JPS58119933A - Power-generation method and plant by gasified coal - Google Patents

Abstract

PURPOSE:To stabilize the flame in a combustor of a gas turbine at the time of load interception by previously accumulating auxiliary liquid fuel and supplying said fuel to the combustor at the time of the load interception. CONSTITUTION:The fuel gas supplied from a coal gasification furnace 2 is burned in a combustor 1, and a gas turbine 4 is driven by this burned gas. The power thereof is used to generate electricity by a generator 21. Auxiliary liquid fuel is accumulated in both of an accumulator 5 and a fuel tank 22. At the time of load interception, the auxiliary fuel is supplied from the accumulator 5 to a combustor 1 of a gas turbine 4 for stabilizing the flame in the combustor 1. Then, when a driving means for a pump or the like starts its operation, the auxiliary liquid fuel is supplied from the tank 22 instead of the accumulator 5.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coal gasification power generation method for generating power using coal gasification gas as fuel, and a coal gasification power generation plant used in the skeleton power generation method. In particular, it relates to a coal gasification power generation method and a power generation plant thereof, in which a gas turbine is driven by fuel gas supplied from a coal gasifier to generate power.

In this type of technology, many technical problems remain to be solved because the calorific value of the coal gasification gas used as fuel is low and the stability of combustion is poor. 4
First, during dumping when the flame has attenuated, there is a high possibility that the combustion gas will become unstable and cause a state in which it appears to be blown out.The solution to this problem is a superimposed technical challenge. Become.

That is, unlike coal gasification gas, the fuel gas mainly used in conventional gas turbines has a high calorific value and a wide stable combustion range. Therefore, the need for damping arises during normal operation;
Therefore, even when dumping to the maximum no-load state during rated load operation, it is possible to make the tank tank by simply reducing the fuel flow rate, and even in that state, the gas burns stably and the flame holding effect is reliable. ing.

However, in gas turbines using coal gasification power generation technology, the coal gasification gas fuel used as fuel contains few combustible components and is heavily diluted with nitrogen, so the calorific value is lower than that of conventional fuel. It is as low as about one-eighth, and the range of fuel-air ratios that allow stable combustion is also narrow. For this reason, when dumping, simply reducing the fuel flow by throttling it in the same way as in the past will result in an unstable combustion state midway through, making it impossible to maintain combustion and causing a new blowout. it is conceivable that.

However, despite the above-mentioned circumstances, no proposal has yet been made to solve the dumping problem in coal gasification power generation technology. Only a few techniques have been developed to stabilize the initial flame by using auxiliary fuel during ignition and start-up. Therefore, the present inventors focused on the problem during dumping, and based on the above-mentioned background, in coal gasification power generation technology, we have developed a technology to solve the above-mentioned problem by providing a new fuel control system different from the conventional one. The present invention was developed based on the belief that the need for development is urgent.

Furthermore, in fuel control during dumping of such a gas turbine, it is desirable that responsiveness be excellent. This is because if the responsiveness is poor, it may not be possible to respond quickly at the time of dumping, resulting in inconveniences such as the blowing out. This problem can be said to be particularly important in power generation using coal gasified gas, which has problems with combustion stability as described above.

In view of the above-mentioned circumstances, an object of the present invention is to provide an advantageous coal-based fuel that can be easily controlled during dumping of a gas turbine, does not cause blowout, and can be controlled with excellent responsiveness. An object of the present invention is to provide a gasification power generation method and a coal gasification power generation plant.

In order to achieve this objective, the present invention stores auxiliary liquid fuel in advance and supplies this auxiliary liquid fuel to the combustor of the gas turbine at the time of load interruption.
The structure is designed to stabilize the flame in the combustor during load shedding.

With such a configuration, if the gas turbine dumps,
The coal gasification gas supply line is cut off by the accompanying load cutoff signal, etc., and the line is quickly switched to supply the auxiliary liquid fuel described above, thereby making it possible to maintain a stable flame. Moreover, since the auxiliary liquid fuel can be stored in a way that allows quick response, it can be configured to respond instantly to load shedding without using a drive source with poor response such as a pump, resulting in a highly responsive system. can get things.

Furthermore, even if a drive source such as a pump is used, a storage fuel supply line that can respond quickly can be installed separately from the drive source, so that the delay time until the pump starts up can be satisfied. can.

The above configuration can be effectively applied to conventionally developed coal gasification power generation technology. In coal gasification power generation technology that has been developed in the past, liquid fuel with good combustion performance is used for auxiliary combustion during ignition and start-up of the gas turbine combustor. Therefore, if this liquid fuel supply line is used even during load shedding, and if a storm is modified so that auxiliary liquid fuel stored in a fuel tank or the like can be supplied from this line in advance, the present invention can be implemented with great ease. It can also be applied to the previous version.

In carrying out the present invention, it is possible to have a structure in which liquid fuel for load shedding is stored in advance in an achiemulator. When a load cutoff signal is received, the pressure of the gasifier can be used as the axillary liquid fuel O driving source. Alternatively, other pressure sources may be used, and these pressure sources and the opening/closing of valves installed in the lines, as well as pumps, can provide quick response to supply auxiliary liquid fuel to the combustor. It can be done.

If a mode is adopted in which both a line for supplying auxiliary liquid fuel from the fuel tank using a pump and a line for supplying auxiliary liquid fuel from the accumulator by a pressure source are adopted, auxiliary liquid fuel can be immediately supplied from the accumulator, After the pump starts up, fuel can be supplied from the fuel tank, which solves the problem of delay time until the pump starts up, and also makes it possible to save power.

An embodiment of the present invention will be explained below with reference to FIG. 1st
The figure shows a schematic diagram of the configuration of the coal gasification power plant of this example.

This power generation plant combusts fuel gas supplied from a coal gasifier 2 in a combustor 1, drives a gas turbine 4 with this combustion gas, and uses this power to generate electricity in a generator 21.

In the present invention, auxiliary liquid fuel is stored in advance, but in this example, the accumulator 5 and the fuel tank 22
Both are storing this. During load shedding, the accumulator PS or bM auxiliary liquid fuel is transferred to the gas turbine 4.
is supplied to the combustor 1 to stabilize the flame in the combustor 1 during load shedding. Next, when the driving means such as the pump starts up and reaches the 9th point, the tank 2 is replaced with the accumulator 5.
Auxiliary fuel supply starts from 2. In this example, accumulator 5
The auxiliary liquid fuel is supplied from the coal gasifier 2,
This is done by the pressure of the main fuel gas passing through the line 19.

More specifically, this embodiment has the following configuration.

During normal operation, combustor IK gasification fuel is supplied from the coal gasifier 2 through the fuel supply 2-in-8. This fuel flow rate is controlled by a flow control valve (CV-1) 7 on the line 8.

An air compressor 3 is provided, through which air is passed through an air line 18 and supplied to the combustor 1 for combustion of the fuel gas in the axillary combustor 1 and for dilution and Used for cooling. The combustion gas 20 after being combusted in the combustion chamber S1 rotates the turbine 4 and is discharged to the outside of the engine.

In this example, light oil is stored in the fuel tank 22 as liquid fuel for igniting and starting up the combustor. Therefore, in this embodiment, this light oil is also used as a fuel for load shedding. Tank 22 is also connected to storage accumulator 5 . Therefore, there is a system in which the light oil tank 22 passes through the pump 6, passes through the line 13 to the accumulator 5, and passes through the line 15 to the flow control valve (CV-2) 1.
There are two systems, one leading to the combustor 1 via 6. The system passing through the line 15 is also used to supply light oil fuel at the time of ignition and start-up, and in this example, the system is made to serve as a line for both the time of ignition and start-up and the time of load shedding.

From the accumulator 5 to the combustor 1, the line 11 passes through the bus stop valve (V-2) 9, the throttle valve 1o, and the combustor 1
It has become a twin. A method is adopted in which stop switching is performed from the gasifier.

On the other hand, the line 15 of the system that directly leads from the light oil tank 22 to the combustor 1 can be achieved by making the pressure in the line 15 higher by 1 than the pressure in the combustor 1. . During load shedding, as a result of the load reduction, combustion s
The pressure at i is reduced and therefore the fuel supply to the combustor 1 through this line is constant. If you only want to supply light oil to the combustor 1, you can continue to use only the 2-in IS, IT supply system via the accumulator 5, but if you use this twin 15, the 2-in IS, IT supply system via the accumulator 5 can be used, as will be detailed later. Compared to using .11, the power of the pump 6 is smaller, and power can be saved.

However, since this line 15 supplies auxiliary liquid fuel to the pump 6, there remains a problem in response.

If the purpose is simply to supply auxiliary liquid fuel to the combustor 1, it may be possible to avoid adopting a system such as the accumulator 5 in this example and use only this 2-in-15 system. But as mentioned above, line 15
Note that line 13.11, which has a problem with responsiveness, is also used. The response of Lie/15 using pump 6 can be summarized as follows.

Please refer to FIG. Now, via line 15, pump 6
The time point for feeding auxiliary fuel into the combustor 1 is designated as X. At time of ignition/startup or load cutoff, #
to obscure The pump 6 starts operating from time point X, but the pump pressure becomes sufficient at time point Y after a certain delay time. Therefore, at this point Y, the flow rate control valve 1 in 2-in 15
6 to send auxiliary fuel to the combustor IK. This is because unless the pump pressure reaches a certain level, supply cannot be achieved even if the valve 16 is opened. Therefore, when this twin 1st is used, it takes time for the pump to start up, and the response becomes poor. Therefore, it is not preferable for fuel supply during urgent load shedding. (Although it will be explained in detail later, line 13
．． In this embodiment, the twin 15 is supplied with fuel from the Akiemulator 5 at the same time, and the fuel supply may be started later.
At the same time, the twin 1s valve (V-2) 9 stops. That is, at point Y in Figure 4, where the pump 6 reaches a predetermined pressure, a command based on the cutoff signal 25 is issued to the flow control valve (CV-2) 16 with a time delay between XY and the valve 1 is turned off.
At the same time, the stop valve (V-2) 9 closes with the same command).

According to this embodiment, by setting the accumulator 5, it is possible to quickly achieve responsiveness when switching from the main gas fuel to the auxiliary liquid fuel such as light oil, and the above-mentioned pump It is possible to solve the problem of opening O when there is a delay in starting up. In addition, the pressure of the gasifier 2, the fuel volume of the accumulator 5, the pressure of the accumulator S, the diameter of the supply pipe, etc. are determined in advance so that a constant flow rate of auxiliary fuel is supplied to the combustor IK without causing blowout. Shibori (
In this example, if the throttle 10) shown in FIG. 1 is set, instantaneous and reliable flow control can be achieved by simply opening and closing a harmful valve. That is, adjustment using a flow rate control valve (such as valve 9 in Fig. 1) K is difficult to control and has problems in response, but the above setting eliminates the need for such valve control and is easy. It is capable of providing auxiliary fuel supply.

The power generation plant of this example also controls the flow rate of its own coal gasification gas using an ON-OFF sequence control method for valves and pumps. In addition, the flow rate control of light oil, which is auxiliary liquid fuel, is similar.
A lie/19 is provided which leads to the accumulator 5 via a valve 17, and by opening this valve 17, pressure for feeding the 1 light oil line IIK light oil is obtained from the gasifier 2.

That is, if the valve 17 is opened when auxiliary fuel is required,
Coal gasification gas is sent from the gasifier 2 to the accumulator 5, and the gas pressure thus provided provides auxiliary liquid fuel (light oil) from the accumulator 5 to the combustor IK via a line 11.

Next, a fuel operation and control method in this power plant will be explained using FIGS. 2 and 3.

First, the case of ignition and start-up will be described.

When igniting and starting up the combustor 1, the coal gasified fuel from the gasifier 2 is not used, but light oil (also used as auxiliary liquid fuel during load shedding) is used. Light oil is supplied into the combustor 1 from the fuel tank 22 by the pump 6 through the filter/15. Flow rate adjustment is done using 01N11 valve (CV-2) on line 1B.
) lec, as shown by the broken line in Fig. 2, when the machine load reaches about 5% (point A in Fig. 2), the light oil fuel decreases and instead, the coal gasification fuel shown by the concentrated line is supplied. This is connected to the gasifier 2 through the gasified fuel line 8 in Figure 1.
The flow rate is determined by the control valve (CV-1) 7 in the line 8. This valve 7
Puntrol is performed until the rated load at point jllE2IiiiIB is reached.

In this way, when igniting, light oil with a stable flame is used, and coal gasification gas is supplied while light oil is being supplied, so
The combustion of the gasified fuel, which is the main fuel, is carried out stably, and the start-up is completed.

This rise occurs when the stop valve (V
-1) Open 2 and store light oil in the accumulator 5. The light oil line 13 is provided with a check valve 14,
Even if the pump 6 is stopped, backflow is prevented. When the required amount of light oil is supplied to the accumulator 5 in this way, the stop valve ff-1) 12 is closed.

This concludes the explanation of the operation during ignition and start-up. Next, the operation during load shedding will be explained.

Consider a case where the load shedding signal 25 is issued from the generator 21 during normal operation. When the generator 21 issues a load shedding signal during normal operation, first the turbine 4
The generator 21 is cut off, and the load control device 24 receiving the load cutoff signal 25 outputs a command signal 25a to the flow rate control valve (CV-1) 7 of the gasification gas fuel supply line 8,
This valve (cv-i) 7 is immediately throttled. In other words, the load shedding signal 25 was issued at point 0 in FIG.
Immediately at this time, the coal gasified gas (indicated by a solid line in FIG. 2), which is the main fuel, is once throttled down to point E in the figure by the control of the valve 7. Thereafter, the wrinkle extension 7 is completely closed as shown in the figure, and the gas fuel supply is stopped.

Such main fuel control is to prevent the turbine 4 from overspeeding.

On the other hand, at the same time when the command signal 25m is output to the valve (CV-1) 7, the stop valve (V-2) 9 of the supply line 11 for the light oil fuel supplying the auxiliary liquid fuel and the accumulator 5 are connected at the 90th point. The stop valve (V-3) 17 of the pressure supply line 19 also receives a command signal 25b, respectively.
25c is output. This opens each valve 9, 17.

Therefore, the auxiliary fuel (light oil) in the accumulator 5 is instantaneously supplied to the S section IK. Gas pressure is applied from the gasifier 2 through the valve 17, and at the same time the valve 9 opens, so that the pressure causes the auxiliary fuel to flow through the wrinkle extension 9 to the light oil supply line/
Combustion I immediately after passing through 11! ! This is because IK is sent.

As shown in FIG. 2, at point 0, auxiliary liquid fuel (light oil) flows instantaneously and is supplied to the combustor 1.

It is assumed that the fuel flow rate is not adjusted by 4Ik, and the pressure of the gasifier 2 is used to feed auxiliary fuel (light oil) into the combustor IK. Further, a throttle 10 provided in the line 11 limits the maximum flow rate of fuel. This is the same as already mentioned.

Based on the cutoff signal 25, the load control device 24 also outputs a command signal 25d to the pump 6 at the same time. As a result, the pump 6 starts operating at time C as shown in FIG. While the above-mentioned auxiliary fuel is being supplied from the accumulator 5, the pump pressure reaches a predetermined pressure. This is point D in FIG. 3, and this point is also shown in FIG.

After the pump pressure reaches a predetermined value, the direct line 15 is used. This line 15 is connected to the ignition/rise-in 13 valve (
V-4) 12 is opened and the combustion l! Although it is possible to supply fuel to i+1, at this point the pressure in the accumulator 5 is already equal to the pressure in the gasifier 2, so in order to supply fuel to the accumulator 5, the pump 6 must be operated at a pressure higher than that pressure. The pressure must be increased to Therefore, in order to reduce this power, the ignition/start-up Kl! This is done by switching to the line 15 that was previously used. line 15
Since the line 15 is directly connected to the combustor 1, in order to supply fuel, the pressure in the line 15 must be raised above the pressure in the combustor 1, which has become low due to the reduced load. Therefore, the power of the pump 6 is increased due to power saving compared to using the supply system of lines 13 and 11.

At this time, the command signal 25e (first @
l) opens the flow control valve (CV-2) 16, and the line 15
Auxiliary fuel is supplied to the combustor 1. In other words,
Although the load control device 24 is based on the cutoff signal 25, it issues a command signal 25e with a time delay between the input time of the signal 25 and the CD of υ diagram, and sends this to the flow control valve (CV-
Output 2>16. At the same time, the same command signal is also output to the stop valve (V-2) 9, which closes and the fuel supply from the accumulator 5 via the twin 11 is stopped. This command signal 25e is also output to the valve (V-3) 17, the wrinkle extension 17 is closed, and the supply of driving gas from the gasifier is stopped. A time delay relay circuit 23 is used to generate a signal with a CD-related time delay.

With the above configuration, even when the load is cut off, the auxiliary fuel can be instantly sent to the combustor 1, combustion stability can be maintained, and blowout etc. can be reliably prevented. This is because the auxiliary liquid fuel stored in the accumulator 5 is directly supplied to the combustor 1. Therefore,
As described above, since there is no need to wait for the elapse of time until the pump 6 starts up, this is a perfect measure against load interruption.

In addition, in this embodiment, as the driving force for sending such stored auxiliary fuel (light oil in the accumulator 5) to the combustor 5, the gas pressure from the pressure source, particularly the coal gasifier 2, is used. Since the fuel cell is activated, instantaneous fuel supply can be reliably achieved, and the device is simple.

In addition, in this example, the throttle J) 1G is the pressure of the gasifier 2.

The fuel volume of the accumulator 5, the accumulator pressure, the diameter of the supply piping, etc. are properly set so that the light oil fuel flow is supplied to the combustor 1 at a constant flow rate so that the flame does not blow out. It's Nishide. Therefore,
Even without using a flow control valve that is particularly difficult to respond or control,
By simply opening and closing the valve, the flow rate of auxiliary fuel can be controlled instantaneously and with a high degree of reliability.

In this example, the flow rate control of gasified gas from the gasifier 2 of the power plant itself and the flow rate control of auxiliary fuel (light oil) are performed using a sequence control method of turning on and off various valves and pump 6. The control method is relatively simple and easy to operate and control.

Moreover, in this example, the power of the pump 6 is also used, and the pump 6
After the fuel is started up, the line 15 is used to directly supply fuel to the combustor 1 instead of the supply from the accumulator 5, which also has a power saving effect.

In the above-described embodiment, the pressure of the gasifier 2 is used as the drive source for supplying the stored auxiliary fuel, but other pressure sources may be provided.

For example, as schematically shown in FIG. 5, a compressed air storage tank 2' is provided in place of the line 190 in the example of FIG. The structure is such that it is fed into the container 1.

As mentioned above, in the coal gasification technology of the present invention, auxiliary liquid fuel is stored in advance, and at the time of load shedding, this auxiliary liquid fuel is supplied to the combustor of the gas turbine to suppress the flame in the combustor at the time of load shedding. Because of the stability, fuel control during dumping of the gas turbine is simple, and there is an effect that no blow-out occurs at that time. It is also advantageous in that it can be configured to perform control with excellent responsiveness.

Note that, as a matter of course, the present invention is not limited to the above-described embodiments.

[Brief explanation of drawings]

The first @ is a schematic diagram showing an embodiment of the coal gasification power plant of the present invention. Figures 2 and 3 are diagrams explaining the action of the chain and showing its control method. Figure 2 is a graph showing the relationship between each fuel and time, and Figure 3 shows the operation of each component. It is a diagram. FIG. 4 is a diagram illustrating the time delay for startup. swA is a schematic illustration of a modification of the above example. DESCRIPTION OF SYMBOLS 1...Combustor, 2...Coal gasifier, 4...Gas turbine, 5...Akiemulator, 6...Driving means (pump), 10...#? , 21... Generator, 2
2...Fuel tank. Agent: Patent Attorney Masami Akimoto No. 30

Claims (1)

[Claims] 1. In a coal gasification power generation method in which a gas turbine is driven by fuel gas supplied from a coal gasification furnace to generate electricity, auxiliary liquid fuel is stored in advance and a power source is used when the load is cut off. A coal gasification power generation method characterized by supplying auxiliary liquid fuel to the combustor of a gas turbine, thereby stabilizing the flame that flows into the combustor during load shedding. 2. The coal gasification power generation method according to claim 1, wherein the flow rate of the main fuel gas from the coal gasifier is reduced during load shedding. 3. The auxiliary liquid fuel is stored in a fuel tank and is delivered to the combustor by the driving means when the load is cut off.4. Coal gasification power generation method. 4. The coal according to claim 3, wherein the auxiliary liquid fuel supplied from the fuel tank to the combustor is sent through a twin that provides initial auxiliary fuel to the combustor at the time of ignition and start-up. Gasification power generation method. 5. A patent claim characterized in that the auxiliary liquid fuel is stored in an accumulator, and is supplied to the combustor by actuation by gas pressure from the coal gasifier or its own pressure source when the load is cut off. The coal gasification power generation method according to OmII Section 1 or 2. 6. The coal gasification power generation method according to claim 5, characterized in that the flow rate of the auxiliary liquid fuel supplied from the Akiemulator to the combustion aS is controlled by a throttle on the way. 7. Auxiliary liquid fuel is stored in the fuel tank and is round.
Claims characterized in that both the fuel stored in the Akiemulator is supplied with fuel, and the Akiemulator immediately supplies fuel when the load is cut off, and this is used to cover the delay time until the start of fuel supply from the fuel tank. 1st
The coal gasification power generation method according to item 1 or 2. 8. The coal gas according to claim 187, wherein the auxiliary liquid fuel supplied from the fuel tank to the combustor is sent through a line that supplies initial auxiliary fuel to the combustor at the time of ignition and start-up. Chemical power generation method. 9. The auxiliary liquid fuel stored in the accumulator is supplied to the combustor by actuation by gas pressure from the coal gasifier or other pressure source at the time of load cutoff. 7. ! Coal gasification power generation method according to Jt Take Item 8. 10. The coal gas according to any one of claims 7gL to 9, wherein the amount of the auxiliary liquid fuel supplied from the accumulator to the combustor is controlled by a throttling machine on the way. Chemical power generation method. 11. The auxiliary liquid fuel stored in the accumulator is supplied from the fuel tank, and in addition to the line from the nuclear fuel tank to the combustor via the accumulator, there is also a line that connects directly from the combustion tank to the combustor. Coal gasification power generation according to any one of claims 7 to 10, characterized in that the power for supplying fuel from the fuel tank to the combustor after the operation of the storage accumulator is reduced. Method. 12. Claim 18iS that the auxiliary liquid fuel is light oil
The coal gasification power generation method according to any one of Items 1 to 11. 13. In a coal gasifier power plant equipped with a coal gasifier and a gas turbine that is driven by fuel gas supplied from the coal gasifier to generate electricity, auxiliary liquid fuel is placed in advance in a fuel tank and an accumulator. Save it up,
At the time of load shedding, the auxiliary liquid fuel is immediately supplied from the Akiemulator to the combustor of the turbine, and the delay time between fuel supply from the fuel tank #1 is used for this, and with this configuration, the auxiliary liquid fuel is immediately supplied to the combustor of the turbine at the time of load shedding. A coal gasification power generation plant characterized by a stable flame. 14. Claim 1s13, characterized in that the flow rate of the main fuel gas from the coal gasifier is reduced during load shedding.
Coal gasification power plant described in paragraph. 15. Claim 13 or 14, characterized in that the auxiliary liquid fuel supplied from the fuel tank to the combustor is sent through a line that supplies initial auxiliary fuel to the combustor at the time of ignition and start-up. Coal gasification power plant described in. 16. The auxiliary liquid fuel stored in the accumulator is such that when the load is cut off, the gas pressure i9 from the coal gasifier is supplied to the combustor by operation by another pressure source. Range 13th to 1st
The coal gasification power plant according to item 5. 17. The coal according to any one of claims 13 to 16, wherein the amount of the auxiliary liquid fuel supplied from the accumulator to the combustor is controlled by a throttling machine on the way. Gasification power generator. 18. The auxiliary liquid fuel stored in the accumulator is supplied from a fuel tank, and in addition to a line leading from the fuel tank to the combustor via the accumulator, a twin line is provided that directly connects the combustion tank to the combustor, The coal gasification power plant according to any one of claims 13 to 17, characterized in that this reduces the power required to supply fuel from the fuel tank to the combustor after the accumulator is activated. . 19.Claim 13 that the auxiliary liquid fuel is light oil
The coal gasification power plant according to any one of items 1 to 18 O.