Waste gas treatment system and method

Abstract

The invention provides a waste gas treatment system and method. The waste gas treatment system comprises a first waste gas conveying pipeline, a second waste gas conveying pipeline, a cold diesel oil absorption tower and a VCU incinerator, the first waste gas conveying pipeline is connected with the cold diesel oil absorption tower, and the cold diesel oil absorption tower is connected with the VCU incinerator through the second waste gas conveying pipeline. Most oil gas with high additional economic value is recovered through the cold diesel oil absorption tower, and meanwhile, the characteristics of high concentration and high volatility of waste gas of an oil product tank area and a discharging stack platform are adapted through the characteristics of quick starting and high treatment efficiency of the VCU incinerator. Therefore, the purposes of economy, stability, safety and up-to-standard emission of the high-concentration and high-volatility waste gas treatment system for the oil product tank area and the unloading stack platform are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of waste gas treatment, and in particular to a waste gas treatment system and method. Background Art

[0002] Liquid oil products from petrochemical and coal chemical enterprises will generate high concentrations of VOCs (volatile organic compounds) in the process of tank feeding and storage, and in the process of loading and unloading vehicles at the unloading platform. So far, the conventional treatment processes for waste gas from oil tank areas and unloading platforms are condensation + activated carbon adsorption, absorption + activated carbon adsorption, TO / RTO (direct-fired waste gas incineration / regenerative incinerator) thermal oxidation and other treatment processes. With the improvement of environmental emission standards, more and more petrochemical companies require that the concentration of non-methane total hydrocarbons in VOCs waste gas be 20mg / Nm 3 Emission standards implementation.

[0003] The exhaust gas from oil tank areas and unloading platforms in conventional petrochemical enterprises has the following characteristics:

[0004] 1) The composition is complex and the exhaust gas concentration is high. The concentration of non-methane total hydrocarbons in the exhaust gas ranges from a few grams to several hundred grams. Conventional condensation, adsorption, thermal oxidation, activated carbon adsorption and other processes are difficult to achieve 20mg / Nm 3 Even if the emission standards are met, the emission concentration at the outlet of the waste gas treatment system is very likely to exceed the standards and there is a risk of explosion.

[0005] 2) Exhaust gas emissions are discontinuous, with fluctuating volumes and concentrations. The exhaust gas concentration in the tank area fluctuates with respiration and is also affected by unloading. During unloading, the exhaust gas concentration is often higher than normal, and the unloading exhaust gas is emitted in intermittent bursts. Conventional exhaust gas treatment equipment is poorly adapted to these highly volatile conditions.

[0006] 3) The waste gas concentration is high, the economic added value is high, and it has certain recovery value. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide an exhaust gas treatment system and method in view of the deficiencies in the prior art.

[0008] The technical solution of the present invention to solve the above technical problems is as follows: a waste gas treatment system, comprising: a first waste gas delivery pipeline, a second waste gas delivery pipeline, a cold diesel absorption tower and a VCU incinerator, the first waste gas delivery pipeline is connected to the cold diesel absorption tower, and the cold diesel absorption tower is connected to the VCU incinerator through the second waste gas delivery pipeline.

[0009] The beneficial effects of the technical solution of the present invention are as follows: the first exhaust gas transmission pipeline is used to transport the exhaust gas collected from the oil tank area and the unloading platform to the cold diesel absorption tower and the VCU incinerator. The cold diesel absorption tower is used to recover most of the high-concentration oil and gas. The second exhaust gas transmission pipeline is used to transport the exhaust gas absorbed by the cold diesel absorption tower to the VCU incinerator for thermal oxidation treatment. The VCU incinerator is used to further remove the oil and gas at the outlet of the cold diesel absorption tower. Most of the oil and gas with high added economic value are recovered by the cold diesel absorption tower, and at the same time, the VCU incinerator has the characteristics of fast startup and high processing efficiency to adapt to the high-concentration and high-volatility exhaust gas characteristics of the oil tank area and the unloading platform. Thereby achieving the purpose of economic, stable, safe and standard emission of the high-concentration and high-volatility exhaust gas treatment system of the oil tank area and the unloading platform.

[0010] Furthermore, the cold diesel absorption tower includes: a tower body, a demister, a packing layer, a spray layer, a heat exchanger and a circulating pump, the demister is located at the top of the tower body, the packing layer is located in the middle of the tower body, and the spray layer is located between the demister and the packing layer; an oil pool is provided at the bottom of the tower body, the oil pool is connected to the circulating pump through a pipeline, the circulating pump is connected to the heat exchanger through a pipeline, and the heat exchanger is connected to the spray layer through a pipeline.

[0011] The beneficial effects of adopting this further technical solution include: absorbents within the tower body initially recover oil vapor transported from the oil tank area and unloading platform, reducing oil vapor loss during thermal oxidation in the VCU incinerator. A mist eliminator effectively removes diesel droplets entrained in the oil vapor, ensuring that downstream pipelines and equipment are free of scaling and clogging. Oil vapor fully contacts and absorbs the diesel in the packing layer, thereby reducing oil vapor concentration. A stainless steel plate heat exchanger is installed in the pipeline between the outlet of the circulating pump and the spray layer. Chilled water is used as a cooling source, cooling the diesel on the other side of the heat exchanger to approximately 10°C. The chilled water circulation reduces the temperature of the exhaust gas and diesel within the tower to below 10°C. The cooled diesel is sprayed through the spray layer onto the packing layer, completing the absorption of oil vapor from the exhaust gas. Lowering the diesel temperature increases the solubility of light components in the oil vapor, thereby improving the diesel's efficiency in absorbing oil vapor from the exhaust gas. The circulating pump transports the diesel fuel from the cold diesel absorption tower to the spray layer after cooling it through a heat exchanger. The cold diesel fuel injected into the tower's packing layer fully interacts with the exhaust gas, absorbing the oil and gas components in the exhaust gas. Gravity forces the diesel fuel into the oil pool within the cold diesel absorption tower. The circulating pump then pumps the diesel fuel back to the spray layer, completing the cycle.

[0012] Furthermore, the demister is a stainless steel wire mesh demister, the packing layer uses stainless steel θ-ring packing, the heat exchanger is a stainless steel plate heat exchanger, the heat exchanger is connected to a chilled water supply pipeline and a chilled water return pipeline, and the cold source of the heat exchanger is chilled water; the connection position of the first exhaust gas delivery pipeline and the tower body and the connection position of the circulating pump and the tower body through the pipeline are both located below the packing layer, and the connection position of the second exhaust gas delivery pipeline and the cold diesel absorption tower is located above the demister; the circulating pump is a variable frequency centrifugal pump.

[0013] The beneficial effects of adopting this further technical solution are as follows: The demister is made of stainless steel, effectively removing diesel droplets entrained with oil and gas, ensuring that downstream pipelines and equipment are free of scaling and clogging. Oil and gas are fully contacted and absorbed by the diesel in the packing layer, thereby reducing the oil and gas concentration. The heat exchanger is a stainless steel plate heat exchanger, installed in the pipeline between the outlet of the circulating pump and the spray layer. The cooling source is chilled water, which cools the diesel on the other side of the heat exchanger to approximately 10°C. The chilled water circulation lowers the exhaust gas and diesel temperature within the tower to below 10°C. The cooled diesel is sprayed onto the packing layer through the spray layer, thereby absorbing the oil and gas in the exhaust gas. Lowering the diesel temperature increases the solubility of light components in the oil and gas, thereby improving the diesel's efficiency in absorbing the oil and gas in the exhaust gas. The circulating pump uses variable frequency control to control the cold diesel absorption tower's absorption efficiency for the oil tank area and unloading platform.

[0014] Furthermore, a VCU anti-backfire burner is installed in the VCU incinerator, and the VCU incinerator is connected to a combustion-supporting fan and a gas pipeline through pipelines.

[0015] The beneficial effects of this advanced technical solution are as follows: the VCU incinerator converts VOCs waste gas into CO2 and water vapor through high-temperature oxidation. Its core principle is to introduce oxygen-depleted, high-concentration waste gas directly into the VCU anti-flashback burner as fuel. After mixing with combustion-supporting air, it is completely burned at 800-1000°C. The VCU anti-flashback burner has a dual flame arresting function, featuring high processing efficiency, fast startup time, and no preheating required. The combustion-supporting fan is used to provide the oxygen required for the combustion of oil, gas, and natural gas.

[0016] Furthermore, the bottom of the cold diesel absorption tower is connected to a mixed solvent discharge pipeline and an absorbent feed pipeline.

[0017] The beneficial effects of adopting this further technical solution include: a mixed solvent discharge line is used for liquid level control, and diesel fuel that has absorbed oil and gas is conveyed through a pressurizing device to a designated recovery area, thereby reducing the oil and gas concentration. The absorbent is straight-run diesel fuel. A dedicated absorbent feed line is provided, equipped with a flow control valve.

[0018] Furthermore, the number of the first exhaust gas delivery pipelines is one or more, and an oxygen concentration analyzer and a solenoid valve are installed on the first exhaust gas delivery pipeline. The oxygen concentration analyzer and the solenoid valve are both connected to a control system.

[0019] The beneficial effect of adopting the above further technical solution is that the setting of the oxygen concentration analyzer and the solenoid valve allows the exhaust gas to enter the back-end exhaust gas treatment system only when the oxygen concentration in the exhaust gas is lower than 2%, thereby improving safety.

[0020] Furthermore, a pipeline explosion-proof flame arrester and an induced draft fan are installed on the second exhaust gas conveying pipeline.

[0021] The beneficial effects of adopting the above further technical solution are: the pipeline explosion-proof flame arrester is used to prevent backfire. The induced draft fan is used to provide power to transport the waste gas treated at the outlet of the cold diesel absorber to the VCU incinerator for thermal oxidation treatment.

[0022] Furthermore, the second exhaust gas delivery pipeline and the cold diesel absorption tower are both made of stainless steel.

[0023] The beneficial effects of adopting the above further technical solution are: improving corrosion resistance and high temperature resistance.

[0024] In addition, the present invention also provides a waste gas treatment method. Based on the waste gas treatment system described above, the waste gas treatment method includes: S1, recovering oil and gas in the waste gas through a cold diesel absorption tower; S2, thermally oxidizing the waste gas through a VCU incinerator.

[0025] The beneficial effects of the technical solution of this invention include: recovering a large portion of the oil and gas with high added economic value through the cold diesel absorber, while simultaneously adapting to the high-concentration and high-volatility exhaust gas characteristics of oil tank farms and unloading platforms through the fast startup and high treatment efficiency of the VCU incinerator. This achieves the goal of achieving an economical, stable, safe, and standard-compliant exhaust gas treatment system for oil tank farms and unloading platforms.

[0026] Furthermore, before step S1, the process includes: obtaining the real-time oxygen concentration and the preset oxygen concentration in the exhaust gas; judging whether the real-time oxygen concentration in the exhaust gas is lower than the preset oxygen concentration; and executing step S1 when the real-time oxygen concentration in the exhaust gas is lower than the preset oxygen concentration.

[0027] The beneficial effect of adopting the above further technical solution is that the exhaust gas is allowed to enter the back-end exhaust gas treatment system only when the oxygen concentration in the exhaust gas is lower than 2%, thereby improving safety.

[0028] Advantages of additional aspects of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A schematic structural diagram of an exhaust gas treatment system provided in an embodiment of the present invention.

[0030] Figure 2 A schematic flow chart of the exhaust gas treatment method provided in an embodiment of the present invention.

[0031] Explanation of the accompanying figures: 1. First exhaust gas conveying pipeline; 2. Second exhaust gas conveying pipeline; 3. Pipeline explosion-proof flame arrester; 4. Mixed solvent discharge pipeline; 5. Cold diesel absorption tower; 6. Stainless steel wire mesh demister; 7. Packing layer; 8. Heat exchanger; 9. VCU incinerator; 10. VCU anti-backfire burner; 11. Induced draft fan; 12. Combustion-supporting fan; 13. Circulation pump; 14. Gas pipeline. DETAILED DESCRIPTION

[0032] The principles and features of the present invention are described below with reference to the accompanying drawings. The embodiments given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0033] like Figure 1 As shown, an embodiment of the present invention provides an exhaust gas treatment system, including: a first exhaust gas delivery pipeline 1, a second exhaust gas delivery pipeline 2, a cold diesel absorption tower 5 and a VCU incinerator 9, wherein the first exhaust gas delivery pipeline 1 is connected to the cold diesel absorption tower 5, and the cold diesel absorption tower 5 is connected to the VCU incinerator 9 through the second exhaust gas delivery pipeline 2.

[0034] The beneficial effects of the technical solution of the present invention are as follows: the first exhaust gas transmission pipeline is used to transport the exhaust gas collected from the oil tank area and the unloading platform to the cold diesel absorption tower and the VCU incinerator. The cold diesel absorption tower is used to recover most of the high-concentration oil and gas. The second exhaust gas transmission pipeline is used to transport the exhaust gas absorbed by the cold diesel absorption tower to the VCU incinerator for thermal oxidation treatment. The VCU incinerator is used to further remove the oil and gas at the outlet of the cold diesel absorption tower. Most of the oil and gas with high added economic value are recovered by the cold diesel absorption tower, and at the same time, the VCU incinerator has the characteristics of fast startup and high processing efficiency to adapt to the high-concentration and high-volatility exhaust gas characteristics of the oil tank area and the unloading platform. Thereby achieving the purpose of economic, stable, safe and standard emission of the high-concentration and high-volatility exhaust gas treatment system of the oil tank area and the unloading platform.

[0035] The waste gas treatment system provided by the embodiment of the present invention can be applied, but is not limited to, in the field of waste gas treatment technology in oil tank areas and unloading platforms, where the waste gas has high concentration and high volatility.

[0036] In view of the high-concentration and high-volatility exhaust gas characteristics of oil tank areas and unloading platforms, the present invention proposes an exhaust gas treatment system that can be used for oil tank areas and unloading platforms. The exhaust gas treatment system consists of two parts: a cold diesel absorption system (cold diesel absorption tower 5) and a VCU combustion system (VCU incinerator 9). The cold diesel absorption system (cold diesel absorption tower 5) is mainly based on Henry's law and the effect of low temperature on the solubility of oil and gas, and initially recovers most of the high-concentration oil and gas; then the oil and gas at the outlet of the cold diesel absorption system are further removed through the VCU combustion equipment (VCU incinerator) with high processing efficiency and extremely fast startup time.

[0037] like Figure 1 As shown, further, the cold diesel absorption tower 5 includes: a tower body, a demister, a packing layer 7, a spray layer, a heat exchanger 8 and a circulating pump 13, the demister is located at the top of the tower body, the packing layer 7 is located in the middle of the tower body, and the spray layer is located between the demister and the packing layer 7; an oil pool is provided at the bottom of the tower body, the oil pool is connected to the circulating pump 13 through a pipeline, the circulating pump 13 is connected to the heat exchanger 8 through a pipeline, and the heat exchanger 8 is connected to the spray layer through a pipeline.

[0038] The beneficial effects of adopting this further technical solution include: absorbents within the tower body initially recover oil vapor transported from the oil tank area and unloading platform, reducing oil vapor loss during thermal oxidation in the VCU incinerator. A mist eliminator effectively removes diesel droplets entrained in the oil vapor, ensuring that downstream pipelines and equipment are free of scaling and clogging. Oil vapor fully contacts and absorbs the diesel in the packing layer, thereby reducing oil vapor concentration. A stainless steel plate heat exchanger is installed in the pipeline between the outlet of the circulating pump and the spray layer. Chilled water is used as a cooling source, cooling the diesel on the other side of the heat exchanger to approximately 10°C. The chilled water circulation reduces the temperature of the exhaust gas and diesel within the tower to below 10°C. The cooled diesel is sprayed through the spray layer onto the packing layer, completing the absorption of oil vapor from the exhaust gas. Lowering the diesel temperature increases the solubility of light components in the oil vapor, thereby improving the diesel's efficiency in absorbing oil vapor from the exhaust gas. The circulating pump transports the diesel fuel from the cold diesel absorption tower to the spray layer after cooling it through a heat exchanger. The cold diesel fuel injected into the tower's packing layer fully interacts with the exhaust gas, absorbing the oil and gas components in the exhaust gas. Gravity forces the diesel fuel into the oil pool within the cold diesel absorption tower. The circulating pump then pumps the diesel fuel back to the spray layer, completing the cycle.

[0039] like Figure 1As shown, further, the demister is a stainless steel wire mesh demister 6, the packing layer 7 adopts stainless steel θ ring packing, the heat exchanger 8 is a stainless steel plate heat exchanger, the heat exchanger 8 is connected to a chilled water supply pipeline and a chilled water return pipeline, and the cold source of the heat exchanger 8 is chilled water; the connection position of the first exhaust gas delivery pipeline 1 and the tower body and the connection position of the circulating pump 13 and the tower body through the pipeline are both located below the packing layer 7, and the connection position of the second exhaust gas delivery pipeline 2 and the cold diesel absorption tower 5 is located above the demister; the circulating pump 13 is a variable frequency centrifugal pump.

[0040] The beneficial effects of adopting this further technical solution are as follows: The demister is made of stainless steel, effectively removing diesel droplets entrained with oil and gas, ensuring that downstream pipelines and equipment are free of scaling and clogging. Oil and gas are fully contacted and absorbed by the diesel in the packing layer, thereby reducing the oil and gas concentration. The heat exchanger is a stainless steel plate heat exchanger, installed in the pipeline between the outlet of the circulating pump and the spray layer. The cooling source is chilled water, which cools the diesel on the other side of the heat exchanger to approximately 10°C. The chilled water circulation lowers the exhaust gas and diesel temperature within the tower to below 10°C. The cooled diesel is sprayed onto the packing layer through the spray layer, thereby absorbing the oil and gas in the exhaust gas. Lowering the diesel temperature increases the solubility of light components in the oil and gas, thereby improving the diesel's efficiency in absorbing the oil and gas in the exhaust gas. The circulating pump uses variable frequency control to control the cold diesel absorption tower's absorption efficiency for the oil tank area and unloading platform.

[0041] like Figure 1 As shown, further, a VCU anti-backfire burner 10 is installed in the VCU incinerator 9, and the VCU incinerator 9 is connected to a combustion-supporting fan 12 and a gas pipeline 14 through pipelines.

[0042] The beneficial effects of this advanced technical solution are as follows: the VCU incinerator converts VOCs waste gas into CO2 and water vapor through high-temperature oxidation. Its core principle is to introduce oxygen-depleted, high-concentration waste gas directly into the VCU anti-flashback burner as fuel. After mixing with combustion-supporting air, it is completely burned at 800-1000°C. The VCU anti-flashback burner has a dual flame arresting function, featuring high processing efficiency, fast startup time, and no preheating required. The combustion-supporting fan is used to provide the oxygen required for the combustion of oil, gas, and natural gas.

[0043] like Figure 1 As shown, further, the bottom of the cold diesel absorption tower 5 is connected to a mixed solvent discharge pipeline 4 and an absorbent feed pipeline.

[0044] The beneficial effects of adopting this further technical solution include: a mixed solvent discharge line is used for liquid level control, and diesel fuel that has absorbed oil and gas is conveyed through a pressurizing device to a designated recovery area, thereby reducing the oil and gas concentration. The absorbent is straight-run diesel fuel. A dedicated absorbent feed line is provided, equipped with a flow control valve.

[0045] Furthermore, the number of the first exhaust gas delivery pipelines 1 is one or more, and an oxygen concentration analyzer and a solenoid valve are installed on the first exhaust gas delivery pipeline 1. The oxygen concentration analyzer 1 and the solenoid valve are both connected to a control system.

[0046] The beneficial effect of adopting the above further technical solution is that the setting of the oxygen concentration analyzer and the solenoid valve allows the exhaust gas to enter the back-end exhaust gas treatment system only when the oxygen concentration in the exhaust gas is lower than 2%, thereby improving safety.

[0047] Conventional petrochemical projects utilize nitrogen blanketing on oil tank farms. Loading and unloading trucks often contain a small amount of air in their cranes, creating a risk of mixing these two types of waste gases before they are transported to the waste gas treatment equipment. Therefore, an oxygen concentration analyzer is required on the first waste gas pipeline. Only when the oxygen concentration in the waste gas is below 2% is the waste gas allowed to enter the back-end waste gas treatment system.

[0048] like Figure 1 As shown, further, a pipeline explosion-proof flame arrester 3 and an induced draft fan 11 are installed on the second exhaust gas conveying pipeline 2.

[0049] The beneficial effects of adopting the above further technical solution are: the pipeline explosion-proof flame arrester is used to prevent backfire. The induced draft fan is used to provide power to transport the waste gas treated at the outlet of the cold diesel absorber to the VCU incinerator for thermal oxidation treatment.

[0050] like Figure 1 As shown, further, the second exhaust gas delivery pipeline 2 and the cold diesel absorption tower 5 are both made of stainless steel.

[0051] The beneficial effects of adopting the above further technical solution are: improving corrosion resistance and high temperature resistance.

[0052] like Figure 1As shown, an embodiment of the present invention provides an exhaust gas treatment system suitable for high-concentration and high-volatility exhaust gas treatment in oil tank areas and unloading platforms, comprising: a first exhaust gas transmission pipeline 1, a second exhaust gas transmission pipeline 2, a pipeline explosion-proof flame arrester 3, a mixed solvent discharge pipeline 4, a cold diesel absorption tower 5, a stainless steel wire mesh demister 6, a packing layer 7, a heat exchanger 8, a VCU incinerator 9, a VCU anti-flashback burner 10, an induced draft fan 11, a combustion-supporting fan 12, a circulation pump 13, and a control system. The cold diesel absorption tower 5, the VCU anti-flashback burner 10, the induced draft fan 11, the combustion-supporting fan 12, and the circulation pump 13 can all be connected to the control system.

[0053] The first exhaust gas delivery pipeline 1 delivers the exhaust gas collected from the oil tank area and the unloading platform to the cold diesel absorption system (cold diesel absorption tower 5) and the VCU incineration system (VCU incinerator 9). The pipeline (first exhaust gas delivery pipeline 1) delivered to the front of the cold diesel absorption tower can be one or more. An oxygen concentration analyzer needs to be installed on the pipeline (first exhaust gas delivery pipeline 1), and it is only allowed to enter the back-end exhaust gas treatment system when the oxygen concentration in the exhaust gas is lower than 2%. Among them, a solenoid valve can be provided on the first exhaust gas delivery pipeline, and the solenoid valve and the oxygen concentration analyzer can both be connected to the control system. When the oxygen concentration in the exhaust gas is lower than 2%, the solenoid valve opens. Improve safety.

[0054] The second exhaust gas delivery pipeline 2 delivers the exhaust gas after cold diesel absorption to the VCU incineration system (VCU incinerator 9) for thermal oxidation treatment. The material of the pipeline (second exhaust gas delivery pipeline 2) is stainless steel. The second exhaust gas delivery pipeline 2 connects the cold diesel absorption tower 5 and the induced draft fan 11. A pipeline explosion-proof flame arrester 3 needs to be installed on the pipeline (second exhaust gas delivery pipeline 2) to prevent backfire. There is only one pipeline between the cold diesel absorption tower and the VCU incineration system (oil and gas incineration system), and it is equipped with a flame arrester (pipeline explosion-proof flame arrester 3). The induced draft fan 11 provides power to deliver the treated exhaust gas from the outlet of the cold diesel absorption tower to the VCU incineration system (VCU incinerator 9) for thermal oxidation treatment.

[0055] The pipeline explosion-proof flame arrester 3 is a safety device that prevents flames from spreading between equipment and pipelines. It primarily consists of a housing and a filter element. The housing must be strong enough to withstand the impact pressure of an explosion.

[0056] The mixed solvent discharge line 4 is used for liquid level control, and the diesel fuel after absorbing the oil and gas is conveyed to a designated recovery area through a pressurizing device, thereby reducing the oil and gas concentration. A valve may be installed on the mixed solvent discharge line 4.

[0057] The cold diesel absorption tower 5 is constructed of stainless steel. Both the tower body and its internals are made of stainless steel. It consists of the tower body, packing layer 7, spray layer, and stainless steel wire mesh demister 6. Its primary function is to initially recover oil vapors transported from the oil tank farm and unloading platform using an absorbent (straight-run diesel) within the tower, thereby reducing oil vapor losses during thermal oxidation in the VCU incineration system (VCU incinerator 9).

[0058] The absorbent is straight-run diesel. There is a dedicated feed line (absorbent feed line) equipped with a flow control valve. There is also a dedicated diesel discharge line (mixed solvent discharge line) where the diesel after absorbing oil and gas is collected and processed uniformly.

[0059] Below the packing layer 7, an exhaust gas intake manifold is installed (which can connect to multiple exhaust gas branches, i.e., multiple first exhaust gas delivery pipelines 1). An exhaust gas outlet is located at the top of the tower, above the demister (stainless steel wire mesh demister 6). A pump inlet pipe interface is also located at the bottom of the tower. A spray layer is installed between the packing layer 7 and the demister.

[0060] The demister adopts a stainless steel wire mesh demister (stainless steel wire mesh demister 6). The stainless steel wire mesh demister 6 is made of stainless steel and can effectively remove diesel droplets entrained in oil and gas, ensuring that the back-end pipelines and equipment are not scaled or blocked.

[0061] The packing layer 7 uses stainless steel θ ring packing (theta ring packing, Dixon packing), with a specific surface area of 350m 2 / m 3 The oil and gas are fully contacted and absorbed by the diesel in the packing layer 7, thereby reducing the oil and gas concentration.

[0062] Heat exchanger 8 is a stainless steel plate heat exchanger installed in the pipeline between the outlet of the circulating pump 13 and the spray layer. The cooling source is chilled water, which cools the diesel fuel passing through heat exchanger 8 to approximately 10°C. The chilled water circulation lowers the exhaust gas and diesel fuel temperatures within the tower to below 10°C. The cooled diesel fuel is then sprayed through the spray layer onto the packing layer 7, absorbing the oil and vapor in the exhaust gas. Lowering the diesel fuel temperature increases the solubility of light components in the oil and vapor, thereby improving the diesel fuel's efficiency in absorbing the oil and vapor in the exhaust gas.

[0063] The VCU incinerator 9 consists of a furnace, a VCU flashback burner 10, a pilot light, a bottom damper, a hood, a lightning protection system, a galvanized tower, a sampling port, a monitoring platform, and a control system. The VCU incinerator 9 converts VOCs into CO2 and water vapor through high-temperature oxidation. Its core process involves introducing oxygen-depleted, high-concentration exhaust gas directly into the VCU flashback burner 10 as fuel, where it mixes with combustion air and burns completely at 800-1000°C.

[0064] The bottom of the furnace of the VCU incinerator 9 is provided with an electric adjustable damper, which can adjust the air supply volume according to the furnace temperature.

[0065] The VCU incinerator 9 is not provided with a heat recovery device.

[0066] The VCU anti-flashback burner 10 has a dual flame arresting function and is characterized by high processing efficiency, fast start-up time and no need for preheating. The VCU combustion head consists of multiple groups of burners and can be operated in stages.

[0067] The induced draft fan 11 is a variable frequency centrifugal fan with a stainless steel housing and impeller and an explosion-proof motor. Its function is to systematically pump VOCs waste gas to the VCU incinerator 9 for incineration and thermal oxidation. The post-reaction gas is discharged directly into the atmosphere.

[0068] The combustion-supporting fan 12 is a variable frequency centrifugal fan, the fan housing and impeller are made of stainless steel, and the motor is an explosion-proof motor; its function is to provide the oxygen required in the combustion process of oil, gas and natural gas.

[0069] The circulating pump 13 is a variable frequency centrifugal pump (can be a horizontal variable frequency centrifugal pump) made of stainless steel. The pump casing and impeller are made of stainless steel, and the motor is an explosion-proof motor. The diesel in the cold diesel absorption tower 5 is heat exchanged and cooled through the heat exchanger 8 and transported to the spray layer. The cold diesel injected into the packing layer 7 in the tower is in full contact with the exhaust gas, absorbing the oil and gas components in the exhaust gas, and falls into the oil pool in the cold diesel absorption tower 5 due to gravity. It is then continuously pumped to the spray layer by the circulating pump 13 to complete the cycle. The circulating pump 13 can control the absorption efficiency of the cold diesel absorption tower 5 for the oil tank area and the unloading platform through variable frequency regulation.

[0070] like Figure 2 As shown, in addition, the present invention also provides a waste gas treatment method. Based on the above-mentioned waste gas treatment system, the waste gas treatment method includes: S1, recovering oil and gas in the waste gas through a cold diesel absorption tower; S2, thermally oxidizing the waste gas through a VCU incinerator.

[0071] The beneficial effects of the technical solution of this invention include: recovering a large portion of the oil and gas with high added economic value through the cold diesel absorber, while simultaneously adapting to the high-concentration and high-volatility exhaust gas characteristics of oil tank farms and unloading platforms through the fast startup and high treatment efficiency of the VCU incinerator. This achieves the goal of achieving an economical, stable, safe, and standard-compliant exhaust gas treatment system for oil tank farms and unloading platforms.

[0072] Furthermore, before step S1, the process includes: obtaining the real-time oxygen concentration and the preset oxygen concentration in the exhaust gas; judging whether the real-time oxygen concentration in the exhaust gas is lower than the preset oxygen concentration; and executing step S1 when the real-time oxygen concentration in the exhaust gas is lower than the preset oxygen concentration.

[0073] The beneficial effect of adopting the above further technical solution is that the exhaust gas is allowed to enter the back-end exhaust gas treatment system only when the oxygen concentration in the exhaust gas is lower than 2%, thereby improving safety.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An exhaust gas treatment system, characterized in that: include: A first exhaust gas delivery pipeline, a second exhaust gas delivery pipeline, a cold diesel absorption tower and a VCU incinerator, wherein the first exhaust gas delivery pipeline is connected to the cold diesel absorption tower, and the cold diesel absorption tower is connected to the VCU incinerator through the second exhaust gas delivery pipeline.

2. The exhaust gas treatment system according to claim 1, characterized in that: The cold diesel absorption tower includes: a tower body, a demister, a packing layer, a spray layer, a heat exchanger and a circulating pump. The demister is located at the top of the tower body, the packing layer is located in the middle of the tower body, and the spray layer is located between the demister and the packing layer. An oil pool is provided at the bottom of the tower body, the oil pool is connected to the circulating pump through a pipeline, the circulating pump is connected to the heat exchanger through a pipeline, and the heat exchanger is connected to the spray layer through a pipeline.

3. The exhaust gas treatment system according to claim 2, characterized in that: The demister is a stainless steel wire mesh demister, the packing layer uses stainless steel θ-ring packing, the heat exchanger is a stainless steel plate heat exchanger, the heat exchanger is connected to a chilled water supply pipeline and a chilled water return pipeline, and the cold source of the heat exchanger is chilled water; the connection position of the first exhaust gas delivery pipeline and the tower body and the connection position of the circulating pump and the tower body through the pipeline are both located below the packing layer, and the connection position of the second exhaust gas delivery pipeline and the cold diesel absorption tower is located above the demister; the circulating pump is a variable frequency centrifugal pump.

4. The exhaust gas treatment system according to claim 1, characterized in that: A VCU anti-backfire burner is installed in the VCU incinerator, and the VCU incinerator is connected to a combustion-supporting fan and a gas pipeline through pipelines.

5. The exhaust gas treatment system according to claim 1, characterized in that: The bottom of the cold diesel absorption tower is connected with a mixed solvent discharge pipeline and an absorbent feed pipeline.

6. The exhaust gas treatment system according to claim 1, characterized in that: The number of the first exhaust gas delivery pipelines is one or more. An oxygen concentration analyzer and a solenoid valve are installed on the first exhaust gas delivery pipeline. The oxygen concentration analyzer and the solenoid valve are both connected to a control system.

7. The exhaust gas treatment system according to claim 1, characterized in that: The second exhaust gas delivery pipeline is equipped with a pipeline explosion-proof flame arrester and an induced draft fan.

8. The exhaust gas treatment system according to claim 1, characterized in that: The second exhaust gas delivery pipeline and the cold diesel absorption tower are both made of stainless steel.

9. A method for treating waste gas, characterized in that: Based on the exhaust gas treatment system according to any one of claims 1 to 8 above, the exhaust gas treatment method includes: S1. Recover the oil and gas in the exhaust gas through the cold diesel absorption tower; S2. The exhaust gas is subjected to thermal oxidation treatment through the VCU incinerator.

10. The waste gas treatment method according to claim 9, characterized in that: Before step S1, the following steps are included: Obtain real-time oxygen concentration and preset oxygen concentration in exhaust gas; Determine whether the real-time oxygen concentration in the exhaust gas is lower than the preset oxygen concentration; When the real-time oxygen concentration in the exhaust gas is lower than the preset oxygen concentration, step S1 is executed.

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