Efficient and stable recovery treatment system for tank washing waste gas

Abstract

The invention belongs to the technical field of waste gas treatment, and particularly relates to an efficient and stable recovery treatment system for tank washing waste gas, in which most of water in the tank washing waste gas is removed through a first separation mechanism, and the tank washing waste gas is cooled and primarily reduced in concentration through a condensation separation mechanism, so that the problems of high temperature and high water content of the tank washing waste gas are solved; the problem that the instantaneous concentration of VOC is high is solved, oil in the tank washing waste gas is physically absorbed through the absorption mechanism, the problem that the instantaneous concentration of VOC in the tank washing waste gas is high is further solved, VOC in the tank washing waste gas is recycled, and the tank washing waste gas, combustion-supporting gas and oxygen are mixed through the gas mixing mechanism and then conveyed to the combustion mechanism. The mixed gas is ignited, and the purified gas reaching the standard is discharged into the atmospheric environment. The problems that an existing tank washing waste gas treatment device is poor in stability, high in operation cost, large in treatment risk and difficult to achieve standard emission are solved, and safe, efficient and stable standard emission of tank washing waste gas is achieved.

Description

Technical Field

[0001] This invention belongs to the field of waste gas treatment technology, and in particular relates to a high-efficiency and stable recovery and treatment system for waste gas from washing tanks. Background Technology

[0002] Currently, most refining and chemical enterprises still use manual open-air steam cleaning technology, which originated in the 1960s, for their tank cleaning operations. This technology has significant shortcomings. On the one hand, it results in a harsh production environment, requiring operators to work in a high-temperature, high-humidity environment accompanied by exhaust gases, leading to high labor intensity. On the other hand, energy consumption remains high, with large steam consumption and low heat utilization rate. Furthermore, the tank cleaning efficiency is far from meeting the needs of modern production, and each tank cleaning session takes a long time, affecting overall production turnover efficiency.

[0003] During the washing tank process, open operation generates a large amount of waste gas. Direct emission of this waste gas not only causes significant pollution to the surrounding environment but also poses safety hazards. To improve this situation, upgrading the washing tank system to a closed-loop cleaning technology has become an inevitable trend. The closed-loop design can effectively reduce fugitive emissions of waste gas and minimize the impact on the environment and personnel.

[0004] However, the treatment of volatile organic compounds (VOCs) at domestic tank washing stations is still in its early stages, and the relevant technological systems are not yet mature. Tank washing exhaust gas itself has distinct characteristics: high outlet temperature, often far exceeding the adaptability range of conventional exhaust gas treatment devices; high water content, easily leading to corrosion and liquid accumulation within the treatment system; large fluctuations in instantaneous VOC concentrations, with peak concentrations frequently exceeding the design load of conventional treatment processes; and high oxygen content, increasing safety risks during treatment. These characteristics result in the existing tank washing exhaust gas treatment devices generally facing problems of poor stability, high operating costs, and high treatment risks, making it difficult to achieve long-term stable emission compliance and failing to meet the actual environmental protection and safety requirements of refining and chemical enterprises for tank washing operations. Summary of the Invention

[0005] The purpose of this invention is to provide a highly efficient and stable recovery and treatment system for waste gas from washing tanks, in order to solve the above-mentioned problems.

[0006] To achieve the above objectives, the present invention provides the following solution:

[0007] A high-efficiency and stable recovery and treatment system for waste gas from a washing tank includes: a condensation recovery unit, an absorption unit, and a combustion unit connected in sequence;

[0008] The condensation recovery unit includes a first separation mechanism, which is connected to a condensation separation mechanism.

[0009] The absorption unit includes an absorption mechanism, which is connected to the condensation separation mechanism.

[0010] The combustion unit includes a gas mixing mechanism, which is connected to the absorption mechanism and a combustion mechanism. An ignition mechanism is provided on the combustion mechanism.

[0011] In the efficient and stable recovery and treatment system for waste gas from the washing tank of the present invention, the first separation mechanism includes a filter separator, which is connected to the vacuum pump of the washing tank station, and is connected to an oil storage tank. The filter separator is also connected to the condensation separation mechanism.

[0012] In the efficient and stable recovery and treatment system for washing tank exhaust gas of the present invention, the condensation separation mechanism includes a washing tank exhaust gas condenser and deliquometer, which is connected to the filter separator, the washing tank exhaust gas condenser and deliquometer is connected to the oil storage tank, the washing tank exhaust gas condenser and deliquometer is connected to the absorption mechanism, and the washing tank exhaust gas condenser and deliquometer is connected to a refrigeration unit.

[0013] In the efficient and stable recovery and treatment system for washing tank exhaust gas of the present invention, the absorption mechanism includes an absorption tower. The top outlet of the absorption tower is connected to a separator, which is connected to the gas mixing mechanism. The top liquid inlet of the absorption tower is connected to an absorption lean oil pump, which is connected to an external absorption lean oil supply device. The absorption lean oil pump is connected to a lean oil cooler. The side wall air inlet of the absorption tower is connected to the washing tank exhaust gas condenser and desiccant. The side wall liquid inlet of the absorption tower is connected to an oil transfer pump, which is connected to the oil storage tank. The bottom liquid outlet of the absorption tower is connected to an absorption rich oil pump.

[0014] In the efficient and stable recovery and treatment system for waste gas from the washing tank of the present invention, the gas mixing mechanism includes a turbulent mixing chamber, the bottom of which is connected to an oxidation fan and the separator, the side wall of which is connected to an external combustion-supporting gas supply device, and the top of which is connected to the combustion mechanism.

[0015] In the efficient and stable recovery and treatment system for waste gas from the washing tank of the present invention, a gas-supporting pressure regulating valve and a gas-supporting shut-off valve are provided between the turbulent mixing chamber and the external gas-supporting supply device.

[0016] In the efficient and stable recovery and treatment system for waste gas from the washing tank of the present invention, a third waste gas fan and a waste gas shut-off valve are provided between the turbulent mixing chamber and the separator.

[0017] In the efficient and stable recovery and treatment system for waste gas from the washing tank of the present invention, the combustion mechanism includes a high-temperature resistant chimney, and a metal fiber surface burner is provided at the bottom end of the high-temperature resistant chimney. The bottom end of the high-temperature resistant chimney is connected to the turbulent mixing chamber.

[0018] In the efficient and stable recovery and treatment system for waste gas from the washing tank of the present invention, the ignition mechanism includes an ignition gun, the ignition end of the ignition gun is correspondingly arranged with the metal fiber surface burner, and the air inlet end of the ignition gun is provided with an ignition gas pressure regulating valve and an ignition gas cut-off valve.

[0019] In the efficient and stable recovery and treatment system for waste gas from the washing tank of the present invention, the side wall air inlet of the absorption tower is connected to other waste gas inlet devices.

[0020] Compared with the prior art, the present invention has the following advantages and technical effects:

[0021] In this invention, within the condensation recovery unit, most of the water in the washing tank exhaust gas is removed by the first separation mechanism. The condensation separation mechanism cools and initially reduces the concentration of the washing tank exhaust gas, solving the problems of high temperature and high water content in the washing tank exhaust gas and alleviating the problem of high instantaneous VOC concentration. The absorption mechanism of the absorption unit physically absorbs the oil in the washing tank exhaust gas, further alleviating the problem of high instantaneous VOC concentration in the washing tank exhaust gas and realizing the recovery of VOC in the washing tank exhaust gas. The washing tank exhaust gas, combustion gas, and oxygen are mixed by the gas mixing mechanism and then transported to the combustion mechanism. The mixed gas is ignited by the ignition mechanism, and the purified gas is discharged into the atmosphere.

[0022] This invention solves the problems of poor stability, high operating costs, high treatment risks, and difficulty in achieving emission standards in existing waste gas treatment devices for washing tanks, and achieves safe, efficient, and stable emission of waste gas from washing tanks in compliance with emission standards. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the structure of the present invention;

[0025] The components include: 1. Tank washing exhaust gas; 2. Other exhaust gas; 3. Lean oil absorption; 4. Rich oil absorption; 5. Combustion generator; 6. Ignition gas; 7. Oxidant; 8. Standard purified gas; P1-1. Other exhaust gas conveying device; P1-2. Tank washing exhaust gas conveying device; P1-3. Lean oil absorption cooling device; 101. Filter separator; 102. Flame arrester; 103. Condenser and desliming device; 104. Oil storage tank; 105. Refrigeration unit; 106. Oil transfer pump; 201-1. Other exhaust gas fan; 201-2. Tank washing... Exhaust gas fan; 202, valve; 202-1, rich oil absorption pump; 202-2, lean oil absorption pump; 203, lean oil cooler; 204, absorption tower; 205, separator; 301, third exhaust gas fan; 302, oxidation fan; 303, exhaust gas shut-off valve; 304, combustion gas pressure regulating valve; 305, combustion gas shut-off valve; 306, ignition gas pressure regulating valve; 307, ignition gas shut-off valve; 308, ignition gun; 309, turbulent mixing chamber; 310, metal fiber surface burner; 311, high-temperature resistant chimney. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] Reference Figure 1 The present invention discloses a high-efficiency and stable recovery and treatment system for waste gas from a washing tank, comprising: a condensation recovery unit, an absorption unit, and a combustion unit connected in sequence;

[0029] The condensation recovery unit includes a first separation mechanism, which is connected to a condensation separation mechanism;

[0030] The absorption unit includes an absorption mechanism, which is connected to a condensation and separation mechanism;

[0031] The combustion unit includes a gas mixing mechanism, which is connected to an absorption mechanism and a combustion mechanism. An ignition mechanism is provided on the combustion mechanism.

[0032] This system adopts a modular design, consisting of sequentially connected condensation recovery units, absorption units, and combustion units. Each unit functions independently, while also forming an organic whole through pipelines and control logic, achieving full-process coverage of "pretreatment-deep purification-final disposal".

[0033] The core design concept is reflected in three aspects: First, "graded treatment and cascaded recovery," which removes most of the water and heavy organic components through the condensation recovery unit, further reduces the VOCs concentration through the absorption unit, and achieves complete oxidation of residual organic matter through the combustion unit, while simultaneously recovering usable oil products at each stage; Second, "adaptive adjustment and strong anti-fluctuation capability," which enables the system to adapt to instantaneous changes in exhaust gas temperature, concentration, and flow rate through multi-parameter monitoring and dynamic control; Third, "safety first and energy efficiency optimization," which integrates multiple safety protection devices and reduces operating energy consumption through cascaded energy utilization.

[0034] In one alternative embodiment, the first separation mechanism includes a filter separator 101, which is connected to the vacuum pump of the washing tank station, an oil storage tank 104, and a condensation separation mechanism.

[0035] In one alternative embodiment, the condensation separation mechanism includes a condenser 103, which is connected to a filter separator 101, an oil storage tank 104, and an absorption mechanism. The condenser 103 is also connected to a refrigeration unit 105.

[0036] As the first stage of the system, the condensation recovery unit is mainly responsible for cooling, dehydrating, removing heavy components, and performing preliminary purification of the waste gas, laying a stable gas source foundation for subsequent treatment. Its core consists of a first separation mechanism and a condensation separation mechanism, achieving pretreatment and resource recovery of the waste gas through the synergistic effect of physical separation and low-temperature condensation.

[0037] The first separation unit, with filter separator 101 as its core, is directly connected to the vacuum pump of the washing tank station to receive high-temperature exhaust gas from the washing tank station. The filter separator 101 adopts a multi-layer composite filtration structure. The upper layer is a metal wire mesh filter, which can intercept solid particles (such as metal shavings, dust, etc.) entrained in the exhaust gas. The middle layer is a corrugated plate coalescer, which uses inertial collision and surface tension to coalesce the tiny droplets (oil droplets, water droplets) in the exhaust gas into larger droplets. The lower layer is a gravity separation zone, where the coalesced droplets settle to the bottom under the action of gravity, achieving efficient separation of the gas phase from the condensed droplets and solids.

[0038] The separated oil flows into the oil storage tank 104 through the bottom pipe for temporary storage and subsequent recovery; the purified gas phase enters the condensation and separation unit. To ensure system safety, a flame arrester 102 is installed between the filter separator 101 and the washing station. It adopts a corrugated metal sheet structure, which prevents flame propagation through heat dissipation and the wall effect, effectively isolating the washing station and the condensation recovery unit, and preventing the cross-regional spread of backfire or explosion accidents.

[0039] In addition, the first separation unit integrates a comprehensive set of monitoring instruments, including an inlet air temperature sensor, a pressure transmitter, a flow meter, and a solid impurity concentration detector. These instruments collect exhaust gas parameters in real time, providing data support for system control and alerting operators to clean the filters promptly through impurity concentration warnings, thus preventing blockages that could lead to a sudden increase in system pressure.

[0040] The core equipment of the condensation separation mechanism is the condenser-dehydrator 103, which is connected to the gas phase outlet of the filter separator 101 to receive the pretreated waste gas. This equipment adopts a shell-and-tube heat exchanger structure, with the shell side serving as the waste gas passage and the tube side as the refrigerant passage, achieving cooling through indirect heat exchange between the refrigerant and the waste gas.

[0041] The cooling capacity of the condenser 103 is provided by the matching refrigeration unit 105. In actual operation, the system can dynamically adjust the cooling capacity according to the humidity and VOCs composition of the exhaust gas through the PLC control system, so that the condensation temperature fluctuates adaptively within the set range. During the condensation process, water vapor and heavy organic components in the exhaust gas reach saturation due to the temperature drop and condense into a liquid phase. This liquid flows down the inner wall of the condenser 103 and flows into the oil storage tank 104 through the bottom pipe, where it is combined with the oil recovered by the first separation mechanism for further processing. The non-condensable gas phase is discharged from the top outlet of the condenser 103 and enters the absorption unit for further processing.

[0042] The oil storage tank 104, serving as the resource recovery center of the condensate recovery unit, adopts a horizontal tank structure and is equipped with a level gauge, temperature sensor, and stirring device. The level gauge monitors the liquid level in the tank in real time. When the liquid level reaches the set upper limit, the oil transfer pump 106 is automatically activated to pump the recovered oil to the absorption tower 204 or the external sludge pipeline. If the oil purity is high (heavy component content ≥80%), it is transported to the absorption tower as a supplementary absorbent; if the purity is low, it is sent to the external treatment unit for refining and recovery. The stirring device prevents oil stratification and ensures stable transportation.

[0043] In one alternative embodiment, the absorption mechanism includes an absorption tower 204. The top outlet of the absorption tower 204 is connected to a separator 205, which is connected to a gas mixing mechanism. The top inlet of the absorption tower 204 is connected to a lean oil absorption pump 202-2, which is connected to an external lean oil absorption supply device. The lean oil absorption pump 202-2 is connected to a lean oil cooler 203. The side inlet of the absorption tower 204 is connected to a condenser / dehydrator 103. The side inlet of the absorption tower 204 is connected to an oil transfer pump 106, which is connected to an oil storage tank 104. The bottom outlet of the absorption tower 204 is connected to a rich oil absorption pump 202-1.

[0044] As the second stage of the system, the absorption unit primarily uses physical absorption principles to further reduce the concentration of VOCs in the exhaust gas, while simultaneously achieving efficient VOCs recovery. Its core component is the absorption mechanism, which transfers VOCs from the gas phase to the liquid phase through counter-current contact between the absorbent and the exhaust gas. This reduces the processing load on the subsequent combustion unit and improves resource recovery efficiency.

[0045] The absorption mechanism, centered on absorption tower 204, employs a packed tower structure, characterized by a large specific surface area, high mass transfer efficiency, and low resistance. The multi-port design of absorption tower 204 enables multi-directional gas-liquid flow and efficient contact; the specific connection relationships are as follows:

[0046] Side wall air inlet: connected to the non-condensable gas phase outlet of the condenser deslimer 103, and other exhaust gas inlet interfaces are reserved at the same time, which can be connected to vehicle loading exhaust gas, ship loading exhaust gas, tank area exhaust gas, etc., to achieve the coordinated treatment of multi-source exhaust gas.

[0047] Top inlet: Connected to the lean oil absorption pump 202-2 via a pipeline, it receives lean oil 3 (usually light alkanes or a special absorbent) from the outside.

[0048] Side wall liquid inlet: connected to oil transfer pump 106, receiving recovered oil from oil storage tank 104 as a supplementary absorbent.

[0049] Bottom outlet: Connected to the rich oil absorption pump 202-1 via a pipeline, the rich oil after VOCs absorption is transported to the external pipeline network for recovery.

[0050] Top outlet: Connected to separator 205, it discharges the absorbed non-condensable gas.

[0051] The separator 205, connected to the top outlet of the absorber tower 204, employs a cyclone separation structure. It utilizes centrifugal force to separate absorbent droplets entrained in the non-condensable gas (separation efficiency ≥95% for droplets with a particle size ≥10μm). This design reduces absorbent loss (lowering the loss rate to below 0.5%) and prevents droplets from entering subsequent combustion units, thus avoiding combustion instability (such as flame pulsation or sudden temperature rise). The separated droplets return to the absorber tower 204 through the bottom reflux pipe, achieving absorbent recycling.

[0052] In one alternative embodiment, the gas mixing mechanism includes a turbulent mixing chamber 309, the bottom of which is connected to an oxidation fan 302 and a separator 205, the side wall of which is connected to an external combustion-supporting gas supply device, and the top of which is connected to a combustion mechanism.

[0053] In one alternative embodiment, a gas-supporting pressure regulating valve 304 and a gas-supporting shut-off valve 305 are provided between the turbulent mixing chamber 309 and the external gas-supporting supply device.

[0054] In one alternative, a third exhaust gas fan 301 and an exhaust gas shut-off valve 303 are provided between the turbulent mixing chamber 309 and the separator 205.

[0055] In one alternative embodiment, the combustion mechanism includes a high-temperature resistant chimney 311, with a metal fiber surface burner 310 disposed at the bottom end of the high-temperature resistant chimney 311, and the bottom end of the high-temperature resistant chimney 311 being connected to the turbulent mixing chamber 309.

[0056] In one alternative embodiment, the ignition mechanism includes an ignition gun 308, the ignition end of which is correspondingly arranged with the metal fiber surface burner 310, and the air inlet end of the ignition gun 308 is provided with an ignition gas pressure regulating valve 306 and an ignition gas shut-off valve 307.

[0057] As the third stage of the system, the combustion unit is responsible for completely oxidizing residual VOCs into harmless substances (CO2, H2O), ensuring that the final emissions meet standards. Its core consists of a gas mixing mechanism, a combustion mechanism, and an ignition mechanism. It employs fully premixed surface combustion technology, featuring high combustion efficiency, stable temperature, and strong anti-interference capabilities.

[0058] The gas mixing mechanism is centered around the turbulent mixing chamber 309. Through the turbulent mixing of multiple airflows, it ensures that the gas components entering the combustion mechanism are uniform and the concentration is stable. The turbulent mixing chamber 309 is a cylindrical cavity (diameter 1-1.5m, length 3-4m), with multiple layers of guide plates and turbulence-inducing components inside, so that the gas forms strong turbulence during the flow process, and the mixing uniformity can reach more than 95%.

[0059] The intake system of the turbulent mixing chamber 309 includes three core airflow paths:

[0060] Non-condensable gas from the absorption unit is pressurized by the third exhaust gas fan 301 and then enters the turbulent mixing chamber 309. The fan is frequency-controlled and its speed can be dynamically adjusted according to the exhaust gas flow rate to ensure stable intake. An exhaust gas shut-off valve 303 is installed between the two to quickly cut off the exhaust gas supply in the event of an emergency system shutdown to prevent backfire.

[0061] Oxidant (air): supplied by oxidation blower 302, with an outlet pressure of 8-12 kPa and flow rate automatically adjusted according to the VOCs concentration in the exhaust gas (air-fuel ratio controlled at 1.2-1.5 to ensure complete combustion).

[0062] Combustion gas (usually natural gas): Sourced from an external combustion gas supply device, the combustion gas pressure is reduced to 3-5 kPa by the combustion gas pressure regulating valve 304 before entering the turbulent mixing chamber 309. The function of the combustion gas is to reduce the VOCs concentration in the exhaust gas to below 500 mg / m³. 3It replenishes heat to maintain a stable combustion temperature. The auxiliary combustion gas pressure regulating valve 304 and the auxiliary combustion gas shut-off valve 305 (pneumatic shut-off valve) are connected in series. The former ensures stable pressure, while the latter quickly cuts off the supply in case of abnormal combustion.

[0063] The mixing ratio of the three gases in the turbulent mixing chamber 309 is dynamically controlled by the PLC system based on real-time monitoring of VOCs concentration, flow rate, and oxygen content, ensuring that the calorific value of the mixed gas remains stable at 800–1500 kcal / m³. 3 This provides a foundation for stable combustion.

[0064] The combustion mechanism consists of a metal fiber surface burner 310 and a high-temperature resistant chimney 311, employing fully premixed surface combustion technology (High-Efficiency Combustion System HCS), which has the following technical advantages: First, it is not limited by oxygen content and does not require strict control of the excess air coefficient; second, it has low sensitivity to the concentration of VOCs in the incoming air, within the range of 500–5000 mg / m³. 3 It can burn stably within a wide concentration range; thirdly, it has high combustion efficiency (≥99%), with VOCs removal rate reaching over 99.5%. The high-temperature resistant chimney 311 has a double-layer structure: the inner layer uses refractory castable (temperature resistance ≥1200℃), and the outer layer is an insulation layer (thermal conductivity ≤0.1W / (m·K)), ensuring safe transport of high-temperature flue gas while reducing heat loss. The chimney height is designed according to environmental protection requirements (usually ≥15m) to ensure that the dispersion of purified gas emissions meets atmospheric environmental quality standards.

[0065] In one alternative, the side wall inlet of the absorption tower 204 is connected to other waste gas inlet devices.

[0066] Specific work process:

[0067] High-temperature, high-moisture-content, and high-concentration waste gas 1 from the washing tank station, with a temperature of approximately 200℃ and a pressure of 0-20 kPa, is pumped by the vacuum pump of the washing tank station to the condensation recovery unit. The filter separator 101 separates the gas phase from condensate droplets and solids. The oil enters the oil storage tank 104. A flame arrester 102 ensures safe isolation between the washing tank station and the condensation recovery unit. Various instruments monitor the inlet air parameters. After pretreatment by the filter separator 101, the waste gas enters the condenser dehydrator 103 for condensation and dehydration. The cooling capacity of the device 103 is provided by the refrigeration unit 105. After condensation, the temperature of the waste gas from the washing tank is controlled at 5-10℃ (or a larger range), which removes most of the water and heavy organic components in the gas phase. The removed liquid phase enters the oil storage tank 104 to achieve oil recovery. The oil transfer pump 106, controlled by the level gauge installed on the oil storage tank 104, delivers the oil to the absorption tower 204 or other external waste oil pipelines to achieve oil recovery and preliminary concentration reduction. The non-condensable gas phase enters the absorption tower 204, and the system automatically determines the operation based on the non-condensable gas outlet temperature.

[0068] The non-condensable gas from the condenser 103 is used to determine whether a tank washing exhaust gas conveying device P1-2 is needed, depending on the actual situation. The tank washing exhaust gas conveying device P1-2 includes a tank washing exhaust gas fan 201-2. Depending on the specific project situation, other exhaust gas conveying devices P1-1 can be added. Other exhaust gas conveying devices P1-1 include other exhaust gas fans 201-1 and valves 202. Other exhaust gases 2, such as loading exhaust gas, loading ship exhaust gas, and tank area exhaust gas, enter the system of this invention from the absorption unit to achieve stable fluctuations in oil and gas concentration and reduce the instantaneous increase or decrease of VOC concentration. The lean oil from the external absorption unit 3 can be cooled using either the refrigeration unit 105 of the condensation recovery unit or the lean oil absorption cooling device P1-3 to enhance the absorption effect. The lean oil absorption cooling device P1-3 includes a lean oil cooler 203. The lean oil is transported to the top of the absorption tower 204 via the lean oil absorption pump 202-2, where it is sprayed from the top of the absorption tower 204 and comes into countercurrent contact with the waste gas, physically absorbing the VOC components in the waste gas. Non-condensable gases flow out from the top of the tower. The rich oil from the absorption unit 4 is transported to the external pipeline network using the rich oil absorption pump 202-1 to achieve oil recovery. The non-condensable gases at the top of the tower pass through the separator 205 to separate the droplets carried out by the washing tank waste gas from the absorption tower 204, reducing the risks of subsequent transportation and treatment.

[0069] Non-condensable gas from the absorption unit is pressurized and transported to the turbulent mixing chamber 309 by the third exhaust gas fan 301. Oxidant 7 is pressurized and transported to the turbulent mixing chamber 309 by the oxidation fan 302. Combustion gas 5 is reduced to a certain pressure range by the combustion gas pressure regulating valve 304 before entering the turbulent mixing chamber 309. The three gases are turbulently mixed in the turbulent mixing chamber 309 and then enter the metal fiber surface burner 310 for fully premixed surface combustion. After passing through the high-temperature chimney 311, the purified gas 8 is discharged in compliance with emission standards. Ignition gas 6 is depressurized, and the ignition gas cut-off valve 307 is opened. Ignition is completed using the ignition gun 308 and oxidant 7. This system is also equipped with multiple detection instruments to measure the gas pressure, temperature, flow rate, concentration, liquid level, etc. at each stage. The settings of each detection instrument are conventional in this field, and those skilled in the art can select according to actual needs.

[0070] This system utilizes combustion temperature monitoring to achieve automatic system adjustment. It employs a fully premixed surface combustion technology—a high-efficiency combustion system (HCS) with a porous media burner head—that does not restrict oxygen content, exhibits low sensitivity to incoming VOC concentration, and boasts excellent performance indicators, thus achieving safe, efficient, and stable emissions compliance.

[0071] In this invention, within the condensation recovery unit, most of the water in the washing tank exhaust gas is removed by the first separation mechanism. The condensation separation mechanism cools and initially reduces the concentration of the washing tank exhaust gas, solving the problems of high temperature and high water content in the washing tank exhaust gas and alleviating the problem of high instantaneous VOC concentration. The absorption mechanism of the absorption unit physically absorbs the oil in the washing tank exhaust gas, further alleviating the problem of high instantaneous VOC concentration in the washing tank exhaust gas and realizing the recovery of VOC in the washing tank exhaust gas. The washing tank exhaust gas, combustion gas, and oxygen are mixed by the gas mixing mechanism and then transported to the combustion mechanism. The mixed gas is ignited by the ignition mechanism, and the purified gas is discharged into the atmosphere.

[0072] This system adopts a PLC (Programmable Logic Controller) as its core automatic control system, integrating a distributed control system (DCS) to achieve remote monitoring and operation. Its main functions include:

[0073] Parameter monitoring: Real-time system operation data is collected by sensors (temperature, pressure, flow rate, VOCs concentration, liquid level, oxygen content, etc.) deployed in each unit, with a sampling frequency ≥1Hz and data transmission delay ≤1 second.

[0074] Dynamic control: Based on monitoring data, the system automatically adjusts the operating parameters of key equipment, such as the cooling capacity of the refrigeration unit, the flow rate of the absorbent, and the air-fuel ratio of the combustion system, ensuring that the system is always in optimal operating condition. For example, when the concentration of VOCs in the exhaust gas rises sharply, the system can quickly increase the absorbent flow rate and the oxidant supply to prevent the combustion temperature from becoming too high.

[0075] Interlocking control: Multiple interlocking protection logics are set up, such as automatically reducing the supply of combustion-supporting fuel and increasing the oxidant flow when the combustion temperature exceeds 1100℃; immediately cutting off the exhaust gas supply and starting nitrogen purging when the VOCs concentration exceeds 25% of the lower explosive limit; and closing the corresponding gas shut-off valve when the fan fails to shut down.

[0076] Human-computer interaction: Human-computer interaction is achieved through touch screen and host computer software. Operators can view the system operation status, historical data trends, alarm records, etc. in real time, and can manually intervene in the system operation when authorized.

[0077] This invention solves the problems of poor stability, high operating costs, high treatment risks, and difficulty in achieving emission standards in existing waste gas treatment devices for washing tanks, and achieves safe, efficient, and stable emission of waste gas from washing tanks in compliance with emission standards.

[0078] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0079] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A high-efficiency stable recovery treatment system for washing tank exhaust gas, characterized by comprising: The application relates to a condensation recovery unit, an absorption unit and a combustion unit which are sequentially connected. The condensation recovery unit comprises a first separation mechanism, and the first separation mechanism is connected with a condensation separation mechanism. The absorption unit comprises an absorption mechanism, and the absorption mechanism is connected with the condensation separation mechanism. The combustion unit comprises a gas mixing mechanism, and the gas mixing mechanism is connected with the absorption mechanism; the gas mixing mechanism is connected with a combustion mechanism, and the combustion mechanism is provided with an ignition mechanism. The first separation mechanism comprises a filter separator (101), the filter separator (101) is connected with a washing tank station vacuum pump, the filter separator (101) is connected with an oil temporary storage tank (104), and the filter separator (101) is connected with the condensation separation mechanism.

2. The system according to claim 1, wherein: The condensation separation mechanism comprises a washing tank waste gas condensation liquid separator (103), the washing tank waste gas condensation liquid separator (103) is connected with the filter separator (101), the washing tank waste gas condensation liquid separator (103) is connected with the oil temporary storage tank (104), the washing tank waste gas condensation liquid separator (103) is connected with the absorption mechanism, and the washing tank waste gas condensation liquid separator (103) is connected with a refrigerating unit (105).

3. The system of claim 2, wherein: The absorption mechanism comprises an absorption tower (204), a top gas outlet of the absorption tower (204) is connected with a separator (205), the separator (205) is connected with the gas mixing mechanism, a top liquid inlet of the absorption tower (204) is connected with an absorption lean oil pump (202-2), the absorption lean oil pump (202-2) is connected with an external absorption lean oil supply device, the absorption lean oil pump (202-2) is connected with a lean oil cooler (203), a side wall gas inlet of the absorption tower (204) is connected with the washing tank waste gas condensation liquid separator (103), a side wall liquid inlet of the absorption tower (204) is connected with an oil delivery pump (106), the oil delivery pump (106) is connected with the oil temporary storage tank (104), and a bottom liquid outlet of the absorption tower (204) is connected with an absorption rich oil pump (202-1).

4. The system of claim 3, wherein: The gas mixing mechanism comprises a turbulent flow mixing chamber (309), a bottom end of the turbulent flow mixing chamber (309) is connected with an oxidation fan (302) and the separator (205), an external combustion-supporting gas supply device is connected to a side wall of the turbulent flow mixing chamber (309), and a top end of the turbulent flow mixing chamber (309) is connected with the combustion mechanism.

5. The system of claim 4, wherein: A combustion-supporting gas pressure regulating valve (304) and a combustion-supporting gas cut-off valve (305) are arranged between the turbulent flow mixing chamber (309) and the external combustion-supporting gas supply device.

6. The system of claim 5, wherein: A third waste gas fan (301) and a waste gas cut-off valve (303) are arranged between the turbulent flow mixing chamber (309) and the separator (205).

7. The system of claim 5, wherein: The combustion mechanism comprises a high-temperature-resistant chimney (311), a metal fiber surface burner (310) is arranged at a bottom end of the high-temperature-resistant chimney (311), and the bottom end of the high-temperature-resistant chimney (311) is connected with the turbulent flow mixing chamber (309).

8. The system of claim 5, wherein: ​ 9. The system of claim 8, wherein: The ignition mechanism comprises an ignition gun (308), an ignition end of the ignition gun (308) is arranged corresponding to the metal fiber surface burner (310), and an air inlet end of the ignition gun (308) is arranged with an ignition air pressure regulating valve (306) and an ignition air cut-off valve (307).

10. The system of claim 4, wherein: The sidewall air inlet of the absorption tower (204) is communicated with other waste gas air inlet devices.

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