A tail gas ultra-clean emission CCPP power generation system

Abstract

The application discloses a kind of tail gas ultra-clean emission's CCPP power generation system, it is related to steel enterprise by-product gas power generation technical field, to solve the problem that existing CCPP environmental protection facilities needs to be improved;The coal gas system of the present application includes coal gas desulfurization device, coal gas dust collector and coal presser communicated in sequence, air system includes air filter and air compressor communicated in sequence, coal presser and air compressor supply compressed coal gas and air to combustor, coal gas and air are burned in combustor to produce high-temperature flue gas, drive gas turbine to work and enter waste heat boiler, multiple heat exchange surfaces and flue gas denitration device are arranged in waste heat boiler, and flue gas is discharged from chimney after denitration;Water is heated into steam in waste heat boiler, enters steam turbine to work, then is condensed into condensate water after condenser condensation, and returns waste heat boiler by condensate water pump;The present application is simple and reasonable in structure, from coal gas side, air side, flue gas side three aspects, beneficial to realize the ultra-low emission of CCPP generator set tail gas.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of steel enterprises by-product gas power generation, in particular to a CCPP power generation system with tail gas ultra-clean emission. BACKGROUND

[0002] A large amount of by-product gas, including blast furnace gas, converter gas, coke oven gas, etc., is generated in the smelting process of a steel enterprise. In addition to the consumption of each smelting process, there is still a part of the gas surplus, especially the blast furnace gas. In order to efficiently utilize the remaining gas, a gas power generation unit is generally constructed in the steel plant. Among them, CCPP (gas-steam combined cycle power generation) has better comprehensive benefits because its efficiency is higher than that of the conventional BTG (boiler-turbine power generation) route, which is conducive to the steel plant to improve the self-generation rate and reduce carbon emissions.

[0003] At present, CCPP has been applied in many steel plants in China and has achieved good operation effect. However, with the improvement of environmental protection emission standards, the conventional CCPP configuration cannot meet the increasingly stringent air pollutant emission indicators, so it is necessary to improve the environmental protection facilities, which plays a very important role in the popularization and application of CCPP technology. SUMMARY

[0004] The purpose of the present application is to provide a CCPP power generation system with tail gas ultra-clean emission to solve the problem that the existing CCPP environmental protection facilities need to be improved.

[0005] To achieve the above purpose, the present application provides the following technical scheme: a CCPP power generation system with tail gas ultra-clean emission:

[0006] The system comprises a gas system, an air system and a flue gas system. The gas system comprises a gas desulfurization device, a gas dust remover and a coal presser which are sequentially connected. The air system comprises an air filter and a gas compressor which are sequentially connected. The gas system and the air system supply gas to the combustor of the flue gas system for combustion. The generated high-temperature and high-pressure flue gas enters the waste heat boiler after doing work by the gas turbine. The flue gas is discharged from the chimney after being cooled by the waste heat boiler.

[0007] The waste heat boiler uses water as the heat exchange medium. The steam discharged from the waste heat boiler returns to the water inlet of the waste heat boiler through the steam turbine, the condenser and the condensate pump.

[0008] Preferably, the gas system further comprises a gas backflow cooler. The gas inlet of the gas backflow cooler is connected to the gas outlet end of the coal presser. The gas outlet of the gas backflow cooler is connected to the gas pipeline between the gas desulfurization device and the gas dust remover. When the gas turbine is reduced or shedded, the gas backflow cooler rapidly cools the gas at the outlet of the coal presser to prevent overpressure release or even safety accidents in the gas system, and sends the gas back to the gas dust remover for recycling.

[0009] Preferably, the combustor adopts a low-nitrogen combustor for controlling the concentration of nitrogen oxides in the flue gas generated by the combustion chamber.

[0010] Preferably, the gas outlets of the coal press and the air compressor are respectively connected to the gas inlet and the air inlet of the combustor through pipelines.

[0011] Preferably, a flue gas denitration device is arranged in the waste heat boiler, and the flue gas denitration device adopts an SCR (Selective Catalytic Reduction) process, and the reducing agent is ammonia water or urea.

[0012] Preferably, the system further comprises a first generator, and the gas turbine drives the first generator to generate electricity.

[0013] Preferably, the rotating shafts of the gas turbine, the first generator, the coal press and the air compressor are drivingly connected.

[0014] Preferably, the system further comprises a second generator, and the steam turbine drives the second generator to generate electricity.

[0015] Preferably, the coal gas desulfurization device adopts a dry process for blast furnace gas and converter gas, and adopts a wet process for coke oven gas.

[0016] Preferably, the coal gas dust remover adopts a wet electric dust remover to reduce the dust content in the coal gas to 1 mg / m 3 or less.

[0017] Compared with the prior art, the present application has the following beneficial effects:

[0018] The CCPP power generation system with tail gas ultra-clean emission has a simple and reasonable structure, and jointly starts from three aspects of the coal gas side, the air side and the flue gas side, which is beneficial to realize ultra-low emission (SO2, NO x , dust) of the tail gas of the CCPP generator set, realizes coal gas desulfurization through the coal gas desulfurization device, realizes coal gas dust removal through the coal gas dust remover, thereby completing the sulfide and dust purification treatment of the fuel side, reduces the dust content in the air through the air filter, completes the dust purification treatment of the air side, realizes the source inhibition of nitrogen oxides through the low-nitrogen combustor, realizes flue gas denitration through the flue gas denitration device, and completes the nitrogen oxide purification treatment of the flue gas side, so that the CCPP power generation system can better adapt to the growing environmental protection needs.

[0019] In addition, compared with flue gas desulfurization at the tail of the gas turbine at the rear end, the coal gas desulfurization at the front end of the CCPP can reduce the adverse effects of flue gas desulfurization on the back pressure of the gas turbine, including economic impact and impact on stable operation of the unit, and the advantage of the coal gas desulfurization at the front end of the CCPP is more obvious, especially in the case of narrow space and disorderly layout of the tail flue. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 The structural connection relationship of the present application is shown in the schematic diagram.

[0021] In the figure: 1, coal gas desulfurization device; 2, coal gas dust remover; 3, coal press; 4, combustor; 5, gas turbine; 6, air filter; 7, air compressor; 8, waste heat boiler; 9, chimney; 10, flue gas denitration device; 11, coal gas backflow cooler; 12, generator 1; 13, steam turbine; 14, generator 2; 15, condenser; 16, condensate pump. DETAILED DESCRIPTION

[0022] Reference Figure 1 A CCPP power generation system with tail gas ultra-clean emission, comprising a coal gas system, an air system and a flue gas system:

[0023] The coal gas system comprises a coal gas desulfurization device 1, a coal gas dust remover 2 and a coal press 3 connected in sequence, wherein the coal gas desulfurization device 1 is used to purify the coal gas by removing organic sulfur and inorganic sulfur in the coal gas; the coal gas dust remover 2 is used to purify the coal gas by removing dust particles in the coal gas; and the coal press 3 is used to compress the coal gas to a certain pressure and temperature, and finally send the coal gas into the combustor;

[0024] In a more preferred embodiment, the coal gas system further comprises a coal gas backflow cooler 11, the inlet of which is connected to the outlet of the coal press 3, and the outlet is connected to the coal gas pipeline between the coal gas desulfurization device 1 and the coal gas dust remover 2; when the gas turbine is reduced or unloaded, the coal gas backflow cooler 11 is used to quickly cool the coal gas at the outlet of the coal press 3 to prevent overpressure release or even safety accidents in the coal gas system, and the cooled coal gas is sent to the coal gas dust remover 2 for recycling.

[0025] The air system comprises an air filter 6 and an air compressor 7 connected in sequence, and the air inlet of the air filter 6 is connected to the atmosphere;

[0026] The coal gas system and the air system supply gas to the combustor 4 of the flue gas system for combustion, specifically, the outlets of the coal press 3 and the air compressor 7 are respectively connected to the coal gas inlet and the air inlet of the combustor 4 through pipelines, the combustor 4 can be further preferably a low-nitrogen combustor, which can control the concentration of nitrogen oxides in the flue gas generated in the combustion chamber at a low level; the flue gas after combustion is introduced into the waste heat boiler 8 through the gas turbine 5, and the waste heat boiler 8 is provided with a flue gas denitration device 10, which can adopt the SCR selective catalytic reduction process, and the reducing agent can be further preferably ammonia water or urea; the flue gas after denitration is discharged from the chimney 9;

[0027] The waste heat boiler 8 uses water as the heat exchange medium, and the steam discharged therefrom is returned to the water inlet of the waste heat boiler 8 through the steam turbine 13, the condenser 15 and the condensate pump 16.

[0028] In addition to the coal gas system, the air system and the flue gas system, the CCPP power generation system of course also includes a generator, in the present application, the system can adopt the following form: the system further includes a generator 12, the gas turbine 5 drives the generator 12 to generate electricity, and further preferably, the rotating shafts of the gas turbine 5, the generator 12, the coal press 3 and the air compressor 7 are drivingly connected, and the gas turbine 5, the coal press 3 and the air compressor 7 jointly drive the generator 12 to generate electricity, and in addition, the above system can also include a generator 14, the steam turbine 13 drives the generator 14 to generate electricity.

[0029] In a preferred embodiment, the coal gas desulfurization device adopts a dry process for blast furnace gas and converter gas, and reduces the total sulfur content in the coal gas to 20mg / m 3 In the above, a wet process is adopted for coke oven gas, and the total sulfur content in the coal gas is reduced to 50mg / m 3 In the above, a wet process is adopted for coke oven gas, and the total sulfur content in the coal gas is reduced to 50mg / m 3 In the above, a wet process is adopted for coke oven gas, and the total sulfur content in the coal gas is reduced to 50mg / m 3 In the above, a wet process is adopted for coke oven gas, and the total sulfur content in the coal gas is reduced to 50mg / m

[0030] The above is only a preferred embodiment of the present application, but the protection scope of the present application is not limited to this, any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be defined by the protection scope of the claims.

[0031] The parts not described in the present application are the known technology of the person skilled in the art.

Claims

1. A CCPP power generation system with ultra-clean tail gas emissions, characterized by: The invention comprises a gas system, an air system and a flue gas system, wherein the gas system comprises a gas desulfurization device (1), a gas dust collector (2) and a coal compressor (3) which are connected in sequence, and the air system comprises an air filter (6) and a compressor (7) which are connected in sequence. The gas system and the air system supply gas to a burner (4) of the flue gas system for combustion, and the generated high-temperature and high-pressure flue gas enters a waste heat boiler (8) after being worked by a gas turbine (5), and is discharged from a chimney (9) after being cooled by the waste heat boiler. The waste heat boiler (8) uses water as a heat exchange medium, and the discharged steam passes through the steam turbine (13), the condenser (15) and the condensate pump (16) and returns to the water inlet of the waste heat boiler (8); The coal gas system further comprises a coal gas reflux cooler (11), the air inlet of which is connected to the gas outlet of the coal compressor (3), and the gas outlet of the coal gas reflux cooler (11) is connected to the coal gas pipeline between the coal gas desulfurization device (1) and the coal gas dust collector (2); A flue gas denitrification device (10) is provided in the waste heat boiler, wherein the flue gas denitrification device (10) adopts an SCR selective catalytic reduction process, and the reducing agent is ammonia water or urea; The coal gas desulfurization device adopts a dry process for blast furnace gas and converter gas, and adopts a wet process for coke oven gas.

2. The CCPP power generation system with ultra-clean tail gas emissions according to claim 1, characterized in that: The burner (4) is a low-nitrogen burner, which is used to control the nitrogen oxide concentration of the flue gas generated in the combustion chamber.

3. The CCPP power generation system with ultra-clean exhaust emissions according to claim 1, characterized in that: The gas outlets of the coal compressor (3) and the gas compressor (7) are connected to the gas inlet and air inlet of the burner (4) through pipelines, respectively.

4. The CCPP power generation system with ultra-clean tail gas emissions according to claim 1, characterized in that: The system also includes a generator (12), and the gas turbine (5) drives the generator (12) to generate electricity.

5. The CCPP power generation system with ultra-clean exhaust emissions according to claim 4, characterized in that: The gas turbine (5), generator 1 (12), coal compressor (3) and compressor (7) are connected by rotating shafts.

6. The CCPP power generation system with ultra-clean exhaust emissions according to claim 1, characterized in that: The system also includes a second generator (14), and the steam turbine (13) drives the second generator (14) to generate electricity.

7. The CCPP power generation system with ultra-clean tail gas emissions according to claim 1, characterized in that: The coal gas dust collector adopts a wet electrostatic dust collector.

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