Flash gas recovery integrated device and recovery method

Abstract

The present invention provides an integrated flash gas recovery device and recovery method, including a skid, on which a gas-liquid separation system, a boosting system and a PLC control cabinet are provided. The gas outlet of the gas-liquid separation system is connected to the boosting system, and both the gas-liquid separation system and the boosting system are electrically connected to the PLC control cabinet. The present invention is a combined device that combines the functions of flash gas gas-liquid separation, compressor boosting, natural gas replenishment, flow metering, and remote venting. The flash gas is separated and boosted before being recovered and connected to the raw gas pipeline network, thereby solving the problem of flash gas carrying liquid and avoiding waste of resources. The PLC control cabinet monitors the values ​​of each sensor on the skid and controls each valve, realizing unmanned operation. At the same time, an RTU is set to monitor the gas-liquid separator and compressor pressure, temperature, liquid level monitoring, and other remote control, and remote emergency shutdown control of the compressor in an accident state, realizing remote monitoring and control.

Description

Technical Field

[0001] The present invention belongs to the technical field of flash vapor recovery, and in particular relates to an integrated flash vapor recovery device and a recovery method. Background Art

[0002] The dehydration and dehydrogenation processes at natural gas processing plants in the Sulige and Shenmu gas fields of the Changqing Gas Field all utilize a propane refrigeration low-temperature separation process, with propane refrigeration temperatures of -15°C (winter) and -5°C (summer). Heavy hydrocarbons condensed from the natural gas enter a flash separator for three-phase separation into gas, water, and oil. The separated unstabilized condensate enters a condensate stabilization unit to generate stabilized condensate. The separated flash gas and overhead gas from the condensate stabilization tower are fed into the fuel gas system for use in thermal oil boilers or fed into a low-pressure flare for combustion.

[0003] The following problems exist in on-site operation: (1) The content of heavy hydrocarbon components in the flash gas is high, and condensate is produced when it is used as fuel gas. There is a risk of flash explosion when the thermal oil furnace is ignited, which poses a safety hazard; (2) When connected to a low-pressure torch for combustion, the flash gas is not fully burned with liquid, and black smoke is produced, which is not conducive to environmental protection. Summary of the Invention

[0004] The purpose of the present invention is to provide an integrated flash gas recovery device to overcome the above-mentioned technical problems existing in the prior art.

[0005] Another object of the present invention is to provide a flash gas recovery method that solves the problem of flash gas carrying liquid and can be automatically and remotely controlled.

[0006] To this end, the technical solutions provided by the present invention are as follows:

[0007] A flash gas recovery integrated device includes a skid, on which a gas-liquid separation system, a pressurizing system and a PLC control cabinet are provided. An outlet of the gas-liquid separation system is connected to the pressurizing system, and both the gas-liquid separation system and the pressurizing system are connected to the PLC control cabinet for electrical signals.

[0008] The skid is also provided with an RTU, which is connected to a monitoring system for communication.

[0009] The gas-liquid separation system includes a gas-liquid separator and an air inlet line 1, wherein the air inlet 1 of the gas-liquid separator is connected to the flash gas inlet line through the air inlet line 1, and a liquid level sensor is installed on the gas-liquid separator;

[0010] The air inlet line 1 is provided with a flash gas inlet control valve and a pressure gauge 1, the gas-liquid separator is installed with a pressure gauge 2, the air inlet line 1 is connected to the vent line 1, the vent line 1 is connected to the vent system, the vent line 1 is provided with a valve, the air inlet line 1 is installed with a pressure transmitter and a temperature transmitter, the liquid level sensor, pressure transmitter 1 and temperature transmitter 1 are all electrically connected to the PLC control cabinet and / or RTU.

[0011] The boosting system includes a compressor, the second air inlet of the compressor is connected to the second air inlet pipeline, and the first air outlet of the gas-liquid separation system is connected to the second air inlet of the compressor through the second air inlet pipeline;

[0012] The second air outlet of the compressor is connected to the raw gas pipeline network of the processing plant through an exhaust pipeline. A second pressure transmitter, a third pressure gauge, a check valve, a flow meter and an electric valve are sequentially provided on the exhaust pipeline along the gas flow direction. The compressor, the second pressure transmitter, the flow meter and the electric valve are all electrically connected to the PLC control cabinet and / or RTU.

[0013] The air inlet line 1 is also connected to a supplementary air source line, and the connection point between the supplementary air source line and the air inlet line 1 is located between the installation point of the pressure transmitter 1 and the connection point between the vent line 1 and the air inlet line 1;

[0014] The supplementary gas source pipeline is provided with a pressure gauge four, a supplementary gas source pipeline ball valve, a self-operated regulating valve and an electric ball valve one in sequence along the gas flow direction. The self-operated regulating valve and the electric ball valve are both electrically connected to the PLC control cabinet and / or RTU.

[0015] The valves provided on the vent line 1 include a gate valve 1, a safety valve and a gate valve 2 which are sequentially provided along the gas flow direction;

[0016] The air inlet pipeline 1 is also connected to the vent pipeline 2, and the vent pipeline 2 is connected to the vent system. The vent pipeline 2 is provided with an electric ball valve 2 and a throttle stop valve in sequence along the gas flow direction. The electric ball valve 2 is electrically connected to the PLC control cabinet and / or RTU.

[0017] The exhaust pipeline is connected to the vent pipeline three, and the vent pipeline three is connected to the vent system. A ball valve is provided on the vent pipeline three, and the connection point between the vent pipeline three and the exhaust pipeline is located between the flow meter and the check valve.

[0018] An emergency drain port and a manual drain port are provided at the bottom of the gas-liquid separator. A drain ball valve is provided at the emergency drain port. The manual drain port is connected to a drain line. A drain ball valve is provided on the drain line. The drain line is connected to a condensate oil line.

[0019] The compressor sewage outlet of the boosting system is connected to a sewage pipeline, a liquid discharge gate valve is provided on the sewage pipeline, the sewage pipeline is connected to the condensate oil pipeline, a vent is provided on the exhaust pipeline of the compressor, the vent is connected to a vent pipeline four, and a vent gate valve is provided on the vent pipeline four.

[0020] The compressor includes a separator 1, a first-level cylinder, a first-level air-cooled cooler, a separator 2, a second-level cylinder, a second-level air-cooled cooler and a separator 3 which are connected in sequence. A temperature sensor 2 is installed on the pipeline between the second-level exhaust port of the second-level cylinder and the second-level air-cooled cooler. The separator 3 is connected to the air outlet 2 of the compressor through a pipeline. A pressure transmitter 3 is installed on the pipeline. The temperature sensor 2 and the pressure transmitter 3 are both electrically connected to the PLC control cabinet and / or RTU.

[0021] A flash gas recovery method employs an integrated flash gas recovery device. Flash gas is drawn from a flash gas inlet pipeline, enters a gas-liquid separator through a first gas inlet pipeline and a first gas inlet of the gas-liquid separator, and after heavy hydrocarbon droplets carried along are separated, the gas is discharged from a first gas outlet of the gas-liquid separator, enters a compressor of a boosting system through a second gas inlet pipeline for boosting and gas-liquid separation, and after being boosted to 1.8 MPa to 2.5 MPa by the compressor, the gas is discharged through a second gas outlet of the boosting system to a raw gas pipeline network of a processing plant for raw gas recovery. The heavy hydrocarbons separated by the gas-liquid separator and the boosting system are discharged to a condensate oil stabilization device.

[0022] When the pressure transmitter 1 on the air inlet line detects that the air inlet pressure is lower than the set lower limit, the supplementary air source line ball valve on the supplementary air source line is opened. The self-operated regulating valve opens when the set opening pressure is reached, and the PLC control cabinet sends a command to open the electric ball valve 1 to replenish natural gas. When the pressure transmitter 1 on the air inlet line detects that the air inlet pressure is higher than the set upper limit, the PLC control cabinet sends a command to close the electric ball valve 1.

[0023] When the flash gas temperature is higher than 135°C or the compressor outlet pressure is higher than 2.555 MPa after the compressor of the boosting system is boosted, the PLC control cabinet or RTU sends a command to stop the compressor.

[0024] The beneficial effects of the present invention are:

[0025] The integrated flash gas recovery device provided by the present invention performs gas-liquid separation and pressurization on the flash gas in the natural gas processing plant through a gas-liquid separation system and a pressurization system, thereby separating the heavy hydrocarbon components in the flash gas. The treated gas is connected to the raw gas pipeline network as raw gas, thereby protecting the environment, eliminating safety hazards, and increasing economic benefits.

[0026] The present invention is a combined device that combines the functions of flash gas gas-liquid separation, compressor boosting, natural gas supply, flow metering, and remote venting. The flash gas is separated and boosted before being recovered and connected to the raw gas pipeline network, thereby solving the problem of flash gas carrying liquid and avoiding waste of resources.

[0027] This invention utilizes a PLC control cabinet to monitor the values ​​of various sensors on the skid and control each valve, achieving unattended operation. Furthermore, an RTU monitors the pressure, temperature, and liquid level of the gas-liquid separator and compressor on the skid, providing over-limit alarms, remote control of electric ball valves, and remote emergency shutdown of the compressor in the event of an emergency. All production data is transmitted to the natural gas processing plant's monitoring system, enabling remote monitoring and control.

[0028] In order to make the above contents of the present invention more clearly understood, preferred embodiments are given below with reference to the accompanying drawings for detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the connection composition of the present invention;

[0030] Figure 2 It is a structural schematic diagram of the present invention.

[0031] In the picture:

[0032] Description of reference numerals:

[0033] 1. Air inlet 1; 2. Air outlet 1; 3. Emergency drain outlet 3; 4. Manual drain outlet 4; 5. Air inlet 2; 6. Air outlet 2; 7. Vent; 8. Drain outlet; 9. Condensate oil pipeline; 101. Pressure gauge 1; 102. Flash gas inlet control valve; 103. Pressure gauge 4; 104. Ball valve for supplementary air supply pipeline; 105. Gate valve 1; 106. Safety valve; 107. Gate valve 2; 108, throttle stop valve; 109, pressure gauge 2; 110, blowdown ball valve; 111, blowdown ball valve; 112, air inlet line 1; 113, vent line 1; 114, supplementary air source line; 115, vent line 2; 116, drain line; 200, compressor; 201, air inlet line 2; 202, exhaust line; 203, check valve; 204, pressure gauge 3; 205 , ball valve; 206, vent gate valve; 207, drain gate valve; 208, separator one; 209, separator two; 210, separator three; 211, first-stage cylinder; 212, second-stage cylinder; 213, first-stage air-cooled cooler; 214, second-stage air-cooled cooler; 215, crankcase; 216, variable frequency main motor; 217, vent pipeline three; 218, drain pipeline; 219, vent pipeline four; 220, first-stage exhaust port; 221, second-stage exhaust port; 301, self-operated regulating valve; 302, electric ball valve one; 303, pressure transmitter one; 304, temperature sensor one; 305, electric ball valve two; 306, liquid level sensor; 307, electric valve; 308, flow meter; 309, pressure transmitter two; 310, temperature sensor two; 311, pressure transmitter three. DETAILED DESCRIPTION

[0034] The following describes the embodiments of the present invention through specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0035] It should be noted that, in the present invention, the top, bottom, left and right in the figure are deemed to be the top, bottom, left and right of the integrated flash vapor recovery device described in this specification.

[0036] Exemplary embodiments of the present invention will now be described with reference to the accompanying drawings. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided so as to provide a thorough and complete disclosure of the present invention and fully convey the scope of the present invention to those skilled in the art. The terminology used in the exemplary embodiments shown in the accompanying drawings is not intended to limit the present invention. In the accompanying drawings, identical elements are denoted by the same reference numerals.

[0037] Unless otherwise specified, the terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art. Furthermore, it is understood that terms defined in commonly used dictionaries should be understood to have meanings consistent with the context of their relevant fields and should not be interpreted as idealized or overly formal.

[0038] Example 1:

[0039] This embodiment provides an integrated flash gas recovery device, including a skid, on which a gas-liquid separation system, a boosting system and a PLC control cabinet are provided. The gas outlet 2 of the gas-liquid separation system is connected to the boosting system, and the gas-liquid separation system and the boosting system are both electrically connected to the PLC control cabinet.

[0040] Specifically, the working process provided in this embodiment is as follows:

[0041] like Figure 1 As shown, the flash gas enters the gas-liquid separation system, and after the heavy hydrocarbon droplets carried are separated, it is discharged from the gas-liquid separation system, and then enters the boosting system. After boosting, it is recovered and connected to the raw gas pipeline network, and the separated heavy hydrocarbon components are discharged into the condensate oil stabilization device.

[0042] The present invention solves the problem of liquid entrainment in flash gas, avoids waste of resources, eliminates potential safety hazards, and protects the environment at the same time.

[0043] Example 2:

[0044] On the basis of Example 1, this embodiment provides an integrated flash gas recovery device, wherein the skid is further provided with an RTU, and the RTU is communicatively connected to a monitoring system.

[0045] The RTU monitors various operating parameters on the skid and transmits all production data to the natural gas processing plant monitoring system to achieve remote monitoring and control.

[0046] Example 3:

[0047] Based on Example 2, this embodiment provides an integrated flash gas recovery device, wherein the gas-liquid separation system includes a gas-liquid separator and an air inlet line 112. The air inlet 1 of the gas-liquid separator is connected to the flash gas inlet line via the air inlet line 112. A liquid level sensor 306 is installed on the gas-liquid separator.

[0048] The air inlet line 112 is provided with a flash gas inlet control valve 102 and a pressure gauge 101, the gas-liquid separator is installed with a pressure gauge 109, the air inlet line 112 is connected to a vent line 113, the vent line 113 is connected to the vent system, the vent line 113 is provided with a valve, the air inlet line 112 is installed with a pressure transmitter and a temperature transmitter, the liquid level sensor 306, the pressure transmitter 303 and the temperature transmitter are all electrically connected to the PLC control cabinet and / or RTU.

[0049] like Figure 2 As shown, the PLC control cabinet monitors the value of liquid level sensor 306, and the RTU remotely monitors the liquid level of the gas-liquid separator. The inlet pressure of inlet line 112 is measured by pressure transmitter 303, and the inlet temperature of inlet line 112 is measured by temperature sensor 304. Vent line 113 is used for constant pressure venting and emergency venting.

[0050] Working process: Flash gas comes from the flash gas inlet pipeline, enters the gas-liquid separator through the air inlet pipeline 112 and the air inlet 1 of the gas-liquid separator, and after separating the heavy hydrocarbon droplets carried, the gas is discharged from the air outlet 2 of the gas-liquid separator, and enters the compressor 200 of the boosting system through the air inlet pipeline 201 for boosting and gas-liquid separation. After boosting by the compressor 200, the gas is discharged to the raw gas pipeline network of the processing plant through the boosting system for raw gas recovery. The heavy hydrocarbons separated by the gas-liquid separator and the boosting system are discharged to the condensate oil stabilization device.

[0051] Example 4:

[0052] Based on Example 2, this embodiment provides an integrated flash gas recovery device, wherein the boosting system includes a compressor 200, an air inlet 25 of the compressor 200 is connected to an air inlet line 201, and an air outlet 2 of the gas-liquid separation system is connected to the air inlet 25 of the compressor 200 through the air inlet line 201;

[0053] The air outlet 26 of the compressor 200 is connected to the raw gas pipeline network of the processing plant through an exhaust pipeline 202. The exhaust pipeline 202 is provided with a second pressure transmitter 309, a third pressure gauge 204, a check valve 203, a flow meter 308 and an electric valve 307 in the direction of gas flow. The compressor 200, the second pressure transmitter 309, the flow meter 308 and the electric valve 307 are all electrically connected to the PLC control cabinet and / or RTU. Figure 2 shown.

[0054] Pressure gauge 3 204 displays the pressure of exhaust line 202 locally. Pressure transmitter 2 309 transmits the pressure reading to the PLC control cabinet and RTU. Flow meter 308 transmits the flow rate to the RTU, enabling remote monitoring. When the pressure of exhaust line 202 reaches the required pressure of the processing plant's raw gas network, the PLC control cabinet sends a command to open electric valve 307, discharging the treated flash gas into the raw gas network.

[0055] Example 5:

[0056] Based on Example 3, this embodiment provides an integrated flash gas recovery device, wherein the air inlet line 112 is further connected to a supplementary air source line 114, and the connection point between the supplementary air source line 114 and the air inlet line 112 is located between the installation point of the pressure transmitter 303 and the connection point between the vent line 113 and the air inlet line 112;

[0057] The supplementary gas source pipeline 114 is provided with a pressure gauge 103, a supplementary gas source pipeline ball valve 104, a self-operated regulating valve 301 and an electric ball valve 302 in sequence along the gas flow direction. The self-operated regulating valve 301 and the electric ball valve 205 are both electrically connected to the PLC control cabinet and / or RTU.

[0058] like Figure 2 As shown, the pressure transmitter 303 measures the intake pressure of the intake line 112. When the intake pressure on the intake line 112 is lower than the set lower limit, the supplementary gas source pipeline ball valve 104 on the supplementary gas source pipeline 114 is opened, and the self-operated regulating valve 301 opens when the set opening pressure is reached. The PLC control cabinet sends a command to open the electric ball valve 302 to replenish natural gas. When the intake pressure on the intake line 112 is higher than the set upper limit, the PLC control cabinet sends a command to close the electric ball valve 302.

[0059] In this embodiment, the self-operated regulating valve 301 is set to open at 0.2 MPa. When the air inlet pressure of the gas-liquid separator is lower than 0.2 MPa, the PLC control cabinet opens the electric ball valve 302 behind the self-operated regulating valve 301 to replenish fuel gas; when the air inlet pressure of the gas-liquid separator is higher than 0.4 MPa, the PLC control cabinet closes the electric ball valve 302 behind the self-operated regulating valve 301.

[0060] Example 6:

[0061] Based on Example 3, this embodiment provides an integrated flash gas recovery device, wherein the valves provided on the vent line 113 include a gate valve 105, a safety valve 106, and a gate valve 2 107, which are sequentially provided along the gas flow direction;

[0062] The inlet line 112 is also connected to the vent line 2 115, which is connected to the vent system. The vent line 2 115 is provided with an electric ball valve 2 305 and a throttle stop valve 108 in sequence along the gas flow direction. The electric ball valve 2 305 is electrically connected to the PLC control cabinet and / or RTU. Figure 2 shown.

[0063] When the equipment and pipelines are under maintenance, or the air pressure on the air inlet line 112 is too high, the safety valve 106 automatically opens, and the gate valve 105 and the gate valve 2 107 are opened to vent through the vent line 113.

[0064] When the valve on the gas vent line 113 fails and cannot be vented, the PLC control cabinet monitors the pressure value of the pressure transmitter 303 in real time. When the pressure upper limit is reached, the PLC control cabinet sends a command to open the electric ball valve 305 and vent through the vent line 115.

[0065] Example 7:

[0066] Based on Example 4, this example provides an integrated flash gas recovery device, wherein the exhaust line 202 is connected to the vent line three 217, and the vent line three 217 is connected to the vent system. A ball valve 205 is provided on the vent line three 217, and the connection point between the vent line three 217 and the exhaust line 202 is located between the flow meter 308 and the check valve 203.

[0067] When the pressure gauge 3 204 shows that the pressure on the exhaust line 202 exceeds the upper pressure limit, the ball valve 205 is opened to vent through the vent line 3 217. Figure 2 shown.

[0068] Example 8:

[0069] Based on Example 3, this embodiment provides an integrated flash gas recovery device. The bottom of the gas-liquid separator is provided with an emergency drain port 3 and a manual cleaning drain port 4. The emergency drain port 3 is provided with a drain ball valve 110. The manual cleaning drain port 4 is connected to a drain line 116. The drain line 116 is provided with a clean ball valve 111. The drain line 116 is connected to the condensate oil pipeline 9.

[0070] The sewage outlet 8 of the compressor 200 of the boosting system is connected to a sewage pipeline 218, on which a liquid discharge gate valve 207 is provided. The sewage pipeline 218 is connected to the condensate oil pipeline 9. The exhaust pipeline 202 of the compressor 200 is provided with a vent port 7, which is connected to a vent pipeline four 219, on which a vent gate valve 206 is provided.

[0071] like Figure 2 As shown, the heavy hydrocarbon components separated by the gas-liquid separator and the boosting system enter the condensate pipeline 9 through the liquid discharge line 116 and the sewage discharge line 218, and finally enter the condensate stabilization device. If the sewage cleaning ball valve 111 on the liquid discharge line 116 fails, the liquid can be discharged through the emergency sewage outlet 3.

[0072] Before the boost compression is completed, when the gas pressure exceeds the safety value, it is vented through the vent pipeline 219.

[0073] Example 9:

[0074] Based on Example 4, this embodiment provides an integrated flash gas recovery device, wherein the compressor 200 includes a separator 1 208, a first-level cylinder 211, a first-level air-cooled cooler 213, a separator 209, a second-level cylinder 212, a second-level air-cooled cooler 214 and a separator 3 210 connected in sequence, and a temperature sensor 2 310 is installed on the pipeline between the second-level exhaust port 221 of the second-level cylinder 212 and the second-level air-cooled cooler 214. The separator 3 210 is connected to the air outlet 2 6 of the compressor 200 through a pipeline, and a pressure transmitter 3 311 is installed on the pipeline. The temperature sensor 2 310 and the pressure transmitter 3 311 are both electrically connected to the PLC control cabinet and / or RTU.

[0075] like Figure 2 As shown, the primary cylinder 211 and the secondary cylinder 212 are both connected to the crankcase 215 , and the crankcase 215 is connected to the variable frequency main motor 216 .

[0076] Usage process: The gas discharged from the gas outlet 2 of the gas-liquid separator enters the separator 1 208 of the compressor 200 through the air inlet pipeline 201, and enters the first-level cylinder 211 after separation. After compression, it is discharged from the first-level exhaust port 220 of the first-level cylinder 211 and enters the first-level air-cooled cooler 213 for cooling. After cooling, it enters the separator 2 209 for gas-liquid separation, and then enters the second-level cylinder 212 for compression. After the second-level compression, it is discharged through the second-level exhaust port 221 and enters the second-level air-cooled cooler 214 for cooling. After cooling, it enters the separator 3 210 for gas-liquid separation, and finally discharged from the boosting system through the gas outlet 2 6.

[0077] The heavy hydrocarbon components separated by separator 1 208, separator 2 209 and separator 3 210 all enter the condensate pipeline 9 through their respective sewage pipelines 218 and finally enter the condensate stabilization device.

[0078] Among them, the pipeline between the first-level exhaust port 220 of the first-level cylinder 211 and the first-level air-cooled cooler 213 is connected to the vent pipeline four 219, and the vent pipeline four 219 is provided with a safety valve and a vent gate valve 206. When the gas pressure exceeds the safety value, the safety valve automatically opens and the gas is discharged through the vent pipeline four 219.

[0079] Example 10:

[0080] This embodiment provides a flash gas recovery method, which uses an integrated flash gas recovery device. Flash gas is drawn from a flash gas inlet pipeline, enters a gas-liquid separator through an inlet pipeline 112 and an inlet 1 of the gas-liquid separator, and after heavy hydrocarbon droplets carried by the gas are separated, the gas is discharged from an outlet 2 of the gas-liquid separator, enters a compressor 200 of a boosting system through an inlet pipeline 201 for boosting and gas-liquid separation, and after being boosted to 1.8 MPa to 2.5 MPa by the compressor 200, the gas is discharged through an outlet 26 of the boosting system to a raw gas pipeline network of a processing plant for raw gas recovery. The heavy hydrocarbons separated by the gas-liquid separator and the boosting system are discharged to a condensate stabilization device.

[0081] When the pressure transmitter 303 on the air inlet line 112 detects that the air inlet pressure is less than the set lower limit, the supplementary air source line ball valve 104 on the supplementary air source line 114 is opened. The self-operated regulating valve 301 opens when the set opening pressure is reached. The PLC control cabinet sends a command to open the electric ball valve 302 to replenish natural gas. When the pressure transmitter 303 on the air inlet line 112 detects that the air inlet pressure is greater than the set upper limit, the PLC control cabinet sends a command to close the electric ball valve 302.

[0082] When the flash gas temperature of the compressor 200 of the boosting system is higher than 135° C. after boosting, or the outlet pressure of the compressor 200 is higher than 2.555 MPa, the PLC control cabinet or RTU sends a command to stop the compressor 200.

[0083] In this embodiment, the gas-liquid separator is a vertical separator operating at a pressure of 0.2-0.4 MPa. Flash gas enters the gas-liquid separator, where it is separated from any heavy hydrocarbon droplets carried by it. The gas is then discharged from the top of the gas-liquid separator and fed into compressor 200. A separate natural gas line is connected to flash gas inlet pipeline 112 as a supplemental gas source. This supplemental natural gas line is equipped with an electric ball valve 205 and a self-operated regulating valve 301. The self-operated regulating valve 301 is set to open at 0.2 MPa. When the gas-liquid separator inlet pressure falls below 0.2 MPa, the electric ball valve 205 behind the self-operated regulating valve 301 opens to allow fuel gas to be added. When the gas-liquid separator inlet pressure exceeds 0.4 MPa, the electric ball valve 205 behind the self-operated regulating valve 301 closes. Inlet pipeline 112 is equipped with vent line 113 (constant pressure vent) and vent line 215 (emergency vent).

[0084] The gas-liquid separator is provided with a pressure on-site display pressure gauge 109 for displaying the pressure inside the separator; a manual cleaning drain outlet 4 is provided for regular cleaning, and an emergency drain outlet 3 is provided for emergency liquid discharge.

[0085] Both the second inlet pipeline 201 and the exhaust pipeline 202 are metal hoses to reduce pipeline vibration. Flash gas enters compressor 200, where it is pressurized to 1.8-2.5 MPa before being discharged and recycled as feed gas for the processing plant. If the flash gas temperature after secondary compression exceeds 135°C, or if the outlet pressure of compressor 200 exceeds 2.555 MPa, compressor 200 is remotely shut down. Compressor 200 is equipped with a vent 7 and a drain 8.

[0086] The design pressure of compressor 200 exhaust line 202 is 4.0 MPa. The design pressure of the flash gas supply line, make-up gas source line 114, compressor 200 inlet line 2, drain line 116, and vent line 4 219 is 1.6 MPa. The pressure system level can also be set according to the actual operating pressure of different stations.

[0087] Those skilled in the art will appreciate that the above-mentioned embodiments are specific examples for implementing the present invention, and that in actual applications, various changes may be made thereto in form and detail without departing from the spirit and scope of the present invention.

Claims

1. A flash vapor recovery method using an integrated flash vapor recovery device, characterized in that: The flash gas recovery integrated device includes a skid, on which a gas-liquid separation system, a pressurizing system and a PLC control cabinet are arranged. The gas outlet 1 (2) of the gas-liquid separation system is connected to the pressurizing system, and both the gas-liquid separation system and the pressurizing system are connected to the PLC control cabinet for electrical signals; The gas-liquid separation system includes a gas-liquid separator and an air inlet line 1 (112), wherein the air inlet line 1 (112) is further connected to a supplementary gas source line (114), and a connection point between the supplementary gas source line (114) and the air inlet line 1 (112) is located between a pressure transmitter 1 (303) installation point and a connection point between the vent line 1 (113) and the air inlet line 1 (112); The supplementary gas source pipeline (114) is provided with a pressure gauge (103), a supplementary gas source pipeline ball valve (104), a self-operated regulating valve (301) and an electric ball valve (302) in sequence along the gas flow direction. The self-operated regulating valve (301) and the electric ball valve (205) are both electrically connected to the PLC control cabinet and / or RTU. An emergency drain port (3) and a manual drain port (4) are provided at the bottom of the gas-liquid separator. A drain ball valve (110) is provided at the emergency drain port (3). The manual drain port (4) is connected to a drain line (116). A drain ball valve (111) is provided on the drain line (116). The drain line (116) is connected to a condensate oil line (9). The blowdown port (8) of the compressor (200) of the boosting system is connected to a blowdown pipeline (218), a liquid discharge gate valve (207) is provided on the blowdown pipeline (218), and the blowdown pipeline (218) is connected to the condensate oil pipeline (9). The exhaust pipeline (202) of the compressor (200) is provided with a vent port (7), and the vent port (7) is connected to a vent pipeline four (219), and a vent gate valve (206) is provided on the vent pipeline four (219); The gas inlet port 1 (1) of the gas-liquid separator is connected to the flash gas inlet pipeline 1 (112), and a liquid level sensor (306) is installed on the gas-liquid separator; The air inlet line 1 (112) is provided with a flash gas inlet control valve (102) and a pressure gauge 1 (101), the gas-liquid separator is provided with a pressure gauge 2 (109), the air inlet line 1 (112) is connected to a vent line 1 (113), the vent line 1 (113) is connected to the vent system, the vent line 1 (113) is provided with a valve, the air inlet line 1 (112) is provided with a pressure transmitter and a temperature transmitter, the liquid level sensor (306), the pressure transmitter 1 (303) and the temperature transmitter 1 are all electrically connected to the PLC control cabinet and / or RTU; The boosting system comprises a compressor (200), the second air inlet (5) of the compressor (200) is connected to the second air inlet pipeline (201), and the first air outlet (2) of the gas-liquid separation system is connected to the second air inlet (5) of the compressor (200) via the second air inlet pipeline (201); The second gas outlet (6) of the compressor (200) is connected to the raw gas pipeline network of the processing plant through an exhaust pipeline (202). The exhaust pipeline (202) is provided with a second pressure transmitter (309), a third pressure gauge (204), a check valve (203), a flow meter (308) and an electric valve (307) in sequence along the gas flow direction. The compressor (200), the second pressure transmitter (309), the flow meter (308) and the electric valve (307) are all electrically connected to the PLC control cabinet and / or the RTU. Flash gas comes from the flash gas inlet pipeline, enters the gas-liquid separator through the gas inlet pipeline 1 (112) and the gas inlet 1 (1) of the gas-liquid separator, and after the heavy hydrocarbon droplets carried are separated, the gas is discharged from the gas outlet 1 (2) of the gas-liquid separator, enters the compressor (200) of the boosting system through the gas inlet pipeline 2 (201) for boosting and gas-liquid separation, and after being boosted to 1.8MPa~2.5MPa by the compressor (200), the gas is discharged through the gas outlet 2 (6) of the boosting system to the raw gas pipeline network of the processing plant for raw gas recovery, and the heavy hydrocarbons separated by the gas-liquid separator and the boosting system are discharged to the condensate oil stabilization device; When the pressure transmitter 1 (303) on the air inlet line 1 (112) detects that the air inlet pressure is less than the set lower limit, the supplementary air source line ball valve (104) on the supplementary air source line (114) is opened, and the self-operated regulating valve (301) opens when the set opening pressure is reached, and the PLC control cabinet sends a command to open the electric ball valve 1 (302) to replenish natural gas; When the pressure transmitter 1 (303) on the air inlet line 1 (112) detects that the air inlet pressure is greater than the set upper limit, the PLC control cabinet sends a command to close the electric ball valve 1 (302); When the flash gas temperature is higher than 135° C. after the compressor (200) of the boosting system boosts pressure, or the outlet pressure of the compressor (200) is higher than 2.555 MPa, the PLC control cabinet or the RTU sends a command to stop the compressor (200).

2. A flash gas recovery method according to claim 1, characterized in that: The skid is also provided with an RTU, which is connected to a monitoring system for communication.

3. A flash gas recovery method according to claim 1, characterized in that: The valves provided on the vent line 1 (113) include a gate valve 1 (105), a safety valve (106) and a gate valve 2 (107) which are sequentially provided along the gas flow direction; The first air inlet pipeline (112) is also connected to a second vent pipeline (115), and the second vent pipeline (115) is connected to the vent system. The second vent pipeline (115) is provided with an electric ball valve (305) and a throttle stop valve (108) in sequence along the gas flow direction. The second electric ball valve (305) is electrically connected to the PLC control cabinet and / or RTU.

4. A flash gas recovery method according to claim 1, characterized in that: The exhaust pipeline (202) is connected to a vent pipeline three (217), and the vent pipeline three (217) is connected to the vent system. A ball valve (205) is provided on the vent pipeline three (217). The connection point between the vent pipeline three (217) and the exhaust pipeline (202) is located between the flow meter (308) and the check valve (203).

5. A flash gas recovery method according to claim 1, characterized in that: The compressor (200) includes a separator 1 (208), a first-stage cylinder (211), a first-stage air-cooled cooler (213), a separator 2 (209), a second-stage cylinder (212), a second-stage air-cooled cooler (214) and a separator 3 (210) which are connected in sequence. A temperature sensor 2 (310) is installed on the pipeline between the second-stage exhaust port (221) of the second-stage cylinder (212) and the second-stage air-cooled cooler (214). The separator 3 (210) is connected to the second air outlet (6) of the compressor (200) through a pipeline. A pressure transmitter 3 (311) is installed on the pipeline. The temperature sensor 2 (310) and the pressure transmitter 3 (311) are both electrically connected to the PLC control cabinet and / or RTU.

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