JPH0421045B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a coal gasification combined cycle power plant, and more specifically, the present invention relates to a coal gasification combined cycle power plant, in which air or oxygen as a gasifying agent is installed at the outlet of a steam generator at the outlet of a gasifier. Coal gasification is ideal for reducing plant costs by improving thermal efficiency and improving gas turbine operability by exchanging heat with the gas produced by the gasifier after removing dust using a precision dust removal device. Regarding combined cycle power plants.

[Background of the invention]

Figure 1 shows the heat cycle of a conventional coal gasification combined cycle power plant.

As will be explained in detail later, the combined power generation plant 61
A coal gasification plant 60 (indicated by a dashed-dotted line) is composed of a gas turbine 17, an exhaust heat recovery boiler 20, a steam turbine (high-pressure turbine 42, medium-low pressure turbine 43), etc.
is composed of a coal gasifier 3, a gasifier outlet steam generator 7, a gas purifier 11, etc., which are combined as a heat cycle to form a combined coal gasification combined power generation plant.

Air or oxygen 2 is supplied into the coal gasifier 3 as a gasifying agent for gasifying the coal 1,
The gasifier crude gas 4 generated is supplied to a gas turbine 17 as a fuel gas 13. fuel gas 1
3, since the pressure of the gas turbine combustor 14 is 10 ata to 20 ata (absolute pressure), it is desirable that the gasifying agent 2 is pressurized and supplied to the coal gasifier 3. When air extracted from the gas turbine compressor 15 and compressed by the booster compressor 59 is used as the gasification agent 2, the lower the air temperature, the less power is required to boost the pressure. On the other hand, the higher the supply temperature of the gasifying agent 2, the more the gasifying agent 2 increases in the coal gasifier 3.
The amount of heat required to raise the temperature of the plant is small, and the thermal efficiency of the plant can be increased. In the conventional technology, air from the gas turbine compressor 15 (corresponding to the gasifying agent 2, hereinafter also referred to as air 2) is cooled by a bleed air cooler 57, and after being pressurized, it is supplied to the coal gasifier 3. As a result, the air supply temperature is low, which reduces the thermal efficiency of the plant as described above, and the supply amount of air 2 increases, resulting in the disadvantage that the air balance in the gas turbine compressor 15 is disrupted.

The prior art will be explained in more detail below.

First, the combined power generation plant 61 will be explained. Air 16 introduced into the gas turbine compressor 15 is compressed and supplied to the gas turbine combustor 14, which burns the fuel gas 13 supplied to the gas turbine combustor 14, and the gas turbine 1 is heated with the generated high-temperature gas.
7 is activated, and the gas turbine generator 18 generates electrical energy. Further, the gas turbine outlet exhaust gas 19 is recovered to the exhaust heat recovery boiler 20.

The exhaust heat recovery boiler 20 includes a low pressure economizer 21, a low pressure drum 22, a low pressure evaporator 23, a high pressure economizer 24,
It is composed of a high-pressure drum 25, a high-pressure evaporator 26, a superheater 27, a reheater 28, and the like.

The condensate 40 is pressurized by a water supply pump 41 and is supplied to the low pressure economizer 21 . That is, the feed water pump outlet water supply 39 is preheated by exchanging heat with the gas turbine bleed air 56 from the gas turbine compressor 15 and the bleed air cooler 57, and then is sent to the exhaust heat recovery boiler 20.
(indicated by →).

The exhaust heat recovery boiler feed water 37 branches into the low pressure drum 22, the gasifier steam generator feed water 30, and the feed water pump inlet water feed 29 at the outlet of the low pressure economizer 21.
The water supply pump inlet water supply 29 is connected to the high pressure water supply pump 38
After being pressurized, the water is branched into a high-pressure economizer inlet water supply 33 and a gasifier outlet steam generator water supply 32.
The high-pressure economizer inlet feed water 33 is sent through the high-pressure economizer 24 to the high-pressure drum 25 to generate steam.
On the other hand, the gasifier outlet steam generator feed water 32 is sent to the gasifier outlet steam generator 7 (denoted by ), which will be described later. Further, the gasifier steam generator feed water 30 is sent to the steam generator 54 of the coal gasifier 3 (indicated by ).

The steam generated in the high pressure drum 25 is transferred to the superheater 27
The high pressure turbine 42 generates heat and performs work in the high pressure turbine 42. Further, the steam that has done work is heated in a reheater 28 together with the steam generated in the low pressure drum 22, and is sent to a medium and low pressure turbine 43 to do work, and together with the high pressure turbine 42, a steam turbine generator 45 generates electrical energy. The steam that has passed through the steam turbine 43 is cooled in a condenser 44 and becomes condensate 40, which is then turned into water supply 39 at the water supply pump outlet by the water supply pump 41.

Next, the coal gasifier 3 of the coal gas plant 60
The gasification agent 2 supplied to the gas turbine compressor 15 includes gas turbine bleed air 5 extracted from the gas turbine compressor 15.
6 is cooled by a bleed air cooler 57, used as booster compressor inlet air 58, and this is pressurized by a booster compressor 59, which has been generally used in the past. This is due to the following reason.

When using air as the gasifying agent 2, the amount of air supplied for gasification is generally 2 times the amount of input coal 1.
It will be 3 times as heavy. Moreover, the supply pressure of the fuel gas 13 supplied to the gas turbine combustor 14 is
15ata to 25ata, and two methods are used for this compression method. One is to set the pressure in the coal gasifier 3 to normal pressure and increase the pressure of the generated gas after gasification, and the other is to pressurize the coal 1 and gasification agent 2 to generate coal gas. Chemical furnace 3
In this method, the gas is supplied to the gas turbine combustor 14 after being gasified under pressure.

Regarding the method of pressurizing the generated gas, since the generated gas contains sulfur compounds and dust, it is necessary to pressurize the purified gas after gas purification. Since the gas purification device 11 operates at low pressure, the capacity of the device is larger than that of the pressurized coal gasifier 1; and in gas purification, especially wet gas purification, gas absorption is generally It increases in proportion to the pressure, so
Since it is necessary to absorb gas with a large amount of absorbent, the capacity for gas purification and the amount of utility used increase;
It has a larger capacity than air or oxygen, which is The system for supplying the fuel gas 13 to the turbine combustor 14 is also thermally efficient.
It has now been discovered that this method is also superior in terms of reducing device capacity.

Furthermore, in the case of pressurized gasification, as shown in FIG. Therefore, the power required to compress the gasifying agent 2 can be reduced compared to the case where work is done using the electrical output generated by the gas turbine generator 18 and the steam turbine generator 45.

For the reasons mentioned above, the gasifying agent 2 is pressurized and supplied to the coal gasifier 3 to gasify the coal 1. The generated gasifier crude product gas 4 is introduced into the gasifier outlet steam generator 7, exchanges heat with the gasifier outlet steam generator feed water 32 described above, and is cooled. The cooled steam generator outlet crude gas 8 is introduced into a gas/gas heat exchanger 9 and exchanges heat with purified gas 12 sent out from a gas purification device 11.
The gas purifier 1 is cooled to the temperature required for gas purification and is used as crude gas 10 at the outlet of the gas/gas heat exchanger.
1 will be introduced. The purified gas 12 is, as described above,
After being heated in the gas/gas heat exchanger 9, it is supplied as a fuel gas 13 to the gas turbine combustor 14,
After combustion, the high-temperature gas performs work in the gas turbine 17 and causes the gas turbine generator 18 to generate electrical energy.

Further, the temperature of the gasifier crude gas 4 varies depending on the type of coal gasifier 3 used, but is generally about 900° C. or higher. On the other hand, gasifier crude gas 4
It is necessary to purify the gas 4 to prevent corrosion of the gas turbine 17 and for environmental reasons. Therefore, it is necessary to cool the gasifier crude gas 4 to a temperature required for the gas purifier 11. The temperature required for this gas purification varies depending on the type of gas purification used, but can be roughly divided into two types.

In dry gas purification, which involves high-temperature dedusting and desulfurization using an iron oxide adsorbent, the temperature is approximately 450°C.
On the other hand, in wet gas purification in which dust is removed in a water washing tower and desulfurization is performed using an organic solvent absorbent, the temperature required for gas purification 11 is about 100°C. However, since dry desulfurization has no actual results and is currently under development, wet gas purification is generally used as the gas purification device 11 of a coal gasification combined cycle power plant.

Therefore, the gasifier crude gas 4 at about 900℃ is 100
℃ gas/gas heat exchanger outlet raw gas 10 is introduced into the gas purification device 11. The sensible heat represented by this temperature difference heats the fuel gas 13 supplied to the gas turbine combustor 14 to an appropriate temperature, and
As described above, the heat is recovered as a heat source for the exhaust heat recovery boiler 20. The greater the amount of heat recovered, the better the thermal efficiency of the plant will be (approximately 0.2% improvement in thermal efficiency per 100°C increase in fuel gas temperature).

On the other hand, the fuel gas 1 at the inlet of the gas turbine combustor 14
The third temperature is approximately 100° C. to 400° C. due to the heat-resistant temperature limit of a combustion control device (not shown). or,
The temperature of the raw gas 8 at the outlet of the steam generator is approximately 50° higher than the temperature of the fuel gas 13 at the inlet of the gas turbine combustor 14.
It is normal to select a high temperature. Therefore, on the exhaust heat recovery boiler 20 side, the amount of heat with a temperature difference of about 750°C to 450°C cannot be recovered, and as mentioned above, it is necessary to effectively recover this sensible heat in order to improve the thermal efficiency of the plant. Ru.

The higher the supply temperature of the air 2, which is the gasifying agent supplied to the coal gasifier 3, the lower the amount of heat required for gasification in the coal gasifier 3, and the faster the gasification Since the calorific value of the furnace crude gas 4 can be increased, the thermal efficiency of the plant can be improved. However, as described above, the air 2 needs to be pressurized before being supplied to the coal gasifier 3, and in order to reduce the pressurizing power, it is necessary to lower the temperature of the air 2. That is, as described above, it is better to use the gas turbine compressor 15 for compressing the air 2 for the gasification agent as much as possible in terms of thermal efficiency. Normal outlet pressure is 10 ata to 20 ata. On the other hand, the pressure in the coal gasification furnace 3 is set at 10% from the gas turbine combustor 14 in order to ensure the pressure loss in the system from the coal gasification furnace 3 outlet to the gas turbine combustor 14 and the adjustment pressure of the flow rate adjustment valve, etc. No
It is common to use a high pressure of 30ata. Therefore,
It is necessary to further boost the pressure of the gas turbine compressor bleed air 56 and supply it to the coal gasifier 3, but the power of this booster compressor 59 is proportional to the volumetric flow rate of the air to be pressurized, that is, the temperature of the air to be pressurized is Low power means less power. Normally, in order to reduce the power of this boost compressor 59, the boost compressor 59
The air at the inlet is cooled by a bleed air cooler 57,
By reducing the volumetric flow rate, the power of the boost compressor 59 is reduced.

As a result, the supply temperature of air 2, which is a gasification agent, to coal gasifier 3 decreases, and the efficiency of converting coal into combustible components and cold gas efficiency in coal gasifier 3 decreases, reducing the overall plant efficiency. There is a problem that fuel efficiency decreases. Furthermore, since the temperature of air 2, which is a gasifying agent, is low, it is necessary to burn extra carbon in the coal in order to raise the temperature of the gasifying agent to the gasification temperature. The amount of air supplied increases, and the air balance in the gas turbine compressor 15 is disrupted. FIG. 2 shows the relationship between air preheating temperature and gas turbine extraction rate. As the air preheating temperature decreases, the amount of gasifying agent used increases, so the gas turbine extraction rate increases. With the technology that is an extension of the current gas turbine compressor 15, it is necessary to keep the extraction rate of the gas turbine at about 30% or less due to the problem of flow balance of the gas turbine compressor 15, and it is stable even with a large amount of extracted air. A gas turbine compressor 15 that can ensure reliable operation has not yet been developed.

From the above, heating the supply temperature of air 2 as a gasifying agent to the coal gasifier 3 at the outlet of the boost compressor 59 to avoid increasing the power of the boost compressor 59 improves the thermal efficiency of the plant. It can be seen that this method is also effective in terms of improving the operability of the gas turbine.

As a method of heating the air 2 as a gasifying agent to the coal gasifier 3, a method of exchanging heat with the gas turbine exhaust gas 19 and raising the temperature has been proposed in EPRI-AP-1429, etc., but this system First, the pressure of the gas turbine outlet exhaust gas 19 is approximately atmospheric pressure, whereas the pressure of the air on the side to be heated is 10
In order to withstand the differential pressure between the two,
The wall pressure of the tube or plate of the heat exchanger increases, the pressure heat coefficient worsens, and the heat transfer area increases;
Second, since the waste heat recovery boiler 20 and the coal gasifier 3 are generally located apart, the heated high-temperature air piping becomes long, and the weight of high-temperature-resistant alloy steel increases, making it less economical. It has the disadvantage of not being accurate.

Furthermore, when an air preheater is installed on the exhaust heat recovery boiler 20 side, the air preheating temperature is limited by the exhaust gas temperature of the gas turbine 17, and therefore there is a limit to the improvement of thermal efficiency.

Therefore, in order to improve the economic efficiency of the plant, there has been a need for a system that uses as little high-temperature piping material as possible to preheat the temperature of the air supplied to the coal gasifier 3 as high as possible.

[Purpose of the invention]

The present invention was devised to solve the above-mentioned drawbacks and meet the above-mentioned demands, and its purpose is to improve the thermal efficiency of a plant, improve operability, and reduce plant costs. Our goal is to provide a combined cycle power generation plant.

[Summary of the invention]

In order to achieve the above object, the present invention cools the crude gas from the coal gasifier and supplies the gas to the downstream side of the gasifier outlet steam generator that supplies steam to the exhaust heat recovery boiler side. A precision dust removal device is provided to precisely remove dust from the raw gas from the steam generator at the outlet of the coalifier, and a gasification agent supplied to the coal gasification furnace and the precision dust removal device are installed downstream of the precision dust removal device. A gas/gas heat exchanger is provided for exchanging heat with the generated gas dedusted by the dust device and preheating the gasification agent,
and the gas/gas heat exchanger and the gas turbine side of the combined power generation plant are connected, and the gas/gas heat exchanger is provided with a gasifying agent passage for supplying the gasifying agent from the gas turbine side, This coal gasification complex plant is characterized by preheating the gasifying agent supplied to the coal gasifier.

[Embodiments of the invention]

Embodiments of the present invention will be described below based on the drawings.

First, the outline of this embodiment will be explained with reference to FIG.

In the figures, the same reference numerals as in FIG. 1 indicate the same parts or parts with the same function.

A precision dust removal device 63 is provided downstream of the gasifier outlet steam generator 7 of the coal gasification plant 60, and further downstream thereof a gas/gas heat exchanger 9 is provided.
A is provided. Also, gas/gas heat exchanger 9
A gasifying agent passage 83 connecting the gas turbine compressor 15 and the gas turbine compressor 15 is provided.

The steam generator outlet raw gas 8 from the gasifier outlet steam generator 7 is dedusted to discharge dust 65, and is introduced into the gas/gas heat exchanger 9a. On the other hand, inside the gasification agent passage 83, there is a bleed air cooler 57 that cools the gas turbine bleed air 56, which is the gasification agent extracted from the gas turbine compressor 15, and a bleed air cooler 57 that boosts the pressure of the cooled boost compressor inlet air 58. A boost compressor 59 is interposed. Pressurized air 2
is introduced into the gas/gas heat exchanger 9a, exchanges heat with the produced gas 66 at the outlet of the precision dust removal device, is preheated, and is supplied to the coal gasifier 3. As a result, the coal gasifier 3 is supplied with pressurized and preheated air 2 serving as a gasifying agent.

This example will be explained in more detail below.

Conventionally, the steam generator outlet crude gas 8 from the gasifier outlet steam generator 7 contains a large amount of high-temperature dust and corrosion products, so the temperature of the steam generator outlet raw gas 8 is about 350°C. The gas/gas heat exchanger 9 has not been put into practical use only up to a temperature range of 100 to 100% due to thinning due to erosion. Therefore,
In this embodiment, the crude gas 8 at the outlet of the steam generator cooled to approximately 450°C to 600°C by the steam generator 7 at the outlet of the gasifier is dedusted by the precision dust remover 63, resulting in a clean exit from the precision dust remover. A generated gas 66 is introduced into the gas/gas heat exchanger 9a. Note that the removed dust 66 is discharged to the outside of the apparatus.

The gas/gas heat exchanger 9a contains air preheating gas/
A gas heater 64 is provided to heat the air 2 from the gasifier passage 83. The heated air 2 is supplied to a coal gasifier 3. In the conventional technology, the supply temperature of the air 2 supplied to the coal gasifier is approximately 200°C, but with the above method, the supply temperature can be increased to approximately 600°C, and the thermal efficiency can be improved by approximately 8%.

The produced gas that has passed through the gas/gas heat exchanger 9a is introduced into the gas/gas heat exchanger 9, cooled, and sent to the gas purification device 11, as in the prior art. Next, the precision dust removal device 63 will be explained. As the precision dust removal device 63, a granular type dust collection device shown in FIG. 4 is adopted. The granular dust collector is
A temperature-resistant filter agent 77 is attached to a wire mesh 75 and a louver 74.
As shown by the dotted arrow, the packed layer consisting of the filter agent 77 is filled with the filter agent 7
6 is supplied from above, moves downward, and is extracted from the bottom as a filter agent 78 containing dust and discharged. Dirty gas 72 such as crude gas 8 at the outlet of the steam generator is dedusted when passing through a packed bed of filter agent 77 and sent to the next process as dust removal gas 73. As described above, by introducing the steam generator outlet crude gas 8 whose temperature has been lowered to the temperature range of alloy steel in the gasifier outlet steam generator 7 into the above-mentioned granular type dust collector, the precision dust remover Dust in the outlet generated gas 66 is reduced to 5 mg/Nm ³ to 30
mg/Nm ³ , and erosion due to dust can be reduced, and as described above, the air 2 can be preheated by the gas/gas heat exchanger 9a.

As described above, the gasifying agent passage 83 is formed by connecting the gas turbine compressor 15 and the gas/gas heat exchanger 9c, and the bleed air cooler 5 is provided between the gas turbine compressor 15 and the gas/gas heat exchanger 9c.
7 and a boost compressor 59 are provided. As described above, the air 2 as a gasifying agent is pressurized and sufficiently preheated, and then is supplied to the coal gasifier 3.

In the conventional technology, when an air preheater is provided for the air 2 on the exhaust heat recovery boiler 20 side, the temperature of the gas turbine outlet exhaust gas 19 is about 550°C, so the air 12 can only be preheated to about 500°C at most, which reduces thermal efficiency. The degree of improvement is small.

FIG. 5 shows another embodiment of the invention. In the figures, parts with the same reference numerals as in FIGS. 1 and 3 indicate the same parts or parts with the same function.

This embodiment is constructed by connecting a gasifier passage 83 with a bypass passage 84 that branches off from it and communicates directly with the coal gasifier 3, and a bypass flow rate adjustment valve 80 is interposed in the bypass passage 84. be done.
With the above configuration, the coal gasifier 3 is supplied with mixed air of the air 2 preheated via the gas/gas heat exchanger 9a and the air 2 directly introduced from the boost compressor 59 without being preheated. , it becomes possible to control the supply air temperature to a constant value.

Generally, the basic control of the coal gasifier 3 is to supply the gasifying agent 2 at a constant ratio to the input amount of the coal 1, but if the temperature of the gasifying agent 2 fluctuates, The amount of heat required to raise the nitrogen in the gasifying agent 2 to the gasification temperature fluctuates, and the composition of the gasifying agent crude gas 4 changes, so it is necessary to maintain the temperature of the gasifying agent 2 at a nearly constant value. be. According to this embodiment, constant temperature maintenance control can be easily performed.

That is, during normal operation, by controlling the flow rate of the bypass air 79, the supplied air temperature can be controlled to be constant. In addition, when the load suddenly increases, the bypass flow rate adjustment valve 80 is fully opened to supply a large amount of air 2 directly to the coal gasifier 3, eliminating the time delay in the amount of supplied air and improving operability. .

FIG. 6 displays yet another embodiment of the invention.

In the figures, parts with the same reference numerals as in the above embodiments indicate the same parts or parts with the same function.

In this embodiment, a gasifying agent preheater for preheating the gasifying agent 2 is interposed in the middle of the gasifying agent passage 83, and more specifically, a gas turbine heated on the exhaust heat recovery boiler 20 side is installed. The exhaust heat recovery boiler air preheater 81 is connected to the boost compressor 59 and the gas/gas heat exchanger 9a.
(indicated by ).

Air 2, which is a gasifying agent, is pressurized by a boost compressor 59, then preheated by a gas turbine exhaust heat recovery boiler air preheater 81, and sent to an air preheating gas/gas heater 64.

The improved value of thermal efficiency in this embodiment is the same as in the above embodiment, but by dividing the air preheater, a well-balanced system configuration can be achieved.

As described above, the air 2 is heat-exchanged with the produced gas at the outlet of the precision dust remover, which has been removed by the precision dust remover 63 installed on the downstream side of the gasifier outlet steam generator 7,
Since the gasifier air in the gasifier can be preheated to a high temperature, thermal efficiency can be improved.

Furthermore, since the gas/gas heat exchanger 9a for air preheating can be installed near the coal gasifier 3, the number of high-temperature piping after air preheating can be reduced, and plant costs can be reduced. .

Furthermore, as described above, by providing the bypass flow rate regulating valve 80, it is possible to improve the drivability.

FIG. 7 shows the improvement in thermal efficiency according to the above embodiment (indicated by straight line A). The outlet air temperature of the boost compressor 59 is approximately 200°C, and the gas/gas heat exchanger 9a
Since the temperature is preheated to approximately 600°C, an 8% improvement in thermal efficiency, which corresponds to a temperature difference of 400°C, can be measured (indicated by the dotted line in the figure).

Figure 8 shows a typical layout of a coal gasification combined cycle power plant.

When preheating air in the exhaust heat recovery boiler 20, the high-temperature piping after preheating is 350 m to 500 m, but in this embodiment, the air heating gas/gas heater 64 is placed near the coal gasification furnace 3. Because it can be installed, the piping length after preheating can be shortened to approximately 40m. As a result, the connecting piping from the boost compressor 59 to the coal gasifier 3 can be made of carbon steel instead of alloy steel, and because the temperature is low, the volumetric flow rate can be reduced to about 1/2, so the pipe diameter can be reduced. We were able to reduce this by approximately 30%, and by changing the material of this piping, we were able to reduce plant costs by approximately 1 billion yen.

Furthermore, by combining the precision dust removal device 63 of this embodiment with an ultra-high temperature precision dust removal device (not shown) such as a ceramic filter, thermal efficiency can be further improved.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, it is possible to significantly improve the thermal efficiency of a coal gasification combined cycle power plant, and also to significantly reduce plant costs and improve its operability.

[Brief explanation of drawings]

Fig. 1 is a heat cycle configuration diagram of a conventional coal gasification combined cycle power plant, Fig. 2 is a diagram showing the relationship between air preheating temperature and gas turbine extraction rate, and Fig. 3 is a heat cycle diagram of an embodiment of the present invention. Configuration diagram, 4th
The figure is an explanatory diagram showing the main structure of the precision dust removal device used in the embodiment, Figures 5 and 6 are heat cycle configuration diagrams of other embodiments of the present invention, and Figure 7 is the diagram of the heat cycle configuration of the embodiment of the present invention. FIG. 8, a diagram showing the improvement value of thermal efficiency, shows an outline of the plant layout based on this embodiment. 1... Coal, 2... Gasifier, 3... Coal gasifier,
4...Gasifier crude product gas, 5...Gasifier steam generator steam, 7...Gasifier outlet steam generator, 8...
Steam generator outlet crude gas, 9... gas/gas heat exchanger, 10... gas/gas heat exchanger outlet crude gas,
11... Gas purification device, 12... Purified gas, 13... Fuel gas, 14... Gas turbine combustor, 15... Gas turbine compressor, 16... Air, 17... Gas turbine, 18... Gas turbine generator, 19... Gas turbine Outlet exhaust gas, 20...exhaust heat recovery boiler,
21...Low pressure economizer, 22...Low pressure drum, 23...Low pressure evaporator, 24...High pressure economizer, 25...High pressure drum, 26...High pressure evaporator, 27...Superheater, 28...Reheater, 29...Water supply Pump inlet water supply, 30...Gasifier steam generator water supply, 31...High pressure water supply, 32...Gasifier outlet steam generator water supply, 33...High pressure economizer inlet water supply, 34...High pressure steam, 35...Low pressure steam, 3
6... Reheater inlet steam, 37... Exhaust heat recovery boiler water supply, 38... High pressure water supply pump, 39... Water supply pump outlet water supply, 40... Condensate, 41... Water supply pump, 42...
High pressure turbine, 43... Medium and low pressure turbine, 44... Condenser, 45... Steam turbine generator, 54... Steam generator, 56... Gas turbine bleed air, 57... Bleed air cooler, 58... Boost compressor inlet air, 59
...boost compressor, 60...coal gasification plant, 61
...Combined power generation plant, 63...Precision dust removal equipment, 64
...air preheating gas/gas heater, 65...dust,
66... Precision dust removal device outlet generated gas, 72... Dirty gas, 73... Dust removal gas, 74... Louver, 75...
Gold steel, 76, 77...filtering agent, 78...filtering agent containing dust, 79...bypass air, 80...bypass flow rate adjustment valve, 81...garter pin exhaust heat recovery boiler air preheater, 83...gasification agent passage, 84 ...Bypass road.

Claims (1)

[Claims] 1. Appropriate temperature supplied from the coal gasification plant side;
Consists of a gas turbine that operates with fuel gas at an appropriate pressure, an exhaust heat recovery boiler that recovers the exhaust heat of the gas turbine and generates steam, and a steam turbine that operates with the steam from the exhaust heat recovery boiler. A coal gasifier that has a combined power generation plant and gasifies coal with a gasifying agent made of air or oxygen, and cools the crude gas from the coal gasifier,
A gasifier outlet steam generator that generates steam to be supplied to the exhaust heat recovery boiler side, and a gas purifier that refines the crude gas from the gasifier outlet steam generator to form the fuel gas. In a coal gasification combined cycle power plant having the above-mentioned coal gasification plant, the crude gas from the gasifier outlet steam generator is precisely dedusted on the downstream side of the gasifier outlet steam generator. At the same time, a precision dust removal device is provided downstream of the precision dust removal device, and a gas/gasifier is provided on the downstream side of the precision dust removal device to preheat the gasification agent with the generated gas dedusted by the precision dust removal device and supply it to the coal gasification furnace. A gasification agent passage that is provided with a gas heat exchanger, connects the gas/gas heat exchanger and the gas turbine side, and supplies the gasification agent from the gas turbine side to the gas/gas heat exchanger. A coal gasification combined cycle power plant that is characterized by being equipped with. 2 The gasification agent passage connects the gas/gas heat exchanger and the gas turbine compressor that engages the gas turbine, and the gasification agent passage is connected to the gasification agent passage, which connects the gas/gas heat exchanger and the gas turbine compressor that engages with the gas turbine, and connects the gasification agent passage bleed from the gas turbine compressor to an intermediate position. 2. The coal gasification integrated power generation plant according to claim 1, further comprising a booster compressor for boosting the pressure of the agent. 3. Claims characterized in that the gasifier passage has a bypass passage branching from the passage, and the bypass passage is directly connected to the coal gasification furnace via a flow rate regulating valve. The coal gasification combined cycle power plant according to item 1. 4. The gasification agent passage according to claim 1, wherein the gasification agent passage is constructed by interposing a gasification agent preheater for preheating the gasification agent at an intermediate position thereof. Coal gasification combined cycle power plant. 5. The coal gasification integrated power generation plant according to claim 4, wherein the gasification agent preheater is formed by a device that preheats the gasification agent by the exhaust heat recovery boiler.