Novel pressure swing adsorption treatment equipment for oil field wellhead gas
By designing a new type of pressure-switching adsorption treatment equipment for wellhead gas for oilfields, using the adsorption tower circulation system and molecular sieve adsorbent, the problems of nitrogen treatment and methane purification in wellhead gas in the prior art are solved, and efficient gas treatment and energy utilization are achieved.
Patent Information
- Application Number
- CN202421329308.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-12
- Publication Date
- 2025-03-25
- Estimated Expiration
- 2034-06-12
AI Technical Summary
The prior art is difficult to effectively treat and utilize nitrogen in wellhead gas, and cannot efficiently purify and recover methane, resulting in low energy utilization efficiency and environmental pollution.
Design a new type of pressure-switching adsorption treatment equipment for wellhead gas in oil fields, including filtration devices, liquid-gas separators, alkaline washing tanks, methane purification and recovery machines and compressors. The equipment uses a molecular sieve adsorbent to absorb nitrogen and separates it from methane through an adsorption tower circulation system. The nitrogen is extracted from the vacuum pump to achieve purification and recovery of methane.
Effectively remove nitrogen and other impurities in the wellhead gas, improve methane recovery and purity, improve energy utilization efficiency, and reduce environmental pollution.
Smart Images
Figure CN222658257U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of oilfield mining equipment, in particular to a novel pressure swing adsorption processing equipment for oilfield wellhead gas. Background Art
[0002] The gas resources in Shengli area are very limited, accounting for less than 20% of the total natural gas production, and more than 80% of it is associated gas. As the oil field is exploited, the oil production of underground oil reservoirs gradually decreases, further causing the original oil wells to produce a large amount of associated gas, and the gas in the underground oil and gas reservoirs is released to the surface to form wellhead gas, which mainly includes nitrogen, methane, carbon dioxide (CO2), C 2+ Since the nitrogen content in the wellhead gas can be as high as 90%, while the methane content is relatively low, it cannot be directly input into the pipeline network.
[0003] In order to effectively process and utilize these gas resources, protect the environment and improve energy efficiency, the wellhead gas processing methods currently used include cryogenic method and catalytic conversion method.
[0004] Cryogenic process: The raw gas is sent to the compressor for compression to increase the pressure and temperature. The compressed gas enters the refrigerator (usually using refrigerants or refrigeration cycles to reduce the temperature of the gas), and then passes through the expansion valve. The gas enters the low-pressure area from the high-pressure area, thereby expanding and causing the temperature to drop to achieve a deep cooling effect. At low temperatures, the nitrogen and carbon dioxide in the mixed gas have different boiling points or freezing points. They are separated by separation or solidification methods, and the separated methane gas is collected. The disadvantages are: the gas volume, components, and pressure of the wellhead gas are unstable, and the gas volume is too small and discontinuous, the solution is not economical, and there is another technical difficulty. The freezing problem of carbon dioxide is difficult to solve.
[0005] Catalytic conversion process: The raw gas enters the preheater for preheating, and the temperature is increased to reduce the energy demand of the heater and improve the energy efficiency of the entire process. After preheating, it enters the heater and is further heated by an external heating source to the reaction temperature required for catalytic conversion. (During the heating process, waste heat recovery technology can be used to recycle waste heat to further improve energy efficiency). After heating, it enters the catalytic reactor for catalytic conversion reaction. The generated nitrogen and carbon dioxide enter the preheater for reflux heat exchange, and finally enter the cooler for cooling. The gas is cooled by heat exchange with the cooling medium to reduce its temperature and be discharged from the system. The disadvantages are: the gas volume, composition, and pressure of the wellhead gas are unstable, and the gas volume is too small, so methane cannot be recovered. At the same time, due to the discontinuous gas volume, the energy consumption is high.
[0006] Therefore, there is an urgent need to develop a wellhead gas processing device that can process the nitrogen content in the wellhead gas, purify the methane and input it into the pipeline network. Utility Model Content
[0007] In view of the above deficiencies in the prior art, the purpose of the utility model is to provide a new type of pressure swing adsorption processing equipment for oilfield wellhead gas, which can solve the above technical problems.
[0008] In order to achieve the above purpose, the utility model provides the following technical solutions:
[0009] A novel pressure swing adsorption treatment equipment for oilfield wellhead gas, comprising a filter device, a liquid-gas separator, an alkali washing tank, a methane purification recovery device and a compressor connected in sequence, wherein the methane purification recovery device comprises an adsorption tower 1 and an adsorption tower 2, wherein the upper end of the adsorption tower 1 is connected to the adsorption tower 2 through a pipeline, and the lower end of the adsorption tower 2 is connected to the adsorption tower 1 through a pipeline, i.e., a circulation is formed between the adsorption tower 1 and the adsorption tower 2;
[0010] The adsorption tower 1 and the adsorption tower 2 have the same structure and both include a tower body. The upper end of the tower body is connected to a methane exhaust pipe, which is connected to a compressor; the lower end of the tower body is connected to a nitrogen exhaust pipe, which is connected to a vacuum pump.
[0011] Preferably, an upper pressure equalizing valve is provided on the pipeline between the upper end of the adsorption tower 1 and the adsorption tower 2, and a lower pressure equalizing valve is provided on the pipeline between the lower end of the adsorption tower 2 and the adsorption tower 1.
[0012] Preferably, the methane exhaust pipe is provided with a methane exhaust valve, and the nitrogen exhaust pipe is provided with a nitrogen exhaust valve.
[0013] Preferably, an air inlet is provided at the bottom of the tower body, a mineral screen pipe is provided at the inner bottom of the tower body, and an adsorbent is filled at the top of the mineral screen pipe.
[0014] Preferably, the number of the methane purification recovery devices is at least one group.
[0015] Compared with the prior art, the utility model has the following beneficial effects: when the utility model is in use, the raw gas recovered from the wellhead enters the filtering device, and impurities such as mud, grease and so on are removed by separating solid particles; then the filtered gas is sent to the liquid-gas separator, and part of the water and oil remain at this time due to the expansion effect and the impact effect, and the unfiltered water and oil are separated from the gas, and the water, oil, dust and the like are removed through pretreatment; at this time, the pretreated gas is introduced into the alkaline washing tank, and the acidic gas (H2S, SO2, CO2) in the air itself or reacting with water is subjected to acid-base neutralization treatment; then the clean gas is introduced into the methane purification recovery device, and the nitrogen is adsorbed by the adsorbent and separated from the methane, and the vacuum pump extracts the nitrogen in the adsorbent, and the desorbed methane product gas is pressurized by the compressor and then transported to the pipeline network. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present utility model. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.
[0017] Figure 1 It is a schematic diagram of the overall structure of the utility model;
[0018] Figure 2 This is a schematic diagram of the structure of the methane purification recovery device of the present utility model.
[0019] Description of reference numerals:
[0020] 1-filter device, 2-liquid-gas separator, 3-alkali washing tank, 4-methane purification recovery device, 41-adsorption tower 1, 42-adsorption tower 2, 5-compressor, 6-methane exhaust pipe, 7-nitrogen exhaust pipe, 8-vacuum pump, 9-upper equalizing pressure valve, 10-lower equalizing pressure valve, 11-methane exhaust valve, 12-nitrogen exhaust valve. DETAILED DESCRIPTION
[0021] The following is a detailed description of the invention of the utility model by way of examples in conjunction with the accompanying drawings of the specification. Obviously, the described embodiments are only a part of the embodiments of the utility model, rather than all the embodiments. Example
[0022] like Figure 1 to Figure 2 As shown, the utility model discloses a novel pressure swing adsorption processing equipment for oilfield wellhead gas, comprising a filter device 1, a liquid-gas separator 2, an alkali washing tank 3, a methane purification recovery device 4 and a compressor 5 which are connected in sequence. In this embodiment, the number of methane purification recovery devices 4 is two groups, which is convenient for improving the processing efficiency; the methane purification recovery device 4 comprises an adsorption tower 1 41 and an adsorption tower 2 42, the upper end of the adsorption tower 1 41 is connected to the adsorption tower 2 42 through a pipeline, and the lower end of the adsorption tower 2 42 is connected to the adsorption tower 1 41 through a pipeline, that is, a circulation is formed between the adsorption tower 1 41 and the adsorption tower 2 42;
[0023] The adsorption tower 1 41 and the adsorption tower 2 42 have the same structure and both include a tower body. The upper end of the tower body is connected to a methane exhaust pipe 6, and a methane exhaust valve 11 is provided on the methane exhaust pipe 6. The methane exhaust pipe 6 is connected to a compressor 5; the lower end of the tower body is connected to a nitrogen exhaust pipe 7, and a nitrogen exhaust valve 12 is provided on the nitrogen exhaust pipe 7. A vacuum pump 8 is connected to the nitrogen exhaust pipe 7; an air inlet is provided at the bottom of the tower body, and a mineral sieve tube is provided at the bottom of the tower body. The top of the mineral sieve tube is filled with an adsorbent. In this embodiment, a molecular sieve is used as the adsorbent.
[0024] An upper pressure equalizing valve 9 is provided on the pipeline between the upper end of the adsorption tower 1 41 and the adsorption tower 2 42, and a lower pressure equalizing valve 10 is provided on the pipeline between the lower end of the adsorption tower 2 42 and the adsorption tower 1 41. By arranging the upper pressure equalizing valve 9 and the lower pressure equalizing valve 10, the pressures of the two towers are balanced, which can reduce the impact of the molecular sieve in the adsorption tower during switching on the one hand, and improve the recovery rate of methane on the other hand.
[0025] Purification principle: After the treated raw gas enters the adsorption tower 41, the molecular sieve adsorbs nitrogen, and the separated methane enters the compressor 5 through the methane exhaust pipe 6. At this time, the upper equalizing valve 9 is opened and the lower equalizing valve 10 is closed. A small amount of untreated raw gas in the adsorption tower 41 enters the adsorption tower 42. At the same time, the raw gas after external treatment is introduced into the adsorption tower 42, and the molecular sieve adsorbs nitrogen. The separated methane enters the compressor 5 through the methane exhaust pipe 6 on the adsorption tower 42. At this time, the upper equalizing valve 9 is closed and the lower equalizing valve 10 is opened. A small amount of untreated raw gas in the adsorption tower 42 enters the adsorption tower 41, and then the raw gas is introduced into the adsorption tower 41 for separation and purification. This operation is repeated in a cycle, and the nitrogen in the adsorption tower 41 and the adsorption tower 42 is extracted by the vacuum pump 8.
[0026] When the equipment is in use, the raw gas recovered from the wellhead enters the filtering device 1, and impurities such as mud, grease, etc. are removed by separating solid particles; then the filtered gas is sent to the liquid-gas separator 2, and some water and oil remain at this time due to the expansion effect and impact effect, and the unfiltered water and oil are separated from the gas, and the water, oil, dust, etc. are removed through pretreatment; at this time, the pretreated gas is introduced into the alkali washing tank 3, and the acidic gas (H2S, SO2, CO2) in the air itself or reacting with water is subjected to acid-base neutralization treatment; then the clean gas is introduced into the methane purification recovery device 4, and the adsorbent adsorbs nitrogen and separates it from methane, and the vacuum pump 8 extracts the nitrogen in the adsorbent, and the desorbed methane product gas is pressurized by the compressor 5 and then transported to the pipeline network.
[0027] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent substitutions or changes within the technical scope disclosed by the present invention according to the technical solution and application concept of the present invention, which should be covered by the protection scope of the present invention.
Claims
1. A novel pressure swing adsorption treatment equipment for oilfield wellhead gas, comprising a filter device (1), a liquid-gas separator (2), an alkali washing tank (3), a methane purification recovery device (4) and a compressor (5) connected in sequence, characterized in that: The methane purification recovery device (4) comprises an adsorption tower 1 (41) and an adsorption tower 2 (42), wherein the upper end of the adsorption tower 1 (41) is connected to the adsorption tower 2 (42) via a pipeline, and the lower end of the adsorption tower 2 (42) is connected to the adsorption tower 1 (41) via a pipeline, i.e., a circulation is formed between the adsorption tower 1 (41) and the adsorption tower 2 (42); The adsorption tower 1 (41) and the adsorption tower 2 (42) have the same structure and both comprise a tower body, the upper end of the tower body being connected to a methane exhaust pipe (6), the methane exhaust pipe (6) being in communication with a compressor (5); the lower end of the tower body being connected to a nitrogen exhaust pipe (7), the nitrogen exhaust pipe (7) being connected to a vacuum pump (8).
2. A novel pressure swing adsorption treatment equipment for oilfield wellhead gas as claimed in claim 1, characterized in that: An upper pressure equalizing valve (9) is provided on the pipeline between the upper end of the adsorption tower 1 (41) and the adsorption tower 2 (42), and a lower pressure equalizing valve (10) is provided on the pipeline between the lower end of the adsorption tower 2 (42) and the adsorption tower 1 (41).
3. A novel pressure swing adsorption treatment equipment for oilfield wellhead gas as claimed in claim 1, characterized in that: The methane exhaust pipe (6) is provided with a methane exhaust valve (11), and the nitrogen exhaust pipe (7) is provided with a nitrogen exhaust valve (12).
4. A novel pressure swing adsorption treatment equipment for oilfield wellhead gas as claimed in claim 1, characterized in that: An air inlet is arranged at the bottom of the tower body, a mineral screen pipe is arranged at the bottom of the tower body, and an adsorbent is filled at the top of the mineral screen pipe.
5. A novel pressure swing adsorption treatment equipment for oilfield wellhead gas as claimed in claim 1, characterized in that: The number of the methane purification recovery devices (4) is at least one group.