Biogas purification device

Abstract

The utility model provides a biogas purification device which comprises a crude biogas buffer tank, a biogas booster fan, a precooler I, a steam-water separator, a biogas compressor, a precooler II, a cryogenic condensed water separator, a preheater, a desulfurization mechanism, a filter II, a decarbonization mechanism and a product tank which are sequentially communicated, and an outlet of the product tank is communicated with a biogas pipeline; the top of the crude biogas buffer tank is provided with a crude biogas blow-down pipe, the bottom of the crude biogas buffer tank is communicated with a condensed water main pipe, and the steam-water separator and the cryogenic condensed water separator are both communicated with the condensed water main pipe. The device integrates biogas dehydration, desulfurization and decarburization, and is suitable for various application scenes of large-scale biogas projects. A physical separation principle is applied in the purification process, chemical reagents do not need to be additionally added, meanwhile, the content of main impurities in the purified and extracted biogas is detected through a gas analyzer, the concentration of the purified biogas can reach 98% or above, and the obtained methane product is high in purity.

Description

Technical Field

[0001] This utility model belongs to the field of biogas engineering technology, and specifically relates to a biogas purification and upgrading device. Background Technology

[0002] Biogas purification mainly involves removing H2S, H2O, CO2, and halogenated compounds from biogas. The purpose of purification is to prevent corrosion of equipment, etc. Biogas refining mainly involves removing CO2 from biogas. The purpose of refining is to increase the calorific value of biogas. Biogas purification and refining can achieve efficient utilization of biogas resources, enabling biogas to replace petrochemical fuels and be used as vehicle fuel, for decentralized residential gas supply, or directly connected to natural gas pipeline networks, etc.

[0003] Domestically, membrane purification and alkaline washing processes are the main technologies used. Membrane purification technology has very high requirements for the sulfur content in the biogas at the upstream end; it must be desulfurized to ≤10ppm before entering the membrane purification system. Desulfurization, dehydration, and decarbonization cannot be integrated into a single unit. Alkaline washing requires the consumption of alkali solution, producing harmful components. Pressure swing adsorption (PSA) is mainly used in large-scale chemical plants, and equipment applied to biogas projects is primarily imported. Utility Model Content

[0004] The purpose of this invention is to provide a biogas purification and upgrading device to overcome the above-mentioned technical problems existing in the prior art.

[0005] Therefore, the technical solution provided by this utility model is as follows:

[0006] A biogas purification and upgrading device includes a crude biogas buffer tank, a biogas booster fan, a precooler I, a gas-water separator, a biogas compressor, a precooler II, a deep cooling condensate separator, a preheater, a desulfurization mechanism, a filter II, a decarbonization mechanism, and a product tank connected in sequence. The outlet of the product tank is connected to a biogas pipeline.

[0007] The crude biogas buffer tank is equipped with a crude biogas vent pipe at the top, and a condensate main pipe is connected to the bottom of the crude biogas buffer tank. The steam-water separator and the deep condensate separator are both connected to the condensate main pipe.

[0008] A filter is provided between the deep cooling condensate separator and the preheater. The top of the coarse biogas buffer tank is connected to a substandard biogas return pipe. The other end of the substandard biogas return pipe is connected to the outlet of the biogas filter tank and the decarbonization mechanism, respectively.

[0009] The drain outlet of the precooler 2 and the inlet of the preheater are connected by a preheating water pipe.

[0010] It also includes a gas analyzer, the gas analyzer’s inlet of which is connected to the outlet of the biogas filter tank, the outlet of the decarbonization mechanism, and the biogas pipeline.

[0011] The decarbonization mechanism includes a pressure swing adsorption system and a vacuum pump group. The inlet end of the pressure swing adsorption system and filter two, and the outlet end are connected to the product tank through pipelines and product gas regulating valves. The pressure swing adsorption system and the vacuum pump group are connected. The pressure swing adsorption system is equipped with a carbon molecular sieve. The top of the product tank is equipped with a safety valve and a vent regulating valve.

[0012] The biogas compressors are two in number and connected in parallel, and each biogas compressor is connected to an overpressure vent pipe.

[0013] The desulfurization mechanism includes two desulfurization tanks, namely Desulfurization Tank 1 and Desulfurization Tank 2, which are connected in series.

[0014] The beneficial effects of this utility model are:

[0015] This utility model provides a biogas purification and upgrading device that integrates biogas dehydration, desulfurization, and decarbonization, making it suitable for various application scenarios in large-scale biogas projects. The purification and upgrading process utilizes physical separation principles, eliminating the need for external chemical reagents. The entire process generates almost no waste. Simultaneously, a gas analyzer is used to detect the content of major impurities in the purified biogas. The concentration of the purified biogas can reach over 98%, resulting in a high-purity methane product.

[0016] The purification and upgrading device separates oil, gas, and water through filter one. The desulfurized biogas is then filtered through filter two to remove dust, and the dry, clean biogas is sent into the pressure swing adsorption (PSA) system. Before entering the PSA system, regulating valve one is installed on the biogas main pipe and the biomethane main pipe after the PSA system for online analysis of methane, oxygen, moisture, and carbon dioxide in the biogas and biomethane during operation, ensuring the product gas meets quality standards. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of one embodiment of the present invention.

[0018] In the diagram: 1. Crude biogas inlet pipe; 2. Crude biogas buffer tank; 3. Crude biogas vent pipe; 4. Substandard biogas return pipe; 5. Biogas booster fan; 6. Precooler I; 7. Gas-water separator; 8. Biogas compressor; 9. Precooler II; 10. Overpressure vent pipe; 11. Deep cooling condensate separator; 12. Filter I; 13. Preheater; 14. Condensate main pipe; 15. Desulfurization tank I; 16. Desulfurization tank II; 17. Filter II; 18. Pressure swing adsorption system; 19. Vacuum pump set; 20. Product tank; 21. Safety valve; 22. Vent regulating valve; 23. Gas analyzer; 24. Biogas pipeline; 25. Biogas flow meter; 26. Biogas pipe; 27. Product gas regulating valve; 28. Product gas analysis pipe regulating valve I; 29. ​​Product gas analysis pipe regulating valve II; 30. Product gas analysis pipe regulating valve III. Detailed Implementation

[0019] The following specific embodiments illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification.

[0020] Exemplary embodiments of the present invention are now described with reference to the accompanying drawings. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided to fully and completely disclose the present invention and to fully convey its scope to those skilled in the art. The terminology used in the exemplary embodiments shown in the drawings is not intended to limit the present invention. In the drawings, the same units / elements are referred to by the same reference numerals.

[0021] Unless otherwise stated, the terms used herein (including technical terms) have their common meaning as understood by one of ordinary skill in the art. Furthermore, it is understood that terms defined in commonly used dictionaries should be understood to have a meaning consistent with the context of their relevant field, and not to be interpreted as having an idealized or overly formal meaning.

[0022] Example 1

[0023] This utility model provides a biogas purification and enhancement device, such as... Figure 1 As shown, the system includes, in sequence, a crude biogas buffer tank 2, a biogas booster fan 5, a precooler 1 6, a gas-water separator 7, a biogas compressor 8, a biogas precooler 2 9, a deep cooling condensate separator 11, a preheater 13, a desulfurization mechanism, a filter 2 17, a decarbonization mechanism, and a product tank 20. The outlet of the product tank 20 is connected to a biogas pipeline 24.

[0024] The top of the coarse biogas buffer tank 2 is provided with a coarse biogas vent pipe 3, and the bottom of the coarse biogas buffer tank 2 is connected to a condensate main pipe 14. The steam-water separator 7 and the deep condensate separator 11 are both connected to the condensate main pipe 14.

[0025] Work process:

[0026] 5~10kPa (G) crude biogas (methane content 45~70 Vol%, carbon dioxide content 30~55 Vol%, hydrogen sulfide content 100~1500ppm, saturated water) is sent into crude biogas buffer tank 2 through crude biogas inlet pipe 1. An online pressure gauge and an online thermometer are installed on the inlet pipe to test the inlet pressure and temperature in real time. After passing through the crude biogas buffer tank 2, the biogas is sent to the biogas booster blower 5, where it is initially pressurized to 50kPa~70kPa(G) and the temperature rises to 40~60℃. The pressurized crude biogas is then sent to the precooler 6, where it is cooled to about 25℃. The gas is then separated from the water by the gas-water separator 7 and discharged into the condensate main pipe 14 through a pipeline. The biogas with the water initially separated is then sent to the biogas compressor 8, where it is compressed to 0.7~1.3MPa(G) and the temperature rises to a maximum of 90℃. The biogas compressor 8 requires cooling water for heat dissipation during operation. The overpressurized gas is vented through the overpressure vent pipe 10.

[0027] The compressed biogas is fed into biogas precooler 29, where it is initially cooled to approximately 60-70°C using 32°C cooling water, and the cooling water temperature is raised to 40-45°C. After precooling, the crude biogas is sent to deep cooling condensate separator 11 for further cooling to approximately 10°C, almost completely removing the water from the biogas. The separated condensate is sent to the condensate main pipe 14 for centralized discharge. Subsequently, the biogas enters preheater 13 and is heated to 25°C. Then, the biogas is sent to desulfurization tank 15 and desulfurization tank 26 to remove hydrogen sulfide from the dry biogas, resulting in a sulfur content of ≤7ppm in the purified biogas. The desulfurized biogas is filtered through filter 2 17 to remove dust from the gas, and the dry and clean biogas is sent to pressure swing adsorption system 18. In the pressure swing adsorption system 18, methane and carbon dioxide are separated through batch-by-batch alternating filling and venting. The clean biogas after decarbonization is sent to product tank 20 for buffer storage.

[0028] Regulating valves are installed in the biogas main pipe before entering the pressure swing adsorption system 18 and the biomethane main pipe after entering the pressure swing adsorption system 18. These valves are used for online analysis of methane, oxygen, moisture and carbon dioxide in biogas and biomethane during operation to ensure that the product gas is qualified.

[0029] Example 2

[0030] Based on Example 1, this example provides a biogas purification and upgrading device. A filter is provided between the deep cooling condensate separator 11 and the preheater 13. The top of the coarse biogas buffer tank 2 is connected to a substandard biogas return pipe 4. The other end of the substandard biogas return pipe 4 is connected to the outlet of the biogas filter tank and the decarbonization mechanism, respectively.

[0031] like Figure 1As shown, after pre-cooling, the crude biogas is sent to the deep cooling condensate separator 11 for further cooling and dehydration, and then enters the filter 1 for oil-gas-water separation. The condensate containing trace amounts of oil is discharged to the condensate main pipe 14 through the pipeline.

[0032] Example 3

[0033] Based on Example 1, this example provides a biogas purification and upgrading device, wherein the drain outlet of the biogas precooler 2 9 and the inlet of the preheater 13 are connected by a preheating water pipe.

[0034] like Figure 1 As shown, cooling water enters the precooler 6 to initially cool the crude biogas to 60℃~70℃, and the cooling water temperature rises to 40~45℃. This part of the water enters the preheater 13 through the preheating water pipe to heat the biogas filtered by the filter to about 25℃.

[0035] Example 4

[0036] Based on Example 1, this example provides a biogas purification and upgrading device, which also includes a gas analyzer 23. The gas analyzer 23 has its inlet connected to the outlet of the biogas filter tank, the outlet of the decarbonization mechanism, and the biogas pipeline 24.

[0037] like Figure 1 As shown, a product gas analysis pipe regulating valve 28 is installed between the biogas filter tank and the gas analyzer 23. Opening the product gas analysis pipe regulating valve 28 allows for the analysis of the filtered biogas. A product gas analysis pipe regulating valve 29 is installed between the decarbonization mechanism and the gas analyzer 23. Opening the product gas analysis pipe regulating valve 29 allows for the analysis of the decarbonized biogas. A product gas analysis pipe regulating valve 30 is installed between the biogas pipeline 24 and the gas analyzer 23. Opening the product gas analysis pipe regulating valve 30 allows for online analysis of methane, oxygen, moisture, and carbon dioxide in the purified biogas to ensure the product gas is qualified.

[0038] The substandard biogas discharged from the biogas filter tank and decarbonization mechanism is returned to the coarse biogas buffer tank 2 through the substandard biogas return pipe 4. The outlet of the biogas filter tank can also be connected to the biogas boiler through the biogas pipe 26. By installing the biogas flow meter 25 and its matching valve group, the biogas boiler can be used for heating in the biogas project, realizing the high-value utilization of biogas.

[0039] Example 5

[0040] Based on Example 1, this example provides a biogas purification and upgrading device. The decarbonization mechanism includes a pressure swing adsorption system 18 and a vacuum pump group 19. The inlet end of the pressure swing adsorption system 18 is connected to a filter 17, and the outlet end is connected to a product tank 20 through a pipeline and a product gas regulating valve 27. The pressure swing adsorption system 18 is connected to the vacuum pump group 19. A carbon molecular sieve is provided inside the pressure swing adsorption system 18. A safety valve 21 and a vent regulating valve 22 are provided on the top of the product tank 20.

[0041] In the pressure swing adsorption system 18, biogas achieves the separation of methane and carbon dioxide through batch alternating filling and venting. During the pressurization process, carbon dioxide is adsorbed on the surface of the carbon molecular sieve. After absorption is completed, the regulating valve is opened to send out biogas. After the clean biogas is discharged, the regulating valve is closed, and the vacuum pump group 19 is turned on to release the carbon dioxide gas adsorbed by the carbon molecular sieve. After the gas is completely discharged, the vacuum group is turned off. Repeating the above operation can achieve continuous decarbonization of biogas.

[0042] Example 6

[0043] Based on Example 1, this example provides a biogas purification and upgrading device, wherein there are two biogas compressors 8 connected in parallel, and the biogas compressors 8 are connected to an overpressure venting pipe 10.

[0044] The biogas, after initial separation of moisture, is fed into the biogas compressor 8, which compresses the biogas to 0.7~1.3MPa(G) and raises the temperature to a maximum of 90℃. During operation, the biogas compressor 8 requires cooling water for heat dissipation. The overpressured gas is vented through the overpressure vent pipe 10.

[0045] Example 7

[0046] Based on Example 1, this example provides a biogas purification and upgrading device, wherein the desulfurization mechanism includes two desulfurization tanks 15 and 16 connected in series.

[0047] The biogas is sequentially fed into desulfurization tank 15 and desulfurization tank 26 to remove hydrogen sulfide from the dried biogas. The sulfur content in the purified biogas is ≤7ppm.

[0048] The above examples are merely illustrative of this utility model and do not constitute a limitation on the scope of protection of this utility model. All designs that are the same as or similar to this utility model are within the scope of protection of this utility model.

Claims

1. A biogas purification and upgrading device, characterized in that: It includes a crude biogas buffer tank, a biogas booster fan, a precooler I, a gas-water separator, a biogas compressor, a precooler II, a deep cooling condensate separator, a preheater, a desulfurization mechanism, a filter II, a decarbonization mechanism, and a product tank, connected in sequence. The outlet of the product tank is connected to a biogas pipeline. The crude biogas buffer tank is equipped with a crude biogas vent pipe at the top, and a condensate main pipe is connected to the bottom of the crude biogas buffer tank. The steam-water separator and the deep condensate separator are both connected to the condensate main pipe.

2. The biogas purification and upgrading device according to claim 1, characterized in that: A filter is provided between the deep cooling condensate separator and the preheater. The top of the coarse biogas buffer tank is connected to a substandard biogas return pipe. The other end of the substandard biogas return pipe is connected to the outlet of the biogas filter tank and the decarbonization mechanism, respectively.

3. The biogas purification and upgrading device according to claim 1, characterized in that: The drain outlet of the precooler 2 and the inlet of the preheater are connected by a preheating water pipe.

4. The biogas purification and upgrading device according to claim 1, characterized in that: It also includes a gas analyzer, the gas analyzer’s inlet of which is connected to the outlet of the biogas filter tank, the outlet of the decarbonization mechanism, and the biogas pipeline.

5. The biogas purification and upgrading device according to claim 1, characterized in that: The decarbonization mechanism includes a pressure swing adsorption system and a vacuum pump group. The inlet end of the pressure swing adsorption system and filter two, and the outlet end are connected to the product tank through pipelines and product gas regulating valves. The pressure swing adsorption system and the vacuum pump group are connected. The pressure swing adsorption system is equipped with a carbon molecular sieve. The top of the product tank is equipped with a safety valve and a vent regulating valve.

6. A biogas purification and upgrading device according to any one of claims 1-5, characterized in that: The biogas compressors are two in number and connected in parallel, and each biogas compressor is connected to an overpressure vent pipe.

7. A biogas purification and upgrading device according to any one of claims 1-5, characterized in that: The desulfurization mechanism includes two desulfurization tanks, namely Desulfurization Tank 1 and Desulfurization Tank 2, which are connected in series.

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