A system for realizing biogas residue resource and gas purification simultaneously

Abstract

This utility model relates to the field of organic waste treatment technology and discloses a system for simultaneously realizing the resource utilization of biogas residue and the purification of gas. The system includes a receiving hopper, an anaerobic digester, a solid-liquid separator, a material dispersing device, a drying furnace, a pyrolysis furnace, a gas storage tank, and a gas purification unit. The receiving hopper is connected to the feed end of the anaerobic digester via a conveying device. The discharge end of the anaerobic digester is connected to the feed end of the solid-liquid separator. The discharge ends of both the material dispersing device and the solid-liquid separator are connected to the feed end of the drying furnace. The discharge end of the drying furnace is connected to the feed end of the pyrolysis furnace. This utility model introduces tar-containing pyrolysis gas generated in the pyrolysis furnace into the anaerobic digester and uses biochar as an anaerobic microbial promoter to efficiently convert tar into methane within the digester. This not only completely eliminates the pollution risk of tar to the subsequent gas purification system but also significantly increases the total methane production.

Description

Technical Field

[0001] This utility model relates to the field of organic waste treatment technology, specifically a system that simultaneously realizes the resource utilization of biogas residue and the purification of gas. Background Technology

[0002] Organic solid waste refers to a type of solid waste containing organic matter generated during industrial, agricultural, and domestic production activities. Currently, the main methods for treating organic solid waste are biological methods and thermochemical methods.

[0003] However, the above-mentioned treatment methods still have the following problems in actual use: Anaerobic fermentation technology produces biogas, which is a clean energy source with relatively high energy quality, but it is lacking in volume reduction. Furthermore, anaerobic digestate, dry waste, industrial solid waste, and garden waste with low moisture content are difficult to biodegrade. Aerobic fermentation technology has relatively low treatment costs and can achieve waste reduction and resource recovery, but the treatment cycle is long and requires strict control of temperature, humidity, ventilation, and other conditions. Pyrolysis technology has a complex and costly process for purifying the pyrolysis gas containing tar. Incineration technology produces a large amount of heat and harmful gases, such as sulfur dioxide, nitrogen oxides, and dioxins, requiring advanced exhaust gas treatment equipment to reduce environmental pollution. Utility Model Content

[0004] The purpose of this invention is to provide a system that simultaneously realizes the resource utilization of biogas residue and the purification of natural gas, which has the effects of eliminating tar pollution and increasing methane production efficiency.

[0005] The above-mentioned technical objective of this utility model is achieved through the following technical solution: a system for simultaneously realizing the resource utilization of biogas residue and the purification of gas, comprising a receiving hopper, an anaerobic digester, a solid-liquid separator, a material dispersing device, a drying furnace, a pyrolysis furnace, a gas storage tank, and a gas purification unit. The receiving hopper is connected to the feed end of the anaerobic digester via a conveying device. The discharge end of the anaerobic digester is connected to the feed end of the solid-liquid separator. The discharge ends of the material dispersing device and the solid-liquid separator are both connected to the feed end of the drying furnace. The discharge end of the drying furnace is connected to the feed end of the pyrolysis furnace. The discharge end and the gas outlet end of the pyrolysis furnace are connected to the anaerobic digester. The gas outlet end of the anaerobic digester is connected to the gas inlet end of the gas storage tank. The gas outlet end of the gas storage tank is connected to the gas inlet end of the gas purification unit.

[0006] The present invention is further configured such that: the anaerobic fermenter is equipped with a temperature control unit to maintain the temperature inside the tank at 35-38℃, and is equipped with a stirring structure with a stirring speed of 15-20 rpm and a fermentation cycle of 15-20 days.

[0007] A further feature of this invention is that the solid-liquid separator is a screw extrusion separator, and the separated liquid is returned to the anaerobic fermentation tank.

[0008] A further feature of this invention is that the material dispersing device includes a rotating cutter roller and a screen, used to break up agglomerated materials after solid-liquid separation.

[0009] A further feature of this invention is that the heat source of the drying furnace comes from the waste heat of the flue gas from the pyrolysis furnace, and the drying temperature is 80-120℃.

[0010] A further feature of this invention is that the pyrolysis furnace adopts anoxic temperature-controlled pyrolysis with a pyrolysis temperature of 450-550℃, and tar-containing pyrolysis gas is injected into the bottom of the anaerobic fermenter via a gas pump.

[0011] A further feature of this invention is that a tar pyrolyzer is provided between the pyrolysis furnace and the anaerobic fermenter, with a pyrolysis temperature of 600-700℃.

[0012] A further feature of this invention is that the gas storage tank is equipped with a gas mixer and a pressure sensor to maintain the pressure inside the tank at 0.8-1.2 kPa, ensuring the homogenization of the gas components.

[0013] A further feature of this invention is that the gas purification unit includes a water washing tower, a desulfurization tower, and a pressure swing adsorption device connected in sequence, so that the purity of the purified methane meets the standards for natural gas.

[0014] In summary, this invention has the following beneficial effects: It introduces tar-containing pyrolysis gas from a pyrolysis furnace into an anaerobic fermenter, using biochar as an anaerobic microbial promoter to efficiently convert tar into methane within the fermenter. This not only completely eliminates the risk of tar contamination to subsequent gas purification systems but also significantly increases total methane production. Simultaneously, it avoids the complex equipment investment and high operating costs of traditional pyrolysis gas purification processes. The sludge after anaerobic fermentation undergoes solid-liquid separation, crushing, and drying using the residual heat of pyrolysis flue gas, ultimately being pyrolyzed into high-value-added biochar for external supply. The entire process achieves resource utilization of sludge, with no solid residue discharge, addressing the pain point of insufficient volume reduction in traditional anaerobic fermentation technology. Through the synergistic effect of pyrolysis gas purification and anaerobic fermentation, it eliminates the need for multi-stage treatment units such as condensation and electrostatic tar removal required in traditional pyrolysis gas purification, and avoids the generation of corresponding gaseous pollutants, thus preventing environmental impact. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of this utility model.

[0016] In the diagram: 1. Receiving hopper; 2. Anaerobic fermenter; 3. Solid-liquid separator; 4. Material dispersing device; 5. Drying furnace; 6. Pyrolysis furnace; 7. Gas storage tank; 8. Gas purification unit. Detailed Implementation

[0017] The present invention will be further described below with reference to the accompanying drawings of the embodiments thereof.

[0018] Please see Figure 1 In this embodiment of the invention, a system for simultaneously realizing the resource utilization of biogas residue and the purification of biogas slurry includes a receiving hopper 1, an anaerobic digester 2, a solid-liquid separator 3, a material dispersing device 4, a drying furnace 5, a pyrolysis furnace 6, a gas storage tank 7, and a biogas purification unit 8. The receiving hopper 1 is used to receive wet materials such as livestock and poultry manure and organic waste from organic waste. The receiving hopper 1 is connected to the feed end of the anaerobic digester 2 via a conveying device, which is a belt conveyor. After the wet materials undergo sufficient anaerobic fermentation in the anaerobic digester 2, biogas and fermentation liquid are produced. The discharge end of the anaerobic digester 2 is connected to the feed end of the solid-liquid separator 3. The fermentation liquid produced after anaerobic fermentation enters the solid-liquid separator 3 for dehydration. The discharge ends of both the material dispersing device 4 and the solid-liquid separator 3 are connected to the feed end of the drying furnace 5 to dry the incoming dry materials, further improving the dryness of the material. The solid content of the material is determined by the following: the discharge end of the drying furnace 5 is connected to the feed end of the pyrolysis furnace 6; the discharge end and gas outlet of the pyrolysis furnace 6 are connected to the anaerobic digester 2; the pyrolysis furnace 6 is used to perform pyrolysis to produce biochar, tar-containing pyrolysis gas, and tar; the tar-containing pyrolysis gas and tar are introduced into the anaerobic digester 2; adding biochar as a promoter can convert a large amount of tar in the pyrolysis gas into methane, thus purifying the tar-containing pyrolysis gas; at the same time, no tar components remain in the biogas slurry after anaerobic fermentation; the gas outlet of the anaerobic digester 2 is connected to the gas inlet of the gas storage tank 7; the biogas produced by anaerobic fermentation, the purified pyrolysis gas, and the methane converted from tar are stored together in the gas storage tank 7, allowing the components of the gas to be mixed evenly in the gas storage tank 7; the gas outlet of the gas storage tank 7 is connected to the gas inlet of the gas purification unit 8, which is used to purify natural gas.

[0019] In this embodiment, preferably, the anaerobic fermenter 2 is equipped with a temperature control unit to maintain the temperature inside the tank at 35-38℃. The temperature control unit adopts a hot water pan circulation system to maintain the water temperature at 40-45℃, and is equipped with a stirring structure with a stirring speed of 15-20 rpm. The fermentation cycle is 15-20 days. The stirring structure adopts a double-layer paddle stirrer, which stops for 15 minutes every 10 minutes of operation to avoid short-circuiting.

[0020] In this embodiment, preferably, the solid-liquid separator 3 is a screw extrusion separator, which can realize rapid solid-liquid separation of fermentation liquid. The separated liquid is returned to the anaerobic fermentation tank 2, and the liquid diverted out is used as dilution water for new materials.

[0021] In this embodiment, preferably, the material dispersing device 4 includes a rotating cutter roller and a screen, which is used to break up the agglomerated material after solid-liquid separation. The broken material can be screened through the screen to ensure that the particle size meets the qualified requirements.

[0022] In this embodiment, preferably, the heat source of the drying furnace 5 comes from the waste heat of the flue gas in the pyrolysis furnace 6. The waste heat of the flue gas is cooled to 150°C by a heat exchanger before being introduced into the drying furnace 5. The drying temperature is 80-120°C. The drying furnace 5 adopts a counter-current drum drying.

[0023] In this embodiment, preferably, the pyrolysis furnace 6 adopts anoxic temperature-controlled pyrolysis with a pyrolysis temperature of 450-550℃. The produced biochar is cooled and then supplied externally. The pyrolysis gas containing tar is injected into the bottom of the anaerobic fermenter 2 via a gas pump. The pyrolysis furnace 6 is configured as an externally heated rotary kiln structure.

[0024] In this embodiment, preferably, a tar pyrolyzer is provided between the pyrolysis furnace 6 and the anaerobic fermentation tank 2. The pyrolyzer has a built-in nickel-based catalyst and a pyrolysis temperature of 600-700℃, which converts the tar into small molecule gas before it is introduced into the anaerobic fermentation tank 2.

[0025] In this embodiment, preferably, the gas storage tank 7 is equipped with a gas mixer and a pressure sensor to maintain the pressure inside the tank at 0.8-1.2 kPa, ensuring the homogenization of the gas components. The gas mixer is set as a turbine-type gas tempering phase, and the pressure sensor is linked to the variable frequency fan.

[0026] The gas purification unit 8 includes a water washing tower, a desulfurization tower, and a pressure swing adsorption device connected in sequence, so that the purity of the purified methane meets the natural gas standard. The water washing tower removes particulate matter and water-soluble impurities, the desulfurization tower is filled with iron oxide desulfurizing agent to remove H2S, and the pressure swing adsorption device uses 4A molecular sieve to adsorb CO2.

[0027] During use, organic waste (livestock and poultry manure, organic garbage, etc.) is transported from receiving hopper 1 to anaerobic fermentation tank 2. Inside anaerobic fermentation tank 2, a temperature control unit maintains a mesophilic fermentation temperature of 35-38℃. A double-layer paddle agitator operates at a speed of 15-20... The system operates intermittently at rpm (stirring every 10 minutes followed by a 15-minute pause), with a fermentation cycle of 15-20 days. Wet materials are decomposed by anaerobic microorganisms to produce biogas, solid-containing biogas residue, and fermentation broth. The fermentation broth enters a screw extrusion solid-liquid separator 3 for solid-liquid separation. The separated liquid is returned to the anaerobic fermentation tank 2 as dilution water for new materials. Solid biogas residue is crushed and screened by a material dispersing device 4, where a rotating cutter roller breaks up agglomerated materials to a suitable particle size (controlled by a screen). The crushed biogas residue enters a counter-current drum-type dryer 5, where it is dried at 80-120℃ using the waste heat from the flue gas discharged from the pyrolysis furnace 6 (cooled to 150℃ via a heat exchanger), further increasing the solid content. The dried material is then conveyed to an externally heated rotary kiln pyrolysis furnace 6, where it undergoes controlled-temperature pyrolysis at 450-550℃ under anaerobic conditions, producing biochar (for external supply after cooling) and tar-containing materials. Pyrolysis gas; tar-containing pyrolysis gas is first cracked into small molecule gases by a tar cracker (with built-in nickel-based catalyst, 600-700℃). The cracked gas and pyrolysis tar are injected together into the bottom of the anaerobic fermenter 2. Under the catalysis of biochar (as a microbial carrier), the tar components are converted into methane by anaerobic bacteria, realizing in-situ purification of pyrolysis gas. The biogas, tar-converted methane and purified pyrolysis gas produced by the anaerobic fermenter 2 enter the gas storage tank 7. The turbine gas mixer in the gas storage tank 7 homogenizes the gas, and the pressure sensor links the variable frequency fan to maintain the pressure in the tank at 0.8-1.2 kPa. The mixed gas passes through the three-stage treatment of the gas purification unit 8 in sequence: the water washing tower removes particulate matter and water-soluble impurities, the desulfurization tower removes H2S with iron oxide desulfurizing agent, and the pressure swing adsorption device uses 4A molecular sieve to adsorb CO2, finally producing pipeline natural gas that meets the standards.

[0028] The above description is only a preferred embodiment of the present utility model. Therefore, all equivalent changes or modifications made to the structure, features and principles described in the claims of the present utility model patent application are included in the scope of the present utility model patent application.

Claims

1. A system for simultaneously realizing the resource utilization of biogas residue and the purification of fuel gas, comprising a receiving hopper (1), an anaerobic digester (2), a solid-liquid separator (3), a material dispersing device (4), a drying furnace (5), a pyrolysis furnace (6), a gas storage tank (7), and a fuel gas purification unit (8), characterized in that, The receiving hopper (1) is connected to the feed end of the anaerobic fermenter (2) through a conveying device. The discharge end of the anaerobic fermenter (2) is connected to the feed end of the solid-liquid separator (3). The discharge ends of the material dispersing device (4) and the solid-liquid separator (3) are both connected to the feed end of the drying furnace (5). The discharge end of the drying furnace (5) is connected to the feed end of the pyrolysis furnace (6). The discharge end and the gas outlet end of the pyrolysis furnace (6) are connected to the anaerobic fermenter (2). The gas outlet end of the anaerobic fermenter (2) is connected to the gas inlet end of the gas storage tank (7). The gas outlet end of the gas storage tank (7) is connected to the gas inlet end of the gas purification unit (8).

2. The system for simultaneous biogas residue resourceization and gas purification according to claim 1, characterized in that: The anaerobic fermenter (2) is equipped with a temperature control unit to maintain the temperature inside the tank at 35-38℃, and is equipped with a stirring structure with a stirring speed of 15-20 rpm and a fermentation cycle of 15-20 days.

3. The system for simultaneous biogas residue resourceization and gas purification according to claim 1, characterized in that: The solid-liquid separator (3) is a screw extrusion separator, and the separated liquid is returned to the anaerobic fermenter (2).

4. The system for simultaneous biogas residue resourceization and gas purification according to claim 1, characterized in that: The material dispersing device (4) includes a rotating cutter roller and a screen, used to break up agglomerated materials after solid-liquid separation.

5. The system for simultaneous biogas residue valorization and gas cleaning according to claim 1, characterized in that: The heat source of the drying furnace (5) comes from the waste heat of the flue gas from the pyrolysis furnace (6), and the drying temperature is 80-120℃.

6. The system for simultaneously realizing biogas residue resource utilization and gas purification according to claim 1, characterized in that: The pyrolysis furnace (6) adopts oxygen-deficient temperature-controlled pyrolysis with a pyrolysis temperature of 450-550℃. The pyrolysis gas containing tar is injected into the bottom of the anaerobic fermenter (2) via a gas pump.

7. The system for simultaneous biogas residue valorization and gas cleaning according to claim 1, characterized in that: A tar pyrolyzer is provided between the pyrolysis furnace (6) and the anaerobic fermenter (2), with a pyrolysis temperature of 600-700℃.

8. The system for simultaneous biogas residue valorization and gas cleaning according to claim 1, characterized in that: The gas storage tank (7) is equipped with a gas mixer and a pressure sensor to maintain the pressure inside the tank at 0.8-1.2 kPa, ensuring the homogenization of the gas components.

9. The system for simultaneous biogas residue valorization and gas cleaning according to claim 1, characterized in that: The gas purification unit (8) includes a water washing tower, a desulfurization tower and a pressure swing adsorption device connected in sequence, so that the purity of the purified methane meets the natural gas standard.

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