VOCs gas treatment system for coal gas purification area and tar deep processing area

Abstract

The invention belongs to the technical field of coking industry, and relates to a VOCs gas treatment system for a coal gas purification area and a tar deep processing area. A first sealable tank group (1), close to a coke oven gas blower, in a gas purification area comprises a plurality of sealable tanks, and each sealable tank of the first sealable tank group (1) is provided with a tank top safety device, a nitrogen pressure stabilizing device, a first VOCs gas collecting header pipe (2), an anti-explosion fire-retardant breather valve, an anti-explosion fire barrier, an explosion venting valve and a safety interlocking switching device. Each sealable tank of the first sealable tank group (1) is communicated with a first VOCs gas collecting header pipe (2) through a first branch pipe (3), and the first VOCs gas collecting header pipe (2) is communicated with a negative pressure pipeline (4) in front of a primary cooler of a coke oven gas system. The VOCs gas treatment system for the coal gas purification area and the tar deep processing area is simple in structure, gases in different tanks are treated in groups, the treatment effect is effectively improved, and the treatment cost is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of coking industry, and more specifically, relates to a VOCs gas treatment system in a coal gas purification area and a tar deep processing area. Background Art

[0002] The coking industry produces a wide variety of VOCs, with varying properties and sources. Based on their characteristics, treatment methods vary. Commonly used methods include absorption, adsorption, condensation recovery, combustion, and the introduction of negative pressure gas systems.

[0003] The principle of the absorption method is: select a liquid absorbent with low volatility, and select a suitable absorbent according to the type of gas to be treated. Commonly used absorbents include water, washing oil, acid and alkali, etc., which have a high affinity with the absorbed components. After absorption saturation, they are heated, desorbed, and cooled before being reused. Features: Suitable for tail gas with large gas volume, low temperature and low concentration. Advantages: Different absorbents can be used, and the scope of application is wide. Disadvantages: Complex equipment and large investment. Some indicators cannot meet the new environmental protection standards after treatment using this method alone;

[0004] The principle of the adsorption method is as follows: The adsorption method is divided into: 1) Direct adsorption method: Organic gas passes directly through activated carbon, which can achieve a purification rate of 95%. The equipment is simple, the investment is small, and the operation is convenient. However, the adsorption capacity of activated carbon is only about 40%, so the activated carbon needs to be replaced frequently. It is used in situations where the concentration is low and the pollutants do not need to be recovered. b) Adsorption recovery method: Organic gas is adsorbed by activated carbon. After the activated carbon is saturated, it is desorbed and regenerated with hot air or water vapor. The desorbed gas is condensed and recovered through a heat exchanger. The characteristics are: Advantages: High treatment efficiency, Disadvantages: Complex equipment, large investment, suitable for a narrow range of gases, such as simple organic compounds with a relatively simple composition and good volatility such as benzene. In addition, the activated carbon after adsorption is classified as hazardous solid waste and needs to be handled by a waste recycling company.

[0005] The condensation recovery method works by directly condensing VOCs or concentrating them through adsorption, then separating and recovering the valuable organic compounds in the condensate. Advantages include suitability for treating VOCs with a relatively simple composition, high concentration, low temperature, and low air volume. Disadvantages include high investment, energy consumption, and operating costs.

[0006] The principle of the combustion method is: The combustion method is divided into: 1) Regenerative combustion method: using a regenerative flue gas waste heat recovery device, alternately switching air or exhaust gas and flue gas, so that it flows through the heat storage body, which can recover the sensible heat of high-temperature flue gas to the greatest extent, and the exhaust temperature can be reduced to below 180°C. It is suitable for the treatment of low-concentration, large-volume organic tail gas. 2) Direct combustion method: using auxiliary fuels such as gas or fuel oil to burn combustible harmful gases directly. Such as: torches, non-catalytic combustion furnaces, etc. The characteristics are: this method has a simple process, can effectively solve organic waste gas pollution, and is one of the effective "end of the pipe technology". However, this method has high energy consumption and high operating costs.

[0007] In the existing technology, (1) problems exist in the gas purification area: 1) The storage tanks in the gas purification area do not have a relatively independent pressure balance system and pressure relief safety device, and the risk of the tanks being sucked out and expanded is high. 2) The existing VOCs collection pipelines do not have oxygen content detection and emergency safety shut-off systems, which can easily cause air to enter the coke oven gas purification system, affecting gas safety. 3) The media in the collection pipes of various devices in the existing VOCs collection pipelines are complex (benzene, H2S, CO, ammonium sulfate, NH3, etc.), and the original carbon steel material is prone to corrosion and leakage. 4) The existing VOCs collection pipelines do not have reasonable purge means, and naphthalene and salts carried in the exhaust gas are easy to clog the pipelines. At present, some pipelines are unusable due to blockage, resulting in the tanks being directly connected to the atmosphere. 5) The existing VOCs collection pipelines fail to take into account intermittent VOC emission equipment such as underground vent tanks. (2) Problems in the tar deep processing area: Most tanks are equipped with breathing valves, but no nitrogen seals or emergency pressure relief equipment. The pressure in the tank is mainly regulated by the breathing valve to let in air and exhaust gas. When the pressure in the tank changes drastically or the breathing valve is blocked, there is a risk of tank expansion and deflation, which poses a safety hazard. Most tanks are not nitrogen sealed. When the pressure in the tank drops, air is inhaled through the breathing valve to balance the pressure. The inhaled air and the organic matter volatilized in the tank easily form an explosive mixed gas. When encountering factors such as static electricity, it is easy to cause a deflagration, posing a safety risk. There are no reliable safety measures before the existing VOCs gas collection pipeline enters the torch, and it cannot effectively avoid backfire, posing a safety risk. The existing waste gas incineration device in the tar deep processing area is not a dedicated VOCs gas incineration environmental protection device. The VOCs gas is not fully incinerated, the incineration efficiency is low, and it can no longer meet the latest environmental protection requirements. In addition, there is no heat energy utilization unit, and the consumption of combustion-supporting fuel is large.

[0008] In the prior art, there is a technology named "A comprehensive utilization process of coke oven gas through methanol synthesis gasoline, co-production of liquefied natural gas and tar deep processing" and the publication (announcement) number is "CN1 05062590B". The comprehensive utilization process of coke oven gas through methanol synthesis gasoline, co-production of liquefied natural gas and tar deep processing of this technology is that the raw coal is converted into coke, tar and coke oven gas in a coke oven, the coke oven gas is purified for methanol synthesis, the vent gas is cryogenically separated to produce LNG, the crude methanol liquid phase after purification is subjected to synthetic oil reaction, and LPG and gasoline products are obtained after separation, and the tar is hydrogenated and hydrorefined to obtain gasoline, diesel and heavy oil products. The present invention has the advantages of high utilization rate, simple process, reasonable product structure and low environmental pollution. However, this technology does not involve the technical problems and technical solutions of the present application. Summary of the Invention

[0009] The technical problem to be solved by the present invention is: in view of the shortcomings of the existing technology, a VOCs gas treatment system for coal gas purification areas and tar deep processing areas is provided, which has a simple structure, groups gases from different tanks for treatment, effectively improves treatment effects, and reduces treatment costs.

[0010] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is:

[0011] The present invention provides a VOCs gas treatment system for a coal gas purification area and a tar deep processing area. A first sealable tank group near a coke oven gas blower in the coal gas purification area includes a plurality of sealable tanks. Each sealable tank in the first sealable tank group is provided with a tank top safety device, a nitrogen pressure stabilizing device, a first VOCs gas collecting main pipe, an explosion-proof and fire-arresting breathing valve, an explosion-proof and flame-arresting device, an explosion relief valve, and a safety interlock switching device. Each sealable tank in the first sealable tank group 1 is connected to a first VOCs gas collecting main pipe via a first branch pipe. The first VOCs gas collecting main pipe is connected to a negative pressure pipeline before a primary cooler of the coke oven gas system.

[0012] A second sealable tank group in the gas purification area, away from the coke oven gas blower, includes a plurality of sealable tanks. Each sealable tank in the second sealable tank group is respectively provided with a tank top safety device, a nitrogen pressure stabilizing device, a VOCs gas collecting main pipe, an explosion-proof and fire-arresting breathing valve, an explosion-proof and flame-arresting device, an explosion relief valve, and a safety interlock switching device. Each sealable tank in the second sealable tank group is respectively connected to a second VOCs gas collecting main pipe through a second branch pipe, and the second VOCs gas collecting main pipe is connected to the negative pressure pipeline in front of the coke oven gas system blower.

[0013] The third sealable tank group in the tar deep processing area includes multiple sealable tanks. Each sealable tank in the third sealable tank group is respectively provided with a tank top safety device, a nitrogen pressure stabilizing device, a third VOCs gas collecting main pipe, an explosion-proof and fire-arresting breathing valve, an explosion-proof and flame-arresting device, an explosion relief valve, and a safety interlock switching device. Each sealable tank in the third sealable tank group is respectively connected to the third VOCs gas collecting main pipe through the third branch pipe, and the third VOCs gas collecting main pipe is connected to the negative pressure pipeline in front of the blower of the coke oven gas system.

[0014] The multiple unsealable tanks of the unsealable tank group in the gas purification area and the tar deep processing area are connected to the fourth VOCs gas collection main pipe through the fourth branch pipe, and the fourth VOCs gas collection main pipe is connected to the acid incinerator air supply.

[0015] The tank top safety device is a seal that can seal the tank pipe opening and inspection hole.

[0016] The nitrogen pressure stabilizing device includes a first-level nitrogen regulating component and a second-level nitrogen regulating component. One end of the first-level nitrogen regulating component is connected to the nitrogen source (nitrogen main pipe), and the other end of the first-level nitrogen regulating component is connected to one end of the second-level nitrogen regulating component. The other end of the second-level nitrogen regulating component is connected to the sealable tank of the corresponding sealable tank group.

[0017] A regulating valve is installed on each VOCs gas collection main pipe.

[0018] An explosion-proof and fire-retardant breathing valve is installed on each sealable tank, an explosion-proof and flame-retardant device is installed before each VOCs gas collection main pipe near the negative pressure pipe, an explosion relief valve is installed before each VOCs gas collection main pipe near the negative pressure pipe, and a buffer tank is installed before each VOCs gas collection main pipe near the negative pressure pipe.

[0019] The safety interlock switching device includes an online oxygen content detection device, a VOCs gas main quick-cut valve and an emergency release quick-cut valve. Each VOCs gas collection main is equipped with an online oxygen content detection device, a VOCs gas main quick-cut valve and an emergency release quick-cut valve near the negative pressure pipeline.

[0020] A pressure sensor and a temperature sensor are respectively installed in front of each VOCs gas collection main pipe near the negative pressure pipe.

[0021] The fourth VOCs gas collection main pipe of the unsealable tank group is equipped with an explosion-proof and fire-retardant breathing valve, an explosion-proof flame arrester, an explosion relief valve, and a buffer tank.

[0022] A pretreatment component is set between the branch pipe of each sealable tank in the sealable tank group and the VOCs gas collection main pipe; a pretreatment component is set between the fourth branch pipe of multiple non-sealable tanks in the non-sealable tank group in the coal gas purification area and the tar deep processing area and the fourth VOCs gas collection main pipe.

[0023] The technical solution of the present invention is adopted, and the working principle and beneficial effects are as follows:

[0024] The VOCs gas treatment system in the coal gas purification area and tar deep processing area of the present invention, BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The following is a brief description of the contents and symbols in the drawings of this specification:

[0026] Figure 1 This is a schematic diagram of the overall connection structure of the VOCs gas treatment system in the coal gas purification area and the tar deep processing area of the present invention;

[0027] Figure 2 This is a schematic structural diagram of the primary nitrogen regulating component of the nitrogen pressure stabilizing device of the VOCs gas treatment system in the coal gas purification area and the tar deep processing area of the present invention;

[0028] Figure 3 This is a schematic structural diagram of the secondary nitrogen regulating component of the nitrogen pressure stabilizing device of the VOCs gas treatment system in the coal gas purification area and the tar deep processing area according to the present invention;

[0029] Figure 4 This is a schematic structural diagram of the VOCs gas collection main pipe of the VOCs gas treatment system in the coal gas purification area and the tar deep processing area of the present invention;

[0030] Figure 5 This is a schematic diagram of the arrangement of explosion relief valves and flame arresters in the VOCs gas treatment system in the coal gas purification area and tar deep processing area of the present invention;

[0031] Figure 6 This is a schematic diagram of the layout structure of the buffer tanks of the VOCs gas treatment system in the coal gas purification area and the tar deep processing area of the present invention;

[0032] Figure 7 This is a schematic structural diagram of the safety interlock switching device of the VOCs gas treatment system in the coal gas purification area and the tar deep processing area according to the present invention;

[0033] The marks in the accompanying drawings are: 1. First sealable tank group; 2. First VOCs gas collecting main pipe; 3. First branch pipe; 4. Negative pressure pipeline in front of the primary cooler of the coke oven gas system; 5. Second sealable tank group; 6. Second branch pipe; 7. Second VOCs gas collecting main pipe; 8. Negative pressure pipeline in front of the blower of the coke oven gas system; 9. Third sealable tank group; 10. Third VOCs gas collecting main pipe; 11. Third branch pipe; 12. Pretreatment component; 13. Fourth branch pipe; 14. Fourth VOCs gas collecting main pipe; 15. Air supply of acid incinerator; 16. Unsealable tank group. DETAILED DESCRIPTION

[0034] The following describes the embodiments with reference to the accompanying drawings to further explain in detail the specific embodiments of the present invention, such as the shapes, structures, mutual positions and connection relationships between the various components involved, the functions and working principles of the various components.

[0035] As attached Figure 1 -Attached Figure 7As shown, the present invention is a VOCs gas treatment system for a gas purification area and a tar deep processing area. The first sealable tank group 1 in the gas purification area close to the coke oven gas blower includes a plurality of sealable tanks. Each sealable tank in the first sealable tank group 1 is respectively provided with a tank top safety device, a nitrogen pressure stabilizing device, a first VOCs gas collecting main pipe 2, an explosion-proof fire-blocking breathing valve, an explosion-proof flame arrester, an explosion relief valve, and a safety interlock switching device. Each sealable tank in the first sealable tank group 1 is connected to the first VOCs gas collecting main pipe 2 through a first branch pipe 3, and the first VOCs gas collecting main pipe 2 is connected to the negative pressure pipeline 4 before the primary cooler of the coke oven gas system; the second sealable tank group 5 in the gas purification area away from the coke oven gas blower includes a plurality of sealable tanks. Each sealable tank in the second sealable tank group 5 is respectively provided with a tank top safety device, a nitrogen pressure stabilizing device, VOCs gas collection main pipe, explosion-proof and fire-arresting breathing valve, explosion-proof flame arrester, explosion relief valve, safety interlock switching device, each sealable tank of the second sealable tank group 5 is connected to the second VOOs gas collection main pipe 7 through the second branch pipe 6, and the second VOCs gas collection main pipe 7 is connected to the negative pressure pipeline 8 before the blower of the coke oven gas system; the third sealable tank group 9 in the tar deep processing area includes multiple sealable tanks, and each sealable tank of the third sealable tank group 9 is respectively provided with a tank top safety device, a nitrogen pressure stabilizing device, a third VOCs gas collection main pipe 10, explosion-proof and fire-arresting breathing valve, explosion-proof flame arrester, explosion relief valve, and safety interlock switching device, each sealable tank of the third sealable tank group 9 is connected to the third VOCs gas collection main pipe 10 through the third branch pipe 11, and the third VOCs gas collection main pipe is connected to the negative pressure pipeline 8 before the blower of the coke oven gas system. The multiple non-sealable tanks of the non-sealable tank group 16 in the gas purification area and the tar deep processing area are connected to the fourth VOCs gas collection main 14 through the fourth branch pipe 13, and the fourth VOCs gas collection main 14 is connected to the acid incinerator air supply 15. The above structure proposes an improved technical solution to the shortcomings of the existing technology. Since there are many tanks (dozens) in the gas purification area and tar deep processing area of the coking industry's operating area, and they are distributed relatively dispersedly, if the VOCs gas from dozens of sealable tanks is collected and sent to the negative pressure gas system, it is not only difficult to stably control the pressure, but also because the gas systems of different coke ovens on site are separate, the gas system of each single coke oven cannot withstand such a large amount of gas mixing alone.In combination with the distribution of tanks in the gas purification and tar deep processing areas and the actual situation of the coke oven gas system, the VOCs gases of all dozens of tanks are divided into four systems for separate treatment, mainly as follows: the first sealable tank group 1 close to the coke oven gas blower in the gas purification area includes multiple sealable tanks, and the first VOCs gas collecting main pipe 2 is connected to the negative pressure pipeline 4 in front of the coke oven gas system pre-cooler; the second sealable tank group 5 away from the coke oven gas blower in the gas purification area includes multiple sealable tanks, and the second VOCs gas collecting main pipe 7 is connected to the negative pressure pipeline 8 in front of the coke oven gas system blower; the third sealable tank group 9 in the tar deep processing area includes multiple sealable tanks, and each sealable tank of the third sealable tank group 9 is connected to the third VOCs gas collecting main pipe 10 through the third branch pipe 11, and the third VOCs gas collecting main pipe is connected to the negative pressure pipeline 8 in front of the coke oven gas system blower. The multiple non-sealable tanks in the non-sealable tank group 16 in the gas purification area and the tar deep processing area are connected to the fourth VOCs gas collection main pipe 14 through the fourth branch pipe 13. The fourth VOCs gas collection main pipe 14 is connected to the acid incinerator air distribution 15. This facilitates the reliable collection of VOCs gas.

[0036] The tank roof safety device is a seal that seals the tank pipe openings and inspection holes. To achieve complete VOCs collection and zero emissions, each tank is sealed: loose pipe openings and inspection holes on the tank are sealed with rubber seals to ensure structural tightness.

[0037] The nitrogen pressure stabilizing device includes a primary nitrogen regulating component and a secondary nitrogen regulating component. One end of the primary nitrogen regulating component is connected to the nitrogen source (nitrogen main pipe), the other end of the primary nitrogen regulating component is connected to one end of the secondary nitrogen regulating component, and the other end of the secondary nitrogen regulating component is connected to the sealable tank of the corresponding sealable tank group. A regulating valve is provided on each VOCs gas collection main pipe. In the above structure, the function of the nitrogen pressure stabilizing device is to maintain the pressure in the tank within the required range of above 300Pa. A nitrogen pressure stabilizing device is provided on each tank. The primary pressure reduction adjusts the nitrogen pressure from 500-600kPa to 80kPa; the secondary pressure stabilization injects nitrogen into the tank to maintain the pressure above 300Pa when the tank pressure is lower than 300Pa. When the pressure in the tank is higher than 300Pa, the regulating valve is completely closed to restore the gas pressure to above 300Pa.

[0038] Each sealable tank is provided with an explosion-proof and fire-resistant breathing valve, each VOCs gas collecting main pipe is provided with an explosion-proof and fire-proof device before the negative pressure pipe, each VOCs gas collecting main pipe is provided with an explosion relief valve before the negative pressure pipe, and each VOCs gas collecting main pipe is provided with a buffer tank before the negative pressure pipe. The safety interlock switching device includes an online oxygen content detection device, a VOCs gas main pipe quick-cut valve and an emergency relief quick-cut valve, each VOCs gas collecting main pipe is provided with an oxygen content online detection device, a VOCs gas main pipe quick-cut valve and an emergency relief quick-cut valve before the negative pressure pipe. Each VOCs gas collecting main pipe is provided with a pressure sensor and a temperature sensor before the negative pressure pipe. The fourth VOCs gas collecting main pipe 14 of the non-sealable tank group is provided with an explosion-proof and fire-resistant breathing valve, an explosion-proof and fire-proof device, an explosion relief valve and a buffer tank. A pretreatment component 12 is set between the branch pipe of each sealable tank in the sealable tank group and the VOCs gas collection main pipe; a pretreatment component 12 is set between the fourth branch pipe 13 of multiple non-sealable tanks in the non-sealable tank group in the coal gas purification area and the tar deep processing area and the fourth VOCs gas collection main pipe 14.

[0039] The VOCs gas treatment system in the gas purification area and tar deep processing area described in the present invention adds a breathing valve to each tank, and the working pressure of the breathing valve is -295Pa~980Pa. Because the components of the VOCs gas in the system of the present invention have high viscosity and are easily condensed when cooled, the breathing valve should be of jacketed insulation type. In addition, in accordance with safety management requirements, the breathing valves must be equipped with fire arresters. Therefore, the breathing valves all use explosion-proof and fire-retardant breathing valves with jacketed insulation. The pressure resistance of atmospheric pressure tanks is limited. In order to ensure the safety of the tanks when the breathing valves are blocked or fail, an accident pressure relief measure - a hydraulic safety valve - is configured on the tanks with a working pressure of -392Pa~1200Pa. When the flame arrester is set, one flame arrester is used and one is reserved. Cut-off and steam purge are set at both ends of the flame arrester. The flame arrester adopts a detachable fire arrester core. Steam purge and drain valves are set on the flame arrester and the pipeline.

[0040] Considering the fire and explosion hazards of benzene-containing gas, a buffer tank is installed on the VOCs gas collection main pipe. The buffer tank can reliably act as a buffer and reduce the hazards brought by fire and explosion.

[0041] The system of the present invention is heavy. Since the tank storage medium contains a large amount of heavy components such as naphthalene, anthracene, and asphalt, in order to prevent these heavy components from condensing and clogging the pipeline, the VOCs gas in the intermediate tank area of the tar deep processing is pretreated by a pretreatment component before being incorporated into the VOCs gas collection main. The pretreatment adopts washing oil, and the heavy components in the VOCs gas in the intermediate tank area are circulated and absorbed by the Venturi scrubber. The washing oil mist entrained in the exhaust gas is removed by the demisting device at the top of the tower before it exits the pretreatment device. The oil washing tower kettle is a horizontal tank with a cooling coil installed at the bottom of the horizontal tank. The cooling medium is circulating water, and the washing oil in the pretreatment device is replaced regularly.

[0042] The safety interlock switching system of the present invention is provided with a set of oxygen content online detection device, flow meter, and pneumatic quick-cut valve. The function of the flow meter is to measure the volume flow of gas in the VOCs gas main pipe; the function of the oxygen content online detector is to measure the volume fraction of oxygen contained in the VOCs gas main pipe; the main function of the pneumatic quick-cut valve is to alarm when the oxygen content in the VOCs gas system reaches 2%, and immediately cut off the VOCs gas from entering the negative pressure gas system when it reaches 3%, open the emergency relief quick-cut valve, and eliminate the possibility of excessive oxygen from the VOCs gas being introduced into the negative pressure gas system, causing the oxygen content of the existing gas system to increase. In order to timely and accurately understand the real-time situation in the VOCs gas system and ensure the safe and reliable operation of the system. In the present invention, pressure sensors and temperature sensors are respectively provided on each VOCs gas pipe.

[0043] The main process flow and control logic of the present invention are as follows: 1) During normal operation, assuming the initial pressure in the tank is 0, since the pressure in the tank is lower than the set pressure of 300Pa of the nitrogen pressure stabilizing device, the nitrogen pressure stabilizing device is opened to replenish nitrogen; when the pressure in the tank rises to 300Pa, the nitrogen pressure stabilizing device is closed; at this time, the tank is in a sealed state, neither exhaling gas nor inhaling nitrogen. When the pressure in the tank gradually rises to 500Pa due to the increase in feed or ambient temperature, the pressure regulating valve on the VOCs gas pipeline opens, and the VOCs gas is collected from the various branches of each tank to the mobile phone main pipe and then enters the negative pressure gas system; when the pressure in the tank drops below 500Pa, the regulating valve of the VOCs gas pipeline is closed, and the tank pressure is maintained at 300-500Pa. 2) When the tank is over-pressured, if the pressure in the tank rises to 980Pa due to a blockage in the pipeline or the closure of the VOCs gas main shut-off valve, the breathing valve on the top of the tank will automatically open, and some VOCs gas will be discharged into the air; when the tank pressure drops to 980Pa, the breathing valve on the top of the tank will automatically close; if the breathing valve fails due to reasons such as naphthalene crystallization, and the pressure in the tank rises to 1200Pa, the hydraulic safety valve on the top of the tank will open, and the exhaust gas will be discharged through the hydraulic safety valve to ensure that the pressure in the tank is always below 1200Pa. 3) When the tank is under-pressured, if the pressure in the tank drops to 300Pa due to discharging or temperature drop, the nitrogen pressure stabilizing device will open and inject nitrogen into the tank to increase the pressure in the tank to 300Pa. If nitrogen cannot be injected into the tank due to a malfunction of the nitrogen pressure stabilization system, when the pressure in the tank is lower than -295Pa, the breathing valve on the top of the tank will automatically open to allow air to be exhaled into the tank; when the pressure is higher than -295Pa, the breathing valve on the top of the tank will automatically close to ensure that the pressure in the tank is always higher than -295Pa; if the breathing valve malfunctions due to reasons such as naphthalene crystallization, and the pressure in the tank drops to -392Pa, the hydraulic safety valve on the top of the tank will open and air will be sucked in through the hydraulic safety valve to ensure that the pressure in the tank is always lower than or higher than -392Pa. 4) When the oxygen content exceeds the standard, in order to ensure the safe and stable operation of the existing gas system, the oxygen content alarm signal of the VOCs gas system main pipe will be interlocked with the pneumatic quick-cut valve at the end of the VOCs gas system. When the oxygen content in the VOCs gas system reaches 2%, an alarm will be sounded. When it reaches 3%, the introduction of VOCs gas into the negative pressure gas system will be immediately shut down to eliminate the possibility of an increase in the oxygen content of the existing gas system due to the introduction of new VOCs gas into the negative pressure gas system. At the same time, the oxygen content of the VOCs gas system in the tank area can be monitored.

[0044] The present invention is described above by way of example in conjunction with the accompanying drawings. It is obvious that the specific implementation of the present invention is not limited to the above-mentioned method. As long as various improvements are made using the method concept and technical solution of the present invention, or the concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the scope of protection of the present invention.

Claims

1. A VOCs gas treatment system for coal gas purification areas and tar deep processing areas, characterized by: A first sealable tank group (1) in a gas purification area near a coke oven gas blower comprises a plurality of sealable tanks, each sealable tank of the first sealable tank group (1) is respectively provided with a tank top safety device, a nitrogen pressure stabilizing device, a first VOCs gas collecting main pipe (2), an explosion-proof fire-arresting breathing valve, an explosion-proof flame arrester, an explosion relief valve, and a safety interlock switching device, each sealable tank of the first sealable tank group (1) is respectively connected to the first VOCs gas collecting main pipe (2) via a first branch pipe (3), and the first VOCs gas collecting main pipe (2) is connected to a negative pressure pipeline (4) before a primary cooler of a coke oven gas system; A second sealable tank group (5) in a gas purification area away from the coke oven gas blower includes a plurality of sealable tanks, each sealable tank of the second sealable tank group (5) is respectively provided with a tank top safety device, a nitrogen pressure stabilizing device, a VOCs gas collecting main pipe, an explosion-proof fire-blocking breathing valve, an explosion-proof flame arrester, an explosion relief valve, and a safety interlock switching device, each sealable tank of the second sealable tank group (5) is respectively connected to a second VOCs gas collecting main pipe (7) through a second branch pipe (6), and the second VOCs gas collecting main pipe (7) is connected to a negative pressure pipeline (8) before the coke oven gas system blower; The third sealable tank group (9) in the tar deep processing area includes a plurality of sealable tanks. Each sealable tank in the third sealable tank group (9) is respectively provided with a tank top safety device, a nitrogen pressure stabilizing device, a third VOCs gas collecting main pipe (10), an explosion-proof fire-arresting breathing valve, an explosion-proof flame arrester, an explosion relief valve, and a safety interlock switching device. Each sealable tank in the third sealable tank group (9) is respectively connected to the third VOCs gas collecting main pipe (10) through a third branch pipe (11), and the third VOCs gas collecting main pipe is connected to the negative pressure pipeline (8) before the blower of the coke oven gas system.

2. The VOCs gas treatment system for the coal gas purification area and tar deep processing area according to claim 1 is characterized by: The multiple non-sealable tanks of the non-sealable tank group (16) in the coal gas purification area and the tar deep processing area are connected to the fourth VOCs gas collection main pipe (14) through the fourth branch pipe (13), and the fourth VOCs gas collection main pipe (14) is connected to the acid incinerator air supply (15).

3. The VOCs gas treatment system for the coal gas purification area and tar deep processing area according to claim 1 or 2, characterized in that: The tank top safety device is a seal that can seal the tank pipe opening and inspection hole.

4. The VOCs gas treatment system for the coal gas purification area and tar deep processing area according to claim 1 or 2, characterized in that: The nitrogen pressure stabilizing device includes a first-level nitrogen regulating component and a second-level nitrogen regulating component. One end of the first-level nitrogen regulating component is connected to the nitrogen source, and the other end of the first-level nitrogen regulating component is connected to one end of the second-level nitrogen regulating component. The other end of the second-level nitrogen regulating component is connected to the sealable tank of the corresponding sealable tank group.

5. The VOCs gas treatment system for the coal gas purification area and tar deep processing area according to claim 1 or 2, characterized in that: A regulating valve is installed on each VOCs gas collection main pipe.

6. The VOCs gas treatment system for the coal gas purification area and tar deep processing area according to claim 1 is characterized by: An explosion-proof and fire-retardant breathing valve is installed on each sealable tank, an explosion-proof and flame-retardant device is installed before each VOCs gas collection main pipe near the negative pressure pipe, an explosion relief valve is installed before each VOCs gas collection main pipe near the negative pressure pipe, and a buffer tank is installed before each VOCs gas collection main pipe near the negative pressure pipe.

7. The VOCs gas treatment system for the coal gas purification area and tar deep processing area according to claim 6 is characterized by: The safety interlock switching device includes an online oxygen content detection device, a VOCs gas main quick-cut valve and an emergency release quick-cut valve. Each VOCs gas collection main is equipped with an online oxygen content detection device, a VOCs gas main quick-cut valve and an emergency release quick-cut valve near the negative pressure pipeline.

8. The VOCs gas treatment system for the coal gas purification area and tar deep processing area according to claim 6 is characterized by: A pressure sensor and a temperature sensor are respectively installed in front of each VOCs gas collection main pipe near the negative pressure pipe.

9. The VOCs gas treatment system for the coal gas purification area and tar deep processing area according to claim 2 is characterized by: The fourth VOCs gas collecting main pipe (14) of the non-sealable tank group is provided with an explosion-proof and fire-retardant breathing valve, an explosion-proof and fire-retardant device, an explosion relief valve, and a buffer tank.

10. The VOCs gas treatment system for the coal gas purification area and tar deep processing area according to claim 2 is characterized by: A pretreatment component (12) is provided between a branch pipe of each sealable tank in the sealable tank group and a VOCs gas collecting main pipe; and a pretreatment component (12) is provided between a fourth branch pipe (13) of a plurality of non-sealable tanks in the non-sealable tank group (16) in the coal gas purification area and the tar deep processing area and a fourth VOCs gas collecting main pipe (14).

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