JPH10325505A - Gasification compound power generation equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve a higher heat efficiency by a method wherein water is extracted at an intermediate point or an outlet of an economizer of a waste heat recovery boiler, utilized to cool a device to be cooled in equipment and the extracted water after the cooling is recovered into the waste heat recovery boiler to prevent low temperature corrosion. SOLUTION: In cooling water for a high pressure device of gasification equipment 4, it is better that the pressure thereof is higher than that in a furnace and the temperature thereof is higher than about 160 deg.C, for instance. Therefore, an intermediate header 20 of an economizer 9 is provided at a point where the temperature of feed water is, for example, 180 deg.C a little on the upstream side from an outlet of the economizer 9 and water is extracted from the economizer 9 as water for cooling the high pressure device of the gasification equipment 4 to cool a burner nozzle or the like of the gasification equipment 4. Thereafter, the water is superheated up to about 220 deg.C to be recovered into a steam drum 13 of the waste heat recovery boiler 7. At this point, the water used for cooling the high pressure device of the gasification equipment 4 is used as a part of the economizer 9 as for the waste heat recovery boiler 7 and as feed water into the waste heat recovery boiler 7 in the recovery of the water for cooling the high pressure device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combined gasification and power generation system capable of preventing low-temperature corrosion and improving thermal efficiency.

[0002]

2. Description of the Related Art FIG. 3 shows a cooling water system for high-pressure equipment in a conventional integrated gasification combined cycle facility. The integrated gasification combined cycle facility has many devices and facilities. Here, an example of a high-pressure equipment cooling water system is shown. As a high-pressure equipment cooling water system of the integrated gasification combined cycle facility, a condenser 1 of a steam turbine and a high-pressure equipment cooling water pump 2 are provided. It is connected to. Usually, the condensed water of about 30 ° C. is sent out as cooling water by the high-pressure equipment cooling water pump 2 in order to cool the equipment in various parts of the gasification facility 4. In the gasification facility 4, the high-pressure cooling water flows from the high-pressure cooling water supply main pipe 3 to various places, for example, a burner nozzle, a furnace monitoring device, a gas sampling device, etc., and cools, that is, absorbs heat, and It returns to the mother pipe 5.

The pressure of the high-pressure cooling water flowing into the high-pressure cooling water return mother pipe 5 is adjusted by a cooling water pressure regulating valve 6 to a value higher than the pressure in the furnace of the gasification facility. This is because even if the cooling water pipe leaks, the gas in the furnace is prevented from flowing back to the cooling water system, and if the pressure is too low, the cooling water easily boils and the cooling capacity is reduced. After the high-pressure cooling water passes through the cooling water pressure control valve 6, the water is recovered.
The amount of heat collected and absorbed by the condenser 1 is radiated to seawater in the condenser 1.

[0004]

However, in the prior art described above, cooling water of about 30 ° C. flows to various places such as the burner nozzle of the gasification facility 4, but the temperature is too low, so that a local or unheated part is not heated. Low-temperature corrosion occurs on the surface of the part cooled at low temperature in the furnace, such as when the gasification facility 4 is started or stopped. In addition, there is a problem that the heat absorbed during cooling is radiated to the seawater without being recovered, thereby lowering the thermal efficiency.

[0005] It is an object of the present invention to solve the above-mentioned problems, to provide a gasification combined cycle power plant capable of preventing low-temperature corrosion and improving thermal efficiency.

[0006]

In order to solve the above-mentioned problems, the present invention provides a gasifier, a gas turbine exhaust heat recovery boiler,
And a gasification combined cycle power plant having a steam turbine condenser, water is extracted from the middle or outlet of the economizer of the waste heat recovery boiler, and this is used for cooling equipment to be cooled in the facility, and after cooling. The present invention is configured to collect the extracted water in the exhaust heat recovery boiler. The present invention resides in that the equipment to be cooled is a cooling pipe constituting a furnace of a gasification furnace.
Further, the present invention is characterized in that a means for measuring a flow rate and an inlet / outlet temperature of the cooling water passing through the equipment to be cooled is provided. Further, the present invention provides a gasification combined cycle power plant having a gasifier, a gas turbine exhaust heat recovery boiler, and a steam turbine condenser, wherein water or steam is extracted or extracted from the exhaust heat recovery boiler. After having been used for the purpose, while having a system to recover to the waste heat recovery boiler again,
A rapid blow valve is provided in the water system of the exhaust heat recovery boiler.

[0007]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a diagram of a high-pressure cooling water system of an integrated gasification combined cycle power generation system showing a first embodiment of the integrated gasification combined cycle power generation system according to the present invention. It is shown as follows. In the integrated gasification combined cycle power plant of the present invention, in FIG. 1, a waste heat recovery boiler (“H”) for recovering heat from exhaust gas of a gas turbine is provided to a condenser 1 of a steam turbine and a gasification facility 4.
RSG ”). A pipe 101 connecting the exhaust heat recovery boiler 7 and the condenser 1 is provided with a water supply pump 8 for the exhaust heat recovery boiler. The waste heat recovery boiler feedwater pump 8 supplies condensate from the condenser 1 to the waste heat recovery boiler 7. The condensed water supplied by the waste heat recovery boiler feed water pump 8 is supplied to the economizer 9 of the waste heat recovery boiler 7 and heated.

[0009] The economizer 9 is provided with an economizer inlet pipe 10 and an ecommerce outlet pipe 11. The feedwater pump 8 is connected, and a steam drum 13 is connected to a pipe 102 on the side of the economizer outlet pipe 11 via a feedwater flow control valve 12. A pipe 103 is branched in the middle of the pipe 102, and supplies water to the heat exchanger of the gasification facility via the high-pressure water supply pump 18 connected to the pipe 103.

The feed water heated by the economizer 9 is supplied to a steam drum 13 after its flow rate is adjusted by a feed water flow rate adjusting valve 12. The steam drum 13 is connected to the evaporator 15 of the exhaust heat recovery boiler 7 via pipes 201 and 202, and circulates can water by a waste heat recovery boiler circulation pump 14 provided in the pipe 201. is there. Steam is generated in the evaporator 15 by the exhaust heat of the gas turbine, and steam-water separation is performed in the steam drum 13. The steam in the steam drum 13 is guided to a downstream superheater by a steam pipe 16. The water level of the steam drum 13 is controlled by the feedwater flow control valve 12, and the rapid blow valve 17 is connected to the pipe 301 connecting the steam drum 13 and the condenser 1 so as to cope with a sudden sudden change in the drum water level. And is discharged to the condenser 1 side.

In the middle of the economizer 9 of the exhaust heat recovery boiler 7, an economizer intermediate pipe 20 is provided. From the economizer intermediate pipe 20, a high pressure cooling water flow control valve 21 is provided. A part of the feedwater is extracted and used as cooling water for the high-pressure equipment of the gasification facility 4 through the pipeline 401 through the high-pressure cooling water supply mother pipe 3. As a position where the economizer intermediate pipe 20 is provided, it is desirable that the feedwater temperature is about 180 ° C. slightly upstream of the outlet of the economizer 9. The cooling water used as the cooling water for the high-pressure equipment of the gasification facility 4 returns to the high-pressure cooling water return mother pipe 5, and the high-pressure cooling water return mother pipe 5 and the steam drum 13
Cooling water pressure regulating valve 6 provided in pipe 402 connecting
The water is supplied to the steam drum 13 after the pressure is adjusted.

Next, the operation of the present invention having the above configuration will be described. In the first embodiment, the pressure of the economizer 9 is about 60 kg / cm ² , and the feedwater flow rate to the exhaust heat recovery boiler 7 is controlled by the feedwater flow control valve 12. Although the inlet temperature is as low as about 30 to 60 ° C., the outlet temperature of the economizer 9 is operated as much as about 220 ° C.

On the other hand, for cooling water for high-pressure equipment in the gasification facility 4, the pressure is preferably higher than the pressure in the furnace, and the temperature is preferably higher than about 160 ° C. in order to prevent low-temperature corrosion of the equipment. Therefore, an intermediate economizer 20 is provided slightly upstream of the outlet of the economizer 9 at a feedwater temperature of about 180 ° C., and water is extracted from the economizer 9 for high-pressure equipment cooling water of the gasification facility 4. ,
After cooling the burner nozzle and the like of the gasification facility 4, it is superheated to about 220 ° C. and then recovered to the steam drum 13 of the exhaust heat recovery boiler 7 through the cooling water pressure regulating valve 6. At this time, the high-pressure equipment cooling water of the gasification facility 4 acts as a part of the economizer 9 for the exhaust heat recovery boiler 7, and the high-pressure equipment cooling water is recovered as it is to the exhaust heat recovery boiler 7. Acts as a water supply.

That is, according to the present invention, the high-pressure equipment cooling water extracted from the middle of the economizer 9 is high-temperature cooling water for the gasification equipment 4 to prevent low-temperature corrosion. For, it acts as a part of economizer 9,
It also recovers heat and is an invention of both advantages.

The high-pressure cooling water flow control valve 21 adjusts the cooling water flow required for each device such as the burner nozzle of the gasification facility 4, and the cooling water pressure control valve 6 irrespective of the pressure of the steam drum 13, Even if the cooling water pipe leaks, the pressure in the furnace is controlled to be higher than the pressure in the furnace of the gasification facility 4 so that the gas in the furnace does not flow back into the cooling water system.

The water level of the steam drum 13 is controlled by the feed water flow control valve 1.
2, a rapid blow valve 17 is provided so as to cope with a temporary sudden change in the drum water level at the start and end of the extraction of the high-pressure equipment cooling water. The discharge destination of the quick blow valve 17 may be the condenser 1 to collect water, and since it is temporary, it may be discarded into a flash pipe or the like.

Next, FIG. 2 shows a second embodiment of the present invention, and is a system diagram showing a bottom cooling water system of a gasification furnace of an integrated gasification combined cycle facility. In this case, the same parts as those in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted.

The gasification furnace 26 of this embodiment has a still water circulation system 31 for circulating cooling water to shield the gasification furnace pressure vessel 25 from heat, but is heated by the economizer 9 of the exhaust heat recovery boiler 7. A part of the supplied water is used as cooling water for the furnace bottom 27 which constitutes a part of the gasification furnace 26. In this embodiment, a middle part 20 of the economizer 9 is provided in the middle of the economizer 9.
The cooling water is supplied to the furnace bottom 27 of the gasification facility 4 through the high-pressure cooling water flow control valve 21 provided in the pipe 501 for supplying water at the bottom of the gasification facility 4. The cooling water that has cooled the furnace bottom 27 of the gasification facility 4 is supplied to a cooling water pressure regulating valve 6 provided in a pipe 502 returning from the furnace bottom 27 to the steam drum 13.
After the pressure is adjusted by the above, water is supplied to the steam drum 13.
A furnace bottom cooling water flow meter 30 is provided in the pipe 501 as a flow rate measuring means, and the furnace bottom cooling water flow meter 30 measures the flow rate of the furnace bottom cooling water. In addition, the gasification equipment 4 of the pipeline 501
A cooling water inlet temperature detector 28 is provided near the furnace bottom 27 as a temperature measuring means to measure the temperature of the cooling water on the furnace bottom 27 inlet side. A cooling water outlet temperature detector 29 is provided in a pipe 502 on the cooling water outlet side.
7 detects the outlet temperature. A steam / water separation drum 32 is provided in a pipeline 601 constituting the canned water circulation system 31, and the steam separated by the steam / water separation drum 32 is sent to a steam turbine or an exhaust heat recovery boiler through a steam pipe 33. . This steam is supplied to the same heat exchanger of the gasification facility as the steam sent from the high-pressure water supply pump 18.

In the second embodiment, the pressure of the economizer 9 is about 60 kg / cm ² , and the flow rate of the water supplied to the exhaust heat recovery boiler 7 is controlled by the water supply flow rate regulating valve 12. Table 9
The inlet temperature is as low as about 30 to 60 ° C., but the outlet temperature of the economizer 9 is operated at a considerably high level of about 220 ° C.

On the other hand, for cooling water for high-pressure equipment in the gasification facility 4, the pressure is preferably higher than the pressure in the furnace, and the temperature is preferably higher than about 160 ° C. in order to prevent low-temperature corrosion of the equipment. Because there are many parts, instead of evaporating tubes with gas-solid two-phase flow,
It is better to cool in the range of compressed water that does not include evaporation. That is, when accompanied by evaporation, the steam stays above the tube on the heating surface side of the furnace bottom tube, significantly deteriorating heat transfer on the heating surface side,
This is because the furnace bottom cooling tube is easily burned. Therefore, an intermediate pipe 20 for the economizer is provided slightly upstream of the outlet of the economizer 9 at a feedwater temperature of about 180 ° C., and water is extracted from the economizer 9 for cooling the bottom of the gasification facility 4. After cooling the furnace bottom of the gasification facility 4, it is superheated to about 220 ° C., and then recovered to the steam drum 13 of the exhaust heat recovery boiler 7 via the cooling water pressure regulating valve 6.

At this time, the furnace bottom cooling water of the gasification facility 4 acts as a part of the economizer 9 for the exhaust heat recovery boiler 7, and the recovery of the furnace bottom cooling water is performed as it is. Acting as a water supply to 7. Further, when using saturated water accompanied by evaporation of boiler water or the like as furnace bottom cooling water, the amount of heat absorbed at the furnace bottom cannot be measured from the boiler water temperature because the boiler water temperature is constant. However, when cooling in the range of compressed water that does not include evaporation according to this embodiment, the flow rate of the cooling water is measured by the furnace bottom cooling water flow meter 30, and the cooling water inlet temperature detector 28 and the cooling water outlet temperature detector are measured. By measuring the temperature at 29, the amount of heat absorbed at the furnace bottom can be easily measured.

That is, according to the present invention, the furnace bottom cooling water extracted from the middle of the economizer 9 prevents low-temperature corrosion for the gasification facility 4 and provides more safe cooling water against cooling pipe burnout. Yes, it can measure the amount of heat absorbed at the furnace bottom. Further, the exhaust heat recovery boiler 7 acts as a part of the economizer 9 and recovers heat in the whole plant, thereby improving not only reliability of the equipment but also economy. In the above embodiment, the cooling water used to cool the equipment to be cooled in the facility is placed at a location where the feedwater temperature is about 180 ° C. slightly upstream of the outlet of the economizer of the exhaust heat recovery boiler. Although water is extracted by providing the pipe 20, water may be extracted from the middle or the outlet of the economizer depending on the cooling water temperature.

[0023]

As described above, according to the integrated gasification combined cycle system of the present invention, the following effects can be obtained. Since the equipment to be cooled is cooled by using the furnace bottom cooling water extracted from the middle or outlet of the economizer, low temperature corrosion can be prevented for the gasification facility. Since the cooling water extracted from the middle or outlet of the economizer of the economizer is used, the cooling water is safer against burnout of the cooling pipe. In addition, the waste heat recovery boiler acts as a part of the economizer, and the entire plant recovers heat, not only improving the reliability of the equipment, but also has excellent economic efficiency. The flow rate measuring means and the temperature measuring means measure the flow rate of the cooling water passing through the equipment to be cooled and the inlet / outlet temperature, so that the heat absorption of the cooling section can be measured. Since the rapid blow valve is provided in the water system of the exhaust heat recovery boiler, it is possible to cope with a temporary sudden change in the drum water level at the start and end of the extraction of the high-pressure equipment cooling water.

[Brief description of the drawings]

FIG. 1 is a system diagram showing a first embodiment of an integrated gasification combined cycle facility according to the present invention.

FIG. 2 is a system diagram showing a second embodiment of the integrated gasification combined cycle system according to the present invention.

FIG. 3 is a system diagram showing a conventional integrated gasification combined cycle facility.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Condenser 3 High-pressure cooling water supply main pipe 4 Gasification equipment 5 High-pressure cooling water return main pipe 6 Cooling water pressure control valve 7 Waste heat recovery boiler 8 Water supply pump for waste heat recovery boiler 9 Energy saving device 10 Energy saving device inlet Near pipe 11 Conservation unit outlet pipe 12 Feed water flow control valve 13 Steam drum 14 Exhaust heat recovery boiler circulation pump 15 Evaporator 16 Steam pipe 17 Rapid blow valve 18 High pressure water supply pump 20 Middle pipe of coal saver 21 High pressure cooling water flow rate Control valve 25 Gasification furnace pressure vessel 26 Gasification furnace 27 Furnace bottom 28 Cooling water inlet temperature detector 29 Cooling water outlet temperature detector 30 Furnace bottom cooling water flow meter 31 Can water circulation system

Continued on the front page (51) Int.Cl. ⁶ Identification code FI C10J 3/72 C10J 3/72 F F22B 1/18 F22B 1/18 H

Claims (4)

[Claims] 1. In a gasification combined cycle power plant having a gasification furnace, a gas turbine exhaust heat recovery boiler, and a steam turbine condenser, water is extracted from an intermediate or outlet of the economizer of the exhaust heat recovery boiler, This is used for cooling equipment to be cooled in the equipment, and the extracted water after cooling is recovered in the exhaust heat recovery boiler. 2. The integrated gasification combined cycle system according to claim 1, wherein the equipment to be cooled is a cooling pipe constituting a furnace of a gasification furnace. 3. The integrated gasification combined cycle system according to claim 1, further comprising means for measuring a flow rate and a temperature of an inlet / outlet of the cooling water passing through the equipment to be cooled. 4. In a gasification combined cycle power plant having a gasifier, a gas turbine exhaust heat recovery boiler, and a steam turbine condenser, water or steam is extracted or extracted from the exhaust heat recovery boiler, An integrated gasification combined cycle facility comprising a system for recovering the waste heat recovery boiler after use for a purpose, and a rapid blow valve provided in a water system of the waste heat recovery boiler.