JP3395010B2 - Gas bed gasifier - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluidized bed gasification plant, and more particularly to a fluidized bed gasification apparatus in which sulfide corrosion due to sulfide contained in a raw material is remarkably reduced.

[0002]

2. Description of the Related Art Conventionally, various systems such as a fixed bed, a fluidized bed and a gas stream bed have been proposed for a furnace for gasifying a solid carbonaceous raw material such as coal. Among these methods, the airflow layer method is for finely powdering the raw material and supplying it to a furnace at a temperature (about 1300 to 1600 ° C.) above the melting point of the raw material ash together with an oxidizing agent such as oxygen or air for gasification, Compared to other methods, it has characteristics such as high gasification efficiency, wide range of applicable coal types, and low pollution by-products, making it suitable for fuel production such as syngas, combined cycle power generation and fuel cells. Therefore, development is underway both in Japan and overseas.

A conventional technique of a gas stream gasifier will be described with reference to FIG. The structure of this device is as follows:
An unburned-content recovery device such as a cyclone 30 for recovering unburned-content and a heat recovery boiler 40 are installed downstream thereof, and a gas purification device such as a desulfurization device 50 is installed further downstream thereof. These devices are gas lines 31, 32,
They are connected by 42.

In the gasification furnace, the raw coal 23 and the oxidizer 22 are burned by the burner 21, and the furnace wall is made of the refractory material 12 and the water cooling wall 11.
Is gasified in a furnace surrounded by, and the gas is gas line 31
Guided to the cyclone 30. On the other hand, the incombustible content of the raw material is melted in the furnace, flows down from the slag hole 17 in the lower part of the furnace into the cooling water 18, and precipitates. The precipitate (slag 20) is discharged outside the furnace by opening the valve 19. During operation, the inside of the gasification furnace is at a temperature higher than the melting temperature of the raw ash as described above, so in order to protect the gasification furnace, furnace wall cooling means is provided on the furnace wall 11 of the gasification furnace,
This recovers the heat in the furnace. That is, the water in the drum 60 is injected from the lower header 13 of the furnace wall cooling means using the pump 64 and the water absorption lines 61 and 62, and the steam that has recovered the heat in the furnace is the upper header 2 of the furnace wall cooling means.
4 is returned to the drum 60 via the steam line 63.

As the desulfurization apparatus 50, a wet method in which an amine-based absorbent 52 is supplied and circulated in the packed tower 51 by absorbent lines 53 and 54 and a pump 55 is currently used. In this method, a heat recovery boiler 40 is installed upstream of the desulfurization device 50 in order to efficiently recover the heat generated in the gasification furnace. In the heat recovery boiler, the heat transfer pipe 41 is provided inside, and the water in the drum 70 is guided to the heat transfer pipe 41 by the water absorption lines 71 and 72 and the pump 74 to recover the heat of the gas and become the steam, and the steam line 73. It is adapted to be returned to the drum 70 via. In addition, since the capacity of the heat recovery boiler 40 is high enough to cool the generated high temperature gas (about 1000 ° C.) to about 400 ° C. during gasification operation, the temperature of the generated gas is lower, the condensed water vapor contained in the gas, the sulfur component contained in the raw material melts by acid occurs in the condensed water, corrosive gas line 4 2 occurs by the acid. Therefore, a burner 14 is provided in the lower part of the gasification furnace 10, and at the time of start-up, the combustion gas generated by burning the light oil or the heavy oil 15 in the burner 14 is caused to flow in the gas line to dew the gas line or the like. Above temperature (about 150
℃).

[0006]

In the prior art, before starting the gasification furnace, the combustion gas generated by burning the light oil or the heavy oil by the starting burner 14 provided in the lower part of the gasification furnace 10 is used. By flowing through the piping of the heat recovery boiler 40 and the piping after the boiler, the temperature of the piping is raised to a temperature above the dew point of steam (150 ° C.), and sulfide corrosion caused by sulfide contained in the solid fine powder raw material is suppressed. ing. However, the capacity of the heat recovery boiler 40 installed downstream of the gasification furnace 10 is very high, and moreover, the amount of combustion gas generated at start-up is much larger than the amount of gas generated during gasification operation. Since the number of combustion gases is small, the temperature of the combustion gas at the time of start-up is significantly reduced when passing through the heat recovery boiler 40. Therefore, the conventional gas stream gasification furnace has a drawback that it takes a long time of 2 to 3 days to heat the piping of the heat recovery boiler and the piping after the heat recovery boiler at the time of starting the gasification furnace. there were. In particular, in the integrated coal gasification combined cycle system, which requires frequent load changes or frequent start / stop, reduction of the start time has been an issue.

The gas stream gasification furnace is generally housed in a pressure vessel of several tens of atmospheric pressure, and the burner tip is directed to the slag hole in order to raise the temperature to a temperature higher than the melting temperature of coal ash. Light oil or heavy oil is used as the fuel for the starting burner, and nitrogen-containing gas with high oxygen concentration is used as the oxidizer. When these are burned at the time of start-up, they are high temperature and pressurized combustion, so even if diesel oil has no nitrogen in the fuel,
So-called thermal NOx is generated in large quantities on the order of several PPM, and this becomes nitrous oxide. This gas becomes nitric acid, which is highly corrosive when dissolved in water, so it is necessary to rapidly raise the temperature of the pipe to a temperature at which water does not condense even at the time of startup.

The object of the present invention is to produce gas produced in a gasifier.
And a downstream of this heat recovery means
In order to suppress sulfide corrosion by heating the gas line of
An object of the present invention is to provide a gas stream gasification apparatus capable of

[0009]

In order to achieve the above object, the present invention provides a gasification furnace which is supplied with a solid fine powder raw material and an oxidizing agent and converts them into a gas rich in carbon monoxide and hydrogen, and this gas. It includes a starting burner and the furnace wall cooling means provided in the furnace, and a heat recovery unit for recovering heat from the gas generated in the gasification furnace provided downstream of the gasification furnace, before
The furnace wall cooling means and the heat recovery system of the heat recovery means are thermally
In the independently formed gas stream gasifier, the furnace wall
The recovered heat of the gasification furnace is recovered by the cooling means, it is characterized in that the recovered heat introducing means for introducing into the heat recovery means is provided. Alternatively, for furnace wall cooling means
The recovered heat that is recovered is conducted to the heat recovery means only at startup.
It may be put in and may be recovered by means of furnace wall cooling.
The recovered heat that is recovered is introduced into the heat recovery means at startup.
A switching means (recovery heat introduction means) may be provided.

In the gas stream gasifier, it is preferable to provide a gas line that bypasses the heat recovery means through which the gas generated in the gasification furnace flows . Also, heat recovery means
Is a heat recovery boiler, the temperature detection means for detecting the temperature in the gas line downstream of the heat recovery boiler, and the temperature value detected by the temperature detection means is introduced into the heat recovery boiler by the recovery heat introduction means. A device provided with a control means for controlling the amount of heat (the amount of steam) is preferable. Also, the amount of heat introduced into the heat recovery steam generator further temperature detecting means for detecting the temperature of the exit portion of the water and steam lines in the heat recovery boiler, by the recovered heat introduction means by the temperature value detected by the temperature detecting means ( A control means for controlling the amount of steam) is preferably provided.

[0011]

According to the present invention , the gasification furnace is used as it is when starting up.
Even when the amount of gas produced is small , the heat recovered by the furnace wall cooling means can accelerate the heating of the heat recovery means.
Collecting means and the temperature of the wake equipment or the dew point of the product gas easily and (about 0.99 ° C.) that-out <br/> in that increasing the temperature in a short time.

Further, if the bypass of the heat recovery boiler is used, gasification can be started without waiting for the temperature increase of the heat recovery boiler whose temperature rises slowly.

Further, means for detecting the temperature is installed in a portion of the gas line after the heat recovery boiler where water in the produced gas may condense, and the recovered heat introducing means is used to detect the temperature depending on the temperature value detected by the temperature detecting means. If the amount of heat (steam amount) introduced into the heat recovery boiler is controlled, the gasifier can be operated easily. Also, the amount of heat introduced into the heat recovery steam generator further temperature detecting means for detecting the temperature of the exit portion of the water and steam lines in the heat recovery boiler, by the recovered heat introduction means by the temperature value detected by the temperature detecting means ( If the steam amount is controlled, the operation efficiency of the gasifier will be improved. As described above, the warm-up operation of the gasifier at startup can be shortened.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic configuration diagram of an embodiment of a gas stream gasification apparatus according to the present invention. In contrast to the conventional schematic configuration diagram shown in FIG. 3, in the present invention, the steam 65 recovered by the furnace wall cooling means provided in the gasification furnace 10 is transferred through the water absorption line 72 to the heat transfer tube in the heat recovery boiler 40. Line 81 supplied to 41
(Recovery heat introduction means) is added. A valve 80 that opens and closes in response to a control signal 92 from a controller 96 is provided on the line 81. The steam or condensate radiated by the heat recovery boiler 40 and cooled is returned to the steam line 73.
May be returned to the drum 70 via a steam line 73
The valve 84 may be closed and returned to the drum 60 via the line 83 connecting the line 73 and the line 63. At this time, the valve 82 of the line 83 is open.

If the condensate is returned to the drum 60 by using the line 83 when the heat recovery amount in the gasification furnace 10 is large, there is an advantage that the level change of the can water in the drum 60 becomes small and the amount of makeup water becomes small. On the contrary, if the condensed water is returned to the drum 60 by using the line 83 when the heat recovery amount in the gasification furnace 10 is small, the steam generation amount in the drum 60 becomes small. At that time, the valve 82 is closed and the valve 84 is opened. Open the drum 7 for condensate from the heat recovery boiler 40
It is better to return it to 0. The valve 85 provided in the line 71 is opened in the normal operation state.

[0016] Thus at startup, since the heat recovered in the gasification furnace so as to introduce the heat recovery boiler, the heat transfer tube 4
1 and the line 42 can be rapidly heated. Therefore, the start-up time of the gasification furnace can be greatly shortened, and the sulfidation corrosion of the pipe can be reduced.

Further, in the gas stream gasification apparatus according to the present invention shown in FIG. 1, a thermometer 90 is installed downstream of the heat recovery boiler 40 and in a line 42 before the wet desulfurization apparatus 50. The temperature detected by the thermometer is sent to the controller 96 by the detection signal 91, and if the detected temperature is lower than the set value, the steam recovered in the gasification furnace 10 is fed to the water absorption line 72 of the heat recovery boiler 40. The valves 80 and 82 are opened and the lines 81 and 83 are used for supply. Reference numerals 93, 94 and 95 respectively represent control signals.
By assembling such a control system, temperature control at startup can be easily performed.

FIG. 2 is a schematic configuration diagram of another embodiment of the gas stream gasification apparatus according to the present invention. In this embodiment, in addition to the line 81 of FIG. 1, a bypass line 100 that bypasses the heat recovery boiler 40 is provided in the gas lines 32 and 42. The bypass line 100 has a control damper 1 which is opened / closed by a control signal 104 from a controller 96.
01 is provided. In addition, in the line 32, the controller 9 is provided on the downstream side of the connecting portion with the bypass line 100.
Control damper 10 that opens and closes according to control signal 103 from 6
Two are provided. A thermometer 97 is provided in the steam line 73 near the outlet of the heat transfer tube 41 of the heat recovery boiler 40.

Next, the operation will be described. When the gasification furnace 10 is started up, first, the start-up burner 14 is burned, and the combustion gas is flowed downstream through the lines 31 and 32. At the same then introduced into water line 7 2 vapor including heat recovered in the gasification furnace 10 at the same time through the line 81, although warm air heat recovery boiler 40 flowing through the heat exchanger tube 41, the heat recovery boiler 40 as described above Since the heat transfer area is large, it takes a long time to raise the temperature. Therefore, the control damper 103 is closed and the control damper 101 is opened by the control signal 103 of the controller 96, and the combustion gas passes through the bypass line 100 without passing through the heat recovery boiler 40. As a result, the downstream line 4
2, 56 and the like are preferentially warmed up in a short time by the combustion gas, and the heat recovery boiler 40 is independently warmed up by the heat recovered in the gasification furnace 10. And the thermometer 97
When the temperature detected by is higher than the set value,
The control damper 103 is opened by the control signals 103 and 104 from the controller 96, while the control damper 101 is closed to switch the combustion gas so as to flow in the heat recovery boiler 40. According to this embodiment, the starting time can be further shortened and the sulfidation corrosion of the pipe can be prevented as compared with the case shown in the above embodiments. According to the embodiment described above
For example, when starting the gasification furnace, the furnace wall cooling provided in the gasification furnace is cooled.
The heat (steam) recovered by the cooling means is supplied to the heat recovery boiler.
Therefore, the heat recovery boiler and the wake of the heat recovery boiler are
The temperature of the pipe is short above the dew point of the produced gas (about 150 ° C).
The temperature is raised between. Therefore, the gasifier can be started in a short time.
In addition, the sulfidation corrosion of the pipe can be suppressed. Change
If you use the bypass line of the heat recovery boiler,
The temperature of the heat recovery boiler, whose temperature rises slowly, can be controlled without waiting for the temperature rise.
You can start converting. In addition, after the heat recovery boiler
Possibility of condensation of water in product gas in gas line
Install a means to detect the temperature in the part where
Depending on the temperature value detected by the output means, by the recovery heat introduction means
If the heat quantity (steam quantity) introduced into the heat recovery boiler is controlled,
The operation of the sooting device becomes easy. Furthermore, a heat recovery boiler
Temperature detection to detect the temperature of water and steam line outlets
Depending on the output means and the temperature value detected by the temperature detection means
Introduced into the heat recovery boiler by the recovery heat introduction means
If the heat quantity (steam quantity) is controlled, the operation efficiency of the gasifier will be
Get better.

According to the present invention, when starting the gasification furnace,
Heat (steam) recovered by the furnace wall cooling means installed in the sootification furnace
Heat is supplied to the heat recovery means (boiler) to be dissipated,
The recovery means and the piping downstream of this heat recovery means are
Is heated to a temperature above the dew point of (about 150 ° C) in a short time,
Sulfide corrosion of piping can also be suppressed .

[0021]

[0022]

[0023]

[Brief description of drawings]

FIG. 1 shows a schematic configuration diagram of a gasifier of the present invention.

FIG. 2 shows a schematic configuration diagram of a gasifier of another embodiment of the present invention.

FIG. 3 shows a schematic configuration diagram of a conventional gasifier.

[Explanation of symbols]

10 gasification furnace 11 water cooling wall 14 Start-up burner 22 Oxidizing agent 23 Solid powder raw material 31, 32 gas line 40 heat recovery boiler 41 heat transfer tube 42 gas line 50 Desulfurization equipment (absorption tower) 56 gas line 60 drums 61, 62 Water absorption line 63 steam line 65 steam 70 drums 72 Water absorption line 73 Steam line 81,83 Steam line 90 thermometer 96 controller 97 thermometer 100 bypass line 101, 102 control damper

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-61-207493 (JP, A) JP-A-61-233083 (JP, A) JP-A-2-195102 (JP, A) JP-A-3- 74492 (JP, A) JP-A-4-20591 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C10J 3/56 C10J 3/86

Claims (5)

(57) [Claims] 1. A gasification furnace for supplying a solid fine powder raw material and an oxidizer to convert them into a gas rich in carbon monoxide and hydrogen, a starter burner and a furnace wall cooling means provided in the gasification furnace. When, in the stream-bed gasification apparatus having a heat recovery unit for recovering heat from the gas generated in the gasification furnace is provided downstream of the gasification furnace, than the heat recovery means
If the temperature detected in the downstream gas line is lower than the set temperature
And a recovery heat introducing means for introducing the recovery heat of the gasification furnace recovered by the furnace wall cooling means into the heat recovery means. 2. The gas stream gasifier of claim 1, wherein:
The recovered heat introduction means, the furnace wall airflow layer gasifier, wherein the Turkey be introduced into the heat recovery unit only recovered heat of the gasification furnace is recovered at startup by the cooling means. 3. The gas stream gasifier of claim 1 , wherein
Stream layer gasifier, wherein a gas produced in the gasification furnace to bypass the heat recovery means passing streamed Ruga Surain is provided. 4. The gas stream gasification apparatus according to claim 1 ,
Temperature detection means for detecting the temperature in the gas line downstream of the heat recovery means, and control means for controlling the amount of heat introduced into the heat recovery means by the recovered heat introduction means according to the temperature value detected by the temperature detection means. An air flow bed gasification apparatus, characterized in that and are provided. 5. The gas stream gasification apparatus according to claim 1 ,
The heat recovery means is a heat recovery boiler, the temperature detection means for detecting the temperature of the water and steam line outlet of the heat recovery boiler, and the recovery heat introduction means by the temperature value detected by the temperature detection means A gas stream gasification apparatus comprising: a control means for controlling the amount of heat introduced into the heat recovery boiler.