JPS6385224A - Gas turbine plant which uses, as fuel, generation gas from gasified solid fuel - Google Patents

Abstract

PURPOSE:To contrive to miniaturize a title device by forming a gasification device in two-tower type comprised of a reactor and a combustor and mixing generation gas and combustion gas, which are generated from each furnace, after cleaning only the combustion gas so as to use as fuel for a gas turbine. CONSTITUTION:A reactor 11 which forms a fluidized bed by solid fuel and fluidized medium and generates generation gas by gasifying the solid fuel under pressure application and a fluidized bed type combustor 12 which heats the fluidized medium under pressure application are provided in a pressure vessel 16. And generation gas gasified in the reactor 11 is sent out through two-stages, back and forth, cyclones 13, 14 and combustion gas from the combustor 12 is introduced into a heat exchanger 17 through a cyclone 15 and sent out to a cleaning tower 18 after being heated. Next the combustion exhaust gas after heating is mixed with generation gas from the cyclone 14 and supplied to a combustor 26 as generation gas low in dust concentration and a gas turbine main body 23 is driven by high pressure gas generated by combusting generation gas.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention gasifies a solid fuel containing coal, wood, or low-grade coal such as peat or brown coal by pyrolysis or the like, and uses the resulting gas as a fuel. The present invention relates to a gas turbine plant.

[Conventional technology]

In recent years, from the perspective of energy diversification, gas turbine plants have been proposed that gasify coal and other solid fuels through pyrolysis and use the resulting gas as fuel to generate electricity. A combined power generation plant that combines the following has been proposed.

[Problem that the invention seeks to solve]

However, the generated gas usually contains solid components such as char and tar components that are by-produced by reactions such as thermal decomposition. If this produced gas containing solids is combusted and introduced into the gas turbine, it will cause various troubles in the gas turbine system, so it must be removed before flowing into the gas turbine system.

However, if the solid content is removed by a dry dust collection method under normal pressure, there is a problem in that the apparatus becomes extremely large.

On the other hand, the wet dust collection method has the feature that the equipment can be made smaller, but the sensible heat retained in the produced gas heated to high temperature in processes such as pyrolysis is wasted, which reduces the thermal efficiency of the plant. The problem is that it is significantly reduced.

An object of the present invention is to provide a gas turbine plant using solid fuel gasification product gas as fuel, which can downsize the device and remove dust from the product gas without significantly reducing thermal efficiency. be.

[Means for solving problems]

In order to achieve the above object, the present invention provides a reactor that forms a fluidized bed with a solid fuel and a fluidized medium, gasifies the solid fuel under pressure, and generates a product gas, and a reactor that heats the fluidized medium under pressure. A layered combustor, a pressure vessel in which at least the reactor and the combustor are stored and maintained at the same internal pressure, and solid particles containing unburned components in the generated gas sent out from the reactor are separated and collected. a first gas-solid separator that separates and collects solid particles in the combustion gas sent out from the combustor and supplies it to the reactor; a cleaning tower that cleans the combustion gas sent out from the gas-solid separator of No. 2;
a heat exchanger that heats the cleaning combustion gas sent out from the cleaning tower by exchanging heat with the combustion gas; and a heat exchanger that heats the cleaning combustion gas sent out from the cleaning tower, and the cleaning combustion gas heated by the heat exchanger and the cleaning combustion gas sent out from the first gas-solid separator. A gas turbine that uses a gas mixed with generated gas as fuel.

[Effect]

With this configuration, unburned components (such as char) in the generated gas separated by the first gas-solid separator and solid particles in the fluidized medium are guided to the combustor, where the unburned components are transferred to the actor. It is burned to produce the energy needed to gasify the supplied raw material (such as coal). The fluidized medium heated by the combustion is accompanied by the combustion gas and
It is separated and collected in a gas-solid separator. The separated fluidized medium is then supplied to the actuator, forms a fluidized bed together with the raw material, and supplies the energy necessary for gasification. That is, part of the thermal energy generated in the combustor is indirectly applied to the reactor via the fluid medium.

On the other hand, the combustion gas is led to the heat exchanger via the first gas-solid separator, and then washed with water in the washing tower, and fine solid particles (
dust), etc. are cleaned and removed, resulting in purified cleaned combustion gas. The cleaned combustion gas is reheated in a heat exchanger and mixed with the product gas exiting the first gas-solid separator. This dilutes and reduces the solid particle concentration (hereinafter referred to as dust concentration) in the generated gas. The generated gas, whose dust concentration has been diluted in this way, is led to the gas turbine unit, where it is combusted in the combustor using high-pressure combustion air supplied from the air compressor, and the combustion gas is supplied to the gas turbine as a working fluid. be done.

That is, the present invention separates and removes dust from the produced gas flowing out of the reactor using a dry method, and on the other hand, processes the combustion gas flowing out from the combustor using a dry method and then further performs a wet cleaning treatment, and then mixes them. It is used as fuel for gas turbines. Therefore, by significantly reducing the amount of gas to be wet-processed, the equipment can be downsized, and heat can be recovered by reheating the cleaning combustion gas with the combustion gas flowing into the cleaning tower. By mixing the gas into the produced gas, the dust concentration of the produced gas is reduced, and the necessary dust removal is sufficiently achieved without significantly reducing thermal efficiency.

〔Example〕

Hereinafter, the present invention will be explained based on an embodiment. 6 Fig. 1 shows an overall configuration diagram of a gas turbine combined cycle plant having a gas turbine plant as a main part according to an embodiment to which the present invention is applied.

In FIG. 1, the solid fuel gasifier 10 is of a two-unit type, each having a fluidized bed type glue actor 11 and a combustor 12, and each furnace has fluidized sand as a fluidized medium. It is loaded. Note that it is also possible to use a catalyst or the like as the fluid medium, if necessary.

In the reactor 11, raw materials such as coal are supplied to the bottom of the furnace, and heated fluidized sand is supplied from the combustor.

A fluidized bed is formed using oil and steam supplied from a steam turbine, which will be described later, as a fluidizing medium, and one coal is gasified by reactions including thermal decomposition using the heat retained in the fluidized sand. The generated gas is extracted from the top of the furnace, and relatively large solid particles (char and fluidized sand) entrained in the generated gas are separated and collected in the cyclone 13 as a first gas-solid separator. Furthermore, fine solid particles (fly ash) are separated and collected in the cyclone 14. The fly ash separated and collected by the cyclone 14 in the latter stage is discharged outside the system, and the char and fluidized sand separated and collected by the cyclone 13 in the former stage are circulated and supplied to the bottom of the combustor 12. There is.

In the combustor 12, a fluidized bed is formed by the char and fluidized sand supplied from the cyclone 13 and air extracted from an air compressor (described later), and unburned components such as char are burned to heat the fluidized sand. It looks like this. The combustion gas is extracted from the top of the furnace, and relatively large particles of fluidized sand are separated and collected in a cyclone 15. The fluidized sand separated and collected by the cyclone 15 is circulated and supplied to the bottom of the reactor 11 again.

As mentioned above, Actor 11, Combustor 12, Cyclone 1
3. ．． 14 and 15 are stored in the pressure vessel 16,
The inside of this pressure vessel 16 is maintained at a predetermined pressure (for example, 25 kg).
/at), the reactor 11 and combustor 12 are operated under pressure. Note that the pressurizing medium of the pressure vessel 16 can be maintained by sealing bleed air from an air compressor.

Combustion gas flowing out from the pressurized gasifier 1o configured as described above is led to the cleaning tower 18 via the heat exchanger 17, where the cleaning liquid injected from the cleaning liquid pump 19 is added to the combustion gas. The fine particles contained therein are washed away. The cleaned combustion gas purified by this cleaning is pressurized by the booster 21 and then led to the heat converter 17, where it is reheated by high-temperature combustion gas and then combined with the generated gas flowing out from the cyclone 14. The mixture is mixed and supplied to the gas turbine unit 22.

The gas turbine unit 22 includes a gas turbine main body 23, an air compressor 24 and a generator 25 connected to the gas turbine main body 23, and a combustor 26 that generates working fluid for the gas turbine main body 23. The above-mentioned mixed gas of generated gas and cleaning combustion gas is combusted in the combustor 26 by high pressure air for combustion supplied from the air compressor 24, and the combustion gas is supplied to the gas turbine main body 23.
to drive. Exhaust gas flowing out from the gas turbine main body 23 is discharged from a stack (not shown) via a waste heat boiler 30.

The waste heat boiler 30 heats the feed water supplied from the feed water pump to generate steam, supplies the steam to the steam turbine 32, and thereby drives the generator 33 connected to the steam turbine 32 to generate electricity. It is supposed to be done. The steam that drives the steam turbine 32 is condensed in a condenser 34, and the condensed water is circulated to the waste heat boiler 30 by a feed water pump 31.

Note that the air discharged from the air compressor 24 is passed through the air cooler 37 and the booster compressor 38 to the combustor 12 described above.
The air is supplied as combustion air for the air and as pressurized air for the pressure vessel 16. Further, steam extracted from the middle stage of the steam turbine 32 is supplied as a fluidizing gas to the reactor 11.

The operation of the embodiment configured in this way will be described below.

The two-unit fluidized bed gasifier reactor 11 and combustor 12 housed in the pressure vessel 16 are each operated at high pressure (for example, 251 ug/d).

The generated gas gasified in the reactor 11 has char and fluidized medium separated and removed in the cyclone 13 at the front stage, and is led to the cyclone 14 at the rear stage. After fine particles of fly ash are removed by a cyclone 14 in the latter stage, the ash is sent out.

On the other hand, the combustion gas flowing out from the combustor 12 is led to a cyclone 15 to remove the fluidized medium, and then led to a cleaning tower 18 via a heat exchanger 17, where fine fixed particles such as dust and tar are removed. are separated and removed at a high rate. The combustion exhaust gas purified by this cleaning is transferred to the heat exchanger 1.
At 7, it is reheated by high-temperature combustion gas and mixed into the generated gas flowing out from the cyclone 14. As a result, the concentration of dust contained in the generated gas is substantially reduced according to its mixing rate, and the generated gas with a low dust concentration is combusted in the combustor 26 to drive the gas turbine body 23 and generate electricity.

The sensible heat of the exhaust gas discharged from the gas turbine main body 23 is recovered by the waste heat boiler 30, and the heat is recovered by the waste heat boiler 30.
drive to get power.

In this way, it is converted into solid fuel gas such as coal,
II'M is generated and used as fuel for a gas turbine, and converted into electric power through gas turbine power generation and steam turbin power generation using a waste heat boiler.

Note that the energy that does not contribute to power generation is the exhaust gas discharged from the waste heat boiler 30 and the heat discharged outside the system by the condenser 34, but this is less than in normal pneumatic power generation and is a power generation plant with extremely high thermal efficiency. Become.

As described above, according to this embodiment, the gasifier fi! i
o is a two-unit system consisting of a reactor 11 and a combustor 12, and among the generated gas and fuel gas generated from these furnaces,
Highly efficient dust removal is achieved by cleaning only the fuel gas, and by mixing the purified cleaned fuel gas with the generated gas, the dust concentration of the fuel gas supplied to the gas turbine unit is substantially reduced. This makes it possible to make the equipment more compact than when dry-type dust collection is performed on the fuel of the generated gas and combustion gas, and on the other hand, the thermal efficiency is improved compared to when the entire amount of generated gas and combustion gas is treated with wet-type dust collection. As a result, the device can be made smaller and the desired dust removal can be achieved without significantly reducing efficiency.

Note that FIG. 2 shows an example of the dust tolerance range of a gas turbine. According to this, the tolerance range is determined as a correlation between dust particle size and concentration, and it is not sufficient to remove only relatively large particle size dust; it is also necessary to remove fine dust particles. It shows. This shows that dry dust collection using only a cyclone, which cannot remove fine dust, is insufficient.

In addition, in the above embodiment, the dust concentration is substantially reduced by mixing the combustion gas with the flammable produced gas, so the calorific value of the produced gas is reduced. This does not necessarily lead to a reduction in the overall thermal efficiency, i.e., if the produced gases were led separately to the gas turbine unit without mixing them, while the combustion gases could be separated by driving e.g. an expansion turbine, If electricity is to be generated, the calorific value of the produced gas is too high, so when applying to a standard gas turbine where the turbine inlet temperature is fixed, the combustion gas temperature of the combustor should be adjusted to that temperature (e.g.
1. Dilution air is required to maintain the temperature at OOO”C).This dilution air is normally supplied from an air compressor, but for this purpose the capacity of the air compressor must be made larger than the standard one. Not only does it have to be done, but it also requires extra power. Therefore, in a system that uses a gas turbine and an expansion turbine without mixing the produced gas and fuel gas, an extra expansion turbine and the like are required. , cannot necessarily be said to be advantageous in terms of thermal efficiency.In particular, in the case of a pressurized gasifier, the dust concentration in the produced gas is relatively high compared to an ordinary pressure type gasifier, so the above effect is It becomes remarkable.

Furthermore, according to the above embodiment, the reactor 11 and the combustor 12 are housed in the pressure vessel 16, and by pressurizing the inside of the pressure vessel 16, it is possible to operate at high pressure. Since the structures of the reactor 11 and combustor 12 are no different from those of the normal pressure type, there is no problem with the strength of the materials that constitute them.

In addition, according to the above embodiment, since the gasifier is a two-unit type gasifier, when the generated gas has a high calorific value and the required amount of fuel consumed by the gas turbine unit is small, it can be mixed with the combustion gas. It is also possible to provide a branch valve 36 upstream of the mixing point, so that the fuel can be used as another fuel source, such as city gas, for example. That is, according to this embodiment, a multipurpose combined power generation plant can be achieved.

〔Effect of the invention〕

As explained above, according to the present invention, the gasification apparatus is a two-unit type consisting of a reactor and a combustor, and only the combustion gas of the generated gas and combustion gas generated from each furnace is cleaned. Afterwards, since both are mixed and used as fuel for the gas turbine, the device can be downsized and the desired dust removal can be achieved without reducing thermal efficiency.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of a gas turbine combined cycle power plant to which an embodiment of the present invention is applied, and FIG. 2 is a diagram showing the permissible range of dust concentration at the inlet of the gas turbine. 10... Gasifier, 11... Reactor, 12... Combustor, 13.14
．． 15... Gas-solid separator, 16... Pressure vessel, 17... Heat exchanger, 18...
...Cleaning tower, 23... Gas turbine main body,
26... Combustor.

Claims (1)

[Claims] (1) A reactor that forms a fluidized bed with solid fuel and a fluidized medium, gasifies the solid fuel under pressure, and generates a generated gas, and a fluidized bed combustor that heats the fluidized medium under pressure, at least the reactor and the combustor are stored,
a pressure vessel maintained at the same internal pressure; a first gas-solid separator that separates and collects solid particles containing unburned components in the generated gas sent out from the reactor and supplies the combustor to the combustor; a second gas-solid separator that separates and collects solid particles in the combustion gas sent out from the reactor, and a cleaning tower that cleans the combustion gas sent out from the second gas-solid separator; , a heat exchanger that heats the cleaned combustion gas sent out from the cleaning tower by exchanging heat with the combustion gas, and a heated cleaning combustion gas heated by the heat exchanger and the cleaned combustion gas sent out from the first gas-solid separator. A gas turbine plant that uses solid fuel gasification product gas as fuel, the gas turbine plant that uses solid fuel gasification product gas as fuel, comprising: