JP7043285B2 - How to operate gasification furnace equipment, gasification combined cycle equipment and gasification furnace equipment - Google Patents

Description

The present invention relates to a gasification furnace facility, a gasification combined cycle facility, and a method for operating the gasification furnace facility.

Conventionally, as a gasification furnace facility, carbon-containing solid fuel such as coal is supplied into the gasification furnace, and the carbon-containing solid fuel is partially combusted and gasified to generate combustible gas. Equipment (coal gasification equipment) is known. Hereinafter, a case where coal is used as an example of the carbon-containing solid fuel will be described.

In the pulverized coal machine installed on the upstream side of the gasification furnace, coal is supplied, the coal is heated by dry gas, and the pulverized coal is crushed into fine particles while removing the water content in the coal. Is manufactured.

In the case of integrated coal gasification combined cycle equipment, the dry gas supplied to the pulverized coal mill may use a part of the exhaust gas discharged from the gas turbine or exhaust heat recovery steam installed on the downstream side of the gasification furnace. .. Patent Document 1 below describes that in an integrated coal gasification combined cycle facility, a part of exhaust gas extracted from a gas turbine exhaust gas or an exhaust heat recovery boiler is introduced into a pulverized coal mill as dry gas.

Japanese Unexamined Patent Publication No. 2013-17463

In a gasification combined cycle facility, it is necessary to supply pulverized coal to a gasification furnace whose inside is high pressure, so the inside of the hopper is pressurized before supplying pulverized coal to the gasification furnace. Therefore, during the pressure adjustment of the hopper, there is a timing when the pulverized coal cannot be temporarily supplied to the gasification furnace, and during that time, the pulverized coal is held in the pulverized coal bottle or the like. On the other hand, as described above, exhaust gas is used as a dry gas for pulverized coal, and when the properties of the fuel such as the type of coal are changed, the oxygen (O ₂ ) concentration in the exhaust gas changes and the oxygen concentration is high. In some cases, the pulverized coal stored in the pulverized coal dust collector or the pulverized coal bottle leads to an oxidation temperature rise. In addition, if the oxygen concentration in the exhaust gas exceeds the explosion limit, the pulverized coal may ignite and the gasification complex power generation facility may be damaged. Furthermore, if the explosion limit differs depending on the properties of the fuel such as the type of coal, the upper limit of the oxygen concentration of the exhaust gas that has already been set may change when the properties of the fuel are changed.

In the above Patent Document 1, it is disclosed that nitrogen gas is introduced into a hopper as a pressurized transport gas from an air separation device and pulverized coal is transported from the hopper to a gasifier, but a dry gas is transferred to the pulverized coal machine. It is not stated that it is necessary to adjust the oxygen concentration in the exhaust gas supplied as.

The present invention has been made in view of such circumstances, and even when the properties of the fuel such as the type of coal are changed, the present invention is stored by oxygen in the exhaust gas supplied to the pulverized fuel machine as dry gas. It is an object of the present invention to provide a method for operating a gasification furnace facility, a gasification combined cycle facility, and a gasification furnace facility capable of suppressing or preventing the occurrence of an oxidative temperature rise of pulverized fuel.

In order to solve the above problems, the following means are adopted for the operation method of the gasification furnace equipment, the gasification combined cycle equipment and the gasification furnace equipment of the present invention.
That is, the gasification complex power generation facility according to the present invention is a gasification furnace facility having a gasification furnace that produces a gas produced from a carbon-containing solid fuel, and is produced by the carbon-containing solid fuel and the gasification furnace. The exhaust gas from the gas turbine that burns at least a part of the generated gas as fuel gas is supplied, and the fine powder fuel machine that crushes the carbon-containing solid fuel and the fine powder fuel generated by the fine powder fuel machine are collected. It is provided with a dust device and an inert gas supply system that supplies the inert gas to the dust collector, and when the exhaust gas is supplied to the fine fuel machine, the dust collector is used for the fine powder fuel machine and the dust collector. When the oxygen concentration of the system up to the gasifier exceeds a predetermined threshold value, the inert gas is supplied from the inert gas supply system to the dust collector so that the oxygen concentration contained in the exhaust gas is reduced. Will be done.

According to this configuration, at least a part of the generated gas generated in the gasifier facility from the carbon-containing solid fuel is burned as fuel gas to generate exhaust gas in the gas turbine, and the pulverized fuel machine is equipped with the carbon-containing solid fuel. , The exhaust gas generated by the combustion of the fuel gas is supplied, and the carbon-containing solid fuel is crushed while being dried by the calorific value of the exhaust gas. Further, in the dust collector, the fine powder fuel produced by the fine powder fuel machine is collected. Further, when the oxygen concentration of the system from the fine powder fuel machine and the dust collector to the gasification furnace is higher than the predetermined oxygen concentration, the inert gas such as nitrogen is collected from the inert gas supply system. It is supplied to the vessel. Since the inert gas is supplied from the inert gas supply system to the dust collector, the oxygen concentration in the dust collector is reduced. As a result, oxygen in the exhaust gas supplied to the fine powder fuel machine suppresses or prevents the oxidation temperature rise of the fine powder fuel stored in the dust collector on the downstream side of the fine powder fuel machine.
For example, by setting the oxygen concentration in the dust collector based on the explosion limit set for the carbon-containing solid fuel, it is possible to reduce the possibility that the fine powder fuel will reach an oxidative temperature rise.

In the above invention, the exhaust gas discharge system through which the exhaust gas discharged from the dust collector to the outside flows, the oxygen concentration detection unit for detecting the oxygen concentration in the exhaust gas flowing through the exhaust gas discharge system, and the oxygen concentration detection. It may further include an adjusting unit for adjusting the supply amount of the inert gas supplied to the fine powder fuel machine based on the oxygen concentration detected by the unit.

According to this configuration, the exhaust gas is discharged from the dust collector to the outside through the exhaust gas discharge system. Further, the oxygen concentration detection unit detects the concentration of oxygen contained in the exhaust gas flowing through the exhaust gas discharge system, and the supply amount of the inert gas supplied to the fine fuel machine is adjusted based on the detection result. As a result, the oxygen concentration in the exhaust gas mixed with the inert gas can be detected, and the oxygen concentration in the dust collector, which tends to cause an oxidation temperature rise, can be grasped more accurately. Can be suppressed or prevented.

In the above invention, the storage device for storing the fine fuel supplied from the dust collector, the connection system in which the storage device and the exhaust gas discharge system are connected, and the connection system in which the oxygen concentration detection unit is installed are connected. The system further includes two on-off valves, one on each side of the oxygen concentration detecting unit, and by switching the opening / closing operation of the two on-off valves, the oxygen concentration detecting unit discharges the exhaust gas. The oxygen concentration inside the system and the oxygen concentration inside the storage device may be detected respectively.

According to this configuration, the connection destination of the connection system is switched by operating the on-off valve, and the oxygen concentration inside the exhaust gas discharge system and the oxygen concentration inside the storage device can be individually detected by the oxygen concentration detection unit.

In the above invention, the inert gas supply system supplies the inert gas to the fine fuel machine, and the inert gas is used inside the fine fuel machine while the operation of the fine fuel machine is stopped. It may also be used for purging.

According to this configuration, the Inactive gas supply system supplies the Inactive gas used for purging the inside of the fine fuel machine to the fine fuel machine while the operation of the fine fuel machine is stopped. The pulverized fuel machine generally has an inert gas supply system for purging in which the inert gas is supplied to the purge inside the pulverized fuel machine. Therefore, it is not necessary to newly install an inert gas supply system in the existing plant for supplying the inert gas to reduce the oxygen concentration contained in the exhaust gas during operation.

In the above invention, the supply amount of the inert gas supplied to the fine fuel machine is adjusted based on the load detection unit that detects the operating load of the gas turbine and the operating load detected by the load detecting unit. It may be further provided with an adjusting unit to be used.

According to this configuration, the load detection unit detects the operating load of the gas turbine, and the supply amount of the inert gas supplied to the fine fuel machine is adjusted based on the detection result. For example, when the operating load of the gas turbine is lower than a predetermined threshold, the oxygen concentration in the exhaust gas becomes high, so the supply amount of the inert gas is increased to increase the oxygen concentration in the exhaust gas supplied to the pulverized coal machine. Reduce. However, if there is a margin in the amount of inert gas used, it is possible to operate with a constant flow rate in order to avoid complication of control.

In the above invention, the adjusting unit for adjusting the supply amount of the inert gas supplied to the pulverized fueling machine may be further provided based on the operation process of the gasification combined power generation facility.

According to this configuration, the supply amount of the inert gas supplied to the pulverized fuel mill is adjusted based on the operation process of the gasification complex power generation facility.

In the above invention, the supply amount of the inert gas adjusted by the adjusting unit may be changed according to the type of the carbon-containing solid fuel and the volatile content in the carbon-containing solid fuel.

According to this configuration, the supply amount of the inert gas adjusted by the adjusting unit is changed according to the type of the carbon-containing solid fuel and the volatile content in the carbon-containing solid fuel, so that the explosion limit is different and the oxidation temperature rises. It is possible to more effectively suppress or prevent the occurrence of oxidative temperature rise with respect to the carbon-containing solid fuel in which the gas is likely to occur.

The gasification combined power generation facility according to the present invention includes the above-mentioned gasification furnace facility, the gas turbine that is rotationally driven by burning at least a part of the generated gas generated by the gasification furnace facility, and the gas turbine. A steam turbine that is rotationally driven by steam generated by an exhaust heat recovery boiler that introduces turbine exhaust gas discharged from the gas turbine and / or a generator that is rotationally connected to the gas turbine and / or the steam turbine is provided.

The method for operating the gasification complex power generation facility according to the present invention is to use the carbon-containing solid fuel and the production generated by the gasification furnace in a gasification furnace facility having a gasification furnace that produces a gas produced from the carbon-containing solid fuel. Exhaust gas from a gas turbine that burns at least a part of the gas as fuel gas is supplied, and a pulverized fuel machine that crushes the carbon-containing solid fuel and a dust collector that collects the pulverized fuel produced by the pulverized fuel machine. A method of operating a gasifier equipped with a device and an inert gas supply system for supplying an inert gas to the dust collector, wherein when the exhaust gas is supplied to the fine fuel machine, the fine fuel machine and the fine powder fuel machine When the oxygen concentration of the system from the dust collector to the gasifier exceeds a predetermined threshold value, the dust is collected from the inert gas supply system so that the oxygen concentration contained in the exhaust gas is reduced. The inert gas is supplied to the vessel.

According to the present invention, even when the fuel properties such as the type of coal are changed, the oxygen concentration in the exhaust gas supplied to the fine powder fuel machine as dry gas is reduced, so that the oxygen in the exhaust gas is stored as a cause. It is possible to suppress or prevent the occurrence of oxidative temperature rise of the pulverized fuel.

It is a schematic block diagram which shows the coal gasification combined cycle power generation facility which applied the gasification furnace facility which concerns on one Embodiment of this invention. It is a schematic block diagram which shows the coal supply equipment of the gasification furnace equipment which concerns on one Embodiment of this invention. It is a graph which shows the relationship between the utilization rate at the time of the normal operation of an air separation equipment, and each process of a gasification furnace equipment.

The integrated coal gasification combined cycle (IGCC) 1 to which the gasification combined cycle equipment 14 according to the embodiment of the present invention is applied uses air as a main oxidizing agent and is a gasification furnace. The equipment 14 employs an air combustion method for generating flammable gas (generated gas) from fuel. Then, the integrated coal gasification combined cycle facility 1 purifies the produced gas generated in the gasification furnace facility 14 into a fuel gas by the gas refining facility 16 and then supplies the gas to the gas turbine 17 to generate power. That is, the integrated coal gasification combined cycle facility 1 of the first embodiment is an air combustion type (air blown) power generation facility. As the fuel to be supplied to the gasification furnace facility 14, for example, a carbon-containing solid fuel such as coal is used.

As shown in FIG. 1, the integrated coal gasification combined cycle facility (gasification combined cycle facility) 1 includes a coal supply facility 11, a gasification furnace facility 14, a char recovery facility 15, a gas purification facility 16, and a gas turbine. It includes 17, a steam turbine 18, a generator 19, and an exhaust heat recovery steam generator (HRSG: Heat Recovery Steam Generator) 20.

The coal supply facility 11 is supplied with coal, which is a carbon-containing solid fuel, as raw coal, and crushes the coal with a pulverized coal machine (fine pulverized fuel machine) 4 to produce pulverized coal pulverized into fine particles. The pulverized coal produced in the coal supply facility 11 is pressurized by nitrogen gas as a transport inertia gas supplied from the air separation facility 42 described later at the outlet of the coal supply line 11a and supplied to the gasifier facility 14. Will be done. Inert gas is an inert gas having an oxygen content of about 5% by volume or less, and nitrogen gas, carbon dioxide gas, argon gas, etc. are typical examples, but it is not necessarily limited to about 5% by volume or less. ..

As shown in FIGS. 1 and 2, the coal supply facility 11 includes, for example, a raw coal bunker 3, a pulverized coal machine 4, a pulverized coal dust collector 5, a pulverized coal bottle (storage device) 6, and a pulverized coal hopper. 7 and the like.

The coal supply facility 11 collects, for example, the raw coal bunker 3 in which the coking coal is stored, the pulverized coal machine 4 for pulverizing the coking coal, and the dust in the pulverized coal pulverized by the pulverized coal machine 4. It is provided with a pulverized coal dust collector 5, a pulverized coal bottle 6 in which pulverized coal is collected from a plurality of pulverized coal dust collectors 5, a pulverized coal hopper 7 for storing the pulverized coal, and the like.

The raw coal (coal) led from the raw coal bunker 3 to the pulverized coal machine 4 is crushed into pulverized coal of several μm to several hundred μm by the pulverized coal machine 4. The pulverized coal crushed by the pulverized coal machine 4 is collected by the pulverized coal dust collector 5. The pulverized coal collected in the pulverized coal dust collector 5 is guided to the pulverized coal hopper 7 via the pulverized coal bottle 6 for storing the pulverized coal.

As described above, the pulverized coal in the pulverized coal hopper 7 is pressurized by nitrogen gas as an inertia gas for transportation, and then transferred to the gasification furnace facility 14 at a constant flow rate. Further, the pulverized coal hopper 7 is in a pressurized state by being supplied with nitrogen gas. However, when all the pulverized coal in the pulverized coal hopper 7 is supplied to the gasification furnace facility 14 and the pulverized coal hopper 7 becomes empty, it is necessary to reduce the pressure and exhaust the inside of the pulverized coal hopper 7. Therefore, the pressure in the pulverized coal hopper 7 is reduced and exhausted by opening the valve (not shown) of the reduced pressure exhaust system connected to the emptied pulverized coal hopper 7.

The gasification furnace facility 14 is supplied with pulverized coal produced by the coal supply facility 11 and is supplied with char (unreacted coal and ash) recovered by the char recovery facility 15 for the purpose of reuse. There is.

Further, a compressed air supply line 41 from the gas turbine 17 (compressor 61) is connected to the gasifier equipment 14, and a part of the compressed air compressed by the compressor 61 of the gas turbine 17 is a booster. At 68, the pressure is increased to a predetermined pressure so that the gas can be supplied to the gas turbine equipment 14. The air separation facility (ASU) 42 separates and generates nitrogen and oxygen from the air in the atmosphere, and the air separation facility 42 and the gasifier facility 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. Further, the second nitrogen supply line 45 branching from the first nitrogen supply line 43 is also connected to the gasifier facility 14, and the char return line 46 from the char recovery facility 15 is connected to the second nitrogen supply line 45. It is connected. Further, the air separation equipment 42 is connected to the compressed air supply line 41 by an oxygen supply line 47. Then, the nitrogen separated by the air separation equipment 42 is used as a transport gas for coal or char by flowing through the first nitrogen supply line 43 and the second nitrogen supply line 45. Further, the oxygen separated by the air separation facility 42 is used as an oxidant in the gasifier facility 14 by flowing through the oxygen supply line 47 and the compressed air supply line 41.

The gasification furnace equipment 14 includes, for example, a two-stage jet bed type gasification furnace (not shown). The gasification furnace facility 14 gasifies the coal (pulverized coal) and char supplied to the inside by partially burning them with an oxidizing agent (air, oxygen) to obtain a produced gas. The gasification furnace facility 14 is provided with a foreign matter removing facility 48 for removing foreign matter (slag) mixed in the pulverized coal. A gas generation line 49 for supplying the generated gas to the char recovery equipment 15 is connected to the gasifier facility 14, so that the generated gas containing the char can be discharged. In this case, by providing a thin gas cooler (gas cooler) (not shown) in the gas generation line 49, the generated gas may be cooled to a predetermined temperature and then supplied to the char recovery equipment 15.

The char collection facility 15 includes a dust collector facility 51 and a supply hopper 52. In this case, the dust collecting facility 51 is composed of one or a plurality of cyclones or porous filters, and can separate the char contained in the generated gas generated by the gasifier facility 14. Then, the generated gas from which the char is separated is sent to the gas refining facility 16 through the gas discharge line 53. The supply hopper 52 stores the char separated from the generated gas by the dust collector 51. A bin may be arranged between the dust collector 51 and the supply hopper 52, and a plurality of supply hoppers 52 may be connected to the bin. Then, the char return line 46 from the supply hopper 52 is connected to the second nitrogen supply line 45.

The gas refining facility 16 purifies the produced gas from which the char is separated by the char recovery facility 15 by removing impurities such as sulfur compounds and nitrogen compounds. Then, the gas refining facility 16 purifies the produced gas to produce a fuel gas, which is supplied to the gas turbine 17. Since the produced gas from which the char is separated still contains sulfur ( _H2S , etc.), the gas refining equipment 16 removes and recovers the sulfur content with an amine absorber or the like for effective use. do.

The gas turbine 17 includes a compressor 61, a combustor 62, and a turbine 63, and the compressor 61 and the turbine 63 are connected by a rotating shaft 64. The compressor 62 is connected to the compressed air supply line 65 from the compressor 61, the fuel gas supply line 66 from the gas refining facility 16, and the combustion gas supply line 67 extending toward the turbine 63. Is connected. Further, the gas turbine 17 is provided with a compressed air supply line 41 extending from the compressor 61 to the gasifier equipment 14, and a booster 68 is provided in the middle of the gas turbine 17. 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 facility 16 are mixed and burned to generate and burn the combustion gas. The generated combustion gas is supplied to the turbine 63. Then, the turbine 63 rotationally drives the generator 19 by rotationally driving the rotary shaft 64 with the supplied combustion gas.

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

A gas purification facility 74 is provided from the outlet of the exhaust heat recovery boiler 20 to the chimney 75.

Here, the operation of the integrated coal gasification combined cycle facility 1 of the present embodiment will be described.

In the integrated coal gasification combined cycle facility 1 of the present embodiment, when raw coal (coal) is supplied to the coal supply facility 11, the coal is pulverized into fine particles in the coal supply facility 11 to become pulverized coal. .. The pulverized coal produced in the coal supply facility 11 is supplied to the gasifier facility 14 through the first nitrogen supply line 43 by the nitrogen supplied from the air separation facility 42. Further, the char recovered by the char recovery facility 15 described later is circulated through the second nitrogen supply line 45 by the nitrogen supplied from the air separation facility 42 and supplied to the gasifier facility 14. Further, the compressed air extracted from the gas turbine 17 described later is boosted by the booster 68, and then supplied to the gasifier equipment 14 through the compressed air supply line 41 together with the oxygen supplied from the air separation equipment 42.

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

In the char recovery equipment 15, the generated gas is first supplied to the dust collecting equipment 51, so that fine chars contained in the generated gas are separated. Then, the generated gas from which the char is separated is sent to the gas refining facility 16 through the gas discharge line 53. On the other hand, the fine char separated from the generated gas is deposited on the supply hopper 52, returned to the gasifier facility 14 through the char return line 46, and recycled.

The generated gas from which the char is separated by the char recovery facility 15 is gas refined by removing impurities such as sulfur compounds and nitrogen compounds in the gas refining facility 16 to produce a fuel gas. The compressor 61 generates compressed air and supplies it to the combustor 62. The combustor 62 mixes the compressed air supplied from the compressor 61 and the fuel gas supplied from the gas refining facility 16 and burns them to generate combustion gas. By rotationally driving the turbine 63 with this combustion gas, the compressor 61 and the generator 19 are rotationally driven via the rotating shaft 64. In this way, the gas turbine 17 can generate electricity.

Then, 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 supplied to the exhaust heat recovery boiler 20, and the generated steam is used in the steam turbine 18. Supply to. In the steam turbine 18, the turbine 69 is rotationally driven by the steam supplied from the exhaust heat recovery boiler 20, so that the generator 19 can be rotationally driven via the rotary shaft 64 to generate electricity.
The gas turbine 17 and the steam turbine 18 do not have to rotate drive one generator 19 as the same axis, and may rotate drive a plurality of generators as different axes.

After that, in the gas purification equipment 74, harmful substances of the exhaust gas discharged from the exhaust heat recovery boiler 20 are removed, and the purified exhaust gas is discharged from the chimney 75 to the atmosphere.

Next, with reference to FIGS. 1 and 2, a configuration relating to adjustment of the oxygen concentration with respect to the exhaust gas used as the dry gas of the pulverized coal in the pulverized coal machine 4 will be described. The exhaust gas discharged from the turbine 63 in the gas turbine 17 is extracted by the exhaust heat recovery boiler 20, and this exhaust gas is supplied to the pulverized coal machine 4.

The oxygen (O ₂ ) concentration in the exhaust gas may change when the properties of the fuel such as the type of coal which is the raw material of the gasification furnace facility 14 are changed, or when the operating load of the gas turbine 17 is changed. Further, when the properties of the fuel such as the type of coal are changed, the explosion limit of the conventional coal type may be different and the permissible value of the oxygen concentration in the exhaust gas may be different. That is, the allowable upper limit of the oxygen concentration of the exhaust gas may change due to the difference in the explosion limit.

A plurality of pulverized coal dust collectors 5 (for example, two in this embodiment) are provided, and one end of the exhaust gas discharge line (exhaust gas detection system) 8 is connected to at least one pulverized coal dust collector 5, and the other end is connected. It is connected to the exhaust heat recovery boiler 20. The exhaust gas introduced into the pulverized coal machine 4 for drying the pulverized coal is supplied to the exhaust heat recovery boiler 20 via the exhaust gas discharge line 8 after passing through the pulverized coal dust collector 5, and the exhaust gas is discharged to the outside. To.

One end of the connection line (connection system) 9 is connected to the pulverized coal bottle 6, and the other end is connected to the exhaust gas discharge line 8. On-off valves 12 and 13 and an oxygen concentration meter (oxygen concentration detection unit) 21 are installed on the connection line 9, and the on-off valves 12 and 13 are located on the pulverized coal bottle 6 side and the exhaust gas discharge line 8 side of the oxygen concentration meter 21. One for each. By opening the on-off valve 12 on the pulverized coal bottle 6 side of the oxygen concentration meter 21 and closing the on-off valve 13 on the exhaust gas discharge line 8, the oxygen densitometer 21 can measure the oxygen concentration of the pulverized coal bottle 6. On the other hand, by closing the on-off valve 12 on the pulverized coal bottle 6 side and opening the on-off valve 13 on the exhaust gas discharge line 8, the oxygen concentration meter 21 can measure the oxygen concentration on the exhaust gas discharge line 8.

Since the pulverized coal bottle 6 is in an environment where drying progresses and the oxidative temperature rise of the pulverized coal is likely to occur, it is preferable to measure and confirm the oxygen concentration when necessary such as during trial run adjustment. On the other hand, in the pulverized coal storage portion of the pulverized coal bottle 6, the fluidity of the pulverized pulverized coal may be improved and nitrogen gas (not shown) used for pressurized transportation may be further introduced. The oxygen concentration in the pulverized coal dust collector 5 on the exhaust gas discharge line 8 side may show an oxygen concentration slightly higher than the oxygen concentration in the pulverized coal bin 6.

In the present embodiment, the oxygen concentration in the exhaust gas for drying the pulverized coal can be detected, and the oxygen concentration in the pulverized coal dust collector 5 in which the oxidative temperature rise of the pulverized coal is likely to occur can be grasped more accurately. It is possible to surely suppress or prevent the oxidative temperature rise of the pulverized coal dried by the exhaust gas. In the present embodiment, the measurement of the oxygen concentration in the pulverized coal dust collector 5 is appropriate, but the measurement is not limited to the pulverized coal dust collector 5. In the fuel side supply system of the gasification furnace facility 14, the oxygen concentration may be measured instead of the pulverized coal dust collector 5 if the oxygen concentration is high and can be detected by the oxygen concentration meter 21.

As described above, by switching the opening / closing operation of the on-off valves 12 and 13, the oxygen concentration meter 21 detects the oxygen concentration inside the exhaust gas discharge line 8 and the oxygen concentration inside the pulverized coal bottle 6, respectively. As a result, the connection destination of the connection line 9 is switched by the on-off valves 12 and 13, and the oxygen concentration inside the exhaust gas discharge line 8 and the oxygen concentration inside the pulverized coal bottle 6 can be individually detected by one oxygen concentration meter 21. Is.

When the exhaust gas is supplied to the pulverized coal machine 4, the oxygen concentration meter 21 opens and closes the exhaust gas discharge line 8 side of the connection line 9 so that the oxygen concentration in the exhaust gas passing through the pulverized coal dust collector 5 can be measured. The valve 13 is opened, and the on-off valve 12 on the pulverized coal bottle 6 side is closed. This makes it possible to easily and accurately measure the oxygen concentration of the pulverized coal dust collector 5.

The nitrogen supply line (inert gas supply system) 22 is connected to the exhaust gas supply line 23, for example, on the upstream side of the pulverized coal machine 4. The nitrogen supply line 22 may be directly connected to the air separation facility 42, or may be branched from the first nitrogen supply line 43 or the second nitrogen supply line 45. For example, the nitrogen gas generated by the air separation equipment 42 flows through the nitrogen supply line 22, and the nitrogen gas is supplied from the air separation equipment 42 to the pulverized coal mill 4. Nitrogen gas can be mixed with the exhaust gas supplied by the exhaust gas supply line 23 via the nitrogen supply line 22, and the oxygen in the exhaust gas can be diluted to reduce the oxygen concentration in the exhaust gas. Further, a flow rate adjusting valve 24 (adjusting unit) is installed in the nitrogen supply line 22.

In the present embodiment, the case where nitrogen gas is used as an example of the inert gas has been described, but the present invention is not limited to this example. The inert gas for diluting the exhaust gas may be, for example, water vapor, carbon dioxide (CO ₂ ), argon gas or the like.

While the operation of the pulverized coal machine 4 is stopped, the inside of the pulverized coal machine 4 is replaced with nitrogen gas. Therefore, the nitrogen supply line 22 may supply the nitrogen gas used for purging the inside of the pulverized coal machine 4 to the pulverized coal machine 4 while the operation of the pulverized coal machine 4 is stopped. The pulverized coal machine 4 usually has a nitrogen gas system for purging (not shown) to which nitrogen gas used for nitrogen gas replacement by purging inside the pulverized coal machine 4 is supplied. When trying to supply nitrogen gas that reduces the oxygen concentration contained in the exhaust gas to an existing plant as in the present embodiment, if the existing nitrogen gas system for purging is used, a new nitrogen supply line 22 is provided. No need to install. When the existing purge nitrogen gas system is used as the nitrogen supply line 22, the flow rate adjusting valve 24 is installed instead of the orifice installed in the purge nitrogen gas system.

In the above-mentioned example, the nitrogen supply line 22 is connected to the exhaust gas supply line 23, and the configuration in which nitrogen gas is additionally supplied to the exhaust gas on the upstream side of the pulverized coal machine 4 has been described, but the present invention is limited to this example. Not done. The nitrogen supply line 22 is connected to a line connecting the pulverized coal machine 4 and the pulverized coal dust collector 5, and nitrogen gas is added to the exhaust gas on the downstream side of the pulverized coal machine 4 and the upstream side of the pulverized coal dust collector 5. It may be supplied and mixed.

The flow rate adjusting valve 24 adjusts the supply amount of nitrogen gas flowing through the nitrogen supply line 22. The opening degree of the flow rate adjusting valve 24 is adjusted based on, for example, the oxygen concentration in the exhaust gas detected by the oxygen concentration meter 21. Alternatively, the opening degree of the flow rate adjusting valve 24 is adjusted based on the operating load of the gas turbine 17 and the operating process of the gasifier equipment 14.

One end of the exhaust gas supply line 23 is connected to the exhaust heat recovery boiler 20, and the other end is connected to the pulverized coal machine 4. Exhaust gas flows from the exhaust heat recovery boiler 20 to the pulverized coal machine 4 in the exhaust gas supply line 23. The exhaust gas extracted by the exhaust heat recovery boiler 20 is supplied to the pulverized coal machine 4 via the exhaust gas supply line 23, so that the raw coal (coal) supplied from the raw coal bunker 3 to the pulverized coal machine 4 is crushed. The pulverized coal can be dried.

Next, a method for adjusting the oxygen concentration with respect to the exhaust gas used as the dry gas according to the present embodiment will be described.

The oxygen concentration in the exhaust gas is adjusted during normal operation of the gasification furnace facility 14 (or integrated coal gasification combined cycle facility 1), that is, the pulverized coal produced by crushing the raw coal (coal) with the pulverized coal machine 4. Is supplied to the gasifier facility 14 via the pulverized coal dust collector 5 and the like. At this time, in order to dry the coal, the exhaust gas is supplied from the exhaust heat recovery boiler 20 to the pulverized coal machine 4 via the exhaust gas supply line 23.

When the properties of fuel such as the type of coal that is the raw material of the gasification furnace facility 14 are changed, the oxygen concentration in the exhaust gas changes, and the explosion limit is different, so a predetermined threshold value that becomes the allowable upper limit of the oxygen concentration in the exhaust gas. May change. Therefore, the oxygen concentration is measured by the oxygen concentration meter 21.

First, a case where the oxygen concentration meter 21 is connected to the exhaust gas discharge line 8 on the outlet side of the pulverized coal dust collector 5 will be described.
An on-off valve on the exhaust gas discharge line 8 side in the connection line 9 so that the oxygen concentration in the exhaust gas passing through the pulverized coal dust collector 5 can be measured by the oxygen concentration meter 21 when the exhaust gas is supplied to the pulverized coal machine 4. 13 is opened, and the on-off valve 12 on the pulverized coal bottle 6 side is closed.

Then, when the exhaust gas is supplied to the pulverized coal machine 4, the oxygen concentration meter 21 measures the oxygen concentration in the exhaust gas passing through the pulverized coal dust collector 5. Based on the measurement results, the opening degree of the flow rate adjusting valve 24 provided in the nitrogen supply line 22 is adjusted so that the oxygen concentration in the exhaust gas does not exceed a predetermined threshold, and nitrogen is supplied to the exhaust gas flowing through the exhaust gas supply line 23. Supply gas. As a result, when the exhaust gas is supplied to the pulverized coal machine 4 by increasing the amount of nitrogen in the exhaust gas flowing through the exhaust gas supply line 23, the pulverized coal dust collection is higher than the oxygen concentration contained in the exhaust gas at the outlet of the gas turbine 17. The concentration of oxygen contained in the exhaust gas supplied to the vessel 5 is reduced. When the oxygen concentration in the exhaust gas does not exceed a predetermined threshold value, it is not necessary to supply nitrogen gas from the nitrogen supply line 22 to the exhaust gas flowing through the exhaust gas supply line 23. However, instead of adjusting the supply of nitrogen gas each time according to the oxygen concentration by the oxygen concentration meter 21, the preset nitrogen gas may be continuously supplied to facilitate the operation of the gasification furnace facility 14.

The oxygen concentration in the exhaust gas discharged from the turbine 63 in the gas turbine 17 (exhaust gas extracted by the exhaust heat recovery boiler 20) is usually, for example, 10 to 15% by volume. For example, a predetermined threshold value may be set in consideration of the fact that the explosion limit may differ depending on the type of coal supplied.

The predetermined threshold value is set based on the explosion limit determined by, for example, the coal type of the coal to be supplied, the operating conditions of the pulverized coal mill 4, and the like. If it is assumed that coal of various coal types is supplied to the gasifier facility 14, for example, a threshold is set based on the explosion limit of the coal type each time the coal type is changed. Alternatively, the threshold may be fixed and set based on the coal type having the explosion limit with the lowest oxygen concentration among the assumed coal types. This simplifies the detection of the oxygen concentration in the exhaust gas and the adjustment to keep it below a predetermined threshold.

The above-mentioned threshold, that is, the supply amount of nitrogen gas adjusted by the flow control valve 24 is set not only by the coal type of coal but also by the volatile gas volatilized from the carbon-containing solid fuel such as coal. You may. The flammability limit oxygen concentration changes according to the volatile matter in coal. The higher the proportion of volatile matter in coal, the lower the explosive limit oxygen concentration. That is, the higher the volatile content, the higher the reactivity, and the higher the oxidation temperature is likely to occur even at a lower oxygen concentration, so that the predetermined threshold value that is the upper limit of the oxygen concentration of the exhaust gas may change. Therefore, based on the measurement result of the oxygen concentration by the oxygen concentration meter 21, the supply amount of nitrogen gas is adjusted by the flow rate adjusting valve 24, which is more effective for the carbon-containing solid fuel in which the oxidation temperature rise is likely to occur. It is possible to suppress or prevent the occurrence of oxidative temperature rise.

When the nitrogen supply line 22 is connected by the exhaust gas supply line 23 on the upstream side of the pulverized coal machine 4, new pulverized coal dust collector 5 is connected to the pulverized coal dust collector 5 while the normal operation of the pulverized coal machine 4 is stopped. Nitrogen gas used for purging inside the pulverized coal machine 4 may be supplied to the pulverized coal machine 4 via the nitrogen supply line 22 without supplying charcoal. In this case, the inside of the pulverized coal machine 4 may be purged as required. Therefore, it is not necessary to change the flow rate of the nitrogen gas supplied so that the oxygen concentration in the exhaust gas does not exceed a predetermined threshold value, and a certain amount of nitrogen gas may be supplied to the pulverized coal mill 4.

The adjustment of the oxygen concentration in the exhaust gas may be performed based on the operating load of the gas turbine 17 instead of measuring the oxygen concentration in the exhaust gas.
Specifically, first, when the exhaust gas as a dry gas is supplied to the pulverized coal machine 4, the load detecting unit (not shown) detects the operating load of the gas turbine 17. Based on the detection result, the nitrogen supply may be set in advance so that the oxygen concentration in the exhaust gas does not exceed a predetermined threshold value, and may be stored in, for example, a storage unit (not shown). The opening degree of the flow rate adjusting valve 24 provided in the nitrogen supply line 22 is adjusted to supply nitrogen gas to the exhaust gas flowing through the exhaust gas supply line 23.
In this case, the opening degree of the flow rate adjusting valve 24 may be set based on the relationship between the operating load of the gas turbine 17 and the opening degree of the flow rate adjusting valve 24 previously recorded in the storage unit (not shown).

The inventors have obtained the finding that when the operating load of the gas turbine 17 is low, the oxygen concentration in the exhaust gas tends to be high. Based on this, when it is necessary to increase the supply amount of nitrogen gas and reduce the oxygen concentration so as not to exceed the predetermined threshold value of the oxygen concentration set from the explosion limit when the operating load of the gas turbine 17 is low. Therefore, the opening degree of the flow rate adjusting valve 24 is increased. On the other hand, when the operating load of the gas turbine 17 is high, the oxygen concentration in the exhaust gas is low, so that the supply amount of nitrogen gas may be reduced and the opening degree of the flow rate adjusting valve 24 is reduced.

Further, in the gasification furnace facility 14 (or the integrated coal gasification combined cycle facility 1), the oxygen concentration in the exhaust gas may be adjusted in a process in which the usage rate of the nitrogen gas generated in the air separation facility 42 is low. good. FIG. 3 shows the relationship between the usage rate of nitrogen gas when the normal operation of the air separation equipment 42 is set to the upper limit (100%) when starting the gasification furnace equipment 14, and each process of the gasification furnace equipment 14. Is shown. As shown in FIG. 3, from the gas turbine fuel switching to the gas turbine fuel switching completion of the gas turbine equipment 14, the gas turbine 17 is under a low operating load, and the oxygen concentration in the exhaust gas tends to be high. be. On the other hand, during this period, the usage rate of nitrogen gas generated by the air separation facility 42 is low, and since there is a margin in supplying nitrogen gas, a large amount of nitrogen gas is supplied to the pulverized coal dust collector 5. , Reduce the oxygen concentration in the pulverized coal dust collector 5. On the other hand, on the contrary, in the process during normal operation of the gasifier equipment 14 in which the operating load of the gas turbine 17 is high, the oxygen concentration in the exhaust gas is low, so that the supply amount of nitrogen gas may be reduced. .. Since the usage rate of the nitrogen gas generated by the air separation equipment 42 is high, the supply amount of nitrogen can be reduced. The inventors have confirmed that even with this method, the oxygen concentration in the exhaust gas is maintained so as not to exceed a predetermined threshold value.
In this way, by adjusting the oxygen concentration in the exhaust gas in the process where the usage rate of the nitrogen gas generated by the air separation equipment 42 is low, the maximum amount of nitrogen that can be produced by the air separation equipment 42 is not increased. The oxygen concentration in the exhaust gas can be effectively reduced.

More specifically, as shown in FIG. 3, the step in which the usage rate of the nitrogen gas generated in the above-mentioned air separation facility 42 is low is, for example, the gasification furnace facility 14 (or the integrated coal gasification combined cycle facility 1). At the time of start-up, after the warming of the gasifier equipment 14 is completed, the combustion of the gas turbine 17 is started using not only the auxiliary fuel for starting but also the gas generated in the gasifier equipment 14, and further started. This is the process of stopping the supply of auxiliary fuel and starting the combustion of the gas turbine 17 only by the gas from the gasification furnace facility 14.

In the process during this period, the operating load of the gas turbine 17 is low, and the usage rate of nitrogen gas generated by the air separation facility 42 is also low. At this timing, the oxygen concentration of the pulverized coal dust collector 5 may be reduced with a margin by supplying a large amount of nitrogen gas to the pulverized coal dust collector 5.

It is desirable to mix a large amount of nitrogen gas with the exhaust gas at the above-mentioned timing at the time of starting, but the present invention is not limited to this example. However, until the gasification furnace warming is completed, the gas turbine 17 is started by using the starting auxiliary fuel instead of the gas generated in the gasifier. Combustion of the gas turbine 17 only by the gas generated from the gas turbine equipment 14 during the period from the completion of the start of the gas turbine 17 to the completion of the warming of the gas turbine equipment 14 and during the normal operation of the gas turbine equipment 14. During normal operation after starting the above, the usage rate of nitrogen gas generated by the air separation facility 42 is relatively high. Therefore, even if the supply of nitrogen gas to the pulverized coal dust collector 5 is reduced or reduced to zero, the oxygen concentration of the pulverized coal dust collector 5 does not exceed a predetermined threshold value.

As described above, according to the present embodiment, when the exhaust gas is supplied to the pulverized coal machine 4, if the oxygen concentration of the pulverized coal dust collector 5 is higher than a predetermined threshold value, the nitrogen gas is collected from the nitrogen supply line 22. It is supplied to the dust collector 5. Since the nitrogen gas is mixed with the exhaust gas and supplied from the nitrogen supply line 22 to the pulverized coal dust collector 5, the oxygen concentration in the pulverized coal dust collector 5 is reduced. As a result, oxygen in the exhaust gas supplied to the pulverized coal machine 4 as a dry gas suppresses the oxidative temperature rise of the pulverized coal stored in the pulverized coal dust collector 5 on the downstream side of the pulverized coal machine 4. Be prevented.

Further, in the above-described embodiment, the IGCC provided with a coal gasification furnace that uses coal as a fuel to generate flammable gas from pulverized coal has been described as an example, but contains other carbons such as high-grade coal and low-grade coal. It can be applied even if it is a solid fuel, and it may be a biomass used as an organic resource derived from renewable organisms, not limited to coal. For example, thinned wood, waste wood, drifting wood, grasses, etc. , Waste, sludge, tires and recycled fuels (pellets and chips) made from these can also be used. The gasifier equipment of the present invention is applicable not only to power generation but also to a gasifier for a chemical plant to obtain a desired chemical substance.

In this embodiment, the tower type gasification furnace has been described as the gasification furnace of the gasification furnace equipment 14, but even if the gasification furnace is a crossover type gasification furnace, the vertical up and down of each device in the gasification furnace. The same can be achieved by replacing the direction so as to match the gas flow direction of the generated gas.

Further, in the above-described embodiment, the case where the oxygen concentration meter 21 is connected to the exhaust gas discharge line 8 on the outlet side of the pulverized coal dust collector 5 has been described, but the oxygen concentration meter 21 is connected to the outlet of the gas turbine 17. May be connected. In this case, the oxygen concentration in the exhaust gas before the nitrogen gas is mixed with the exhaust gas is measured. Therefore, the opening degree of the flow rate adjusting valve 24 is set based on the relationship between the oxygen concentration at the outlet of the gas turbine 17 and the opening degree of the flow rate adjusting valve 24, which is determined based on a predetermined threshold value. ..

1: Coal gasification combined cycle equipment (gasification combined cycle equipment)
3: Raw coal bunker 4: Fine coal machine (fine fuel machine)
5: Fine coal dust collector (dust collector)
6: Fine pulverized coal bottle (storage device)
7: Fine coal hopper 8: Exhaust gas discharge line (exhaust gas discharge system)
9: Connection line (connection system)
11: Coal supply equipment 11a: Coal supply line 12: On-off valve 13: On-off valve 14: Gasification furnace equipment 15: Char recovery equipment 16: Gas purification equipment 17: Gas turbine 18: Steam turbine 19: Generator 20: Exhaust heat Recovery boiler 21: Oxygen meter (oxygen concentration detector)
22: Nitrogen supply line (inert gas supply system)
23: Exhaust gas supply line 24: Flow rate adjustment valve (adjustment unit)
41: Compressed air supply line 42: Air separation equipment 43: First nitrogen supply line 45: Second nitrogen supply line 46: Char return line 47: Oxygen supply line 48: Foreign matter removal equipment 49: Gas generation line 51: Dust collection equipment 52: Supply hopper 53: Gas discharge line 61: Compressor 62: Combustor 63: Turbine 64: Rotating shaft 65: Compressed air supply line 66: Fuel gas supply line 67: Combustion gas supply line 68: Booster 69: Turbine 70 : Exhaust gas line 71: Steam supply line 72: Steam recovery line 73: Water recovery device 74: Gas purification equipment 75: Chimney

Claims (9)

It is a gasification furnace facility having a gasification furnace that produces generated gas from carbon-containing solid fuel.
A fine powder fuel machine in which the carbon-containing solid fuel and exhaust gas from a gas turbine that burns at least a part of the generated gas generated in the gasification furnace as fuel gas are supplied to crush the carbon-containing solid fuel.
A dust collector that collects the fine fuel produced by the fine fuel machine, and
An inert gas supply system that supplies the inert gas to the dust collector,
Equipped with
When the exhaust gas is supplied to the fine powder fuel machine, if the oxygen concentration of the system to the gasification furnace via the fine powder fuel machine and the dust collector exceeds a predetermined threshold value, the oxygen contained in the exhaust gas A gasifier facility in which the inert gas is supplied from the inert gas supply system to the dust collector so that the concentration is reduced. An exhaust gas discharge system through which the exhaust gas discharged from the dust collector to the outside flows,
An oxygen concentration detector for detecting the oxygen concentration in the exhaust gas flowing through the exhaust gas discharge system,
An adjusting unit that adjusts the supply amount of the inert gas supplied to the fine fuel machine based on the oxygen concentration detected by the oxygen concentration detecting unit.
The gasifier equipment according to claim 1, further comprising. A storage device for storing the fine fuel supplied from the dust collector, and
A connection system that connects the storage device and the exhaust gas discharge system and in which the oxygen concentration detection unit is installed.
In the connection system, two on-off valves installed on both sides of the oxygen concentration detection unit, one on each side, and
Further prepare
The gasification furnace facility according to claim 2, wherein the oxygen concentration detecting unit detects the oxygen concentration inside the exhaust gas discharge system and the oxygen concentration inside the storage device by switching the opening / closing operation of the two on-off valves. .. The inert gas supply system supplies the inert gas to the fine fuel machine.
The gasification furnace facility according to any one of claims 1 to 3, wherein the inert gas is also used for purging the inside of the fine powder fuel machine while the operation of the fine powder fuel machine is stopped. A load detection unit that detects the operating load of the gas turbine, and
An adjusting unit that adjusts the supply amount of the inert gas supplied to the fine fuel machine based on the operating load detected by the load detecting unit.
The gasification furnace equipment according to claim 1. The gasification furnace equipment according to claim 1, further comprising an adjusting unit for adjusting the supply amount of the inert gas supplied to the fine powder fuel machine based on the operation process of the gasification furnace equipment. The gas according to claim 2, 5 or 6, wherein the supply amount of the inert gas adjusted by the adjusting unit is changed according to the type of the carbon-containing solid fuel and the volatile content in the carbon-containing solid fuel. Gasification furnace equipment. The gasifier equipment according to any one of claims 1 to 7.
The gas turbine that is rotationally driven by burning at least a part of the generated gas generated in the gasification furnace equipment, and the gas turbine.
A steam turbine that is rotationally driven by steam generated by an exhaust heat recovery steam that introduces turbine exhaust gas discharged from the gas turbine, and
With the gas turbine and / or the generator rotationally connected to the steam turbine,
Gasification combined cycle power generation equipment. In a gasifier facility having a gasifier that produces produced gas from carbon-containing solid fuel, from a gas turbine that burns at least a part of the carbon-containing solid fuel and the produced gas generated in the gasifier as fuel gas. The exhaust gas of the above is supplied, and the fine powder fuel machine that crushes the carbon-containing solid fuel, the dust collector that collects the fine powder fuel generated by the fine powder fuel machine, and the inert gas are supplied to the dust collector. It is a method of operating a gasifier facility equipped with an inert gas supply system.
When the exhaust gas is supplied to the fine powder fuel machine, if the oxygen concentration of the system to the gasification furnace via the fine powder fuel machine and the dust collector exceeds a predetermined threshold value, the oxygen concentration contained in the exhaust gas A method of operating a gasifier facility that supplies the inert gas from the inert gas supply system to the dust collector so as to reduce the amount of gas.

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