JP2001173461A - Power generation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve reliability of a sub-nozzle air supply system which supplies pressurized air to a sub-nozzle of a dual burner of a gas turbine. SOLUTION: This power generation system 10 has a gas turbine power generation device 16 which adopts fuel gas generated in a gasifying oven 12 as main fuel, an air separation device 18 which generates oxidizing agent and nitrogen gas, an oxidizing agent booster 22 which boosts the oxidizing agent and supplies it to the gasifying oven, and a nitrogen gas booster 24 which boosts the nitrogen gas and supplies it to the gasifying oven. In such a power generation system 10, a sub-nozzle air supply system 20 is arranged for supplying pressurized air to a sub-nozzle, which is adopted to one of promotion of atomization of starting liquefied fuel, cooling the sub-nozzle after starting, and purging the sub-nozzle. The air boosted by a compressor 15a of the gas turbine power generation device 16, or gas derived therefrom, can be supplied to the sub-nozzle air supply system 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power generation system for gasifying organic matter such as coal and petroleum and using the gas as a main fuel gas.

[0002]

2. Description of the Related Art Hitherto, a gasification power generation system has been proposed in which coal or oil is gasified to generate a fuel gas, and the fuel gas is used as fuel for driving a gas turbine power generation device. In this gasification power generation system, fossil fuels such as coal, petroleum coke, and heavy oil are gasified in a gasifier using oxygen, oxygen-enriched air or air as an oxidizing agent, and carbon monoxide and hydrogen are used as main combustion gas components. The purified fuel gas is used as a fuel for a gas turbine power generation device through a gas purification step of removing a char and a sulfur component from the generated fuel gas.

When oxygen or oxygen-enriched air is used as an oxidizing agent, high-purity oxygen gas or oxygen-enriched air containing about 40% or more by volume of oxygen is obtained by separating nitrogen from air by an air separation device. Is produced as an oxidizing agent.
In the oxidant generation process in this air separation device, nitrogen gas is generated as a by-product. The oxidant generated by the air separation device is pressurized by an oxidizer booster and supplied to a gasification furnace. Nitrogen gas, a by-product, is pressurized by a nitrogen gas booster and supplied to a gasification furnace to be used as a carrier medium for solid fuel such as pulverized coal, or supplied to gas purification equipment and used as a char carrier medium. You.

When starting the gasification power generation system,
In order to sufficiently warm up a gasification furnace or the like or to supply an oxidizing agent to the gasification furnace, the gas turbine needs to be started in advance with a starting liquid fuel (eg, light oil and kerosene). . Therefore, the gas turbine includes a dual combustor having a main nozzle for burning the fuel gas as the main fuel and a sub-nozzle for burning the liquid fuel as the starting fuel.

[0005]

In a sub-nozzle of a dual combustor of a gas turbine, an atomizing medium for atomizing liquid fuel at the time of start-up uses a sub-nozzle at the sub-nozzle after extinguishing the starting liquid fuel. During normal operation, a purge medium for preventing the liquid fuel remaining in the nozzle from carbonizing is swept for cooling in order to protect the nozzles of the sub-nozzles that are not used from the radiant heat of the combustion gas in the main nozzle. Media is required. In order to supply such a spray medium, a purge medium, and a sweep medium to the sub-nozzle, a sub-nozzle air supply system including a sub-nozzle air booster that pressurizes periodic air is conventionally provided.

When the gasification power generation system shifts from the start-up process to normal operation, a failure occurs in the sub-nozzle air supply system, particularly in the sub-nozzle air booster. To be damaged, the gas turbine power plant itself must be shut down. In order to prevent this, the sub-nozzle air booster needs to be constituted by two compressors as backup. However, due to the failure of the sub-nozzle air booster, which does not occur frequently, preparing two compressors is economically burdensome for the expected effect.

An object of the present invention is to solve the problems of the prior art, and to provide a sub-nozzle air supply system for supplying pressurized air to a sub-nozzle of a dual combustor of a gas turbine without increasing cost. The aim is to increase the reliability of the.

[0008]

According to the present invention, there is provided a gasification furnace for producing a fuel gas by gasifying a solid or liquid organic substance with an oxidizing agent, and purifying the produced fuel gas. Gas purification equipment, a gas turbine power generation device using the purified fuel gas as a main fuel, an air separation device for generating an oxidant and nitrogen gas from air, and pressurizing the oxidant to the gasification furnace. In a power generation system including an oxidizing agent booster to be supplied and a nitrogen gas booster to boost the nitrogen gas and supply the gas to a gasification furnace or a gas purification facility, the gas turbine power generation device burns the generated gas. And a combustor having a sub-nozzle for burning the start-up liquid fuel, wherein the power generation system at least promotes atomization of the start-up liquid fuel,
A sub-nozzle air supply system including a sub-nozzle air booster for pressurizing and supplying ambient air to the sub-nozzle for use in either cooling the sub-nozzle or purging the sub-nozzle after startup The gist of the present invention is a power generation system characterized in that a gas having the air pressurized by a compressor of the gas turbine power generation device as its bottom source can be supplied to a sub-nozzle air supply system.

According to the present invention, even when the sub-nozzle air pressure booster fails, the gas having the pressure boosted by the compressor of the gas turbine power generation device as its bottom source is supplied to the combustor auxiliary system. Without stopping the entire power generation system, only the sub-nozzle air booster can be stopped and repaired. Therefore, according to the present invention, it is possible to increase the reliability of the sub-nozzle air supply system that supplies pressurized air to the sub-nozzle of the dual combustor of the gas turbine without increasing the cost.

According to one feature of the present invention, when the air pressurized by the compressor of the gas turbine generator is pressurized and supplied as raw air to the air separation device, the compressor and the air separation A raw material air booster may be provided between the apparatus and the apparatus, and a part of the air pressurized by the raw air booster may be supplied to the auxiliary nozzle air supply system.

According to another feature of the present invention, when a part of the air pressurized by the compressor of the gas turbine generator is directly supplied as raw material air to the air separation device, the air separation device may include: Separated from the feed air,
The generated nitrogen gas can be supplied to the auxiliary nozzle air supply system.

According to still another feature of the present invention, the air pressurized by the compressor of the gas turbine generator is further pressurized and supplied to the gasification furnace together with the oxidant generated by the air separation device. In this case, an auxiliary compressor may be provided between the compressor and the gasification furnace, and a part of the air pressurized by the auxiliary compressor may be supplied to the auxiliary nozzle air supply system.

[0013]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. First, referring to FIG. 1, a power generation system 10 according to a first embodiment of the present invention.
A gasification furnace 12 that gasifies a solid fossil fuel such as coal or petroleum coke or a liquid fossil fuel such as heavy oil and other organic substances to generate a fuel gas; Gas purification equipment 14 for removing and purifying components, compressor 16a, turbine 16
b, a gas turbine generator 16 including a generator 16c and a combustor 16d, and an air separator 18 for separating nitrogen from air to generate an oxidizing agent and supplying the oxidizing agent to the gasification furnace 12.
And are included as main components.

The high-purity oxygen gas or the oxygen-enriched air containing the high-concentration oxygen gas as the oxidant generated in the air separation device 18 is supplied to the oxidant booster 22 through the oxidant supply line 18e. After the pressure is increased to a predetermined pressure, the pressure is supplied to the gasification furnace 12. On the other hand, the nitrogen gas generated by the air separation device 18 is supplied to a nitrogen gas booster 24 through a nitrogen gas supply line 18b and is boosted to a predetermined pressure. Is supplied to the pulverized coal transport path 28 containing the pulverized coal.

The air separation unit 18 can be a so-called cryogenic separation type air separation unit that separates oxygen and nitrogen from air by utilizing the difference between the boiling points of oxygen and nitrogen. It comprises as a main component a vessel and an adsorption tower containing a molecular sieve for removing carbon dioxide and moisture in the atmosphere. In the present embodiment, the air serving as the raw material is configured to use a part of the air pressurized by the compressor 16a of the gas turbine power generator 16. That is, in FIG. 1, the raw material air booster 26 is connected to the outlet or the bleed port of the compressor 16a,
The air pressurized by the compressor 16a or the bleed air from the compressor 16a is further pressurized by the raw air booster 26 and supplied to the air separation device 18 via the raw air line 26a. In the air separation device 18, the supplied compressed air is cooled by a heat exchanger, and then cooled by an expansion turbine (not shown) to generate liquid air in the rectification tower. In the rectification column, the liquid air is rectified to produce oxygen gas or oxygen-enriched air containing high-concentration oxygen gas and nitrogen gas, and each of them is supplied via an oxidant supply line 18a and a nitrogen gas supply line 18b. The oxidizer booster 22 and the nitrogen gas booster 24 are supplied.

As already described in the description of the prior art,
In the gasification power generation system, in order to sufficiently warm up a gasification furnace or the like at the time of startup, or to supply an oxidant to the gasification furnace, the gas turbine uses a liquid fuel for startup, for example, light oil or kerosene. It needs to be launched in advance. Referring to FIG. 2, in the present embodiment, a combustor 16 d of the gas turbine generator 16 includes a main nozzle 34 for burning fuel gas as a main fuel, and a sub-nozzle for burning liquid fuel as a starting fuel. 36, and the main nozzle 34 is disposed on a circumference centered on the sub-nozzle 36. A sweep nozzle 38 is provided between the main nozzle 34 and the sub-nozzle 36 to eject a sweep medium for protecting the sub-nozzle not used during normal operation from the radiant heat of the combustion gas in the main nozzle. ing.

The main nozzle 34 has a fuel gas supply line 14
a, a fuel gas is supplied from the gas purification facility 14 through
A liquid fuel such as light oil or kerosene is supplied to the sub-nozzle from a liquid fuel source (not shown) including a fuel tank, a fuel pump, and the like via a liquid fuel supply pipe 32. The sweep nozzle 38 is supplied with air from the sub-nozzle air supply system 20 (see FIG. 1) via a sub-nozzle air supply line 20g, as described later in detail. It is used as a spray medium for atomization, as a purge medium for preventing carbonization of liquid fuel in the sub-nozzle after extinguishing the sub-nozzle, and as a sweep medium during normal operation.

Referring again to FIG. 1, the sub-nozzle air supply system 20 includes a sub-nozzle air booster 20a for sucking air from the atmosphere and increasing the pressure to a predetermined pressure, and a sweep nozzle at the outlet of the sub-nozzle air booster 20a. The sub-nozzle air supply line 20g connected to the sub-nozzle 38, the buffer tank 20b disposed downstream of the sub-nozzle air booster 20a in the sub-nozzle air supply line 20g, and the shutoff valve sequentially disposed downstream of the buffer tank 20b 20c, check valve 20d, orifice 2
0f, the flow regulating valve 20e.

In the present embodiment, the power generation system 10 is provided with an auxiliary air supply system 30 functioning as a backup for the auxiliary nozzle air supply system 20. The auxiliary air supply system 30 has an auxiliary air supply pipe connected between the outlet of the raw material air pressure booster 26 and the check nozzle 20 d and the orifice 20 f in the auxiliary nozzle air supply line 20 g of the auxiliary nozzle air supply system 20. The passage 30a includes a shutoff valve 30b, a check valve 30c, and a pressure switch 30d which are sequentially arranged from the outlet of the raw material air booster 26 in the auxiliary air supply line 30a. Sub nozzle air supply line 30
a may be connected to the raw air line 26a.

In the following, an example in which the power generation system 10 is a gasification power generation plant using solid fuel, particularly coal will be described in accordance with the procedure for starting the system from a so-called cold state in which the power generation system 10 is completely cooled. The operation of the embodiment will be described.

First, the sub-nozzle air booster 20a is started, and air at a predetermined pressure is passed through the sub-nozzle 36 and the sweep nozzle 38 of the combustor 16d through the sub-nozzle air supply line 20g. After that, the starting speed of the compressor 16a and the turbine 16b is increased to the ignition speed by a starter (not shown). The air supply to the combustor 16d starts with the rotation of the compressor 16a. Next, the starting liquid fuel is supplied from the liquid fuel source to the sub-nozzle 36 via the liquid fuel supply line 32. In the starting liquid fuel, air supplied through the sub nozzle air supply pipe 20g is sprayed as a spray medium, and the sprayed liquid fuel is ignited.

When the starting liquid fuel is ignited, the rotation of the gas turbine generator 16 further increases to reach the rated speed and the warm-up operation is started. During this time, part of the air pressurized by the rotation of the compressor 16a is
The pressure is further increased and supplied to the air separation device 18, where an oxidant and nitrogen gas are generated. The nitrogen gas generated by the air separation device 18 is pressurized by a nitrogen gas pressurizer 24 and is supplied to a nitrogen gas pressurizer outlet line 2.
The gas is supplied to the gasification furnace 12 via 4a, and the start-up process of the gasification furnace 12 is started.

When the oxidizing agent and the nitrogen gas are generated in the air separation unit 18, the pulverized coal is supplied from a pulverized coal supply source including a coal mill (not shown) to a pulverized coal transfer path 28 including a pulverized coal burner of the gasification furnace 12. The pulverized coal is supplied to the gasification furnace 12. At this time, the nitrogen gas generated by the air separation device 18 and pressurized by the nitrogen gas pressurizer 24 as described above is supplied to the pulverized coal transport path 28 via the nitrogen gas pressurizer outlet pipe 24a. The nitrogen gas pressurized by the nitrogen gas pressurizer 24 may be used as a seal gas for the gasification furnace 12. Further, the nitrogen gas pressurized by the nitrogen gas pressure booster 24 is supplied to the gas purification facility 14 and used as a char carrier medium or the like of the gas purification facility 14.

On the other hand, the oxidizing agent generated by the air separation device 18 and pressurized by the oxidizing agent booster 22 is supplied to the gasification furnace 12 through the oxidizing agent booster outlet line 22a.
Through the gasification reaction with the pulverized coal supplied to 2, the fuel gas containing carbon monoxide and hydrogen as main components is generated. The fuel gas generated in the gasification furnace 12 contains a large amount of impurities such as char and sulfur components in addition to carbon monoxide and hydrogen. Therefore, the fuel gas generated in the gasification furnace 12 has such impurities removed in the gas purification facility 14 before being supplied to the gas turbine power generator 16. The gas purification equipment 14 includes a char separation device, a desulfurization device, and the like as conventionally known.

The fuel gas purified by the gas purification facility 14 is supplied to the main nozzle 34 of the combustor 16d via the fuel gas supply line 14a. This fuel gas is supplied to the combustor 16.
At d, the air is mixed with the air from the compressor 16a, burns, and the combustion gas is supplied to the turbine 16b. On this occasion,
Air is supplied from the sub nozzle air supply line 20g to the fuel gas supply line 14a via the line 14b, and the main nozzle 34
May be a premixed flame or a partially premixed flame.

As described above, when the pulverized coal is ignited in the gasification furnace 12, the temperature in the gasification furnace 12 rises, and when the temperature in the gasification furnace 12 reaches a predetermined temperature, the gasification process is stabilized and the starting process is started. Ends. With the end of the starting process, the supply of the starting liquid fuel is cut off. When the starting liquid fuel is shut off, the sub-nozzles 36 are heated by radiant heat from the combustion gas generated in the main nozzles 34. If the starting liquid fuel remains in the sub-nozzle 36, the starting liquid fuel is carbonized and seized on the sub-nozzle 36. In order to prevent this, air is continuously supplied from the sub-nozzle air supply system 20 to the sub-nozzle 36 even after the start-up process is completed, and is used as a purge medium for the sub-nozzle 36. As a result, the starting liquid fuel remaining in the sub-nozzle 36 is removed, and its carbonization is prevented. Further, after the start-up process, air is supplied from the sub-nozzle air supply system 20 subsequent to the sweep nozzle 38, and the sub-nozzle 36 is cooled. After the purge of the sub-nozzle 36 is completed, the air supplied to the sub-nozzle 36 as the purge medium may be stopped or may be continuously supplied. Further, during the start-up process, the supply of air as a sweep medium to the sweep nozzle 38 may be stopped.

When the startup process is completed as described above,
The gas turbine generator 16 transitions to the normal load operation state. During normal operation, exhaust gas from the turbine 16b is, for example, as shown in FIG.
Steam turbine power generation system 10 including steam turbine power generation device 104, condenser 106, and the like as main components
0 can be used as a heat source to form a combined cycle.

As described above, during the normal operation of the power generation system 10, the sub-nozzle 36 continues to supply air from the sub-nozzle air supply system 20 to the sub-nozzle 36 and the sweep nozzle 32 of the combustor 16a. Overheating due to the radiant heat of the combustion gas in the nozzle 34 is prevented. However, the auxiliary nozzle air booster 2 of the auxiliary nozzle air supply system 20
Since 0a is a rotating machine, it is feared that a failure will occur during long-term continuous operation, and the auxiliary nozzle air supply system 20 will stop. When the sub-nozzle air booster 20a stops,
Because the sub nozzle 36 is overheated and damaged, the power generation system 1
0 has to be stopped.

According to the present embodiment, even when the auxiliary nozzle air pressure booster 20a is stopped, air can be supplied to the auxiliary nozzle air supply system 20 by the auxiliary air supply system 30. That is, when the sub-nozzle air booster 20a stops, the pressure in the sub-nozzle air supply pipe 20g decreases. This pressure drop is detected by the pressure switch 30d, and when the pressure in the sub nozzle air supply line 20g decreases to a predetermined pressure value, the shutoff valve 30b is opened, and the compressor 16a, the raw material air booster 26, the auxiliary air supply line 30a
Is supplied to the sub-nozzle air supply line 20g via Connect the buffer tank 20b to the secondary nozzle air supply line 2
0g, the auxiliary nozzle air booster 20a
Is stopped, a sharp drop in pressure in the sub nozzle air supply line 20g is prevented, and the air supply from the auxiliary air supply system 30 can be smoothly shifted to.

Having described the preferred embodiment of the invention,
It is obvious to those skilled in the art that the present invention is not limited to this, and various changes and modifications are possible. For example,
In the power generation system 10 according to the embodiment of FIG. 1, the compressor 16 a of the gas turbine generator 16 is used to supply air as an oxidant raw material to be supplied to the air separation device 18.
Of compressed air or compressor 16a
The raw material air pressure booster 26 for further increasing the pressure of the bleed air was provided. However, the present invention is not limited to this.
That is, in the present invention, the main purpose is to enable the gas having the air pressurized by the compressor 16a of the gas turbine generator 16 to be supplied to the auxiliary air supply system 30 and supply the gas to the auxiliary nozzle air supply system. The gas is not limited to a part of the air pressurized by the compressor 16a or the air further pressurized by the bleed air of the compressor 16a.

In the modified embodiment of the present invention shown in FIG. 3, the raw material air booster 26 of the embodiment shown in FIG. 1 is not provided, and a part of the air at the outlet of the compressor 16a or the bleed air of the compressor 16a is The raw material air to the separation device 18 is supplied directly to the air separation device 18 via a pipe 42. In this configuration, since the pressure of the air in the pipe 42 is insufficient to supply the air to the sub-nozzle air supply pipe 20g, the nitrogen gas pressurization for pressurizing the nitrogen gas as a by-product from the air separation device 18 is performed. The nitrogen gas from the outlet line 24 a of the machine 24 can be supplied to the sub-nozzle air supply system 20. That is, in this embodiment, one end of the auxiliary air supply line 30a of the auxiliary air supply system 30 on the upstream side is connected to the nitrogen gas booster outlet line 24a, and the other end on the downstream side is the auxiliary nozzle air supply line 20g. Is connected between the check valve 20d and the orifice 20f. In the embodiment of FIG. 3, other configurations are the same as those of the embodiment of FIG. 1, and each component corresponding to the embodiment of FIG. 1 is given the same reference numeral.

Further, in the embodiment of FIG. 1, high-purity oxygen gas or oxygen-enriched air generated in the air separation device 18 is used as the oxidizing agent, but the present invention is not limited to this. As shown in FIG. 4, a part of the air at the outlet of the compressor 16a or the bleed air of the compressor 16a is boosted by the booster compressor or the auxiliary compressor 52, and then to the oxidizer booster outlet line 22a via the auxiliary compressor outlet line 52a. It can be supplied and mixed with high-purity oxygen gas or oxygen-enriched air generated by the air separation device 18 and used as an oxidizing agent. In this configuration, the auxiliary air supply line 30 of the auxiliary air supply system 30
is connected to an auxiliary compressor outlet line 52a, and the air pressurized by the auxiliary compressor 52a is pressurized by the compressor 16a of the gas turbine generator 16 to be supplied to the auxiliary air supply system 30. It is used as a gas whose source is the air that has been removed. In the embodiment of FIG. 4, other configurations are the same as those of the embodiment of FIG. 1, and each component corresponding to the embodiment of FIG. 1 is given the same reference numeral.

Further, in the above-described embodiment, an example is shown in which a combined cycle of a gas turbine cycle and a steam turbine cycle is employed. However, the present invention is not limited to this, and is a power generation system including only a gas turbine cycle. You may.

Furthermore, in the above-described embodiment, the case of coal gasification has been described as an example. However, the present invention is not limited to this, and the raw material for gasification is petroleum coke, which is a solid fossil fuel other than coal. Alternatively, it can be an organic substance containing a liquid fossil fuel such as heavy oil. In particular, when a liquid organic substance is used, the nitrogen gas pressurized by the nitrogen gas pressurizer 24 can be used for spraying the liquid fuel instead of the pulverized coal transport medium.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a first embodiment of the present invention.

FIG. 2 is a schematic diagram illustrating an example of a dual combustor.

FIG. 3 is a schematic diagram of another embodiment of the present invention.

FIG. 4 is a schematic view of still another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Power generation system 12 ... Gasification furnace 14 ... Gas purification equipment 16 ... Gas turbine power generator 16a ... Dual combustor 18 ... Air separation device 20 ... Sub-nozzle air supply system 22 ... Oxidizer booster 24 ... Nitrogen gas booster 30 ... Auxiliary air supply system

Claims (4)

[Claims] 1. A gasification furnace for producing a fuel gas by gasifying a solid or liquid organic substance with an oxidizing agent, a gas purifying facility for purifying the produced fuel gas, and a main fuel for producing the fuel gas. A gas turbine power generator, an air separation device that generates the oxidant and nitrogen gas from air, an oxidizer booster that pressurizes the oxidant and supplies it to the gasifier, and pressurizes the nitrogen gas. And a nitrogen gas booster that supplies the gasification furnace or gas purification equipment with the gas turbine power generator, wherein the gas turbine power generator burns a main nozzle for burning the generated gas and a starting liquid fuel. A combustor having a sub-nozzle for causing the at least one of the power generation system to promote atomization of the starting liquid fuel, to cool the sub-nozzle after starting or to purge the sub-nozzle. The gas turbine power generator includes a sub-nozzle air supply system including a sub-nozzle air booster for pressurizing and supplying ambient air to the sub-nozzle for use in one or more applications. A power generation system characterized in that gas having air pressurized by said compressor as a bottom source can be supplied to a sub-nozzle air supply system. 2. The apparatus according to claim 1, further comprising a raw air booster for boosting air boosted by a compressor of the gas turbine generator and supplying the boosted air as raw air to the air separation device. The power generation system according to claim 1, wherein a part of the generated air can be supplied to the auxiliary nozzle air supply system. 3. A part of the air pressurized by a compressor of the gas turbine generator is supplied to the air separation device as raw material air, and nitrogen gas separated and generated from the raw material air in the air separation device is The power generation system according to claim 1, wherein the power can be supplied to the auxiliary nozzle air supply system. 4. An auxiliary compressor for further increasing the pressure of the air pressurized by the compressor of the gas turbine generator and supplying the air together with the oxidant generated by the air separation device to the gasification furnace, The power generation system according to claim 1, wherein a part of the air pressurized by the auxiliary compressor can be supplied to the auxiliary nozzle air supply system.