JP5554508B2 - Slag discharge device and slag discharge method - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a slag discharge device and a slag discharge method, and in particular, continuously removes granulated slag produced in a gasification furnace that gasifies waste such as fine solid carbon fuel and municipal waste represented by coal. It is related with the slag discharge device for making it discharge.

  2. Description of the Related Art Conventionally, there is known a coal gasification system in which pulverized coal fuel such as coal is guided to a gasification furnace and partially combusted, and a generated gas generated by the combustion is extracted and used for power generation such as a gas turbine. In such a gasification system, for example, pulverized coal fuel is supplied into the furnace together with an oxidizer and is gasified in a high-temperature atmosphere of 1300 ° C. or higher. Heated to generate molten slag. The molten slag flows down in the furnace, is guided into a storage hopper in which cooling water is stored, and is cooled and solidified. The cooled and solidified slag is finely pulverized by a slag crusher installed in the storage hopper and temporarily stored together with cooling water. Then, the slag is extracted from the gasification furnace together with the cooling water, and the slag container outside the furnace (slag lock) It is also called a hopper.)

  On the other hand, since the inside of the slag container is communicated with the gasification furnace and is in a pressurized state, the inlet / outlet of the slag container is closed to release the pressure in the container and perform depressurization. Next, only the outlet side of the slag container is opened, and the slag is discharged together with the cooling water from the depressurized slag container. The slag discharged from the slag container is guided to the slag separation tank, and the slag is separated and recovered. The slag collected in this way is mixed with concrete and reused as materials for construction and civil engineering.

  As described above, the slag discharge mechanism in which the slag discharged from the gasification furnace is stored in the slag container together with the cooling water, and the slag container is depressurized and then discharged outside the system is widely known. (For example, refer to Patent Document 1).

JP 2000-328069 A

  By the way, in the conventional slag discharge mechanisms including Patent Document 1, the slag discharge system for temporarily storing the slag discharged from the gasification furnace in the slag container and discharging it after depressurization is one system. For this reason, for example, when depressurizing the inside of the slag container, the piping connecting the slag container and the gasification furnace is shut off, and at that time, in the cooling water stored in the storage hopper in the gasification furnace, Slag generated by the operation of the gasifier is finely pulverized and precipitated. In this state, when slag is discharged from the slag container and the shut-off pipe is opened and slag is extracted from the bottom of the gasifier, the slag temporarily collected at the bottom of the storage hopper will be removed when the slag is extracted. The dynamic pressure accompanying the pressure difference at the time of a stop is applied, and consolidation of slag advances by repeating this operation. Therefore, for example, bridging of the slag is promoted in the slag discharge part of the storage hopper, and there is a possibility that the slag is blocked.

  In particular, if the amount of slag generated in the gasification furnace increases or the slag discharge part of the storage hopper is blocked, the level meter (water level meter) of the cooling water is buried in the slag, making it difficult to detect the water level. In this case, the flow of slag deteriorates due to a decrease in the amount of cooling water discharged accompanying the slag. As a result, the slag discharge part of the storage hopper and the slag container, and the piping connecting the storage hopper and the slag container There is a risk of slag clogging.

  This invention makes it a subject to discharge stably the slag crushed in the gasification furnace.

In order to solve the above problems, the present invention includes a gasification unit that gasifies solid fuel and generates molten slag, and a storage hopper that stores cooling water that granulates molten slag flowing down from the gasification unit. In a slag discharge device comprising a gasification furnace and a slag container that communicates with the bottom of the gasification furnace and stores and discharges slag discharged from a storage hopper, the slag container is slag discharged from the gasification furnace Switching means for switching between the piping systems, pressure release means for releasing the pressure in the slag container, and slag discharging means for discharging the slag stored in the slag container A control means for controlling the operation of the pressure release means, the slag discharge means and the switching means, a slag bunker for collecting the slag discharged from each slag container, and a slag Weight detection means for continuously or intermittently detecting the weight of the slag collected by the tanker and cooling water supply means for supplying cooling water to the slag container are provided, and the control means increases the weight of the slag by the weight detection means. When the rate is less than the specified value, the cooling water is supplied into the slag container that discharges the slag, and after a certain period of time, the cooling water is simultaneously supplied to the upper pipes of the plurality of connected slag containers, and the water is stored in the storage hopper. The piping system is switched and controlled so that crushed slag is continuously discharged .

  According to this, by switching the piping system for discharging slag in the gasification furnace at a predetermined timing, the slag is discharged through any piping system without blocking the flow path for discharging the slag from the gasification furnace. It becomes possible to do. As a result, slag retention in the storage hopper can be suppressed and slag clogging can be prevented, so that slag can be discharged stably, and the reliability of continuous operation of the gasifier can be ensured.

  Further, in all the piping systems, the discharged slag can be guided to the slag container and depressurized, and the depressurized slag can be discharged, so that the slag can be easily discharged.

  Also, when the slag weight increase rate detected by the weight detection means is less than the specified value, that is, when the slag bunker weight increase rate decreases and does not reach the specified value, the slag is clogged in the slag container or the pipe ahead. Therefore, it is possible to eliminate clogging of the slag by forcibly supplying the cooling water to the slag container that discharges the slag. Conventionally, the slag flow condition has been detected by detecting the sound and vibration of the slag flow pipe, but the amount of slag generated varies depending on the coal ash content and gasifier load. Is required. Accordingly, there is a feature that the clogging can be clearly determined according to the variation by detecting the weight as in the present invention.

  In the slag discharge method using such a slag discharge device, the present invention switches the piping system so that the slag crushed by the storage hopper is continuously discharged. That is, the switching timing of the piping system is controlled so that one of the slag containers is always in communication with the storage hopper via the piping system. Thereby, since the slag crushed by the storage hopper can be continuously discharged, clogging of the slag can be suppressed and stable discharge can be performed.

  More specifically, first, only one piping system is opened, slag is stored in a storage hopper communicating with this piping system, and other piping systems are controlled to open before this piping system is closed. . If it does in this way, since either piping system will always be in the open state, it can prevent the accumulation of the slag to the storage hopper.

  ADVANTAGE OF THE INVENTION According to this invention, the slag crushed in the gasification furnace can be discharged | emitted stably.

It is a block diagram of one Embodiment of the slag discharge device to which this invention is applied. It is a figure explaining one Example of valve operation | movement of the slag discharge device to which this invention is applied. It is a diagram which shows the weight change of the slag bunker which collect | recovers slag in the slag discharge device formed by applying this invention.

  Hereinafter, an embodiment of a slag discharge device to which the present invention is applied will be described with reference to the drawings. FIG. 1 is a configuration diagram of a slag discharge device to which the present invention is applied. FIG. 2 is a view for explaining the valve operation of the slag discharger to which the present invention is applied. FIG. 3 is a diagram showing a change in weight of a slag bunker that collects slag in a slag discharger to which the present invention is applied.

  In this embodiment, a coal gasification facility that uses coal pulverized coal fuel as a solid fuel will be described as an example. However, this fuel is not limited to pulverized coal fuel, for example, when organic waste such as municipal waste is used as fuel. It is also possible to apply to.

  Coal gasification equipment is roughly composed of pretreatment equipment and gasification furnace. In the pretreatment facility, the coal is pulverized into pulverized coal, the pulverized coal is introduced into an atmospheric hopper, and is supplied to the gasifier in a state pressurized by, for example, a lock hopper system. The pulverized coal supplied to the gasification furnace is partially burned and gasified.

  As shown in FIG. 1, the slag discharge device of the present embodiment includes a gasification furnace 1, slag lock hoppers 9 and 10 that become slag containers, a slag separation tank 19, a slag conveyor 20, a slag bunker 21, a load cell 22, and a control device 37. It is configured with.

  In the gasification furnace 1, a pulverized coal fuel ejected from a pulverized coal fuel nozzle 1a is mixed with an oxidant such as air or oxygen to gasify, and a cooling water disposed below the gasification unit. A storage hopper 61 is provided, and the molten slag generated from the gasification section flows down in the furnace and is crushed by the cooling water of the storage hopper 61. The storage hopper 61 is provided with the slag crusher 2 so that the slag that is crushed in the cooling water is further finely pulverized (for example, a particle size of about 2 μm). In the vicinity of the water surface of the storage hopper 61, a level meter 36 for detecting the coolant level is installed.

  The gasifier 1 is connected with a water supply pipe 41 for supplying cooling water to the storage hopper 61 and a drain pipe 42 for draining the cooling water, and the drain pipe based on the detected water level detected by the level meter 36. The flow rate adjustment valve 25 arranged in 42 is adjusted so that the cooling water amount of the storage hopper 61 is adjusted. The water supply pipe 41 is provided with a cooling water supply valve 27, and the drainage pipe 42 is provided with a cooling water drain valve 24 and a flow rate adjustment valve 26 on the upstream side and the downstream side of the flow rate adjustment valve 25, respectively. .

  A pipe for discharging slag is connected to the bottom of the gasification furnace 1, that is, the bottom of the storage hopper 61, and the slag lock hoppers 9 are respectively connected to the ends of the upper pipes 3 and 4 branched from the pipe. , 10 are connected. One ends of slag discharge pipes 34 and 35 are connected to the bottoms of the slag lock hoppers 9 and 10, respectively, and the other ends of the slag discharge pipes 34 and 35 are connected to the slag separation tank 19.

  Hereinafter, in the present embodiment, the slag discharged from the gasifier 1 is supplied to the slag separation tank 19 through the upper pipe 3, the slag lock hopper 9, and the slag discharge pipe 34 as the A system, A system path in which the slag discharged from the converter 1 is supplied to the slag separation tank 19 via the upper pipe 4, the slag lock hopper 10, and the slag discharge pipe 35 is distinguished as a B system.

  The slag separation tank 19 is connected to the lower end of the slag conveyor 20, and a slag bunker 21 is provided below the upper end of the slag conveyor 20. Thereby, the slag collected in the slag separation tank 19 is separated from the cooling water, conveyed by the slag conveyor 20, dropped onto the slag bunker 21 and collected. The slag bunker 21 is provided with a load cell 22 so that the weight of the slag bunker 21 including the recovered slag is detected continuously or intermittently. The weight of the slag bunker 21 detected by the load cell 22 is converted into an electric signal and output to the control device 37, and the control device 37 that receives the signal controls the operation of each operation valve. Here, only the weight of the collected slag may be detected as the weight detected by the load cell 22, and the detection result may be output to the control device 37.

Next, the piping configuration related to the A system and the B system will be described in detail.
In the A system, the upper cut valve 5 and the upper seal valve 6 are disposed from the upstream side in the upper pipe 3, and the lower cut valve 15 and the lower seal valve 16 are disposed from the upstream side in the slag discharge pipe 34. . On the other hand, in the B system, the upper cut valve 7 and the upper seal valve 8 are arranged from the upstream side in the upper pipe 4, and the lower cut valve 17 and the lower seal valve 18 are arranged from the upstream side in the slag discharge pipe 35. It is installed. In each system, pipes 44 and 45 branched from the water supply pipe 43 are connected to the upstream side of the upper cut valves 5 and 7 of the upper pipes 3 and 4, respectively, while the slag lock hoppers 9 and 10 are Pipes 47 and 48 branched from the water supply pipe 46 are connected to each other.

  The water supply pipe 43 is provided with a cooling water supply valve 28, and the pipes 44 and 45 are provided with cooling water supply valves 29 and 30, respectively. One ends of the pipes 47 and 48 are branched and connected in the circumferential direction of the side surface of the hopper constricted conically toward the bottom of the slag lock hoppers 9 and 10, for example. The piping 47 and 48 are provided with cooling water supply valves 11 and 12, respectively.

  Also, decompression pipes 49 and 50 are connected to the downstream side of the upper seal valve 6 of the upper pipe 3 in the A system and the downstream side of the upper seal valve 8 of the upper pipe 4 of the B system, respectively. After the pipes merge to form one pipe, they are connected to the slag separation tank 19. Decompression shut-off valves 13 and 14 are disposed in the decompression pipes 49 and 50, respectively.

  Overflow pipes 51 and 52 are connected to the upper portions of the slag lock hoppers 9 and 10, respectively. These pipes merge to form one pipe, which is then sandwiched between the flow rate adjustment valves 25 and 26 of the drainage pipe 42. It is designed to merge with the specified position. Overflow pipes 51 and 52 are respectively provided with overflow water shut-off valves 31 and 32, and a shut-off valve 33 is provided in a pipe formed by joining these pipes. The shutoff valve 33 is controlled based on the detected water level detected by the level meter 36.

  Next, the operation of the slag discharging apparatus configured as described above will be described. In this embodiment, the slag is discharged by first using the A system to discharge the slag, and then switching from the A system to the B system to discharge the slag.

  The pulverized coal supplied to the gasification furnace 1 is partially burned at 1300 ° C. or higher in the gasification section to generate molten slag. This molten slag flows down in the furnace, flows into the cooling water of the storage hopper 61, and is crushed. Thereafter, the particle size is further finely pulverized by the slag crusher 2.

  Here, the valve operation in the slag conveyance will be described with reference to FIG. First, the upper cut valve 5, the upper seal valve 6, the overflow water shut-off valve 31 of the A system are opened, the lower cut valve 15 and the lower seal valve 16 are closed, and the upper cut valve 7 and the upper seal valve 8 of the B system are closed. By closing, only the A system is in the slag acceptance state. Thereby, the slag finely pulverized by the storage hopper 61 is accompanied by the cooling water, flows through the upper pipe 3, and is stored in the slag lock hopper 9. After a certain amount of slag is stored in the slag lock hopper 9, the upper cut valve 5 and the upper seal valve 6 are closed. At this time, the overflow water shutoff valve 31 is also closed.

  Here, before closing the upper cut valve 5 and the upper seal valve 6 of the A system, the upper cut valve 7 and the upper seal valve 8 of the B system are opened, and the slag is locked by the slag lock hopper 9 and the slag lock hopper 10 for a certain period of time. To accept. Thereby, slag is continuously discharged from the storage hopper 61. Thereafter, the slag acceptance is switched from the A system to the B system.

  Before receiving the slag in each system, the cooling water supply valves 11 and 12 are opened, and the slag lock hopper 9 and the slag lock hopper 10 are filled with the cooling water supplied from the pipes 47 and 48, respectively. The cooling water supply valves 28 and 29 are opened when the slag is received from the A system, the cooling water supply valves 28 and 30 are opened when the slag is received from the B system, and the cooling is performed when switching from the A system to the B system. All the water supply valves 28, 29 and 30 are opened. In this way, by flowing the cooling water through the upper pipes 3 and 4 and storing the cooling water in the slag lock hoppers 9 and 10, until the slag is discharged from the gasification furnace 1 and stored in the slag lock hopper. During this time, the slag flows through the upper pipe 3 while maintaining high fluidity, and is collected in the slag lock hoppers 9 and 10 without causing clogging of the slag. Further, the slag does not stay locally in the slag lock hopper.

  Next, the acceptance of the slag of the A system is finished, and the slag lock hopper 9 is depressurized. In this case, the upper cut valve 5 and the upper seal valve 6 are closed, and the slag acceptance of the slag lock hopper 9 is stopped. At the same time, the cooling water supply valve 29 is also closed. Thereafter, the pressure release shut-off valve 13 is opened, and the pressure in the slag lock hopper 9 is released.

  When the depressurization ends, slag is discharged from the slag lock hopper 9 by opening the lower cut valve 15 and the lower seal valve 16. At this time, since the slag is accompanied by the cooling water and flows through the slag discharge pipe 34, the slag is transported to the slag separation tank 19 by forming a smooth flow without causing clogging of the slag. Further, when the slag is discharged, the cooling water supply valve 11 can be opened to supply the cooling water to the slag lock hopper 9. Thereby, obstruction | occlusion of the slag discharge part of the slag lock hopper 9 and the slag discharge piping 34 can be prevented more reliably.

  When all the slag stored in the slag lock hopper 9 is discharged, the lower cut valve 15 and the lower seal valve 16 are closed, the cooling water shut-off valve 11 is opened, the cooling water is stored in the slag lock hopper 9, and the water is full. And Thereafter, the depressure cutoff valve 13 and the cooling water supply cutoff valve 11 are closed.

  On the other hand, in the B system, slag acceptance into the slag lock hopper 10 is started by the same valve operation as in the A system before the slag acceptance in the A system is completed, and switching to the B system is completed at the end of the acceptance of the slag in the A system. Is done. Then, the same operation as the A system is performed in the B system, and the slag reception of the A system is started again before the completion of the slag reception of the B system, and then the A system and the B system are switched. In this way, an alternating switching operation between the A system and the B system is performed.

  On the other hand, the slag discharged from the slag lock hoppers 9 and 10 is temporarily stored in the slag separation tank 19 together with the cooling water, and the precipitated slag is transferred by the slag conveyor 20. As a result, the cooling water and the slag are separated. The slag transferred by the slag conveyor 20 falls on the slag bunker 21 and is collected. The weight of the slag bunker 21 is detected continuously or intermittently by the load cell 22 together with the collected slag.

  Since the weight of the slag bunker 21 detected by the load cell 22 includes the total weight of the collected slag, as shown in FIG. 3, it increases linearly with time. Here, if the slag paid out by the A system and the slag paid out by the B system are recorded alternately and the slag is discharged normally, as shown in (1) and (2) of the figure In addition, although the weight increase per hour (weight increase rate) is constant, as shown in (3) of the figure, when the weight increase rate of the slag bunker 21 is not constant, that is, when the weight increase rate is less than the specified value It is determined that the slag discharge from the slag lock hopper 9 of the A system is abnormal, that is, the slag is clogged. This determination is made by the control device 37 based on the detection signal output from the load cell 22.

  When the control device 37 determines that the slag discharge of the system A is abnormal, the control device 37 increases the amount of cooling water supplied to the slag lock hopper 9 by increasing the valve opening of the cooling water supply valve 11 in order to eliminate clogging of the slag. Alternatively, when cooling water is not supplied to the slag lock hopper 9, the cooling water is supplied, and control is performed so as to switch to slag discharge from the slag lock hopper 10 of the B system after a certain period of time has elapsed. At this time, as shown in FIG. 3, the slag is received in the system A, but since the slag clogging may occur in the upper pipe 3 on the upstream side of the slag lock hopper 9, the control device 37 During the slag receiving operation in the A system, the cooling water supply valve 29 is adjusted to increase the cooling water supply flow rate, and control to eliminate slag clogging is performed.

  Thereafter, the slag discharge from the slag lock hopper is switched from the slag discharge by the B system to the slag discharge by the A system again. Here, if the weight increase rate of the slag bunker 21 is normal, the operation is continued as it is. However, if it is determined that there is an abnormality, the control device 37 switches to slag discharge by the B system. Maintenance is performed. This maintenance location is limited to the slag discharge part of the upper pipe 3 and the slag lock hopper 9 and is performed in a short time. Even if the blockage occurs in the system, the gasifier 1 can be operated continuously without any trouble.

  As described above, according to the slag discharge device of the present embodiment, two slag discharge systems can be alternately switched and operated, so that the slag that has been crushed in the gasifier 1 is continuously discharged. It becomes possible. Thereby, blockage of the slag discharge part in the lower part of the gasification furnace frequently generated in the conventional slag discharge apparatus can be prevented, and the reliability of continuous operation of the gasification furnace can be ensured.

  Moreover, although the example provided with two slag discharge systems was demonstrated in the slag discharge apparatus of this embodiment, even if it has more slag discharge systems, switching control is performed so that slag is discharged continuously. Thus, the same effect as in the present embodiment can be obtained.

DESCRIPTION OF SYMBOLS 1 Gasification furnace 2 Slag crusher 3, 4 Upper piping 5,7 Upper cut valve 6,8 Upper seal valve 9,10 Slag lock hopper 11,12 Cooling water supply valve 13,14 Decompression shutoff valve 15,17 Lower cut valve 16, 18 Lower seal valve 19 Slag separation tank 20 Slag conveyor 21 Slag bunker 22 Load cell 29, 30 Cooling water supply valve 31, 32 Overflow water shutoff valve 34, 35 Slag discharge piping 36 Level meter 37 Control device 61 Storage hopper

Claims (1)

A gasification furnace having a gasification section that gasifies solid fuel and generates molten slag, and a storage hopper that stores cooling water that granulates the molten slag flowing down from the gasification section, and the gasification furnace In the slag discharge device comprising a slag container that communicates with the bottom of the slag and stores and discharges the slag discharged from the storage hopper,
The slag container is connected to the ends of a plurality of piping systems through which the slag discharged from the gasification furnace flows, and switching means for switching the piping systems, and pressure release for releasing the pressure in the slag container Means, and slag discharge means for discharging the slag stored in the slag container,
Control means for controlling operations of the pressure release means, the slag discharge means, and the switching means, a slag bunker for collecting the slag discharged from each slag container, and the weight of the slag collected in the slag bunker. A weight detecting means for detecting the water intermittently or intermittently, and a cooling water supply means for supplying cooling water to the slag container,
When the weight increase rate of the slag by the weight detection means is less than a specified value, the control means supplies cooling water into the slag container that discharges the slag , and a plurality of the connected slag containers are connected after a lapse of a predetermined time. The slag discharge device is characterized in that cooling water is simultaneously supplied to the upper pipe and the piping system is switched and controlled so that the slag crushed by the storage hopper is continuously discharged.

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