Gradient utilization system for tail gas of coal gas

Abstract

The utility model discloses a gradient utilization system for tail gas of coal gas. The gradient utilization system comprises a hot blast stove heating system, a rotary kiln drying and heating system, a pulverized coal crushing and drying system, a power generation system and a coal gas diffusion system, branches of the hot blast stove heating system, the rotary kiln drying and heating system, the pulverized coal crushing and drying system, the power generation system and the gas diffusion system are arranged in parallel. And branches of the hot-blast stove heating system, the rotary kiln drying and heating system, the pulverized coal crushing and drying system, the power generation system and the gas diffusion system are all communicated with a clean gas main pipeline so as to receive gas tail gas conveyed at the upstream of the process. The system provided by the utility model is used for solving the problems in the prior art and solving the problems that in the prior art, tail gas of coal gas cannot be efficiently utilized, the tail gas is severely dispersed, so that energy is wasted, and the requirements of the existing process cannot be met.

Description

Technical Field

[0001] This utility model relates to the field of coal gas utilization technology, and in particular to a coal gas tail gas cascade utilization system. Background Technology

[0002] Steel enterprises generate large amounts of coal gas resources during their production processes, such as blast furnace gas, coke oven gas, and gas from other reactors. These gases have high calorific value and are important secondary energy sources. However, due to various reasons, steel plants suffer from low energy utilization efficiency, inadequate management, and outdated technology in their coal gas systems. The coal gas contains a large amount of harmful substances, and direct emission without treatment will cause serious environmental pollution. Coal gas contains not only sensible heat but also chemical heat such as CO and H2. With continuous technological advancements, the utilization of coal gas tail gas will become more efficient and diversified in the future. Full utilization of this gas will not only improve energy efficiency but also reduce environmental pollution, possessing significant economic and environmental implications and playing a positive role in achieving green production and promoting sustainable development.

[0003] Therefore, based on the above-mentioned technical problems, those skilled in the art urgently need to develop a cascade utilization system for coal gas tail gas. Utility Model Content

[0004] The purpose of this utility model is to provide a coal gas tail gas cascade utilization system. This system is used to solve the problems existing in the prior art, and solves the problems of inefficient utilization of coal gas tail gas and serious tail gas dispersion, which leads to energy waste and cannot meet the requirements of the existing process.

[0005] To achieve the above objectives, this utility model provides the following technical solution:

[0006] This utility model discloses a coal gas tail gas cascade utilization system, which connects to the upstream reactor of the process through a clean coal gas main pipeline to transport coal gas tail gas to the downstream system.

[0007] The cascade utilization system includes:

[0008] Hot blast furnace heating system, rotary kiln drying heating system, pulverized coal crushing and drying system, power generation system and gas venting system;

[0009] The branches of the hot blast stove heating system, rotary kiln drying heating system, pulverized coal crushing and drying system, power generation system and gas venting system are arranged in parallel, and the branches of the hot blast stove heating system, rotary kiln drying heating system, pulverized coal crushing and drying system, power generation system and gas venting system are all connected to the clean gas main pipeline to receive the gas tail gas transported from the upstream of the process.

[0010] The hot air furnace heating system is connected to the coal powder crushing and drying system through a waste gas branch and dries the coal powder in the coal powder crushing and drying system.

[0011] The coal gas exhaust that has not been treated by the hot blast stove heating system, rotary kiln drying heating system, pulverized coal crushing and drying system, and power generation system enters the coal gas venting system and is discharged to the outside through the chimney.

[0012] Furthermore, the main clean gas pipeline is equipped with a thermometer, a pressure gauge, a flow meter, a gas analyzer, and a pressure regulating valve assembly in sequence according to the process flow.

[0013] The clean coal gas main pipeline uses the coal gas analyzer to detect the CO and H2 content in the clean coal gas online.

[0014] The clean coal gas main pipeline monitors the temperature, pressure and flow rate of the internal gas through a thermometer, a pressure gauge and a flow meter, and regulates the flow rate through a pressure regulating valve group.

[0015] Furthermore, the hot blast furnace heating system includes:

[0016] Hot blast furnace heating system piping; and

[0017] A hot blast stove connected to the downstream end of the hot blast stove heating system pipeline, wherein combustion air is introduced into the hot blast stove through a combustion air pipeline;

[0018] The hot air furnace heating system pipeline is sequentially equipped with a first electric switch butterfly valve, an electric blind flange valve, a pressure gauge, a flow meter, a first pneumatic quick-cut butterfly valve, a first pneumatic regulating valve, a first manual valve, a starter burner, and a combustion valve according to the process flow.

[0019] Furthermore, the rotary kiln drying and heating system includes:

[0020] Rotary kiln drying and heating system piping; and

[0021] The rotary kiln is connected to the downstream end of the process of the rotary kiln drying and heating system pipeline. The input end of the rotary kiln receives coke oven gas and combustion air through the pipeline.

[0022] The rotary kiln drying and heating system pipeline is equipped with a first gas shut-off valve, a gas blind flange valve, a pressure gauge, a flow meter, a gas safety valve, and a gas flow regulating valve in sequence according to the process flow.

[0023] Furthermore, the pulverized coal crushing and drying system includes:

[0024] Piping for pulverized coal crushing and drying system; and

[0025] A horizontal flue gas furnace is connected to the downstream end of the coal powder crushing and drying system pipeline. The horizontal flue gas furnace is connected to the hot air furnace through the waste gas branch to receive the waste flue gas from the hot air furnace.

[0026] The coal powder crushing and drying system pipeline is sequentially equipped with a second electric switch butterfly valve, a blind valve, a pressure gauge, a flow meter, a flow regulating valve, a second pneumatic quick-cut butterfly valve, and a second manual valve according to the process flow, and the coal powder crushing and drying system pipeline is connected to the main burner of the horizontal flue gas furnace.

[0027] Furthermore, the exhaust gas branch is equipped with a hot air furnace exhaust gas shut-off valve, a hot air furnace exhaust gas flow regulating valve, an exhaust gas fan, a damper opening regulator, and a temperature gauge sequentially from the hot air furnace heating system side to the coal powder crushing and drying system side.

[0028] Furthermore, the power generation system includes:

[0029] Power generation system piping; and

[0030] A gas-fired boiler is connected to the downstream end of the power generation system pipeline, and a second gas shut-off valve is installed upstream of the gas-fired boiler.

[0031] Furthermore, the gas venting system includes:

[0032] Gas venting system piping; and

[0033] The flue gas induced draft fan, desulfurization tower and chimney are sequentially installed in the gas venting system pipeline according to the process flow.

[0034] The coal gas tail gas is desulfurized in the desulfurization tower and then discharged to the outside through the chimney.

[0035] Furthermore, the tail gas emission rate of the gas venting system is less than 5%.

[0036] In the above technical solution, the coal gas tail gas cascade utilization system provided by this utility model has the following beneficial effects:

[0037] To achieve tiered and full utilization of coal gas, the system of this utility model connects the main clean coal gas pipeline to a hot blast stove heating system, a rotary kiln drying heating system, a pulverized coal crushing and drying system, a power generation system, and a coal gas venting system. The flow rate of clean coal gas entering each system can be remotely controlled manually or intelligently, optimizing the coal gas scheduling strategy. By real-time monitoring and analysis of coal gas production, coal gas composition, and usage in each branch, the system can grasp the coal gas supply and demand balance, providing a basis for coal gas allocation and achieving efficient utilization of coal gas.

[0038] The system of this invention can not only make full use of the physical sensible heat of high-temperature coal gas, but also fully release the chemical heat of coal gas, which greatly reduces the energy consumption of the entire process and achieves the goal of energy saving and consumption reduction. Finally, the coal gas tail gas emission rate is controlled within 5%, significantly reducing pollutant emissions. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this utility model. For those skilled in the art, other drawings can be obtained based on these drawings.

[0040] Figure 1 This is a system flowchart of a coal gas tail gas cascade utilization system disclosed in an embodiment of this application.

[0041] Explanation of reference numerals in the attached figures:

[0042] 1. Thermometer; 2. Pressure gauge; 3. Flow meter; 4. Gas analyzer; 5. Pressure regulating valve assembly; 6. First electrically operated butterfly valve; 7. First electrically operated blind valve; 8. First pneumatic quick-cut butterfly valve; 9. First pneumatic regulating valve; 10. First manual valve; 11. Burner starter; 12. Combustion valve; 13. Hot blast stove; 14. Combustion air; 15. First gas shut-off valve; 16. Gas blind valve; 17. Gas safety valve; 18. Gas flow regulating valve; 19. Coke oven gas 20. Rotary kiln; 21. Second electric switch butterfly valve; 22. Blind plate valve; 23. Flow regulating valve; 24. Second pneumatic quick-cut butterfly valve; 25. Second manual valve; 26. Main burner; 27. Horizontal flue gas furnace; 28. Hot blast stove waste flue gas; 29. ​​Hot blast stove waste flue gas shut-off valve; 30. Hot blast stove waste flue gas flow regulating valve; 31. Flue gas induced draft fan; 32. Damper opening adjustment; 33. Second gas shut-off valve; 34. Gas boiler; 35. Desulfurization tower; 36. Chimney. Detailed Implementation

[0043] To enable those skilled in the art to better understand the technical solution of this utility model, the present utility model will be further described in detail below with reference to the accompanying drawings.

[0044] See Figure 1 As shown;

[0045] This embodiment discloses a coal gas tail gas cascade utilization system. The cascade utilization system is connected to the upstream reactor of the process through a clean coal gas main pipeline to transport coal gas tail gas to the downstream system.

[0046] The cascade utilization system includes:

[0047] Hot blast furnace heating system, rotary kiln drying heating system, pulverized coal crushing and drying system, power generation system and gas venting system;

[0048] The branches of the hot blast stove heating system, rotary kiln drying heating system, pulverized coal crushing and drying system, power generation system and gas venting system are arranged in parallel, and the branches of the hot blast stove heating system, rotary kiln drying heating system, pulverized coal crushing and drying system, power generation system and gas venting system are all connected to the main clean gas pipeline to receive the tail gas transported from the upstream of the process.

[0049] The hot air furnace heating system is connected to the pulverized coal crushing and drying system through the exhaust gas branch and dries the pulverized coal in the pulverized coal crushing and drying system.

[0050] The coal gas exhaust that has not been treated by the hot blast stove heating system, rotary kiln drying heating system, pulverized coal crushing and drying system, and power generation system enters the coal gas venting system and is discharged to the outside through the chimney.

[0051] Specifically, this embodiment discloses a novel cascade utilization system for coal gas tail gas. Generally, clean coal gas refers to the coal gas tail gas generated in the reactor during normal production, which has a low dust content after being treated by one or more combined dust removal methods such as gravity dust collection, cyclone dust collection, and bag filter dust collection. The dust content of the clean coal gas is generally controlled at 100 mg / m³. 3 Even below 10 mg / m 3 The temperature of the clean coal gas is ≤200℃; the composition of the clean coal gas generally includes CO, CO2, H2, H2O, N2, etc., with CO content of 15-25%, CO2 content of 15-25%, N2 content of 35-50%, H2 content of 0-10%, and H2O content of 0-10%.

[0052] For the aforementioned purified coal gas, the system in this embodiment includes five systems downstream of the main purified coal gas pipeline: a hot blast stove heating system, a rotary kiln drying and heating system, a pulverized coal crushing and drying system, a power generation system, and a coal gas venting system. The coal gas tail gas cascade utilization control system in this embodiment is a remote online control system, allowing for remote manual or intelligent control of these five systems.

[0053] Preferably, in this embodiment, the main pipeline for clean coal gas is equipped with a thermometer 1, a pressure gauge 2, a flow meter 3, a coal gas analyzer 4, and a pressure regulating valve group 5 in sequence according to the process flow; wherein, the main pipeline for clean coal gas uses the coal gas analyzer 4 to detect the CO and H2 content in the clean coal gas online;

[0054] Furthermore, in this embodiment, the temperature, pressure, and flow rate of the internal gas are monitored via thermometer 1, pressure gauge 2, and flow meter 3 through the main clean gas pipeline, and the flow rate is regulated via pressure regulating valve assembly 5. This embodiment provides usage parameters to downstream users through the data monitored by instruments on the main clean gas pipeline.

[0055] Preferably, the hot air furnace heating system of this embodiment includes:

[0056] Hot blast furnace heating system piping; and

[0057] Hot blast stove 13 is connected to the downstream end of the hot blast stove heating system pipeline. Combustion air 14 is introduced into hot blast stove 13 through combustion air pipeline.

[0058] The hot air furnace heating system pipeline is equipped with the following components in sequence according to the process flow: first electric switch butterfly valve 6, electric blind valve 7, pressure gauge 2, flow meter 3, first pneumatic quick-cut butterfly valve 8, first pneumatic regulating valve 9, first manual valve 10, start-up burner 11, and combustion valve 12.

[0059] First, the clean coal gas enters the hot blast stove heating system and mixes and burns with coke oven gas 19 and combustion air 14 to raise the temperature of the hot blast stove 13. The exhaust gas temperature is controlled by adjusting the coal gas flow rate, and the combustion is controlled by adjusting the combustion air 14 flow rate. The generated high-temperature hot air (1100℃-1200℃) is then sent into the reactor. The exhaust gas generated by the hot blast stove 13 enters the coal powder crushing and drying system to dry the coal powder.

[0060] Preferably, the rotary kiln drying and heating system of this embodiment includes:

[0061] Rotary kiln drying and heating system piping; and

[0062] The rotary kiln 20 is connected to the downstream end of the rotary kiln drying and heating system pipeline. The input end of the rotary kiln 20 receives coke oven gas 19 and combustion air 14 through the pipeline.

[0063] The rotary kiln drying and heating system pipeline is equipped with the following components in sequence according to the process flow: first gas shut-off valve 15, gas blind valve 16, pressure gauge 2, flow meter 3, gas safety valve 17, and gas flow regulating valve 18.

[0064] Secondly, the tail gas from the coal gas is used by the rotary kiln drying and heating system of this embodiment. The clean coal gas enters the rotary kiln drying and heating system and mixes and burns with the coke oven gas 19 and the combustion air 14. The gas flow rate and the fuel gas ratio are adjusted by controlling the clean coal gas flow regulating valve so that the temperature of each section in the rotary kiln 20 is within a reasonable range, and the wet iron ore powder is dried and preheated, maintaining the temperature of the iron ore powder exiting the kiln at 300℃-500℃.

[0065] Preferably, the coal powder crushing and drying system of this embodiment includes:

[0066] Piping for pulverized coal crushing and drying system; and

[0067] A horizontal flue gas furnace 27 is connected to the downstream end of the coal powder crushing and drying system pipeline. The horizontal flue gas furnace 27 is connected to the hot blast furnace 13 through a waste gas branch to receive the waste flue gas from the hot blast furnace 13.

[0068] The coal powder crushing and drying system pipeline is equipped with a second electric switch butterfly valve 21, a blind plate valve 22, a pressure gauge 2, a flow meter 3, a flow regulating valve 23, a second pneumatic quick-cut butterfly valve 24, and a second manual valve 25 in sequence according to the process flow, and the coal powder crushing and drying system pipeline is connected to the main burner 26 of the horizontal flue gas furnace.

[0069] In this embodiment, the coal gas tail gas is reused in the coal powder crushing and drying system. The clean coal gas is controlled by the above-mentioned electrical components for flow control, safety control, remote control, and local control. The clean coal gas is mixed and burned with coke oven gas 19 and combustion air 14. By controlling the clean coal gas flow regulating valve, the gas flow rate and combustion ratio are adjusted, which can stably control the air-fuel mixture and the combustion temperature (800℃-1000℃) of the horizontal flue gas furnace 27. The waste flue gas introduced from the hot air furnace 13 can also adjust the oxygen content in the flue gas after combustion, increase the flue gas volume, and reduce the flue gas temperature to generate high-temperature flue gas (300℃-500℃) for raw coal drying, so that the moisture content of the dry coal powder is less than 2%.

[0070] Preferably, in this embodiment, the exhaust gas branch is provided with a hot air furnace exhaust gas shut-off valve 29, a hot air furnace exhaust gas flow regulating valve 30, an exhaust gas fan 31, a damper opening regulator 32, and a thermometer 1 in sequence from the hot air furnace heating system side to the coal powder crushing and drying system side.

[0071] Preferably, the power generation system of this embodiment includes a power generation system pipeline; and a gas boiler 34 connected to the downstream end of the power generation system pipeline, wherein a second gas shut-off valve 33 is provided upstream of the gas boiler 34.

[0072] In this embodiment, the coal gas tail gas is finally used by the power generation system. The clean coal gas is burned with combustion air in the combustion boiler 34. When the calorific value of the coal gas fluctuates, an appropriate amount of coke oven gas is added to maintain stable combustion and stable power generation.

[0073] Preferably, the gas venting system of this embodiment includes a gas venting system pipeline; and a flue gas induced draft fan 31, a desulfurization tower 35, and a chimney 36, which are sequentially arranged in the gas venting system pipeline according to the process flow; the gas tail gas is discharged to the outside through the chimney 36 after being desulfurized by the desulfurization tower 35. The gas tail gas venting rate of the gas venting system of this embodiment is less than 5%.

[0074] In the above technical solution, the coal gas tail gas cascade utilization system provided by this utility model has the following beneficial effects:

[0075] To achieve tiered and full utilization of coal gas, the system of this utility model connects the main clean coal gas pipeline to a hot blast stove heating system, a rotary kiln drying heating system, a pulverized coal crushing and drying system, a power generation system, and a coal gas venting system. The flow rate of clean coal gas entering each system can be remotely controlled manually or intelligently, optimizing the coal gas scheduling strategy. By real-time monitoring and analysis of coal gas production, coal gas composition, and usage in each branch, the system can grasp the coal gas supply and demand balance, providing a basis for coal gas allocation and achieving efficient utilization of coal gas.

[0076] The system of this invention can not only make full use of the physical sensible heat of high-temperature coal gas, but also fully release the chemical heat of coal gas, which greatly reduces the energy consumption of the entire process and achieves the goal of energy saving and consumption reduction. Finally, the coal gas tail gas emission rate is controlled within 5%, significantly reducing pollutant emissions.

[0077] The foregoing description only illustrates certain exemplary embodiments of the present invention. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A coal gas tail gas cascade utilization system, characterized in that, The cascade utilization system is communicated with a reaction furnace upstream in a process through a main clean gas pipeline to deliver tail gas to a system downstream in the process; The cascade utilization system comprises: a hot blast stove heating system, a rotary kiln drying heating system, a pulverized coal crushing and drying system, a power generation system and a coal gas emission system; Branches of the hot blast stove heating system, the rotary kiln drying heating system, the pulverized coal crushing and drying system, the power generation system and the coal gas emission system are arranged in parallel, and the branches of the hot blast stove heating system, the rotary kiln drying heating system, the pulverized coal crushing and drying system, the power generation system and the coal gas emission system are communicated with the main clean gas pipeline to receive the tail gas delivered from the upstream in the process; The hot blast stove heating system is communicated with the pulverized coal crushing and drying system through a waste gas branch and dries the pulverized coal of the pulverized coal crushing and drying system; The tail gas that has not been treated by the hot blast stove heating system, the rotary kiln drying heating system, the pulverized coal crushing and drying system and the power generation system enters the coal gas emission system and is discharged to the outside through a chimney.

2. The coal gas tail gas cascade utilization system according to claim 1, characterized in that, A temperature gauge (1), a pressure gauge (2), a flow meter (3), a coal gas analyzer (4) and a pressure regulating valve group (5) are sequentially installed on the main clean gas pipeline according to a process flow; The main clean gas pipeline detects the CO and H2 contents in the clean gas on line through the coal gas analyzer (4); The main clean gas pipeline monitors the temperature, pressure and flow of the internal gas through the temperature gauge (1), the pressure gauge (2) and the flow meter (3) and adjusts the flow through the pressure regulating valve group (5).

3. The coal gas tail gas cascade utilization system according to claim 1, characterized in that, The hot blast stove heating system comprises: a hot blast stove heating system pipeline; and a hot blast stove (13) connected to a process downstream end of the hot blast stove heating system pipeline, the hot blast stove (13) introducing combustion air (14) into the hot blast stove (13) through a combustion air pipeline; A first electrically-driven on-off butterfly valve (6), an electrically-driven blind plate valve (7), a pressure gauge (2), a flow meter (3), a first pneumatic quick-cut butterfly valve (8), a first pneumatic regulating valve (9), a first hand valve (10), a start-up burner (11) and a combustion valve (12) are sequentially arranged on the hot blast stove heating system pipeline according to a process flow.

4. The coal gas tail gas cascade utilization system according to claim 1, characterized in that, The rotary kiln drying heating system comprises: a rotary kiln drying heating system pipeline; and a rotary kiln (20) connected to a process downstream end of the rotary kiln drying heating system pipeline, an input end of the rotary kiln (20) receiving coke oven gas (19) and combustion air (14) through a pipeline; A first coal gas cut-off valve (15), a coal gas blind plate valve (16), a pressure gauge (2), a flow meter (3), a coal gas safety valve (17) and a coal gas flow regulating valve (18) are sequentially arranged on the rotary kiln drying heating system pipeline according to a process flow.

5. The coal gas tail gas cascade utilization system according to claim 3, characterized in that, The pulverized coal crushing and drying system comprises: a pulverized coal crushing and drying system pipeline; and a horizontal flue gas furnace (27) connected to a process downstream end of the pulverized coal crushing and drying system pipeline, the horizontal flue gas furnace (27) being communicated with the hot blast stove (13) through the waste gas branch to receive hot blast stove waste flue gas delivered by the hot blast stove (13); The coal powder crushing drying system pipeline is sequentially provided with a second electric switch butterfly valve (21), a blind plate valve (22), a pressure gauge (2), a flow meter (3), a flow regulating valve (23), a second pneumatic quick cut butterfly valve (24), and a second manual valve (25) according to the technological process, and the coal powder crushing drying system pipeline is connected with the main burner (26) of the horizontal flue gas furnace (27).

6. The coal gas tail gas cascade utilization system according to claim 1 or 3 or 5, characterized in that, The waste gas branch is sequentially provided with a hot blast furnace waste flue gas cut-off valve (29), a hot blast furnace waste flue gas flow regulating valve (30), a flue gas induced draft fan (31), a damper opening degree regulator (32), and a temperature gauge (1) from the hot blast furnace heating system side to the coal powder crushing drying system side.

7. The coal gas tail gas cascade utilization system according to claim 1, characterized in that, The power generation system comprises: a power generation system pipeline; and a gas-fired boiler (34) connected to a downstream end of the power generation system pipeline, and a second gas cut-off valve (33) arranged upstream of the gas-fired boiler (34) in the process.

8. The coal gas tail gas cascade utilization system according to claim 1, characterized in that, The coal gas diffusion system comprises: a coal gas diffusion system pipeline; and a flue gas induced draft fan (31), a desulfurization tower (35), and a chimney (36) sequentially arranged in the coal gas diffusion system pipeline according to the technological process; coal gas tail gas is discharged to the outside by the chimney (36) after flue gas desulfurization by the desulfurization tower (35).

9. The coal gas tail gas cascade utilization system according to claim 8, characterized in that, The coal gas diffusion system has a coal gas tail gas diffusion rate of less than 5%.

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