Application of bursting needle valve and liquid ring compressor to recover scattered flare gas system of offshore platform

Abstract

The utility model discloses a system for recovering scattered flare gas from offshore platforms using a bursting needle valve and a liquid ring compressor, comprising a flare liquid separation tank, which is connected in sequence to a pressure regulating part and a flare gas combustion part through a pipeline, wherein the pressure regulating part comprises a pressure regulating valve, a quick-opening valve, and a bursting needle valve arranged in parallel; the outlet pipeline of the flare liquid separation tank is also connected to a gas pressurizing part, which comprises a liquid ring compressor. The utility model can replace the conventional scheme of recovering scattered flare gas from offshore platforms using a water seal tank and a jet supercharger, reduce flare gas emissions during the development and production of oil production platforms, and achieve emission reduction and carbon reduction targets.

Description

Technical Field

[0001] The utility model relates to the technical field of offshore oil engineering, in particular to a system for recovering scattered flare gas from an offshore platform by using a bursting needle valve and a liquid ring compressor. Background Art

[0002] Offshore oil production platforms are usually equipped with a flare venting system. The gas from the oil and gas processing system and the gas from the closed exhaust system enters the flare separation tank through the flare manifold. The gas after separation enters the flare head for combustion to meet the platform's safety production requirements. However, the combustion of the above-mentioned flare gas causes a waste of some resources. Offshore oil production platforms should carry out deep recovery and treatment of flare gas. The current deep flare gas recovery technologies used by offshore oil production platforms are mainly water seal tank recovery methods and jet booster recovery methods, which have the following limitations: (1) The available space on the offshore platform is limited, and it is impossible to set up large buffer gas tanks and water seal tanks. The procedures for expanding the deck are complicated and costly. (2) The water seal tank pressure control method is single, which may affect the emergency discharge function of the system under fault conditions. (3) The jet booster requires a high-pressure gas source as a power source, which has problems such as large energy loss and high energy consumption.

[0003] In order to overcome the above shortcomings, it is necessary to develop an economical and reliable scattered flare gas deep recovery system suitable for offshore oil production platforms to replace the conventional solution of using water seal tanks and jet boosters to recover scattered flare gas from offshore platforms. Utility Model Content

[0004] In order to solve the above technical problems, the utility model provides a system for recovering scattered flare gas from offshore platforms using a bursting needle valve and a liquid ring compressor, so as to replace the conventional solution of recovering scattered flare gas from offshore platforms using a water seal tank and a jet booster, thereby reducing flare gas emissions during the development and production of oil production platforms and achieving emission reduction and carbon reduction targets.

[0005] The utility model is realized by adopting the following technical solutions.

[0006] A system for recovering scattered flare gas from an offshore platform using a bursting needle valve and a liquid ring compressor, comprising a flare liquid separator tank, which is connected in sequence to a pressure regulating part and a flare gas combustion part through a pipeline, wherein the pressure regulating part comprises a pressure regulating valve, a quick-opening valve, and a bursting needle valve arranged in parallel; the outlet pipeline of the flare liquid separator tank is also connected to a gas pressurizing part, which comprises a liquid ring compressor.

[0007] Furthermore, the liquid ring compressor is connected to a gas scrubber.

[0008] Furthermore, the flare gas combustion part includes a plasma ignition torch, and an oxygen analyzer and a flow meter are also provided on the pipeline connecting the plasma ignition torch and the pressure regulating part.

[0009] Furthermore, the system also includes an intelligent control unit, which includes a central control system, and the central control system is connected to the pressure sensor, the quick-opening valve, the pressure regulating valve and the liquid ring compressor via a communication cable.

[0010] Furthermore, the pressure sensor is installed on the top of the flare liquid separation tank.

[0011] The utility model obtains the following beneficial effects.

[0012] (1) The system of the utility model has a simple structure, a small volume, and a light added weight, which meets the requirements for installation under limited space conditions on offshore oil production platforms;

[0013] (2) The utility model not only reduces the pollution caused by the combustion of flare gas by recycling the flare gas, but also can be used as a fuel gas system for the energy supply platform;

[0014] (3) The utility model does not affect the emergency discharge function, the equipment reliability is relatively high, and the maintenance cycle is long;

[0015] (4) The bursting needle valve used in the utility model can be closed after being reset and does not need to be replaced;

[0016] (5) The liquid ring compressor used in the present invention has an obvious pressurizing effect and low energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a connection diagram of the system of the utility model.

[0018] Among them: 1. Torch liquid separation tank; 2. Torch manifold; 3. Pressure regulating part; 4. Pressure regulating valve; 5. Quick opening valve; 6. Bursting needle valve; 7. Liquid ring compressor; 8. Plasma immediate ignition torch; 9. Gas scrubber; 10. Pressure sensor; 11. Flow meter; 12. Oxygen content analyzer; 13. Central control system; 14. Communication cable. DETAILED DESCRIPTION

[0019] The technical solution of the utility model will be clearly and completely described below through specific implementation methods.

[0020] like Figure 1 As shown, a system for recovering scattered flare gas from an offshore platform using a bursting needle valve and a liquid ring compressor includes a flare liquid separation tank 1, a pressure regulating part 3, a gas pressurizing part, a flare gas combustion part and an intelligent control unit.

[0021] The pressure regulating part 3 includes a pressure regulating valve 4, a quick-opening valve 5, a bursting needle valve 6 and its affiliated valves and pipelines arranged in parallel. The pressure regulating valve 4, the quick-opening valve 5 and the bursting needle valve 6 are respectively installed on three sub-pipelines connected in parallel. One end of the sub-pipeline is connected to the outlet pipeline of the flare liquid separator 1, and the other end is connected to the plasma ignition torch 8 through a pipeline; the gas boosting part includes a liquid ring compressor 7 and its affiliated pipelines; the flare gas combustion part includes a plasma ignition torch 8, a flow meter 11, an oxygen analyzer 12 and its affiliated pipelines; the intelligent control unit collects signals from the pressure regulating part 3 and the gas boosting part through the pressure sensor 10, and transmits them to the offshore production platform central control system 13 through the communication cable 14 and controls the pressure regulating part 3 and the gas boosting part. The central control system 13 refers to the production control system of the platform crude oil, which is also called the central control system in the petrochemical industry. It specifically includes the PCS system, ESD system, and F&G system. Its main function is to achieve real-time monitoring of process parameters, alarm reminders for abnormal conditions, and automatic shutdown under emergency conditions to protect the safety of equipment and personnel.

[0022] Among them, in this embodiment, the gas from the oil and gas processing system and the gas from the closed exhaust system enters the flare separator tank 1 and fills the front end of the pressure control valve group through the flare manifold 2. The pressure regulating part 3 installs a pressure sensor 10 on the top of the existing flare separator tank 1 on the platform, and installs a pressure regulating valve 4, a quick opening valve 5 and a bursting needle valve 6 on the outlet pipeline of the flare separator tank 1, and sets a reasonable opening pressure.

[0023] Among them, in this embodiment, the pressure regulating valve 4 automatically adjusts the valve opening according to the pressure detected by the flare liquid separation tank pressure sensor 10 to maintain the flare manifold within a certain pressure range. The quick-opening valve 5 remains closed under normal working conditions. When it is detected that the flare manifold pressure reaches the valve setting value, the compressor fails and shuts down, or a fire condition occurs, the valve opens quickly, and the flare gas is quickly discharged from this channel. The bursting needle valve 6 remains closed under normal working conditions. When the flare manifold pressure rises to the set pressure, the bursting needle valve opens, and the flare gas is quickly discharged through this channel.

[0024] Among them, in this embodiment, the gas boosting part pressurizes the flare gas through the liquid ring compressor 7 and then enters the platform fuel gas processing process (gas scrubber 9) through the export auxiliary pipeline. The compressor skid is interlocked with the central control ESD emergency stop, public fault, public alarm and unit start and stop signal.

[0025] In this embodiment, a flow meter 11 and a plasma ignition torch 8 are installed on the auxiliary pipeline of the flare gas combustion part. When the flow meter 11 detects the flare gas flow, the control cabinet immediately starts the flash ignition, and the flare gas burns safely.

[0026] In this embodiment, an oxygen analyzer 12 is installed on the auxiliary pipeline, and the shutdown of the compressor is interlocked to effectively prevent air from flowing back into the compressor. The specific implementation method is that the oxygen analyzer detects the oxygen content in the flare gas, and this parameter will be transmitted to the central control system. By setting the control logic in the central control system in advance, for example, when the oxygen content is set to be higher than a certain value, the system executes the compressor shutdown command.

[0027] The model selected for the pressure regulating valve 4 of the present application is AD5 / 700-HGC-6”-150LB; the model selected for the quick-opening valve 5 is V30KS-0300R3A113A1-SGS00Q5Y1G0IB; the model selected for the bursting needle valve 6 is HO-F-12-150; the model selected for the liquid ring compressor 7 is 2BW8500-450; the model selected for the plasma ignition torch 8 is DN300; the range of the pressure sensor 10 is 0-25MPa, and the output signal is 4-20mA+HART; the model selected for the oxygen content analyzer 12 is InPro6850iG.

[0028] The working principle of the utility model is:

[0029] like Figure 1 As shown, under normal production conditions, the flare gas discharged from the platform oil, gas and closed exhaust system enters the flare liquid separator 1, undergoes simple gas-liquid separation, and reaches the front end of the pressure control valve group through the flare manifold 2. Under normal conditions, the pressure regulating valve 4 remains closed to establish the back pressure at the inlet of the liquid ring compressor 7 to ensure the recovery of the flare gas. The liquid ring compressor 7 pressurizes the flare gas and enters the platform fuel gas processing flow.

[0030] When the pressure value detected by the pressure sensor 10 on the flare liquid separator 1 reaches the set value A of the pressure regulating valve 4, the pressure regulating valve 4 opens, and the flare gas is released to the plasma and then ignites the flare 8. At the same time, a quick-opening valve 5 and a bursting needle valve 6 are added to the flare manifold 2. The quick-opening valve 5 is interlocked and controlled by the detection signal of the flare liquid separator 10 and the operation signal of the liquid ring compressor 7. It remains closed under normal working conditions. When the detection signal of the pressure sensor 10 reaches the opening pressure B of the quick-opening valve, the liquid ring compressor 7 is shut down or unloaded, and a fault condition or a fire condition occurs, the quick-opening valve 5 opens quickly, and the flare gas is released to the plasma and then ignites the flare 8. If the quick-opening valve 5 cannot be opened smoothly or is not opened in time, the pressure of the flare liquid separator 1 continues to rise. When it rises to the opening pressure C of the bursting needle valve 6, the bursting needle valve 6 ruptures, and the flare gas is released to the plasma through the bursting needle valve 6 and then ignites the flare 8. Among them, the relationship between the three pressure setting values ​​should be: A<B<C.

[0031] The plasma ignition torch 8 and the blasting needle valve 6 are both universal models, and the pipe specifications thereof are both DN300; the quick-opening valve 5 is a pneumatic quick-opening butterfly valve.

[0032] The embodiments described above are merely descriptions of preferred implementation modes of the present invention, and are not intended to limit the concept and scope of the present invention. Without departing from the design concept of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary engineering and technical personnel in the field should fall within the protection scope of the present invention. The technical contents for which protection is sought in the present invention have been fully recorded in the technical requirements.

Claims

1. A system for recovering scattered flare gas from an offshore platform using a bursting needle valve and a liquid ring compressor, comprising a flare liquid separation tank (1), characterized in that: The flare liquid separation tank (1) is connected to a pressure regulating part (3) and a flare gas combustion part in sequence through a pipeline, wherein the pressure regulating part comprises a pressure regulating valve (4), a quick opening valve (5), and a bursting needle valve (6) arranged in parallel; the outlet pipeline of the flare liquid separation tank (1) is also connected to a gas pressurizing part, and the gas pressurizing part comprises a liquid ring compressor (7).

2. A system for recovering scattered flare gas from offshore platforms using a bursting needle valve and a liquid ring compressor according to claim 1, characterized in that: The liquid ring compressor (7) is connected to a gas scrubber (9).

3. According to claim 1, a system for recovering scattered flare gas from offshore platforms using a bursting needle valve and a liquid ring compressor is characterized in that: The flare gas combustion part comprises a plasma ignition torch (8), and an oxygen analyzer (12) and a flow meter (11) are also provided on a pipeline connecting the plasma ignition torch (8) and the pressure regulating part (3).

4. A system for recovering scattered flare gas from offshore platforms using a bursting needle valve and a liquid ring compressor according to claim 1, characterized in that: The system further comprises an intelligent control unit, wherein the intelligent control unit comprises a central control system (13), and the central control system (13) is connected to the pressure sensor (10), the quick-opening valve (5), the pressure regulating valve (4) and the liquid ring compressor (7) via a communication cable (14).

5. A system for recovering scattered flare gas from offshore platforms using a bursting needle valve and a liquid ring compressor according to claim 4, characterized in that: The pressure sensor (10) is installed on the top of the flare liquid separation tank (1).

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