阅读说明：本技术 粉体供给料斗加压装置、气化炉设备及气化复合发电设备以及粉体供给料斗加压装置的控制方法 (Powder supply hopper pressurizing device, gasification furnace facility, gasification combined power generation facility, and method for controlling powder supply hopper pressurizing device ) 是由 浦方悠一郎 葛西润 西村幸治 于 2019-02-15 设计创作，主要内容包括：具备：第一缓冲罐(87),以预定的压力蓄积对粉体供给料斗(80)供给的加压气体；第二缓冲罐(88)；下部压力调整氮气系统(83),连接于粉体供给料斗(80),在向燃烧器供给粉体燃料时朝向积存于粉体供给料斗(80)内的粉体燃料供给气体；及控制部(90),以利用第一缓冲罐(87)将粉体供给料斗(80)加压至第一压力后利用第二缓冲罐(88)将粉体供给料斗(80)加压至第二压力的方式进行控制,控制部(90)在判断为第一缓冲罐(87)和第二缓冲罐(88)的任一者不可使用的情况下,使用能够运用的第一缓冲罐(87)或第二缓冲罐(88)和气体供给系统(83)来将粉体供给料斗(80)加压。(The disclosed device is provided with: a first buffer tank (87) for accumulating pressurized gas supplied to the powder supply hopper (80) at a predetermined pressure; a second buffer tank (88); a lower pressure-adjusting nitrogen system (83) connected to the powder supply hopper (80) and configured to supply gas to the pulverized fuel stored in the powder supply hopper (80) when the pulverized fuel is supplied to the burner; and a control unit (90) that controls the powder supply hopper (80) to be pressurized to a first pressure by the first buffer tank (87) and then to be pressurized to a second pressure by the second buffer tank (88), wherein the control unit (90) uses the first buffer tank (87) or the second buffer tank (88) that can be operated and the gas supply system (83) to pressurize the powder supply hopper (80) when determining that either the first buffer tank (87) or the second buffer tank (88) is unusable.)

1. A powder supply hopper pressurizing device is provided with:

a first buffer tank for accumulating pressurized gas at a predetermined pressure, the pressurized gas being supplied to a powder supply hopper for supplying pressurized pulverized fuel;

a second buffer tank which is provided in parallel with the first buffer tank and accumulates the pressurized gas supplied to the powder supply hopper at a predetermined pressure;

a gas supply system connected to the powder supply hopper, for supplying pressurized gas to the pulverized fuel stored in the powder supply hopper when supplying the pressurized pulverized fuel; and

a control unit configured to control the powder supply hopper to be pressurized to a first pressure by the first buffer tank and to be pressurized to a second pressure by the second buffer tank,

the control unit, when determining that any one of the first buffer tank and the second buffer tank is unusable, pressurizes the powder supply hopper using the first buffer tank or the second buffer tank, which is usable, and the gas supply system.

2. The powder supply hopper pressurizing apparatus according to claim 1, wherein,

the powder supply hopper pressurizing device is provided with:

a pressurized gas production device that supplies pressurized gas to the first buffer tank, the second buffer tank, and the gas supply system;

a first buffer tank inlet valve provided on the pressurized gas production apparatus side of the first buffer tank;

a first buffer tank outlet valve provided on the powder supply hopper side of the first buffer tank;

a second buffer tank inlet valve provided on the pressurized gas production apparatus side of the second buffer tank; and

a second buffer tank outlet valve provided on the powder supply hopper side of the second buffer tank,

the controller may determine that the first buffer tank is unusable when an abnormality occurs in the first buffer tank inlet valve or the first buffer tank outlet valve, and may determine that the second buffer tank is unusable when an abnormality occurs in the second buffer tank inlet valve or the second buffer tank outlet valve.

3. The powder supply hopper pressurizing apparatus according to claim 2, wherein,

the powder supply hopper pressurizing device includes a buffer tank pressure regulating valve provided between the pressurized gas producing device and the first and second buffer tank inlet valves to regulate the pressure supplied to the first and second buffer tanks,

the control unit closes the buffer tank pressure adjustment valve at least when the powder supply hopper is pressurized by the gas supply system.

4. The powder supply hopper pressurizing device according to any one of claims 1 to 3, wherein,

the powder supply hopper pressurizing device is provided with:

a plurality of pressurizing nozzles for supplying a pressurizing gas to the powder supply hopper;

a plurality of filters provided at the tip of the pressurizing nozzle, facing the space in the powder supply hopper where the pulverized fuel is stored, and allowing the pressurized gas to pass therethrough;

a powder supply hopper pressure sensor for detecting the pressure in the powder supply hopper; and

a pressurized gas pressure sensor that detects a pressure of the pressurized gas branched at a branch point and supplied to the pressurizing nozzle on an upstream side of the branch point,

the control unit determines that the filter is broken when a differential pressure between the pressure detected by the powder supply hopper pressure sensor and the pressure detected by the pressurized gas pressure sensor is equal to or less than a predetermined value.

5. A gasification furnace facility is provided with:

the powder supply hopper pressurizing device according to any one of claims 1 to 4; and

and a gasification furnace to which the pulverized fuel is supplied from the powder supply hopper pressurizing device.

6. A gasification combined cycle power plant is provided with:

the gasifier apparatus of claim 5;

a gas turbine that is rotationally driven by burning at least a part of the generated gas generated in the gasification furnace facility;

a steam turbine that is rotationally driven by steam generated in an exhaust heat recovery boiler into which turbine exhaust gas discharged from the gas turbine is introduced; and

an electrical generator rotationally coupled to the gas turbine and/or the steam turbine.

7. A method for controlling a powder supply hopper pressurization device, the powder supply hopper pressurization device comprising:

a first buffer tank for accumulating pressurized gas at a predetermined pressure, the pressurized gas being supplied to a powder supply hopper for supplying pressurized pulverized fuel;

a second buffer tank which is provided in parallel with the first buffer tank and accumulates the pressurized gas supplied to the powder supply hopper at a predetermined pressure; and

a gas supply system connected to the powder supply hopper for supplying pressurized gas to the pulverized fuel stored in the powder supply hopper when supplying the pressurized pulverized fuel,

wherein the control method of the powder supply hopper pressurizing device comprises the following steps: the powder supply hopper is pressurized to a first pressure by the first buffer tank and then pressurized to a second pressure by the second buffer tank,

when it is determined that any one of the first buffer tank and the second buffer tank is unusable, the powder supply hopper is pressurized using the first buffer tank or the second buffer tank that can be operated and the gas supply system.

Technical Field

The present invention relates to a powder supply hopper pressurizing device for pressurizing a powder supply hopper, a gasification furnace facility and a gasification combined cycle power generation facility, and a method for controlling the powder supply hopper pressurizing device.

Background

Conventionally, as a gasification furnace facility, a carbon-containing fuel gasification facility (coal gasification facility) is known, which generates a combustible gas by supplying a carbon-containing solid fuel such as coal into a gasification furnace and partially combusting and gasifying the carbon-containing solid fuel.

A pressurizing device for pressurizing a pulverized coal supply hopper for supplying pulverized coal and raw coal using coal as a raw material is known as a gasification furnace facility (patent document 1). In this document, two buffer tanks for temporarily storing nitrogen gas for pressurization are provided in parallel. One surge tank is used to pressurize the pulverized coal feed hopper to a predetermined pressure, and then the other surge tank is used to pressurize the pulverized coal feed hopper to a target pressure.

Disclosure of Invention

Problems to be solved by the invention

However, the pressurizing device described in the above-mentioned document is established when both the buffer tanks can perform normal operations. If any of the buffer tanks is considered to be abnormal and unusable, it takes a lot of time to pressurize the pulverized coal feed hopper to the target pressure by repeating the supply from the buffer tank and the pressurization to the buffer tank for the nitrogen gas for pressurization. Therefore, in such a case, there is a problem that the operation pressure of the gasification furnace has to be lowered to operate at a low load.

Further, a filter made of sintered metal or the like having strength higher than that of the metal mesh may be provided at the tip of the pressurizing nozzle for supplying the pressurized gas to the pulverized coal supply hopper so as to face the pulverized coal accumulated in the pulverized coal supply hopper. In the case where the filter of the pressurizing nozzle provided in the pulverized coal feeding hopper is broken due to the flow rate of the pressurizing gas or the like, there is a fear that the pulverized coal enters the pressurizing nozzle to cause another trouble, but since a plurality of filters are used, even if one or some of the filters are broken, the breakage of the filter is not easily detected, and a means for detecting the breakage is not provided. Therefore, if the operator does not constantly monitor the flow state of the pulverized coal in the pulverized coal feed hopper with attention, the breakage of the filter cannot be confirmed until the pulverized coal feed hopper is opened for inspection. Therefore, the timing of setting up the replacement component after checking for damage in an inspection or the like is delayed, and recovery may take time.

The powder supply hopper pressurizing device, the gasification furnace facility, the gasification combined power generation facility, and the method for controlling the powder supply hopper pressurizing device according to the present disclosure have been made in view of such circumstances, and an object thereof is to be able to pressurize a powder supply hopper to a target pressure even when one of two buffer tanks becomes unusable.

In addition, the object is to detect the breakage of the filter attached to the tip of the pressurizing nozzle during operation.

Means for solving the problems

A powder supply hopper pressurizing device according to an aspect of the present invention includes: a first buffer tank for accumulating pressurized gas at a predetermined pressure, the pressurized gas being supplied to a powder supply hopper for supplying pressurized pulverized fuel; a second buffer tank which is provided in parallel with the first buffer tank and accumulates the pressurized gas supplied to the powder supply hopper at a predetermined pressure; a gas supply system connected to the powder supply hopper, for supplying pressurized gas to the pulverized fuel accumulated in the powder supply hopper when supplying the pressurized pulverized fuel; and a control unit configured to control the powder supply hopper to be pressurized to a first pressure by the first buffer tank and then to be pressurized to a second pressure by the second buffer tank, wherein the control unit is configured to pressurize the powder supply hopper by using the first buffer tank or the second buffer tank and the gas supply system, which are operable, when it is determined that either one of the first buffer tank and the second buffer tank is unusable.

The powder supply hopper is pressurized to a target pressure after the powder fuel is supplied to the inside at atmospheric pressure. In the pressurization, the pressurized gas in the first buffer tank is pressurized to a first pressure and then the pressurized gas in the second buffer tank is pressurized to a second pressure (for example, a target pressure). Therefore, when one of the buffer tanks is abnormal and the first buffer tank or the second buffer tank becomes unusable, the powder supply hopper cannot be pressurized to the target pressure, and the supply from the buffer tank and the pressurization to the buffer tank are repeatedly performed to the pressurization gas, and the like, and it takes time until the target pressure is reached. Therefore, when one buffer tank becomes unusable, the powder supply hopper is pressurized using a gas supply system that supplies pressurized gas to the pulverized fuel accumulated in the powder supply hopper when the pulverized fuel is supplied. That is, during normal operation, the gas supply system used for supplying the pulverized fuel after the powder supply hopper is pressurized and for additionally supplying the gas for transportation for fluidizing the pulverized fuel accumulated in the vicinity of the wall surface of the powder supply hopper is also used as the pressurized gas supply system for pressurizing the powder supply hopper. Thus, even when the first buffer tank or the second buffer tank becomes unusable, the powder supply hopper can be pressurized to the target pressure.

Further, a powder supply hopper pressing device according to an aspect of the present invention includes: a pressurized gas production device configured to supply a pressurized gas to the first buffer tank, the second buffer tank, and the gas supply system; a first buffer tank inlet valve provided on the pressurized gas production apparatus side of the first buffer tank; a first buffer tank outlet valve provided on the powder supply hopper side of the first buffer tank; a second buffer tank inlet valve provided on the pressurized gas production apparatus side of the second buffer tank; and a second buffer tank outlet valve provided on the powder supply hopper side of the second buffer tank, wherein the control unit determines that the first buffer tank is unusable when an abnormality occurs in the first buffer tank inlet valve or the first buffer tank outlet valve, and determines that the second buffer tank is unusable when an abnormality occurs in the second buffer tank inlet valve or the second buffer tank outlet valve.

When an abnormality occurs in an inlet valve or an outlet valve of a buffer tank, the control unit determines that the buffer tank connected to the inlet valve or the outlet valve is unusable. Thus, since it is possible to determine which buffer tank is unusable by the control unit, it is not necessary for the operator to determine the adjustment of the operation load of the powder supply hopper pressurizing device or the gasification furnace to which the pulverized fuel is supplied.

In the powder supply hopper pressurizing apparatus according to the aspect of the present invention, the control unit may control the pressure of the pressurized gas to be supplied to the first buffer tank and the second buffer tank, and may control the pressure of the pressurized gas to be supplied to the first buffer tank and the second buffer tank, based on the pressure of the pressurized gas, and the pressure of the pressurized gas to be supplied to the first buffer tank and the second buffer tank.

While the powder supply hopper is pressurized by the gas supply system, the pressurized gas produced by the pressurized gas production device is consumed. At this time, at least the buffer tank pressure adjustment valve is closed, and the pressurized gas is not guided to the first buffer tank and the second buffer tank. Accordingly, since the supply amount of the pressurized gas produced by the pressurized gas production device is limited to the upper limit, the pressurized gas produced by the pressurized gas production device can be supplied mainly to the gas supply system, and the shortage of the supply of the pressurized gas due to the decrease in the source pressure at the pressurized gas outlet of the pressurized gas production device can be avoided.

Further, a powder supply hopper pressing device according to an aspect of the present invention includes: a plurality of pressurizing nozzles for supplying a pressurizing gas to the powder supply hopper; a plurality of filters provided at the tip of the pressurizing nozzle, facing the space in the powder supply hopper where the pulverized fuel is stored, and allowing the pressurized gas to pass therethrough; a powder supply hopper pressure sensor for detecting the pressure in the powder supply hopper; and a pressurized gas pressure sensor that detects a pressure of the pressurized gas branched at the branching point and supplied to the pressurizing nozzle on an upstream side of the branching point, wherein the control unit determines that the filter is broken when a differential pressure between a pressure detected by the powder supply hopper pressure sensor and a pressure detected by the pressurized gas pressure sensor is equal to or less than a predetermined value.

Filters made of porous sintered metal provided at the tips of a plurality of pressurizing nozzles provided in a powder supply hopper may be damaged by abrasion, cracking due to a sudden change in gas flow velocity, or the like. The pressure loss in the filter is small, and if the filter is broken by abrasion, breakage, or the like, the pressure loss in the filter is small, but since there are a plurality of filters, it is not easy to detect the occurrence of breakage when one or some of the filters are broken.

As a result of the observation by the inventors, attention has been paid to the differential pressure between the pressure of the pressurized gas in the header pipe upstream of the branch point for supplying the pressurized gas and the pressure in the powder supply hopper. It was confirmed that: when one or some of the filters among the plurality of filters are broken, there is a change in the differential pressure.

When the differential pressure between the pressure in the powder supply hopper and the pressure of the pressurized gas is equal to or less than a predetermined value, it is determined that the filter is broken. Thus, the operator can prepare the replacement component at an appropriate timing without visually checking the filter.

A gasification furnace facility according to an aspect of the present invention includes the powder supply hopper pressurizing device described in any one of the above and a gasification furnace to which the pulverized fuel is supplied from the powder supply hopper pressurizing device.

Further, a gasification combined cycle plant according to an aspect of the present invention includes: the above-described gasification furnace apparatus; a gas turbine that is rotationally driven by burning at least a part of the generated gas generated in the gasification furnace facility; a steam turbine that is rotationally driven by steam generated in an exhaust heat recovery boiler into which turbine exhaust gas discharged from the gas turbine is introduced; and a generator rotationally coupled to the gas turbine and/or the steam turbine.

In a method for controlling a powder supply hopper pressurizing device according to an aspect of the present invention, the powder supply hopper pressurizing device includes: a first buffer tank for accumulating pressurized gas at a predetermined pressure, the pressurized gas being supplied to a powder supply hopper for supplying pressurized pulverized fuel; a second buffer tank which is provided in parallel with the first buffer tank and accumulates the pressurized gas supplied to the powder supply hopper at a predetermined pressure; and a gas supply system connected to the powder supply hopper, for supplying a pressurized gas to the powder fuel stored in the powder supply hopper when supplying the pressurized powder fuel, wherein the first buffer tank is used to pressurize the powder supply hopper to a first pressure, and the second buffer tank is used to pressurize the powder supply hopper to a second pressure, and when one of the first buffer tank and the second buffer tank is determined to be unusable, the first buffer tank or the second buffer tank and the gas supply system which can be used are used to pressurize the powder supply hopper.

Effects of the invention

Since the powder supply hopper is pressurized using the gas supply system, the powder supply hopper can be pressurized to the target pressure even if one of the two buffer tanks becomes unusable.

Drawings

Fig. 1 is a schematic configuration diagram showing an integrated coal gasification combined cycle plant according to a first embodiment of the present invention.

Fig. 2 is a schematic configuration diagram showing the gasification furnace facility of fig. 1.

Fig. 3 is a schematic configuration diagram showing a pressurizing device for pressurizing a pulverized coal feed hopper.

Fig. 4 is a schematic configuration diagram showing a pressurizing nozzle attached to a pulverized coal feeding hopper.

Fig. 5 is a timing chart showing the pressurization process in the case where the second buffer tank becomes unusable.

Fig. 6 is a timing chart showing the pressurization process in the case where the first buffer tank becomes unusable.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[ first embodiment ]

Fig. 1 shows a schematic configuration of an integrated coal gasification combined cycle plant 10 to which a gasification furnace facility 14 is applied.

An Integrated Gasification Combined Cycle (IGCC) 10 employs an air combustion system that uses air as a main oxidant and produces a combustible gas (generated gas) from a fuel in a Gasification furnace facility 14. The integrated coal gasification combined cycle plant 10 purifies the generated gas generated in the gasification furnace plant 14 in the gas purification plant 16 to form a fuel gas, and then supplies the fuel gas to the gas turbine 17 to generate power. That is, the integrated coal gasification combined cycle plant 10 is an air-fired (air-blown) power plant. As the fuel to be supplied to the gasification furnace facility 14, for example, a carbonaceous solid fuel such as coal is used.

As shown in fig. 1, an integrated coal gasification combined cycle plant (integrated gasification combined cycle plant) 10 includes: a coal supply facility 11, a gasification furnace facility 14, a char Recovery facility 15, a gas purification facility 16, a gas turbine 17, a Steam turbine 18, a Generator 19, and an exhaust Heat Recovery boiler (HRSG) 20.

The coal supply facility 11 is supplied with coal as a carbon-containing solid fuel as raw coal, and pulverizes the coal by a coal mill (not shown) or the like to produce fine granular pulverized coal (pulverized fuel). The pulverized coal produced by the coal supply facility 11 is pressurized at the outlet of the coal supply line 11a by nitrogen gas as a transport inert gas supplied from an air separation facility 42 described later, and is supplied to the gasification furnace facility 14. The inert gas is an inert gas having an oxygen content of about 5 vol% or less, and nitrogen, carbon dioxide gas, argon, and the like are typical examples, but the inert gas is not necessarily limited to about 5 vol% or less.

The coal supply facility 11 includes a pulverized coal supply hopper pressure device (powder supply hopper pressure device) 1 according to the present embodiment. The details will be described later.

The pulverized coal produced by the coal supply facility 11 is supplied to the gasification furnace facility 14, and the char (unreacted portion of coal and ash: pulverized fuel) recovered by the char recovery facility 15 is returned to the gasification furnace facility 14 and supplied to the gasification furnace facility 14 for reuse.

A compressed air supply line 41 from the gas turbine 17 (compressor 61) is connected to the gasification furnace facility 14, and a part of the compressed air compressed by the gas turbine 17 can be boosted to a predetermined pressure by the booster 68 and supplied to the gasification furnace facility 14. The air separation unit 42 separates air in the atmosphere to generate nitrogen and oxygen, and the air separation unit 42 and the gasification furnace unit 14 are connected by a first nitrogen supply line 43. A coal supply line 11a from the coal supply facility 11 is connected to the first nitrogen supply line 43. A second nitrogen supply line 45 branched from the first nitrogen supply line 43 is also connected to the gasification furnace facility 14, and a char return line 46 from the char recovery facility 15 is connected to the second nitrogen supply line 45. The air separation plant 42 is connected to the compressed air supply line 41 via an oxygen supply line 47. The nitrogen gas separated by the air separation facility 42 is used as a gas for transporting coal or char by flowing through the first nitrogen gas supply line 43 and the second nitrogen gas supply line 45. The oxygen gas separated by the air separation facility 42 is used as an oxidizing agent in the gasification furnace facility 14 by flowing through the oxygen gas supply line 47 and the compressed air supply line 41.

The gasification furnace facility 14 includes, for example, a two-stage entrained-flow type gasification furnace 101 (see fig. 2). The gasification furnace facility 14 forms a generated gas by partially combusting and gasifying coal (pulverized coal) and char supplied therein with an oxidizing agent (air, oxygen). In addition, the gasification furnace equipment 14 is provided with a foreign matter removal equipment 48 that removes foreign matter (slag) mixed into the pulverized coal. A gas generation line 49 for supplying the generated gas to the char recovery facility 15 is connected to the gasification furnace facility 14, and the generated gas including char can be discharged. In this case, as shown in fig. 2, the generated gas may be cooled to a predetermined temperature by providing a syngas cooler 102 (gas cooler) in the gas generation line 49, and then supplied to the char recovery facility 15.

The char recovery facility 15 includes a dust collecting facility 51 and a supply hopper 52. In this case, the dust collecting device 51 is composed of one or more cyclones or porous filters, and can separate char contained in the generated gas generated by the gasification furnace facility 14. The generated gas from which char has been separated is sent to the gas purification facility 16 through the gas discharge line 53. The supply hopper 52 accumulates the char separated from the generated gas by the dust collecting device 51. Further, a magazine may be disposed between the dust collecting device 51 and the supply hopper 52, and a plurality of supply hoppers 52 may be connected to the magazine. A char return line 46 from the feed hopper 52 is connected to the second nitrogen supply line 45.

The gas purification device 16 performs gas purification by removing impurities such as sulfur compounds and nitrogen compounds from the produced gas from which the char is separated by the char recovery device 15. The gas purification facility 16 purifies the generated gas to produce fuel gas, and combusts the fuel gasAnd a turbine 17. In addition, the generated gas after the separation of the char contains sulfur (H)₂S, etc.), sulfur components are removed and recovered by an amine absorbent or the like in the gas purification apparatus 16 and effectively utilized.

The gas turbine 17 includes: the compressor 61, the combustor 62, and the turbine 63 are coupled to each other by a rotary shaft 64. A compressed air supply line 65 from the compressor 61, a fuel gas supply line 66 from the gas purification facility 16, and a combustion gas supply line 67 extending to the turbine 63 are connected to the combustor 62. The gas turbine 17 is provided with a compressed air supply line 41 extending from the compressor 61 to the gasification furnace facility 14, and a booster 68 is provided in the middle thereof. Therefore, in the combustor 62, a part of the compressed air supplied from the compressor 61 and at least a part of the fuel gas supplied from the gas purification apparatus 16 are mixed and burned to generate a combustion gas, and the generated combustion gas is supplied to the turbine 63. The turbine 63 rotates the generator 19 by driving the rotary shaft 64 with the supplied combustion gas.

The steam turbine 18 includes a turbine 69 coupled to the rotating shaft 64 of the gas turbine 17, and the generator 19 is coupled to a base end portion of the rotating shaft 64. An exhaust line 70 from the gas turbine 17 (turbine 63) is connected to the exhaust heat recovery boiler 20, and steam is generated by heat exchange between the water supply to the exhaust heat recovery boiler 20 and the exhaust gas of the turbine 63. Further, a steam supply line 71 and a steam recovery line 72 are provided between the exhaust heat recovery boiler 20 and the turbine 69 of the steam turbine 18, and a condenser 73 is provided in the steam recovery line 72. The steam generated by the exhaust heat recovery boiler 20 may include steam generated by heat exchange with the generated gas in the syngas cooler 102 of the gasification furnace 101. Therefore, in the steam turbine 18, the turbine 69 is driven to rotate by the steam supplied from the exhaust heat recovery boiler 20, and the generator 19 is driven to rotate by rotating the rotary shaft 64.

A gas cleaning device 74 is provided between the outlet of the exhaust heat recovery boiler 20 and the flue pipe 75.

Next, the operation of the integrated coal gasification combined cycle plant 10 will be described.

In the integrated coal gasification combined cycle plant 10, when raw coal (coal) is supplied to the coal supply equipment 11, the coal is pulverized into fine particles in the coal supply equipment 11 to become pulverized coal. The pulverized coal produced by the coal supply facility 11 is supplied to the gasification furnace facility 14 while flowing through the first nitrogen supply line 43 by the nitrogen gas supplied from the air separation facility 42. The char recovered by the char recovery facility 15 described later is supplied to the gasification furnace facility 14 through the second nitrogen supply line 45 by the nitrogen supplied from the air separation facility 42. The compressed air extracted from the gas turbine 17 described later is boosted by the booster 68, and then supplied to the gasification furnace facility 14 through the compressed air supply line 41 together with the oxygen supplied from the air separation facility 42.

In the gasification furnace facility 14, the supplied pulverized coal and char are combusted by compressed air (oxygen), and the pulverized coal and char are gasified to generate a generated gas. The generated gas is discharged from the gasification furnace facility 14 through a gas generation line 49 and is sent to the char recovery facility 15.

In the char recovery facility 15, the generated gas is first supplied to the dust collecting facility 51, whereby fine particles contained in the generated gas are separated from char. The generated gas from which char has been separated is sent to the gas purification facility 16 through the gas discharge line 53. On the other hand, the fine char separated from the produced gas is accumulated in the supply hopper 52, and is returned to the gasification furnace facility 14 through the char return line 46 to be reused.

The produced gas from which the char is separated by the char recovery facility 15 is subjected to gas purification by removing impurities such as sulfur compounds and nitrogen compounds in the gas purification facility 16, thereby producing a fuel gas. The compressor 61 generates compressed air and supplies the compressed air to the combustor 62. The combustor 62 mixes the compressed air supplied from the compressor 61 with the fuel gas supplied from the gas purification apparatus 16, and generates combustion gas by combustion. The combustion gas rotationally drives the turbine 63, thereby rotationally driving the compressor 61 and the generator 19 via the rotary shaft 64. In this way, the gas turbine 17 can generate electric power.

The exhaust-heat-recovery boiler 20 generates steam by exchanging heat between the exhaust gas discharged from the turbine 63 in the gas turbine 17 and the water supply to the exhaust-heat-recovery boiler 20, and supplies the generated steam to the steam turbine 18. In the steam turbine 18, the turbine 69 is rotationally driven by the steam supplied from the exhaust heat recovery boiler 20, whereby the generator 19 can be rotationally driven via the rotary shaft 64 to generate electric power.

Instead of forming the same shaft to rotate the single generator 19, the gas turbine 17 and the steam turbine 18 may be formed to rotate a plurality of generators by forming different shafts.

Then, the gas cleaning facility 74 removes harmful substances in the exhaust gas discharged from the exhaust heat recovery boiler 20, and the cleaned exhaust gas is discharged to the atmosphere from the flue pipe 75.

Next, the gasification furnace facility 14 in the integrated coal gasification combined cycle plant 10 will be described in detail with reference to fig. 1 and 2.

As shown in fig. 2, the gasification furnace facility 14 includes a gasification furnace 101 and a syngas cooler 102.

The gasification furnace 101 is formed to extend in the vertical direction, pulverized coal and oxygen gas are supplied to the lower side in the vertical direction, and a generated gas that is partially combusted and gasified flows from the lower side to the upper side in the vertical direction. The gasification furnace 101 includes a pressure vessel 110 and a gasification furnace wall 111 provided inside the pressure vessel 110. The gasification furnace 101 has an annular portion 115 formed in a space between the pressure vessel 110 and the gasification furnace wall 111. The gasification furnace 101 has a burner portion 116, a diffuser portion 117, and a decompressor portion 118 formed in this order from the lower side in the vertical direction (i.e., the upstream side in the flow direction of the generated gas) in the space inside the gasification furnace wall 111.

The pressure vessel 110 is formed in a cylindrical shape having a hollow space therein, and has a gas discharge port 121 formed at an upper end portion thereof and a slag hopper 122 formed at a lower end portion (bottom portion) thereof. The gasifier wall 111 is formed in a cylindrical shape having a hollow space therein, and is provided so that a wall surface thereof faces an inner surface of the pressure vessel 110. In the present embodiment, the pressure vessel 110 is cylindrical, and the diffuser portion 117 of the gasifier wall 111 is also formed in a cylindrical shape. The gasifier wall 111 is connected to the inner surface of the pressure vessel 110 by a support member, not shown.

The gasifier wall 111 separates the interior of the pressure vessel 110 into an interior space 154 and an exterior space 156. The gasifier wall 111 has a cross-sectional shape that changes at a diffuser portion 117 between the burner portion 116 and the pressure reducer portion 118. The gasifier wall 111 is provided such that its upper end on the vertically upper side is connected to the gas discharge port 121 of the pressure vessel 110 and its lower end on the vertically lower side is spaced from the bottom of the pressure vessel 110. The accumulated water is accumulated in the slag hopper 122 formed at the bottom of the pressure vessel 110, and the accumulated water is entered through the lower end portion of the gasifier wall 111 to seal the inside and outside of the gasifier wall 111. Burners 126 and 127 are inserted into gasifier wall 111, and syngas cooler 102 is disposed in inner space 154. The structure of the gasifier wall 111 will be described later.

The annular portion 115 is a space formed inside the pressure vessel 110 and outside the gasifier wall 111, that is, an outer space 156, and nitrogen gas, which is an inert gas separated by the air separation device 42, is supplied to the annular portion 115 through a nitrogen gas supply line, not shown. Therefore, the annular portion 115 becomes a space filled with nitrogen gas. Further, an unillustrated furnace pressure equalizing tube for equalizing the pressure in the gasification furnace 101 is provided in the vicinity of an upper portion of the annular portion 115 in the vertical direction. The furnace pressure equalizer is provided so as to communicate the inside and outside of the gasifier wall 111, and is configured to substantially equalize the pressure between the inside (the burner portion 116, the diffuser portion 117, and the pressure reducer portion 118) and the outside (the annular portion 115) of the gasifier wall 111 so that the pressure difference is within a predetermined pressure.

The burner unit 116 is a space for partially burning the pulverized coal, the char, and the air, and a combustion device including a plurality of burners 126 is disposed on the gasifier wall 111 of the burner unit 116. The high-temperature combustion gas obtained by burning part of the pulverized coal and the char in the burner portion 116 flows into the decompressor portion 118 through the diffuser portion 117.

The decompressor 118 becomes a space: the gasification furnace is provided with a space for supplying pulverized coal to the combustion gas from the burner part 116 and partially combusting the pulverized coal while maintaining a high temperature state necessary for the gasification reaction, and decomposing and gasifying the pulverized coal into volatile components (carbon monoxide, hydrogen, lower hydrocarbons, etc.) to generate a generated gas, and a combustion device comprising a plurality of burners 127 is disposed on the gasifier wall 111 of the decompressor part 118.

Syngas cooler 102 is provided inside gasifier wall 111 and on the upper side of pressure reducer portion 118 in the vertical direction of combustor 127. The syngas cooler 102 is a heat exchanger, and an evaporator (evaporation device) 131, a superheater (superheating device) 132, and an economizer (economizer device) 134 are arranged in this order from the lower side of the gasifier wall 111 in the vertical direction (the upstream side in the flow direction of the generated gas). These syngas coolers 102 cool the generated gas by heat exchange with the generated gas generated in pressure reducer portion 118. The number of evaporators (evaporation devices) 131, superheaters (superheating devices) 132, and economizers (economizer devices) 134 is not limited to the number shown in the figure.

The gasification furnace facility 14 operates as follows.

In the gasification furnace 101 of the gasification furnace facility 14, nitrogen gas and pulverized coal are injected and ignited by the burner 127 of the decompressor 118, and pulverized coal, char and compressed air (oxygen gas) are injected and ignited by the burner 126 of the burner 116. Then, the burner section 116 generates high-temperature combustion gas by burning the pulverized coal and the char. In the burner section 116, molten slag is generated in the high-temperature gas by the combustion of the pulverized coal and the char, and this molten slag adheres to the gasifier wall 111, falls to the furnace bottom, and is finally discharged to the accumulated water in the slag hopper 122. The high-temperature combustion gas generated in the combustor portion 116 passes through the diffuser portion 117 and rises toward the decompressor portion 118. In the pressure reducer portion 118, the pulverized coal is mixed with a high-temperature combustion gas while maintaining a high-temperature state necessary for the gasification reaction, and the pulverized coal is partially combusted in a high-temperature reducing atmosphere to perform the gasification reaction, thereby generating a generated gas. The vaporized generated gas flows from the lower side to the upper side in the vertical direction.

[ pressurizing device for pulverized coal-feeding hopper ]

Fig. 3 shows a schematic configuration of a pulverized coal supply hopper pressure device (powder supply hopper pressure device) 1 provided in the coal supply facility 11 shown in fig. 1. The pulverized coal feed hopper pressurizing device 1 pressurizes a pulverized coal feed hopper 80 (hereinafter, referred to as "hopper 80") to a target pressure. The target pressure is a pressure necessary for supplying the pulverized coal to the burners 126 and 127 of the gasification furnace 101, and in the present embodiment, is set to a predetermined pressure or higher than the pressure in the pressure vessel 110 (see fig. 2) when the gasification furnace 101 is in use.

A plurality of hoppers 80 (for example, three hoppers in the present embodiment) are provided, and are arranged in parallel with the pulverized coal supply destination of the gasification furnace facility 14. Each hopper 80 is supplied with pulverized coal at atmospheric pressure, and is sequentially switched one by one so as to discharge the pressurized pulverized coal when in use. Therefore, when one of the hoppers 80 is discharging the pulverized coal, the other hopper 80 is in a standby state for the discharge and is configured by a hopper to which the pulverized coal is supplied under atmospheric pressure and which is pressurized to a predetermined pressure so as to be able to supply the pulverized coal.

The hopper 80 is provided with a hopper pressure sensor (powder supply hopper pressure sensor) P1 for detecting the pressure in the hopper 80. The detection output of the hopper pressure sensor P1 is sent to the control unit 90.

As the pressurizing gas for pressurizing the hopper 80, nitrogen gas is used in the present embodiment. An upper stage pressurized nitrogen gas system 81, a lower stage pressurized nitrogen gas system 82, a lower pressure-regulated nitrogen gas system (gas supply system) 83, and a fluidized nitrogen gas system 84 are connected to the hopper 80.

The upper-stage pressurized nitrogen system 81 is provided with an upper pressurized nitrogen shut-off valve VI-1. The lower stage pressurized nitrogen system 82 is provided with a lower pressurized nitrogen shut-off valve VI-2. The upper stage pressurized nitrogen gas system 81 and the lower stage pressurized nitrogen gas system 82 are each connected to a pressurized nitrogen gas bypass system 85 via an orifice 85a for restricting a sudden increase in the flow rate of a fluidizing gas such as nitrogen gas when the shut valve is opened. The pressurized nitrogen bypass system 85 is provided with a pressurized nitrogen bypass shutoff valve XI.

The lower pressure-regulated nitrogen gas system 83 is for fluidizing pulverized coal deposited in the vicinity of the wall surface of the hopper 80 while applying a pressure for conveying the pulverized coal to an outlet at the bottom of the hopper 80 into the hopper 80. Therefore, the lower pressure-regulated nitrogen gas system 83 is used when the pulverized coal is supplied from the hopper 80 to the gasification furnace 101. In the present embodiment, as will be described later, the lower pressure-regulated nitrogen gas system 83 is also used when the pressure in the hopper 80 is increased from the atmospheric pressure to the operating pressure. The lower pressure-adjusting nitrogen system 83 is provided with a lower pressure-adjusting nitrogen shutoff valve IX and a lower pressure-adjusting nitrogen flow rate adjustment valve X. Since the upstream side of the lower pressure-adjusted nitrogen gas system 83 is connected to an ASU (Air Separation Unit: pressurized gas production Unit), a large flow rate of nitrogen gas can be supplied, but since there is an upper limit to the amount of nitrogen gas that can be supplied by the ASU, if nitrogen gas is continuously used from the lower pressure-adjusted nitrogen gas system 83 at all times, the nitrogen gas supply source pressure at the outlet of the ASU may decrease and the nitrogen gas supply amount may become insufficient. Therefore, when the nitrogen gas is supplied to the lower pressure adjustment nitrogen gas system 83, it is important to manage to reduce the nitrogen gas consumption in other apparatuses.

The fluidizing nitrogen system 84 fluidizes the pulverized coal accumulated around the pulverized coal outlet of the hopper 80. The fluidized nitrogen system 84 is provided with a fluidized nitrogen pressure regulating valve VII and a fluidized nitrogen shutoff valve VIII. The upstream side of the fluidized nitrogen system 84 is connected to the ASU.

Upstream sides of the upper stage pressurized nitrogen system 81, the lower stage pressurized nitrogen system 82, and the pressurized nitrogen bypass system 85 are connected to a common header 86. The header pipe 86 is provided with a header pipe pressure sensor (pressurized gas pressure sensor) P2 for detecting the pressure in the header pipe 86. The detection output of the header pressure sensor P2 is sent to the control unit 90.

A first buffer tank 87 and a second buffer tank 88 are provided upstream of the main pipe 86. The first buffer tank 87 and the second buffer tank 88 are provided in parallel with each other. That is, a first buffer tank side nitrogen gas system 87a connected to the first buffer tank 87 and a second buffer tank side nitrogen gas system 88a connected to the second buffer tank 88 are provided in parallel and connected to the common header pipe 86.

A first buffer tank inlet shutoff valve (first buffer tank inlet valve) I is provided on the upstream side of the first buffer tank 87. A first buffer tank outlet shut-off valve (first buffer tank outlet valve) II and a first buffer tank side orifice 87b for restricting the flow rate of nitrogen gas or the like so as not to increase suddenly when the pressurized gas is discharged by opening the first buffer tank outlet shut-off valve II are provided in this order from the upstream side on the downstream side of the first buffer tank 87.

A second surge tank inlet shutoff valve (second surge tank inlet valve) III is provided on the upstream side of the second surge tank 88. A second buffer tank outlet shutoff valve (second buffer tank outlet valve) IV and a second buffer tank side orifice 88b for restricting the flow rate of nitrogen gas or the like so as not to increase suddenly when the pressurized gas is discharged by opening the second buffer tank outlet shutoff valve IV are provided in this order from the upstream side on the downstream side of the second buffer tank 88. The diameter of the second buffer tank side orifice 88b is larger than the diameter of the first buffer tank side orifice 87 b. Thus, the pressurization by the second buffer tank 88 performed after the pressurization by the first buffer tank 87 is performed quickly.

A surge tank bypass system 89 is provided in parallel with the first surge tank 87 and the second surge tank 88. The downstream side of the surge tank bypass system 89 is connected to the main pipe 86. The surge tank bypass system 89 is provided with a surge tank bypass cut valve V and a bypass orifice 89b in this order from the upstream side. The diameter of the bypass-side orifice 89b is smaller than the diameter of the first buffer tank-side orifice 87 b.

Upstream sides of the first buffer tank side nitrogen system 87a, the second buffer tank side nitrogen system 88a, and the buffer tank bypass system 89 are connected to a common buffer tank pressurized nitrogen system 91. The upstream side of the surge tank pressurized nitrogen system 91 is connected to the ASU. The buffer tank pressurized nitrogen gas system 91 is provided with a buffer tank pressure adjustment valve 0 for adjusting the pressure supplied to the first buffer tank 87 and the second buffer tank 88.

The valves 0, I to XI are controlled by a control unit 90. The control unit 90 is configured by, for example, a CPU (Central processing unit), a RAM (Random Access Memory), a ROM (Read only Memory), a computer-readable storage medium, and the like. A series of processes for realizing various functions is stored in a storage medium or the like in the form of a program as an example, and the various functions are realized by the CPU reading the program into a RAM or the like and executing processing and arithmetic processing of information. The program may be installed in advance in a ROM or other storage medium, provided in a state of being stored in a computer-readable storage medium, or transmitted via a wired or wireless communication means. The storage medium that can be read by the computer is a magnetic disk, an optical magnetic disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like.

Fig. 4 shows a plurality of pressurizing nozzles 6 provided in the hopper 80. An upper stage pressurized nitrogen gas system 81, a lower stage pressurized nitrogen gas system 82, a lower pressure-regulated nitrogen gas system 83, and the like are connected to the upstream side of the pressurizing nozzle 6. A filter 6a made of, for example, a porous sintered metal having strength higher than that of a metal mesh is provided at the tip of the pressure nozzle 6. The filter 6a faces a space in the hopper 80 in which pulverized coal is stored, and allows pressurized gas such as nitrogen gas to permeate therethrough. The filter 6a prevents the pulverized coal in the hopper 80 from flowing back into and mixing into the nitrogen gas systems (81, 82, 83).

Next, a pressurizing method using the above-described pulverized coal-feeding hopper pressurizing apparatus 1 will be described. In the following description, the valves 0 and I to XI are denoted by reference numerals and their names are omitted. For example, the first surge tank inlet shutoff valve I is expressed only as "valve I".

[ case where both buffer tanks are normal ]

First, a case where the first buffer tank 87 and the second buffer tank 88 can be normally used (for example, a case where all of the valves I to IV are normally operated without showing an abnormality) will be described.

The pressure in the hopper 80 before pressurization is set to atmospheric pressure since pulverized coal is introduced into the hopper 80 from a pulverized coal bunker (not shown). Then, the hopper 80 is sealed and pressurized with a pressurized gas such as nitrogen gas.

The valve II is opened, and the first buffer tank 87 is used to pressurize the hopper 80 to a first pressure lower than the target pressure. When the first pressure is reached, valve II is closed. The first pressure is set to, for example, 60% or more and 90% or less of the target pressure.

Then, the valve IV is opened, and the hopper 80 is pressurized to a target pressure (second pressure) using the second buffer tank 88. At this time, since the diameter of the second buffer tank side orifice 88b is larger than the diameter of the first buffer tank side orifice 87b, the pressurization from the first pressure to the target pressure is rapidly performed.

When the first buffer tank 87 and the second buffer tank 88 can be used normally, the pressure in the hopper 80 of the lower pressure-regulated nitrogen system 83 is not increased. The lower pressure-regulated nitrogen system 83 fluidizes the pulverized coal accumulated in the first buffer tank 87 and the second buffer tank 88 when the pulverized coal is discharged.

[ case where the first buffer tank 87 is normal and the second buffer tank 88 indicates an abnormality and is not usable ]

A case where the first buffer tank 87 is normal and the second buffer tank 88 is failed and indicates an abnormality and becomes unusable, for example, a case where both the valves I and II are normal and at least one of the valves III and IV is failed and indicates an abnormality and does not operate will be described.

When at least one of the valves III and IV is detected to be malfunctioning and no longer operates, the control unit 90 determines that the second buffer tank 88 is unusable and switches to the present control. In this control, pressurization into the hopper 80 using the first buffer tank 87 and pressurization into the hopper 80 using the lower pressure adjustment nitrogen gas system 83 are performed in combination.

As shown in fig. 5, when the pressurization into the hopper 80 is started, the valve I is set from the open state to the closed state, and the valve XI is set from the closed state to the open state. In fig. 5, "C" means that the valve is in a closed state, and "O" means that the valve is in an open state. When the valve XI is opened, the pressurized nitrogen gas remaining in the main pipe 86 is supplied from the pressurized nitrogen gas bypass system 85 into the hopper 80 through the upper stage pressurized nitrogen gas system 81 and the lower stage pressurized nitrogen gas system 82, whereby the pressure in the main pipe 86 and the pressure in the hopper 80 are equalized, and the pressurized nitrogen gas remaining in the main pipe 86 is prevented from suddenly flowing into the hopper 80.

After the operation of the valves I and XI is completed, the valves VII and VIII are controlled from the closed state to the open state, and pressurized nitrogen gas is supplied into the hopper 80 by using the fluidized nitrogen gas system 84. Further, the valve IX is controlled from the open state to the closed state several seconds after the end of the operation of the valve XI. After the valve IX is opened, it is always opened to reduce the frequency of operation.

After the pressure equalization between the main pipe 86 and the hopper 80 is completed, the valve XI is controlled to be closed from the open state. Thereafter, the valves VI-1 and VI-2 are controlled from the closed state to the open state, and the preparation for pressurization using the upper stage pressurized nitrogen gas system 81 and the lower stage pressurized nitrogen gas system 82 is performed. The start operation at this time takes a predetermined time to perform the start operation using a speed controller (not shown). This prevents the occurrence of an excessive flow rate of sudden flushing into the filter 6a (see fig. 4) attached to the pressurizing nozzle 6, thereby preventing breakage.

When the actuation of the valves VI-1 and VI-2 is completed, the valve II is controlled from the closed state to the open state to start the pressurization based on the first buffer tank 87. At this time, the valve I is also controlled from the closed state to the open state, and nitrogen gas is supplied from the ASU. Therefore, the opening degree of the valve 0 gradually rises.

As indicated by a broken line (see fig. 5 and 6) with respect to the valve V, when the pressure in the hopper 80 is not increased to a predetermined initial pressure after equalizing the pressure between the main pipe 86 and the hopper 80, the valve V is controlled from the closed state to the open state, and the pressurization using the surge tank bypass system 89 is performed. When this pressurization is performed, the valves I and II are still closed as indicated by the broken lines.

When the pressure in the hopper 80 reaches the first pressure, the valves I and II are controlled from the open state to the closed state, and the valve X is controlled from the closed state to the open state. Thereby, pressurization of the hopper 80 using the lower pressure adjustment nitrogen system 83 is started.

The opening operation of the valve X takes a predetermined time by using a speed controller. This prevents the occurrence of an excessive flow rate of sudden flushing into the filter 6a (see fig. 4) attached to the pressurizing nozzle 6, thereby preventing breakage.

When the pressurization using the lower pressure adjustment nitrogen gas system 83 is performed, the valve 0 is fully closed. Thus, since the amount of nitrogen supplied from the ASU is limited to the upper limit, the nitrogen supply from the ASU to the first buffer tank 87 is stopped and limited to the lower pressure-regulating nitrogen system 83, thereby preventing the source pressure at the outlet of the ASU from dropping and the nitrogen supply from being insufficient.

When the pressure in the hopper 80 reaches the target pressure, the valves VI-1 and VI-2 are closed, and the opening degree of the valve X is decreased and maintained at a constant opening degree. Pressurization for transporting the pulverized coal using the lower pressure-regulated nitrogen system 83 is performed by maintaining the opening degree of the valve X at a constant value. Further, the opening degree of the valve VII is also decreased to a predetermined value and maintained at a constant opening degree. Thereby, the pulverized coal is fluidized by the fluidizing nitrogen system 84.

After the pressurization in the hopper 80 is completed, the first buffer tank 87 is pressurized by controlling the valve I from the closed state to the open state and opening the valve 0. When the pressure of the first buffer tank 87 is restored, the valve 0 is closed and the pressurization of the first buffer tank 87 is terminated.

[ case where the first buffer tank indicates a failure and is not usable and the second buffer tank is normal ]

A case where the first buffer tank 87 is not usable and the second buffer tank 88 is normal, for example, a case where at least one of the valves I and II is malfunctioning and indicates an abnormality without operating and the valves III and IV are normal will be described.

When detecting that at least one of the valves I and II has failed and indicates an abnormality and is no longer operating, the control unit 90 determines that the first buffer tank 87 is unusable and switches to the present control. In this control, the pressurization into the hopper 80 using the second buffer tank 88 and the pressurization into the hopper 80 using the lower pressure adjustment nitrogen gas system 83 are performed in combination.

As shown in fig. 6, when the pressurization into the hopper 80 is started, the valve III is controlled from the open state to the closed state, and the valve XI is controlled from the closed state to the open state. When the valve XI is opened, the pressurized nitrogen gas remaining in the mother pipe 86 is supplied from the pressurized nitrogen gas bypass system 85 into the hopper 80 through the upper stage pressurized nitrogen gas system 81 and the lower stage pressurized nitrogen gas system 82, and the pressure in the mother pipe 86 and the hopper 80 is equalized.

After the operation of the valves III and XI is completed, the valves VII and VIII are controlled from the closed state to the open state, and pressurized nitrogen gas is supplied into the hopper 80 by using the fluidized nitrogen gas system 84. Further, the valve IX is controlled from the open state to the closed state several seconds after the end of the operation of the valve XI. After the valve IX is opened, it is always opened to reduce the frequency of operation.

After the pressure equalization between the main pipe 86 and the hopper 80 is completed, the valve XI is controlled to be closed from the open state. Thereafter, the valves VI-1 and VI-2 are controlled from the closed state to the open state, and the preparation for pressurization using the upper stage pressurized nitrogen gas system 81 and the lower stage pressurized nitrogen gas system 82 is performed. The start operation at this time takes a predetermined time to perform the start operation using the speed controller. This prevents the occurrence of an excessive flow rate of sudden flushing into the filter 6a (see fig. 4) attached to the pressurizing nozzle 6, thereby preventing breakage.

As indicated by a broken line (see fig. 5 and 6) with respect to the valve V, when the pressure in the hopper 80 is not increased to a predetermined initial pressure after equalizing the pressure between the main pipe 86 and the hopper 80, the valve V is controlled from the closed state to the open state, and the pressurization using the surge tank bypass system 89 is performed.

After the actuation of valves VI-1 and VI-2 is complete, valve X is controlled from the closed state to the open state to begin pressurization of the nitrogen system 83 using the lower pressure regulation. The reason why the pressurization using the second buffer tank 88 is not performed at this timing is that since the diameter of the second buffer tank side orifice 88b is larger than the diameter of the first buffer tank side orifice 87b, when the initial pressurization is performed using the second buffer tank 88, the excessively flowing nitrogen gas that suddenly blows in flows and the filter 6a may be damaged. The actuation of the valve X takes a predetermined time to proceed using the speed controller. This prevents the occurrence of an excessive flow rate of sudden flushing into the filter 6a (see fig. 4) attached to the pressurizing nozzle 6, thereby preventing breakage.

When the pressure in the hopper 80 reaches a predetermined value by adjusting the pressurization in the nitrogen system 83 using the lower pressure, the valve X is controlled from the open state to the closed state, and the valves III and IV are controlled from the closed state to the open state, thereby switching to the pressurization by the second buffer tank 88. When the pressure in the hopper 80 reaches a predetermined value, the pressurization of the nitrogen gas system 83 is switched to the pressurization based on the lower pressure by controlling the valve IV from the open state to the closed state and controlling the valve X from the closed state to the open state. At this time, the valve 0 is set to the fully closed state. Accordingly, since the nitrogen gas supply amount of the ASU is limited to the upper limit, the nitrogen gas supply from the ASU to the first buffer tank 87 is stopped and limited to the lower pressure-adjusting nitrogen gas system 83, thereby preventing the source pressure at the outlet of the ASU from being lowered and the nitrogen gas supply amount from being insufficient.

When the pressure in the hopper 80 reaches the target pressure, the valves VI-1 and VI-2 are closed, and the opening degree of the valve X is decreased and maintained at a constant opening degree. The pressurization for the pulverized coal conveyance by the lower pressure adjustment nitrogen system 83 is performed by maintaining the opening degree of the valve X at a constant value. Further, the opening degree of the valve VII is also decreased to a predetermined value and maintained at a constant opening degree. Thereby, the pulverized coal is fluidized by using the fluidizing nitrogen system 84.

After the pressurization in the hopper 80 is completed, the valve 0 is controlled from the closed state to the open state, thereby pressurizing the second buffer tank 88. When the pressure of the second surge tank 88 is restored, the valve 0 is closed and the pressurization of the second surge tank 88 is ended.

[ Filter Damage detection ]

The control unit 90 detects an abnormality such as breakage of the filter 6a (see fig. 4) as follows. A filter 6a made of a porous sintered metal having strength higher than that of a metal mesh, for example, is provided at the tip of the plurality of pressurizing nozzles 6 provided in the hopper 80. If the filter 6a is broken due to abrasion, breakage due to sudden change in gas flow rate, or the like, the pressure loss in the filter 6a becomes small, but since there are many filters 6a, it is not easy to detect the occurrence of breakage of the filter 6a when one or some of the filters 6a are broken.

As a result of the inventors' keen observation, the pressure of the pressurized gas on the upstream side of the branch point at which the pressurized gas is supplied to the plurality of pressurizing nozzles 6 provided in the hopper 80 is detected by the header pressure sensor P2, and the difference from the pressure detected by the hopper pressure sensor P1 is continuously confirmed, and it is confirmed that: when the pressurized gas is supplied to the plurality of pressurizing nozzles 6, if one or some of the filters 6a among the plurality of filters 6a is broken, the differential pressure between the header pressure sensor P2 and the hopper pressure sensor P1 changes.

Therefore, the difference between the pressure detected by the hopper pressure sensor P1 and the pressure detected by the main pipe pressure sensor P2 is calculated, and when the differential pressure becomes equal to or less than a predetermined value, it is determined that the filter 6a is broken and the pressure loss is reduced, and it is determined that an abnormality is indicated. The breakage of the filter 6a is reported to an operator or an operator by a display or a voice. Thus, the operator or worker can prepare the replacement component at an appropriate timing without visually checking the filter 6a to see whether or not the filter is broken.

The predetermined value for determining the difference can be set to a differential pressure of 40% to 80% with respect to the differential pressure when the filter 6a is normal. When the predetermined value is set with high accuracy, it is preferable to set the predetermined value while checking the differential pressure and the state of the filter 6a by an experiment or the like.

As described above, according to the present embodiment, the following operational effects are exhibited.

When the first buffer tank 87 or the second buffer tank 88 becomes unusable due to a failure, an abnormality, or the like, the hopper 80 is pressurized by using the lower pressure-adjusting nitrogen gas system 83 that supplies nitrogen gas to the pulverized coal stored in the hopper 80 when the pulverized coal is supplied to the burners 126 and 127. That is, the lower pressure-regulated nitrogen gas system 83 is used for supplying pulverized coal to the burners 126 and 127 after the pressurization in the hopper 80 is completed in a normal operation, and is used for additionally supplying nitrogen gas for transporting pulverized coal for fluidizing the pulverized coal deposited in the vicinity of the wall surface of the hopper 80. The lower pressure-regulated nitrogen gas system 83 also serves as a pressurized gas supply system for pressurizing the inside of the hopper 80. Thus, even when either one of the first buffer tank 87 and the second buffer tank 88 becomes unusable, the hopper 80 can be pressurized to the target pressure.

When the valves I to IV fail and indicate an abnormality, the control unit 90 determines that the first buffer tank 87 and the second buffer tank 88 connected to the valves are unusable. Thus, the control unit 90 can determine that the first buffer tank 87 and the second buffer tank 88 are unusable, and therefore, it is not necessary for an operator or a worker to monitor the operation state to determine the operation state.

While the inside of the hopper 80 is pressurized by the lower pressure-regulated nitrogen gas system 83, nitrogen gas produced by the ASU is consumed. At this time, the valve 0 is closed, and nitrogen gas is not introduced into the first buffer tank 87 and the second buffer tank 88. Thus, since the amount of nitrogen gas supplied to the ASU is limited to the upper limit, the nitrogen gas produced by the ASU can be supplied mainly to the lower pressure adjustment nitrogen gas system 83, and a source pressure drop at the outlet of the ASU and a shortage of nitrogen gas supply can be avoided.

The porous sintered metal filter 6a provided at the tip of the plurality of pressure nozzles 6 provided in the hopper 80 may be damaged by abrasion, cracking due to a sudden change in gas flow velocity, or the like. By focusing on the differential pressure between the pressures detected by the header pressure sensor P2 of the pressurized gas in the header 86 upstream of the branch point for supplying the pressurized gas and the hopper pressure sensor P1 in the powder supply hopper, it was confirmed that: when one or some of the filters 6a among the plurality of filters 6a are broken, the differential pressure changes. Therefore, when the differential pressure between the pressure in the hopper 80 and the pressure of the pressurized gas is equal to or less than a predetermined value, it is determined that the filter 6a is broken. Thus, the operator or worker can prepare the replacement component at an appropriate timing without confirming the presence or absence of the breakage of the filter 6a by visual observation.

In the above embodiment, the pulverized coal was used as the pulverized fuel, but the present invention is not limited to this, and can be applied to other pulverized fuels such as pulverized biomass fuel and coal char.

Although the surge tank bypass system 89 is provided to assist the insufficient pressurization, the pressurization can be adjusted by the valve X of the lower pressure adjustment nitrogen system 83, and therefore the surge tank bypass system 89 may be omitted.

Description of the reference numerals

1 pulverized coal feeding hopper pressurizing device (powder feeding hopper pressurizing device)

6 pressurized nozzle

6a filter

10 coal gasification combined cycle plant (gasification combined cycle plant)

11 coal supply equipment

11a coal supply line

14 gasification furnace equipment

15 coke recovery equipment

16 gas purification equipment

17 gas turbine

18 steam turbine

19 electric generator

20 exhaust heat recovery boiler

41 compressed air supply line

42 air separation plant

43 first nitrogen supply line

45 second nitrogen supply line

46 char return line

47 oxygen supply line

49 gas generating line

51 dust collecting apparatus

52 feed hopper

53 gas discharge line

61 compressor

62 burner

63 turbine

64 rotating shaft

65 compressed air supply line

66 fuel gas supply line

67 combustion gas supply line

68 step-up machine

69 turbine

70 air exhaust line

71 vapor supply line

72 vapor recovery line

74 gas cleaning equipment

75 chimney

80 pulverized coal feeding hopper (powder feeding hopper)

81 upper segment pressurized nitrogen system

82 lower stage pressurized nitrogen system

83 lower pressure regulating Nitrogen System (gas supply System)

84 fluidized nitrogen system

85 pressurized nitrogen bypass system

86 female pipe

87 first buffer tank

87a first buffer tank side nitrogen system

87b first buffer tank side orifice

88 second buffer tank

88a second buffer tank side nitrogen system

88b second buffer tank side orifice

89 buffer tank bypass system

89b bypass side orifice

90 control part

101 gasification furnace

102 syngas cooler

110 pressure vessel

111 gasification furnace wall

115 annular portion

116 burner section

117 diffuser section

118 pressure reducer part

121 gas outlet

122 slag hopper

126 burner

127 burner

131 evaporator

132 superheater

134 coal economizer

154 inner space

156 outer space

0 buffer tank pressure regulating valve

I first buffer tank inlet stop valve

II first buffer tank outlet stop valve

III second buffer tank inlet stop valve

IV second buffer tank outlet stop valve

V buffer tank bypass cut-off valve

VI-1 upper pressurized nitrogen shut-off valve

VI-2 lower part pressurized nitrogen gas cut-off valve

VII fluidized nitrogen pressure regulating valve

VIII fluidized nitrogen stop valve

IX lower part pressure adjustment nitrogen gas trip valve

X lower pressure regulating nitrogen flow regulating valve

XI pressurized nitrogen bypass cut-off valve

P1 hopper pressure sensor (powder supply hopper pressure sensor)

P2 bus pressure sensor (pressurized gas pressure sensor).