JPH1130131A - Gasification compound electric power plant and method for operating it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sufficiently decrease the concentration of nitrogen oxide as well as to enable mixing and supplying of nitrogen without deteriorating efficiency of a plant. SOLUTION: A gasification compound electric power plant is provided with a gasification furnace 51 for producing combustion gas for a gas turbine, and an oxygen manufacturing device 59 for separating air from a compressor into oxygen and nitrogen and for producing oxygen for combustion of the gasification furnace, coal is gasified by taking oxygen obtained by the oxygen manufacturing device as oxidizing agent for the gasification furnace, and the gasified gas is burnt by a gas turbine combustor through a fuel nozzle and a nozzle body for supplying fuel gas to the fuel nozzle. Nitrogen obtained when air is separated by the oxygen manufacturing device 59 is injected into a gas passage formed between the fuel nozzle of the gas turbine combustor 2 and the nozzle body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gasification power plant and a method of operating the same. The present invention relates to a gasification combined cycle power plant in which heavy oil, coal, or the like is gasified, and the gasified gas is burned in a gas turbine combustor.

[0002]

2. Description of the Related Art A gasification and power generation plant of this type, which is conventionally generally used, is disclosed in, for example, Japanese Utility Model Laid-Open Publication No. Sho 57-168735. It is used as fuel for turbine combustors. Further, in this case, nitrogen obtained in the plant is supplied to the combustor in order to reduce the emission concentration of nitrogen oxides (NOx) discharged from the combustor.

On the other hand, with respect to the structure of a fuel nozzle used in this type of plant, see, for example, Japanese Patent Application Laid-Open No. 5-86902.
As described in Japanese Patent Publication No.
A configuration in which the combustion gas flow is prevented from flowing back to another combustor through the gas injection holes when burning other types of fuel until before the operation mode is switched from acceleration to gas combustion. Nozzles are known.

[0004]

In this type of gasification combined cycle power plant, when a fuel such as heavy oil or coal is gasified in a gasification furnace, the gas concentration depends on the concentration of an oxidizing agent supplied to the gasification furnace. The properties of the gas to be converted, that is, the composition and heat value of the gas supplied to the gas turbine vary greatly.

When gas such as coal is gasified with oxygen in a gasification furnace, the amount of generated gas is smaller than when gasification is performed by an air oxidation method, so that the furnace can be downsized. In addition, it is possible to expect the effect that the amount of recycling of the char (ash particles + unburned carbon) is small.

On the other hand, the calorific value of the gasified gas by oxygen oxidation is about 2.5 times that of the gas obtained by the air oxidation method and about one third of that of natural gas. However, when the gas is burned in a gas turbine combustor, the ideal flame ratio of fuel and air, that is, the maximum flame temperature at the stoichiometric mixture ratio is:
About 200 ° C. higher than that of natural gas. Therefore, in diffusion combustion in which fuel and air are purely supplied from separate flow paths and burned, the concentration of nitrogen oxides discharged from the gas turbine combustor increases in proportion to the increase in the stoichiometric mixture flame temperature. And eventually to environmental issues.

On the other hand, the premixed combustion system in which fuel and air are preliminarily mixed and burned at a uniform temperature is a powerful combustion system capable of reducing the emission concentration of nitrogen oxides discharged from the combustor. Gas burning speed (flame propagation speed)
Is several times faster than natural gas, and because of the nature of such a gas, it is very difficult to reduce NOx by premixed combustion, and it is difficult to obtain nitrogen (extracted air from a gas turbine, It is considered that a low NOx combustion method using air sent from an air compressor as a medium for flame temperature dilution is an effective means.

The low NOx combustion method using nitrogen is as follows: 1) A method of injecting and mixing nitrogen into combustion air of a gas turbine combustor. 2) A method of injecting and mixing nitrogen into the flame in the combustor. 3) A method of injecting and mixing nitrogen into the fuel to reduce the calorific value of the fuel can be considered.

[0009] Each of the methods focuses on reducing the concentration of nitrogen oxides discharged from the gas turbine combustor by reducing the maximum flame temperature (local flame temperature) of the stoichiometric mixture ratio. However, in the methods 1) and 2), the effect of low NOx tends to be dilute unless nitrogen is mixed instantaneously in the course of combustion.

In view of the above, the method of mixing the fuel with nitrogen to reduce the calorific value of the fuel is the method in which the flame temperature at the stoichiometric mixture ratio becomes the lowest among the above three options, and thus the low NOx combustion A considerable effect can be expected as a method. However, since the pressure of the gas supplied from the gasifier is more than twice as high as the compressor discharge air pressure of the gas turbine, the pressure must be increased to a considerable pressure in order to mix nitrogen into the fuel. However, there is a tendency to reduce the efficiency of the plant.

The present invention has been made in view of the foregoing, and it is an object of the present invention to be able to mix and supply nitrogen without impairing the efficiency of a plant and to sufficiently reduce the concentration of nitrogen oxides. It is an object of the present invention to provide a gasification power plant of this kind and a method of operating the same.

[0012]

That is, the present invention provides a gasification furnace for producing a fuel gas for a gas turbine, and a method for separating air from a compressor into oxygen and nitrogen to produce oxygen for combustion in the gasification furnace. An oxygen producing apparatus for producing heavy oil or coal as an oxidizing agent for the gasification furnace using the oxygen obtained by the oxygen producing apparatus, and gasifying the gas into a fuel nozzle and a fuel nozzle. In a gasification combined cycle power plant configured to burn in a gas turbine combustor through a nozzle body that supplies fuel gas to a nozzle, nitrogen obtained when air is separated by the oxygen production apparatus is used as the gas. This is formed so as to be injected into a gas flow path formed between a fuel nozzle and a nozzle body of a turbine combustor, thereby achieving an intended purpose.

In this case, the fuel nozzle is provided with a fuel nozzle for burning a fuel other than gasified gas at the axial center of the fuel nozzle, and a plurality of gas injection holes are formed on a concentric circle on the outer peripheral side thereof. The gas injection holes and the air injection holes are arranged alternately and concentrically on the outer peripheral side of the gas injection holes, and the nitrogen injection holes or the gas injection holes are provided in the gas passage between the fuel nozzle and the nozzle body. It is formed so as to arrange a nitrogen injection nozzle.

The fuel nozzle has a throttle portion in a gas throat portion thereof, has a plurality of annular injection holes in the throttle portion, and supplies air when burning other fuels other than gasified gas. A line and a nitrogen line supplied at the time of gas firing are provided so as to communicate with the injection holes, and a fluid supplied to the gas throat portion via the injection holes is switched so as to be switched according to the fuel used.

Further, there is provided a gasification furnace for generating fuel gas for a gas turbine, and an oxygen production apparatus for separating air from the compressor into oxygen and nitrogen to generate combustion oxygen for the gasification furnace. A gasification of heavy oil or coal using oxygen obtained by the oxygen production apparatus as an oxidizing agent for the gasification furnace, and a gas nozzle for supplying the gasified gas to a fuel nozzle and a fuel gas to the fuel nozzle A gasification combined cycle power plant that supplies and burns to a gas turbine combustor through a gas turbine, and uses a fuel other than gasified gas as an ignition / startup fuel for the gas turbine when starting the gas turbine. It also has an atomizing air compressor that is used as fuel spray air, and supplies a part of the discharged air to the gas passage of the fuel nozzle before the gas turbine is ignited, and the gasified gas is discharged. In the operating method of the combined gasification combined cycle plant in which the combustion state is switched from other fuels to gasified gas after the state in which the gasified gas can be supplied to the turbine, the gasified gas is in a state in which the gasified gas can be supplied to the gas turbine. When switching the combustion state from another fuel to a gasified gas, in response to the switching, nitrogen obtained from the oxygen producing apparatus is supplied to a gas passage between the nozzle body and the fuel nozzle to supply the gas. The fuel is burned while being mixed with the gas supplied from the gasification furnace.

In this case, the ignition of the gas turbine
When the fuel used as a start-up is medium calorie gas supplied from a gasifier, the amount of nitrogen supplied to the gas passage between the fuel nozzle and the nozzle body is controlled by a control valve provided on the upstream side of a nitrogen supply line. The control is performed in accordance with the ignition characteristics of the gas turbine.

That is, in the gasification power plant thus formed, nitrogen obtained from the oxygen separator is
In order to supply the gas in the gas passage between the fuel nozzle and the nozzle body, it is possible to supply the nitrogen without increasing the supply pressure of the nitrogen above the discharge pressure of the gasifier, and to reduce the calorific value of the fuel without impairing the efficiency of the plant. It can be reduced.

That is, the heavy oil or coal gasification gas supplied from the gasification furnace has passed through a gas purification device (pressure P1) disposed downstream of the gasification furnace for removing impurities in the gas. Thereafter, a pressure control valve (P2) and a fuel flow control valve (P3) for controlling the fuel flow rate of the gas turbine combustor, and further, a fuel chamber (P5) through a fuel nozzle body (P4) and a gas injection hole of the fuel nozzle. Will be supplied. In this case, the pressure of each part is P1> P2
>P3>P4> P5, and when the nitrogen supply pressure (PN2) is compared with those pressures, PN2> P
4, P5, PN2 <P1, P2, P3. Therefore, the nitrogen supply position is not mixed at the outlet of the gasification furnace where the gas pressure is high, but downstream of the pressure control valve and the flow rate control valve for controlling the fuel of the gas turbine, and furthermore, the swirling flow of the nozzle body and the fuel nozzle. By injecting between the road entrances, it becomes possible to supply nitrogen without increasing the supply pressure of nitrogen above the discharge pressure of the gasifier.

As described above, the pressure of the gasified gas in the fuel nozzle may be any pressure at which the gasified gas can be ejected from the swirl flow path at a certain flow rate, and the pressure is slightly higher than the pressure in the combustion chamber. is there. Therefore, since nitrogen is supplied to the gas passage between the fuel nozzle and the nozzle body, the power consumption of the nitrogen pressurizing compressor provided downstream of the oxygen separator can be reduced. This greatly affects the system efficiency of the entire plant.

Further, when nitrogen is mixed in the fuel, the local flame temperature is lower in the diffusion combustion system in which the fuel and air are supplied from separate flow paths than in the case where nitrogen is mixed in the flame. When nitrogen is mixed and diluted in a flame, the flame temperature tends to be distributed depending on the performance of the degree of mixing. Therefore, it is considered that the concentration of nitrogen oxides discharged from the combustor can be reduced by supplying a gas in which the calorific value of the gas in the fuel is reduced, and in the present invention, low NO x Combustion is possible.

According to the plant operating method of the present invention,
During combustion of other fuels such as light oil in which the differential pressure between the combustor and the gas passage is reduced, purge air is supplied, so that it is possible to prevent combustion gas from flowing into other cans via the gas passage. . Further, when gasification gas can be supplied from the gasification furnace to the gas turbine, calorific value of fuel can be reduced by supplying nitrogen to the gas passage between the nozzle body and the fuel nozzle, Low NOx combustion becomes possible from the time of switching.

In the case where the fuel used for igniting / starting the gas turbine is medium calorie gas supplied from the gasifier, the fuel composition depends on the gas composition supplied from the gasifier (the composition changes depending on the coal type of coal). Since the flow rate of nitrogen mixed into the gas through the nitrogen injection hole or nitrogen injection nozzle can be changed by the control valve provided in the nitrogen supply line, the gas injection flow rate during direct gas ignition of the combustor can be changed. Thus, a circulating flow formed on the front surface of the fuel nozzle can be secured.

In the case of the present invention, the gas jet velocity is designed to be the total flow rate of the supplied medium calorie gas and the mixed nitrogen flow rate. Spout velocity (inversely proportional to calorific value)
Is extremely slow, and it is possible that the fuel may not reach the vicinity of the spark plug, and it is also difficult to form a circulating flow in front of the fuel nozzle. Nitrogen is introduced into the fuel while setting it within the range and at the same time as the gas jetting velocity is increased to some extent.

When a fuel such as gas oil other than gasified gas is used as the fuel for starting and igniting the gas turbine, a part of the discharge air of the atomizing compressor is used before the gas turbine is ignited.
Inject gas from the nitrogen injection hole or nitrogen injection nozzle in the gas throat section, and when starting the fuel switch from light oil to gas combustion, use the gas supplied from the gasifier inside the fuel nozzle and the nitrogen injection hole in advance. In order to prevent the formation of premixed air with the supplied air, the amount of nitrogen to be supplied is increased as the gas flow rate is increased, that is, the gas combustion ratio is increased (light oil fuel is decreased), and the concentration of oxygen mixed into the fuel is reduced. Let it.

As described above, since the burning speed of medium calorie gas (flame propagation speed) is about three times faster than that of natural gas, atomized air is supplied in the gas throat. When the medium calorie gas is supplied to the gas flow path, there is a possibility that the flame (premixed gas of the medium calorie gas) propagates to the upstream side using the light oil combustion gas as a fire.

By employing the above-described operation method, the mixture of the atomized air (purge air) and the gas, which is concerned at the initial stage of switching the combustion state from light oil to gas, propagates the flame into the nozzle flow path. Can be prevented.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the illustrated embodiments. Before describing specific structures such as a gas turbine combustor and a fuel nozzle, a gasification power plant and its operation will be described first. FIG. 1 is a system diagram of a heavy oil gasification or coal gasification combined cycle power plant that gasifies a fuel such as heavy oil or coal by oxygen oxidation, burns the gas, and generates power via a turbine and a generator.

Here, the description will be made on the assumption that a coal gasification combined cycle power plant is used and that light oil is used as a fuel for starting the gas turbine. This plant mainly consists of the following equipment. That is, gasification furnace 51, gas purification (desulfurization device 52, dust removal device 53), gas turbine (compressor 1, combustor 2, turbine 3), oxygen production device 59, exhaust heat recovery boiler 58, steam turbine 57, etc. It consists of. The feature of this plant is that the oxidizing agent 104 required for the gasification furnace 51 has a cycle configuration in which it is extracted from a gas turbine (compressor 1, combustor 2, and turbine 3).

The gas turbine driven by external power or the like is ignited in the combustor 2 using light oil 105 sent from the light oil tank 64 as fuel, and is started and accelerated. Then, after the speed is increased to a predetermined speed, a self-sustaining operation is started, and after reaching the no-load rated rotation speed of the gas turbine, the load is gradually started by incorporating the generator 56.

On the other hand, the oxidizing agent required for the gasification furnace 51 is supplied from the oxygen producing device 59, and the process is as follows. That is, the backup compressor 6
0 or bleed air 1 bleed from the gas turbine
04 is supplied to an oxygen production device 59, where it is separated into oxygen 61 and nitrogen 62. The separated oxygen 61 is supplied to the gasification furnace 51, and the nitrogen 62 is supplied to the gas turbine combustor 2.

In the gasification furnace 51, the fuel 100 is burned by the supply of oxygen 61, and the gasification gas 101 can be supplied as the gasification furnace load increases. Immediately after the activation of the gasification furnace 51, the temperature and the calorific value of the generated gas 101 are extremely low. Therefore, the gasified gas 101 is processed in the gas processing furnace 54 until the load increases (the calorific value increases). .
Therefore, until the load on the gasification furnace 51 increases, the gas turbine combustor 2 burns light oil as the main fuel.

On the other hand, the steam turbine 57 is driven by steam 103 generated by using exhaust heat obtained from the gas turbine, and the generator 56 is driven by the rotational energy of the turbine 57. Thereafter, the load on the gasification furnace 51 increases, and the predetermined gas 101 can be supplied to the combustor 2. Then, in the combustor 2, a fuel switching operation from oil combustion to coal gas combustion is performed, and the gas burning operation is performed. Switch to After the fuel switching operation to gas firing is completed,
Increasing the flow rate of 01 also increases the gas turbine output.

Next, the structures of the gas turbine combustor and the fuel nozzle will be described with reference to FIG. This figure is a partially enlarged view of the combustor head (fuel injection side). This combustor 2 cools a combustor outer cylinder 206 as a pressure vessel, a liner 208 as a combustion chamber, and a liner 208. It comprises a flow sleeve 207, a fuel nozzle for holding a flame, and the like.

The fuel nozzles are arranged at the axial center of the combustor (at the center in the radial direction and at the head of the combustor). Gas injection holes 124 for performing gas combustion,
Air injection holes (swirler) for supplying combustion air 106
125.

The air 106 sent from the compressor is supplied from the combustion air holes provided in the liner 208, which is a combustion chamber, into the liner as indicated by arrows 106A and 106B indicating the flow. The swirler air 106C is the remaining air after the combustion air is branched into the liner.

Next, the structure of the fuel nozzle will be described with reference to FIGS. This figure shows an example in which a gas throat portion is provided with an injection hole that shares an air supply line and a nitrogen supply line. The fuel nozzle comprises gas 101 and light oil 10
5 is provided with a nozzle 123 for burning other fuels such as light oil at the axis of the nozzle as described above, and a gas injection hole 124 and an air Each has an injection hole 125.

A gas throat 120 serving as a gas flow path in the fuel nozzle is provided with a throttle 121 for providing a pressure difference between the combustion chamber and the gas flow path.
2 are arranged. The light oil 105 is a light oil nozzle 123
Further, the light oil atomizing air 110 is supplied from a separate atomizing compressor, which burns in a combustion chamber through a fuel nozzle while mixing with air supplied from a swirler.

At this time, in order to prevent the generated combustion gas from flowing backward through the gas injection holes 124 having a small differential pressure between the combustors and flowing out to other combustion cans only at the time of light oil combustion, atomizing air is used. A part of the nozzle 110 is injected from the injection hole 122. The air 110 jetted from the nitrogen jet holes 122 prevents backflow to other cans and also serves as light oil combustion air jetted from the light oil nozzle 123.

Thereafter, as the gasification furnace load increases, the gasification gas can be supplied to the gas turbine, and then the gas 101 is supplied into the nozzle body. Along with the gas supply, the air 110 supplied to the gas throat is gradually decreased, and the flow rate of nitrogen 102 for reducing the calorific value of the fuel is increased by the control valve 70 to increase the gas 10.
1 and the nitrogen 102 supplied from the nitrogen injection hole 122 are mixed in the nozzle, and the mixed gas is ignited using the spark of light oil.

After the ignition of the gas is completed, the combustion ratio of the gas (reducing the combustion ratio of the light oil) is increased, and the operation is finally performed by gas firing.

FIGS. 5 and 6 show the shapes of the nitrogen injection holes of the fuel nozzle. In these figures, the gas throat portion and the nitrogen supply portion of the fuel nozzle are partially enlarged. In the fuel nozzle, a nitrogen injection hole 122-a for supplying nitrogen into the gasified gas is provided in the gas passage, and nitrogen 102 is supplied to the gas 1 through the injection hole 122-a.
01 to form a low calorific value gas.

The injection hole 122-a is provided with the gas throat 1
A plurality of rings are arranged in 20 parts. By arranging a plurality of such components, it is possible to mix nitrogen into the gas while dispersing it, so that the gas and nitrogen can be mixed relatively uniformly within a short distance in the nozzle flow path.

FIGS. 7 and 8 show an example in which a nitrogen injection nozzle 122-b is attached instead of the nitrogen injection hole 122-a. The nitrogen injection nozzle 122-b is also the nitrogen injection hole 12
There is an effect similar to 2-a.

FIGS. 9 and 10 show the nitrogen injection nozzle 12.
This is an example when 2-b is provided in a gas passage of a nozzle body. The nitrogen 102 supplied from the oxygen separator has a structure that can be supplied into the gas passage 120 through a nitrogen injection nozzle 122-b arranged annularly in the gas passage of the nozzle body.

Light oil is injected in the form of a mist from the nozzle 123 and burns in the combustor, and after the gas 101 can be supplied to the combustor, nitrogen 102 is injected from the injection nozzle 122 and the gas 101 and the gas passage 120 are discharged. A gas having a low calorific value is supplied from the gas injection holes 124 to switch the combustion state from light oil to gas combustion.

FIGS. 11 and 12 schematically show the flow rates of light oil and gas when switching the combustion state from light oil to gas combustion, the flow rate of air supplied to the gas throat and the flow rate of nitrogen mixed in the gas during light oil combustion. It is a thing expressed in a way.

When switching the combustion state from light oil to gas in a gas turbine combustor, it is general to operate the gas turbine with the output of the gas turbine, that is, the temperature of the gas at the outlet of the combustor being constant. The gas flow rate is gradually increased at the same time as the light oil flow rate is gradually decreased, and the heat transfer to the gas is performed by using the heat energy at the time of light oil combustion. Eventually, the combustion amount of light oil is reduced to zero, and the gas is fired exclusively.

In this series of operations, during combustion of light oil,
The air flow rate supplied to the gas throat section is also reduced in accordance with the decrease in light oil flow rate. In addition, the flow rate of nitrogen supplied for the purpose of reducing the calorific value of the gasified gas increases the supply amount in accordance with the operation of reducing the air amount.

If the amount of air is supplied at a constant level during the combustion state switching operation, a premixed air of medium calorie gas and air is formed, and there is a possibility that a flame may propagate in the nozzle. On the other hand, if the supply of air is stopped before the start of the fuel switching operation and only nitrogen gas is supplied to the gas throat, unstable combustion may be induced at the time of light oil alone combustion. Therefore, by operating in this manner, smooth fuel switching is possible.

FIG. 13 schematically shows the flow rates of gas and nitrogen when there is no starting fuel such as light oil. What is shown is the range of the ignition and acceleration modes of the gas turbine. The gaseous gas injection holes are designed based on the total flow rate of the gaseous gas and nitrogen, so when using an ignition system with gas, the supply gas from the gas injection holes at the time of ignition is used. The jet velocity decreases.

In order to avoid this, it is operated to supply nitrogen in order to secure a certain flow rate of gas ejected from the gas injection holes while securing a ignitable gas component (calorific value). At about the same time as the ignition, nitrogen is supplied from the above-described nitrogen injection hole. After the ignition of the gas turbine is completed, the flow rate of the gasified gas and the flow rate of the nitrogen gas are gradually increased to enter the speed-up mode.

FIG. 14 shows the nitrogen oxide (NO) discharged from the combustor when the amount of nitrogen supplied to the fuel is changed.
3 shows the density of x). The figure shows a comparison of the NOx emission concentration between the case where nitrogen is mixed in the gas using the nitrogen injection hole and the case where nitrogen is mixed in the flame in the combustor. It can be seen that the concentration of the discharged NOx decreases as the nitrogen supply amount increases. In addition, it can be seen that the reduction rate of NOx discharged from the combustor changes depending on the nitrogen supply position (mixing degree).

FIG. 15 shows the power transmission end efficiency ratio when the nitrogen supply pressure is changed in the plant. It can be seen that the efficiency (transmission end efficiency) of the entire plant changes depending on the nitrogen discharge pressure obtained by the oxygen separator.

As described above, in the plant formed as described above, since the nitrogen obtained from the oxygen separator is supplied to the gas passage between the fuel nozzle and the nozzle body, the nitrogen The supply pressure can be supplied without increasing the supply pressure higher than the discharge pressure of the gasification furnace, and the calorific value of the fuel can be reduced without impairing the efficiency of the plant.

Further, since nitrogen is mixed with the fuel and supplied, the diffusion combustion method in which the fuel and the air are supplied from separate flow paths respectively has a more localized flame than the case where the nitrogen is mixed into the flame. The temperature can be lowered, and the concentration of nitrogen oxides discharged from the combustor can be efficiently reduced.

[0056]

As described above, according to the present invention, it is possible to mix and supply nitrogen and suppress the concentration of discharged nitrogen oxides without impairing the efficiency of the plant. This type of gasification power plant can be obtained.

[Brief description of the drawings]

FIG. 1 is a system diagram showing one embodiment of an integrated gasification combined cycle power plant of the present invention.

FIG. 2 is an enlarged sectional view of a main part showing an embodiment of the gas turbine combustor of the integrated gasification combined cycle power plant of the present invention.

FIG. 3 is a vertical sectional side view showing one embodiment of a fuel nozzle of the integrated gasification combined cycle plant of the present invention.

FIG. 4 is a front view of FIG. 3;

FIG. 5 is a vertical sectional side view showing another embodiment of the fuel nozzle of the integrated gasification combined cycle plant of the present invention.

FIG. 6 is a sectional view taken along line AA of FIG.

FIG. 7 is a vertical sectional side view showing another embodiment of the fuel nozzle of the integrated gasification combined cycle plant of the present invention.

FIG. 8 is a sectional view taken along line BB of FIG. 7;

FIG. 9 is a vertical sectional side view showing another embodiment of the fuel nozzle of the integrated gasification combined cycle power plant of the present invention.

FIG. 10 is a front view of FIG. 9;

FIG. 11 is a characteristic diagram of fuel switching flow rate control (air, nitrogen) according to one embodiment of the present invention.

FIG. 12 is a characteristic diagram of fuel switching flow rate control (air, nitrogen) according to one embodiment of the present invention.

FIG. 13 is a characteristic diagram of flow rate control (gas, nitrogen) at the time of direct gas ignition according to one embodiment of the present invention.

FIG. 14 is a characteristic diagram showing the effect of reducing NOx.

FIG. 15 is a characteristic diagram showing a plant efficiency effect.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Compressor, 2 ... Combustor, 3 ... Turbine, 51 ... Gasifier, 52 ... Desulfurizer, 53 ... Dust remover, 56 ... Generator
57 steam turbine, 58 heat recovery boiler, 59
Oxygen producing apparatus, 61 ... oxygen, 62 ... nitrogen, 64 ... light oil tank, 101 ... gas, 102 ... nitrogen, 104 ... oxidizing agent,
Reference numeral 105: light oil, 120: gas throat, 122: injection nozzle, 122a, 122b: nitrogen injection hole, 123: oil nozzle, 124: gas injection hole, 125: air injection hole, 206:
Outer cylinder, 208 ... liner.

──────────────────────────────────────────────────続 き Continuing on the front page (51) Int.Cl. ⁶ Identification symbol FI F23R 3/28 F23R 3/28 FB (72) Inventor Seiichi Kirikami 3-1-1 Kochicho, Hitachi-shi, Hitachi, Ibaraki Stock Hitachi, Ltd., Hitachi Plant (72) Inventor, Katsuo Wada 3-1-1, Sachimachi, Hitachi, Hitachi, Ibaraki, Japan Hitachi, Ltd.

Claims (6)

[Claims] 1. A gasifier for producing a fuel gas for a gas turbine, and an oxygen producing apparatus for separating air from a compressor into oxygen and nitrogen to produce oxygen for combustion in the gasifier. A gasification of heavy oil or coal using oxygen obtained by the oxygen production apparatus as an oxidizing agent for the gasification furnace, and a gas nozzle for supplying the gasified gas to a fuel nozzle and a fuel gas to the fuel nozzle In a combined gasification combined cycle power plant that is configured to burn in a gas turbine combustor through a gas turbine combustor, nitrogen obtained when air is separated by the oxygen production device is used as a fuel nozzle and a nozzle body of the gas turbine combustor. Characterized by being formed so as to be injected into a gas passage formed between the gasification combined cycle power plant. 2. A gasifier for producing fuel gas for a gas turbine, and an oxygen producing device for separating air from a compressor into oxygen and nitrogen to produce oxygen for combustion in the gasifier. A gasification of heavy oil or coal using oxygen obtained by the oxygen production apparatus as an oxidizing agent for the gasification furnace, and a gas nozzle for supplying the gasified gas to a fuel nozzle and a fuel gas to the fuel nozzle In a combined gasification combined cycle power plant that is configured to burn in a gas turbine combustor through a gas turbine, air is separated from an oxygen production device in a gas flow path between a nozzle body of the gas turbine combustor and the fuel nozzle. A combined gasification power plant comprising a plurality of nitrogen injection holes or nitrogen injection nozzles for injecting and mixing the nitrogen obtained at the time into gasification gas supplied from a gasification furnace. 3. The fuel nozzle includes a fuel nozzle for burning a fuel other than gasified gas at the axial center of the fuel nozzle, and a plurality of gas injection holes arranged on a concentric circle on an outer peripheral side thereof. In addition, gas injection holes and air injection holes are respectively arranged alternately on concentric circles on the outer peripheral side of the gas injection holes, and in a gas passage between the fuel nozzle and the nozzle body,
3. The integrated gasification combined cycle plant according to claim 2, wherein the nitrogen injection hole or the nitrogen injection nozzle is arranged. 4. The fuel nozzle has a throttle portion in a gas throat portion thereof, has a plurality of annular injection holes in the throttle portion, and supplies fuel other than gasified gas when burning. An air line and a nitrogen line supplied at the time of gas firing are provided so as to communicate with the injection hole, and the fluid supplied to the gas throat portion via the injection hole is formed so as to be switched according to the fuel used. 3. The integrated gasification combined cycle plant according to 2. 5. A gasifier for generating fuel gas for a gas turbine, and an oxygen producing device for separating air from a compressor into oxygen and nitrogen to generate combustion oxygen for the gasifier. A gasification of heavy oil or coal using oxygen obtained by the oxygen production apparatus as an oxidizing agent for the gasification furnace, and a gas nozzle for supplying the gasified gas to a fuel nozzle and a fuel gas to the fuel nozzle A gasification combined cycle power plant that supplies and burns to a gas turbine combustor via a gas turbine, and uses a fuel other than gasified gas as an ignition / startup fuel for the gas turbine when starting the gas turbine. Combined with an atomizing air compressor that is used as fuel spray air, a part of the discharged air is supplied to the gas passage of the fuel nozzle before the gas turbine is ignited, and the gasified gas is supplied to the gas turbine. After the bottle can be supplied,
In the operation method of a gasification combined cycle power plant in which a combustion state is switched from another kind of fuel to a gasified gas, the gasified gas becomes a state capable of being supplied to a gas turbine, and the combustion state is changed from another kind of fuel to a gasified gas. At the time of switching, in response to the switching, nitrogen obtained from the oxygen producing apparatus is supplied to a gas passage between the nozzle body and the fuel nozzle to be mixed with gas supplied from the gasification furnace and burned. A method for operating an integrated gasification combined cycle plant, wherein the method is operated so as to cause the operation. 6. When the fuel used for igniting / starting the gas turbine is medium calorie gas supplied from a gasifier, the amount of nitrogen supplied to a gas passage between the fuel nozzle and the nozzle body is set to nitrogen. 6. The operating method for an integrated gasification combined cycle power plant according to claim 5, wherein the control valve provided on the upstream side of the supply line is controlled in accordance with the ignition characteristics of the gas turbine.