A station VOCs gas zero-emission centralized recovery device and process method

Abstract

This invention discloses a centralized VOCs gas recovery device and process for zero emissions at a station, belonging to the field of ecological governance technology. The specific steps of the process are as follows: I. Before gas recovery, the water cooling system and hydraulic system are debugged and safety parameters are set, while the status of each valve is checked; II. The triethylene glycol tail gas and VOCs gas in the venting main are collected and pretreated, and the pretreated triethylene glycol tail gas and VOCs gas are pressurized in one stage. This invention ensures a non-combustion state, reduces the workload of on-site installation and maintenance, simplifies the overall recovery process, eliminates the need for the high power consumption and complex frequency conversion control of conventional reciprocating machines and screw compressors, reduces energy loss, reduces operating costs, and comprehensively avoids risks such as equipment overpressure, gas backflow, and flare backfire, ensuring system safety and stable recovery efficiency. Therefore, we propose a centralized VOCs gas recovery device and process for zero emissions at a station.

Description

Technical Field

[0001] This invention relates to the field of ecological governance technology, and in particular to a centralized VOCs gas recovery device and process for zero emissions at a station. Background Technology

[0002] Volatile organic compounds (VOCs) are organic compounds with a saturated vapor pressure greater than 70 Pa at room temperature and a boiling point below 260℃ at atmospheric pressure. They are not only important precursors to urban haze and photochemical smog, but also possess toxicity, irritant properties, and carcinogenicity, posing significant threats to the atmospheric environment and human health. In gas field stations, VOCs mainly originate from the tail gas of the distillation column of the triethylene glycol dehydration unit, flash vapor from the flash tank of the triethylene glycol dehydration unit, flash vapor from the produced fluid storage tank, air leaks from valves within the station, air releases during station venting and unblocking operations, and air releases from pipelines and equipment during station shutdown and maintenance. Traditional treatment methods mostly involve venting through flare combustion (the main flame and continuous lamps of the flare burn continuously, producing greenhouse gases) or direct cold emissions (in some stations, due to open flares and lack of metering facilities, daily venting cannot be controlled), which wastes natural gas resources and does not meet environmental protection requirements. Existing VOCs recovery technologies have significant limitations: ANG adsorption natural gas technology lacks large-scale available gas cylinders and is unsuitable for station operating conditions; GTL natural gas to oil technology is complex, costly, and has limited industrial capacity; LNG liquefaction technology requires numerous equipment, has a complex process, occupies a large area, and has a long recovery time; conventional compression recovery technology requires multiple decentralized units to process different VOCs gas sources separately, and relies on high-power electricity and complex frequency conversion control, resulting in high energy consumption, poor adaptability, and difficulty in matching the "low flow, low pressure, and discontinuous" operating conditions of VOCs in stations.

[0003] Existing centralized VOCs gas zero-emission recovery devices and processes at stations cannot guarantee a combustion-free state, increasing the workload of on-site installation and maintenance. The overall recovery process is complex, requiring high-power electrical energy consumption from conventional reciprocating machines and screw compressors, as well as complex frequency conversion control, which increases energy loss, operating costs, and recovery efficiency. Therefore, we propose a centralized VOCs gas zero-emission recovery device and process for stations. Summary of the Invention

[0004] The purpose of this invention is to address the deficiencies in the existing technology by proposing a centralized VOCs gas zero-emission recovery device and process method for stations.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A centralized VOCs gas recovery process with zero emissions at a station, the specific steps of which are as follows: Ⅰ. Before gas recovery, debug the water cooling system and hydraulic system, set safety parameters, and check the status of each valve; II. Collect and pre-treat the triethylene glycol tail gas and VOCs gas in the venting manifold, and then perform a first-stage pressurization on the pre-treated triethylene glycol tail gas and VOCs gas. III. Mix the various gases after primary pressurization, and perform real-time safety monitoring and venting, while simultaneously cooling and controlling the temperature of the mixed gas; IV. The mixed gas is pressurized in two stages, and the pressurized mixed gas is pre-treated for external transmission before being connected to the station's gathering and transmission pipeline network.

[0006] As a further aspect of the present invention, the specific steps for debugging the water cooling system and hydraulic system, setting safety parameters, and checking the status of each valve in step I are as follows: S1.1: Check that there are no leaks in the connecting pipelines of the water cooling system and the triethylene glycol tail gas recovery control valve group, the triethylene glycol tail gas booster water-cooled hydraulic cylinder, the vent main recovery gas booster water-cooled hydraulic cylinder, the mixed gas interstage control valve group, the mixed gas secondary booster water-cooled hydraulic cylinder, and the mixed gas external output control valve group. Then start the water cooling system, adjust the flow rate and temperature of the circulating cooling water, and run the water cooling system for 10 to 15 minutes. Check the cooling effect through the temperature monitoring instruments of each component, and confirm that the temperature of each connected component can be stably controlled within the process allowable range, without overheating or insufficient cooling. S1.2: Add hydraulic oil of the correct specifications to the hydraulic system, check that the oil level and pressure gauge readings are normal, and that there is no oil leakage or seepage. Check and confirm the connection lines between the hydraulic system and the triethylene glycol exhaust gas booster water-cooled hydraulic cylinder, the vent main recovery gas booster water-cooled hydraulic cylinder, and the mixed gas secondary booster water-cooled hydraulic cylinder. Start the hydraulic system and control the hydraulic oil to drive the hydraulic cylinders of each booster cylinder to reciprocate. Observe whether the cylinder piston movement is smooth and without jamming. Then monitor the power output pressure through the oil pressure gauge to ensure that the reciprocating frequency matches the boosting demand. After that, keep each booster cylinder in a no-air state and run the hydraulic system unloaded for 5 to 8 minutes to verify the linkage and coordination between the hydraulic cylinder and the piston. If there is no abnormal noise or vibration, confirm that the power circulation system is functioning normally. S1.3: Initialize and set the pressure relief values ​​of the constant pressure valve, electro-hydraulic quick-opening butterfly valve and anti-arch type rupture disc respectively, and dynamically adjust them according to the actual venting pressure in the station. Then check that ball valve one and ball valve two before and after the anti-arch type rupture disc are in the closed state, check whether the flame arrester is installed firmly and without blockage, and then perform interlocking debugging of the pressure transmitter at the inlet of the venting main venting control valve group and the electro-hydraulic quick-opening butterfly valve. S1.4: Position the electric ball valve 1 of the triethylene glycol tail gas recovery control valve group, the electric ball valve 2 of the vent main recovery gas control valve group, and the electric ball valve 3 of the mixed gas export control valve group that need to be controlled. Manually or through the control system, adjust all the above electric ball valves to the closed state. Then, remotely trigger the opening and closing actions of each electric ball valve through the control system to verify that the valve response is flexible and without jamming. S1.5: After completing the commissioning, reconfirm that the circulating water flow and temperature of the water cooling system, the oil pressure of the hydraulic system, and the pressure setting value of the venting main control valve group all meet the process requirements. Check that the displays of each pressure transmitter, temperature transmitter, and flow meter are normal and there are no fault alarms. Then, switch the system to standby mode through the control system.

[0007] As a further aspect of the present invention, the specific steps for collecting and pretreating the triethylene glycol tail gas and VOCs gas in the venting main in step II are as follows: S2.1: Open the electric ball valve one in the triethylene glycol tail gas recovery control valve group, so that the triethylene glycol tail gas generated in the station flows through the filter one in the triethylene glycol tail gas recovery control valve group along the dedicated pipeline. The filter intercepts the mechanical impurities and large particulate pollutants contained in the triethylene glycol tail gas. The filtered triethylene glycol tail gas enters the water-cooled heat exchanger in the triethylene glycol tail gas recovery control valve group. Through the heat exchange between the circulating cooling water and the tail gas, the tail gas temperature is reduced to 50-70℃. S2.2: The pressure and temperature of the tail gas before and after cooling are monitored in real time by the pressure transmitter and temperature transmitter instrument valve group in the triethylene glycol tail gas recovery control valve group. Then, the cooled gas-liquid two-phase triethylene glycol tail gas is passed through the gas-liquid two-phase flow meter in the triethylene glycol tail gas recovery control valve group to accurately measure the gas phase and liquid phase flow of the triethylene glycol tail gas. S2.3: Open the electric ball valve two in the vent main recovery gas control valve group to allow the VOCs gas in the vent main to enter the pretreatment system. At the same time, the VOCs gas in the vent main flows through the filter two in the vent main recovery gas control valve group and filters out the condensate oil and mechanical impurities contained in the VOCs gas. S2.4: The pressure and temperature of the VOCs gas entering the pretreatment system are monitored in real time by the pressure transmitter and temperature transmitter instrument valve group in the vent main recovery gas control valve group. The VOCs gas in the vent main after filtration and parameter monitoring flows through the Barrel flow meter in the vent main recovery gas control valve group to accurately measure the VOCs gas.

[0008] As a further aspect of the present invention, the specific steps of the first-stage booster described in step II are as follows: S3.1: The pretreated triethylene glycol exhaust gas is introduced into the single-stage booster cylinder cavity of the triethylene glycol exhaust gas booster water-cooled hydraulic cylinder through a dedicated pipeline. At the same time, during the connection process, the pressure transmitter of the front-end pretreatment stage monitors the intake pressure in real time, starts the hydraulic system, delivers hydraulic oil to the hydraulic cylinder of the triethylene glycol exhaust gas booster water-cooled hydraulic cylinder, and drives the hydraulic cylinder piston to reciprocate. The piston mechanically compresses the triethylene glycol exhaust gas in the single-stage booster cylinder cavity. S3.2: During the compression process, the water cooling heat exchange system of the triethylene glycol tail gas booster water-cooled hydraulic cylinder is simultaneously activated. The circulating cooling water continuously absorbs the heat generated during the gas compression process through the heat exchange channel of the cylinder until the first stage of boosting is completed. S3.3: The VOCs gas from the pretreated venting manifold is introduced into the single-stage booster cylinder of the venting manifold recovery gas booster water-cooled hydraulic cylinder through a pipeline adapted for low flow rate and low velocity conditions. When connected, the opening of the inlet valve is adjusted in real time based on the real-time data of the Barrel flow meter to ensure that the gas enters the cavity evenly. S3.4: The hydraulic system supplies hydraulic oil to the hydraulic cylinder of the gas recovery booster water-cooled hydraulic cylinder in the vent manifold, and drives the piston of the hydraulic cylinder to reciprocate. This, in turn, drives the piston in the single-stage booster cylinder to perform reciprocating compression action synchronously. At the same time, during the compression process, the water cooling heat exchange system of the gas recovery booster water-cooled hydraulic cylinder in the vent manifold continues to operate. The circulating cooling water absorbs the heat generated by compression and controls the gas temperature in the single-stage booster cylinder until the first stage of boosting is completed.

[0009] As a further aspect of the present invention, the specific steps of mixing the various gases after primary pressurization in step III, and performing real-time safety monitoring and venting, while simultaneously cooling and controlling the temperature of the mixed gas, are as follows: S4.1: The triethylene glycol tail gas and VOCs gas that have completed the first stage of pressurization are connected to the same flow channel through a dedicated confluence pipeline for preliminary mixing of the two types of gases. The uniformly mixed gas is then introduced into the water-cooled heat exchanger of the interstage control valve group for the mixed gas. The mixed gas exchanges heat with the circulating cooling water, absorbing the residual heat of the mixed gas during the first stage of pressurization and the heat generated during the mixing process, so that the temperature of the mixed gas is reduced to the process range suitable for the second stage of pressurization. S4.2: The pressure transmitter continuously collects the current pressure value of the mixed gas and determines whether the pressure is within the initial pressure range allowed by the secondary boosting. If the pressure is lower than the preset threshold, it is fed back to the front-end primary boosting system and the parameters are adjusted. If the pressure is higher than the preset threshold, the subsequent safety relief mechanism is triggered. The temperature of the mixed gas after cooling is recorded in real time by the temperature transmitter to evaluate whether the water cooling effect meets the standard. If the temperature exceeds the preset range, the circulating water flow or temperature of the water cooling system is adjusted until the temperature of the mixed gas meets the requirements. S4.3: When the safety relief mechanism is triggered, the safety relief valve group of the interstage control valve group of the mixed gas automatically opens and safely relieves the pressure of the overpressure part of the mixed gas through a dedicated relief pipeline until the pressure of the mixed gas drops to within the preset safe range. Then, the safety relief valve group automatically closes and terminates the relief.

[0010] As a further aspect of the present invention, the specific steps of step IV, which involves two-stage pressurization of the gas mixture and pre-treatment of the pressurized gas mixture for external transport, are as follows: S5.1: The mixed gas, which has been cooled between stages and meets the pressure and temperature standards, is introduced into the single-stage booster cylinder cavity of the two-stage booster water-cooled hydraulic cylinder through a dedicated pipeline. The pressure transmitter of the mixed gas interstage control valve group confirms that the mixed gas pressure is stable, and the hydraulic system is started to deliver hydraulic oil with stable pressure to the hydraulic cylinder of the two-stage booster water-cooled hydraulic cylinder. S5.2: Hydraulic oil drives the piston of the hydraulic cylinder to reciprocate, and simultaneously drives the piston in the single-stage booster cylinder to reciprocate in the same direction. The piston mechanically compresses the gas mixture in the cavity, gradually reducing the gas volume. During the compression process, the water cooling heat exchange system of the single-stage booster cylinder is activated simultaneously, and the circulating cooling water continuously absorbs the heat generated by compression through the cylinder heat exchange channel. S5.3: The pressure of the mixed gas after pressurization is monitored in real time by the pressure transmitter at the outlet of the two-stage pressurization water-cooled hydraulic cylinder. If the pressure does not reach the preset standard, the power output of the hydraulic system is adjusted. If the pressure exceeds the preset standard, the local safety relief valve is triggered for adjustment until the pressure stabilizes within the range of the gathering and transmission pipeline network. S5.4: The mixed gas after secondary pressurization is introduced into the water-cooled heat exchanger of the mixed gas output control valve group. The mixed gas is finally cooled by circulating cooling water. During the cooling process, the outlet temperature is monitored in real time by a temperature transmitter. If the temperature exceeds the preset standard, the circulating water flow rate of the water cooling system is adjusted until the temperature meets the transmission temperature requirements of the station's collection and transmission pipeline network. S5.5: Using the pressure transmitter and temperature transmitter instrument valve group of the mixed gas export control valve group, the pressure and temperature of the mixed gas after final cooling are collected in real time. If the pressure is detected to exceed the preset standard, the safety relief valve group is automatically opened to safely release the overpressure part of the mixed gas through a dedicated pipeline until the pressure drops to the standard range and then automatically closes. S5.6: Cooled and qualified mixed gas flows into the gas flow meter of the mixed gas export control valve group through the pipeline, and the export flow of the mixed gas is accurately measured. At the same time, the mixed gas flows through the check valve after measurement. After the check valve is checked and found to be correct, the electric ball valve of the mixed gas export control valve group is confirmed to be in the closed state. After all export parameters have reached the preset standards, the electric ball valve is opened to export.

[0011] As a further aspect of the present invention, the specific steps of step IV, which involves connecting the pretreated mixed gas into the station's gathering and transmission pipeline network, are as follows: S6.1: After confirming that all parameters of the mixed gas export pretreatment and metering process meet the requirements, the electric ball valve three of the mixed gas export control valve group is opened remotely or on-site through the control system, and the valve opening is slowly adjusted. After the electric ball valve three is opened, the mixed gas is connected to the station's gathering and transmission network through a dedicated export pipeline, and enters the subsequent natural gas processing system together with the raw gas in the pipeline network. S6.2: After the mixed gas is stably connected to the gathering and transmission pipeline network, turn off the fuel supply to the flare lamp, extinguish the lamp, close the control valve of the flare main combustion system, ensure that the flare is not in a combustion state, and at the same time check that the connection valve between the vent flare and the vent main is closed.

[0012] A centralized VOCs gas zero-emission recovery device for a station includes a venting main control valve group, a triethylene glycol tail gas recovery control valve group, a triethylene glycol tail gas booster water-cooled hydraulic cylinder, a venting main recovery gas control valve group, a venting main recovery gas booster water-cooled hydraulic cylinder, a mixed gas interstage control valve group, a mixed gas two-stage booster water-cooled hydraulic cylinder, a mixed gas external transmission control valve group, a water cooling system, and a hydraulic system. The venting main control valve group includes a pressure transmitter, ball valve one, ball valve two, constant pressure valve, electro-hydraulic quick-opening butterfly valve, rupture disc and flame arrester. The triethylene glycol tail gas recovery control valve group includes a filter, an electric ball valve, a water-cooled heat exchanger, a pressure transmitter and temperature transmitter instrument valve group one, a pressure transmitter and temperature transmitter instrument valve group two, and a gas-liquid two-phase flow meter. The triethylene glycol exhaust gas booster water-cooled hydraulic cylinder includes a single-stage booster cylinder, a hydraulic cylinder, and a water-cooled heat exchange system. The vent main recovery gas control valve group includes filter two, electric ball valve two, pressure transmitter and temperature transmitter instrument valve group three, and a bar-type flow meter; The venting manifold recovers gas pressurization water-cooled hydraulic cylinder includes a single-stage pressurization cylinder, a hydraulic cylinder, and a water-cooled heat exchange system. The mixed gas stage control valve group includes a water-cooled heat exchanger II, a safety relief valve group I, a pressure transmitter and temperature transmitter instrument valve group IV, and a pressure transmitter and temperature transmitter instrument valve group V. The mixed gas two-stage booster water-cooled hydraulic cylinder includes a single-stage booster cylinder, a hydraulic cylinder, and a water-cooled heat exchange system. The mixed gas export control valve group includes a pressure transmitter and a temperature transmitter instrument valve group six, a safety relief valve group, a water-cooled heat exchanger three, a gas flow meter, a check valve, and an electric ball valve three.

[0013] As a further embodiment of the present invention, the venting main control valve group is installed on the venting main upstream of the venting flare, replacing the venting main of the same length as part of the venting main; the outlet of the triethylene glycol tail gas recovery control valve group is connected to the triethylene glycol tail gas booster water-cooled hydraulic cylinder; the venting main recovery gas control valve group is connected to the venting main recovery gas booster water-cooled hydraulic cylinder; after the triethylene glycol tail gas booster water-cooled hydraulic cylinder and the venting main recovery gas booster water-cooled hydraulic cylinder outlet are mixed, they are connected to the mixed gas secondary booster water-cooled hydraulic cylinder via the mixed gas interstage control valve group, and then connected to the station's gathering and transmission pipeline network via the mixed gas external transmission control valve group; The pressure regulating valve, electro-hydraulic quick-opening butterfly valve, and rupture disc together form a safety system with three-stage pressure relief capability. The pressure regulating valve is the first-stage pressure relief safety system with the lowest pressure setting, set at 0.2 MPa. The electro-hydraulic quick-opening butterfly valve is the second-stage pressure relief safety system with a higher pressure setting, set at 0.25 MPa. The rupture disc is the third-stage pressure relief safety system with a higher pressure setting than both the pressure regulating valve and the electro-hydraulic quick-opening butterfly valve, set at 0.35 MPa.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: The centralized VOCs zero-emission recovery process at this station first checks for leaks in all water-cooled and hydraulic pipelines. The water-cooling system is then started and temperature control confirmed to be normal. Hydraulic oil is added to the hydraulic system, and the smooth reciprocating motion of the booster cylinder piston is verified. Subsequently, the pressure regulating valve, electro-hydraulic butterfly valve, and rupture disc are set and interlocked, confirming that each valve opens and closes flexibly. During operation, triethylene glycol tail gas and VOCs from the vent main are filtered, cooled, and subjected to pressure and temperature monitoring and flow metering before entering their respective single-stage booster water-cooled hydraulic cylinders. After compression and cooling, the mixture is combined and enters the secondary booster and water-cooled heat exchange stage, ensuring that pressure and temperature meet requirements and triggering safety venting if necessary. Finally, the mixed gas is cooled by the external transmission control valve group, metered, and checked by the check valve before being connected to the collection and transmission network. Once the system is stable, shut off the flare lamp and main combustion system to ensure a non-combustion state, reducing on-site installation and maintenance workload, simplifying the overall recycling process, eliminating the need for high-power electrical consumption and complex frequency conversion control of conventional reciprocating machines and screw compressors, reducing energy loss and operating costs, comprehensively avoiding risks such as equipment overpressure, gas backflow, and flare backfire, ensuring system safety, and ensuring stable recycling efficiency. Attached Figure Description

[0015] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0016] Figure 1 This is a flowchart of a centralized VOCs gas zero-emission recovery process method for stations proposed in this invention; Figure 2 This is a block diagram of a centralized VOCs gas zero-emission recovery device for stations proposed in this invention; Figure 3 This is a schematic diagram of the structure of a centralized VOCs gas zero-emission recovery device for a station proposed in this invention; In the diagram: 1. Vent manifold venting control valve assembly; 2. Triethylene glycol tail gas recovery control valve assembly; 3. Triethylene glycol tail gas booster water-cooled hydraulic cylinder; 4. Vent manifold recovery gas control valve assembly; 5. Vent manifold recovery gas booster water-cooled hydraulic cylinder; 6. Mixed gas interstage control valve assembly; 7. Mixed gas two-stage booster water-cooled hydraulic cylinder; 8. Mixed gas export control valve assembly; 9. Water cooling system; 10. Hydraulic system; 101. Pressure transmitter; 102. Ball valve one; 103. Rupture disc; 104. Pressure regulating valve; 105. Electro-hydraulic quick-opening butterfly valve; 106. Ball valve two; 107. Flame arrester; 201. Filter 1; 202. Electric ball valve 1; 203. Pressure transmitter and temperature transmitter instrument valve assembly 1; 204. Water-cooled heat exchanger 1; 205. Pressure transmitter and temperature transmitter instrument valve assembly 2; 206. Gas-liquid two-phase flow meter; 207. Triethylene glycol tail gas booster water-cooled hydraulic cylinder; 301. Filter II; 302. Electric Ball Valve II; 303. Pressure Transmitter and Temperature Transmitter Instrument Valve Assembly III; 304. Barrel Flow Meter; 305. Vent Main Recovered Gas Booster Water-Cooled Hydraulic Cylinder; 506. Electric Ball Valve III; 401. Instrument valve assembly four for pressure and temperature transmitters; 402. Water-cooled heat exchanger two; 403. Instrument valve assembly five for pressure and temperature transmitters; 404. Safety relief valve assembly one; 405. Two-stage pressurized water-cooled hydraulic cylinder for mixed gas. 501. Pressure transmitter and temperature transmitter instrument valve assembly six; 503. Water-cooled heat exchanger three; 502. Safety relief valve assembly two; 504. Gas flow meter; 505. Check valve. Detailed Implementation

[0017] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0018] Example 1: Refer to Figure 1 This embodiment discloses a centralized VOCs gas zero-emission recovery process for a station. The specific steps of the process are as follows: Before gas recovery, the water cooling system and hydraulic system are tested and safety parameters are set, while the status of each valve is checked.

[0019] Specifically, check that the connecting pipelines of the water cooling system and the triethylene glycol tail gas recovery control valve assembly, the triethylene glycol tail gas booster water-cooled hydraulic cylinder, the vent main recovery gas booster water-cooled hydraulic cylinder, the interstage control valve assembly, the secondary booster water-cooled hydraulic cylinder, and the external control valve assembly are leak-free. Then, start the water cooling system, adjust the flow rate and temperature of the circulating cooling water, and run the system for 10-15 minutes. Use temperature monitoring instruments on each component to check the cooling effect and confirm that the temperature of each connected component can be stably controlled within the allowable range of the process, without overheating or insufficient cooling. Add fuel to the hydraulic system. Fill with hydraulic oil of the correct specifications, check the oil level and pressure gauge readings to ensure they are normal, and confirm there are no leaks or seepage. Inspect and confirm the connection lines between the hydraulic system and the triethylene glycol exhaust gas booster water-cooled hydraulic cylinder, the vent main recovery gas booster water-cooled hydraulic cylinder, and the mixed-gas secondary booster water-cooled hydraulic cylinder. Start the hydraulic system and control the hydraulic oil to drive the hydraulic cylinders of each booster cylinder in reciprocating motion. Observe whether the cylinder piston movement is smooth and without jamming. Then, monitor the power output pressure using the pressure gauge to ensure it is stable and that the reciprocating frequency matches the boosting demand. Afterward, keep each booster cylinder in a no-air state and run the hydraulic system unloaded for 5 minutes. After approximately 8 minutes, the linkage and coordination between the hydraulic cylinder and piston were verified. No abnormal noise or vibration was observed, confirming the normal function of the power circulation system. The pressure setting of the constant pressure valve, electro-hydraulic quick-opening butterfly valve, and anti-arch type rupture disc were initialized and dynamically adjusted according to the actual venting pressure at the station. Then, it was checked that ball valves one and two before and after the anti-arch type rupture disc were in the closed state. The flame arrester was checked for secure installation and no blockage. Next, the pressure transmitter at the inlet of the venting main control valve group was interlocked with the electro-hydraulic quick-opening butterfly valve for testing. The electric ball valve one of the triethylene glycol tail gas recovery control valve group to be controlled and the venting main were then located. The electric ball valves 2 of the recovery gas control valve group and 3 of the mixed gas export control valve group were manually or through the control system adjusted to the closed state. Then, the opening and closing actions of each electric ball valve were remotely triggered through the control system to verify that the valve response was flexible and without jamming. After the debugging was completed, it was confirmed again that the circulating water flow and temperature of the water cooling system, the oil pressure of the hydraulic system, and the pressure set value of the venting main pipe relief control valve group all met the process requirements. The displays of each pressure transmitter, temperature transmitter, and flow meter were checked to be normal and there were no fault alarms. Finally, the system was switched to standby mode through the control system.

[0020] The triethylene glycol tail gas and VOCs gas in the venting manifold are collected and pretreated, and the pretreated triethylene glycol tail gas and VOCs gas are pressurized in one stage.

[0021] Specifically, the electric ball valve one in the triethylene glycol (TED) tail gas recovery control valve group is opened, allowing the TED tail gas generated in the station to flow along a dedicated pipeline through filter one in the TED tail gas recovery control valve group. The filter removes mechanical impurities and large particulate pollutants contained in the TED tail gas. The filtered TED tail gas then enters the water-cooled heat exchanger in the TED tail gas recovery control valve group. Through heat exchange between the circulating cooling water and the tail gas, the tail gas temperature is reduced to 50-70°C. The pressure and temperature of the tail gas before and after cooling are monitored in real time by the pressure transmitter and temperature transmitter instrument valve group in the TED tail gas recovery control valve group. Finally, the cooled gas-liquid two-phase TED tail gas is flowed through the gas-liquid two-phase flow meter in the TED tail gas recovery control valve group. To accurately measure the gas and liquid phase flow rates of triethylene glycol tail gas, the electric ball valve two in the vent main recovery gas control valve group is opened, allowing the VOCs gas in the vent main to enter the pretreatment system. At the same time, the VOCs gas in the vent main flows through filter two in the vent main recovery gas control valve group, filtering out condensate oil and mechanical impurities contained in the VOCs gas. The pressure and temperature of the VOCs gas entering the pretreatment system are monitored in real time by the pressure transmitter and temperature transmitter instrument valve group in the vent main recovery gas control valve group. The filtered and parameter-monitored VOCs gas in the vent main flows through the Barrel flow meter in the vent main recovery gas control valve group for accurate measurement of VOCs gas.

[0022] Specifically, the pretreated triethylene glycol (TED) exhaust gas is introduced into the single-stage booster cylinder chamber of the TED exhaust gas booster water-cooled hydraulic cylinder through a dedicated pipeline. Simultaneously, during the connection process, the intake pressure is monitored in real time by a pressure transmitter in the pretreatment stage. The hydraulic system is then activated to supply hydraulic oil to the hydraulic cylinder of the TED exhaust gas booster water-cooled hydraulic cylinder, driving the piston to reciprocate. The piston mechanically compresses the TED exhaust gas within the single-stage booster cylinder chamber. During compression, the water-cooled heat exchange system of the TED exhaust gas booster water-cooled hydraulic cylinder is simultaneously activated. Circulating cooling water continuously absorbs the heat generated during gas compression through the cylinder's heat exchange channels until the first stage of boosting is completed, and the pretreated exhaust gas is then... VOCs gas from the vent manifold is introduced into the single-stage booster cylinder of the vent manifold gas recovery booster water-cooled hydraulic cylinder through a pipeline adapted for low flow rate and low velocity conditions. Real-time data from a Barrel flow meter is used to adjust the inlet valve opening, ensuring uniform gas entry into the chamber. The hydraulic system supplies hydraulic oil to the hydraulic cylinder of the vent manifold gas recovery booster water-cooled hydraulic cylinder, driving the piston to reciprocate. This, in turn, drives the piston in the single-stage booster cylinder to synchronously perform reciprocating compression. Simultaneously, during compression, the water-cooled heat exchange system of the vent manifold gas recovery booster water-cooled hydraulic cylinder continuously operates, circulating cooling water to absorb the heat generated by compression, controlling the gas temperature within the single-stage booster cylinder until the first stage of boosting is completed.

[0023] The various gases after primary pressurization are mixed, and real-time safety monitoring and venting are performed, while the mixed gas is cooled and its temperature controlled.

[0024] Specifically, the triethylene glycol tail gas and VOCs gas, after completing the first-stage pressurization, are connected to the same flow channel through a dedicated confluence pipeline for initial mixing of the two gases. The uniformly mixed gas is then introduced into the water-cooled heat exchanger of the interstage control valve group. Circulating cooling water exchanges heat with the mixed gas, absorbing the residual heat from the first-stage pressurization process and the heat generated during mixing, thus lowering the temperature of the mixed gas to a range suitable for the second-stage pressurization process. A pressure transmitter continuously collects the current pressure value of the mixed gas to determine whether the pressure is within the allowable initial pressure range for the second-stage pressurization. If the pressure is lower than a preset threshold... The system then feeds back to the front-end primary booster system and adjusts the parameters. If the pressure exceeds the preset threshold, the subsequent safety relief mechanism is triggered. The temperature of the mixed gas after cooling is recorded in real time by a temperature transmitter to assess whether the water cooling effect meets the standard. If the temperature exceeds the preset range, the circulating water flow or temperature of the water cooling system is adjusted until the temperature of the mixed gas meets the requirements. When the safety relief mechanism is triggered, the safety relief valve group of the mixed gas interstage control valve group automatically opens and safely relieves the pressure of the overpressured mixed gas through a dedicated relief pipeline until the pressure of the mixed gas drops to within the preset safe range. The safety relief valve group then automatically closes, terminating the relief.

[0025] The gas mixture is pressurized in two stages, and the pressurized gas mixture is pre-treated for external transmission before being connected to the station's gas collection and transmission network.

[0026] Specifically, the mixed gas, after interstage cooling and reaching the required pressure and temperature, is introduced into the single-stage booster cylinder chamber of the two-stage booster water-cooled hydraulic cylinder through a dedicated pipeline. The pressure transmitter of the interstage control valve group confirms stable mixed gas pressure. The hydraulic system is then activated, supplying hydraulic oil at a stable pressure to the hydraulic cylinder of the two-stage booster water-cooled hydraulic cylinder. The hydraulic oil drives the piston in the hydraulic cylinder to reciprocate, simultaneously driving the piston in the single-stage booster cylinder to reciprocate in the same direction. The piston mechanically compresses the mixed gas within the chamber, gradually reducing its volume. During compression, the water-cooled heat exchange system of the single-stage booster cylinder is simultaneously activated. Circulating cooling water continuously absorbs the heat generated by compression through the cylinder's heat exchange channel. The pressure transmitter at the outlet of the two-stage booster water-cooled hydraulic cylinder monitors the boosted mixed gas pressure in real time. If the pressure does not reach the preset standard, the hydraulic system's power output is adjusted; if the pressure exceeds the preset standard, a local safety relief valve is triggered for adjustment until the pressure stabilizes within the range compatible with the gathering and transmission network. The pressurized mixed gas is introduced into the water-cooled heat exchanger of the mixed gas export control valve group. The mixed gas is finally cooled by circulating cooling water. During the cooling process, the outlet temperature is monitored in real time by a temperature transmitter. If the temperature exceeds the preset standard, the circulating water flow rate of the water cooling system is adjusted until the temperature meets the transmission temperature requirements of the station's gathering and transmission network. The pressure transmitter and temperature transmitter instrument valve group of the mixed gas export control valve group are used to collect the pressure and temperature of the mixed gas after final cooling in real time. If the pressure is detected to exceed the preset standard, the safety relief valve group is automatically opened to safely release the overpressured part of the mixed gas through a dedicated pipeline until the pressure drops to the standard range and then automatically closes. The cooled and parameter-compliant mixed gas flows into the gas flow meter of the mixed gas export control valve group through the pipeline, and the export flow rate of the mixed gas is accurately measured. At the same time, the mixed gas flows through the check valve after measurement. After the check valve is checked and confirmed to be correct, the electric ball valve of the mixed gas export control valve group is confirmed to be in the closed state. After all export parameters have reached the preset standard, the electric ball valve is opened for export.

[0027] Specifically, after confirming that all parameters in the pretreatment and metering stages of the mixed gas export meet the requirements, the electric ball valve three of the mixed gas export control valve group is opened remotely or on-site via the control system. The valve opening is then slowly adjusted. After the electric ball valve three is opened, the mixed gas enters the station's gathering and transmission network via a dedicated export pipeline, and enters the subsequent natural gas processing system together with the raw gas in the network. After the mixed gas is stably connected to the gathering and transmission network, the fuel supply to the flare lamp is turned off, the lamp is extinguished, and the control valve of the flare main combustion system is closed to ensure that the flare is not in a combustion state. At the same time, it is checked that the connection valve between the vent flare and the vent main is closed.

[0028] Example 2: Refer to Figure 2-3This embodiment discloses a centralized VOCs gas zero-emission recovery device for a station, including a venting main control valve group 1, a triethylene glycol tail gas recovery control valve group 2, a triethylene glycol tail gas booster water-cooled hydraulic cylinder 3, a venting main recovery gas control valve group 4, a venting main recovery gas booster water-cooled hydraulic cylinder 5, a mixed gas interstage control valve group 6, a mixed gas two-stage booster water-cooled hydraulic cylinder 7, a mixed gas external transmission control valve group 8, a water cooling system 9, and a hydraulic system 10; The vent main discharge control valve assembly 1 includes a pressure transmitter 101, ball valve 102, ball valve 2 106, pressure regulating valve 104, electro-hydraulic quick-opening butterfly valve 105, rupture disc 103, and flame arrester 107; the vent main recovery gas control valve assembly 4 includes a filter 2 301, electric ball valve 2 302, pressure transmitter and temperature transmitter instrument valve assembly 3 303, and a Barrel flow meter 304; the vent main recovery gas booster water-cooled hydraulic cylinder 5 includes a single-stage booster cylinder, a hydraulic cylinder, and a water-cooled heat exchange system; Triethylene glycol tail gas recovery control valve assembly 2 includes filter 201, electric ball valve 202, water-cooled heat exchanger 204, pressure transmitter and temperature transmitter instrument valve assembly 203, pressure transmitter and temperature transmitter instrument valve assembly 205, and gas-liquid two-phase flow meter 206; triethylene glycol tail gas booster water-cooled hydraulic cylinder 3 includes a single-stage booster cylinder, a hydraulic cylinder, and a water-cooled heat exchange system. The mixed gas stage control valve group 6 includes a water-cooled heat exchanger 2 402, a safety relief valve group 1 404, a pressure transmitter and temperature transmitter instrument valve group 401, and a pressure transmitter and temperature transmitter instrument valve group 5 403; the mixed gas stage booster water-cooled hydraulic cylinder 7 includes a single-stage booster cylinder, a hydraulic cylinder, and a water-cooled heat exchange system; the mixed gas export control valve group 8 includes a pressure transmitter and temperature transmitter instrument valve group 6 501, a safety relief valve group, a water-cooled heat exchanger 3 503, a gas flow meter 504, a check valve 505, and an electric ball valve 3 506.

[0029] It should be noted that the venting main control valve assembly 1 is installed on the venting main upstream of the venting flare, replacing a venting main of equal length as part of the venting main; the outlet of the triethylene glycol tail gas recovery control valve assembly 2 is connected to the triethylene glycol tail gas pressurizing water-cooled hydraulic cylinder 3; the venting main recovery gas control valve assembly 4 is connected to the venting main recovery gas pressurizing water-cooled hydraulic cylinder 5; after the triethylene glycol tail gas pressurizing water-cooled hydraulic cylinder 3 and the venting main recovery gas pressurizing water-cooled hydraulic cylinder 5 are mixed, they are connected to the mixed gas secondary pressurizing water-cooled hydraulic cylinder 7 via the mixed gas interstage control valve assembly 6, and then the mixed gas is output externally. The control valve group 8 is connected to the station's collection and transmission pipeline network; the pressure regulating valve 104, the electro-hydraulic quick-opening butterfly valve, and the rupture disc 103 together form a safety assurance system with three-stage pressure relief capability. Among them, the pressure regulating valve 104 is the first-stage pressure relief safety system with the lowest pressure setting value, set at 0.2 MPa; the electro-hydraulic quick-opening butterfly valve 105 is the second-stage pressure relief safety system with a higher pressure setting than the pressure regulating valve 104, set at 0.25 MPa; and the rupture disc 103 is the third-stage pressure relief safety system with a higher pressure setting than both the pressure regulating valve 104 and the electro-hydraulic quick-opening butterfly valve 105, set at 0.35 MPa.

Claims

1. A station yard VOCs gas zero-emission centralized recovery process method, characterized in that, The specific steps of this process are as follows: Ⅰ. Before gas recovery, debug the water cooling system and hydraulic system, set safety parameters, and check the status of each valve; II. Collect and pre-treat the triethylene glycol tail gas and VOCs gas in the venting manifold, and then perform a first-stage pressurization on the pre-treated triethylene glycol tail gas and VOCs gas. III. Mix the various gases after primary pressurization, and perform real-time safety monitoring and venting, while simultaneously cooling and controlling the temperature of the mixed gas; IV. The mixed gas is pressurized in two stages, and the pressurized mixed gas is pre-treated for external transmission before being connected to the station's gathering and transmission pipeline network.

2. The process for centralized recovery of VOCs gas zero emission at a station yard according to claim 1, characterized in that, The specific steps for debugging the water cooling system and hydraulic system, setting safety parameters, and checking the status of each valve in Step I are as follows: S1.1: Check that there are no leaks in the connecting pipelines of the water cooling system and the triethylene glycol tail gas recovery control valve group, the triethylene glycol tail gas booster water-cooled hydraulic cylinder, the vent main recovery gas booster water-cooled hydraulic cylinder, the mixed gas interstage control valve group, the mixed gas secondary booster water-cooled hydraulic cylinder, and the mixed gas external output control valve group. Then start the water cooling system, adjust the flow rate and temperature of the circulating cooling water, and run the water cooling system for 10 to 15 minutes. Check the cooling effect through the temperature monitoring instruments of each component, and confirm that the temperature of each connected component can be stably controlled within the process allowable range, without overheating or insufficient cooling. S1.2: Add hydraulic oil of the correct specifications to the hydraulic system, check that the oil level and pressure gauge readings are normal, and that there is no oil leakage or seepage. Check and confirm the connection lines between the hydraulic system and the triethylene glycol exhaust gas booster water-cooled hydraulic cylinder, the vent main recovery gas booster water-cooled hydraulic cylinder, and the mixed gas secondary booster water-cooled hydraulic cylinder. Start the hydraulic system and control the hydraulic oil to drive the hydraulic cylinders of each booster cylinder to reciprocate. Observe whether the cylinder piston movement is smooth and without jamming. Then monitor the power output pressure through the oil pressure gauge to ensure that the reciprocating frequency matches the boosting demand. After that, keep each booster cylinder in a no-air state and run the hydraulic system unloaded for 5 to 8 minutes to verify the linkage and coordination between the hydraulic cylinder and the piston. If there is no abnormal noise or vibration, confirm that the power circulation system is functioning normally. S1.3: Initialize and set the pressure relief values ​​of the constant pressure valve, electro-hydraulic quick-opening butterfly valve and anti-arch type rupture disc respectively, and dynamically adjust them according to the actual venting pressure in the station. Then check that ball valve one and ball valve two before and after the anti-arch type rupture disc are in the closed state, check whether the flame arrester is installed firmly and without blockage, and then perform interlocking debugging of the pressure transmitter at the inlet of the venting main venting control valve group and the electro-hydraulic quick-opening butterfly valve. S1.4: Position the electric ball valve 1 of the triethylene glycol tail gas recovery control valve group, the electric ball valve 2 of the vent main recovery gas control valve group, and the electric ball valve 3 of the mixed gas export control valve group that need to be controlled. Manually or through the control system, adjust all the above electric ball valves to the closed state. Then, remotely trigger the opening and closing actions of each electric ball valve through the control system to verify that the valve response is flexible and without jamming. S1.5: After completing the commissioning, reconfirm that the circulating water flow and temperature of the water cooling system, the oil pressure of the hydraulic system, and the pressure setting value of the venting main control valve group all meet the process requirements. Check that the displays of each pressure transmitter, temperature transmitter, and flow meter are normal and there are no fault alarms. Then, switch the system to standby mode through the control system.

3. The process of claim 2, wherein the process is characterized by, The specific steps for collecting and pretreating the triethylene glycol tail gas and VOCs gas in the venting main in step II are as follows: S2.1: Open the electric ball valve one in the triethylene glycol tail gas recovery control valve group, so that the triethylene glycol tail gas generated in the station flows through the filter one in the triethylene glycol tail gas recovery control valve group along the dedicated pipeline. The filter intercepts the mechanical impurities and large particulate pollutants contained in the triethylene glycol tail gas. The filtered triethylene glycol tail gas enters the water-cooled heat exchanger in the triethylene glycol tail gas recovery control valve group. Through the heat exchange between the circulating cooling water and the tail gas, the tail gas temperature is reduced to 50-70℃. S2.2: The pressure and temperature of the tail gas before and after cooling are monitored in real time by the pressure transmitter and temperature transmitter instrument valve group in the triethylene glycol tail gas recovery control valve group. Then, the cooled gas-liquid two-phase triethylene glycol tail gas is passed through the gas-liquid two-phase flow meter in the triethylene glycol tail gas recovery control valve group to accurately measure the gas phase and liquid phase flow of the triethylene glycol tail gas. S2.3: Open the electric ball valve two in the vent main recovery gas control valve group to allow the VOCs gas in the vent main to enter the pretreatment system. At the same time, the VOCs gas in the vent main flows through the filter two in the vent main recovery gas control valve group and filters out the condensate oil and mechanical impurities contained in the VOCs gas. S2.4: The pressure and temperature of the VOCs gas entering the pretreatment system are monitored in real time by the pressure transmitter and temperature transmitter instrument valve group in the vent main recovery gas control valve group. The VOCs gas in the vent main after filtration and parameter monitoring flows through the Barrel flow meter in the vent main recovery gas control valve group to accurately measure the VOCs gas.

4. The process of claim 3, wherein the process is characterized by, The specific steps of the first-stage boost described in step II are as follows: S3.1: The pretreated triethylene glycol exhaust gas is introduced into the single-stage booster cylinder cavity of the triethylene glycol exhaust gas booster water-cooled hydraulic cylinder through a dedicated pipeline. At the same time, during the connection process, the pressure transmitter of the front-end pretreatment stage monitors the intake pressure in real time, starts the hydraulic system, delivers hydraulic oil to the hydraulic cylinder of the triethylene glycol exhaust gas booster water-cooled hydraulic cylinder, and drives the hydraulic cylinder piston to reciprocate. The piston mechanically compresses the triethylene glycol exhaust gas in the single-stage booster cylinder cavity. S3.2: During the compression process, the water cooling heat exchange system of the triethylene glycol tail gas booster water-cooled hydraulic cylinder is simultaneously activated. The circulating cooling water continuously absorbs the heat generated during the gas compression process through the heat exchange channel of the cylinder until the first stage of boosting is completed. S3.3: The VOCs gas from the pretreated venting manifold is introduced into the single-stage booster cylinder of the venting manifold recovery gas booster water-cooled hydraulic cylinder through a pipeline adapted for low flow rate and low velocity conditions. When connected, the opening of the inlet valve is adjusted in real time based on the real-time data of the Barrel flow meter to ensure that the gas enters the cavity evenly. S3.4: The hydraulic system supplies hydraulic oil to the hydraulic cylinder of the gas recovery booster water-cooled hydraulic cylinder in the vent manifold, and drives the piston of the hydraulic cylinder to reciprocate. This, in turn, drives the piston in the single-stage booster cylinder to perform reciprocating compression action synchronously. At the same time, during the compression process, the water cooling heat exchange system of the gas recovery booster water-cooled hydraulic cylinder in the vent manifold continues to operate. The circulating cooling water absorbs the heat generated by compression and controls the gas temperature in the single-stage booster cylinder until the first stage of boosting is completed.

5. The process of claim 4, wherein the process is characterized by, The specific steps for mixing the various gases after primary pressurization, as described in Step III, along with real-time safety monitoring and venting, and cooling and temperature control of the mixed gas, are as follows: S4.1: The triethylene glycol tail gas and VOCs gas that have completed the first stage of pressurization are connected to the same flow channel through a dedicated confluence pipeline for preliminary mixing of the two types of gases. The uniformly mixed gas is then introduced into the water-cooled heat exchanger of the interstage control valve group for the mixed gas. The mixed gas exchanges heat with the circulating cooling water, absorbing the residual heat of the mixed gas during the first stage of pressurization and the heat generated during the mixing process, so that the temperature of the mixed gas is reduced to the process range suitable for the second stage of pressurization. S4.2: The pressure transmitter continuously collects the current pressure value of the mixed gas and determines whether the pressure is within the initial pressure range allowed by the secondary boosting. If the pressure is lower than the preset threshold, it is fed back to the front-end primary boosting system and the parameters are adjusted. If the pressure is higher than the preset threshold, the subsequent safety relief mechanism is triggered. The temperature of the mixed gas after cooling is recorded in real time by the temperature transmitter to evaluate whether the water cooling effect meets the standard. If the temperature exceeds the preset range, the circulating water flow or temperature of the water cooling system is adjusted until the temperature of the mixed gas meets the requirements. S4.3: When the safety relief mechanism is triggered, the safety relief valve group of the interstage control valve group of the mixed gas automatically opens and safely relieves the pressure of the overpressure part of the mixed gas through a dedicated relief pipeline until the pressure of the mixed gas drops to within the preset safe range. Then, the safety relief valve group automatically closes and terminates the relief.

6. The process as claimed in claim 5, wherein, The specific steps for performing two-stage pressurization on the gas mixture in step IV, and for pre-treating the gas mixture after two-stage pressurization for external export, are as follows: S5.1: The mixed gas, which has been cooled between stages and meets the pressure and temperature standards, is introduced into the single-stage booster cylinder cavity of the two-stage booster water-cooled hydraulic cylinder through a dedicated pipeline. The pressure transmitter of the mixed gas interstage control valve group confirms that the mixed gas pressure is stable, and the hydraulic system is started to deliver hydraulic oil with stable pressure to the hydraulic cylinder of the two-stage booster water-cooled hydraulic cylinder. S5.2: Hydraulic oil drives the piston of the hydraulic cylinder to reciprocate, and simultaneously drives the piston in the single-stage booster cylinder to reciprocate in the same direction. The piston mechanically compresses the gas mixture in the cavity, gradually reducing the gas volume. During the compression process, the water cooling heat exchange system of the single-stage booster cylinder is activated simultaneously, and the circulating cooling water continuously absorbs the heat generated by compression through the cylinder heat exchange channel. S5.3: The pressure of the mixed gas after pressurization is monitored in real time by the pressure transmitter at the outlet of the two-stage pressurization water-cooled hydraulic cylinder. If the pressure does not reach the preset standard, the power output of the hydraulic system is adjusted. If the pressure exceeds the preset standard, the local safety relief valve is triggered for adjustment until the pressure stabilizes within the range of the gathering and transmission pipeline network. S5.4: The mixed gas after secondary pressurization is introduced into the water-cooled heat exchanger of the mixed gas output control valve group. The mixed gas is finally cooled by circulating cooling water. During the cooling process, the outlet temperature is monitored in real time by a temperature transmitter. If the temperature exceeds the preset standard, the circulating water flow rate of the water cooling system is adjusted until the temperature meets the transmission temperature requirements of the station's collection and transmission pipeline network. S5.5: Using the pressure transmitter and temperature transmitter instrument valve group of the mixed gas export control valve group, the pressure and temperature of the mixed gas after final cooling are collected in real time. If the pressure is detected to exceed the preset standard, the safety relief valve group is automatically opened to safely release the overpressure part of the mixed gas through a dedicated pipeline until the pressure drops to the standard range and then automatically closes. S5.6: Cooled and qualified mixed gas flows into the gas flow meter of the mixed gas export control valve group through the pipeline, and the export flow of the mixed gas is accurately measured. At the same time, the mixed gas flows through the check valve after measurement. After the check valve is checked and found to be correct, the electric ball valve of the mixed gas export control valve group is confirmed to be in the closed state. After all export parameters have reached the preset standards, the electric ball valve is opened to export.

7. The centralized VOCs gas zero-emission recovery process method for a station as described in claim 6, characterized in that, The specific steps for connecting the pretreated mixed gas to the station's gathering and transmission pipeline network, as described in step IV, are as follows: S6.1: After confirming that all parameters of the mixed gas export pretreatment and metering process meet the requirements, the electric ball valve three of the mixed gas export control valve group is opened remotely or on-site through the control system, and the valve opening is slowly adjusted. After the electric ball valve three is opened, the mixed gas is connected to the station's gathering and transmission network through a dedicated export pipeline, and enters the subsequent natural gas processing system together with the raw gas in the pipeline network. S6.2: After the mixed gas is stably connected to the gathering and transmission pipeline network, turn off the fuel supply to the flare lamp, extinguish the lamp, close the control valve of the flare main combustion system, ensure that the flare is not in a combustion state, and at the same time check that the connection valve between the vent flare and the vent main is closed.

8. A centralized VOCs gas zero-emission recovery device for a station, used to implement the centralized VOCs gas zero-emission recovery process method according to any one of claims 1-7, characterized in that, It includes a venting main venting control valve assembly (1), a triethylene glycol tail gas recovery control valve assembly (2), a triethylene glycol tail gas booster water-cooled hydraulic cylinder (3), a venting main recovery gas control valve assembly (4), a venting main recovery gas booster water-cooled hydraulic cylinder (5), a mixed gas interstage control valve assembly (6), a mixed gas two-stage booster water-cooled hydraulic cylinder (7), a mixed gas external transmission control valve assembly (8), a water cooling system (9), and a hydraulic system (10). The venting manifold discharge control valve group (1) includes a pressure transmitter (101), ball valve one (102), ball valve two (106), pressure regulating valve (104), electro-hydraulic quick-opening butterfly valve (105), rupture disc (103), and flame arrester (107). The triethylene glycol tail gas recovery control valve group (2) includes a filter (201), an electric ball valve (202), a water-cooled heat exchanger (204), a pressure transmitter and temperature transmitter instrument valve group (203), a pressure transmitter and temperature transmitter instrument valve group (205), and a gas-liquid two-phase flow meter (206). The triethylene glycol tail gas booster water-cooled hydraulic cylinder (3) includes a single-stage booster cylinder, a hydraulic cylinder and a water-cooled heat exchange system; The vent main recovery gas control valve group (4) includes filter two (301), electric ball valve two (302), pressure transmitter and temperature transmitter instrument valve group three (303) and bar flow meter (304). The venting manifold recovers gas pressurized water-cooled hydraulic cylinder (5) includes a single-stage pressurized cylinder, a hydraulic cylinder, and a water-cooled heat exchange system. The mixed gas stage control valve group (6) includes a water-cooled heat exchanger two (402), a safety relief valve group one (404), a pressure transmitter and temperature transmitter instrument valve group four (401), and a pressure transmitter and temperature transmitter instrument valve group five (403). The mixed gas two-stage booster water-cooled hydraulic cylinder (7) includes a single-stage booster cylinder, a hydraulic cylinder and a water-cooled heat exchange system; The mixed gas export control valve group (8) includes a pressure transmitter and temperature transmitter instrument valve group six (501), a safety relief valve group, a water-cooled heat exchanger three (503), a gas flow meter (504), a check valve (505), and an electric ball valve three (506).

9. A centralized VOCs gas zero-emission recovery device for a station according to claim 8, characterized in that, The venting main discharge control valve group (1) is installed on the venting main upstream of the venting flare, replacing the venting main of the same length as part of the venting main; the outlet of the triethylene glycol tail gas recovery control valve group (2) is connected to the triethylene glycol tail gas booster water-cooled hydraulic cylinder (3); the venting main recovery gas control valve group (4) is connected to the venting main recovery gas booster water-cooled hydraulic cylinder (5); after the triethylene glycol tail gas booster water-cooled hydraulic cylinder (3) and the venting main recovery gas booster water-cooled hydraulic cylinder (5) are mixed, they are connected to the mixed gas secondary booster water-cooled hydraulic cylinder (7) through the mixed gas interstage control valve group (6), and then connected to the station's collection and transmission pipeline network through the mixed gas external transmission control valve group (8); The pressure regulating valve (104), the electro-hydraulic quick-opening butterfly valve, and the rupture disc (103) together form a safety system with three-stage pressure relief capability. The pressure regulating valve (104) is the first-stage pressure relief safety system with the lowest pressure value, set at 0.2 MPa. The electro-hydraulic quick-opening butterfly valve (105) is the second-stage pressure relief safety system with a higher pressure value than the pressure regulating valve (104), set at 0.25 MPa. The rupture disc (103) is the third-stage pressure relief safety system with a higher pressure value than both the pressure regulating valve (104) and the electro-hydraulic quick-opening butterfly valve (105), set at 0.35 MPa.

Images