JPH0711262A - Pulverized coal gasifier - Google Patents

Abstract

PURPOSE:To obtain a pulverized coal gasifier capable of stably and surely discharging a slag from the gasifier under pressure to the outside of the system. CONSTITUTION:A nozzle 29 capable of filling a purging gas 31 containing oxygen for destroying bridges formed from a slag 16 is arranged in a connecting pipe 39 between a slag cooling part 3 and a slag locking hopper 17 and a sensor 32 for sensing the movement of the slag is further installed to provide a controller 35 for carrying out the control over the discharge of the slag to the outside of the system. Thereby, the slag can stably and surely be discharged to the outside of the system.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an air-bed type gasification furnace for converting a combustible content of a fine powdered solid carbonaceous raw material typified by coal into a produced gas and discharging ash as slag in a gasification furnace. The present invention relates to a device for stably discharging slag out of the system.

[0002]

2. Description of the Related Art Conventionally, various systems such as a fixed bed, a fluidized bed, and a gas bed have been proposed as a furnace system for gasifying a solid carbonaceous raw material such as coal. Among these methods, the airflow layer method is a method in which the raw material is made into fine powder and is supplied together with an oxidizing agent such as oxygen or air into a furnace at a temperature (1300 to 1600 ° C) higher than the melting point of the raw ash to combust the raw material. This is a method of converting the amount of gas into gas and the amount of ash into slag. Therefore, the airflow layer method has characteristics such as high gasification efficiency, a wide range of applicable coal types, and excellent environmental compatibility as compared with other methods. Therefore, the gas taken out from this system is
Since it is suitable for producing fuels such as fuel cells and raw materials such as synthesis gas, it is being developed domestically or overseas. Incidentally, a gas stream gasification method capable of obtaining high gasification efficiency is disclosed in, for example, JP-A-59-176391.

As described above, in the gas stream gasification furnace, the ash content in the raw material is discharged as slag, but as a method for stably flowing down the slag from the slag tap in the lower part of the gasification furnace, it is disclosed in Japanese Patent Laid-Open No. No. 60-92391, No. 61-98840,
It is disclosed in Japanese Utility Model Publication No. 62-162244 and Japanese Utility Model Publication No. 3-70256. Furthermore, as a device for the slag cooling section that collects the slag that has flowed down from the slag tap, the
In the 23537 publication, the idea of crushing the falling slag in water is proposed.
Further, in Japanese Utility Model Laid-Open No. 1-161241, in order to discharge the slag that has been water granulated in the slag cooling section, a stirring flow is applied to the cooling water injected into the slag cooling section, or from the slag cooling section to the slag lock hopper. It is described that the cooling water flow is changed so that the slag flows down when the slag is discharged.

[0004]

A slag cooling section in which water is stored is arranged below the pressurized gasification furnace, and the slag flowing down from the slag tap in the cooling section has a particle size of several due to thermal stress. Granulated to mm. A valve is arranged between the cooling unit and the slag lock hopper. The valve usually has an inner diameter of about 200 mm. Therefore,
The diameter of the slag cooling section is conically reduced toward the bottom of the furnace. Between the valve and the slag cooling section, and between the valve and the slag lock hopper, connecting pipes having the same inner diameter as the valve are arranged.

The case of the above-mentioned publication is a device for removing a bridge in which the slag is formed in a compacted state in the conical portion of the slag cooling portion. However, according to the experiments by the present inventors, the portion where the slag is compacted and the bridge is formed is the portion of the connecting pipe having the smallest diameter, and the blockage occurs at this portion. If the slag bridge is clogged in the connecting pipe, no matter how much the conical portion of the slag cooling portion is agitated, there is no effect in removing the bridge formed in the connecting pipe. Furthermore, it was confirmed that if the slag of the connecting pipe could be discharged, the slag accumulated in the cooling part could also be discharged stably, and if the connecting part was subjected to vibration, the slag would be extremely consolidated.

By the method described in Japanese Utility Model Laid-Open No. 1-161241, it is possible to prevent the slag from falling into the connecting pipe except when discharging the slag, but in that case, a large amount of cooling water is supplied. This is not practical because it requires a large-diameter supply pipe and a large-capacity supply pump. When the slag in the slag cooling unit cannot be discharged, the slag falling from the slag tap is accumulated above the cooling water surface, the slag is no longer cooled in the slag cooling unit, and the slag forms a large bridge, which may damage the gasifier. In some cases, it may not be possible to restart the function of the gasifier.

An object of the present invention is to provide a pulverized coal gasifier which can stably and reliably discharge slag from the gasifier under pressure to the outside of the system.

[0008]

[Means for Solving the Problems] The above-mentioned problems are as follows:
Further, in a pressurized furnace, a gasification section for converting a combustible content of the raw material into a produced gas composed of carbon monoxide and hydrogen and an ash content of the raw material into slag by using an oxidizing agent, and the gasification section. And a slag cooling section that is arranged above the gasification section, where a heat recovery section that recovers heat from the generated gas is collected, and cooling water that hydrolyzes the slag that flows down is stored. A pulverized coal gasifier comprising a gasification furnace including the slag lock hopper connected to the gasification furnace via a valve below the gasification furnace, wherein the gasification furnace and the slag lock are provided. This is achieved by arranging a nozzle for injecting gas at the connection part with the hopper.

[0009]

When the slag does not move from the slag cooling part to the slag lock hopper, if gas is injected into the connection part between the slag cooling part and the slag lock hopper, the slag accumulated at the connection part or the bottom of the slag cooling part Through which the gas passes. Therefore, even if the bridge is formed by the slag at the connection part or the bottom of the slag cooling part, the bridge is destroyed by the injected gas, and the slag is stably discharged out of the system.

[0010]

FIG. 1 shows an embodiment of the present invention. The gasification furnace main body 1 converts a combustible content in coal into a gas composed of hydrogen and carbon monoxide, and a gasification section 2 for converting ash content in coal into a slag 16, and below the gasification section 2. It includes a slag cooling unit 3 that is disposed and stores the cooling water 8 and a heat recovery unit 4 that is disposed above the gasification unit 2 and that recovers heat from the generated gas generated in the gasification furnace 1. It is composed of.

The gasification section 2 is arranged so as to penetrate through the furnace wall 40, one end of which is opened into the furnace, and the other end of which is the raw material supply line 1.
1 and 12 and burners 9 and 10 connected to the oxidant supply lines 13 and 14, and a slag tap 15 for dropping the slag 16 into the slag cooling unit 3. The heat recovery unit 4 includes a generated gas line 36 for extracting the gas generated in the gasification unit 2 from the gasification furnace 1, a boiler water supply line 5 for a heat recovery boiler for recovering heat of the generated gas, and a boiler water. It consists of an exit line 6. A slag lock hopper 17, which is connected to the slag cooling unit 3 via a connecting pipe 39 via a valve 18, is arranged below the gasification furnace main body 1, and the slag lock hopper 17 is connected via a valve 38 to the high pressure water 20. High pressure water injection line for injecting water and high pressure water 2 via valve 37
A high-pressure water discharge line for overflowing 1 is provided. Further, high pressure water 23 is used to eject the ejector 22 through a valve 19 arranged below the slag lock hopper 17.
Is operated to take out slag and water from the slag lock hopper 17, and a slag transport line 24 for transporting the slag 28 with water is arranged. Solid-liquid separation for separating the slag 16 transported by the slag transport line 24 from water. Device 25,
A slag hopper 27 is provided for charging the separated slag 28 using a belt conveyor 26.

A nozzle 29 for injecting a gas 31 is arranged in a connecting pipe 39 between the slag cooling part 3 and the valve 18,
A slag movement detector 32 for detecting slag moving from the cooling unit 3 to the slag lock hopper 17 is arranged in a connecting pipe 39 between the valve 18 and the slag lock hopper 17. The control circuit of the control valve 30 uses the slag movement detector 3
The signal line 34 for sending the signal No. 2 to the controller 35 and the signal line 33 for transmitting the signal for the controller 35 to receive the signal and operate the control valve 30. The slug movement detector may be, for example, a device such as a phototube that receives light to generate power when the slug moves, or a device that senses sound emitted when the slug moves along the connecting pipe, such as a microphone. .

When the molten slag 16 of 1300 to 1600 ° C. generated in the gasification section 2 falls into the cooling water 8 of the slag cooling section 3, there is a temperature difference of several hundred degrees between the surface and the inside of the slag 16. Due to the generated thermal stress, the particle size of the slag 28 is water granulated to several millimeters and is temporarily stored in the cooling water 8 of the slag cooling unit 3.

The inside of the slag lock hopper 17 is filled with high-pressure water 20, and the pressure of the slag lock hopper 17 is changed to the gasification section 2
After increasing the pressure to the same pressure as the above, the valves 37 and 38 are closed to stop the flow of the high-pressure cooling water 20, the valve 18 is opened, and the slag 28 accumulated at the bottom of the cooling unit 3 is slagged from the slag cooling unit 3. The valve 18 is moved to the lock hopper 17 and the valve 18 is closed after a certain period of time. After that, the valve 19 below the slag lock hopper 17 is opened, the ejector 22 is operated by the high pressure water 23, the mixture of slag and water in the slag lock hopper 17 is taken out, and the solid-liquid separation device is used using the slag transport line 24. Transport to 25.

When the valve 18 is opened and the slag 28 is moved from the slag cooling section 3 to the slag lock hopper 17, the slug movement detector 32 continuously detects whether the slag 28 is moving in the connecting pipe 39, If the slag does not move, the control valve 30 is opened and the gas 31 is supplied to the nozzle 29.
To the connecting pipe 39. If the slag forms a bridge at the bottom of the slag cooling unit 3 and if gas 31 is continuously injected from the nozzle 29, the gas 31 passes through the slag accumulated in the slag cooling unit 3, so that the bridge is It can be broken and move the slag stably.

As the gas 31, the gas generated from the gasification furnace 1 may be recycled and used. In this case, the calorific value of the generated gas does not change. If the slag 28 cannot be stably extracted from the slag cooling unit 3, it is abnormal and the gas must be frequently injected. However, if gas is injected frequently, the temperature of the slag cooling section is lowered by this gas. Slag tap 1 when the temperature is lowered
5 is blocked by the slag 16 and adversely affects the function of the gasification section 2. Therefore, the gas to be injected should contain oxygen. If the oxygen-containing gas is injected in this way, the gas reacts with the combustible gas in the slag cooling section 3 and rather the temperature of the slag cooling section rises. Therefore, the slag tap is not blocked by the low temperature.

[0017]

According to the present invention, slag can be stably and reliably discharged out of the system from the gasification furnace under pressure.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a pulverized coal gasifier according to an embodiment of the present invention.

[Explanation of symbols]

1 Gasification furnace main body 2 Gasification part 3 Slag cooling part 4 Heat recovery part 5 Boiler water supply line 6 Boiler water outlet line 7 High pressure cooling water 8 Slag cooling water 9 Burner 10 Burner 11 Raw material line 12 Raw material line 13 Oxidizer line 14 Oxidizer line 15 Slag tap 16 Slag 17 Slag lock hopper 18 Valve 19 Valve 20 High pressure water 21 High pressure water 22 Ejector 23 High pressure water 24 Slag transfer line 25 Solid-liquid separation device 26 Belt conveyor 27 Slag hopper 28 Slag (water granulated) 29 Nozzle 30 Control valve 31 Gas 32 Slag movement detector 33 Signal line 34 Signal line 35 Controller 36 Generated gas line 37 Valve 38 Valve 39 Connecting pipe 40 Furnace wall

Front Page Continuation (72) Inventor Shinji Tanaka 7-1 Omika-cho, Hitachi City, Ibaraki Hitachi Ltd. Hitachi Research Laboratory (72) Inventor Ryoichi Hashimoto 3-1 Nakasode, Sodegaura-shi, Chiba Coal Utilized hydrogen manufacturing technology research association in driving laboratory

Claims (3)

[Claims] 1. The temperature inside the furnace is maintained at least at the melting temperature of the ash of the fine powder solid raw material, and the combustible content of the raw material is enriched with carbon monoxide and hydrogen by using an oxidizer in the pressurized furnace. In the generated gas, a gasification part for converting the ash content of the raw material into slag, a heat recovery part arranged above the gasification part for recovering heat from the generated gas, and the slag flowing down into water Was connected to the gasification furnace via a valve below the gasification furnace, including a slag cooling section in which cooling water to be crushed is stored and arranged below the gasification section. A pulverized coal gasifier comprising a slag lock hopper and a pulverized coal gasifier, wherein a nozzle for injecting gas is arranged at a connecting portion between the gasification furnace and the slag lock hopper. 2. The pulverized coal gasifier according to claim 1, wherein the gas injected into the connection portion between the gasification furnace and the slag lock hopper is an oxygen-containing gas. 3. A detector for detecting a moving state of slag falling from the gasification furnace to the slag lock hopper is arranged at a connecting portion between the gasification furnace and the slag lock hopper, and the detector is The pulverized coal gasifier according to claim 1, wherein the injection amount of the gas is controlled by a detection signal.