JP5688569B2 - Gasifier - Google Patents

Description

  The present invention relates to a gasification furnace, and more particularly, to a gasification furnace that cools and discharges molten slag obtained by melting ash in a carbon-containing solid material.

  For example, Patent Document 1 discloses that a carbon-containing solid raw material and a gasifying agent, for example, coal is partially burned with air, and the coal is gasified with heat generated by the partial combustion to generate a product gas. A vertical gasification furnace has been proposed in which the ash content therein is melted to flow down as molten slag. And the cooling part which stored the cooling water is connected to the bottom part of a gasification furnace, and the molten slag which flowed down is dropped to cooling water from the hole provided in the lower part of the gasification furnace, and it is made to discharge | emit. In particular, according to this document, in order to prevent the molten slag that has been dropped from scattering and adhering to the side wall of the cooling unit, water or water vapor is jetted from a nozzle provided on the side wall of the cooling unit, A wall of water or water vapor is made around the fall path. According to this, since the scattered slag which has been scattered can collide with the wall of water or water vapor and be dropped into the cooling water, it is possible to suppress the molten slag from adhering to the side wall of the cooling unit.

Japanese Utility Model Publication No. 6-85343

  However, the technique described in Patent Document 1 has a problem that when the injected water collides with the molten slag, the amount of water discharged from the gasification furnace increases by the amount of the injected water, and the amount of wastewater treatment increases. There is.

  On the other hand, since the density of water vapor is small, it is difficult to drop molten slag, and a large amount of water vapor is injected, and there is a problem that a large amount of water vapor enters the gasification furnace and the temperature inside the gasification furnace also decreases. .

  The problem to be solved by the present invention is to remove the molten slag adhering to the side wall of the cooling section and to reduce the temperature drop in the gasification furnace.

To solve the above problems, the gasification furnace of the present invention, a carbon-containing solid material the produced gas produced by the reaction and the gasification gas agent as well as discharged from the gas discharge port, ash carbon-containing solids in the raw material A gasification part that discharges the molten slag from the slag discharge port, a cooling part that cools the molten slag flowing down from the gasification part by dropping it into the cooling water stored in the bottom part, and a cooling part provided along the side wall characterized in that a nozzle for intermittently injecting the inert gas in the gasification reaction toward the liquid surface of the cooling water.

  According to this, since gas can be injected toward the molten slag adhering to the side wall of the cooling unit, the adhering molten slag can be removed from the side wall of the cooling unit. And since the injection quantity of gas can be adjusted according to the adhesion amount etc. of molten slag, and the quantity of the gas which penetrate | invades a gasification part can be decreased, the temperature fall of a gasification furnace can be reduced.

  In this case, the gas injection amount can be further reduced by intermittently injecting the gas.

  Further, the gas to be injected can be a gas inert to the gasification reaction, such as nitrogen gas or product gas. In particular, when the generated gas is injected, the generated gas generated in the gasification unit is not diluted by the gas injected in the cooling unit, and thus it is possible to prevent the heat amount of the generated gas from being lowered.

  Also, when providing a plurality of nozzles, the side wall of the cooling unit is divided into a plurality of regions in the horizontal direction, nozzles are provided for each region, gas is intermittently injected for each region, and the amount of gas injection is reduced. Can be reduced.

On the other hand, if there is a problem in the operation of the gasifier if the amount of stored coolant is too large, stop the gasifier operation when the water level exceeds the set water level by measuring the coolant level Means may be provided. In this case, when the molten slag adhered by jetting gas is dropped from the side wall into the cooling water, the liquid level of the cooling water undulates and temporarily rises above the set water level , and the stop means operates the gasifier. May stop. Therefore, by stopping the stopping means while gas is being injected, it is possible to prevent the gasification furnace from stopping, and the gasification furnace can be stably operated for a long time.

  ADVANTAGE OF THE INVENTION According to this invention, the molten slag adhering to the side wall of a cooling part can be removed, and the temperature fall in a gasification furnace can be reduced.

It is a schematic block diagram of the gasification furnace of Embodiment 1 of this invention. It is a horizontal sectional view of the soot blow nozzle position of FIG. It is an enlarged view of the soot blow nozzle of FIG. It is the figure which illustrated control of the control means. It is a schematic block diagram of the gasification plant containing the gasification furnace of Embodiment 2 of this invention. It is a schematic block diagram of the gasification furnace of Embodiment 3 of this invention.

Hereinafter, the present invention will be described based on embodiments.
(Embodiment 1)
1 is a schematic configuration diagram of a gasification furnace according to Embodiment 1, FIG. 2 is a horizontal sectional view of the position of the soot blow nozzle in FIG. 1, and FIG. 3 is an enlarged view of the soot blow nozzle in FIG. As shown in the figure, the gasification furnace 1 according to the first embodiment is a cylindrical vertical gasification furnace 1, in which a discharge port for product gas (not shown) is formed at the top of the furnace, and is shown at the bottom of the furnace. There is no slag outlet. A gasification unit 3 is formed in the upper part of the gasification furnace 1, and a cooling unit 5 is formed in the lower part.

  The gasification unit 3 gasifies the carbon-containing solid material with a gasifying agent to generate a product gas 4, and melts ash in the carbon-containing solid material to form a molten slag 8. A burner 7 is provided on the side wall of the gasification unit 3. The burner 7 is supplied with a carbon-containing solid material and a gasifying agent such as pulverized coal 9 and oxygen 11 from a supply facility (not shown). The burner 7 is configured to inject pulverized coal 9 and oxygen 11 to form a swirling flow in the gasification unit 3. Note that oxygen-enriched air can be used in place of the oxygen 11.

The cooling unit 5 cools the molten slag 8 flowing down from the gasification unit 3 by dropping it into the cooling water 13 stored at the bottom. A water cooling pipe 14 through which water flows in the vertical direction is embedded in the side wall of the cooling unit 5. Adjacent water-cooled tubes 14 are connected by a membrane bar 16. A part of the side surface of the water cooling tube 14 is exposed in the cooling unit 5. An auxiliary burner 15 is provided in the upper part of the cooling unit 5. The auxiliary burner 15 is supplied with fuel 17 such as heavy oil, natural gas, and purified product gas 4 and oxidant 19 such as air from a supply facility (not shown). A slag crusher 21 is provided in the cooling water 13 below the cooling unit 5. The slag crusher 21 pulverizes the granulated slag 23 that has settled in the cooling water 13 to a size that can be discharged from the discharge port at the bottom of the gasification furnace 1. A motor 25 is connected to the slag crusher 21. The motor 25 is configured to rotationally drive the slag crusher 21 at a predetermined rotational speed.

  A slag tap 27 is provided between the gasification unit 3 and the cooling unit 5. The slag tap 27 is formed with an inclined portion 28 that is inclined downward from the side wall of the gasification furnace 1 toward the axial center. A hole 34 is formed at the axial center of the gasification furnace 1 of the slag tap 27 to allow the molten slag 8 flowing down the side wall of the gasification unit 3 to drop into the cooling water 13.

  Next, the characteristic structure of the gasification furnace 1 of Embodiment 1 is demonstrated. A soot blow nozzle 31 is provided on the side wall of the cooling unit 5 immediately below the slag tap 27. The soot blow nozzle 31 is divided into a plurality of regions, for example, regions 30a, 30b, 30c, and 30d in the horizontal direction at the position 29 on the side wall of the cooling unit 5, and a plurality of soot blow nozzles 31 are provided for each region. The soot blow nozzle 31 is provided at the same height along the circumferential direction of the side wall of the cooling unit 5. The soot blow nozzle 31 is supplied with a pressurized gas, for example, nitrogen gas, from a supply facility (not shown). At the tip of the soot blow nozzle 31, an injection port 36 for injecting nitrogen gas toward the liquid surface of the cooling water 13 along the side wall of the cooling unit 5 is formed. A pipe 32 through which nitrogen gas flows is connected to the rear end side of the soot blow nozzle 31. The piping 32 is branched and formed, one for each region, and one piping 32 can be connected to a plurality of soot blow nozzles 31 in each region. Each pipe 32 is provided with an adjustment valve 33 that adjusts the flow rate of nitrogen gas to a predetermined flow rate, and a shut-off valve 35 that is provided upstream of the adjustment valve 33 and that blocks the flow path in the pipe 32. Control means 37 is connected to the shutoff valve 35 to control the opening and closing of the shutoff valve 35.

  Operation | movement of the gasification furnace 1 of Embodiment 1 comprised in this way is demonstrated. The pulverized coal 9 supplied from the burner 7 into the gasification unit 3 is partially burned with oxygen 11 to generate heat. With this heat, pulverized coal 9 and oxygen 11 are gasified to generate a product gas 4 containing hydrogen and carbon monoxide. Furthermore, the temperature of the gasification part 3 is maintained above the melting point of the ash in the pulverized coal 9, and the ash in the pulverized coal 9 is melted to form a molten slag 8. The molten slag 8 adheres to the side wall of the gasification unit 3 by centrifugal force due to the swirling flow in the gasification unit 3 and flows down by weight. The molten slag 8 that has flowed down is guided to the hole 34 along the inclined portion 28 of the slag tap 27 and falls from the hole 34 to the cooling unit 5 by its own weight. At this time, the molten slag 8 is heated by hot air from the auxiliary burner 15 and easily flows down the hole 34. The dropped molten slag 8 is rapidly cooled by the cooling water 13 and solidified, and is pulverized by thermal stress to become a granulated slag 23. The granulated slag 23 settles in the cooling water 13, is pulverized to a predetermined particle size by the slag crusher 21, and is discharged from the gasifier 1.

  Next, the characteristic operation of the first embodiment will be described. The molten slag 8 dropped from the hole 34 falls while spreading in the cooling unit 5 by the swirl flow in the gasification unit 3 or hot air blown from the auxiliary burner 15. Therefore, a part of the molten slag 8 adheres to the side wall of the cooling unit 5. Since the temperature of the side wall of the cooling unit 5 is kept low by the water cooling pipe 14, the molten slag 8 is solidified on the side wall of the cooling unit 5 while adhering. The scattered molten slag 8 adheres to the solidified molten slag 8, and the molten slag 8 gradually grows on the side wall of the cooling unit 5. Further, when the adhered molten slag 8 receives hot air from the auxiliary burner 15, the surface of the molten slag 8 is sintered and the strength is increased. The molten slag 8 often falls off due to its own weight, but the molten slag 8 whose temperature has been lowered and strength has been increased is not easily crushed by the cooling water 13. And since the solidified molten slag 8 settles in the cooling water 13 with a large lump, the slag crusher 21 and the slag discharge port may be blocked. Therefore, the high-pressure nitrogen gas sprayed from the soot blow nozzle 31 is caused to collide with the adhered molten slag 8, and the adhered molten slag 8 is dropped into the cooling water 13 and removed from the side wall of the cooling unit 5.

  Moreover, the control means 37 opens and closes the shut-off valve 35 connected to each of the regions 30a, 30b, 30c, and 30d in order to intermittently inject nitrogen gas from the soot blow nozzle 31. Here, the nitrogen gas injection time (T1), the injection stop time (T2), and the injection cycle (T3) will be described with reference to FIG. The control means 37 opens only the shutoff valve 35 of the pipe 32 connected to the region 30a during T1, for example, for 2 seconds. Thereby, nitrogen gas is injected from the soot blow nozzle 31 provided in the area 30a for 2 seconds. Then, the control means 37 closes the shutoff valve 35 after T1 has elapsed, and stops the injection of nitrogen gas in the region 30a. Then, after T2 elapses after closing the shutoff valve 35, for example, after 10 seconds, only the shutoff valve 35 of the pipe 32 connected to the region 30b is opened for 2 seconds, and nitrogen is discharged from the soot blow nozzle 31 provided in the region 30b. Inject gas. After injecting nitrogen gas for 2 seconds, the shutoff valve 35 is closed. This operation is similarly performed in the areas 30c and 30d. That is, the control means 37 performs control that injects nitrogen gas in the order of 30a, 30b, 30c, and 30d, and does not inject nitrogen gas in another region while one region injects nitrogen gas. And the control means 37 can perform this control in the period of T3, for example, a 6-hour period, can inject nitrogen gas intermittently, and can remove the adhered molten slag 8 from the side wall of the cooling unit 5 regularly.

  According to this, since the molten slag 8 can be periodically removed from the side wall of the cooling unit 5, it is possible to prevent the slag crusher 21 and the slag discharge port from being blocked by the grown molten slag 8 and to stably operate the gasifier 1. it can. And since nitrogen gas can be injected intermittently and the injection amount of nitrogen gas can be decreased, the amount of nitrogen gas which penetrates into the gasification part 3 can be reduced, and the temperature drop of the gasification part 3 can be reduced. Furthermore, since the injection amount of nitrogen gas can be reduced, dilution of the product gas 4 with the injected nitrogen gas can be reduced, and the heat amount of the product gas 4 can be maintained high.

  Moreover, since the molten slag 8 adhering to the side wall of the cooling unit 5 has a weak adhesive force and can be easily removed, the amount of nitrogen gas injected can be reduced.

  In the first embodiment, the injection of nitrogen gas is intermittent, but the control means 37 is connected to the regulating valve 33, the opening degree of the regulating valve 33 is adjusted, and the flow rate of the nitrogen gas is appropriately increased or decreased. Nitrogen gas can be continuously injected.

  In the first embodiment, a plurality of soot blow nozzles 31 are controlled by one shutoff valve 35, but a shutoff valve 35 can be provided in each soot blow nozzle 31.

  Moreover, the installation position and number of the soot blow nozzles 31 are not limited to those in the first embodiment, and can be appropriately selected according to the size of the gasification furnace 1, the amount of ash contained in coal, adhesion, and the like.

  Further, the gas injected from the soot blow nozzle 31 is not limited to nitrogen gas, and a gas that is inert to the gasification reaction, a gas that does not react with the product gas 4, or the like can be used.

(Embodiment 2)
The schematic block diagram of the gasification furnace of Embodiment 2 is shown in FIG. The difference between the second embodiment and the first embodiment is that a part of the generated gas is injected from the soot blow nozzle 31 instead of the nitrogen gas. Furthermore, char contained in the product gas 4 discharged from the gasification furnace 1 is collected and supplied to the gasification furnace 1 for gasification. Since other configurations are the same as those of the first embodiment, the same reference numerals are given and description thereof is omitted. In addition, although FIG. 5 illustrated the gasification plant containing the gasification furnace of Embodiment 2 in order to make description easy to understand, this embodiment is not limited to the illustrated gasification plant.

  A heat recovery boiler 45 that recovers the heat of the generated gas 4 is connected to the top of the gasification furnace 1 through a pipe. Inside the heat recovery boiler 45, a heat transfer tube 47 through which a heat medium that exchanges heat with the product gas 4 flows is provided. A char recovery means 49 for recovering char in the product gas 4 is connected to the bottom of the heat recovery boiler 45 via a pipe. The char recovery means 49 is constituted by, for example, a bag filter 51 and a cyclone 53 so that the char can be separated from the product gas 4. The char recovery means 49 can supply the char to the char burner provided on the side wall of the gasification furnace 1 (not shown) via the hopper 54. The product gas 4 from which the char has been separated is introduced into the gas purification means 55. A part of the purified product gas 57 discharged from the gas purification means 55 is branched so that the product gas 57 can be supplied to the soot blow nozzle 31 via the gas compression means 59.

  The operation of the second embodiment configured as described above will be described. The product gas 4 generated in the gasification furnace 1 is heat recovered by the heat recovery boiler 45 and introduced into the char recovery means 49. The char recovery means 49 separates the char from the product gas 4 by passing the product gas 4 through the bag filter 51 and the cyclone 53. The separated char is stored in the hopper 54 and supplied to the gasification section 3 of the gasification furnace 1 by a supply means (not shown) provided at the bottom of the hopper 54, and the char and the gasifying agent are reacted to generate the product gas 4. Generate.

  On the other hand, the product gas 4 from which the char has been separated is introduced into the gas purification means 55, the sulfur compound and nitrogen compound in the product gas are removed, and the purified product gas 57 is discharged. Part of the product gas 57 is branched and introduced into the gas compression means 59, and the remainder is used as a raw material gas or a fuel gas for a gas turbine or the like. The product gas 57 introduced into the gas compression means 59 is pressurized and injected from the soot blow nozzle 31.

  According to this, it is possible to remove the molten slag 8 adhering by injecting the generated gas 57 from the soot blow nozzle 31, so that the generated gas 4 is diluted by the gas injected by the cooling unit 5 and the amount of heat of the generated gas 4 is reduced. Can be prevented.

(Embodiment 3)
The principal part block diagram of the gasification furnace of Embodiment 3 is shown in FIG. The third embodiment differs from the first embodiment in that a flow rate control means 61 for controlling the flow rate of the cooling water 13 supplied to the bottom of the cooling unit 5 is provided. Furthermore, a water level control means 63 for measuring the water level of the cooling water 13 and controlling the water level to the set water level, and a stop means 65 for stopping the operation of the gasifier when the water level exceeds the set water level are provided, and nitrogen gas is supplied. The stopping means 65 is stopped during the injection. Since other configurations are the same as those of the first embodiment, the same reference numerals are given and description thereof is omitted. FIG. 6 omits the description of the auxiliary burner 15 and the outer wall of the gasification furnace 1 to make the illustration easier to understand.

  The flow rate control means 61 measures the flow rate of the cooling water 13 supplied to the gasifier 1 measured by the flow meter 67, adjusts the opening of the adjustment valve 69 according to the measured flow rate, and supplies the cooling water to a constant flow rate. The cooling water 13 that can be supplied to the cooling unit 5 and discharged together with the slag can be replenished.

  The water level control means 63 includes a water level measurement means 71 that measures the water level of the cooling water 13 and an adjustment valve 73 that adjusts the discharge amount of the cooling water 13 from the gasification furnace 1. The water level control means 63 opens the adjustment valve 73 according to the water level of the cooling water 13 measured by the water level measuring means 71 to drain the cooling water 13 and controls the water level of the cooling water 13 within a predetermined range. As the water level measuring means 71, a known water level sensor can be applied. For example, a communication pipe that communicates the upper and lower water levels of the cooling unit 5 may be provided, and a sensor that detects the water level in the communication pipe using an electromagnetic float or the like may be used. The adjustment valve 73 is provided in a pipe for draining the cooling water 13 and can adjust the discharge amount of the cooling water 13 by adjusting the opening of the valve.

  Control means 37 for opening and closing the shutoff valve 35 and water level measuring means 71 are connected to the stop means 65. The stopping means 65 stops the operation of the gasifier 1 when the water level measured by the water level measuring means 71 exceeds the set water level. Further, the stop means 65 stops the operation of stopping the operation of the gasification furnace 1 while the control means 37 opens the shut-off valve 35 and injects nitrogen gas from the soot blow nozzle 31. Further, the stopping means 65 resumes the stopped operation when the control means 37 closes the shutoff valve 35 and the injection of nitrogen gas from the soot blow nozzle 31 stops.

  According to this, since the operation of the stop means 65 is stopped while the nitrogen gas is being injected, the injected nitrogen gas and the molten slag 8 that has fallen undulate the water surface of the cooling water 13 to cause the cooling water 13. Even if the water level exceeds the set water level, the gasification furnace 1 can be prevented from stopping. That is, the injection of nitrogen gas or the falling molten slag 8 raises the water surface of the cooling water 13 temporarily, and it is not necessary to stop the operation of the gasifier 1. The furnace 1 can be operated stably for a long time.

  While the nitrogen gas is being injected from the soot blow nozzle 31, the operation of the water level control means 63 opening the adjustment valve 73 and discharging the cooling water 13 is also stopped, and the discharge amount of the cooling water 13 is increased by the nitrogen gas injection. Can be prevented.

DESCRIPTION OF SYMBOLS 1 Gasification furnace 3 Gasification part 4 Product gas 5 Cooling part 8 Molten slag 31 Soot blow nozzle 35 Shut-off valve 65 Stop means 71 Water level measurement means

Claims (5)

A carbon-containing solid material the produced gas produced by the reaction and the gasification gas agent as well as discharged from the gas discharge port, the molten slag of ash of the carbon-containing solids in the raw material and the gasification unit to discharge from the slag discharge port , cooling unit and the gas toward the liquid surface of the coolant along the sidewalls provided on the cooling unit for cooling by dropping the cooling water accumulated the molten slag flows down from the gasification unit to the bottom gasification furnace comprising a nozzle for intermittently injecting an inert gas into reaction. In the gasifier according to claim 1,
The gasification furnace, wherein the gas is nitrogen gas or the product gas. In the gasifier according to claim 1,
The gasification furnace characterized by the said nozzle being equipped with the control means which injects the said gas intermittently. In the gasification furnace according to claim 3,
The gasification is characterized in that a side wall of the cooling unit is divided into a plurality of regions in the horizontal direction, the nozzles are provided for each region, and the control means controls the gas injection of the nozzles for each region. Furnace. In the gasification furnace according to claim 3 or 4,
Measuring means for measuring the water level of the cooling water, and stopping means for stopping the operation of the gasifier when the water level of the cooling water exceeds a set water level,
A gasification furnace characterized in that the operation of the stopping means is stopped while the nozzle is injecting the gas.

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