JPH11140464A - Coal gasification apparatus and slag discharge by the same apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively solve blockage of a connecting part due to slag while the blockage by the slag is slight by surely detecting the occurrence of blockage of the connecting part due to the slag. SOLUTION: This coal gasification apparatus is obtained by making melt slag 9 produced in a gasification furnace 1 flow into slag cooling water 8 and quenching the melt slag 9 to provide water-granulated slag 10, dropping the slag 10 through a connecting part 37 comprising a connecting tube 37c and a valve 25 into a slag lock hopper 14, temporarily storing the slag 10 in the hopper 14 and discharging the slag 10 out of the system. In this case, a first solving means for rapidly raising gas so as to eliminate the slag 10 when the connecting part 37 is blocked with the slag 10 is additionally installed in the connecting part 37. Then, the first solving means is a gas injecting line 23 containing a valve 27 and provided in either one part of a lower part of the connecting pipe 37c which is located in the vicinity of the upper part of the slag lock hopper 14 or the upper part of the slag lock hopper 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for melting ash in coal to form slag, and discharging the slag to the outside of the system via a lock hopper connected to a gasification furnace. The present invention relates to a coal gasifier for resolving slag clogged at a connection with a hopper and a slag discharge method using the same.

[0002]

2. Description of the Related Art Coal is a useful energy source with abundant reserves, but more than 10% ash (alumina, silica, etc.)
And harmful metals (Cr, Hg, etc.), the treatment method was difficult and the range of application was narrowed. However, in spouted bed coal gasifiers, coal is partially burned under high temperature with an oxidizing agent such as oxygen to produce useful gas, melt ash, and take it out of the system as slag that hardly dissolves harmful components. Can be. For this reason, the field of application has been expanded, and it is particularly promising as a fuel for power plants or as a raw material for industrial plants. A spouted bed gasification method capable of obtaining high gasification efficiency is described in, for example,
No. 176391.

[0003] As described above, in the spouted bed gasifier, the ash in the raw material is discharged as slag. No. -92391, actual opening 61-98840,
These are disclosed in Japanese Unexamined Utility Model Publication Nos. 62-162244 and 3-70256. Further, as a device relating to a slag cooling unit for storing slag dropped from a slag tap, Japanese Utility Model Laid-Open No. 3-123537 discloses a device for crushing falling slag in water. The idea of imparting a stirring flow to water is disclosed in Japanese Patent Application
In 153389, the valve between the gasifier and the slag lock hopper,
A device for disposing a nozzle for injecting gas into a connecting pipe between the gasification furnace and the gasification furnace is disclosed.

[0004] Of the above-mentioned prior art, FIG.
This is a method described in No. 3389, which shows an example of a system diagram around a slag discharge line of a spouted bed gasifier. In this apparatus, pulverized coal is conveyed from a line 3, and a gasifying agent (oxygen-containing gas or the like) is injected into a pressurized gasification furnace 1 having a higher temperature than a burner 2 using a line 4, The partial combustion is performed, and the product gas 32 generated by the partial combustion is obtained. Here, the downstream device configuration and steps are omitted.

On the other hand, as a by-product of the partial combustion, the ash in the coal is melted to form a molten slag 9. The molten slag 9 is caused to flow down along the slag tap discharge hole 5 provided at the bottom of the gasification furnace 1, and is allowed to flow downward into the slag cooling water 8 filled in the cooling unit 7 with a space 11 therebetween. The water is granulated, rapidly cooled to form granulated slag (slag) 10, and then discharged from the slag discharge hole 33 of the cooling unit 7. A slag crusher is installed in the cooling section 7 for the purpose of improving
May be further crushed, but omitted here.

The discharged granulated slag 10 passes through a connecting portion 47 comprising a valve 25 and a connecting pipe 47c disposed below the gasifier 1, and is supplied to the slag lock hopper 14 maintained at substantially the same pressure.
And stored for a certain period of time. This time is called slag precipitation. After a certain period of time, the granulated slag 10 stored in the slag lock hopper 14 closes the valve 25 and opens the valve 26 to bring the inside of the slag lock hopper 14 to atmospheric pressure, then opens the valve 30 and pressurizes from the valve 31. Cooling water 15 is supplied to take out the granulated slag 10 while cutting it out. This time is called slag discharge. The extracted granulated slag 10 is carried by the cooling water 19 via the transport line 20 and the like. When the discharge is completed, the valve 30 is closed, the cooling water 16 is filled with the pressurized cooling water 15 in the slag lock hopper 14, and then the valve 26 is closed to perform pressurization. This time is respectively filled with water and pressurized. When the pressurization is completed, the valve 25 is opened and the gasifier 1 and the slag lock hopper are opened.
Connect to 14 and perform slag precipitation again.

[0007] In the spouted bed gasifier, the properties of the molten slag 9 change due to slightly different conditions such as the quality of the coal and the temperature of the gasification section 6 and the space section 11. The particle size and shape of the granulated slag 10 change, and sometimes a thread-like product is generated. While the slag is falling, it falls from the slag discharge hole 33 provided at the bottom of the gasification furnace 1 to the slag lock hopper 14 through the connecting portion 47. The slag 10 accumulates. During this period, the thread-like material is entangled with each other, or the granular material is compacted to form a bridge, and the connection pipe 47c and the valve 25 are closed, and the slag lock is removed from the gasification furnace 1. The granulated slag 10 may not be able to move to the hopper 14. When the clogging of the granulated slag 10 cannot be eliminated, the granulated slag 10 gradually accumulates in the cooling unit 7 and the molten slag 9 is not granulated and fills the inside of the gasification furnace 1 so that the operation must be stopped. .

In order to solve this problem, in the prior art, a nozzle 43 and a valve 44 for injecting gas into the connecting pipe 47c above the valve 25 are provided to break the bridge by the injected gas and stabilize the slag outside the system. To be discharged to Also,
In this publication and Japanese Patent Application No. 5-160612, a device (such as a microphone) for detecting the sound of moving slag is provided in the connecting pipe 47c.
A method for detecting slag blockage is disclosed. FIG. 8 shows the ejector 17, the differential pressure transmitter 28, and the cooling water supply line.
12 and valves 21, 22, etc. are shown.

[0009]

In a conventional coal gasifier, a large amount of gas is supplied in a short time in order to cut off slag which is closed by injecting gas into an upper connecting pipe. And a more effective implementation required a gas supply at a pressure significantly higher than the operating pressure of the gasifier. In addition, the probability that the slag contacts the pipe wall of the connecting pipe during the falling of the slag is low, and the means for generating the impulsive sound and the fricative sound caused by the slag is not specified, and the detection accuracy of the slag falling state is low. There was a point.

[0010] An object of the present invention is to provide a coal gasifier capable of reliably detecting the occurrence of slag blockage and effectively eliminating the blockage while the slag blockage is slight, and a slag discharge method using the coal gasifier. It is to provide.

[0011]

In order to solve the above-mentioned problems, a coal gasifier according to the present invention has a molten slag generated in a gasifier flowing down into slag cooling water, rapidly cooling the slag, and adding water to the slag. In a coal gasifier that crushes, drops slag via a connecting portion, stores the slag in a slag lock hopper, and then discharges the connecting portion, the connecting portion rapidly increases the gas so as to eliminate the slag when the slag is closed. A configuration is provided in which a canceling means and / or a second canceling means for rapidly lowering the cooling water is provided.

The first solution may be a gas injection line provided near the upper part of the slag lock hopper.

The second solution may be a cooling water extraction line provided near the upper portion of the slag lock hopper.

Further, a means for detecting a slag falling condition is provided, and the means for detecting is a slag contact portion provided at a lower portion of the connecting portion so as to come into contact with the slag falling, and a sound and / or sound caused by the slag contact. Alternatively, a configuration provided with a vibration detector may be employed.

Then, the molten slag produced in the gasification furnace is caused to flow down into slag cooling water to be rapidly cooled and granulated into slag. The slag is dropped through a connecting portion, stored in a slag lock hopper, and then discharged into coal gasification. In the apparatus, a means for detecting a slag drop condition is provided, and the means for detecting is a slag contact portion provided at a lower portion of the connecting portion so as to come into contact with the slag being dropped, and a sound and / or sound caused by the slag contact is provided. A configuration provided with a vibration detector may be used.

The slag contact portion includes at least a detection rod,
The inclined tube or the bent tube formed at the lower part of the connection portion, and the detector may be provided inside or outside the pressure vessel near the slag contact portion.

Further, in the method for discharging slag of a coal gasifier, any one of the above coal gasifiers is used,
The molten slag generated in the gasification furnace is allowed to flow down into the slag cooling water, rapidly cooled and granulated into slag, the slag is dropped through the connection part, stored in the slag lock hopper, and discharged after being discharged from the coal gasifier. In the method, when clogged with slag, the gas is rapidly raised in the connection portion and / or the cooling water is rapidly lowered so as to eliminate the clogging.

According to the present invention, since the gas injection line is provided near the upper part of the slag lock hopper, when the slag blockage occurs at the connection between the gasification furnace and the slag lock hopper, the gas rapidly rises and closes at the connection. Is eliminated. In addition, since the cooling water extraction line is provided near the upper part of the slag lock hopper, the cooling water is rapidly lowered at the connecting portion, and the blockage is eliminated. And, since the slag contact part for detecting the falling slag is formed in the connecting pipe below the valve of the connecting part, and the detector is attached, the falling slag surely hits the slag contact part, and the detection accuracy of the presence or absence of blockage in the connecting part is improved. Be improved.

For this reason, a collision part (inclined part or bend part of a detection rod or a pipe, etc.) is arranged, and the inside of the vicinity of the collision part (in a pressure pipe or pressure vessel) or the outer surface near the collision part (the pressure pipe or A sensor 34 for detecting sound or vibration is provided outside the pressure vessel).

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIG. As shown in FIG. 1, the molten slag 9 generated in the gasification section 6 of the gasification furnace 1 is caused to flow down into slag cooling water 8 in a cooling section 7 to be rapidly cooled, and water is added to a slag (granulated slag) 10. This is a coal gasifier that crushes, drops slag 10 through a connecting portion 37 including a valve 25 and a connecting pipe 37c located below the gasifier 1, temporarily stores the slag 10 in a slag lock hopper 14, and then discharges the slag 10 out of the system. The connecting portion 37 is provided with a first removing means for rapidly rising the gas so as to remove the slag 10 when the slag 10 is closed. The first solving means is a lower part of the connecting pipe 37c near the upper part of the slag lock hopper 14 or a slag lock hopper.
14 is a gas injection line 23 including a valve 27 provided at one of the upper portions.

This embodiment operates as follows. When the slag drop vibration detector 34 detects that the slag blockage has occurred in the connection pipe 37c or the valve 25, the arithmetic unit 35 and the controller 36
By this, a signal for closing the valve (adjustment valve) 25 provided in the connection pipe 37c once and opening the valve (adjustment valve) 27 of the gas injection line 23 is sent, and an arbitrary amount of gas is injected into the slag lock hopper 14. I do. A signal is sent to close the valve 27 and open the valve 25 after the gas injection is completed. As a result, the slag lock hopper 14
The gas stored in the slag rises toward the cooling part 7 of the gasification furnace 1 through the connecting pipe 37c and the valve 25 at a stretch, and forms a bridge above the connecting pipe 37c to close the slag 10 which is closed. The gas passes through the slag cooling water 8 and escapes from the space 11 to the gasifier 6 through the slag cooling water 8. The closed slag 10 starts to fall into the slag lock hopper 14 through the connecting portion 37 after the gas penetrates. As described above, in the present embodiment, since a large amount of gas can be temporarily stored in the slag lock hopper, the gas amount necessary to eliminate the blockage of the slag is also procured from a supply source having a small supply flow rate. be able to.

In the present embodiment, after the gas injection is completed, the valve 31 is opened, and the pressure of the slag lock hopper 14 is increased by the pressurized cooling water 15 to be higher than the operating pressure of the gasification furnace 1. By opening the valve 25, the slag lock hopper
With the expansion of the gas stored in 14, the bridging slag can be crushed, and the clogging can be more effectively eliminated. In such an operation, there is a feature that a gas supply source having a low pressure can be used. In addition, the installation position of the gas injection line 23 is not limited to the slag lock hopper 14, and the gasification furnace 1
Connecting pipe below valve 25 between slag lock hopper 14
The same effect as described above can be obtained with 37c.

According to this embodiment, the molten slag 9 generated by melting and fluidizing ash such as coal burned in the gasification furnace 1 installed in the pressure vessel is supplied to the cooling unit 7 provided at the bottom of the apparatus. The slag is cooled by flowing down into the slag cooling water 8 stored in the slag, and at the same time, is formed into granulated slag 10 and is drawn out of the system through the connecting portion 37 and the slag lock hopper 14. Lower connecting pipe of valve 25 between
37c or gas injection line above slag lock hopper 14
23 are provided. Then, by temporarily storing the gas in the slag lock hopper 14, the valve 25 of the connecting portion 37 is opened, so that a large amount of gas can be injected into the connecting portion 37 at a stretch, and it is also possible to pressurize even a low-pressure gas. As a result, the gas sealed in the slag lock hopper 14 rises to the cooling unit 7, so that the blockage of the bridged slag can be effectively eliminated.

FIG. 2 shows another embodiment of the present invention. The difference between this embodiment and the embodiment shown in FIG. 1 is that a valve 40 is provided in the vicinity of the upper part of the slag lock hopper 14 as a second solution so as to rapidly lower the cooling water to the connecting portion 37. In this configuration, a cooling water extraction line 39 is provided.

The other embodiment operates as follows. Connecting pipe 37 by signal from slag drop vibration detector 34
When it is detected that the slag blockage has occurred in step c, the controller 36
, A signal to gradually open the valve (regulating valve) 22 of the cooling discharge line 13 and gradually open the valve 40 of the cooling water discharge line 39 to increase the pressure in the slag lock hopper 14 The pressure is reduced to the atmospheric pressure, and the moving direction of the cooling water is set downward from the cooling unit 7 toward the connecting unit 37. At this time, since the cooling water discharge line 39 is open to the atmosphere, the pressure of the slag lock hopper 14 decreases, and the pressure of the gasification furnace 1 is gradually applied from above the slag closing portion of the connecting portion 37, and the bridge Is released and the slag 10 falls below the connecting portion 37 toward the slag lock hopper 14, and the slag 10
10 does not block the connection portion 37 again. Since the level of the slag cooling water 8 in the cooling unit 7 decreases with this operation, it is necessary to increase the opening degree of the valve (adjustment valve) 21 and adjust the amount of cooling water injected from the cooling water supply line 12. is necessary. When the slag blockage at the connecting portion 37 is eliminated, the signal from the slag drop vibration detector 34 is continuously detected at a normal level, and the controller 36 firstly outputs the valve 40 of the cooling water extraction line 39.
The opening of the valve 21 is gradually reduced, the opening of the valve 21 is returned to a normal value, and the level of the slag cooling water 8 is controlled by the opening of the valve 21 of the cooling water extraction line 12. The installation position of the cooling water discharge line 39 is not limited to the present embodiment, and the same effect can be obtained by directly installing the cooling water extraction line 39 on the slag lock hopper 14 as long as it is between the valve 30 and the valve 30 from below the valve 25. Can be obtained.

According to the other embodiment, as a second eliminating means for eliminating the bridge of the slug 10 of the connecting portion 37,
A cooling water extraction line 39 and a valve 40 are provided below the connecting pipe 37c or in the slag lock hopper 14. Since the direction of dissolving the bridged slag 10 and the direction of water discharge coincide with each other, the slag that has been once clogged does not block the connecting portion 37 again, so that effective slag discharge can be performed.

FIG. 3 is a system diagram of a gasifier as another embodiment of the present invention. In FIG. 3, a slag contact portion (detecting means) 37a is formed below the connecting pipe 37c of the valve 25 of the connecting portion 37, and a slag drop vibration detector 34 is arranged. The input is connected to an operating device such as a valve 27 of the gas injection line 23 and / or a valve of a cooling water extraction line for eliminating slag blockage. However, the arithmetic unit 35 and the controller 36 are provided when the operation is controlled by amplifying the signal, and the slag drop vibration detector 34 alone can monitor the slag drop condition. Ie slag
A means for detecting the drop situation of 10 is provided, and the means for detecting are:
A slag contact portion 37a formed below the connecting portion 37 so as to come into contact with the falling slag 10, and is provided with a sound and / or vibration detector (slag drop vibration detector) 34 due to slag contact. Configuration.

According to the present embodiment, the impact sound and the friction sound of the slag are surely generated at the connection between the gasifier and the slag lock hopper, and the detection accuracy for detecting the slag falling state is improved.

FIG. 4 shows another embodiment of the present invention.
A detection rod 38 is inserted into the 37c, and a slag drop vibration detector 34 is installed on one end of the detection rod 38 outside the pipe or on the outer surface of the connecting pipe 37 in the vicinity.

The present embodiment having the above configuration operates as follows. The granulated slag 10 sinks in the slag cooling water 8 stored in the cooling unit 7 during the slag sedimentation period, passes through the slag discharge hole 33 through the connecting portion 37, and then enters the slag lock hopper.
Stored at 14. The granulated slag 10 collides with the detecting rod 38 when passing through the connecting pipe 37c, and the sound and / or vibration generated at that time is generated at the end outside the pipe of the detecting rod 38 and the connecting pipe 37c near the end.
To the outer surface of the pipe. The sound and / or vibration is detected as a signal by the slag drop vibration detector 34,
35 and the controller 36. Slug drop vibration detector 34
There are various types that output sound and / or vibration as vibration speed or vibration acceleration, and microphones that detect some sounds have similar functions, and are not limited to vibration detection . When the signal of the slag drop vibration detector 34 is, for example, a vibration acceleration, the arithmetic unit 35 and the controller 36 can externally monitor the signal as sound. Alternatively, the vibration speed signal can be processed and output as a vibration speed which is a time integration value or an amplitude obtained by further time integration. In any case, the same detection as described below can be performed. Here, the case of detecting as vibration acceleration will be described.

FIG. 5 shows a temporal change of the vibration acceleration (unit: G) which is the output signal of the slag drop vibration detector 34. During the slag sedimentation period, a signal of 0.25 to 0.3 G is detected due to the vibration generated when the granulated slag 10 collides with the detection rod 38.
Is closed, the granulated slag 10 stays at the bottom of the gasifier 1, and no signal is detected. Next, after the slag lock hopper 14 is pressurized, the gasifier 1 and the valve 25 are opened to connect the slag lock hopper 14, and when slag blockage occurs at the connection portion 37 when slag precipitation is started, a normal slag dropping is performed as shown in the figure. Is not detected, and a signal for opening the valve 27 is immediately sent from the controller 36 to inject gas from the gas injection line 23, and thereafter, as the slag blockage is resolved, the granulated slag 10 Was dropped at once, and a somewhat large signal of 0.4G was observed for a while, and then 0.25 with stable slag discharge.
It has been confirmed that the G signal is detected.

FIG. 6 shows another embodiment of the present invention. Slug drop vibration detector 34 installed on connecting pipe 37c in FIG.
It is shown enlarged around the periphery. In the present embodiment, a slag contact portion 37a is provided with an inclined portion or bend portion below the connecting pipe 37c, and a slag drop vibration detector 34 is provided on the lower outer surface of the inclined portion. It is desirable that the angle of inclination is not less than the angle of repose of the slag in water with respect to the horizontal line (depending on the particle size of the slag, but about 30 ° for a slag of 1 mm or less) and the angle at which the falling slag contacts the inner surface of the connecting pipe. As a result, a projection such as the detection rod 38 cannot be formed inside the container as in the embodiment shown in FIG.
It is possible to suppress the blockage of the inside of the vessel 10 such as a pipe. In this case, as the granulated slag 10 falls, it always collides with the lower surface of the inclined portion, and then moves to roll on the inner surface.
The detection sensitivity of the signal is improved, and the monitoring accuracy is improved.

FIG. 7 shows another embodiment of the present invention. FIG. 2 is an enlarged view centering around a slag drop vibration detector 34 installed on a connecting pipe 37c in FIG. 1. In the present embodiment, the connecting pipe 37c is provided with an inclined or bent portion, and the slag drop vibration detector 34 is installed on the lower outer surface of the inclined portion. This makes it possible to directly measure the sound and / or vibration in the water, and to improve the detection sensitivity of the slag drop vibration detector 34 without being contaminated by the falling granulated slag.

The embodiment shown in FIG. 2 is an apparatus and a method for effectively eliminating a slag blockage at the connecting portion 37.
Although it is effective to eliminate the slag blockage in the connecting portion 37 by itself, for example, in the embodiment shown in FIG. 1, even when a large amount of slag forms a bridge The bridge can be broken by increasing the injection amount or the pressure, whereas in the embodiment shown in FIG. 2, the bridge in the cooling unit 7 is conversely condensed with the slag. In some cases, the blockage cannot be resolved. In order to block such a relatively large amount of slag that reaches the inside of the cooling unit 7, first, the method shown in FIG. 1 in which the closed slag is blown up and then discharged is applied. By applying the embodiment shown in FIG. 2, slag blockage can be surely eliminated.

Further, in the embodiment shown in FIG.
The slag blockage at 37c can be reliably detected within a small amount. The slag blockage elimination unit (first elimination unit) according to the embodiment shown in FIG. 1 or the slag blockage elimination unit according to the embodiment shown in FIG. By using the slag blockage eliminating means (second eliminating means) in combination or using these three embodiments at the same time, slag occlusion can be effectively and surely eliminated in a small amount.

[0036]

According to the present invention, when the connection between the gasification furnace and the slag lock hopper is closed with slag, the gas is rapidly increased and / or the cooling water is rapidly lowered at the connection by the elimination means. Therefore, the blockage of the slag can be effectively eliminated within a small amount. In addition, the detection means and the like improve the monitoring accuracy of the online slag drop situation, and can immediately detect whether or not the blockage has been cleared to operate each of the clearing means.

[Brief description of the drawings]

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

FIG. 2 is a system diagram of a coal gasifier apparatus showing another embodiment of the present invention.

FIG. 3 is a system diagram of a coal gasification furnace apparatus showing another embodiment of the present invention.

FIG. 4 is a cross-sectional view of a connecting pipe of a coal gasifier, showing another embodiment of the present invention.

FIG. 5 is a graph showing a temporal change of a vibration acceleration which is an output signal of a slag drop vibration detector according to another embodiment of the present invention.

FIG. 6 is a cross-sectional view of a connecting pipe of a coal gasifier, showing another embodiment of the present invention.

FIG. 7 is a cross-sectional view of a connecting pipe of a coal gasifier, showing another embodiment of the present invention.

FIG. 8 is a system diagram of a coal gasifier apparatus showing a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Gasification furnace 6 Gasification part 7 Cooling part 8 Slag cooling water 9 Melting slag 10 Granulated slag 12 Cooling water algae supply line 13 Cooling water extraction line 14 Slag lock hopper 15 Pressurized cooling water 16, 19 Cooling water 17 Ejector 21, 22, 25, 27 valve 23, 43 gas injection line 24 air vent line 28 differential pressure oscillator 30, 31, 40, 44 valve 32 generated gas 33 slag discharge hole 34 slag drop vibration detector 35 computing device 37, 47 connecting portion 37a slag Contact part 37c, 47c Connecting pipe 38 Detection rod 39 Cooling water extraction line

Claims (7)

[Claims] 1. Coal discharged by flowing molten slag generated in a gasification furnace into slag cooling water, rapidly cooling and granulating the slag, dropping the slag through a connecting portion, storing the slag in a slag lock hopper, and discharging. In the gasifier, the connecting portion is provided with first eliminating means for rapidly increasing the gas so as to eliminate the slag when the slag is closed and / or second eliminating means for rapidly lowering the cooling water. A coal gasifier characterized in that: 2. The coal gasifier according to claim 1, wherein the first eliminating means is a gas injection line provided near an upper portion of the slag lock hopper. 3. The coal gasifier according to claim 1, wherein the second eliminating means is a cooling water extraction line provided near an upper portion of the slag lock hopper. 4. The coal gasifier according to claim 1, further comprising means for detecting a slag falling state,
The means for detecting is a slag contact portion provided at a lower portion of the connecting portion so as to contact the slag falling, and it is provided with a detector of sound and / or vibration caused by the contact of the slag. Characterized coal gasifier. 5. Coal discharged by flowing molten slag generated in a gasification furnace into slag cooling water, rapidly cooling and granulating the slag, dropping the slag through a connecting portion, storing the slag in a slag lock hopper, and discharging. In the gasifier, a means for detecting a falling state of the slag is provided, and the detecting means is a slag contact portion provided at a lower portion of the connecting portion so as to come into contact with the slag falling, and A coal gasifier comprising a detector for sound and / or vibration caused by contact. 6. The coal gasifier according to claim 4, wherein the slag contact portion is at least a detection rod, an inclined tube or a bent tube formed at a lower portion of the connection portion, and the detector is:
A coal gasifier is provided inside or outside a pressure vessel near the slag contact portion. 7. Using the coal gasifier according to any one of claims 1 to 6, the molten slag generated in the gasification furnace is caused to flow down into slag cooling water, rapidly cooled, and granulated into slag. In a slag discharging method of a coal gasifier that drops the slag through a connecting portion, stores the slag in a slag lock hopper, and discharges the slag, when the slag is blocked by the slag, gas is supplied to the connecting portion so as to eliminate the blockage. A method for discharging slag from a coal gasifier, wherein the slag is rapidly raised and / or the cooling water is rapidly lowered.