A skid-mounted oilfield volatile gas recovery unit

Abstract

The utility model relates to oil and gas gathering and transferring equipment field, concretely is a kind of skid-mounted oilfield volatile gas recovery device, including sequentially connected first-stage flash evaporation buffer tank, compressor, air cooler and second-stage separation buffer tank, first-stage flash evaporation buffer tank is communicated with the storage tank of volatile gas by gas phase pipe network, and the gas phase outlet of second-stage separation buffer tank is connected with gas collection pipe network.The volatile gas of the storage tank in the tank area of the utility model station is entered first-stage flash evaporation buffer tank through gas phase pipe network, after being analyzed qualified by oxygen content monitor, preliminary flash evaporation separation liquid phase and gas phase in tank, liquid phase is entered station gathering and transferring system unit by blowdown pump, and the safety and airtightness of system are guaranteed.Gas phase enters compressor and is pressurized, and the gas after pressurization is cooled by air cooler, and after cooling, it enters second-stage separation buffer tank and is buffered, and the gas phase after buffering enters gas collection pipe network, and liquid phase enters station gathering and transferring system export unit, to complete the effect of forming gas, liquid automatic pressurization and conveying.

Description

Technical Field

[0001] This utility model relates to the field of oil and gas gathering and transportation equipment, specifically a skid-mounted oilfield volatile gas recovery device. Background Technology

[0002] During oil extraction, water-bearing oil extracted from wellheads is mainly processed at gathering and transportation stations. Many stations dehydrate and store the oil through settling tanks and purification tanks, which presents the following problems: (1) The crude oil in the storage tanks is not yet stable and contains a large amount of light hydrocarbon components. Because the existing storage tanks are equipped with breather valves, oil gauging ports, etc., which are connected to the atmosphere, they are not sealed. The volatile gas contains a large amount of air and oxygen components, which poses a high risk. (2) The stored crude oil is affected by factors such as medium composition, temperature, and air pressure. A large amount of hydrocarbon vapor in the gas phase space above the storage tank is emitted through the tank's breather (large and small breathers), oil gauging ports, etc., resulting in a large amount of volatile organic compounds, which wastes resources and pollutes the environment.

[0003] CN201437457U discloses an online automatic recovery device for volatile gas from an oil tank, comprising a compressor, an air cooler, a two-stage separator, a pressure transmitter, a pressure controller, a temperature controller, a variable frequency speed control motor, an automatic control system (CCS), and a data communication unit. The oil tank is connected to the inlet of the first-stage separator via a pipeline. A pressure transmitter is installed at the inlet of the first-stage separator and connected to the CCS. The outlet of the first-stage separator and the inlet of the second-stage separator are connected sequentially via pipelines to the first-stage and second-stage compression cylinders of the compressor. The compressor outlet is connected to an external gas pipeline. The first-stage and second-stage compression cylinders are connected to an air cooler. An interstage separator is installed between the compressor stages. The compressor is connected to the automatic control system (CCS). The compressor motor is a variable frequency speed control motor, and a temperature controller is installed on the compressor's exhaust line. A make-up gas line is installed between the oil tank and the first-stage separator. A make-up gas solenoid valve and a make-up gas pressure regulating valve are installed on the make-up gas line, and the make-up gas solenoid valve is connected to the automatic control system (CCS). Corresponding process valves are installed on the connecting pipelines of each component. The data communication unit is installed on the automatic control system (CCS). Continuous and uninterrupted gas recovery is achieved using the automatic control system and the make-up gas line, reducing environmental pollution and energy loss.

[0004] The aforementioned scheme employs a two-stage compression, interstage cooling and separation system, a variable frequency speed control system, and a more complex automatic control system. If the external gas source itself has insufficient pressure or is interrupted, its gas replenishment safety mechanism will fail, posing a risk of tank collapse. Furthermore, it neglects oxygen content analysis, and for systems collecting volatile gases from multiple storage tanks, there is always a risk of air intake due to tank seal failure. During the compression process of high-concentration oxygen and hydrocarbon gases, the lack of online oxygen content monitoring and interlocking shutdown functions poses a safety risk. Utility Model Content

[0005] To address the problems in the existing technology, this utility model provides a skid-mounted oilfield volatile gas recovery device.

[0006] This utility model is achieved through the following technical solution: A skid-mounted oilfield volatile gas recovery device includes a primary flash buffer tank, a compressor, an air cooler, and a secondary separation buffer tank connected in sequence. The primary flash buffer tank is connected to a volatile gas storage tank through a gas inlet manifold of a gas phase pipeline network, and the gas phase outlet of the secondary separation buffer tank is connected to a gas collection pipeline network.

[0007] Preferably, an aerobic content detector is connected to the primary flash buffer tank.

[0008] Preferably, the primary flash buffer tank is equipped with a gas phase outlet and a liquid phase outlet. The liquid phase outlet is connected to the collection and transportation system via a sewage pump, and the gas phase outlet is connected to the compressor inlet.

[0009] Preferably, the gas phase pressure at the compressor outlet is above 0.2 MPa.

[0010] Preferably, the secondary separation buffer tank is connected to an external gas source via a gas supply line, which is connected to the incoming gas manifold.

[0011] Preferably, the gas inlet manifold and the secondary separation buffer tank are controlled by pressure interlock.

[0012] Preferably, the gas supply line is connected to the secondary separation buffer tank via two pressure regulating valves, and a control valve is installed on the gas supply manifold, with the pressure regulating valve and the control valve interlocked.

[0013] Preferably, when the pressure of the incoming gas manifold is less than or equal to 200 Pa, the pressure regulating valve is opened to supply gas through the gas supply line, and the gas from the secondary buffer tank enters the incoming gas manifold.

[0014] Preferably, the condensate outlet of the secondary separation buffer tank is connected to the oil and gas system.

[0015] Preferably, it also includes a PLC control cabinet, which is used to collect pressure and liquid level data of each device and upload the data to the control room.

[0016] Compared with the prior art, the present invention has the following beneficial effects: This utility model discloses a skid-mounted oilfield volatile gas recovery device that uses a gas collection pipeline to achieve closed-loop recovery of tank gas, avoiding the emission of volatile organic compounds, meeting regulatory requirements, and realizing the recovery and utilization of volatile gas. Volatile gas from storage tanks in the station's tank area enters a primary flash buffer tank via a gas phase pipeline network. After passing oxygen content analysis, the gas undergoes initial flash separation into liquid and gas phases within the tank. The liquid phase is pumped into the station's gathering and transportation system unit, ensuring system safety and airtightness. The gas phase enters a compressor for pressurization, and the pressurized gas is cooled by an air cooler. After cooling, it enters a secondary separation buffer tank for buffering. The buffered gas phase then enters the gas collection pipeline network, while the liquid phase enters the station's external transportation unit, thus achieving the effect of automatic pressurized gas and liquid transport.

[0017] Furthermore, a two-stage air replenishment process is implemented to address the issue of insufficient air intake from the storage tank. Pressure control improves recovery efficiency, making the system more reliable and safer. Specifically, when the compressor stops, the pressure of the secondary separation buffer tank and the incoming air manifold is interlocked. The air replenishment pipeline is controlled by a PY pressure-electric conversion valve to regulate the pressure. When the pressure is increased to 200Pa, the PY pressure-electric conversion valve on the gas supply line opens to supply gas. Gas from the tank enters the gas manifold, achieving a gas phase balance system.

[0018] Furthermore, the PLC control cabinet system automatically collects real-time pressure and liquid level data, and uploads the data to the station where the device is located. Through remote monitoring, regular inspections, and emergency response, it can alleviate labor pressure. Attached Figure Description

[0019] Figure 1 This is a structural diagram of a skid-mounted oilfield volatile gas recovery device according to this utility model; Figure 2 This is a schematic diagram of the process of a skid-mounted oilfield volatile gas recovery device according to this utility model. In the diagram, 1. Primary flash buffer tank; 2. Compressor; 3. Air cooler; 4. Secondary separation buffer tank; 5. Drain pump; 6. PLC control cabinet; 7. Gas collection network; 8. Gas phase network; 9. Condensate outlet; 10. Oxygen content detector; 11. Flame arrester; 12. Sewage pump. Detailed Implementation

[0020] The present invention will be further described in detail below with reference to specific embodiments. The description is for explanation and not limitation of the present invention.

[0021] This utility model discloses a skid-mounted oilfield volatile gas recovery device, with reference to... Figure 1The system comprises a primary flash buffer tank 1, a compressor 2, an air cooler 3, and a secondary separation buffer tank 4, connected in sequence. The primary flash buffer tank 1 is connected to a volatile gas storage tank via a vapor phase pipeline network 8. The vapor phase outlet of the secondary separation buffer tank 4 is connected to a gas collection pipeline network 7, and the condensate outlet 9 of the secondary separation buffer tank 4 is connected to an oil and gas system. The drain outlet of the primary flash buffer tank 1 is connected to the drain outlet via a sludge pump.

[0022] In one embodiment, an oxygen content detector 10 is connected to the primary flash buffer tank 1 to monitor the oxygen concentration in the gas phase space in real time, thereby improving equipment safety.

[0023] In one embodiment, the primary flash buffer tank 1 is provided with a gas phase outlet and a liquid phase outlet. The liquid phase outlet is connected to the collection and transportation system through a sewage pump 12, and the gas phase outlet is connected to the inlet of the compressor 2.

[0024] A HY electric valve is connected between the primary flash buffer tank 1 and the gas phase pipeline network 8. The HY electric valve is a valve driven by a motor. The rotation of the motor drives the valve stem / valve core to move, thereby realizing "valve opening, closing or opening degree adjustment".

[0025] A LIT level gauge is installed on the side of the primary flash buffer tank 1. The LIT level gauge is used to measure the liquid level in the primary flash buffer tank 1. The LIT level gauge is connected to the LISA level display interlock alarm, which is an intelligent instrument that integrates "level display, over-limit alarm and interlock control". Its core function is to ensure the safety of the container liquid level.

[0026] A TIT temperature transmitter is installed on the pipe connecting the gas phase outlet to compressor 2. This device converts the "temperature signal" into a standard electrical signal and transmits it to the control room over a long distance.

[0027] An LY liquid level gas-electric conversion valve is installed on the liquid outlet pipeline to convert the measured liquid level signal on site into an electrical signal, thus providing liquid level control function.

[0028] The LY liquid level gas-electric conversion valve is operated via the HS manual switch, and its status is displayed by the ZI display switch status device.

[0029] The primary flash buffer tank 1 is equipped with an AISA analysis and display interlock alarm and an AIT analysis and display transmitter. The AISA analysis and display interlock alarm is used to measure the properties of the fluid medium and convert the analysis results into a standard electrical signal. The AIT analysis and display transmitter integrates "medium characteristic analysis, result display, over-limit alarm, and interlock control" to ensure that the medium characteristics meet the process requirements.

[0030] In one embodiment, the gas phase pressure at the outlet of compressor 2 is above 0.2 MPa.

[0031] A pressure interlock control system, including a PISA pressure display interlock alarm, is installed between the pipeline connecting the gas phase outlet and compressor 2 and the gas inlet manifold. The control system also includes a PIT pressure transmitter. The PIT pressure transmitter is manually operated by the operator via an HS manual switch, and the current status is displayed by a UI switch status indicator.

[0032] The gas manifold is also equipped with a TI thermometer and a TIT temperature transmitter. The TI thermometer can directly measure and display the temperature of the gas in the gas manifold, while the TIT temperature transmitter converts the "temperature signal" into a standard electrical signal and transmits it to the control room over a long distance.

[0033] In one embodiment, the secondary separation buffer tank 4 is equipped with a make-up gas pipeline connected to an external gas source. The make-up gas pipeline is connected to the incoming gas manifold.

[0034] The gas supply manifold and the secondary separation buffer tank 4 are controlled by pressure interlock to prevent compressor 2 from cavitation or overload, ensuring continuous and stable system operation. In one embodiment, the gas supply line is connected to the secondary separation buffer tank 4 via two pressure regulating valves, and a control valve is installed on the gas supply manifold. The pressure regulating valve and the control valve are interlocked. Specifically, the gas supply line is connected to the secondary separation buffer tank 4 via two PY pressure-electric conversion valves, and one PY pressure-electric conversion valve is installed on the gas supply manifold. The three PY pressure-electric conversion valves are interlocked. The PY pressure-electric conversion valve converts the measured gas pressure signal into an electrical signal and also has a pressure control function. During gas supply, both conversion valves on the gas supply line and the conversion valve on the gas supply manifold are opened to facilitate airflow and maintain gas phase balance after gas supply is completed.

[0035] In one embodiment, when the pressure of the incoming gas manifold is less than or equal to 200 Pa, the pressure regulating valve is opened and gas is supplied through the gas supply line, and the gas from the secondary separation buffer tank 4 enters the incoming gas manifold.

[0036] The gas phase outlet of the secondary separation buffer tank 4 is also connected to the associated gas separator via a FIT flow meter.

[0037] In one embodiment, a PLC control cabinet 6 is also included. The PLC control cabinet 6 is used to collect pressure and liquid level data of each device and upload the data to the control room.

[0038] The volatile gas from the tanks in the station's tank area of ​​this utility model is generated by the gas phase pipeline network 8, which enters the primary flash buffer tank 1 through the PY pressure gas-electric conversion valve and the HY electric valve. After the oxygen content is analyzed and found to be qualified by the oxygen content monitor, the liquid phase and gas phase are initially separated by flash evaporation in the tank. The liquid phase enters the station's gathering and transportation system unit through the sewage pump 12 to ensure the safety and airtightness of the system.

[0039] When the gas phase is pressurized to above 0.2 MPa, the pressurized gas is cooled by the air cooler 3. After being cooled to 40°C, it enters the secondary separation buffer tank 4. After buffering for 5 to 10 minutes, the gas phase enters the gas collection pipeline network 7, and the liquid phase enters the external transmission unit of the station's collection and transmission system. This completes the effect of automatic pressurization and transmission of gas and liquid, which can ensure 99% recovery and utilization of tank gas and solve the problem of lower limit explosion of flammable gas in daily tanks. At the same time, the set-up secondary gas replenishment process solves the problem of insufficient gas replenishment in the tank and the intake of air, making the system more reliable and safe.

[0040] When compressor 2 stops, the secondary separation buffer tank 4 is interlocked with the incoming gas manifold pressure. The make-up gas pipeline is controlled by a pressure regulating valve, which opens when the control pressure is ≤200Pa. The pressure regulating valve (two PY pressure-electric conversion valves) on the make-up gas pipeline opens to make up the gas. The gas in the tank enters the incoming gas manifold, realizing the gas phase balance system.

[0041] This utility model discloses a skid-mounted oilfield volatile gas recovery device, employing a series connection of a primary flash buffer tank 1, a compressor 2, an air cooler 3, and a secondary separation buffer tank 4. Utilizing a two-stage separation process (primary flash buffer tank 1 and secondary separation buffer tank 4), it effectively reduces droplets and impurities carried in the gas phase, improving the operating efficiency of compressor 2. The outlet pressure of compressor 2 is maintained above 0.2 MPa to ensure stable gas delivery in the pipeline network. Air cooler 3 lowers the gas temperature, promoting condensate precipitation, increasing light hydrocarbon recovery rate, and reducing resource waste. This achieves step-by-step purification of volatile gas and condensate recovery, while simultaneously enabling efficient volatile gas recovery and stable system operation. It combines the advantages of energy saving, environmental protection, safety, reliability, and convenient operation and maintenance, making it suitable for resource utilization scenarios of oilfield volatile gas.

[0042] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the technical solution of the present utility model in any way. Those skilled in the art should understand that, without departing from the spirit and principles of the present utility model, the technical solution can be modified and replaced in several simple ways, and these modifications and replacements are all within the scope of protection covered by the claims.

Claims

1. A skid-mounted oilfield volatile gas recovery device, characterized in that, It includes a first-stage flash buffer tank (1), a compressor (2), an air cooler (3) and a second-stage separation buffer tank (4) connected in sequence. The first-stage flash buffer tank (1) is connected to the volatile gas storage tank through the gas manifold of the gas phase pipeline network (8), and the gas phase outlet of the second-stage separation buffer tank (4) is connected to the gas collection pipeline network (7).

2. The skid-mounted oilfield volatile gas recovery device according to claim 1, characterized in that, An aerobic content detector (10) is connected to the primary flash buffer tank (1).

3. The skid-mounted oilfield volatile gas recovery device according to claim 1, characterized in that, The primary flash buffer tank (1) is equipped with a gas phase outlet and a liquid phase outlet. The liquid phase outlet is connected to the collection and transportation system through a sewage pump (12), and the gas phase outlet is connected to the inlet of the compressor (2).

4. The skid-mounted oilfield volatile gas recovery device according to claim 1, characterized in that, The gas phase pressure at the outlet of compressor (2) is above 0.2 MPa.

5. The skid-mounted oilfield volatile gas recovery device according to claim 1, characterized in that, The secondary separation buffer tank (4) is connected to an external gas source through a gas supply line, which is connected to the incoming gas manifold.

6. The skid-mounted oilfield volatile gas recovery device according to claim 5, characterized in that, The gas manifold and the secondary separation buffer tank (4) are controlled by pressure interlock.

7. The skid-mounted oilfield volatile gas recovery device according to claim 6, characterized in that, The gas supply line is connected to the secondary separation buffer tank (4) via two pressure regulating valves. A control valve is installed on the gas supply manifold, and the pressure regulating valve and the control valve are interlocked.

8. The skid-mounted oilfield volatile gas recovery device according to claim 7, characterized in that, When the pressure in the gas manifold is less than or equal to 200 Pa, the pressure regulating valve opens to supply gas through the gas supply line, and the gas from the secondary buffer tank enters the gas manifold.

9. The skid-mounted oilfield volatile gas recovery device according to claim 1, characterized in that, The condensate outlet (9) of the secondary separation buffer tank (4) is connected to the oil and gas system.

10. The skid-mounted oilfield volatile gas recovery device according to claim 1, characterized in that, It also includes a PLC control cabinet (6), which is used to collect pressure and liquid level data of each device and upload the data to the control room.

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