JP2002061517A - Power generating plant and its operating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure combustion stability of a gas turbine to burn hydrocarbon fuel and to reduce an NOx exhaust amount. SOLUTION: A generating plant 1 comprises a gas turbine combustor 3 to burn hydrocarbon fuel 2; a fuel feed part 4 to feed the hydrocarbon fuel 2 to the gas turbine combustor 3; a gas turbine 6 driven by combustion gas 5 of the gas turbine combustor 3; and a generator 7 coupled to the gas turbine 6 and outputting a power. A fuel reforming device 10 is provided to be constituted that at least a part 2a of the hydrocarbon fuel 2 is reformed to hydrogen and carbon monoxide through pyrolytic reaction utilizing heat obtained from the generating plant 1 or reaction using a catalyst and a hydrogen content of hydrocarbon fuels 2b and 2c fed to the gas turbine combustor 3 is set to 1-10 vol.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a power plant and an operating method thereof. More specifically, the present invention relates to a gas turbine combustor for burning a hydrocarbon-based fuel (LNG, kerosene, light oil or a mixture thereof), a gas turbine driven by the combustion gas, and a gas turbine coupled to the gas turbine. And a method of operating the same.

[0002]

2. Description of the Related Art As a thermal NOx reduction technique implemented in a gas turbine combustor used in this type of power plant, water or steam is mixed with fuel air passing through an air swirler provided in a burner. A technique for lowering the temperature of combustion gas is known.

[0003] Further, there is known a technique (lean premixed combustion method) in which a hydrocarbon-based fuel is premixed with combustion air and supplied so as to uniformly reduce the combustion gas temperature and suppress thermal NOx. . In this combustion method, in order to maintain the gas temperature in the burner above a certain level for the purpose of flame holding, a bypass valve is installed in the transition piece, and the supply amount and supply position of combustion air are changed according to the gas turbine load. A technique of keeping the equivalence ratio near the burner high or a technique of changing the burner according to the load of using the fuel nozzle as a multi-burner method is adopted.

[0004]

However, even if an attempt is made to lower the temperature of the flame by mixing water or steam, in the case of diffusion combustion, it is not possible to completely suppress the occurrence of a local high-temperature region. NOx will be generated.

Moreover, in the case of hydrocarbon fuels, the combustible range is originally narrow and combustion stability is not good, so that it is difficult to devise NOx reduction measures such as increasing the excess air ratio or employing the partial combustion method. Have a problem.
Therefore, even in a gas turbine combustor using a lean premixed combustion method, which is considered to be suitable for reducing NOx, since combustion stability is poor, it is necessary to mix fuel and air in advance in a completely uniform state. In many cases, a pilot flame of diffusion combustion is used partly, or a fuel-rich region is created in a part of the fuel as a kind of fire, and there is a problem that NOx is generated therefrom. In particular, in gas turbine power plants using hydrocarbon fuels, the thermal efficiency of the plant has been improved by raising the working gas temperature.However, as the temperature rises in the future, a lean premixed combustion method is typical. Conventional combustion technology, the current N
It is expected that maintaining Ox emission levels will be difficult.
For this reason, in a power plant using a gas turbine, development of a low NOx combustion technology having excellent combustion stability has become an important issue.

Accordingly, an object of the present invention is to provide a power plant and a power plant operating method which are excellent in combustion stability in a power plant using a gas turbine and can reduce NOx emissions.

[0007]

In order to achieve the above object, the present invention is directed to a gas turbine combustor for burning a hydrocarbon fuel, and a gas turbine driven by the combustion gas of the gas turbine combustor. And a generator coupled to the gas turbine and driven to output power, wherein at least a portion of the hydrocarbon-based fuel uses a pyrolysis reaction or a catalyst utilizing heat obtained from the power plant. And a fuel reforming device that reforms hydrogen and carbon monoxide by the reaction to supply the hydrocarbon-based fuel supplied to the gas turbine combustor with a hydrogen content of 1 to 10 vol%. Further, according to the present invention, the gas turbine is driven by the combustion gas obtained by burning the hydrocarbon-based fuel in the gas turbine combustor, and the electric power is generated by rotating the generator coupled to the gas turbine. In a power plant operating method that outputs hydrogen, at least a portion of the hydrocarbon fuel is reformed into hydrogen and carbon monoxide using heat obtained from the power plant to reduce the hydrogen content of the hydrocarbon fuel to 1 to 10 vol%. And burn it with a gas turbine.

[0008] Hydrogen slightly increases the fuel-lean flammability limit as compared with hydrocarbon-based fuel, but has a high fuel speed.
It is a fuel that has a small ignition energy and a small quenching distance and is highly flammable. In addition, if the amount is very small, the combustion rate is not increased more than necessary and there is no danger of flashback. Therefore, the presence of hydrogen having a wide flammable range increases the combustion stability and facilitates flame holding. Thereby, a more complete lean premixed combustion method can be applied. Moreover, its hydrogen content is sufficient to increase combustion stability, and
ol%, the cost for reforming with the heat obtained from the power plant is reduced. Further, since the temperature of the hydrocarbon-based fuel is increased by the reforming, the combustion stability is increased as compared with the conventional case where the reforming is not performed. Therefore, when trying to obtain combustion gas at the same temperature, it is possible to reduce the fuel and increase the air ratio, so that it is possible to realize more lean combustion and reduce the amount of NOx generated.

Further, since the hydrogen content is a very small amount of about 1 to 10 vol%, the oxygen component or water (steam) required for reforming is smaller than when reforming the whole or most of the hydrocarbon fuel. The amount of heat and reforming catalyst can be reduced to a small amount, and the equipment for supplying the oxygen component or steam can be simplified to reduce the cost. In addition, since the hydrogen content is about 1 to 10 vol%, 9
It does not require a high temperature of 00 to 1000 ° C.
Since the temperature can be suppressed to about 0 ° C., the reforming can be performed using an inexpensive low-temperature catalyst, and the waste heat from the power plant that has dropped to about 400 ° C. can be effectively used. . Therefore, the power generation cost can be reduced. Further, depending on the conditions, hydrocarbons are sufficiently thermally decomposed into hydrogen and carbon monoxide even at 500 to 600 ° C., and in that case, a reforming catalyst is not necessary. On the other hand, depending on the conditions, hydrocarbons are thermally decomposed even without an oxygen component or moisture by controlling the reaction with an appropriate catalyst, and in that case, equipment for supplying the oxygen component or moisture is not required.

[0010] Here, when the hydrogen content is less than 1 vol%, the combustion amount of hydrogen is insufficient and the combustion stability is not improved. When the hydrogen content exceeds 10 vol%, more hydrogen than necessary is obtained. Thus, equipment and cost for obtaining a large amount and high temperature of oxygen or steam for reforming are wasted. Therefore, since it is desired to suppress the hydrogen content to the minimum, if the hydrogen content is 1 vol% or more and 10 vol% or less, preferably 2-3 vol%, the equipment and cost required for reforming are minimized. The combustion stability and the reduction of the NOx emission can be simultaneously realized while keeping the limit.

According to a second aspect of the present invention, in the power plant according to the first aspect, the hydrocarbon fuel is partially reformed to reduce the hydrogen content of the hydrocarbon fuel to 1 to 10 vol.
1%. In this case, since the reforming rate is extremely low, the reforming can be performed by utilizing the low heat obtained from the power plant using the low-temperature catalyst, for example, the exhaust heat from the gas turbine that has been reduced to about 400 ° C. It is not necessary to provide a heat source for reforming.

According to a third aspect of the present invention, in the power plant according to the first aspect, a part of the hydrocarbon-based fuel is entirely reformed and mixed with a non-reformed hydrocarbon-based fuel. The hydrocarbon fuel is supplied to the gas turbine combustor after the hydrogen content of the fuel is reduced to 1 to 10 vol%. In this case, since the flow rate of the hydrocarbon-based fuel to be processed by the fuel reformer can be minimized, the size of the fuel reformer can be suppressed and the cost required for reforming can be suppressed.

According to a fourth aspect of the present invention, in the power plant according to the first aspect, a part of the hydrocarbon-based fuel is reformed, and the hydrocarbon-based fuel is not reformed in a different system from the non-reformed hydrocarbon-based fuel. The fuel nozzle supplies the gas turbine combustor. In this case, a hydrocarbon-based fuel containing carbon monoxide and hydrogen is supplied to a pilot burner for flame holding by reforming, and a stable fuel lean and flame is always formed, thereby ensuring combustion stability.

According to a fifth aspect of the present invention, the gas turbine combustor of the power plant according to the first aspect is configured such that a hydrocarbon-based fuel and combustion air are premixed and then supplied to a combustion chamber. . In this case, a lean premixture containing a small amount of hydrogen having a wide flammable range is generated, so that the combustion stability is improved without preparing a premixture having a rich portion of the fuel. Therefore, there is no danger of inversion, and the mixture of fuel and air can be made more uniform to achieve a more complete lean combustion.

Here, the heat for the reforming is the heat obtained from the power plant, for example, the exhaust gas of the gas turbine or the gas turbine combustor, the transition piece of the gas turbine combustor, etc. Preferably, it is obtained from any one or more of the turbine blades of the gas turbine. In this case, the reforming can be performed by effectively utilizing the heat obtained from the power plant, and the reforming cost can be reduced. In particular, when heat is obtained from the transition piece or turbine blade of a gas turbine, the cooling performance of the turbine blade can be improved, and when heat is further obtained from the turbine blade, the air of the compressor is used to cool the turbine blade. So you do n’t have to
Plant thermal efficiency can be improved.

According to a seventh aspect of the present invention, there is provided the power plant according to any one of the first to sixth aspects, wherein unburned hydrocarbon components or carbon monoxide components in the gas discharged from the gas turbine combustor. Monitor the component concentration,
Monitoring and control means is provided for controlling the reforming rate of the hydrocarbon-based fuel such that the concentration of the unburned component such as the hydrocarbon component or the carbon monoxide component becomes a predetermined value or less. According to a ninth aspect of the present invention, in the power plant operating method according to the eighth aspect, the concentration of an unburned component such as a hydrocarbon component or a carbon monoxide component in the gas discharged from the gas turbine combustor is monitored, The reforming rate of the hydrocarbon fuel is controlled so that the concentration of the unburned component such as the hydrocarbon component or the carbon monoxide component becomes equal to or lower than a predetermined value.
In these cases, combustion stability can be improved while suppressing the concentration of unburned components such as hydrocarbon components or carbon monoxide components to a predetermined value or less.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below in detail based on an example of an embodiment shown in the drawings. FIG. 1 shows an embodiment of a power plant 1 according to the present invention. The power plant 1 includes a gas turbine combustor 3 for burning a hydrocarbon fuel 2, a fuel supply unit 4 for supplying the hydrocarbon fuel 2 to the gas turbine combustor 3, and a combustion gas of the gas turbine combustor 3. 5 and a generator 7 coupled to the gas turbine 6 and driven to output electric power.

The power plant 1 includes an oxygen supply device 9 for supplying steam 8 for reforming the hydrocarbon fuel 2 supplied from the fuel supply unit 4 to the gas turbine combustor 3, And a fuel reforming apparatus 10 that reforms a part of the hydrocarbon-based fuel 2 in which the hydrogen-containing fuel 2 is mixed to make the hydrogen content of the hydrocarbon-based fuel 2 supplied to the gas turbine combustor 3 1 to 10 vol%. are doing. In the fuel reformer 10, at least a part of the hydrocarbon-based fuel 2 mixed with the steam 8 is reformed into hydrogen and carbon monoxide by a reaction using a catalyst using the exhaust heat of the power plant 1. I am trying to do it. For this reason, the hydrocarbon-based fuel 2 supplied to the gas turbine combustor 3 contains a small amount of hydrogen of about 1 to 10 vol%, and the hydrocarbon-based fuel 2 supplied to the gas turbine combustor 3 is discharged as heat. Can be heated by
As compared with the case where the reforming is not performed, the combustion stability can be improved and the NOx emission can be reduced. Here, the hydrogen content is about 1 to 10 vol%, preferably 2 to 10 vol%.
It is a trace amount of ３3 vol%. In this case, a small amount of steam 8 required for reforming is required as compared with the case where most of the hydrocarbon fuel 2 is reformed, and the cost required for supplying steam 8 can be reduced. , At 400 ° C. or at a relatively low temperature of 500 to 600 ° C., or by a reaction using a catalyst.

According to our experiments, 100% CH ₄ fuel was reformed to about 1.0 vol%, CH ₄ = 97.06 vol%, CO = 0.98 vol%, H
₂ = 1.96 vol% (actually, in the experiment, the H ₂ / CO volume ratio was fixed at 2.33, so that CH ₄ = 98.37 vol%, CO = 0.
49Vol%, when the H ₂ = a 1.14vol%), not discharged most unburnt hydrocarbons, to obtain a finding that flame stability is much better. Therefore, if hydrogen is contained in an amount of 2 to 3 vol%, the combustion stability is sufficient, and the cost for reforming can be reduced.

FIG. 7 shows the results of a combustion test of a mixed gas of CH ₄ , CO and H ₂ . Although the concentration of unburned components in the exhaust gas shifts depending on the burner and the experimental conditions, it can be generally said that the following tendency can be said. Conditions are: Fuel composition: mixed gas of CH ₄ , CO, and H ₂ . However, the H ₂ / CO volume ratio is constant at 2.33. -Combustion temperature = 1500 ° C (constant)-Air / fuel preheat temperature = 400 ° C / 230 ° C-Composition example: component Experimental point on drawing, from left end → CH ₄ = 100.00% 98.37% 96.67% 93.34% H ₂ = 0.00% 1.14% 2.33% 4.66% CO = 0.00% 0.49% 1.00% 2.00% In this experiment, the experimental conditions were set so that the difference in fuel composition could be seen as much as possible. When concentration of H ₂ is 0% (CO concentration 0%, C
H ₄ concentration 100%) of what is unburned hydrocarbon concentration in the exhaust gas was about 15ppm is, H ₂ concentration 1.14% (CO concentration 0.49%, CH ₄ concentration 9
8.37%), the unburned hydrocarbon concentration dropped to 1.7 ppm. Further, when the concentration of H ₂ reaches the 2.33 to 4.66%,
The unburned hydrocarbon concentration was almost saturated with 1.2 to 0.8 ppm (including measurement error). In other words, LNG (here, CH ₄ = 100% substitute)
The, CH ₄ = 99% by decomposition 1%, CO = 1%, ( when the entire averaging and _{100%, CH 4 = 97.06%} , CO = 0.98%, H 2 = 1.96%) H 2 = 2% in Then, the concentration of unburned hydrocarbons in the exhaust gas
It was found that it could be reduced from 15 ppm to 1.2 ppm.

In this embodiment, a part 2 of the hydrocarbon fuel 2 supplied from the fuel supply unit 4 to the gas turbine combustor 3
and a dividing means 11 for taking out a. The oxygen supply device 9 supplies the steam 8 to a part of the hydrocarbon fuel 2a taken out by the flow dividing means 11. Then, a part of the hydrocarbon fuel 2a divided by the dividing means 11 is reformed into the reformed gas 2c by the fuel reformer 10, and is premixed with the unreformed hydrocarbon fuel 2b. The gas is supplied to the gas turbine combustor 3.
Here, the fuel reformer 10 sets the hydrogen content in the hydrocarbon-based fuel supplied to the gas turbine combustor 3 to 1 to 1
The reformed gas 2c is generated so as to be 0 vol%. That is, the hydrogen content in the total hydrocarbon fuel including the fuel 2c reformed by the fuel reformer 10 and the unreformed hydrocarbon fuel 2b directly sent to the gas turbine combustor 3. Is reformed in the fuel reforming apparatus 10 to the extent that the pressure becomes 1 to 10 vol%. Therefore, the fuel reformer 1
Since the flow rate of the hydrocarbon fuel 2a to be treated at 0 can be minimized, the size of the fuel reformer 10 can be suppressed and the cost required for reforming can be suppressed.

The fuel reformer 10 includes a catalyst for reforming a part or all of the hydrocarbon fuel 2a diverted by using the steam 8 to hydrogen and carbon monoxide. In the fuel reforming apparatus 10, since it is sufficient to perform reforming so as to have a minute hydrogen content of about 1 to 10 vol%, a low-temperature catalyst that reacts at about 400 ° C. and exhaust heat from a power plant are used as a catalyst. This enables reforming. Further, depending on the conditions, hydrocarbons are sufficiently thermally decomposed into hydrogen and carbon monoxide even at 500 to 600 ° C., and in this case, the fuel reformer 10 does not require a catalyst and can be operated at lower cost. On the other hand, depending on the conditions, hydrocarbons are thermally decomposed even without an oxygen component by controlling the reaction with a suitable catalyst, and in that case, equipment for supplying an oxygen component or moisture is not required, and In some cases, it can be operated at a lower cost than when a reformer does not require a catalyst with an oxygen supply device.

Here, the fuel reforming apparatus 10 is connected to the exhaust port of the gas turbine 6, and uses the heat of the exhaust gas 12 of the gas turbine 6 as a heat source for the reforming action.

In the power plant 1, the concentration of unburned components such as hydrocarbon components or carbon monoxide components in the combustion gas discharged from the gas turbine combustor 3 is determined by using the gas 12 after work in the gas turbine 6. A monitoring control means for continuously monitoring and controlling a reforming ratio of the hydrocarbon fuel so that the concentration of the unburned component such as the hydrocarbon component or the carbon monoxide component becomes equal to or lower than a predetermined value; I have. In this embodiment,
Flow control valves 14 and 15 are provided between the flow dividing means 11 and the gas turbine combustor 3 and between the flow dividing means 11 and the fuel reformer 10, respectively. And monitoring control means 1
Reference numeral 3 controls the reforming rate of the hydrocarbon-based fuel 2 by controlling the flow control valves 14 and 15.
Therefore, the gas turbine combustor 3 can maintain the unburned component concentration such as the hydrocarbon component or the carbon monoxide component at a predetermined value or less.
Combustion stability can be improved.

The gas to be monitored is the exhaust gas 12 from the gas turbine 6 in this embodiment. Thus, the concentration of unburned components such as hydrocarbon components or carbon monoxide components can be monitored. However, the gas to be monitored is not limited to this, and the combustion gas 5 immediately after being discharged from the gas turbine combustor 3 may be monitored. Also in this case, the concentration of unburned components such as hydrocarbon components or carbon monoxide components can be monitored.

As shown in FIG. 2, the gas turbine combustor 3 includes an inner cylinder 17 forming a combustion chamber 16, and an outer cylinder covering the inner cylinder 17 and forming a combustion air flow path around the inner cylinder 17. 18
A plurality of fuel injection nozzles 22 penetrating the outer cylinder 18 to inject the fuel 2b, 2c into a flow path / space between the outer cylinder 18 and the inner cylinder 17, and a primary fuel formed at the top of the combustor Nozzle 1
9, a secondary fuel nozzle 25 opened along the circumferential direction on the peripheral surface of the inner cylinder 17, the fuel 2b, 2c injected from the fuel injection nozzle 22, and the combustion air 24 to mix the premixed gas. The premix combustor 37 includes a premix duct 38 for supplying the fuel nozzles 19 and 25 to the fuel nozzles 19 and 25. For this reason, the fuels 2 b and 2 c injected from the fuel injection nozzle 22 are supplied to the premixing duct 38 by the combustion air 2.
4 and is mixed into a premixed gas 37 and then injected into the combustion chamber 16 at two positions. That is, a part of the premixed gas 37 is injected into the combustion chamber 16 while swirling through the swirler 21 of the primary fuel nozzle 19 to form a flame 27. The remainder of the premixed gas 37 is supplied from the secondary fuel nozzle 25 to the combustion chamber 1.
6 and is burned. Thus, it is possible to stably maintain the lean premixed combustion and prevent the generation of a local high temperature region by injecting the premixed gas at two positions, thereby suppressing the generation of NOx. Further, by installing the fuel injection nozzle 22 on the downstream side of the secondary fuel nozzle with respect to the combustion air 24, the premixing in which the fuel is injected into the combustion chamber 16 while swirling through the swirler 21 of the primary fuel nozzle 19. The fuel concentration in the gas can be increased, and a more stable flame can be formed.

The primary fuel nozzle 19 is provided with a starting fuel nozzle 20 to which the starting fuel 23 or the reformed gas 2c is supplied. After the start, the flame can be held by the reformed gas 2c. A transition piece 26 is attached to the inner cylinder 17 to guide the combustion gas 5 to the gas turbine 6.

The power plant 1 further includes a compressor 28 for sending compressed air as combustion air 24 to the gas turbine combustor 3 and a steam 30 using exhaust heat of the exhaust gas 29 from the fuel reformer 10. Waste heat recovery boiler 3 to be generated
1 and a steam turbine plant 32 that generates electric power using steam 30 generated by the exhaust heat recovery boiler 31. The steam turbine plant 32 includes a steam turbine 33 driven by steam 30 from an exhaust heat recovery boiler 31,
The steam turbine 33 includes a generator 34 for generating electric power using the power obtained by the steam turbine 33 and a condenser 35. Further, the exhaust gas 29 after the heat exchange in the exhaust heat recovery boiler 31 is discharged from the chimney 36 to the atmosphere. The exhaust heat recovery boiler 31, the steam turbine plant 32, the gas turbine combustor 3, the fuel supply unit 4, the gas turbine 6,
Since neither the generator 7 nor the compressor 28 itself is a feature of the present invention, an existing one or a new one can be used.

An operation method of the power plant 1 configured as described above will be described below.

When the power plant 1 is started, the starting fuel 23 is injected from the starting fuel nozzle 20 and the combustion air 24 from the compressor 28 driven by external power is supplied from the swirler 21 of the primary fuel nozzle 19. Blow out. Then, as shown in FIG. 3, after the gas turbine 6 reaches the no-load rated rotation speed by the combustion using the starting fuel injected from the starting fuel nozzle 20, the generator 7 is inserted and the load is gradually increased. To increase power generation and reduce gas turbine load by 2
When it reaches about 5%, the fuel is switched while keeping the gas turbine load constant. That is, the flow control valves 14 and 15
Is released, steam 8 is added to a part of the fuel 2a and supplied to the fuel reforming apparatus 10 to gradually switch to a premixed gas of the partially reformed fuel and combustion air. Also, in the operation using the start-up fuel 23, the hydrocarbon-based fuel 2 or the start-up fuel 23 can be partially reformed to contain hydrogen in the fuel depending on the conditions. Operation with fuel can be stably performed.

In the fuel reformer 10, the catalyst is heated by exhaust heat of the exhaust gas 12 from the gas turbine 6. Therefore, the hydrocarbon of the fuel 2a reacts with the mixed steam 8 by a catalytic action to be reformed into hydrogen and carbon monoxide. A part of the reformed fuel 2c is a non-reformed fuel 2b
And the fuel injection nozzle 22 of the gas turbine combustor 3
The remaining fuel 2 c after reforming is supplied to the starting fuel nozzle 20. Then, while the start-up fuel 23 is being throttled, the pre-mixed gas 37 of the fuels 2b and 2c and the combustion air 24 is gradually switched.

Here, even if the combustion mode is switched to the combustion with the premixed gas 37, the operation of low load is performed for a while, so that the temperature of the flame 27 decreases. While monitoring the concentration of unburned components such as components, control is performed so as to keep the reforming ratio of the fuel 2 high. That is, the combustion stability is enhanced by increasing the amount of hydrogen contained in the premixed gas 37. And the gas turbine 6
Since the flame temperature increases as the load increases, the monitoring control means 13 controls so that the reforming rate of the fuel 2 is gradually reduced to lower the hydrogen content.

By operating in this manner, hydrogen fuel 2d (fuel in which reformed fuel 2c and unreformed fuel 2b are premixed) having a wider flammable range than hydrocarbon fuel 2 can be used.
Since the concentration in 2c can be appropriately controlled according to the concentration of unburned components such as hydrocarbon components or carbon monoxide components in the exhaust gas 12, that is, the temperature of the flame 27, and the temperature of the premixed gas 37 can be increased. In addition, it is possible to improve the combustion stability and suppress the emission of unburned components, and it is possible to reduce the amount of generated NOx.

When the switching of the fuel is completed, the load on the gas turbine 6 is gradually increased to increase the power generation.

On the other hand, the exhaust heat recovery boiler 31 is provided with an exhaust gas 29 that has been working with the gas turbine 6 and the fuel reformer 10.
Is exchanged with the water of the steam turbine plant 32 to generate steam 30. The steam 30 obtained by the exhaust heat recovery boiler 31 is supplied to a steam turbine 33 to rotate it. After the steam turbine 33 reaches the no-load rated speed,
The generator 34 is inserted and the load is gradually started to increase the power generation. Steam 3 after work in steam turbine 33
0 is condensed by the condenser 35 and is returned to the waste heat recovery boiler 31 again.
Supplied to

The above embodiment is an example of a preferred embodiment of the present invention, but the present invention is not limited thereto, and various modifications can be made without departing from the gist of the present invention. For example, in the present embodiment, the monitoring control unit 13 that monitors the combustion gas 5 or the exhaust gas 12 from the gas turbine 6 and controls the reforming ratio is provided, but the monitoring control unit 13 may not be provided in some cases. . For example, in the case of a simple power plant 1 that does not need to strictly control the reforming rate of the hydrocarbon fuel 2, the facility can be simplified without providing the monitoring control means 13.

Further, in the above-described embodiment, a part of the hydrocarbon-based fuel is diverted, almost all of it is reformed, and then mixed with the remaining unreformed hydrocarbon-based fuel to obtain 1 to 10 V
The fuel is supplied as a fuel having a hydrogen content of 1% to 10% by supplying all the fuel 2 to the fuel reformer 10 and partially reforming it.
A fuel having a hydrogen content of 1% may be obtained. In this case, the amount of the steam 8 and the reforming temperature are adjusted so that the fuel reformer 10 partially reforms the entire amount of the fuel 2. In this case, since the reforming conditions are milder than the full reforming, it can be decomposed at a reaction temperature of about 400 ° C. as in a pre-reformer, so that the reforming process can be stably operated and equipment such as a fuel supply path can be simplified. Can be

Further, in the above-described embodiment, the heat required for the catalytic action in the fuel reformer 10 is obtained from the exhaust gas 12 of the gas turbine 6. However, the present invention is not particularly limited thereto. As shown, it may be obtained from the gas turbine combustor 3. The fuel reforming apparatus 10 in this case is configured to be installed in the premixing duct 38 of the gas turbine combustor 3 or around the transition piece 26 as shown in FIG. 5, or to extract heat therefrom. Is also good. For example, when the fuel reformer 10 is installed in the premixing duct 38, the fuel 2 previously mixed with the steam 8 is supplied to the fuel injection nozzle 22. Thereby, the premix duct 38
The fuel 2 is reformed in the fuel reformer 10 using the heat of the fuel, and is converted into a reformed gas containing hydrogen and injected into the combustion chamber 16.

Around the transition piece 26, the fuel reformer 10
When the fuel reformer 10 is installed, the fuel 2 previously mixed with the steam 8 is supplied to the fuel reformer 10, and the fuel 2 is reformed by the heat of the transition piece 26 in the fuel reformer 10 to obtain the reformed gas 2c. it can. The reformed gas 2c is supplied to the gas turbine combustor 3 and burned. In this case, by installing the fuel reformer 10 around the transition piece 26, the transition piece 2
6 can be improved in cooling performance.

Further, the fuel reforming catalyst itself is directly incorporated in the gas turbine combustor 3, the premix duct 38, the transition piece 26, the turbine blades, etc., and a part of the gas turbine combustor 3 and the like is reformed. Alternatively, the exhaust heat obtained therefrom may be taken out and taken out of the fuel reformer 10.
May be given.

In addition, the amount of the hydrocarbon is 500 to 500, depending on the conditions.
Even at 600 ° C., the fuel is sufficiently thermally decomposed into hydrogen and carbon monoxide. In this case, the fuel reformer 10 does not require a catalyst and can be operated at a lower cost. Also in this case, since it is necessary to keep the temperature conditions, gas conditions (LNG, oxygen content, etc.) and the reaction time constant, it is preferable that a vessel or region called a reformer exists.

In the power plant 1 shown in FIG. 4, devices other than the gas turbine combustor 3, for example, the gas turbine 6, the generator 7, the steam turbine plant 32 and the like are the same as those in the embodiment shown in FIG. Therefore, the description is omitted. In the power plant 1 shown in FIG. 4, the monitoring control means 13 and the flow control valves 14 and 15 are not shown.
It is preferable to provide these. The monitoring control means 13 is installed so as to monitor the exhaust gas 12 from the gas turbine 6, and the flow control valves 14 and 15 are connected to the fuel gas 2.
Is installed so as to control the supply amount to the gas turbine combustor 3 and the fuel reformer 10. This makes it possible to optimally control the reforming rate of the hydrocarbon fuel 2 to be burned.

In each of the above embodiments, the heat required for the catalysis in the fuel reformer 10 is obtained from the exhaust gas 12 from the gas turbine 6 or from the gas turbine combustor 3. However, the present invention is not limited to this. As shown in FIG. 6, the fuel reformer 10 is provided inside the turbine
Heat may be obtained from the turbine blade. In this case, the fuel 2 previously mixed with the steam 8 is supplied to the fuel reformer 10.
By supplying a, the reformed gas 2c can be obtained by utilizing the heat of the turbine blade. This reformed gas 2c is supplied to the gas turbine combustor 3. According to this, since it is not necessary to use the air of the compressor 28 for cooling the turbine blades, the thermal efficiency of the plant can be improved.

In the power plant 1 shown in FIG. 6, devices other than the gas turbine 6, for example, the gas turbine combustor 3, the generator 7, the steam power plant 1, and the like are the same as those in the embodiment shown in FIG. Therefore, the description is omitted. Although the monitoring control means 13 and the flow control valves 14 and 15 are not shown in the power plant 1 shown in FIG.
It is preferable to provide them in the same manner as in the embodiment shown in FIG. 1 to optimally control the reforming ratio of the hydrocarbon-based fuel 2.

Further, in each of the above-described embodiments, steam 8 is provided for reforming the hydrocarbon fuel 2. However, the present invention is not limited to this. You may do it. At this time, depending on the conditions, the reforming temperature is, for example, about 500 ° C. for methane, the decomposition is started, and almost 1000% (95%)
Is decomposed into hydrogen and carbon monoxide. By controlling the temperature in accordance with the degree of reforming, the hydrogen content of the fuel can be reformed to 1 to 10 vol%.

In this embodiment, the lean premixed combustion is mainly described, but the present invention can also be applied to diffusion combustion. Also in this case, the flame holding becomes easy due to the presence of a small amount of hydrogen due to the reforming, so that it is possible to devise measures for reducing NOx, for example, to apply the partial combustion method and to increase the air ratio.

[0047]

As is clear from the above description, according to the power plant according to the first aspect, the power plant according to the eighth aspect, and the method of operating the same, hydrogen having a wide flammable range due to fuel reforming is converted to hydrocarbon-based hydrogen. Since about 1 to 10 vol% is contained in the fuel, the combustion stability of the hydrocarbon-based fuel is increased, and the flame is easily held. For this reason, it is easy to devise measures for reducing NOx. For example, in the case of the lean premixed combustion as in the invention of claim 5, since the combustion stability is improved by the presence of hydrogen having a wide flammable range, the mixture of the fuel and the air by the premixing creates a fuel rich portion. And the temperature can be made even closer to complete lean combustion, and the effect of reducing NOx due to the reduction of the local high-temperature region by uniform combustion can be obtained. Also, in the case of diffusion combustion, since flame holding is easy, the degree of freedom of air distribution schemes for reducing NOx, for example, concentration combustion, is increased, and NOx can be further reduced. In addition, since the hydrocarbon fuel can be heated by heat from the power plant during reforming, the temperature of the premixed gas or the mixed gas can be increased to further improve the combustion stability and to obtain the same combustion temperature. In this case, the fuel can be reduced and the air ratio can be increased, so that a further fuel-lean state can be realized, and the NOx emission can be reduced.

Further, since the hydrogen content is about 1 to 10 vol%, the amount of oxygen component or water required for reforming can be reduced to a small amount as compared with the case where most of the hydrocarbon fuel is reformed. And the size of the equipment can be reduced.

[0049] According to the power plant of the second aspect, the hydrocarbon-based fuel is partially reformed to obtain 1 to 10 vol.
Since the hydrogen content is about 1%, the reforming rate is extremely low, so that low heat obtained from a power plant using a low-temperature catalyst is used, for example, exhaust heat from a gas turbine reduced to about 400 ° C. Thus, there is no need to particularly provide a heat source for the reforming. For this reason,
The reforming cost is reduced. Therefore, the power generation cost can be reduced.

According to the power plant of the third aspect, the flow rate of the hydrocarbon fuel to be processed by the fuel reformer can be minimized. Required cost can be kept low.

According to the fourth aspect of the present invention, a part of the hydrocarbon-based fuel is reformed, and the remaining hydrocarbon-based fuel which has not been reformed is used as a fuel substantially consisting of carbon monoxide and hydrogen. Because of the combustion, stable combustion becomes possible.

According to the fifth aspect of the present invention, a lean premixture containing hydrogen having a wide flammable range is generated.
Since the combustion stability is improved without producing a premixed gas having a rich portion of fuel, the mixture of fuel and air can be made more uniform and closer to complete lean combustion. Therefore, generation of NOx can be reduced.

Further, according to the invention of claim 6, reforming can be performed by effectively utilizing heat obtained from the power plant, and the reforming cost can be reduced. In particular, when obtaining heat from the transition piece or turbine blade of a gas turbine,
These cooling performances can be improved, and when heat is to be obtained from the turbine blades, it is not necessary to use compressor air for cooling the turbine blades, so that the plant thermal efficiency can be improved.

Further, according to the power plant according to the seventh aspect and the power plant operating method according to the ninth aspect, the concentration of unburned components such as hydrocarbon components or carbon monoxide components can be suppressed to a predetermined value or less. Thus, the combustion stability can be further improved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a power plant according to the present invention.

FIG. 2 is a longitudinal sectional side view showing a gas turbine combustor.

FIG. 3 is a graph showing a change in a fuel reforming amount when the power plant is started.

FIG. 4 is a schematic diagram showing another embodiment of the power plant.

FIG. 5 is a longitudinal sectional side view showing another embodiment of the gas turbine combustor.

FIG. 6 is a schematic diagram showing another embodiment of the power plant.

FIG. 7 is a graph showing the results of an experiment on the effect of hydrogen concentration in fuel on unburned hydrocarbon concentration in exhaust gas.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Power generation plant 2 Hydrocarbon fuel 2a Hydrocarbon fuel supplied to a fuel reformer 2b Hydrocarbon fuel supplied directly to a gas turbine combustor without being reformed 2c Reformed hydrocarbon fuel 2d Fuel premixed with unreformed fuel and reformed fuel 3 Gas turbine combustor 4 Fuel supply unit 5 Combustion gas 6 Gas turbine 7 Generator 8 Steam 9 Steam supply device 10 Fuel reformer 12 Gas turbine exhaust gas 13 Monitoring Control means 26 transition piece

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02C 7/22 F02C 7/22 A 9/00 9/00 B 9/40 9/40 A F23R 3/30 F23R 3/30

Claims (9)

[Claims] 1. A gas turbine combustor for burning a hydrocarbon fuel, a gas turbine driven by combustion gas of the gas turbine combustor, and a generator coupled to the gas turbine and driven to output electric power. Wherein at least a portion of the hydrocarbon-based fuel is reformed into hydrogen and carbon monoxide by a thermal decomposition reaction using heat obtained from the power plant or a reaction using a catalyst, and the gas turbine combustion is performed. A power plant comprising: a fuel reforming apparatus for setting a hydrogen content of a hydrocarbon-based fuel supplied to a reactor to 1 to 10 vol%. 2. The power plant according to claim 1, wherein the hydrocarbon fuel is partially reformed to reduce the hydrogen content of the hydrocarbon fuel to 1 to 10 vol%. 3. A method of completely reforming a part of the hydrocarbon-based fuel and mixing it with an unreformed hydrocarbon-based fuel to reduce the hydrogen content of the hydrocarbon-based fuel to 1 to 10% by volume. The power plant according to claim 1, wherein the power is supplied to the gas turbine combustor. 4. The fuel reformer according to claim 1, wherein a part of the hydrocarbon-based fuel is reformed, and the reformed hydrocarbon-based fuel is supplied from a fuel nozzle to the gas turbine combustor in a different system from the unreformed hydrocarbon-based fuel. The power plant according to claim 1. 5. The gas turbine combustor according to claim 1, wherein the gas turbine combustor premixes a hydrocarbon-based fuel and combustion air and supplies the mixture to a combustion chamber. Power plant. 6. The heat for the reforming is obtained from one or more of the exhaust gas of the gas turbine, the gas turbine combustor, the transition piece of the gas turbine combustor, or the turbine blade of the gas turbine. The power plant according to any one of claims 1 to 5, which is obtained. 7. The concentration of an unburned component such as a hydrocarbon component or a carbon monoxide component in the gas discharged from the gas turbine combustor is monitored, and the unburned component such as the hydrocarbon component or the carbon monoxide component is monitored. The power plant according to any one of claims 1 to 6, further comprising a monitoring control unit that controls a reforming rate of the hydrocarbon-based fuel so that the concentration becomes equal to or lower than a predetermined value. 8. A power plant for driving a gas turbine with combustion gas obtained by burning a hydrocarbon-based fuel in a gas turbine combustor to rotate a generator coupled to the gas turbine to output electric power In the operating method, at least a part of the hydrocarbon-based fuel is reformed into hydrogen and carbon monoxide using heat obtained from the power generation plant to reduce the hydrogen content of the hydrocarbon-based fuel to 1 to 10%.
A method for operating a power plant, wherein the gas turbine is burned in the gas turbine at a vol%. 9. The concentration of an unburned component such as a hydrocarbon component or a carbon monoxide component in the gas discharged from the gas turbine combustor is monitored, and the unburned component such as the hydrocarbon component or the carbon monoxide component is monitored. 9. The power plant operating method according to claim 8, wherein the reforming ratio of the hydrocarbon-based fuel is controlled so that the concentration becomes equal to or lower than a predetermined value.