signal @110 is outputted from the pressure setting device 42 operated by the increasing operation device 40 or the decreasing operation device 41, and inputted to the pressure change rate limiter 43. In the pressure change rate υ1 limiter 43, the force 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, which is input to the plant control device 29, are subjected to reduction processing in the attenuator 44,
The deviation signal 112 obtained here is input to the proportional-integral element 45, and a proportional-integral calculation is performed.

The value after proportional integral processing is gas turbine it, IJ li
Gas turbine control rIFJW31 as t command message @113
After the fuel gas flow rate is calculated based on this gas turbine control IO command signal 113, it is output to the fuel flow rate regulating valve 7 as a control command signal 114.

Note that a signal 103 from the gas inlet pressure detector 28 of the fuel flow mgl regulating valve 7 is input to the gas turbine control section 31. A ν1m signal 115 is output to the fuel pressure regulating valve 6 based on the calculation result in the gas turbine control unit 31, and this control signal 115 causes the ffi fuel pressure regulating valve 6 to always keep the gas inlet pressure of the fuel flow regulating valve 7 constant. It is controlled so that the fuel is maintained at a constant temperature, and the fuel is suddenly cut off in the event of an abnormality.

With the above configuration of the plant control device 29, the gasifier equipment handles the load Rljtill, and the gas turbine equipment handles the pressure Rljtill. Since lJI is performed, it is possible to obtain the required load and to set the pressure within the gas system to a desired value.

(Problems to be Solved by the Invention) In recent years, with regard to the upper limit of the gas turbine inlet braid, there has been remarkable improvement in cooling technology for turbine blades, combustors, etc.
Gas turbines with a design point of around 1300 to 1400'C have come into practical use, and the development of ceramic turbine blades and combustors is progressing, so 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 that operates at a gas turbine inlet temperature of around 1300°C, thermal efficiency that is equal to or higher than that of a steam turbine can be obtained. There are also estimates that the increase in temperature at the gas turbine inlet is of particular interest.

However, as is well known in the art of gas turbine equipment, when the suction am 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, the increase in fuel must be limited to protect the gas turbine. It is provided in the word W 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 braid is at the rated point temperature. Therefore, when the atmospheric temperature rises, such as in the summer, the density of the air becomes lighter, and the volumetric outflow of air absorbed from the atmosphere by the gas turbine is constant, so the quality of the air fits! liEffl decreases. For this reason, if the gas turbine inlet temperature is operated at the design point temperature, the obtained R'R'll capacity 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 control unit 31
In order to obtain the rated point gas flow rate, the fuel flow control valve 7 is opened based on the signal from the pressure #AII1 section 33.
When the gas turbine inlet temperature reaches the rated point, an ilJ (not shown) is installed to prevent further fuel increase.
The limit MIII system limits the opening degree of the fuel flow control valve 7 to ensure safe operation of the gas turbine.

However, the υ1 limit Ill III operation in the gas turbine υ1lIl section 31 in a coal gasification power plant is as follows:
Control command signal 11 to gas turbine IJ lit section 31
3 means non-selection. That is, in the gas turbine follow-up mode, the generated gas pressure and in the gasifier follow-up mode, the generated power becomes -11111 non-selected. 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 these circumstances, and the Ill limit υI! of gas turbines has been developed. This provides a coal gasification power generation system that allows stable system operation without abnormal fluctuations in generated gas pressure even at 1:00 p.m.

[Structure of the invention]

(Means for solving the problem) Wood's invention is a gasifier M that gasifies coal! A cat, a gas turbine facility that uses coal gas generated in the gasifier facility as fuel, a steam turbine facility that uses heat from the gas turbine exhaust gas, a power generation system installed in each of the turbine facilities, and the gasifier facility. and a plant control system for controlling gas turbine equipment, the plant υIn device adjusts the gas pressure to a required value based on the detected value of the gas pressure supplied from the gasifier. The gas turbine equipment is controlled to υ+ based on the pressure lI11m to be set and the output signal from this pressure control unit.
a gas turbine control section that detects the output of the power generation system and sets the output to the requested output; Gasifier tII1l to control! 11 section, a switch that takes out a deviation signal at the pressure υJI1 section when the gas turbine equipment does not select the gas turbine pressure 6171111 under the gas turbine follow-up mode, and a switch for inputting this deviation signal as a reference signal and The present invention includes a function generator that sets a decreasing load according to the magnitude of the pressure deviation, and an increase/decrease setting device that increases or decreases the load setting value of the load setting section based on the output signal of the function generator. Features.

(Operation) According to the present invention, when the coal gasification power plant is operated in the gas turbine following mode, the gas turbine υ1
When the 611 part is in the υ1 limit III 611 state, the pressure deviation signal in the pressure control part is selected by the switch,
Based on the magnitude of the pressure deviation, a run pack (pullback) operation is performed on the load setting plate in the direction of increasing or decreasing.

Therefore, the load automatically operates to a value that provides the desired M gas pressure.

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

Note that coal gasification combined cycle power generation plans 1 to 1 to be controlled in this embodiment are the same as those shown in FIG. 2, so FIG. 2 will also be used as is for explanation of this embodiment.

The figure shows a gasifier equipment consisting of a gasifier 1, a coal reduction adjustment device 2, and an oxidizer amount adjustment device n3, a combustor 8, a compressor 1
19, gas turbine equipment consisting of a gas turbine 10, a power generation 11, a fuel pressure regulating valve 6, and a fuel flow regulating valve 7 is shown.

A generator output detector 26 is installed on the generator 11 of the gas turbine equipment.
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. Detection signals 201, 202, 203 from the generator output detector 26 and the inlet pressure detectors 27, 28 are respectively input to the plant control device [63].

The plant control system 1!63 includes a gasification fi control section 64, a gas turbine II m section 65, a load IIIK1 section 66, and a pressure IJ u section 67.

In the load control section 66, the increase operation device 68 or the decrease operation device 69
Load setting signal 2 from load setting device 70 operated by
04 is output and 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 201 of the generator output detector 26 input to the plant control device i163 are subtracted in the subtracter 72, and the obtained deviation signal 206
is input to the proportional-integral element 73, and a proportional-integral calculation is performed. The value after proportional integral processing is the gasifier tlIIWJ command signal 207. ! :L"lj is input to the gasification furnace 1110 section 64, and based on this gasification furnace υ11II command signal 207, the respective input amounts of coal and oxidizer are controlled and calculated, and then the υ1911 command signal 208 of the coal amount adjustment device 2 and is output as the υI'm command signal 209 of the oxidizer mram device 3.

On the other hand, in the pressure control unit 67 , a pressure setting signal 210 is outputted from a pressure setting device 76 operated by an increase operation device 74 or a decrease operation device 75 and inputted to a pressure change rate III limiter 77 . 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. Then, this output signal @211 and the output signal 202 from the inlet pressure detector 27 of the fuel pressure adjustment valve 6 inputted to the plant t, II all device 63 are subtracted in a subtractor 78. The obtained deviation signal 212 is input to the proportional-integral element 79, and a proportional-integral calculation is performed.

The value after proportional integral processing is the gas turbine control command signal @21
3 is input to the gas turbine control unit 65, and after the fuel gas flow rate is calculated based on this gas turbine III ill command signal 213, it is output to the fuel Fl flow rate regulating valve 7 as the υ1 command signal @214. .

Note that the signal 203 from the gas inlet pressure detector 28 of the fuel flow rate regulating valve 7 is input to the gas turbine control section 65.

A v+m signal 215 is output to the fuel pressure regulating valve 6 based on the performance result in the gas turbine control unit 65, and this IIJ
The fuel pressure regulating valve 6 is controlled by the m signal @215 to keep the gas inlet pressure of the fuel flow regulating valve 7 constant at all times, and to suddenly cut off the fuel in the event of an abnormality or the like.

In this device, a switching device 80. The function generator 81 and the subtractor 82 as an increase/decrease setting device are digitized by z2.

The switch 80 has a zero signal 216 or a pressure control section 67.
The output signal 212 from the subtracter 78 is input. In this switch 80, the input of the zero signal g216 is normally selected, but when the control signal 213 from the pressure control section 67 is in a non-selected state in the gas turbine 1, II Ill section 65, that is, when the input of the zero signal g216 is selected, When the gas turbine control unit 65 is controlled by the restriction control system and is operated in the gas turbine follow-up mode, from the zero signal 216,
The input is switched to the subtraction B7B output signal @212 of the pressure control section 67.

The output signal 217 from this switch 80 is input to the function generator 81 as a reference signal. In the function generator 81,
When the output signal 212 from the subtracter 78 of the pressure control section 67, which is a deviation signal, is input as the output signal 217, a reduced load is set according to the magnitude of the pressure deviation, and a reduced load signal @218 is output. Ru.

Then, the reduced load signal 2 outputted from the function generator 81
18 and a load! The load setter 70 output signal 204 of the tllllll section 66 is input to the subtracter 82, where a subtraction process is performed.

The output signal 219 from the subtracter 82 is then input to the load setter 70.

The load setter 70 performs a runback operation to increase or decrease the load setting value based on the output signal 219, so that the load automatically changes to a value that provides a desired fuel gas pressure.

According to such an embodiment, when the coal gasification power plant is operating in the gas turbine follow-up mode and the gas turbine t/J Il1 section enters the limited control state, the gas turbine control unit 65 disables the control. The selected pressure deviation signal @212 is turned off! ! ! It is sent to the pressure control section 67 in the container. Then, based on the magnitude of the pressure deviation of the signal 212, an optimum load is set so that a runback operation is performed in the direction of increasing or decreasing the load setting value. With this optimal load, the generated gas pressure is kept constant and the desired fuel gas pressure can be obtained.

Note that the restriction control of the gas turbine is not limited to the restriction control accompanying the rise in the gas turbine inlet temperature, but also the restriction control associated with the increase in the gas turbine inlet temperature.
Restriction lIII that makes the ill command value from the unit non-selectable
I can deal with everything.

(Effect of R Light) As described above, according to the coal gasification power plant according to the present invention, I
Since the load setting is increased or decreased depending on the magnitude of the Im deviation amount, in the gas turbine follow-up mode, the gas turbine inlet is Even in the case where the gas turbine enters the n state due to reaching the temperature limit control value, etc., the gas turbine can be safely operated within the limit value, and moreover, optimal load operation and pressure operation can be performed. Effects such as being made possible are achieved.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a flllall system showing an embodiment of a coal gasification power plant according to the present invention, and Fig. 2 shows the entire system of the coal gasification power plant. A family tree showing
FIG. 3 is a block diagram showing a conventional example. 1... Coal gasification furnace (gasification furnace equipment), 2... Coal adjustment device (gasification P equipment), 3... Oxidizer adjustment device GL? <Gasification P equipment), 7...Fuel flow adjustment valve (gas turbine equipment), 8...Combustor (gas turbine equipment), 10...Gas turbine (gas turbine equipment), 2
6... Generator output detector, 27... Pressure detector, 6
3... Plant control device, 64... Gasifier control section, 65... Gas turbine illtll section, 66...
Load control section, 67... Pressure control section, 70... Load setting device, 76... Pressure setting device, 80... Switching device, 81
...Function generator, 82...Subtractor (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 the output multiplication angle 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 an output signal from the load controller; and a gasifier controller that controls the gas turbine pressure in the gas turbine follow-up mode. a switch that takes out a deviation signal from the pressure control section when the pressure control section is not selected; a function generator that inputs this deviation signal as a reference signal and sets a reduced load according to the magnitude of the pressure deviation; A coal gasification power generation plant comprising: an increase/decrease setting device that increases or decreases a load setting value of the load setting section based on an output signal of a function generator.