JP2000345174A - Coal gasification type power plant and its operation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coal gasification type power plant operated by gasifying coal with oxygen or oxygen-enriched air produced by using an oxygen production device and then using the produced gas as a fuel to rotate a gas turbine, capable of corresponding to the change of load. SOLUTION: This coal gasification type power plant is operated by using the extracted air of a gas turbine compressor to produce oxygen or oxygen- enriched air from an oxygen-producing device, using the oxygen or the oxygen- enriched air as an oxidizing agent to gasify coal, and then using the produced gas as a fuel to operate a gas turbine for the generation of power. Therein, when the load to the plant is raised, the extracted air from the gas turbine compressor is directly supplied to the gasification oven to improve the load followingness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has an oxygen production apparatus, partially oxidizes coal using oxygen or oxygen-enriched air as an oxidizing agent, and uses a gas turbine as a fuel with the obtained coal gasified gas as fuel. To a power plant.

[0002]

2. Description of the Related Art A plant which partially oxidizes coal and uses a gas turbine as a fuel to generate electricity using a gas turbine as a fuel, has an oxygen producing apparatus, and a plant which uses oxygen as an oxidizing agent for coal gasification. However, compared to a plant that uses air as the oxidant, the high temperature required for coal gasification can be easily obtained, so the amount of power generated by oxygen utilization increases more than the decrease in power generated by oxygen production. It is an efficient system.

When the amount of power generation is changed in accordance with a load command in the integrated coal gasification combined cycle power plant having this oxygen production apparatus, the load following characteristic of oxygen production becomes a problem. This is a device where oxygen production equipment separates oxygen and nitrogen from air,
This is because it is difficult to rapidly change the processing speed.
For example, when a distillation method is used for producing oxygen, distillation uses the difference between the boiling points of oxygen and nitrogen. Therefore, a large heat exchanger is indispensable because it is necessary to first reduce the temperature of normal-temperature air to -190 ° C. Further, as shown in the theory of vapor-liquid equilibrium, the distillation step must be repeated a plurality of times in order to obtain high-purity oxygen due to the limitation of the separation efficiency of oxygen and nitrogen.

[0004] In order to improve the load following performance of a coal gasification power plant using such an oxygen production apparatus, efforts have been made to improve the load followability of the oxygen production apparatus itself and to optimize the system configuration of the entire coal gasification power plant. This improves load followability.

[0005] First, as a method of improving the load following capability of the oxygen production apparatus itself, there is known a method of providing a buffer tank in a cool tank outside the rectification column (Japanese Patent Application Laid-Open No. Hei 6-313674). However, this method not only requires a buffer tank, but also requires an increase in the capacity of the cooling tank.

As a method of improving the load following ability by changing the system configuration of the entire integrated coal gasification combined cycle power plant,
A method for installing an oxygen storage tank (JP-A-63-57825) is known. In this method, when the oxygen storage tank is installed outside the cold storage tank of the oxygen production apparatus, the efficiency is significantly reduced, and when installed inside the cold storage tank, the cost increases.

[0007] A method is also known in which the oxygen producing apparatus is always operated at the maximum load and the amount of air is adjusted according to the load ratio of the coal gasifier (Japanese Patent Laid-Open No. 57-207690). In this method, the load followability is improved and the capacity of the oxygen production apparatus is reduced, but the proportion of oxygen in the oxidant under the maximum load state of the coal gasifier becomes lower than the value giving the maximum efficiency. Therefore, this known example is not practical in terms of efficiency.

[0008] As described above, there is a problem in the method of performing the load variation operation according to the load command in the coal gasification plant having the oxygen production apparatus according to the prior art.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide an oxygen production apparatus having a low load following performance in a plant that partially oxidizes coal and uses the obtained coal gasification gas as a fuel to generate power using a gas turbine. Has oxygen as an oxidant,
Alternatively, even in the case of using oxygen-enriched air, an object is to make it possible to change the power generation amount according to a load command.

[0010]

SUMMARY OF THE INVENTION A first embodiment of the present invention is directed to an oxygen producing apparatus for producing oxygen or oxygen-enriched air using air as a raw material, and an oxygen or oxygen-enriched air produced by the oxygen producing apparatus. A coal gasifier for gasifying coal with air as an oxidizing agent, and a gas turbine power generator for generating power using gas generated in the coal gasifier as fuel, and a gas turbine compressor in the gas turbine power generator In the coal gasification power plant in which bleed air is introduced into a gas turbine combustor, the oxygen production device and the coal gasifier, the bleed air from the gas turbine compressor when the load of the gas turbine power device increases. The configuration is such that air is introduced into the coal gasifier by bypassing the oxygen production apparatus.

In the present invention, the control for calculating the flow rate of the extracted air introduced into the coal gasifier by bypassing the oxygen generator based on the load command and the states of the oxygen generator and the coal gasifier. Preferably, it comprises a device.

Further, a flow control valve is provided on a line for introducing bleed air from the gas turbine compressor into the coal gasifier by bypassing the oxygen production apparatus, and the flow control valve is controlled based on a command from the control apparatus. Preferably, the opening is adjusted.

Another embodiment of the present invention is directed to an oxygen production apparatus for producing oxygen or oxygen-enriched air from air as a raw material, and coal using oxygen or oxygen-enriched air produced by the oxygen production apparatus as an oxidizing agent. A gasification coal gasifier, and a gas turbine power generator for generating electricity using the gas generated by the coal gasifier as fuel, and using gas turbine combustion in the gas turbine power generator to extract air from a gas turbine compressor. A method for operating a coal gasification power plant, which is adapted to be introduced into a gas generator and the oxygen production device and the coal gasification furnace, wherein when the load of the gas turbine power generation device rises, the extracted air from the gas turbine compressor is extracted. The oxygen production system is bypassed and introduced as an oxidizer for the coal gasifier.

As one type of coal gasifier, there is a type in which a coal supply port and an oxidant supply port are provided in two upper and lower stages.
In this type of coal gasifier, coal is usually evenly distributed to upper and lower feed ports. On the other hand, the oxidizing agent is added more to the lower supply port. This is because the lower part of the furnace is kept at a high temperature so that the slag tap of the gasification furnace is not blocked. Naturally, there is an appropriate ratio of oxygen and coal to convert coal into gas. The amount of the oxidizing agent supplied to the upper stage is controlled so as to maintain this proper ratio. In the present invention, bleed air from the gas turbine compressor can be introduced into one or both of the two upper and lower oxidant supply ports. However, if the load change speed is fast, the bleed air from the gas turbine compressor is introduced into the lower oxidant supply port of the gasifier, and if the load change speed is slow, the upper oxidant supply port is used. It is desirable to introduce bleed air from the gas turbine compressor.

When the load reaches the target state, the supply of the bleed air from the gas turbine compressor to the coal gasifier is stopped, and the supply of the bleed air to the oxygen production apparatus is stopped.

An oxygen producing apparatus for producing oxygen or oxygen-enriched air using air as a raw material, a coal gasifier for gasifying coal using the oxygen or oxygen-enriched air produced by the oxygen producing apparatus as an oxidizing agent, One of the construction methods of a coal gasification power generation plant including a gas turbine power generation device that generates power using gas generated by the coal gasification furnace as fuel is to extract air extracted from a gas turbine compressor of the gas turbine power generation device. There is a system to introduce into an oxygen production device and a coal gasifier. This method is disclosed in JP-A-10-226791 and JP-A-58-80381. According to the present invention, in a plant of this type, a bypass line for directly introducing the bleed air from the gas turbine compressor to the coal gasifier without supplying it to the oxygen production apparatus is provided, and the load from the gas turbine compressor is increased when the load increases. Part of the bleed air is introduced into the coal gasifier through this bypass line. In addition, a flow control valve is installed in the bypass line, and a control device that calculates a flow rate of the bleed air flowing through the bypass line based on a load command and a state of the coal gasifier is provided. The flow rate of the bleed air flowing through the bypass line is controlled based on the above command.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment 1) First, the configuration of an integrated coal gasification combined cycle power plant according to the present invention will be described with reference to FIG. This system is largely composed of a coal supply unit 100, an oxygen production unit 200, a coal gasification unit 300, and a gas purification unit 40.
0, a power generation unit 500. The coal 1 supplied from the coal supply unit 100 and the oxidant (oxygen or oxygen-enriched air) 2 supplied from the oxygen production apparatus 200 are reacted in the coal gasification unit 300, and the produced hydrogen and carbon monoxide are the main components. This is a system in which a coal gasification gas 6 is dedusted and desulfurized in a gas purification unit 400 and power is generated in a power generation unit 500 using the purified gas 7 as fuel. In the present embodiment, a method of driving the steam turbine 520 using exhaust heat of the gas turbine as well as the gas turbine 513 in the power generation unit is shown, but the power generation unit may be configured using only the gas turbine.

Next, details of each section will be described. The coal supply unit 100 includes a coal bunker 101, a mill 102, and a lock hopper 103. The coal bunker 101 is a facility for storing coal. The mill 102 supplies coal to, for example, 100
This is a device that crushes to 90% mesh under to remove coarse viscous matter. The lock hopper 103 is a device for pressurizing the pulverized coal with nitrogen 5 which is a by-product from the oxygen production device 200 and supplying the pressurized coal to a gasifier burner.

The oxygen producing apparatus 200 is an apparatus that cools the extracted air 4 extracted from the gas turbine compressor 511 and fractionates nitrogen and oxygen in the air by using a difference in boiling point. The oxygen supply valve 93 is a valve for controlling the supply amount of oxygen as an oxidant or oxygen-enriched air in accordance with the operation state of the system.

The coal gasifier 300 includes a coal gasifier 31.
0, a heat recovery unit 320. Coal gasifier 31
0 is a lower burner 3 for supplying coal 1 and oxidizer 2
11, an upper burner 312, a heat recovery section 320 for cooling a reaction gas, and a slag water cooling tank 330 for collecting slag generated by melting coal ash. The solidified slag is discharged by the line 11.

The gas purifier 400 comprises a cyclone 410, a dust filter 420, a desulfurizer 430, and a gas-gas heat exchanger 440. The cyclone 410 and the dust filter 420 are devices for collecting solid fine particles in the coal gasification gas, and the desulfurization device 430 is a device for removing hydrogen sulfide in the reaction gas. Either may be used. Examples of the wet desulfurization method include a chemical absorption method using an absorbent such as methyldiethanolamine as a desulfurizing agent, and a physical absorption method using an absorbent such as Celexol. A dry desulfurization method in which hydrogen sulfide is directly fixed by fine particles of calcium carbonate or zinc oxide can also be used.

The power generation section 500 includes a gas turbine compressor 51
1, combustor 512, gas turbine 513, waste heat recovery boiler 530, steam turbine 520, condenser 550, generator 5
40, and performs combined power generation (combined cycle power generation). The gas turbine compressor 511 pressurizes the air 3 to generate compressed air, and the combustor 512 combusts the purified coal gasified gas containing hydrogen and carbon monoxide as the main component. Drives the gas turbine 513 to rotate the generator 540. Here, the amount of air supplied to the gas turbine compressor is determined by the inlet guide vane 5
14 to control. The exhaust heat recovery boiler 530 converts heat energy from the exhaust gas 8 of the gas turbine 513 into steam 10
It is a device to collect in the form of. This heat recovery steam generator 53
0 from the steam 10 obtained from the steam turbine 520.
To rotate the generator 540. The steam 10 that has driven the steam turbine 520 is returned to the liquid 12 by the condenser 550, and is supplied to the exhaust heat recovery boiler 530 and the gasifier heat recovery unit 320. Reference numeral 9 indicates cooling water, and reference numerals 201 and 202 indicate compressors.

In the plant shown in FIG. 1, when the load increases, the gas turbine compressor 5 is supplied to the coal gasifier 310 with the oxygen or oxygen-enriched air produced by the oxygen producing apparatus 200.
The bleed air 4 from 11 is added and supplied. For this,
As shown in FIG. 1, a bypass line 20 for supplying bleed air from the gas turbine compressor 511 to the coal gasifier 310, a flow control valve 91 for controlling the amount of bypass air supplied through the bypass line, a bleed air A compressor 203 for pressurizing air is provided. The compressor 203 is necessary to introduce the extracted air extracted from the gas turbine compressor into the gasification furnace. In FIG. 1, oxygen or oxygen-enriched air from the oxygen production apparatus and bleed gas from the gas turbine compressor are mixed by the mixer 21 and supplied to both the upper burner and the lower burner. Alternatively, only oxygen or oxygen-enriched air may be supplied to one of the lower stages and the other. This method will be described in Examples 3 to 5.

(Embodiment 2) In this embodiment, an operation method of the coal gasification power plant shown in FIG. 1 will be described. Roughly, the load command 31 and the state quantity 30 of the plant are input to the control value calculation function unit 40 of the control unit 50, and the gas turbine bleed air amount 71, which is supplied to the gasification furnace 310 bypassing the oxygen production apparatus 200. The gas turbine extraction air amount 72 supplied to the oxygen production device, the oxygen amount or oxygen-enriched air amount 73 supplied from the oxygen production device to the gasifier, and the air amount 74 supplied to the gas turbine compressor are calculated. , The flow control valve 91, the air supply valve 92, the oxygen or oxygen-enriched air supply valve 93, and the inlet guide vane 514 are controlled by the controllers 61 to 64, respectively. The state quantity of the plant is specifically the state quantity of the oxygen production apparatus and the state quantity of the coal gasifier.

The details of the control unit are shown in FIG. First, a control method of the flow control valve 91 will be described. From the load command 31, the amount of oxygen required by the gasifier is calculated. On the other hand, the supply amount of oxygen or oxygen-enriched air and the oxygen concentration at the outlet of the oxygen production device are actually measured to calculate the actual supply amount of oxygen by the oxygen production device. From the difference between the required oxygen amount and the actual oxygen supply amount, a gas turbine bleed air amount (by-pass air amount in the figure) to be supplied to the gasifier by bypassing the oxygen production apparatus is calculated. Here, when air is supplied to the gasification furnace, the gasification furnace temperature is lower than in the case where high-purity oxygen is supplied, because about four times as much nitrogen as oxygen exists in the air. Therefore, for example, the temperature in the furnace and the slag flowing down state are actually measured as the gasification furnace state, and correction for increasing the bypass air amount is performed. The target value of the bypass air amount obtained as described above is
To control the flow rate control valve 91. Here, the controller measures the measured value of the bypass air amount, and is a device that controls the valve opening by a proportional integral control method using a deviation between the measured value and a target value.

The air supply valve 92 calculates the amount of air required in the oxygen production apparatus from the load command, inputs a target value of the air supply amount to the controller 62, and controls the air supply valve. Here, the controller measures the measured value of the bypass air amount, and is a device that controls the valve opening by a proportional integral control method using a deviation between the measured value and a target value.

Next, a control method of the oxygen or oxygen-enriched air supply valve 93 will be described. First, the amount of oxygen required by the gasifier is calculated from the load command. Here, since the load following capability of the oxygen production device is low, if the calculated oxygen amount is extracted from the oxygen production device, the pressure of the oxygen production device may drop sharply. Thus, for example, pressure, temperature, etc. are used as the state of the oxygen production apparatus, and the calculated oxygen amount is corrected to make the oxygen amount within a range not exceeding the restrictions of the oxygen production apparatus. This value is input to the controller 63 as a target value,
Control the oxygen supply or oxygen-enriched air valve. Here, the controller 63 is a device that actually measures the oxygen supply amount and controls the valve opening by a proportional-integral control method using a deviation between the measured value and a target value.

The inlet guide vane 514 sums the amount of air required by the gas turbine (GT), the amount of bypass air supplied to the gasifier by bypassing the oxygen production device, and the amount of air supplied to the oxygen production device. This value is input to the controller 64 to control the inlet guide vane.

(Embodiment 3) This embodiment shows a method of supplying air extracted from a gas turbine compressor to a gasification furnace. First, the device configuration will be described with reference to FIG. The bypass line 20 that supplies the extracted air 4 extracted from the gas turbine compressor to the gasification furnace without passing through the oxygen production apparatus 200 is provided with a shutoff valve 95, a flow control valve 91, a compressor 203, and a shutoff in order from the upstream side. A valve 96 is installed, and a bypass line is a shutoff valve 98 for supplying oxygen to the upper stage of the gasification furnace.
Is connected to a mixer 21 downstream of the mixer.

Next, the operation method of these devices will be described. If a load increase command is input at a load change rate at which oxygen deficiency may occur, the shutoff valve 9 on the bypass line
5, 96 is opened and the compressor 203 is started. The bypass flow rate is controlled by the flow rate control valve 91 based on a command from the control device. Here, the rotation speed of the compressor 203 is controlled in accordance with the bypass flow rate.

(Embodiment 4) In this embodiment, another system for supplying air extracted from a gas turbine compressor to a gasifier is shown. First, the device configuration will be described with reference to FIG. A bypass line 20 that supplies the extracted air 4 extracted from the gas turbine compressor to the gasification furnace without passing the extracted air 4 through the oxygen production apparatus 200.
Is provided with a shut-off valve 95, a bypass flow control valve 91, a compressor 203, and a shut-off valve 96 in this order from the upstream side. It is connected to a certain mixer 21.

Next, a method of operating these devices will be described. If a load increase command is input at a load change rate at which oxygen deficiency may occur, the shutoff valve 9 on the bypass line
Open 5,96 and start the compressor. The bypass flow rate is controlled by the flow rate control valve 91 based on a command from the control device. Here, the rotation speed of the compressor 203 is controlled in accordance with the bypass flow rate.

[0033]

According to the present invention, a plant for partially oxidizing coal and generating electricity by using a gas turbine using the obtained coal gasified gas as fuel is provided with an oxygen producing apparatus having low load following performance, Even if oxygen or oxygen-enriched air is used, the power generation amount can be changed according to the load command.

[Brief description of the drawings]

FIG. 1 is a diagram showing one embodiment of a coal gasification power generation plant of the present invention.

FIG. 2 is a diagram showing an embodiment of a method for operating a coal gasification power plant according to the present invention.

FIG. 3 is a diagram showing one embodiment of a bypass line configuration of the coal gasification power generation plant of the present invention.

FIG. 4 is a diagram showing another embodiment of the bypass line configuration of the coal gasification power generation plant of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Coal, 2 ... Oxidizing agent, 4 ... Bleed air, 6 ... Coal gasification gas, 20 ... Bypass line, 30 ... Plant state quantity, 31 ... Load command, 40 ... Control value calculation function unit, 50 ...
Control unit, 61 to 64 controllers, 100: Coal supply unit, 200: Oxygen production device, 203: Compressor, 300:
Coal gasifier, 310: coal gasifier, 311: lower burner, 312: upper burner, 400: gas purifier, 50
0: power generation unit, 511: gas turbine compressor, 513: gas turbine, 520: steam turbine, 540: power generator.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Toru Akiyama 7-1-1, Omikacho, Hitachi City, Ibaraki Prefecture Inside Hitachi Research Laboratory, Hitachi, Ltd. (72) Inventor Atsushi Morihara 7-1 Omikacho, Hitachi City, Ibaraki Prefecture No. 1 F Term in Hitachi Research Laboratory, Hitachi, Ltd. (Reference) 3G081 BA02 BA13 BB00 BC07 BD00 DA21

Claims (6)

[Claims] 1. An oxygen production apparatus for producing oxygen or oxygen-enriched air using air as a raw material, and a coal gasifier for gasifying coal using the oxygen or oxygen-enriched air produced by the oxygen production apparatus as an oxidizing agent. And a gas turbine power generator for generating electricity using the gas generated in the coal gasifier as fuel, wherein the bleed air from the gas turbine compressor in the gas turbine power generator is a gas turbine combustor, the oxygen generator and In the coal gasification power generation plant adapted to be introduced into the coal gasification furnace, when the load of the gas turbine power generation device rises, the bleed air from the gas turbine compressor bypasses the oxygen production device and performs the coal gasification. A coal gasification power generation plant characterized by being configured to be introduced into a furnace. 2. The method according to claim 1, wherein when the load is increased, the oxygen gas is bypassed into the coal gasifier based on a load command and the state of the oxygen gas generator and the coal gasifier. A coal gasification power plant comprising a control device for calculating a flow rate of extracted bleed air. 3. A flow control valve according to claim 2, wherein a line for introducing bleed air from the gas turbine compressor to the coal gasifier by bypassing the oxygen production device is provided,
A coal gasification power plant, wherein an opening of the flow control valve is adjusted based on a command from the control device. 4. The coal gasifier according to claim 1, wherein the coal gasifier has a coal supply port and an oxidant supply port in two upper and lower stages, respectively, and bleed air from the gas turbine compressor is used for the oxygen production apparatus. A coal gasification power plant, wherein the coal gasification furnace is bypassed and introduced into an oxidant supply port at an upper stage of the coal gasification furnace. 5. The coal gasifier according to claim 1, wherein the coal gasifier has a coal supply port and an oxidant supply port in upper and lower two stages, respectively, and bleed air from the gas turbine compressor is used for the oxygen production apparatus. A coal gasification power generation plant characterized in that it is bypassed and introduced into an oxidant supply port at a lower stage of the coal gasification furnace. 6. An oxygen production apparatus for producing oxygen or oxygen-enriched air using air as a raw material, and a coal gasifier for gasifying coal using the oxygen or oxygen-enriched air produced by the oxygen production apparatus as an oxidizing agent. And a gas turbine power generator for generating electricity using the gas generated in the coal gasifier as a fuel, and extracting air extracted from a gas turbine compressor in the gas turbine power generator with a gas turbine combustor, the oxygen producing apparatus, and A method of operating a coal gasification power plant that is adapted to be introduced into the coal gasification furnace, wherein when the load of the gas turbine power generation device is increased, bleed air from the gas turbine compressor bypasses the oxygen production device. A method for operating a coal gasification power plant, wherein the method is introduced as an oxidizing agent for the coal gasification furnace.