A decarbonization device for recovering carbon dioxide and high-purity helium from a wellhead gas

Abstract

The utility model relates to oil and gas recovery field discloses a kind of decarburization equipment of wellhead gas recovery carbon dioxide and high-purity helium, including primary membrane separation unit, primary permeation gas compressor, secondary membrane separation unit, secondary permeation gas compressor, decarburization equipment, dehydrogenation equipment, dehydration equipment and helium purification equipment, the primary membrane separation unit is connected by pipeline with the air inlet of primary permeation gas compressor, and the air outlet of primary permeation gas compressor is connected by pipeline with secondary membrane separation unit. The decarburization equipment of wellhead gas recovery carbon dioxide and high-purity helium can divide the recovered gas into three materials, which are two types of natural gas, carbon dioxide-rich gas and high-purity helium. The dehydrogenation equipment is filled with noble metal catalyst, which allows hydrogen and oxygen to react at a temperature of 80°C. The helium purification equipment uses molecular sieves for adsorption, ensuring that the helium content is ≥99.999%. This solves the problem of not recovering carbon dioxide and helium.

Description

Technical Field

[0001] This utility model relates to the field of oil and gas recovery technology, specifically a decarbonization device for recovering carbon dioxide and high-purity helium from wellhead gas. Background Technology

[0002] During oil and gas well production, natural gas is produced. If not recovered, it will be burned or released, resulting in waste. Recovering the natural gas at the wellhead and processing it can generate economic benefits. After recovery, the natural gas is separated and pressurized to form liquefied natural gas (LNG) or compressed natural gas (CNG), which is then delivered to users to meet their needs.

[0003] Associated gas produced from oil wells can be recovered and reused through wellhead recovery devices. Natural gas produced from scattered, remote gas wells also needs to be recovered at the wellhead. This is typically done using a natural gas recovery skid at the wellhead to recover and process the natural gas before finally delivering it to users, thus creating value for natural gas production. Currently, wellhead gas recovery only recovers the natural gas itself, while the carbon dioxide and helium are directly emitted into the high atmosphere, resulting in a significant waste of this precious resource.

[0004] There is an urgent need for a decarbonization device for recovering carbon dioxide and high-purity helium from wellhead gas to address the technical deficiencies mentioned above. Utility Model Content

[0005] The purpose of this invention is to provide a decarbonization device for recovering carbon dioxide and high-purity helium from wellhead gas, in order to solve the problem in the background art that only natural gas is recovered, while the carbon dioxide and helium are directly emitted into the high atmosphere, resulting in a great waste of precious resources.

[0006] To achieve the above objectives, this utility model provides the following technical solution: a decarbonization device for recovering carbon dioxide and high-purity helium from wellhead gas, comprising a primary membrane separation unit, a primary permeate compressor, a secondary membrane separation unit, a secondary permeate compressor, a decarbonization device, a dehydrogenation device, a dehydration device, and a helium purification device. The primary membrane separation unit is connected to the inlet of the primary permeate compressor via a pipeline, the outlet of the primary permeate compressor is connected to the secondary membrane separation unit via a pipeline, the secondary membrane separation unit is connected to the inlet of the secondary permeate compressor via a pipeline, the output of the secondary permeate compressor is connected to the decarbonization device via a pipeline, the decarbonization device is connected to the dehydrogenation device via a pipeline, the dehydrogenation device is connected to the dehydration device via a pipeline, and the dehydration device is connected to the helium purification device via a pipeline.

[0007] As a further technical solution of this utility model, both the primary membrane separation unit and the secondary membrane separation unit adopt high-pressure membranes, and the pressure difference across the membrane is no greater than 4.5 MPaG.

[0008] As a further technical solution of this utility model, the inlet pressure of the first-stage permeate compressor and the second-stage permeate compressor is 0.01-0.05 MPaG, and the outlet pressure is set to 3-4.5 MPaG.

[0009] As a further technical solution of this utility model, the separation groups of the primary membrane separation unit and the secondary membrane separation unit are both composed of a single membrane or multiple membranes.

[0010] As a further technical solution of this utility model, the decarbonization equipment is filled with molecular sieve catalyst, which only adsorbs carbon dioxide, while methane, hydrogen and helium are sent to the dehydrogenation equipment as product gases.

[0011] As a further technical solution of this utility model, the dehydrogenation device is internally filled with a precious metal catalyst, and the helium purification device uses molecular sieves for adsorption.

[0012] Compared with the prior art, the beneficial effects of this utility model are: the decarbonization equipment for recovering carbon dioxide and high-purity helium from wellhead gas not only realizes the function of recovering carbon dioxide and helium and shortening the construction cycle, but also realizes the function of low energy consumption.

[0013] Equipped with a primary membrane separation unit, a secondary membrane separation unit, and a helium purification device, wellhead gas is transported to the wellhead gas treatment unit via a wellhead gas pipeline. The wellhead gas pressure is 3-4.5 MPaG, and the main media are methane, carbon dioxide, hydrogen, and helium. The waste gas originally discharged from the wellhead gas can be separated into three materials by the primary membrane separation unit, the secondary membrane separation unit, and the helium purification device: Class II natural gas, carbon dioxide-rich gas, and high-purity helium, turning waste into treasure. The dehydrogenation device is internally filled with a precious metal catalyst, allowing hydrogen and oxygen to react at a temperature of 80℃. After the dehydrogenation device, the hydrogen content is ≤1ppm. The helium purification device uses molecular sieves for adsorption to ensure that the helium content is ≥99.999%.

[0014] By setting up a primary membrane separation unit and a secondary membrane separation unit, the membrane units of the primary and secondary membrane separation units are all skid-mounted structures. The primary and secondary permeate compressors are screw compressors or piston compressors, and one is set up as a backup. This device adopts a skid-mounted device, and only the foundation and external pipeline connection need to be made on site to start production, which greatly shortens the on-site construction cycle. Attached Figure Description

[0015] Figure 1This is a frontal cross-sectional view of the present invention.

[0016] Figure 2 This is a front view schematic diagram of the primary membrane separation unit and the secondary membrane separation unit of this utility model;

[0017] Figure 3 This is a front view structural diagram of the helium purification device of this utility model;

[0018] Figure 4 This is a front view structural diagram of the decarbonization equipment and dehydrogenation equipment of this utility model.

[0019] In the diagram: 1. Primary membrane separation unit; 2. Primary permeate compressor; 3. Secondary membrane separation unit; 4. Secondary permeate compressor; 5. Decarbonization equipment; 6. Dehydrogenation equipment; 7. Dehydration equipment; 8. Helium purification equipment. Detailed Implementation

[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0021] Please see Figure 1-4 The present invention provides an embodiment of a decarbonization device for recovering carbon dioxide and high-purity helium from wellhead gas, comprising a primary membrane separation unit 1, a primary permeate compressor 2, a secondary membrane separation unit 3, a secondary permeate compressor 4, a decarbonization device 5, a dehydrogenation device 6, a dehydration device 7, and a helium purification device 8. The primary membrane separation unit 1 is connected to the inlet of the primary permeate compressor 2 via a pipeline, the outlet of the primary permeate compressor 2 is connected to the secondary membrane separation unit 3 via a pipeline, the secondary membrane separation unit 3 is connected to the inlet of the secondary permeate compressor 4 via a pipeline, the output end of the secondary permeate compressor 4 is connected to the decarbonization device 5 via a pipeline, the decarbonization device 5 is connected to the dehydrogenation device 6 via a pipeline, the dehydrogenation device 6 is connected to the dehydration device 7 via a pipeline, and the dehydration device 7 is connected to the helium purification device 8 via a pipeline.

[0022] The separation units of both the primary membrane separation unit 1 and the secondary membrane separation unit 3 are composed of a single membrane or multiple membranes;

[0023] Specifically, such as Figure 1 and Figure 2As shown, the wellhead gas, with a pressure of 4.2 MPaG and a temperature of approximately 40°C, is delivered to the outside of the unit's boundary. It enters the wellhead gas primary membrane separation unit 1 within the unit; this unit is a skid-mounted assembly. The primary membrane separation unit 1 is equipped with a membrane separator. Hydrogen, helium, and carbon dioxide are fast gases during this separation process. The non-permeable gas in the primary membrane separation unit 1 mainly consists of methane. After passing through the primary membrane separation unit 1, the material pressure is 4.1 MPaG, and the product quality meets the Class II natural gas standard before being delivered outside the boundary.

[0024] Furthermore, the primary permeate gas is compressed to 4.3 MPa by the primary permeate gas compressor 2 and enters the secondary membrane separation unit 3. The secondary membrane separation unit 3 is equipped with a membrane separator. Hydrogen, helium and carbon dioxide are fast gases in this membrane separation process. The secondary non-permeate gas is returned to the primary membrane separation unit 1 and mixed with the wellhead gas for further enrichment to increase the methane recovery rate.

[0025] Both the primary membrane separation unit 1 and the secondary membrane separation unit 3 use high-pressure membranes, with a pressure difference of no more than 4.5 MPaG across the membrane. The inlet pressure of the primary permeate compressor 2 and the secondary permeate compressor 4 is 0.01 to 0.05 MPaG, and the outlet pressure is set to 3 to 4.5 MPaG.

[0026] Specifically, such as Figure 1 and Figure 4 As shown, the secondary permeate gas is compressed to 1.8 MPa by the secondary permeate gas compressor 4 and then enters the decarbonization equipment 5. The decarbonization equipment 5 is equipped with 3-5 adsorption tanks, which are filled with a special catalyst for decarbonization and adsorption of carbon dioxide, adsorbing only carbon dioxide. The desorbed gas from the decarbonization equipment 5 is rich in carbon dioxide and is sent to the subsequent unit.

[0027] The decarbonization equipment 5 is filled with molecular sieve catalyst, which only adsorbs carbon dioxide. Methane, hydrogen and helium are sent to the dehydrogenation equipment 6 as product gases. The dehydrogenation equipment 6 is filled with precious metal catalyst. The helium purification equipment 8 uses molecular sieve for adsorption.

[0028] Specifically, such as Figure 1 and Figure 3 As shown, the gas pressure after decarbonization unit 5 is 1.7 MPaG and is sent to dehydrogenation unit 6. Hydrogen is removed from the decarbonized gas through catalytic combustion, ensuring that the hydrogen content in the catalytic dehydrogenation unit is ≤1 ppm. Then it is sent to dehydration unit 7, which consists of three drying tanks filled with silica gel desiccant. The dew point of the material after dehydration unit 7 reaches -70℃. The dehydrated gas is then sent to helium purification unit 8, which removes nitrogen, oxygen, and methane from the crude helium gas, achieving a helium concentration of 99.999%, before being sent to subsequent units for filling.

[0029] Working Principle: Wellhead gas at a pressure of 4.2 MPaG and a temperature of approximately 40°C is delivered to the outside of the unit's boundary. It enters the first-stage membrane separation unit 1, a skid-mounted unit. The first-stage membrane separation unit 1 is equipped with a membrane separator. Hydrogen, helium, and carbon dioxide are fast gases during this separation process. The non-permeable gas in the first-stage membrane separation unit 1 mainly contains methane. After passing through the first-stage membrane separation unit 1, the material pressure is 4.1 MPaG, and the product quality meets the Class II natural gas standard, and is then delivered outside the boundary. The first-stage permeable gas is compressed to 4.3 MPa by the first-stage permeable gas compressor 2 and enters the second-stage membrane separation unit 3. The second-stage membrane separation unit 3 is equipped with a membrane separator. Hydrogen, helium, and carbon dioxide are fast gases during this separation process. The second-stage non-permeable gas returns to the first-stage membrane separation unit 1, mixes with the wellhead gas, and is further concentrated to increase the methane recovery rate. The secondary permeate gas is compressed to 1.8 MPa by the secondary permeate gas compressor 4 and enters the decarbonization unit 5. The decarbonization unit 5 has 3-5 adsorption tanks filled with a dedicated catalyst for carbon dioxide removal, adsorbing only carbon dioxide. The desorbed gas from the decarbonization unit 5 is rich in carbon dioxide and is sent to the next unit. The gas pressure after the decarbonization unit 5 is 1.7 MPaG and is sent to the dehydrogenation unit 6. Hydrogen is removed from the decarbonized gas through catalytic combustion, ensuring that the hydrogen content in the catalytic dehydrogenation unit is ≤1 ppm. Then it is sent to the dehydration unit 7, which consists of three drying tanks filled with silica gel desiccant. The dew point of the material after dehydration unit 7 reaches -70℃. The dehydrated gas is sent to the helium purification unit 8, which removes nitrogen, oxygen, and methane from the crude helium gas, achieving a helium concentration of 99.999%, before being sent to the next unit for filling.

[0030] No waste gas, wastewater, or solid waste is generated during normal operation of this process equipment. Only the gas emitted during start-up, shutdown, or emergency conditions is sent to the original flare for combustion.

[0031] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A decarbonization device for recovering carbon dioxide and high-purity helium from wellhead gas, comprising a primary membrane separation unit (1), a primary permeate compressor (2), a secondary membrane separation unit (3), a secondary permeate compressor (4), a decarbonization device (5), a dehydrogenation device (6), a dehydration device (7), and a helium purification device (8), characterized in that: The primary membrane separation unit (1) is connected to the inlet of the primary permeate compressor (2) via a pipe. The outlet of the primary permeate compressor (2) is connected to the secondary membrane separation unit (3) via a pipe. The secondary membrane separation unit (3) is connected to the inlet of the secondary permeate compressor (4) via a pipe. The output of the secondary permeate compressor (4) is connected to the decarbonization device (5) via a pipe. The decarbonization device (5) is connected to the dehydrogenation device (6) via a pipe. The dehydrogenation device (6) is connected to the dehydration device (7) via a pipe. The dehydration device (7) is connected to the helium purification device (8) via a pipe.

2. The decarbonization equipment for recovering carbon dioxide and high-purity helium from wellhead gas according to claim 1, characterized in that: Both the primary membrane separation unit (1) and the secondary membrane separation unit (3) use high-pressure membranes, and the pressure difference across the membrane is no greater than 4.5 MPaG.

3. The decarbonization equipment for recovering carbon dioxide and high-purity helium from wellhead gas according to claim 1, characterized in that: The separation units of the primary membrane separation unit (1) and the secondary membrane separation unit (3) are both composed of a single membrane or multiple membranes.

4. The decarbonization equipment for recovering carbon dioxide and high-purity helium from wellhead gas according to claim 1, characterized in that: The decarbonization equipment (5) is filled with molecular sieve catalyst, which only adsorbs carbon dioxide, while methane, hydrogen and helium are sent to the dehydrogenation equipment (6) as product gases.

5. The decarbonization equipment for recovering carbon dioxide and high-purity helium from wellhead gas according to claim 1, characterized in that: The dehydrogenation device (6) is internally filled with a precious metal catalyst, and the helium purification device (8) uses molecular sieves for adsorption.

6. The decarbonization equipment for recovering carbon dioxide and high-purity helium from wellhead gas according to claim 1, characterized in that: The inlet pressure of the first-stage permeate compressor (2) and the second-stage permeate compressor (4) is 0.01 to 0.05 MPaG, and the outlet pressure is set to 3 to 4.5 MPaG.

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