JP2002249785A - Coal-gasification apparatus and method for starting the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To economically carry out heating of a char filter which is a char- capturing means at the starting time of a coal-gasification apparatus. SOLUTION: A heat-exchanger 22 for heating nitrogen taken out from an air-separating installation 1 by a piping 35 and pressurized by a blower 39, by steam 21 is installed, and the nitrogen-outlet side of the heat-exchanger is connected to the gas-inlet side of the char filter 13 by a piping 34 having a valve 19 inserted therein in the coal-gasification apparatus having the air- separating installation for separating the nitrogen from air 2 and feeding the separated nitrogen for the transportation of a gasification feedstock, and the char filter 13 for capturing the char from the generated gas.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coal gasification apparatus having an air separation facility for separating nitrogen from air and supplying the separated nitrogen for conveying a gasification raw material.

[0002]

2. Description of the Related Art FIG. 2 shows an example of a system diagram of a conventionally known coal gasifier. The illustrated coal gasifier includes an air separation unit 1 that separates nitrogen from air and uses the separated nitrogen to convey gasification raw materials. At the same time, the separated oxygen is used as an oxidizing agent in a gasification reaction. ing. In addition, a dust collector is provided, which is provided with a heat recovery boiler for recovering heat from the generated gas, and is also a char collecting means (hereinafter referred to as a char filter) for collecting char from the gas after heat recovery.

Conventionally, when starting a coal gasifier,
Before charging the coal 8 into the gasification furnace 10, the light oil 18 and the like are burned by the starting burner 23 provided in the gasification furnace 10, and the gasification furnace 10, the heat recovery boiler 12, and the piping are heated by the high temperature exhaust gas. However, when coal is charged, the moisture of the generated gas containing char in the initial stage of the generation is prevented from being condensed.
The air separation equipment 1 is for separating and generating, from air, nitrogen for transport of raw coal, oxygen for combustion to be supplied to the starting burner 23, and oxygen to be supplied to a gasification furnace as an oxidizing agent during gasification.

However, the introduction of the combustion exhaust gas into the char filter 13 at the time of startup means that the char adhering to the char filter 13 is burned by the oxygen contained in the combustion exhaust gas, and the char adhering in the early stage of the temperature rise. There is a risk that the char may cause filter clogging due to moisture condensation of the combustion exhaust gas. To prevent this, at startup,
It is necessary to close the switching valves 15 and 16 and open the switching valves 14 and 17 so that the flue gas can bypass the char filter 13. The char filter is separately heated by indirect heating with steam or the like, and coal is input. It is to be prepared for ventilation of generated gas at the time.

[0005]

However, in this method, the heating at the time of raising the temperature of the char filter is indirect heating by steam tracing or the like, so that the heating efficiency is poor and a large amount of steam needs to be used. was there.

[0006] It is an object of the present invention to provide more economical heating of a char filter at the time of starting a coal gasifier.

[0007]

SUMMARY OF THE INVENTION The object of the present invention is to heat nitrogen generated in an air separation facility by a heating nitrogen heating means, and to transfer the nitrogen heated by the heating nitrogen heating means to a char filter as a char collecting means. This can be achieved by performing heating at the time of starting the char filter by direct introduction.

Since nitrogen does not contain water, there is no water condensation due to gas passing through the char filter. Also,
Since heating is performed directly with nitrogen, the heating efficiency is greatly improved as compared with indirect heating.

[0009] The heating temperature is equal to or higher than the dew point of the generated gas when the coal is charged into the gasification furnace. The dew point of the generated gas depends on the type of coal,
Although it depends on the properties, it is heated to at least 100 ° C. or more. The upper limit is set to 500 ° C. or less due to restrictions on the material of the char filter.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a system diagram showing a main configuration of a coal gasifier according to an embodiment of the present invention. The illustrated coal gasifier is connected to an air separator 1 that separates and generates nitrogen and oxygen from air, with a pipe 35 having a blower 39 interposed in the air separator 1 and a pipe 36 having a blower 40 and a valve 37 interposed in the air separator 1. Gasifier 1 provided with activated burner 23
0, pulverized coal 8 connected to the pipe 35 and serving as a raw material
Hopper 9 for injecting gas into the pipe 35 and a gasifier 10
Heat recovery boiler 12 connected to product gas extraction pipe 11
A heat recovery boiler 12, a pipe 30 having a valve 15 interposed therebetween, a char filter 13 having a gas input side connected thereto, a pipe 31 connected to a gas outlet side of the char filter 13 interposed with a valve 16, and a blower A pipe 41 connecting a pipe 36 downstream of the valve 37 and an upstream side of the valve 37 to the starting burner 23 via a valve 41; a pipe 35 upstream of the valve 15;
A bypass pipe 32 connecting the downstream pipe 31 via valves 14 and 17; a pipe 35 downstream of the blower 39 and upstream of the connection position of the coal hopper 9; and a pipe 30 downstream of the valve 15. Heat exchanger 2 which is nitrogen heating means for heating
A pipe 34 connected through the valve 2 and the valve 19;
A pipe 33 connected to the upstream pipe 31 with the valve 20 interposed
And is configured.

The downstream side of the pipe 31 is connected to a gas purification facility including a water washing tower in the next step. The pipe 33
Is open to the atmosphere at the downstream end.

The air separation device 1 includes an air compressor 3 for taking in and compressing the air 2, a heat exchanger 4 arranged with a heating-side fluid inlet connected to a discharge side of the air compressor 3, and a heat exchanger 4. A rectifying tower 5 arranged so that a raw air inlet is connected to a heating fluid outlet of the heat exchanger 4; a nitrogen outlet of the rectifying tower 5 and one of the heated fluid inlets of the heat exchanger 4 are connected;
Nitrogen extraction pipe 7 connected to one of the heated fluid outlets
And an oxygen outlet pipe 6 that connects the oxygen outlet of the rectification column 5 to the other heated fluid inlet of the heat exchanger 4 and is connected to the other heated fluid outlet of the heat exchanger 4. It is configured. The pipe 35 is connected to a downstream end of the nitrogen extraction pipe 7, and the pipe 36 is connected to a downstream end of the oxygen extraction pipe 6.

The heating fluid flows through the flow path of the heat exchanger 22 on the heating fluid side, and the pipe 34 is connected to the heat exchanger 2.
2 are connected to the heated fluid side flow path.

The operation of the apparatus having the above configuration will be described below.

The air 2 as a raw material in the air separation equipment 1 is pressurized by an air compressor 3, cooled in a heat exchanger 4, and then led to a rectification column 5, where oxygen and nitrogen are separated. The separated oxygen and nitrogen are sucked by the blowers 40 and 39, respectively, heated by the heat exchanger 4, and taken out.

At the time of startup, high-temperature combustion exhaust gas is generated by burning light oil 18 serving as fuel in the start burner 23 of the coal gasifier 10 with oxygen supplied under pressure by a blower 40, and the combustion exhaust gas is converted into gas. Through the gasifier 10 and the heat recovery boiler 12, the char filter 13 is bypassed (the valves 14 and 17 are opened and the valves 15 and 16 are closed in advance), and the char filter 13 is led to the water washing tower of the gas purification facility.
0, heat the heat recovery boiler 12 and the piping. At the time of startup, the valves 19 and 20 are opened, and a part of the nitrogen pressurized by the blower 39 is heated to 100 ° C. or more by the steam 21 in the heat exchanger 22 and then introduced into the char filter 13. The heating temperature is determined in consideration of the heat resistance of the material of the char filter 13, but it is generally preferable that the heating temperature does not exceed 500 ° C.

When the temperature of the combustion exhaust gas at the outlet of the valve 17 and the temperature of the heating nitrogen at the outlet of the char filter 13 become equal to or higher than the dew point of the produced gas, the temperature raising operation at the start is completed,
More fine coal 8 is supplied to the gasification furnace 9 by transporting with nitrogen, and gasification of coal is started using oxygen as an oxidant. After the start of gasification, the valves 15, 16 are opened, and the valves 14, 17, 19,
20 is closed, and the produced gas is led to the char filter 13. The supply of nitrogen and steam 21 to the heat exchanger 22 is also stopped at this point.

According to the present embodiment, at the time of start-up, the char filter 13 is directly heated by the nitrogen heated by the steam 21 in the heat exchanger 22, so that the start-up time of the coal gasification plant and the steam required at the start-up And the amount of utilities such as fuel can be reduced.

As another embodiment of the present invention, a method of indirectly heating nitrogen by using a heating furnace instead of the heat exchanger 22 or a method of circulating and using the nitrogen (pipe 20)
Is connected to the inlet side of the blower 39 so that circulation is possible).

The present invention is applicable to any coal gasification apparatus having an air separation facility, such as an integrated coal gasification combined cycle power plant (IGCC), a combined coal gasification fuel cell combined cycle plant (IGFC), and other plants for chemical raw materials. it can.

[0021]

According to the present invention, at the time of start-up, the char collecting means is directly heated by the heated nitrogen, so that the start-up time of the coal gasification plant and the amount of utilities such as steam and fuel required at the start-up time. Can be reduced.

[Brief description of the drawings]

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

FIG. 2 is a system diagram showing a main configuration of a coal gasifier showing an example of a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Air separation equipment 2 Air 3 Air compressor 4 Heat exchanger 5 Rectification tower 6 Oxygen extraction pipe 7 Nitrogen extraction pipe 8 Fine coal 9 Coal hopper 10 Gasifier 11 Generated gas extraction pipe 12 Heat recovery boiler 13 Char filter 14, 15, 16, 17 valve 18 light oil 19, 20 valve 21 steam 22 heat exchanger 23 starting burner 30, 31 pipe 32 bypass pipe 33, 34, 35, 36 pipe 37, 38 valve 39, 40 blower 41 pipe

Claims (3)

[Claims] 1. A coal comprising: an air separation facility for separating nitrogen from air, for transporting the separated nitrogen to a gasification raw material; and a char collecting means for collecting char from generated gas. In the gasifier, a heating nitrogen heating means for heating the nitrogen taken out from the air separation equipment and a pipe for introducing the nitrogen heated by the heating nitrogen heating means to the char collecting means are provided. A coal gasifier characterized by the following. 2. Coal comprising: an air separation facility for separating nitrogen from air and providing the separated nitrogen for transport of a gasification raw material; and a char collection means for collecting char from generated gas. In the method for starting the gasifier, the method includes heating the nitrogen taken out from the air separation facility, and raising the temperature of the char collecting means using the heated nitrogen. To start a coal gasifier. 3. The method for starting a coal gasifier according to claim 2, wherein the heating temperature of the nitrogen is 100 ° C. or more and 500 ° C. or less.