JP2002250206A - Coal gasification power generation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent misfire of a gas firing apparatus, by ensuring a minimum gas flow rate required to keep combustion of the gas firing apparatus, in a coal gasification power generation system. SOLUTION: In a coal gasification furnace 8, combustible gas is generated from fine powder carbon and gasifying agent. After removing char 13 from the combustible gas by a cyclone 17 and a char filter 18, the combustible gas is demineralized by a flushing column 24, and is desulfurized by an absorbing column 26 to be purified gas 29. A gas turbine 31 is rotated by using the Purified gas 29 as fuel, and a power generator 32 is driven by the rotations of the gas turbine. The gas firing apparatus 38 is disposed to burn the purified gas 29 at the time of trip or fluctuation of load of the gas turbine 31. A pressure regulating valve 39 is disposed in front of the gas burning apparatus 38, and the opening angle of the pressure regulating valve 39 is controlled so that the pressure in the coal gasification furnace 8 is constant. A flowmeter 40 and a flow regulating valve 41 are disposed parallel with the pressure regulating valve 39, so that the minimum flow rate of the purified gas 29 required for keeping the combustion is introduced into the gas burning apparatus 38.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to a coal gasification power generation system for generating electric power by burning a combustible gas generated from coal by a turbine.

[0002]

2. Description of the Related Art In general, in a coal gasification power generation system, a coal gasification furnace that generates flammable gas by reacting pulverized coal with a gasifying agent, and collects and collects char generated when flammable gas is generated. A desalination device including a cyclone, a char filter, a water washing tower, and the like; a gas purification device for desulfurizing sulfur in combustible gas; a gas turbine for obtaining a rotational driving force by burning the purified gas after desulfurization; A generator driven by the gas turbine to generate power.

[0003] The above coal gasification power generation system includes:
A gas incinerator is provided for incinerating purified gas when a gas turbine trips or changes in load. A part of the purified gas supplied to the gas turbine is introduced into the gas incinerator, and a pressure control valve is provided in the middle of the introduction line. The opening of the pressure control valve is controlled so that the pressure in the coal gasifier becomes constant. In addition, a lower limiter is attached to the pressure regulating valve in order to secure the minimum fuel of the gas incinerator, and the pressure regulating valve is considered not to be fully closed.

[0004]

However, according to the above-mentioned conventional technology, since the equipment volume from the coal gasifier to the gas incinerator is large, the pressure control is delayed. Further, when the output of the gas turbine changes, hunting may occur in the pressure control valve. Further, when the pressure of the coal gasifier fluctuates and the pressure drops, the pressure regulating valve narrows the opening of the valve in order to control the pressure to be constant. As a result, the amount of purified gas introduced into the gas incinerator decreases, but when the pressure drops below a predetermined pressure, the flow rate decreases due to a decrease in the primary pressure of the pressure control valve, and the minimum gas required for the gas incinerator is reduced. The amount cannot be secured, and the gas incinerator may misfire.

[0005] A method of setting the minimum opening (lower limiter) large in order to secure a flow rate when the pressure is extremely reduced may be considered, but this method has a problem that the control range of the pressure regulating valve is narrowed. Occurs.

SUMMARY OF THE INVENTION It is an object of the present invention to improve the safety and reliability of the entire system by preventing a gas incinerator from misfiring by securing a minimum gas flow rate necessary for holding the combustion of the gas incinerator. It is to provide a coal gasification power generation system that can be used.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a coal gasifier for producing a combustible gas by reacting pulverized coal with a gasifying agent, and burning the combustible gas. A gas turbine that obtains rotational driving force, a generator that is driven by the gas turbine to generate power, a gas incinerator that incinerates the combustible gas when the gas turbine trips or changes in load, and a gas incinerator that A pressure control valve, which is provided in the middle of the line for introducing the combustible gas and whose opening is controlled so that the pressure in the coal gasifier becomes constant, the coal gasification power generation system comprising: The gas incinerator is characterized in that a flow control valve for supplying a minimum flow of flammable gas required for holding the combustion to the gas incinerator is provided in parallel with the pressure control valve.

According to the above configuration, even when the opening degree of the pressure control valve is reduced and the flow rate of the gas introduced into the gas incinerator decreases, the required minimum flow rate of the flammable gas is always kept constant by the flow control valve. Since it is introduced into the gas incinerator, misfire of the gas incinerator can be prevented.

Further, in the present invention, a flow meter for measuring the flow rate of the combustible gas to the gas incinerator is provided. The opening of the flow control valve is controlled based on the measurement result of the flow meter so that the minimum flow rate of the combustible gas is constant.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows the overall configuration of a coal gasification power generation system according to the present invention. As shown in the drawing, coal 1 is pulverized by a pulverizer 2 into pulverized coal, introduced into a hot-air generating furnace 3, and dried by a high-temperature heating gas generated in the hot-air generating furnace 3. The dried coal 1 is temporarily stored in a hopper 4, then pressurized by a lock hopper system 5, further conveyed by a carrier gas 7 pressurized by a compressor 6, and supplied to a coal gasifier 8. You. In addition, air 10
Is separated into nitrogen and oxygen in the rectification column 12, a part of the nitrogen is used as the carrier gas 7 for transporting the coal 1 after the above-mentioned drying, and the remainder is used as the carrier gas 7a for transporting the char 13. Oxygen is pressurized by the compressor 14 as a gasifying agent and is supplied to the coal gasifier 8.
Sent to

In the gasification section of the coal gasifier 8, the coal 1 is gasified by the oxygen, and at the same time, the slag 15 flows down from the bottom of the gasifier. The product gas generated in the coal gasifier 8 is cooled by the syngas cooler 16 and then introduced into the cyclone 17 and the filter 18 where the char 1
3 is collected. The collected char 13 is a hopper 19
-20, and as described above, the rectification column 1
The gas is sent to the coal gasifier 8 by the carrier gas 7a such as nitrogen gas from the fuel cell 2 and recycled.

On the other hand, the cyclone 17 and the filter 18
The product gas passed through is cooled in the water washing tower 24,
It is introduced into the absorption tower 26. The generated gas is supplied to the absorption tower 2
At 6, sulfur compounds such as hydrogen sulfide and carbonyl sulfide are removed to produce purified gas 29.

The purified gas 29 is introduced into a gas turbine 31. In the gas turbine 31, the purified gas 29 is burned and rotated, and the rotating force drives the generator 32 to rotate. The combustion exhaust gas after driving the gas turbine 31 is sent to the waste heat recovery boiler 33, and is discharged into the atmosphere from the chimney 34 after the waste heat recovery.

In the syngas cooler 16 and the waste heat recovery boiler 33, steam is generated by heat exchange. The generated steam 35 from the syngas cooler 16 and the generated steam 36 from the waste heat recovery boiler 33 are sent to a steam turbine 37, The turbine 37 is rotated. The steam turbine 37 also drives the generator 32 to rotate.

The coal gasification power generation system is provided with a gas incinerator 38. Usually, most of the purified gas 29 is introduced into the gas turbine 31 and a part of the purified gas 29 is sent to the gas incinerator 38. However, during operation of the power generation system, the gas turbine 31 trips or the load suddenly changes. In this case, the purified gas 29 to the gas turbine 31 is introduced into the gas incinerator 38 and incinerated. In the gas incinerator 38, the gas turbine 31
The standby operation is always performed in preparation for a trip or sudden change in load. In the stand-by operation, light oil may be burned. However, in order to reduce the power generation cost, the purified gas 29 is normally branched and a part of the purified gas 29 is introduced into the gas incinerator 38, whereby the standby operation is performed. Done.

A pressure regulating valve 39 is provided in the middle of the line for introducing the purified gas 29 into the gas incinerator 38. By adjusting the opening of the pressure control valve 39,
The pressure in the coal gasifier 8 is controlled to be constant. In order to ensure the minimum gas flow rate of the gas incinerator 38, a lower limiter is attached to the pressure control valve 39 so that the pressure control valve 39 cannot be fully closed.

In the middle of the line for introducing the purified gas 29 into the gas incinerator 38, a flow meter 40 and a flow control valve 42 are provided in parallel with the pressure control valve 39. The flow meter 40 measures the flow rate of the purified gas 29 introduced into the gas incinerator 38 through the flow control valve 41, and the opening of the flow control valve 41 is controlled based on the measurement result of the flow meter 40. Is done.

According to the above configuration, when the opening of the pressure control valve 39 decreases and the flow rate of the purified gas 29 to the gas incinerator 38 decreases, the opening of the flow control valve 41 changes. The required minimum flow rate of the purified gas 29 is always constantly introduced into the gas incinerator 38. This makes it possible to prevent misfire of the gas incinerator 38.

In the figure, 11, 22, 25 are heat exchangers, 23 is a tank, 27 is a regenerator, 28 is a regeneration waste gas processing section, and 30 is a fuel cutoff valve.

[0020]

As described above, according to the present invention,
Since the minimum gas flow rate of the combustible gas to the gas incinerator is ensured, misfire in the gas incinerator can be prevented. As a result, the safety and reliability of the entire power generation system can be improved.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a coal gasification power generation system according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Coal 2 Crusher 3 Hot air generator 5 Lock hopper system 6,14 Compressor 7,7a Carrier gas 8 Coal gasifier 10 Air 12 Rectification tower 13 Char 15 Slag 16 Syngas cooler 17 Cyclone 18 Filter 24 Water washing tower 26 Absorption tower 29 Purified gas 31 Gas turbine 32 Generator 33 Waste heat recovery boiler 34 Chimney 35, 36 Generated steam 37 Steam turbine 38 Gas incinerator 39 Pressure control valve 40 Flow meter 41 Flow control valve

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F01D 17/00 F01D 17/00 J Q N (72) Inventor ▲ Hiro ▼ Yuichiro No. 6 Takaracho, Kure City, Hiroshima Prefecture No. 9 Babcock Hitachi Co., Ltd. Kure Plant (72) Inventor Yoshiki Watanabe 6-9 Takaramachi, Kure City, Hiroshima Prefecture Bubcock Hitachi Co., Ltd. Kure Plant F-term (reference) 3G071 AB01 BA09 BA22 CA03 CA09 DA11 FA05 GA06 HA04 JA04 3G081 BA02 BA13 BB00 BC07 BD00 DA21

Claims (2)

[Claims] 1. A coal gasifier for producing a combustible gas by reacting pulverized coal with a gasifying agent, a gas turbine for burning the combustible gas to obtain a rotational driving force, and a gas turbine driven by the gas turbine. A generator for generating electricity, a gas incinerator for incinerating the combustible gas when the gas turbine trips or changes in load, and a gas incinerator provided in the middle of a line for introducing the combustible gas into the gas incinerator, A pressure regulating valve whose opening is controlled so that the pressure in the gasification furnace is constant, and a coal gasification power generation system comprising: a combustible gas having a minimum flow rate required for maintaining combustion in the gas incinerator. A coal gasification power generation system, wherein a flow control valve for flowing gas into the gas incinerator is provided in parallel with the pressure control valve. 2. The coal gasification and power generation system according to claim 1, further comprising a flow meter for measuring a flow rate of the combustible gas to the gas incinerator, wherein the flow control valve measures the flow rate by the flow meter. A coal gasification power generation system characterized in that the opening is controlled based on the result so that the minimum flow rate of combustible gas is constant.