阅读说明：本技术 一种气化显热综合利用生产煤气和焦油的系统 (System for gasification sensible heat comprehensive utilization production coal gas and tar ) 是由 俞平 于 2020-07-22 设计创作，主要内容包括：本发明所提供的是一种气化显热综合利用生产煤气和焦油的系统,以高挥发份的固体燃料来生产煤气和焦油,其能量转换率高,还能独立输出煤气或以煤气为燃料来代替不适合锅炉燃烧的煤来发电,与常规燃煤火电站联合使用时,则能提供比各自独立使用更高的调峰供电能力,同时还能产出一定的高附加值焦油的一种多联产系统,而干馏产生的半焦则在系统的气化环节中也当燃料消耗掉了,使用的初级燃料是煤或含挥发份的固体燃料,尤其适合于高挥发份和水分的燃料。(The invention provides a system for producing coal gas and tar by comprehensively utilizing gasification sensible heat, which produces the coal gas and the tar by using high-volatile solid fuel, has high energy conversion rate, can independently output the coal gas or use the coal gas as fuel to replace coal which is not suitable for boiler combustion to generate electricity, can provide higher peak regulation power supply capacity than that of the coal gas and the tar which are independently used when being used together with a conventional coal-fired thermal power station, and can also produce certain high-added-value tar.)

1. A system for producing coal gas and tar by comprehensively utilizing gasification sensible heat comprises a circulating fluidized bed gasification furnace, a tar separation device, a coal gas waste heat boiler and an air blower, wherein coal or solid fuel containing volatile matters is taken as a raw material, a part of the coal or the solid fuel containing the volatile matters is firstly put into a dry distillation tank, converted into semicoke and then put into a gasification furnace, the heat value and the volatile matters content of the gasification furnace fuel meet or exceed the minimum requirement of the operation of the gasification furnace by being matched with corresponding coal or solid fuel containing the volatile matters according to the heat value and the residual volatile matters content of the semicoke, the yield of the semicoke is determined according to the semicoke requirement in the total consumption of the gasification furnace fuel, the system can provide coal gas and coal tar with high added value required by a user while producing the semicoke quantity required by the gasification furnace, an outlet of the circulating fluidized bed gasification furnace is connected to the dry distillation tank, and the coal or solid fuel containing the volatile matters absorbs the sensible heat in raw coke to produce the coal gas or the The evaporation of volatile matter in the solid fuel come out, still filter the dust in the coal gas together with the semicoke layer simultaneously, the coal gas that comes out to contain volatile matter gets into purifier cooling to congeal the mixed liquid of water and tar and the coal gas takes off the liquid, separates out its characterized in that with tar from the aquatic again: a gas waste heat boiler is arranged between the outlet of the circulating fluidized bed gasification furnace and the inlet of the dry distillation tank, the amount of semicoke produced by the dry distillation tank is controlled by adjusting the heat exchange amount of the gas waste heat boiler, so that the balance of materials under different conditions is realized, or part of the cooled and dewatered gas is extracted from the outlet of the tar separation device by a return fan and is injected back into the inlet of the dry distillation tank to keep the gas at the inlet of the dry distillation tank at a proper temperature while the gas waste heat boiler is arranged, so that the components and the quality of semicoke and crude gas are controlled, the produced semicoke is sent to the circulating fluidized bed gasification furnace for air blowing as fuel, or the hot semicoke is cooled by spraying water through a semicoke regenerator and then is supplied to the gasification furnace, the water is evaporated into steam, the semicoke regenerator is also connected with an air blower, the blown air and the steam enter the gasification furnace together to produce.

2. The system for producing coal gas and tar by comprehensive utilization of gasification sensible heat according to claim 1, wherein: a bypass coal outlet is arranged between the raw gas inlet and the raw gas outlet of the retort, part of the coal is discharged from the bypass outlet to the gasification furnace after being dried, the rest of the coal is carbonized into semicoke and discharged from a semicoke hole, or the coal is divided into two compartments and is loaded with part of the coal, the coal is discharged from the bypass outlet after being dried, the other coal is discharged from the semicoke outlet after being loaded with the rest of the coal for carbonization, the dried coal is discharged from the bypass outlet, the discharged dried coal or solid fuel is mixed with the semicoke after carbonization and is sent to the gasification furnace to be used as fuel, and the water content of the fuel is reduced to improve the gasification efficiency.

3. The system for producing coal gas and tar by comprehensive utilization of gasification sensible heat according to claim 1 or 2, wherein: the solid fuel containing volatile matters comprises straw, biomass, waste rubber, waste plastic, organic garbage, petroleum coke or other solid fuels containing organic matters.

4. The system for producing coal gas and tar by comprehensive utilization of gasification sensible heat according to claim 1 or 2, wherein: the outlet pipeline of the tar separation device connects coal gas to a power generation boiler, reduces the ash content of fuel of the boiler, and is particularly beneficial to reducing coking and scaling of a boiler heat exchange surface taking low-ash fusion point coal as fuel.

5. The system for producing coal gas and tar by comprehensive utilization of gasification sensible heat according to claim 1 or 2, wherein: the gas pipeline at the outlet of the tar separation device is pressurized by a gas compressor and connected to a gas turbine as fuel, so that the power generation efficiency of the system can be improved.

6. The system for producing coal gas and tar by comprehensive utilization of gasification sensible heat according to claim 1, wherein: the coal gas pipeline at the outlet of the tar separation device is connected to a boiler and is also connected to a gas turbine through the pressurization of a coal gas compressor to be used as fuel, so that the power generation efficiency is improved, and the peak regulation flexibility is also enhanced.

7. The system for producing coal gas and tar by comprehensive utilization of gasification sensible heat according to claim 5, wherein: the gas waste heat boiler and the combined cycle waste heat boiler produce steam to drive the combined cycle steam turbine together, and the connection mode is that the steam produced by the two waste heat boilers is input into the same steam turbine to supply steam.

8. The system for producing coal gas and tar by comprehensive utilization of gasification sensible heat according to claim 1 or 2, wherein: the semicoke heat regenerator injects sewage discharged by the tar separation device so as to achieve the aim of zero waste liquid discharge.

9. The system for producing coal gas and tar by comprehensive utilization of gasification sensible heat, as recited in claim 8, is characterized in that: the semicoke outlet of the dry distillation tank is provided with a sealed delivery valve, the outlet of the sealed delivery valve is connected with the inlet of a semicoke regenerator, steam or inert gas is injected between the semicoke inlet of the semicoke regenerator and an air outlet, and heated air is isolated from coal gas leaked from the sealed delivery valve to prevent explosion caused by mixing of the heated air and the coal gas.

10. The system for producing coal gas and tar by comprehensive utilization of gasification sensible heat according to claim 1 or 2, wherein: the tar separation device comprises a water washing tower, an oil/water separator and an electric tar precipitator, coal gas flowing out of the retort enters the water washing tower for spray washing and cooling, tar is condensed and separated from water through the oil/water separator, sewage enters a sewage tank, tar is collected, and the coal gas flowing out of the spraying tower is supplied to users after tar and water are removed through the electric tar precipitator.

Technical Field

The invention relates to the field of power generation and tar production, in particular to a poly-generation system which can produce coal gas and tar by using high-volatile solid fuel, has high energy conversion rate, can independently output the coal gas or use the coal gas as fuel to replace coal which is not suitable for being combusted by a boiler to generate power, can provide higher peak regulation power supply capability than that of the respective independent use when being used together with a conventional coal-fired thermal power station, and can produce certain high-added value tar.

Background

In coal or solid fuel containing volatile matters, some solid fuel containing volatile matters in raw coal is easy to coke and deposit scale in the combustion and heat transfer processes of a boiler due to too low ash melting point, or is discharged and polluted too much after being directly combusted due to too high sulfur content, the raw coal needs to be prepared into coal gas with low ash content and little pollution for combustion, because the temperature in a circulating fluidized bed gasification furnace is lower than the temperature of a hearth of the boiler, the coal gas desulfurization is much lower than the flow of flue gas desulfurization treatment, and the value of byproducts is high, the gasification furnace is used as pretreatment equipment of the boiler fuel, so that the gasification furnace can help the boiler use the solid fuel which is not suitable for direct combustion, can be combined with a gas turbine to form IGCC clean and efficient power generation equipment for use, and can produce tar with high added.

Disclosure of Invention

A system for producing coal gas and tar by comprehensively utilizing gasification sensible heat comprises a circulating fluidized bed gasification furnace, a tar separation device, a coal gas waste heat boiler and an air blower, wherein coal or solid fuel containing volatile matters is taken as a raw material, a part of the coal or the solid fuel containing the volatile matters is firstly put into a dry distillation tank, converted into semicoke and then put into a gasification furnace, the heat value and the volatile matters content of the gasification furnace fuel meet or exceed the minimum requirement of the operation of the gasification furnace by being matched with corresponding coal or solid fuel containing the volatile matters according to the heat value and the residual volatile matters content of the semicoke, the yield of the semicoke is determined according to the semicoke requirement in the total consumption of the gasification furnace fuel, the system can provide coal gas and coal tar with high added value required by a user while producing the semicoke quantity required by the gasification furnace, an outlet of the circulating fluidized bed gasification furnace is connected to the dry distillation tank, and the coal or solid fuel containing the volatile matters can absorb the sensible heat in raw coke to produce the coal or solid coal containing Volatile matters in the bulk fuel are evaporated, dust in the coal gas is filtered together with the semicoke layer, the coal gas containing the volatile matters is cooled in a purifying device and condensed into mixed liquid of water and tar to remove liquid from the coal gas, the tar is separated from the water, a coal gas waste heat boiler is arranged between an outlet of a circulating fluidized bed gasification furnace and an inlet of a carbonization tank, the amount of the semicoke produced by the carbonization tank is controlled by adjusting the heat exchange amount of the coal gas waste heat boiler so as to realize material balance under different conditions, or the coal gas after partial cooling and liquid removal is extracted from the outlet of a tar separating device by a return fan and is injected back into the inlet of the carbonization tank so that the coal gas at the inlet of the carbonization tank is kept at proper temperature to control the components and the quality of the semicoke and the raw coal gas, the produced semicoke is sent to a circulating fluidized bed for air blast to serve as fuel, or the semicoke regenerator is used for cooling the hot semicoke and then supplying the gasification furnace, the water is evaporated into steam, the semicoke regenerator is also connected with an air blower, blown air and the steam enter the gasification furnace together to produce coal gas, and cooled semicoke is sent to the gasification furnace to be used as fuel.

A bypass coal outlet is arranged between the raw gas inlet and the raw gas outlet of the retort, part of the coal is discharged from the bypass outlet to the gasification furnace after being dried, the rest of the coal is carbonized into semicoke and discharged from a semicoke hole, or the coal is divided into two compartments and is loaded with part of the coal, the coal is discharged from the bypass outlet after being dried, the other coal is discharged from the semicoke outlet after being loaded with the rest of the coal for carbonization, the dried coal is discharged from the bypass outlet, the discharged dried coal or solid fuel is mixed with the semicoke after carbonization and is sent to the gasification furnace to be used as fuel, and the water content of the fuel is reduced to improve the gasification efficiency. The solid fuel containing volatile matters comprises straw, biomass, waste rubber, waste plastic, organic garbage, petroleum coke or other solid fuels containing organic matters.

The outlet pipeline of the tar separation device connects coal gas to a power generation boiler, reduces the ash content of fuel of the boiler, and is particularly beneficial to reducing coking and scaling of a boiler heat exchange surface taking low-ash fusion point coal as fuel.

The gas pipeline at the outlet of the tar separation device is pressurized by a gas compressor and connected to a gas turbine as fuel, so that the power generation efficiency of the system can be improved.

The coal gas pipeline at the outlet of the tar separation device is connected to a boiler and is also connected to a gas turbine through the pressurization of a coal gas compressor to be used as fuel, so that the power generation efficiency is improved, and the peak regulation flexibility is also enhanced.

The gas waste heat boiler and the combined cycle waste heat boiler produce steam to drive the combined cycle steam turbine together, and the connection mode is that the steam produced by the two waste heat boilers is input into the same steam turbine to supply steam.

The semicoke heat regenerator injects sewage discharged by the tar separation device so as to achieve the aim of zero waste liquid discharge.

The semicoke outlet of the dry distillation tank is provided with a sealed delivery valve, the outlet of the sealed delivery valve is connected with the inlet of a semicoke regenerator, steam or inert gas is injected between the semicoke inlet of the semicoke regenerator and an air outlet, and heated air is isolated from coal gas leaked from the sealed delivery valve to prevent explosion caused by mixing of the heated air and the coal gas.

The tar separation device comprises a water washing tower, an oil/water separator and an electric tar precipitator, coal gas flowing out of the retort enters the water washing tower for spray washing and cooling, tar is condensed and separated from water through the oil/water separator, sewage enters a sewage tank, tar is collected, and the coal gas flowing out of the spraying tower is supplied to users after tar and water are removed through the electric tar precipitator.

Advantageous effects

The system can gasify coal or solid fuel containing volatile matters to produce tar with greatly improved added value, and self-eliminates the semicoke without depending on external equipment to help consume the residual semicoke, and particularly can reduce the fuel cost and improve the power generation efficiency and peak regulation capacity aiming at low-melting-point ash or high-sulfur coal power generation.

Drawings

FIG. 1 is a schematic diagram of a system for producing gas and tar by comprehensive utilization of sensible heat of gasification, wherein a raw gas outlet of a circulating fluidized bed gasification furnace enters a dry distillation tank through a gas waste heat boiler, volatile coal gas produced by the dry distillation tank passes through a tar separation device, dry coal gas is separated out for users, tar is separately collected, sewage enters a sewage pool, the gas waste heat boiler is installed, or a return fan is also installed to extract part of the cooled and liquid-removed dry coal gas from the outlet of the tar separation device and return the extracted dry coal gas to an inlet of the dry distillation tank, the produced semicoke is sent to a circulating fluidized bed gasification furnace for air blowing to be mixed with coal to serve as fuel, a blower driven by a steam turbine is connected with the gasification furnace, water is pumped from the sewage pool and is sprayed into a blast pipeline to enter the gasification furnace together with air to produce gas, and.

FIG. 2 is a schematic diagram of a system for producing coal gas and tar by comprehensive utilization of sensible heat from gasification according to the present invention, in which an outlet of a blower driven by a steam turbine is connected to a char heat regenerator and then to an inlet of a circulating fluidized bed gasifier, wastewater pumped from a sewage tank is injected between an air inlet and an outlet of the char heat regenerator, char discharged from a retort enters the char heat regenerator through a sealed delivery valve, steam or inert gas is injected between the char inlet of the char heat regenerator and the air outlet thereof to isolate coal gas and air, the air blown from the blower and steam evaporated from the wastewater enter the gasifier together to produce coal gas, and the char discharged from the char heat regenerator is sent to the gasifier to serve as fuel.

FIG. 3 is a schematic diagram showing a system for producing coal gas and tar by comprehensively utilizing sensible heat of gasification, wherein a bypass coal outlet is arranged between a raw gas inlet and a raw gas outlet of a dry distillation tank or is divided into two compartments, one containing dry distillation coal and the other containing dry coal, the dry distillation coal is discharged from a semicoke outlet, the dry coal is discharged from a bypass outlet, and the discharged dry coal or solid fuel is mixed with the semicoke after dry distillation and is sent to a gasification furnace to be used as fuel.

FIG. 4 is a schematic diagram of a system for producing gas and tar by comprehensive utilization of sensible heat of gasification, wherein a gas pipeline at an outlet of a tar separation device is connected to a power generation boiler.

FIG. 5 is a schematic diagram showing a system for producing gas and tar by comprehensive utilization of sensible heat of gasification, wherein a gas pipeline at the outlet of a tar separation device is firstly connected with a desulfurization device and then connected with a gas turbine combined cycle unit through pressurization of a gas compressor to serve as fuel.

FIG. 6 is a schematic diagram of a system for producing gas and tar by comprehensive utilization of sensible heat from gasification, in which a gas pipeline at the outlet of a tar separation device is connected with a desulfurization device, and the gas after desulfurization and purification is connected with a boiler through a gas pipeline and is also connected with a gas turbine through a gas compressor to be used as fuel in a combined cycle.

FIG. 7 is a schematic diagram showing that in the system for producing gas and tar by comprehensively utilizing gasification sensible heat, steam produced by a gas waste heat boiler and a combined cycle waste heat boiler jointly drive a combined cycle steam turbine, and the connection mode is that steam outlets of the two waste heat boilers are connected in parallel and input into the steam turbine, or the two waste heat boilers are connected in series to heat feed water or steam and then supply the steam to the steam turbine.

FIG. 8 is a schematic diagram showing a system for producing gas and tar by comprehensively utilizing gasification sensible heat, wherein a tar separation device comprises a water washing tower, an oil/water separator and an electric tar precipitator, gas flowing out of a dry distillation tank enters the water washing tower for spray washing and cooling, tar is condensed and deposited together with water at the lower part of the water washing tower, water-containing tar captured by the electric tar precipitator is separated from a water-oil mixed solution of the water washing tower through the oil/water separator, sewage enters a sewage pool, tar is collected, and gas from the spraying tower is supplied to a user after tar and water are removed through the electric tar precipitator.

Detailed Description

The invention will be further illustrated with reference to the following specific examples. It is to be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Further, it should be understood that various changes or modifications of the present invention may be made by those skilled in the art after reading the teaching of the present invention, and such equivalents may fall within the scope of the present invention as defined in the appended claims. Note that:

"retort" means a vessel for retorting coal using sensible heat rather than combustion heat;

the tar separation device is a device capable of separating tar, water and coal gas;

by "sealed transfer valve" is meant a combination valve capable of transferring solids to block the flow of gas, typically a rotary seal valve.

The system for producing coal gas and tar by comprehensively utilizing gasification sensible heat as shown in figure 1:

the invention provides a system for producing coal gas and tar by comprehensively utilizing gasification sensible heat, wherein a raw coal gas outlet of a circulating fluidized bed gasification furnace 1 enters a dry distillation tank 2 through a coal gas waste heat boiler 4, the sensible heat of part of the raw coal gas is absorbed by heating water or steam by the coal gas waste heat boiler 2, the yield of semicoke is controlled by adjusting the sensible heat quantity entering the dry distillation tank 2, after the raw coal gas is mixed with a proper amount of coal, on the basis that the fuel heat value and volatile matter content of the gasification furnace 1 are higher than the lower limit, the balance between the dry distillation yield of semicoke and gasification consumption is achieved, volatile matter-containing coal gas produced by the dry distillation tank 2 passes through a tar separation device 3, the coal gas is separated for users, the tar is independently collected, sewage enters a sewage pool 6, a return fan 12 is also arranged at the same time of the coal gas waste heat boiler 4, a part of cooled and dewatered coal gas is extracted from the outlet of the tar separation device 3 and is injected, therefore, the components and the quality of the semicoke, the coal gas and the tar can be better controlled, the economic benefit of the product is optimal, the air blower 11 driven by the steam turbine 13 is connected, water is pumped from the sewage pool 6 and blown into air blast, the air blast and the water blast enter the gasification furnace 1 together to produce the coal gas, and steam required by the steam turbine 13 comes from the coal gas waste heat boiler 4.

As shown in fig. 2, the outlet of the blower 11 is connected to the carbocoal regenerator 5 and then to the inlet of the circulating fluidized bed gasifier 1:

the invention provides a system for producing coal gas and tar by comprehensively utilizing gasification sensible heat, wherein an outlet of an air blower 11 driven by a steam turbine 13 is firstly connected with a semicoke regenerator 5 and then connected with an inlet of a circulating fluidized bed gasification furnace 1, waste water pumped by a sewage tank 6 is sprayed between an air inlet and an outlet of the semicoke regenerator 5 to cool hot semicoke, the waste water is evaporated into steam, semicoke discharged from a dry distillation tank 2 enters the semicoke regenerator 5 through a sealed delivery valve 15, steam or inert gas is injected between the semicoke inlet of the semicoke regenerator 5 and the air outlet of the semicoke regenerator to isolate coal gas and air, the air blown from the air blower 11 and the steam after the evaporation of the waste water enter the gasification furnace 1 together to produce coal gas, and the semicoke after the temperature reduction is discharged from the semicoke regenerator 5 and is sent to the gasification furnace 1 to be used as fuel.

In the low-temperature section of the retort 2 shown in fig. 3, a part of coal or solid fuel containing volatile matters is heated and dried:

the invention provides a system for producing coal gas and tar by comprehensively utilizing gasification sensible heat, wherein naturally stored coal or solid fuel contains more or less certain moisture, the moisture can consume more heat during gasification combustion to reduce the gasification efficiency, the gasified coal and dry distilled coal are added into a dry distillation tank 2 together, the moisture in the coal or the solid fuel is evaporated by utilizing the sensible heat of the raw gas at the low temperature section of the dry distillation tank 2, a bypass coal outlet is arranged between the raw gas inlet and the outlet of the dry distillation tank 2 or divided into two compartments, one containing the dry distilled coal and the other containing the dry distilled coal, the dry distilled coal is discharged from a semicoke outlet, the dry coal is discharged from the bypass coal outlet, and the discharged dry coal or solid fuel and the semicoke after dry distillation are mixed and sent to a gasification furnace 1 to be used as fuel to improve the gasification efficiency.

As shown in fig. 4, the gas pipeline at the outlet of the tar separation device 3 is connected to a power generation boiler 16:

the invention provides a system for producing coal gas and tar by comprehensively utilizing gasification sensible heat, wherein a power generation boiler 16 has certain requirements on the impurity content of coal or other solid fuels, the heat exchange surface of the boiler 16 is coked due to overhigh content of ash with low melting point, a coal gas pipeline at the outlet of a tar separation device 3 is connected to the power generation boiler 16, the consumption of the solid fuels in the boiler 16 is reduced, the coal gas is replaced by coal gas after cooling, ash removal and liquid removal, the ash content in the flue gas is reduced, and the threat of coking of the boiler 16 is reduced.

The gas pipeline at the outlet of the tar separation device 3 is connected with the gas turbine 14 for combined circulation as shown in FIG. 5:

the invention provides a system for producing gas and tar by comprehensively utilizing gasification sensible heat, wherein a gas pipeline at the outlet of a tar separation device 3 is firstly connected with a desulfurization device 7 and then is connected with a gas turbine 16 combined cycle unit through a gas compressor 8 under pressure to be used as fuel, as the combined cycle efficiency power generation of a gas turbine 14 is obviously higher than the power generation of a steam boiler 16, the gas desulfurization treatment capacity is smaller than the flue gas desulfurization treatment capacity of the boiler 16, the product sulfur of the former has higher value than the gypsum of the latter, and when the gas can be used for power generation as well, the combined cycle efficiency of the gas turbine 14 is higher than the power generation efficiency of the boiler 16 and the investment is small. The outlet gas pipeline of the tar separation device 3 is connected with the boiler 16 and the gas turbine 14 for combined circulation as shown in FIG. 6:

the invention provides a system for producing coal gas and tar by comprehensively utilizing gasification sensible heat, wherein a coal gas pipeline at the outlet of a tar separation device 3 is connected with a desulfurization device 3, the desulfurized and purified coal gas is connected with a boiler 16 through a pipeline, and is connected with a gas turbine 14 through a gas compressor 8 in a pressurizing way to be used as fuel in a combined cycle manner, the coal gas is supplied to the gas turbine 14 to be started and run at full load when the load is high, the gas turbine 14 is stopped when the load is low, the coal gas is supplied to the boiler 16 to stabilize flame and burn at low load, under the condition that a gasification and dry distillation system keeps running at full load stably, the tar is produced to the maximum extent, the load regulation to a greater extent is realized, and the system is very suitable for the.

As shown in fig. 7, the combined cycle turbine 9 is driven by the steam produced by the gas exhaust-heat boiler 4 and the combined cycle exhaust-heat boiler 10:

the invention provides a system for producing gas and tar by comprehensively utilizing gasification sensible heat, wherein the gas temperature at the outlet of a circulating fluidized bed gasification furnace 1 is far higher than the inlet flue gas temperature of a combined cycle waste heat boiler 10, and a gas waste heat boiler 4 can produce steam with higher parameters than the combined cycle waste heat boiler 10 to drive a combined cycle turbine 9 with higher efficiency to generate electricity. The tar separator 3 shown in fig. 8:

the invention provides a system for producing coal gas and tar by comprehensively utilizing gasification sensible heat, wherein a tar separation device 3 comprises a water washing tower 31, an oil/water separator 32 and an electric tar precipitator 33, the coal gas flowing out of a dry distillation tank 2 enters the water washing tower 31 for spray washing and cooling, the tar is condensed and deposited at the lower part of the water washing tower 31 together with water, the water-containing tar captured by the electric tar precipitator 33 and the oil-water mixed liquid of the water washing tower 31 are separated by the oil/water separator 32, the sewage enters a sewage tank 6, the tar is collected, and the coal gas from the spraying tower 31 is subjected to tar and water removal by the electric tar precipitator 33 and then is used by a user.