Flare gas recovery device

Abstract

The utility model discloses a flare gas recovery device which comprises a Venturi tube, a flare liquid separation tank, a flare head, a pressure relief pipe, a fuel gas compressor, a supply pipeline and an output pipeline, an inlet of the flare liquid separation tank is used for receiving flare gas, a gas phase outlet of the flare liquid separation tank is communicated with the flare head through the pressure relief pipe, a first one-way valve is arranged on the pressure relief pipe, and a second one-way valve is arranged on the fuel gas compressor. The input end of the gas compressor is connected with a supply pipeline, the output end of the gas compressor is connected with an output pipeline, the input end of the Venturi tube is communicated with the output pipeline through a first bypass pipe, the suction end of the Venturi tube is communicated with the output end of the torch liquid separation tank through a second bypass pipe, and the output end of the Venturi tube is communicated with the supply pipeline through a third bypass pipe. A second one-way valve is arranged on the third bypass pipe, a fourth bypass pipe communicated with the input end of the torch liquid separation tank is arranged on the supply pipeline, and a pressure control valve is arranged on the fourth bypass pipe. According to the device, flare gas can be recycled, and direct combustion emission of the flare gas is reduced.

Description

Technical Field

[0001] The utility model relates to the field of flare gas recovery, in particular to a flare gas recovery device. Background Art

[0002] Fuel gas refers to gaseous combustible substances that can generate heat energy or power. In industry, there are two main types of fuel gas: natural gas fuel and artificial gas fuel. Both are clean and high-quality energy.

[0003] The flare gas from oil and gas production facilities, also known as fuel gas, is mainly composed of a mixture of hydrocarbon gases, mainly paraffinic low-molecular saturated hydrocarbons, and a small amount of non-hydrocarbon gases. These gases mainly come from the gas produced from gas fields and the associated gas produced simultaneously during the oil production process in oil fields. Its components are mainly methane and a small amount of ethane, propane, butane, pentadecane and above hydrocarbon gases, and may contain non-hydrocarbon gases such as carbon dioxide, water vapor, and hydrogen sulfide.

[0004] In the past, after simple gas-liquid separation, this type of flare gas is often discharged directly into the atmosphere through a cold venting system above the platform deck to prevent the flare gas from covering the air above the oil and gas production facilities. Or, when its flow accumulates to a certain level, it is burned through the ignition plate of the flare head. Whether the flare gas is discharged directly into the atmosphere or discharged into the atmosphere after combustion, the following problems will occur:

[0005] 1. Flare gas is discharged through cold venting, which easily accumulates combustible gas and toxic and harmful gas above oil and gas production facilities, causing atmospheric pollution and harm to oil and gas field operators. Especially in windless weather conditions, it will cause great danger to the personnel and equipment facilities of oil and gas production facilities;

[0006] 2. Flare gas is discharged through combustion. Although it reduces toxic and harmful gases such as hydrogen sulfide and combustible bodies, it will produce a large amount of carbon dioxide, increase greenhouse effect, and fail to achieve resource conversion and utilization, resulting in a large amount of resource waste;

[0007] 4. When the flare gas is directly burned using the flare head, a high-temperature flame will be generated. Long-term burning can easily lead to high-temperature aging of the flare head. At the same time, because the flare head is generally installed at a height of dozens or even hundreds of meters above the platform deck, not only is the flare head replacement operation difficult, but the high-altitude operation also puts a great test on the workers' physical and mental health. It will also cause greater heat radiation to the workers on the oil and gas production facilities, thereby increasing the labor intensity of the workers. Summary of the invention

[0008] The utility model aims to provide a flare gas recovery device, which can realize the recycling of flare gas, reduce carbon emissions generated by direct combustion of flare gas, avoid atmospheric environmental pollution caused by flare gas cooling and venting, and produce extremely high economic benefits.

[0009] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0010] A flare gas recovery device comprises a flare gas conveying mechanism, a fuel gas conveying mechanism and a venturi tube, the flare gas conveying mechanism comprises a flare liquid separator, a flare head and a pressure relief pipe, the inlet of the flare liquid separator is used to receive the flare gas, the gas phase outlet of the flare liquid separator is connected with the flare head through the pressure relief pipe, the pressure relief pipe is provided with a first one-way valve, the fuel gas conveying mechanism comprises a fuel gas compressor, a supply pipeline and an output pipeline, the input end of the fuel gas compressor is connected with the supply pipeline, the output end of the fuel gas compressor is connected with the output pipeline, the input end of the venturi tube is connected with the output pipeline through a first bypass pipe, the suction end of the venturi tube is connected with the output end of the flare liquid separator through a second bypass pipe, the output end of the venturi tube is connected with the supply pipeline through a third bypass pipe, the third bypass pipe is provided with a second one-way valve, the supply pipeline is provided with a fourth bypass pipe connected with the input end of the flare liquid separator, and the fourth bypass pipe is provided with a pressure control valve.

[0011] Furthermore, the supply pipeline is provided with a front scrubber, the input end of the front scrubber is connected to the third bypass pipe, the output end of the front scrubber is connected to the input end of the fuel gas compressor through the first fuel gas delivery main pipe, and the fourth bypass pipe is connected to the first fuel gas delivery main pipe.

[0012] Furthermore, a pressure sensor is provided in the front scrubber tank, and the pressure sensor is connected to the pressure control valve signal.

[0013] Furthermore, an on-off control valve is provided on the first bypass pipe, and the on-off control valve is connected to the pressure sensor signal.

[0014] Furthermore, the output pipeline is provided with a post-scrubbing tank, the input end of the post-scrubbing tank is connected to the output end of the fuel gas compressor through a second fuel gas delivery main pipe, and the first bypass pipe is connected to the second fuel gas delivery main pipe.

[0015] Furthermore, it also includes a turbine generator set, and the input end of the turbine generator set is connected to the output end of the post-gas scrubber.

[0016] Furthermore, the supply pipeline is also provided with a fuel gas cooler, and the fuel gas cooler and the input end of the front scrubber are communicated with each other through a third fuel gas delivery main pipe.

[0017] Furthermore, the pressure relief pipe is provided with a branch pipe arranged in parallel therewith, and a bursting piece is provided on the branch pipe.

[0018] Beneficial effects of the utility model:

[0019] 1. This device can safely, conveniently and quickly recover flare gas, and reuse it as fuel for combustion, generating extremely high economic benefits, and providing a technical basis for green oilfield construction, the realization of dual carbon goals and high-quality development of oilfields.

[0020] 2. There is no need to use cold venting to discharge the flare gas, which can avoid atmospheric pollution and the harm of flare gas to oil and gas field operators.

[0021] 3. Greatly reduce the number of times the flare head is used, thereby reducing the carbon emissions generated by the direct combustion of flare gas, slowing down the aging of the flare head, avoiding long-term large heat radiation to operators on oil and gas production facilities, and reducing the labor intensity of oil and gas field operators. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The utility model is a structural schematic diagram of a flare gas recovery device. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present utility model will be described below in conjunction with the accompanying drawings.

[0024] like Figure 1 As shown, a flare gas recovery device includes a flare gas delivery mechanism, a fuel gas delivery mechanism and a venturi tube 8, the flare gas delivery mechanism includes a flare liquid separator 1, a flare head 2 and a pressure relief pipe 3, the inlet of the flare liquid separator 1 is used to receive the flare gas, the gas phase outlet of the flare liquid separator 1 is connected to the flare head 2 through the pressure relief pipe 3, the pressure relief pipe 3 is provided with a first non-return valve 4, the fuel gas delivery mechanism includes a fuel gas compressor 5, a supply pipeline 6 and an output pipeline 7, the input end of the fuel gas compressor 5 is connected to the supply pipeline 6, the The output end of the fuel gas compressor 5 is connected to the output pipeline 7, the input end of the venturi tube 8 is connected to the output pipeline 7 through the first bypass pipe 9, the suction end of the venturi tube 8 is connected to the output end of the flare liquid separation tank 1 through the second bypass pipe 10, the output end of the venturi tube 8 is connected to the supply pipeline 6 through the third bypass pipe 11, the third bypass pipe 11 is provided with a second one-way valve 12, the supply pipeline 6 is provided with a fourth bypass pipe 13 connected to the input end of the flare liquid separation tank 1, and the fourth bypass pipe 13 is provided with a pressure control valve 14.

[0025] In this embodiment, the flare gas from the oil and gas production facility is introduced into the flare separator 1, which is used to separate the flare gas into gas and liquid phases. The flare gas is generated into a cleaner flare gas after the flare separator 1 captures water. At the same time, the fuel gas is transported to the fuel gas compressor 5 through the supply pipeline 6, and is formed into a high-pressure gas after being pressurized by the fuel gas compressor 5. It is then output through the output pipeline 7. When the fuel gas flows in the output pipeline 7, a small part of the fuel gas will flow into the first bypass pipe 9 through the first bypass pipe 9. To the venturi tube 8, the venturi tube 8 has the function of forming a vacuum negative pressure. The venturi tube 8 will cause the fuel gas to be ejected at a high speed through its output end, so that the pressure energy is converted into velocity energy. The area at the output end of the venturi tube 8 will form a vacuum negative pressure, so that the flare gas in the flare liquid separation tank 1 is extracted through the second bypass pipe 10, so that the two fluids are mixed and energy is exchanged in the venturi tube 8, and the velocity energy is converted into pressure energy. Finally, it is transported to the supply pipeline 6 through the third bypass pipe 11, and the flare gas enters the fuel gas transportation mechanism;

[0026] It should be noted that, since the fluid will produce a strong throttling effect when passing through the venturi tube 8, there will be a large pressure difference between the output pipeline 7 and the venturi tube 8, which will cause a large change in the flow rate and pressure of the fuel gas delivery mechanism. The device connects the output end of the venturi tube 8 to the supply pipeline 6 through the third bypass pipe 11, which can compensate for the fuel gas flow in the supply pipeline 6, thereby ensuring the normal operation of the fuel gas compressor 5 and the normal distribution and use of the subsequent fuel gas; during the use of the device, the venturi tube 8 is in a long-term uninterrupted working state, and the flare gas in the flare separator tank 1 will be continuously extracted. When the flare gas entering the flare separator tank 1 is less, the flare separator tank 1 and the pressure relief pipe 3 will be in a negative pressure state at this time, This device is provided with a fourth bypass pipe 13 between the supply pipeline 6 and the flare liquid separator 1. When there is a large pressure difference between the supply pipeline 6 and the flare liquid separator 1, the pressure control valve 14 will open, and the fuel gas will be introduced into the flare liquid separator 1 through the fourth bypass pipe 13, so that a certain amount of gas is stored inside the flare liquid separator 1, and the flare liquid separator 1 and the pressure relief pipe 3 are prevented from being deformed due to a large negative pressure. The first one-way valve 4 prevents the external air from flowing back into the flare liquid separator 1 through the flare head 2 due to the negative pressure factor, so that the flare gas is always kept inert, and the flare gas and air are prevented from mixing to form an explosive mixed gas. The main function of the flare head 2 is: when too much flare gas is introduced into the flare liquid separator 1, the excess gas is burned and discharged by the flare head 2;

[0027] It should be noted that when the flow rate of the fuel gas received by the supply pipeline 6 increases, the pressure control valve 14 will open, and the excess gas that is greater than the processing capacity of the fuel gas delivery mechanism will be discharged into the flare liquid separation tank 1 through the fourth bypass pipe 13, while providing gas volume for the flare liquid separation tank 1, ensuring the normal delivery and processing of the fuel gas by the fuel gas delivery mechanism;

[0028] It can be understood that the function of the second one-way valve 12 is to prevent the fluid from flowing in the reverse direction through the output end and the suction end of the venturi tube 8 to the flare gas delivery mechanism for discharge, thereby ensuring the normal recycling of the flare gas and avoiding waste of resources.

[0029] The supply pipeline 6 is provided with a front scrubber 15, the input end of the front scrubber 15 is connected to the third bypass pipe 11, the output end of the front scrubber 15 is connected to the input end of the fuel gas compressor 5 through the first fuel gas delivery main pipe 16, and the fourth bypass pipe 13 is connected to the first fuel gas delivery main pipe 16. The front scrubber 15 is used to receive and store fuel gas and a mixed gas of fuel gas and flare gas, and to deliquate the fuel gas, and then distribute it to the fuel gas compressor 5 and the fourth bypass pipe 13 according to the current flow and pressure state of the system.

[0030] The front scrubber tank 15 is provided with a pressure sensor 17, and the pressure sensor 17 is connected to the pressure control valve 14 by signal. The pressure sensor 17 is used to detect the gas pressure inside the front scrubber tank 15, and controls the opening or closing of the pressure control valve 14 according to the gas pressure inside the front scrubber tank 15, so as to ensure the normal delivery and processing of the fuel gas by the fuel gas delivery mechanism.

[0031] The first bypass pipe 9 is provided with an on-off control valve 18, which is connected to the pressure sensor 17 by signal. When the pressure sensor 17 detects that the gas pressure inside the front scrubber 15 increases, that is, the gas flow of the fuel gas increases, if the gas pressure is higher than the set value of the pressure sensor 17, the pressure control valve 14 will be opened, and the on-off control valve 18 will be closed synchronously, and no high-pressure gas source will be injected into the input end of the venturi tube 8, and the venturi tube 8 will be placed in a stopped working state. The excess gas that is greater than the processing capacity of the fuel gas delivery mechanism will be discharged into the flare liquid separation tank 1 through the fourth bypass pipe 13; when the pressure sensor 17 detects that the gas pressure inside the front scrubber 15 increases, the pressure sensor 17 will open the pressure control valve 14, and the on-off control valve 18 will be closed synchronously, and the input end of the venturi tube 8 will not have a high-pressure gas source injected, and the venturi tube 8 will be placed in a stopped working state. The excess gas that is greater than the processing capacity of the fuel gas delivery mechanism will be discharged into the flare liquid separation tank 1 through the fourth bypass pipe 13; When the gas pressure decreases and the gas flow rate decreases, the pressure control valve 14 is closed, and the opening and closing control valve 18 is opened synchronously to resume the operation of the venturi tube 8; the combination design of the pressure sensor 17, the pressure control valve 14, and the opening and closing control valve 18 is designed to give priority to controlling the pressure inside the flare liquid separation tank 1 and the front scrubber tank 15 within a suitable range, and then use the venturi tube 8 to recover and mix the flare gas, so as to ensure the normal operation of the flare gas delivery mechanism and the fuel gas delivery mechanism, and also ensure the safety and stability of the flare gas recovery and mixing.

[0032] The output pipeline 7 is provided with a post-scrubbing tank 19, the input end of the post-scrubbing tank 19 is connected to the output end of the fuel gas compressor 5 through the second fuel gas delivery main pipe 20, and the first bypass pipe 9 is connected to the second fuel gas delivery main pipe 20. The post-scrubbing tank 19 is used to store the mixed gas of the fuel gas and the flare gas, and to perform secondary deliquescence treatment of the gas to ensure that the subsequent equipment can obtain sufficient combustible gas.

[0033] It also includes a turbine generator set 21, the input end of which is connected to the output end of the post-gas scrubber 19. The fuel gas and the mixed combustion gas with the flare gas are supplied to the turbine generator set 21 for power generation.

[0034] The supply pipeline 6 is also provided with a gas cooler 22, and the gas cooler 22 is connected to the input end of the front scrubber 15 through a third fuel gas delivery pipe 23. The gas cooler 22 is used for cooling the fuel gas, and the fuel gas is then input into the interior of the front scrubber 15 through the third fuel gas delivery pipe 23 after cooling.

[0035] The pressure relief pipe 3 is provided with a branch pipe 24 arranged in parallel therewith, and the branch pipe 24 is provided with a bursting disc 25. The branch pipe 24 is arranged in a bypass of the pressure relief pipe 3, and the bursting disc 25 is configured so that the excess flare gas can be discharged through the flare head 2, stabilizing the gas pressure inside the flare gas delivery mechanism and increasing the safety protection redundancy.

Claims

1. A flare gas recovery device, comprising a flare gas delivery mechanism, a fuel gas delivery mechanism and a venturi tube (8), characterized in that: The flare gas delivery mechanism comprises a flare liquid separator (1), a flare head (2) and a pressure relief pipe (3); the inlet of the flare liquid separator (1) is used to receive the flare gas; the gas phase outlet of the flare liquid separator (1) is connected to the flare head (2) via the pressure relief pipe (3); the pressure relief pipe (3) is provided with a first non-return valve (4); the fuel gas delivery mechanism comprises a fuel gas compressor (5), a supply pipeline (6) and an output pipeline (7); the input end of the fuel gas compressor (5) is connected to the supply pipeline (6); the output end of the fuel gas compressor (5) is connected to the output pipeline (7); The input end of the Venturi tube (8) is connected to the output pipeline (7) through a first bypass pipe (9), the suction end of the Venturi tube (8) is connected to the output end of the flare liquid separation tank (1) through a second bypass pipe (10), the output end of the Venturi tube (8) is connected to the supply pipeline (6) through a third bypass pipe (11), the third bypass pipe (11) is provided with a second one-way valve (12), the supply pipeline (6) is provided with a fourth bypass pipe (13) connected to the input end of the flare liquid separation tank (1), and the fourth bypass pipe (13) is provided with a pressure control valve (14).

2. The flare gas recovery device according to claim 1, characterized in that: The supply pipeline (6) is provided with a front scrubber (15), the input end of the front scrubber (15) is connected to the third bypass pipe (11), the output end of the front scrubber (15) is connected to the input end of the fuel gas compressor (5) through a first fuel gas delivery main pipe (16), and the fourth bypass pipe (13) is connected to the first fuel gas delivery main pipe (16).

3. The flare gas recovery device according to claim 2, characterized in that: A pressure sensor (17) is provided in the front scrubber tank (15), and the pressure sensor (17) is signal-connected to the pressure control valve (14).

4. The flare gas recovery device according to claim 3, characterized in that: The first bypass pipe (9) is provided with an on-off control valve (18), and the on-off control valve (18) is connected to the pressure sensor (17) for signal transmission.

5. The flare gas recovery device according to claim 2, 3 or 4, characterized in that: The output pipeline (7) is provided with a post-scrubbing tank (19), the input end of the post-scrubbing tank (19) is connected to the output end of the fuel gas compressor (5) through a second fuel gas delivery main pipe (20), and the first bypass pipe (9) is connected to the second fuel gas delivery main pipe (20).

6. The flare gas recovery device according to claim 5, characterized in that: It also includes a turbine generator set (21), wherein the input end of the turbine generator set (21) is connected to the output end of the post-gas scrubber (19).

7. The flare gas recovery device according to claim 6, characterized in that: The supply pipeline (6) is also provided with a fuel gas cooler (22), and the fuel gas cooler (22) and the input end of the front scrubber tank (15) are connected to each other via a third fuel gas delivery main pipe (23).

8. The flare gas recovery device according to claim 1, characterized in that: The pressure relief pipe (3) is provided with a branch pipe (24) arranged in parallel therewith, and a bursting disc (25) is provided on the branch pipe (24).

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