Skid-mounted equipment for purifying marsh gas by using water washing method

Abstract

The utility model relates to skid-mounted equipment for purifying marsh gas by using a water washing method, which comprises a first absorption tower, a second absorption tower and a desorption tower, the first absorption tower, the second absorption tower and the desorption tower respectively comprise a tower body, a packing layer and a spray head, and a raw material gas conveying pipe is arranged on the tower body in the first absorption tower; a middle gas conveying pipe is arranged in the first absorption tower and the second absorption tower, a crude methane conveying pipe is arranged on the tower top of a tower body of the second absorption tower, a resolver is arranged on the desorption tower, and the resolver comprises a shell, a connecting frame, an outer cylinder, an inner cylinder and a connecting ring; a first absorption liquid conveying pipe is arranged on the first absorption tower and the second absorption tower, the first absorption liquid conveying pipe is communicated with the shell, a second absorption liquid conveying pipe is arranged on the shell and the nozzle of the desorption tower, and a return gas conveying pipe is arranged on the shell above the connecting ring and the raw material gas conveying pipe. Methane desorbed in the absorption liquid is used as part of raw material gas for decarburization treatment. The utility model has the advantages of convenient use and wide market prospect.

Description

Technical Field

[0001] The utility model relates to biogas purification equipment using a water washing method, in particular to a skid-mounted equipment for purifying biogas using a water washing method. Background Art

[0002] Small and medium-sized biogas projects source fermentation feedstock from village and town waste and livestock manure. These projects face challenges such as regional dispersion, large volumes, difficulty in overall planning, high purification and refining costs, and low efficiency. The biogas produced is mostly used for low-value applications such as cooking, lighting, and power generation, far from achieving high-value utilization. Therefore, with economic development and advancements in science and technology, there is an urgent need for research and application of purification and refining systems for small and medium-sized biogas projects, demonstrating significant market potential. Skid-mounted systems integrate functional components onto a single, integrated base, allowing for complete installation and mobility. Using skid-mounted biogas purification equipment for purifying biogas produced by small and medium-sized biogas projects offers a natural advantage due to its ease of installation.

[0003] Biogas purification processes include desulfurization, decarbonization, and dehydration. Among these, high-pressure water scrubbing is a relatively mature method for decarbonization. The decarbonization process utilizes the principle that water, as an adsorption liquid, can adsorb large amounts of carbon dioxide and small amounts of methane under high pressure. Methane can be desorbed from the adsorption liquid under reduced pressure, and carbon dioxide can be desorbed from the adsorption liquid under heated conditions. Water is then recycled as the absorption liquid to decarbonize the desulfurized biogas. The solubility of methane in water is affected by temperature and pressure. Generally, its solubility decreases with increasing temperature and increases with increasing pressure. However, due to the small amount of methane dissolved in water under high pressure, this small amount of methane desorbs along with the large amount of carbon dioxide during the desorption process, forming exhaust gas. Although the proportion of carbon dioxide in this exhaust gas is high and the proportion of methane is low, the methane content is not within the explosion limit of methane. Therefore, direct discharge does not pose a safety risk, but methane is still wasted. In comparison, during the decarbonization process, carbon dioxide dissolves more readily in water due to its physical properties. Therefore, there is room for improvement in the existing biogas decarbonization process, allowing the adsorbed substances in the water used as the absorption liquid to be separated into recovered gas and discharged gas in a step-by-step manner. The recovered gas containing a large amount of methane is remixed with the process gas to be decarbonized after the desulfurization process to complete the decarbonization process. The gas containing a small amount of methane is used as the discharged gas, thereby reducing the methane content in the tail gas. This simplifies the tail gas treatment process and improves the methane extraction rate in the feed gas, thereby increasing the market competitiveness of the corresponding equipment. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the utility model provides a skid-mounted device for purifying biogas using a water washing method, which can use the methane analyzed in the absorption liquid as part of the raw gas for decarbonization, so as to overcome the defects of the existing technology.

[0005] The technical solution adopted by the utility model is: a skid-mounted equipment for purifying biogas by water washing method, comprising a first absorption tower, a second absorption tower and a desorption tower, wherein the first absorption tower, the second absorption tower and the desorption tower all comprise a tower body, a packing layer arranged in the tower body and a nozzle arranged on the tower body above the packing layer, a raw gas delivery pipe is arranged on the tower body below the packing layer in the first absorption tower, the tower top of the tower body of the first absorption tower and the tower body below the packing layer in the second absorption tower are connected through an intermediate gas delivery pipe, and a crude methane delivery pipe is arranged on the tower top of the tower body of the second absorption tower. A parser is provided on the top of the tower body of the analysis tower, and the parser includes a shell, a connecting frame arranged in the shell, an outer cylinder arranged on the connecting frame, an inner cylinder arranged in the inner cavity of the outer cylinder, and the inner cylinder above the outer cylinder and a connecting ring arranged on the shell; a first absorption liquid delivery pipe is provided on the bottom of the tower body of the first absorption tower and the bottom of the tower body of the second absorption tower, the first absorption liquid delivery pipe is connected to the shell outside the inner cylinder, the shell below the connecting frame and the nozzle of the analysis tower are connected through the second absorption liquid delivery pipe, and the shell above the connecting ring and the raw gas delivery pipe are connected through the reflux gas delivery pipe.

[0006] Preferably, the raw gas delivery pipe is provided with a first regulating valve, a buffer tank, a first compressor unit and an air mixer in sequence along the direction from close to the first absorption tower to away from the first absorption tower, the top of the buffer tank is provided with a pressure relief valve and a first pressure sensor, the air mixer includes a tank body and an air guide branch pipe, an air guide cone and a spiral blade arranged in sequence from the inlet end to the outlet end of the tank body, the tank body is installed on the raw gas delivery pipe, the air guide branch pipe is connected to the return gas delivery pipe, and the return gas delivery pipe is provided with a second regulating valve and a second pressure sensor in sequence along the direction from close to the air guide branch pipe to away from the air guide branch pipe.

[0007] Preferably, the bottom of the tower body of the first absorption tower and the first absorption liquid delivery pipe, as well as the first absorption liquid delivery pipe and the bottom of the tower body of the second absorption tower are respectively connected through absorption liquid delivery branches, and each absorption liquid delivery branch and the second absorption liquid delivery pipe are respectively provided with a third regulating valve, and the intermediate gas delivery pipe is sequentially provided with a one-way valve and a third pressure sensor along the direction from the first absorption tower to the second absorption tower.

[0008] Preferably, an exhaust gas delivery pipe is provided on the tower body above the nozzle of the analysis tower, and the exhaust gas delivery pipe is provided with a fourth pressure sensor and a vacuum pump in sequence along the direction from close to the analysis tower to away from the analysis tower; an air delivery pipe is provided on the tower body below the packing layer of the analysis tower, and the air delivery pipe is provided with a second compressor unit and an air filter in sequence along the direction from close to the analysis tower to away from the analysis tower.

[0009] Preferably, the inlet end of the third absorption liquid delivery pipe is provided on the bottom of the tower body of the analysis tower, and the third absorption liquid delivery pipe is provided with a first booster pump. The third absorption liquid delivery pipe between the first booster pump and the inlet end of the third absorption liquid delivery pipe is connected to the bottom of the tower body of the analysis tower via a fourth absorption liquid delivery pipe. The fourth absorption liquid delivery pipe is sequentially provided with a second booster pump, a fourth regulating valve and a chiller along the direction from the third absorption liquid delivery pipe to the tower body of the analysis tower. The outlet end of the third absorption liquid delivery pipe and the nozzle of the first absorption tower, as well as the nozzle of the second absorption tower and the outlet end of the third absorption liquid delivery pipe are respectively connected via a fifth absorption liquid delivery pipe, and each fifth absorption liquid delivery pipe is respectively provided with a fifth regulating valve.

[0010] Preferably, it also includes a molecular sieve adsorption tank and a refined methane delivery pipe. The number of the molecular sieve adsorption tanks is several, and the inlet end of each molecular sieve adsorption tank and the crude methane delivery pipe are respectively provided with a first delivery pipe, the outlet end of each molecular sieve adsorption tank and the refined methane delivery pipe are respectively provided with a second delivery pipe, and the crude methane delivery pipe and the refined methane delivery pipe are respectively provided with a first online chromatograph.

[0011] Preferably, a nitrogen delivery pipe and a nitrogen discharge pipe are further included, a third delivery pipe is respectively provided on the outlet end of each molecular sieve adsorption tank and the nitrogen delivery pipe, a fourth delivery pipe is respectively provided on the inlet end of each molecular sieve adsorption tank and the nitrogen discharge pipe, a second online chromatograph is provided on the nitrogen discharge pipe, and a nitrogen heater, a sixth regulating valve and a third compressor unit are sequentially provided on the nitrogen delivery pipe in a direction from close to the third delivery pipe to away from the third delivery pipe; a stop valve is respectively provided on each first delivery pipe, each second delivery pipe, each third delivery pipe and each fourth delivery pipe.

[0012] The beneficial effects of the utility model are as follows: first, the utility model transports the adsorption liquid adsorbed with carbon dioxide and methane into the parser and reduces the pressure above the liquid layer in the parser, thereby allowing the methane in the adsorption liquid to be parsed, greatly reducing the methane content in the adsorption liquid transported to the parsing tower, thereby reducing the amount of methane contained in the tail gas transported outward through the parsing tower, thereby improving the methane extraction rate in the desulfurized biogas transported upstream and received by the raw gas transmission pipe, and reducing the amount of methane contained in the tail gas transported outward through the parsing tower.

[0013] Secondly, the return gas delivery pipe of the present invention is sequentially provided with a second regulating valve and a second pressure sensor along the direction from close to the air guide branch to far away from the air guide branch. The installation of the second pressure sensor facilitates feedback of pressure parameters.

[0014] Again, the intermediate gas conveying pipe of the present invention is provided with a one-way valve and a third pressure sensor in sequence along the direction from the first absorption tower to the second absorption tower; the installation of the third pressure sensor facilitates the feedback of pressure parameters.

[0015] The utility model has the advantages of simple structure, convenient operation, ingenious design, greatly improved work efficiency, good social and economic benefits, and is a product that is easy to promote and use. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural diagram of the present utility model.

[0017] Figure 2 for Figure 1 A partially enlarged schematic diagram of detail A.

[0018] Figure 3 for Figure 1 A partially enlarged schematic diagram of detail B. DETAILED DESCRIPTION

[0019] like Figures 1 to 3As shown, a skid-mounted device for purifying biogas using a water washing method includes a first absorption tower, a second absorption tower and a desorption tower. The first absorption tower, the second absorption tower and the desorption tower all include a tower body 1, a packing layer 2 arranged in the tower body 1 and a nozzle 3 arranged on the tower body 1 above the packing layer 2. A raw gas conveying pipe 4 is arranged on the tower body 1 below the packing layer 2 in the first absorption tower. The top of the tower body 1 of the first absorption tower and the tower body 1 below the packing layer 2 in the second absorption tower are connected through an intermediate gas conveying pipe 5. A crude methane conveying pipe 6 is arranged on the top of the tower body 1 of the second absorption tower. The parser includes a shell 7, a connecting frame 8 arranged in the shell 7, an outer cylinder 9 arranged on the connecting frame 8, an inner cylinder 10 arranged in the inner cavity of the outer cylinder 9, and the inner cylinder 10 above the outer cylinder 9 and a connecting ring 11 arranged on the shell 7; a first absorption liquid delivery pipe 12 is provided on the bottom of the tower body 1 of the first absorption tower and the bottom of the tower body 1 of the second absorption tower, the first absorption liquid delivery pipe 12 is connected to the shell 7 outside the inner cylinder 10, the shell 7 below the connecting frame 8 and the nozzle 3 of the parsing tower are connected through the second absorption liquid delivery pipe 13, and the shell 7 above the connecting ring 11 and the raw gas delivery pipe 4 are connected through the reflux gas delivery pipe 14.

[0020] The raw gas delivery pipe 4 is provided with a first regulating valve 15, a buffer tank 16, a first compressor unit 17 and an air mixer in sequence along the direction from close to the first absorption tower to away from the first absorption tower. The top of the buffer tank 16 is provided with a pressure relief valve 18 and a first pressure sensor 19. The air mixer includes a tank body 20 and an air guide branch pipe 21, an air guide cone 22 and a spiral blade 23 arranged in sequence along the inlet end of the tank body 20 to the outlet end of the tank body 20. The air guide branch pipe 21 is located at the central axis of one end of the inner side of the tank body 20, and the central axis of the air guide cone 22 and the central axis of the tank body 20 are located on the same axis. Axis; the number of spiral blades 23 is several, and the several spiral blades 23 are evenly distributed in a star shape on the outside of the central axis of the tank body 20; the tank body 20 is installed on the raw gas delivery pipe 4, and the air guide branch pipe 21 is connected to the return gas delivery pipe 14, and the installation of the air mixer is convenient for mixing the recovered gas delivered from the return gas delivery pipe 14 and the desulfurized raw gas delivered through the raw gas delivery pipe 4; further, the return gas delivery pipe 14 is sequentially provided with a second regulating valve 24 and a second pressure sensor 25 along the direction from close to the air guide branch pipe 21 to away from the air guide branch pipe 21.

[0021] The bottom of the tower body 1 of the first absorption tower and the first absorption liquid delivery pipe 12, as well as the first absorption liquid delivery pipe 12 and the bottom of the tower body 1 of the second absorption tower, are each connected via an absorption liquid delivery branch pipe 26. Each absorption liquid delivery branch pipe 26 and the second absorption liquid delivery pipe 13 are each provided with a third regulating valve 27. The intermediate gas delivery pipe 5 is sequentially provided with a one-way valve 28 and a third pressure sensor 29 along the direction from the first absorption tower to the second absorption tower. Liquid level sensors 30 are each provided at the bottom of the tower body 1 of the first absorption tower, the bottom of the tower body 1 of the second absorption tower, the shell 7, and the bottom of the tower body 1 of the desorption tower; the installation of the liquid level sensor 30 facilitates feedback of liquid level parameters.

[0022] An exhaust gas delivery pipe 31 is provided on the tower body 1 above the nozzle 3 of the analysis tower, and the exhaust gas delivery pipe 31 is sequentially provided with a fourth pressure sensor 32 and a vacuum pump 33 along the direction from close to the analysis tower to away from the analysis tower; the installation of the vacuum pump 33 facilitates the reduction of the pressure of the tower body 1 above the packing layer 2 of the analysis tower, thereby facilitating the decomposition of carbon dioxide from the adsorption liquid entering the analysis tower; an air delivery pipe 34 is provided on the tower body 1 below the packing layer 2 of the analysis tower, and the air delivery pipe 34 is sequentially provided with a second compressor unit 35 and an air filter 36 along the direction from close to the analysis tower to away from the analysis tower.

[0023] The inlet end of the third absorption liquid delivery pipe 37 is provided at the bottom of the tower body 1 of the analysis tower, and the third absorption liquid delivery pipe 37 is provided with a first booster pump 38. The third absorption liquid delivery pipe 37 between the first booster pump 38 and the inlet end of the third absorption liquid delivery pipe 37 is connected to the bottom of the tower body 1 of the analysis tower by a fourth absorption liquid delivery pipe 39. The fourth absorption liquid delivery pipe 39 is sequentially provided with a second booster pump 41, a fourth regulating valve 40 and a chiller 42 along the direction from the third absorption liquid delivery pipe 37 to the tower body 1 of the analysis tower. The outlet end of the third absorption liquid delivery pipe 37 and the nozzle 3 of the first absorption tower, as well as the nozzle 3 of the second absorption tower and the outlet end of the third absorption liquid delivery pipe 37 are respectively connected through a fifth absorption liquid delivery pipe 43, and each fifth absorption liquid delivery pipe 43 is respectively provided with a fifth regulating valve 44.

[0024] In order to dehydrate the medium transported by the crude methane delivery pipe 6, this product also includes a molecular sieve adsorption tank 45 and a refined methane delivery pipe 46. The number of the molecular sieve adsorption tanks 45 is several. The inlet end of each molecular sieve adsorption tank 45 and the crude methane delivery pipe 6 are respectively provided with a first delivery pipe 47, and the outlet end of each molecular sieve adsorption tank 45 and the refined methane delivery pipe 46 are respectively provided with a second delivery pipe 48. The crude methane delivery pipe 6 and the refined methane delivery pipe 46 are respectively provided with a first online chromatograph 49. The crude methane delivery pipe 6 is provided with a seventh regulating valve 59; in addition, in order to realize the analysis of the molecular sieve adsorption tank 45, this product also includes a nitrogen delivery pipe 50 and a nitrogen discharge pipe 51. The outlet end of each molecular sieve adsorption tank 45 and the nitrogen delivery pipe 50 are respectively provided with a third delivery pipe 52, and the inlet end of each molecular sieve adsorption tank 45 and the nitrogen discharge pipe 51 are respectively provided with a fourth delivery pipe 53, and the nitrogen discharge pipe 51 is provided with a second online chromatograph 54. The nitrogen delivery pipe 50 is provided with a nitrogen heater 55, a sixth regulating valve 56 and a third compressor unit 57 in sequence along the direction from close to the third delivery pipe 52 to away from the third delivery pipe 52; each first delivery pipe 47, each second delivery pipe 48, each third delivery pipe 52 and each fourth delivery pipe 53 are respectively provided with a stop valve 58.

[0025] The method of using this product is as follows: Figures 1 to 3 As shown, the following steps are included:

[0026] S1. The desulfurized biogas transported from upstream is transported to the raw gas delivery pipe 4. The desulfurized biogas enters the air mixer in the raw gas delivery pipe 4 and is mixed with the recovered gas transported to the air mixer through the reflux gas delivery pipe 14 to form the raw gas, which is discharged from the air mixer and continues to move along the raw gas delivery pipe 4. After being compressed by the first compressor unit 17, it is transported to the buffer tank 16 and then transported to the first absorption tower through the first regulating valve 15.

[0027] S2. After the raw gas enters the first absorption tower, it forms a first rising airflow. The nozzle 3 of the first absorption tower receives the first absorption liquid and transports it into the first absorption tower. After the first absorption liquid enters the first absorption tower, it forms a first descending liquid flow. The first rising airflow and the first descending liquid flow complete full contact in the packing layer 2 of the first absorption tower. A large amount of carbon dioxide and a small amount of methane in the first rising airflow are dissolved in the first descending liquid flow. The first descending liquid flow continues to descend and forms a first absorption liquid temporary storage area at the bottom of the tower body 1 of the first absorption tower; the first rising airflow continues to ascend and forms an intermediate gas and is transported to the second absorption tower through the intermediate gas conveying pipe 5.

[0028] S3. The intermediate gas forms a second rising airflow after entering the second absorption tower. The nozzle 3 of the second absorption tower receives the second absorption liquid and transports it into the second absorption tower. The second absorption liquid forms a second descending liquid flow after entering the second absorption tower. The second rising airflow and the second descending liquid flow complete full contact in the packing layer 2 of the second absorption tower. The remaining carbon dioxide in the second rising airflow is dissolved in the second descending liquid flow. The second descending liquid flow continues to descend and forms a second absorption liquid temporary storage area at the bottom of the tower body 1 of the second absorption tower; the second rising airflow forms decarbonized biogas and is transported to the molecular sieve adsorption tank 45 in working state through the crude methane conveying pipe 6 for dehydration and removal of trace carbon dioxide; the biogas with dehydration and trace carbon dioxide removed forms refined biogas and is transported to downstream equipment through the refined methane conveying pipe 46.

[0029] During step S2 and step S3, the first absorption liquid temporary storage area and the second absorption liquid temporary storage area jointly transport liquid medium to the first absorption liquid delivery pipe 12 and form a desorption liquid flow in the first absorption liquid delivery pipe 12. The desorption liquid flow is transported to the cavity between the shell 7 and the outer tube 9 through the first absorption liquid delivery pipe 12. After adjusting the opening of the second regulating valve 24, the pressure above the liquid layer of the shell 7 drops, and a large amount of methane and a small amount of carbon dioxide are desorbed to form recovery gas. The recovery gas first ascends along the cavity between the shell 7 and the outer tube 9, and enters the cavity between the outer tube 9 and the inner tube 10 under the obstruction of the connecting ring 11 to form the first recovery gas deflection and complete gas-liquid separation. After completing the gas-liquid separation, the recovery gas completes the second recovery gas deflection through the inner cavity of the inner tube 10 and is transported to the reflux gas delivery pipe 14 through the top of the shell 7. The recovery gas is transported to the air mixer through the reflux gas delivery pipe 14.

[0030] The liquid at the bottom of the shell 7 is transported to the analysis tower through the second absorption liquid delivery pipe 13 to form a third descending liquid flow. During this period, the liquid level sensor 30 installed on the shell 7 should be maintained within the preset liquid level range; at the same time, the analysis tower receives pressurized air after the mechanical impurities are removed by the air filter 36 and the second compressor unit 35 is pressurized. After the pressurized air enters the analysis tower, a third rising airflow is formed. The third rising airflow and the third descending liquid flow are fully contacted in the packing layer 2 of the analysis tower and complete countercurrent heat exchange. A large amount of carbon dioxide and a trace amount of methane in the third descending liquid flow are analyzed from the third descending liquid flow, merged in the third rising airflow, and continue to rise and are transported to the exhaust gas treatment equipment through the exhaust gas delivery pipe 31.

[0031] The third descending liquid flow continues to descend and forms a third absorption liquid temporary storage area at the bottom of the tower body 1 of the analysis tower. The third absorption liquid temporary storage area continuously transports absorption liquid outward through the third absorption liquid delivery pipe 37. The absorption liquid is divided into three parts in the third absorption liquid delivery pipe 37, namely, the first absorption liquid, the second absorption liquid and the cooling liquid. The first absorption liquid is transported to the nozzle 3 of the first absorption tower through the corresponding fourth absorption liquid delivery pipe 39, thereby continuously providing the first descending liquid flow in the first absorption tower; the first absorption liquid is transported to the nozzle 3 of the second absorption tower through the corresponding fourth absorption liquid delivery pipe 39, thereby continuously providing the second descending liquid flow in the second absorption tower; the cooling liquid is transported to the fourth absorption liquid delivery pipe 39, pressurized by the second booster pump 41, and then cooled by the chiller 42 to adjust the temperature of the third absorption liquid temporary storage area and thus adjust the temperature of the first absorption liquid and the temperature of the second absorption liquid.

[0032] During step S3, when the molecular sieve adsorption tank 45 in use reaches its use cycle or the first online chromatograph 49 installed on the refined methane delivery pipe 46 has an abnormality, the use status of several molecular sieve adsorption tanks 45 should be switched in time, that is, a molecular sieve adsorption tank 45 that was originally in the standby state is connected to the air flow through the refined methane delivery pipe 46 and the crude methane delivery pipe 6 for adsorption, and then the molecular sieve adsorption tank 45 that was originally in use is disconnected from the refined methane delivery pipe 46 and the crude methane delivery pipe 6. After completing the above operation, the molecular sieve adsorption tank 45 that was originally in use is now a molecular sieve adsorption tank 45 in a waiting state, and the molecular sieve adsorption tank 45 that was newly connected between the refined methane delivery pipe 46 and the crude methane delivery pipe 6 is now in use. The molecular sieve adsorption tank 45 that is now in a waiting state needs to be analyzed before it can be converted back to a molecular sieve adsorption tank 45 in a standby state, which specifically includes the following steps:

[0033] The nitrogen delivery pipe 50 receives the nitrogen delivered from the upstream and is compressed by the third compressor unit 57 and then heated by the nitrogen heater 55 to form a first heated airflow. The first heated airflow enters the molecular sieve adsorption tank 45 from the outlet end of the molecular sieve adsorption tank 45 in the state to be desorbed, and then continuously delivers the second heated airflow outward through the inlet end of the molecular sieve adsorption tank 45. During this process, the first heated airflow completes the desorption of carbon dioxide and water adsorbed in the molecular sieve adsorption tank 45. The desorbed water and carbon dioxide are merged into the first heated airflow to form the second heated airflow, which is delivered outward through the nitrogen discharge pipe 51 to the corresponding exhaust gas treatment equipment. When the parameters fed back by the second online chromatograph 54 reach the preset range, the molecular sieve adsorption tank 45 originally in the state to be analyzed is converted into the molecular sieve adsorption tank 45 in the standby state again.

[0034] Through this embodiment, it is achieved that the adsorption liquid adsorbed with carbon dioxide and methane is transported into the parser and the pressure above the liquid layer in the parser is reduced, so that the methane in the adsorption liquid is decomposed, which greatly reduces the methane content in the adsorption liquid transported to the parsing tower, thereby reducing the amount of methane contained in the tail gas transported out through the parsing tower, thereby improving the methane extraction rate in the desulfurized biogas transported upstream by the raw gas delivery pipe 4, and reducing the amount of methane contained in the tail gas transported out through the parsing tower.

[0035] The embodiments described above are only preferred embodiments of the present invention and do not limit the scope of implementation of the present invention. Therefore, any equivalent changes or modifications made based on the structure, features and principles described in the patent scope of the present invention should be included in the scope of the patent application of the present invention.

Claims

1. A skid-mounted device for purifying biogas using a water washing method, comprising a first absorption tower, a second absorption tower and a desorption tower, wherein the first absorption tower, the second absorption tower and the desorption tower each comprise a tower body (1), a packing layer (2) arranged in the tower body (1) and a nozzle (3) arranged on the tower body (1) above the packing layer (2), and characterized in that: A raw gas delivery pipe (4) is provided on the tower body (1) below the packing layer (2) in the first absorption tower. The top of the tower body (1) of the first absorption tower and the tower body (1) below the packing layer (2) in the second absorption tower are connected through an intermediate gas delivery pipe (5). A crude methane delivery pipe (6) is provided on the top of the tower body (1) of the second absorption tower. A parser is provided on the top of the tower body (1) of the parsing tower. The parser comprises a shell (7), a connecting frame (8) provided in the shell (7), an outer cylinder (9) provided on the connecting frame (8), and an inner cylinder provided in the inner cavity of the outer cylinder (9). (10) and an inner cylinder (10) above the outer cylinder (9) and a connecting ring (11) provided on the shell (7); a first absorption liquid delivery pipe (12) is provided on the bottom of the tower body (1) of the first absorption tower and the bottom of the tower body (1) of the second absorption tower, the first absorption liquid delivery pipe (12) is connected to the shell (7) outside the inner cylinder (10), the shell (7) below the connecting frame (8) and the nozzle (3) of the analysis tower are connected through the second absorption liquid delivery pipe (13), and the shell (7) above the connecting ring (11) and the raw gas delivery pipe (4) are connected through the reflux gas delivery pipe (14).

2. The skid-mounted equipment for biogas purification using a water washing method according to claim 1, characterized in that: The raw gas delivery pipe (4) is provided with a first regulating valve (15), a buffer tank (16), a first compressor unit (17) and an air mixer in sequence along the direction from close to the first absorption tower to far away from the first absorption tower. The top of the buffer tank (16) is provided with a pressure relief valve (18) and a first pressure sensor (19). The air mixer includes a tank body (20) and an air guide branch pipe (21), an air guide cone (22) and a spiral blade (23) arranged in sequence along the direction from the inlet end of the tank body (20) to the outlet end of the tank body (20). The tank body (20) is installed on the raw gas delivery pipe (4). The air guide branch pipe (21) is connected to the return gas delivery pipe (14). The return gas delivery pipe (14) is provided with a second regulating valve (24) and a second pressure sensor (25) in sequence along the direction from close to the air guide branch pipe (21) to far away from the air guide branch pipe (21).

3. The skid-mounted equipment for biogas purification using a water washing method according to claim 1, characterized in that: The bottom of the tower body (1) of the first absorption tower and the first absorption liquid delivery pipe (12), as well as the first absorption liquid delivery pipe (12) and the bottom of the tower body (1) of the second absorption tower, are respectively connected via absorption liquid delivery branch pipes (26). Each absorption liquid delivery branch pipe (26) and the second absorption liquid delivery pipe (13) are respectively provided with a third regulating valve (27). The intermediate gas delivery pipe (5) is sequentially provided with a one-way valve (28) and a third pressure sensor (29) along the direction from the first absorption tower to the second absorption tower.

4. The skid-mounted equipment for biogas purification using a water washing method according to claim 1, characterized in that: An exhaust gas delivery pipe (31) is provided on the tower body (1) above the nozzle (3) of the analysis tower, and a fourth pressure sensor (32) and a vacuum pump (33) are sequentially provided on the exhaust gas delivery pipe (31) along a direction from close to the analysis tower to away from the analysis tower; an air delivery pipe (34) is provided on the tower body (1) below the packing layer (2) of the analysis tower, and a second compressor unit (35) and an air filter (36) are sequentially provided on the air delivery pipe (34) along a direction from close to the analysis tower to away from the analysis tower.

5. The skid-mounted equipment for biogas purification using a water washing method according to claim 1, characterized in that: The inlet end of the third absorption liquid delivery pipe (37) is provided on the bottom of the tower body (1) of the analytical tower. The third absorption liquid delivery pipe (37) is provided with a first booster pump (38). The third absorption liquid delivery pipe (37) between the first booster pump (38) and the inlet end of the third absorption liquid delivery pipe (37) is connected to the bottom of the tower body (1) of the analytical tower. The fourth absorption liquid delivery pipe (39) is connected along the third absorption liquid delivery pipe (37) to the bottom of the analytical tower. A second booster pump (41), a fourth regulating valve (40) and a chiller (42) are sequentially provided in the tower body (1) of the analysis tower. The outlet end of the third absorption liquid delivery pipe (37) and the nozzle (3) of the first absorption tower, as well as the nozzle (3) of the second absorption tower and the outlet end of the third absorption liquid delivery pipe (37) are respectively connected through a fifth absorption liquid delivery pipe (43). Each fifth absorption liquid delivery pipe (43) is respectively provided with a fifth regulating valve (44).

6. The skid-mounted equipment for biogas purification using a water washing method according to claim 1, characterized in that: The invention also includes a molecular sieve adsorption tank (45) and a refined methane delivery pipe (46). The number of the molecular sieve adsorption tanks (45) is several. The inlet end of each molecular sieve adsorption tank (45) and the crude methane delivery pipe (6) are respectively provided with a first delivery pipe (47). The outlet end of each molecular sieve adsorption tank (45) and the refined methane delivery pipe (46) are respectively provided with a second delivery pipe (48). The crude methane delivery pipe (6) and the refined methane delivery pipe (46) are respectively provided with a first online chromatograph (49).

7. The skid-mounted equipment for biogas purification using a water washing method according to claim 6, characterized in that: The invention also includes a nitrogen delivery pipe (50) and a nitrogen discharge pipe (51), wherein the outlet end of each molecular sieve adsorption tank (45) and the nitrogen delivery pipe (50) are respectively provided with a third delivery pipe (52), the inlet end of each molecular sieve adsorption tank (45) and the nitrogen discharge pipe (51) are respectively provided with a fourth delivery pipe (53), the nitrogen discharge pipe (51) is provided with a second online chromatograph (54), and the nitrogen delivery pipe (50) is provided with a nitrogen heater (55), a sixth regulating valve (56) and a third compressor unit (57) in sequence along the direction from close to the third delivery pipe (52) to away from the third delivery pipe (52); and each first delivery pipe (47), each second delivery pipe (48), each third delivery pipe (52) and each fourth delivery pipe (53) are respectively provided with a stop valve (58).

Images