JP6327698B2 - Circulating fluidized bed gasification system - Google Patents

Description

  The present invention relates to a circulating fluidized bed gasification system in which a gasified raw material containing moisture is introduced into a fluidized bed gasification furnace.

  In recent years, fluidized bed gasifiers that use gasification raw materials of hydrocarbon resources such as coal, biomass, garbage, and sewage sludge and supply the generated gas as combustible gas have been developed.

  The fluidized bed gasifier forms a fluidized bed by supplying water vapor as a gasifying agent while heating a gasification raw material with heated fluidized medium particles such as sand. And the fluidized bed gasification apparatus gasifies the gasification raw material with a fluidized bed, and manufactures gasification gas.

  As a fluidized bed gasifier, for example, as disclosed in Patent Document 1, a fluidized bed combustion furnace that heats fluidized medium particles separately from a fluidized bed gasification furnace is provided, and the fluid heated by the fluidized bed combustion furnace A two-column circulating fluidized bed gasification system that supplies medium particles to a fluidized bed gasification furnace is known.

JP 2013-136655 A

  Here, the gasification raw material thrown into the fluidized bed gasification furnace includes, for example, a hydrous gasification raw material containing a large amount of water such as sewage sludge. Hereinafter, the hydrous gasification raw material refers to a gasification raw material containing water as a gasification raw material of hydrocarbon resources such as coal, biomass, garbage, sewage sludge and the like. When such a hydrous gasification raw material is put into a fluidized bed gasification furnace, the temperature of the fluidized bed is lowered, and there is a possibility that the temperature necessary for gasification of the gasification raw material which is an endothermic reaction cannot be maintained.

  Therefore, when such a hydrous gasification raw material is put into a fluidized bed gasification furnace, it is necessary to reduce the moisture by drying in advance, and thus a drying device is required. At this time, the water obtained from the hydrous gasification raw material was discarded, leaving room for improvement from the viewpoint of effective use of resources.

  Therefore, the present invention is a circulating fluidized bed gasification system in which a hydrous gasification raw material is introduced into a fluidized bed gasification furnace, and reduces moisture before introducing the gasified raw material containing water into the fluidized bed gasification furnace. It aims at providing the circulating fluidized bed gasification system which can utilize the water | moisture content effectively.

The circulating fluidized bed gasification system of the present invention separates the fluidized medium particles heated by the fluidized bed combustion furnace from the exhaust gas, the fluidized bed combustion furnace for heating the fluidized medium particles and discharging the fluidized medium particles together with the exhaust gas from above. A particle separator, a fluidized bed gasification furnace that gasifies a hydrous gasification raw material in the presence of water vapor by heat of fluidized medium particles separated by the particle separator, and the fluidized bed Water vapor supply means for supplying water vapor to the gasification furnace. Heat generated from the fluidized bed combustion furnace is transferred to the hydrous gasification raw material before being supplied to the fluidized bed gasification furnace to generate water vapor from the hydrous gasification raw material, and generated in the heat exchanger Steam generation means having a steam supply passage for guiding the steam to the steam supply means, and transporting the hydrous gasification raw material before being supplied to the fluidized bed gasification furnace from one end side to the other end side. in the raw material conveying pipe, cage by a screw conveyor arranged therein, that is configured to carry moisture gasified raw material while sealing the interior of the the external material transport pipe in water gasification feedstock as a feature The heat exchanger is a double pipe type provided with the raw material transport pipe and an outer pipe that is arranged so as to surround the raw material transport pipe and through which the exhaust gas from the fluidized bed combustion furnace flows. The material transfer pipe is at the other end There is connected to the steam supply passage, the screw conveyor can be configured to pitch the other end is wider than the pitch from one end side to the center portion.
The heat exchanger is connected to the raw material transport pipe at the top, the steam supply path is connected to the top, and the raw material supply pipe for supplying the hydrous gasification raw material to the fluidized bed combustion furnace is connected to the bottom. A vertical raw material conveyance path in which a part of an exhaust gas pipe that guides the exhaust gas from the particle separator is disposed along an internal flow path is provided in the vertical raw material conveyance path. The hydrous gasification raw material can be stored in the lower side, and the hydrous gasification raw material can be conveyed to the raw material supply pipe by a screw conveyor disposed at the lower part of the flow path.

  The circulating fluidized bed gasification system of the present invention can reduce moisture before using the gasified raw material containing water to the fluidized bed gasification furnace, and can effectively use the moisture.

It is a schematic block diagram which shows the circulating fluidized bed gasification system of this invention. It is a schematic block diagram which shows a part of modification of a circulating fluidized bed gasification system.

  Hereinafter, a mode example (hereinafter referred to as an example) for carrying out the present invention will be described with reference to FIG. FIG. 1 is a schematic configuration diagram showing a circulating fluidized bed gasification system 1 of the present invention. A circulating fluidized bed gasification system 1 includes a fluidized bed combustion furnace 2, a cyclone 3 (particle separator), a fluidized bed gasification furnace 4, a raw material supply pipe 5 (raw material supply means), and an air diffuser 6 (steam). Supply means) and steam generation means 7.

  The fluidized bed combustion furnace 2 is charged with fluidized medium particles 12 and char 11 from the fluidized bed gasification furnace 4 through the overflow pipe 8. The fluidized bed combustion furnace 2 is supplied with air 10 from the lower part, heats the fluidized medium particles 12 by combustion of the char 11, and discharges the fluidized medium particles 12 together with the exhaust gas 13 from the upper part. Here, the fluid medium particles 12 are, for example, cinnabar sand, zircon sand, alumina or the like. The exhaust gas 13 including the fluid medium particles 12 is guided to the cyclone 3.

  The cyclone 3 separates the fluidized medium particles 12 heated by the fluidized bed combustion furnace 2 from the exhaust gas 13. Then, the separated fluid medium particles 12 are guided to the fluidized bed gasification furnace 4 by the downcomer 9. The exhaust gas 13 from which the fluid medium particles 12 are separated is guided to the next step by the exhaust gas pipe 21.

  The fluidized bed gasification furnace 4 includes an air diffuser 6 at the lower part. For example, water vapor 14 from the boiler B is supplied to the air diffuser 6 as a gasifying agent. And the diffuser 6 fluidizes the fluidized medium particles 12 of the fluidized bed gasification furnace 4 by supplying the water vapor 14 to form the fluidized bed 15.

  The fluidized bed gasification furnace 4 has a raw material supply pipe 5 on one side. The raw material supply pipe 5 supplies the hydrous gasification raw material 16 into the fluidized bed gasification furnace 4. The hydrous gasification raw material 16 supplied to the fluidized bed gasification furnace 4 receives the heat of the fluidized medium particles 12 and gasifies in the presence of water vapor 14 to generate a gasified gas 17. That is, the hydrous gasification raw material 16 undergoes an endothermic reaction with the heat of the fluidized bed 15 and the water vapor 14 and is gasified to generate a gasified gas 17.

  The fluidized bed gasification furnace 4 has an overflow pipe 8 on the other side. The overflow pipe 8 guides the fluidized medium particles 12 and the char 11 constituting the fluidized bed 15 to the fluidized bed combustion furnace 2. Here, the char 11 refers to an unreacted gasification raw material.

  The steam generating means 7 includes a heat exchanger 18 and a water vapor supply channel 20. The heat exchanger 18 moves the heat of the exhaust gas 13 from the fluidized bed combustion furnace 2 to the hydrous gasification raw material 16 before being supplied to the fluidized bed gasification furnace 4 to generate water vapor 14 from the hydrous gasification raw material 16. .

  The heat exchanger 18 is a double pipe type and performs heat exchange inside and outside the double pipe. The heat exchanger 18 includes an outer pipe 19 that is located outside through which the high-temperature exhaust gas 13 from the fluidized bed combustion furnace 2 is flowed, and a raw material conveyance pipe 22 that is located on the inner side where the hydrous gasification raw material 16 is conveyed. ing.

  The outer pipe 19 is connected to the exhaust gas pipe 21, and the high temperature exhaust gas 13 is flowed through it. The outer pipe 19 is disposed so as to surround the raw material transport pipe 22 and transmits the heat of the exhaust gas 13 to the hydrous gasification raw material 16 of the raw material transport pipe 22.

  The raw material transport pipe 22 is charged with the hydrous gasification raw material 16 from one end side. Moreover, the raw material conveyance pipe | tube 22 has the opening part 23 for letting the water vapor | steam 14 pass to the upper part of the other end side. A screw conveyor 24 is rotatably disposed inside the raw material transport pipe 22 and is driven by a motor M to transport the hydrous gasification raw material 16 from one end side to the other end side. Here, the raw material conveyance pipe | tube 22 conveys the hydrous gasification raw material 16 so that it may become a counterflow with the waste gas 13 which flows through an outer side pipe | tube.

  In the screw conveyor 24, the pitch on the other end side is wider than the pitch from one end side to the central portion. As a result, the screw conveyor 24 carries the hydrous gasification raw material 16 in a dense state in the central portion of the raw material transport pipe 22 where heat exchange is performed. At this time, the hydrous gasification raw material 16 conveyed in a dense state seals the outside and the inside of the raw material transport pipe 22 so that the outside air does not flow through the raw material transport pipe 22 to the water vapor supply channel 20. Further, the screw conveyor 24 carries the hydrous gasification raw material 16 in a sparse state in the portion of the raw material transport pipe 22 where the opening 23 is formed.

  Therefore, the water-containing gasification raw material 16 is heat-transferred from the exhaust gas 13 in a dense state, and the water vapor 14 is released in a sparse state. Then, the water vapor 14 generated from the hydrous gasification raw material 16, that is, the water vapor 14 generated in the heat exchanger 18 is guided to the diffuser 6 through the water vapor supply channel 20 connected to the opening 23. It has become. Here, the steam supply channel 20 is provided with a blower 25 in the middle of the channel so that the steam is guided to the diffuser 6.

  According to the circulating fluidized bed gasification system 1 of the present invention, the heat exchanger 18 transfers the heat of the exhaust gas 13 to the hydrous gasification raw material 16 before being supplied to the fluidized bed gasification furnace 4. Water vapor 14 is generated from 16. Thus, moisture can be reduced from the hydrous gasification raw material 16 before being charged into the fluidized bed gasification furnace 4. Further, the water vapor 14 generated in the heat exchanger 18 is guided to the diffuser 6 through the water vapor supply channel 20 and used for gasification. For this reason, the generated water vapor 14 (water) can be used effectively, and the amount of the water vapor 14 supplied from the boiler B can be reduced.

  For example, when coal having a water content of 20% and a carbon content of 70% is gasified at a water vapor / carbon molar ratio of 1.2 in the fuel, the circulating fluidized bed gasification system 1 of the present invention can completely fuel the fuel. If the water vapor 14 generated therein is effectively used as a gasifying agent, the amount of the water vapor 14 of about 20% can be reduced.

  A modification of the circulating fluidized bed gasification system 1 will be described with reference to FIG. FIG. 2 is a schematic configuration diagram showing a part of a modified example of the circulating fluidized bed gasification system 1. Since the basic configuration of the modified example of the circulating fluidized bed gasification system 1 is the same as that of the above embodiment except for the heat exchanger 28, the same reference numerals are given to the same configurations as those of the above embodiment. The description which overlaps with the description of the above embodiment is omitted.

  The heat exchanger 28 includes a vertical raw material conveyance path 32, an exhaust gas pipe 31, and a screw conveyor 34. In the vertical raw material conveyance path 32, the raw material conveyance pipe 22 is connected to the upper part, the raw material supply pipe 5 is connected to the lower end, a part of the exhaust gas pipe 31 is disposed along the internal flow path, and the screw conveyor 34. Is disposed at the bottom of the flow path.

  The hydrous gasification raw material 16 is densely conveyed by the screw conveyor 24 in the raw material conveyance pipe 22. This seals between the raw material transport pipe 22 and the vertical raw material transport path 32, and prevents outside air from being guided to the vertical raw material transport path 32 and flowing into the water vapor supply flow path 20. And when the hydrous gasification raw material 16 is guide | induced to the upper position from the raw material conveyance pipe | tube 22, the vertical raw material conveyance path 32 will guide the hydrous gasification raw material 16 below with dead weight.

  Then, when the hydrous gasification raw material 16 is introduced from the raw material transfer pipe 22, the heat exchanger 28 is once stored on the lower side of the vertical raw material transfer path 32 and then transferred to the raw material supply pipe 5 by the screw conveyor 34. The Thereby, the heat exchanger 28 seals the raw material supply pipe 5 and the vertical raw material conveyance path 32, and prevents the gasified gas 17 generated in the fluidized bed gasification furnace 4 from flowing out to the vertical raw material conveyance path 32. It is like that.

  The heat exchanger 28 is once stored on the lower side of the vertical raw material transfer path 32 after the hydrous gasification raw material 16 is introduced from the raw material transfer pipe 22. For this reason, the water-containing gasification raw material 16 secures a sufficient time for heat exchange with the high-temperature exhaust gas 13 flowing through the exhaust gas pipe 31 and releases the water vapor 14.

  The water vapor 14 released from the hydrous gasification raw material 16 is guided to the diffuser 6 through the water vapor supply flow path 20 connected to the top of the vertical raw material transfer path 32. Also in this modified example of the circulating fluidized bed gasification system 1, the same effect as the circulating fluidized bed gasification system 1 is achieved.

  In addition, the circulating fluidized bed gasification system 1 of this invention is not limited only to the above-mentioned Example. For example, the steam generated by the circulating fluidized bed gasification system 1 of the present invention can be used not only for the gasifying agent of the fluidized bed gasification furnace 4, but also for steam used in the gasifier and its peripheral devices. Moreover, although the steam generation means 7 was demonstrated in the aspect connected to the raw material supply pipe 5, it is not limited to this, You may connect directly to the fluidized bed gasification furnace 4 not via the raw material supply pipe 5. The circulating fluidized bed gasification system 1 of the present invention can be variously modified without departing from the gist of the present invention.

1 Circulating fluidized bed gasification system 2 Fluidized bed combustion furnace 3 Cyclone (particle separator)
4 Fluidized bed gasifier 6 Air diffuser (steam supply means)
7 Steam generating means 12 Fluid medium particles 13 Exhaust gas 14 Water vapor 16 Hydrous gasification raw material 17 Gasification gas 18 Heat exchanger 20 Steam supply channel 28 Heat exchanger

Claims (2)

A fluidized bed combustion furnace for heating the fluidized medium particles and discharging the fluidized medium particles together with the exhaust gas from above;
A particle separator for separating the fluidized medium particles heated by the fluidized bed combustion furnace from the exhaust gas;
A fluidized bed gasification furnace for gasifying a hydrous gasification raw material in the presence of water vapor by heat of fluidized medium particles separated by the particle separator;
A circulating fluidized bed gasification system comprising a steam supply means for supplying steam to the fluidized bed gasification furnace,
A heat exchanger for transferring the heat of the exhaust gas from the fluidized bed combustion furnace to the hydrous gasification raw material before being supplied to the fluidized bed gasification furnace, and generating water vapor from the hydrous gasification raw material,
Further comprising a steam generating means having a steam supply flow path for guiding the steam generated in the heat exchanger to the steam supply means,
In the raw material transport pipe for transporting the hydrous gasification raw material before being supplied to the fluidized bed gasification furnace from one end side to the other end side, by the screw conveyor disposed inside, the outside and the inside of the raw material transport pipe Is configured to transport the hydrous gasification raw material while sealing with the hydrous gasification raw material,
The heat exchanger is a double pipe type provided with the raw material transport pipe and an outer pipe that is disposed so as to surround the raw material transport pipe and through which exhaust gas from the fluidized bed combustion furnace flows.
The other end side of the raw material transport pipe is connected to the water vapor supply channel,
The circulating fluidized bed gasification system characterized in that the screw conveyor has a pitch at the other end wider than a pitch from one end to the center. A fluidized bed combustion furnace for heating the fluidized medium particles and discharging the fluidized medium particles together with the exhaust gas from above;
A particle separator for separating the fluidized medium particles heated by the fluidized bed combustion furnace from the exhaust gas;
A fluidized bed gasification furnace for gasifying a hydrous gasification raw material in the presence of water vapor by heat of fluidized medium particles separated by the particle separator;
A circulating fluidized bed gasification system comprising a steam supply means for supplying steam to the fluidized bed gasification furnace,
A heat exchanger for transferring the heat of the exhaust gas from the fluidized bed combustion furnace to the hydrous gasification raw material before being supplied to the fluidized bed gasification furnace, and generating water vapor from the hydrous gasification raw material,
Further comprising a steam generating means having a steam supply flow path for guiding the steam generated in the heat exchanger to the steam supply means,
In the raw material transport pipe for transporting the hydrous gasification raw material before being supplied to the fluidized bed gasification furnace from one end side to the other end side, by the screw conveyor disposed inside, the outside and the inside of the raw material transport pipe Is configured to transport the hydrous gasification raw material while sealing with the hydrous gasification raw material,
The heat exchanger has an upper part connected to the raw material transport pipe, a top part connected to the water vapor supply path, a lower end connected to a raw material supply pipe for supplying a hydrous gasification raw material to the fluidized bed combustion furnace, A vertical raw material conveyance path in which a part of an exhaust gas pipe for guiding the exhaust gas from the particle separator along the flow path is disposed,
In the vertical raw material conveyance path, the hydrous gasification raw material charged from the raw material conveyance pipe is stored in the lower side, and the hydrous gasification raw material is conveyed to the raw material supply pipe by a screw conveyor disposed at the lower part of the flow path. A circulating fluidized bed gasification system characterized by comprising:

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