Integrated device for anaerobic fermentation of agricultural waste and micro-aerobic desulfurization of biogas and method of use

Abstract

The application relates to an integrated device for anaerobic fermentation of agricultural waste and micro-oxygen desulfurization of biogas and a use method, comprising an anaerobic reactor and a feeding unit, an online monitoring unit, an air inlet unit and a pH adjusting unit connected with the anaerobic reactor; the inside of the anaerobic reactor comprises, from bottom to top, an anaerobic fermentation zone, a biogas gas distribution zone and a desulfurization zone, the anaerobic fermentation zone is provided with a stirring device, the desulfurization zone is provided with desulfurization fillers, and the desulfurization fillers are loaded with sulfur-oxidizing bacteria; the air inlet unit is connected with the desulfurization zone through an air pipe, the feeding unit is connected with the lower part of the anaerobic fermentation zone, and the online monitoring unit and the pH adjusting unit are connected with the middle and upper parts of the anaerobic fermentation zone; the feeding unit comprises a first raw material tank and a second raw material tank, which are respectively used for pretreating livestock and poultry manure and planting industry organic waste; the outside top of the anaerobic reactor is provided with an exhaust pipe, the middle part is provided with a biogas slurry discharge pipe, and the bottom is provided with a material discharge pipe.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of agricultural waste treatment, and particularly relates to an integrated device for anaerobic fermentation of agricultural waste and micro-oxygen desulfurization of biogas and a use method. BACKGROUND

[0002] China is a large agricultural country, and a large amount of agricultural waste is generated in the breeding industry and the planting industry every year. According to statistics, about 380 million tons of livestock and poultry manure are generated in the breeding industry every year, and about 900 million tons of straw are generated in the planting industry every year. Straw is a kind of biochar with high C / N, and the undigested crude fiber in the feces of ruminants accounts for more than 50% of the total solid content. Both straw and crude fiber are difficult to be directly utilized by anaerobic microorganisms, resulting in low overall fermentation efficiency. However, the main way of resource utilization of livestock and poultry manure at present is still anaerobic fermentation.

[0003] Mixed anaerobic fermentation is a way of putting one or more than two fermentation materials into the same anaerobic fermentation device for fermentation. After mixing, different materials can provide balanced nutrients for microorganisms, increase the diversity of microorganisms, overcome the shortcomings of slow gas production and low fermentation efficiency of single fermentation raw material, and help the anaerobic fermentation, which is one of the research hotspots of agricultural waste resource utilization in recent years.

[0004] Anaerobic fermentation process produces biogas, which is a renewable energy source and plays an important role in filling the gap of natural gas and optimizing the energy structure. The main components of biogas are methane and carbon dioxide, and a small amount of H2S gas. The content of H2S in natural gas is strictly required in national and industry standards. Due to the presence of H2S gas, the activity of methanogenic bacteria in the fermentation system is inhibited, resulting in low gas production efficiency of anaerobic digestion, and the biogas is easy to corrode instruments and metal pipelines in the process of utilization and transportation. Therefore, the biogas must be effectively desulfurized before comprehensive utilization.

[0005] At present, the commonly used biogas desulfurization processes include dry desulfurization, wet desulfurization and biological desulfurization. Dry desulfurization has the problems of high replacement frequency of desulfurizer, difficulty in regeneration, large equipment footprint and low desulfurization efficiency. Wet desulfurization has the problems of high cost, complex operation and management, and easy secondary pollution. Biological desulfurization removes H2S in biogas by using the metabolic action of sulfur-oxidizing bacteria, which is not only economic and safe, but also has low energy consumption and cost, and can recover elemental sulfur through certain reaction conditions.

[0006] At present, the anaerobic fermentation of agricultural organic waste and the desulfurization of biogas are generally separated and operated independently, which increases the investment of biogas transportation and storage links, and also increases the equipment investment and operation and management cost of desulfurization link. The overall process energy consumption of anaerobic fermentation and biogas desulfurization is high, the efficiency is low, and the utilization of valuable products after the process is not reasonable enough. SUMMARY

[0007] In order to solve the above problems, the application provides an integrated device and a use method for anaerobic fermentation of agricultural waste and micro-oxygen desulfurization of biogas, which integrates anaerobic fermentation of agricultural organic waste and biogas desulfurization, uses micro-oxygen in-situ desulfurization technology, introduces a small amount of O2 into the anaerobic system, and makes it react with H2S in the biogas to generate elemental sulfur to achieve the purpose of removing H2S. Since the desulfurization can be directly carried out in the anaerobic system, and the residual oxygen content in the treated biogas is low, the operation safety can be effectively ensured, and the elemental sulfur can be recovered, which greatly reduces the construction cost of the desulfurization device. At the same time, under the premise that the anaerobic reaction is normally carried out, the anaerobic fermentation effect can be promoted, and the agricultural waste can be fully degraded.

[0008] In a first aspect, the integrated device for anaerobic fermentation of agricultural waste and micro-oxygen desulfurization of biogas comprises an anaerobic reactor and a feed unit, an online monitoring unit, an air inlet unit and a pH adjusting unit connected to the anaerobic reactor.

[0009] The inside of the anaerobic reactor comprises, from bottom to top, an anaerobic fermentation zone, a biogas gas distribution zone and a desulfurization zone. The anaerobic fermentation zone is provided with a stirring device, the desulfurization zone is provided with desulfurization filler, and the desulfurization filler is loaded with sulfur-oxidizing bacteria. The air inlet unit is connected to the desulfurization zone through an air pipe, the feed unit is connected to the lower part of the anaerobic fermentation zone, and the online monitoring unit and the pH adjusting unit are connected to the upper part of the anaerobic fermentation zone.

[0010] The feed unit comprises a first raw material tank and a second raw material tank for pretreating livestock and poultry manure and planting organic waste, respectively.

[0011] The outside of the anaerobic reactor is provided with an exhaust pipe at the top, a biogas liquid discharge pipe in the middle and a material discharge pipe at the bottom.

[0012] Optionally, the first raw material tank is connected to the anaerobic reactor through a first raw material conveying pipeline and a first pump to input livestock and poultry manure slurry into the anaerobic fermentation zone; and the second raw material tank is connected to the anaerobic reactor through a second raw material conveying pipeline and a second pump to input planting organic waste crushed material into the anaerobic fermentation zone.

[0013] The feed unit further comprises a waste iron chip storage tank connected to the anaerobic reactor through a third raw material conveying pipeline and a third pump to input pretreated iron chips into the anaerobic fermentation zone.

[0014] Optionally, a gas separation plate is arranged between the anaerobic fermentation zone and the biogas gas distribution zone to prevent a large amount of oxygen in the desulfurization zone from entering the anaerobic fermentation zone.

[0015] The gas separation plate is uniformly provided with a plurality of air holes, and each air hole is provided with a first cover plate which can be opened and closed above the air hole. One side of the first cover plate is hinged to the upper surface of the gas separation plate, and the other side is freely built above the air hole.

[0016] Further optional, one side of the air baffle plate near the hinge of each first cover plate is provided with a corresponding drainage port, that is, the drainage port is arranged on one side of the through hole, and a second cover plate is arranged on the drainage port, and a temporary storage tank is arranged below the drainage port.

[0017] The second cover plate is connected with the first cover plate through a hinge shaft, so that the second cover plate and the first cover plate can rotate around the hinge shaft as a fulcrum.

[0018] Optionally, the biogas distribution area is provided with a horizontally placed distribution plate composed of transversely and longitudinally staggered grids; a first gas inlet is arranged on the side wall of the anaerobic reactor below the distribution plate, and the first gas inlet is connected with the gas inlet unit through a gas pipe.

[0019] A second gas inlet is arranged on the side wall of the desulfurization area, and the second gas inlet is connected with the gas inlet unit through a gas pipe, so as to supplement oxygen in the desulfurization area and promote the biological activity of sulfur-oxidizing bacteria.

[0020] Optionally, the desulfurization filler in the desulfurization area is a three-dimensional net frame structure staggered transversely and longitudinally, and the desulfurization filler is loaded with sulfur-oxidizing bacteria (SOB); when the biogas moves upward and contacts the desulfurization filler, the sulfur-oxidizing bacteria perform biochemical reactions to absorb H2S in the biogas and produce nanoscale granular sulfur; this elemental sulfur has better biological affinity and hydrophilicity and does not affect the growth and metabolism of the sulfur-oxidizing bacteria; with the extension of the process time, the sulfur gradually accumulated on the desulfurization filler and the inactivated biological membrane fall on the distribution plate and the air baffle plate under the action of the upward biogas flow, and finally fall into the anaerobic fermentation area through the drainage port and the temporary storage tank of the air baffle plate, the inactivated biological membrane serves as a carbon source for anaerobic fermentation, and the nanoscale sulfur particles are discharged with the fermentation waste residue from the anaerobic reactor.

[0021] Optionally, the desulfurization filler in the desulfurization area includes a plurality of rotating filler devices arranged in parallel and horizontally from top to bottom, and the rotating filler devices are staggered in the desulfurization area, so that the biogas flows through the desulfurization area in a zigzag manner along the plurality of rotating filler devices.

[0022] The rotating filler device includes at least two rotating shafts, a transmission belt on the rotating shaft, an isolation cover and a biological carrier; the transmission belt is installed outside the rotating shaft and rotates under the driving of the rotating shaft; the transmission belt and the rotating shaft are arranged inside the isolation cover; the transmission belt is detachably connected to the inner wall of the isolation cover through a plurality of connecting rods, so as to drive the isolation cover to rotate together; and the biological carrier is uniformly arranged on the outer surface of the isolation cover and can rotate with the isolation cover.

[0023] Both ends of the rotating shaft are rotatably connected to two opposite side walls of the desulfurization area; one end of the rotating shaft penetrates through the side wall of the desulfurization area and is connected to an external driving motor.

[0024] Optionally, the length direction of the rotating filling device corresponding to the rotation axis is the width direction, and the movement direction of the conveying belt is the length direction. The rotating filling device is provided with a plurality of rows of biological carriers in the length direction of the rotating filling device. The biological carriers are loaded with sulfur-oxidizing bacterial biofilm.

[0025] Each row of biological carriers is a sheet-shaped grid structure. The biological carriers are perpendicular to the outer surface of the isolation cover. The grid structure increases the load of sulfur-oxidizing bacteria and allows biogas to pass through the biological carriers, so that the sulfur-oxidizing bacteria perform biological desulfurization reaction.

[0026] The two ends of the length direction of the rotating filling device are a first end and a second end, respectively. The side wall of the desulfurization area pointed by the first end is a first side wall, and the side wall of the desulfurization area pointed by the second end is a second side wall. Each rotating filling device has the following two installation modes: (1) the first end is close to the first side wall, and the second end is away from the second side wall; (2) the first end is away from the first side wall, and the second end is close to the second side wall. The installation modes of the two rotating filling devices arranged above and below are different, that is, the two rotating filling devices are staggered.

[0027] Optionally, a gas baffle is arranged above one end of the rotating filling device close to the first side wall or close to the second side wall. The gas baffle covers the space between the rotating filling device and the first side wall or the second side wall, so as to prevent a large amount of biogas from flowing upward from the space.

[0028] In a second aspect, a method for using the integrated device is provided, which includes the following steps:

[0029] S100: After removing impurities from livestock and poultry manure, the livestock and poultry manure is input into the first raw material tank. After air-drying and crushing of the organic waste from planting industry, the organic waste is input into the second raw material tank;

[0030] S200: Inoculating the anaerobic fermentation slurry which has been maturely operated into the anaerobic fermentation area, and inputting the livestock and poultry manure and the organic waste from planting industry into the anaerobic fermentation area from the first raw material tank and the second raw material tank, respectively, and controlling the volume of the anaerobic fermentation area to be 2 / 3-3 / 4 of the volume of the anaerobic reactor;

[0031] S300: The stirring device uniformly mixes the livestock and poultry manure, the organic waste from planting industry, and the inoculum, performs anaerobic fermentation, and generates biogas. The fermentation conditions of the anaerobic fermentation area are controlled by the online monitoring unit and the pH adjusting unit;

[0032] S400: The biogas passes through the biogas distribution area and the desulfurization area in sequence, contacts the sulfur-oxidizing bacteria in the desulfurization filler, and is supplied with gas by the gas inlet unit in the desulfurization area, so as to perform biological desulfurization. The desulfurized biogas is discharged through the exhaust pipe.

[0033] S500: The fermented material in the anaerobic fermentation zone is discharged through the material discharge pipe, and the anaerobic fermentation slurry in the anaerobic fermentation zone is discharged through the slurry discharge pipe and used as the inoculum of step S200.

[0034] Optionally, in step S100, the impurities in the livestock and poultry manure include, but are not limited to, sand and stone; the initial total solid content (TS) of the livestock and poultry manure in the first raw material tank is 19-25%.

[0035] The agricultural organic waste is air-dried and crushed into 1-5 cm segments, and a small amount of water can be added. The initial total solid content (TS) of the agricultural organic waste in the second raw material tank is 90-95%.

[0036] Preferably, in step S100, the scrap iron is pretreated and then input into the scrap iron storage tank. The scrap iron can be obtained from mechanical processing plants, equipment processing plants, and other waste such as iron rust waste. The pretreatment of the scrap iron includes: (i) crushing the scrap iron into fragments not greater than 3 cm; (ii) soaking in 0.1-0.2 mol / L NaOH solution to remove surface oil stains; and (iii) rinsing with clean water to remove inorganic particle impurities, thereby obtaining the treated scrap iron.

[0037] In step S200, the livestock and poultry manure contains sufficient nitrogen source. After mixing the livestock and poultry manure and the agricultural waste, the C / N ratio can be effectively adjusted, the methanogenic efficiency of anaerobic fermentation can be significantly improved, and the fermentation potential can be improved. The livestock and poultry manure is selected from one or a combination of two or more of chicken, duck, pig, cow, sheep, camel, and deer manure. The agricultural organic waste is selected from one or a combination of two or more of corn, wheat, or rice straw.

[0038] Preferably, in step S200, the treated scrap iron is input into the anaerobic fermentation zone from the scrap iron storage tank. The mass ratio of the livestock and poultry manure to the agricultural organic waste in the anaerobic fermentation zone can be controlled to be (3-5):1, the TS of the anaerobic fermentation zone is 8-10%, and the concentration of the treated scrap iron is 10-15 g / L.

[0039] The scrap iron in the anaerobic reaction zone is corroded by iron oxides and iron under a micro-aerobic environment, which helps to maintain the pH value of the anaerobic reaction zone between 7 and 8, ensures the activity of methanogenic bacteria, improves the activity of protease and cellulase, promotes hydrolysis and acidification in the anaerobic fermentation process, selectively promotes acetic acid-type fermentation and butyric acid-type fermentation, inhibits propionic acid-type fermentation, and thus improves the methane yield and the methane content in biogas in the subsequent anaerobic process. At the same time, part of the sulfur elements in the anaerobic reaction system is fixed in the form of iron-sulfur compounds to generate FeS precipitates, preventing the part of sulfur from generating H2S and entering the biogas, and reducing the desulfurization load of the desulfurization zone.

[0040] The present application is to combine the biodesulfurization of biogas and the chemical desulfurization in anaerobic zone, the desulfurization zone carries out the in-situ deep desulfurization of biogas micro-oxygen, the generated elemental sulfur and FeS precipitate are discharged with the fermentation materials through the material discharge pipe, and after separation, the waste is utilized. For example, after calcination, it can be used as the desulfurization filler, or used for preparing solid organic fertilizer.

[0041] Optionally, in step S300, the pH value of the anaerobic fermentation zone is 7-8, the temperature is 35-40℃, and the oxidation-reduction potential (ORP value) is -480 to -320 mv, preferably 400 mv.

[0042] Optionally, in step S400, the volume fraction of oxygen in the desulfurization zone is 0.46-0.50%.

[0043] Optionally, in step S500, the volume of the anaerobic fermentation slurry discharged from the slurry discharge pipe 102 is 1 / 4-1 / 3 of the volume of the anaerobic fermentation zone. The slurry can be used as liquid organic fertilizer, and can also be reused as inoculum.

[0044] The integrated device and use method of agricultural waste anaerobic fermentation and biogas micro-oxygen desulfurization have the following beneficial effects:

[0045] 1. The mixed anaerobic fermentation system of agricultural waste can balance the nutrients in the reaction system, overcome the slow gas production and low fermentation efficiency of single fermentation raw material, and realize the effective resource utilization of agricultural waste;

[0046] 2. The desulfurization zone carries out in-situ desulfurization of biogas micro-oxygen, generates nano-sized granular sulfur, realizes biogas desulfurization and elemental sulfur resource utilization, and the generated nano-sized granular sulfur has better biological affinity and hydrophilicity;

[0047] 3. The appropriate amount of scrap iron is added in the anaerobic fermentation process, which ensures the stable operation of the anaerobic fermentation system and further improves the microbial activity, thereby improving the anaerobic fermentation efficiency and gas production performance, and the product FeS can be used as desulfurization filler after separation;

[0048] 4. Through the coupling of micro-oxygen biodesulfurization and chemical desulfurization process, in-situ deep desulfurization of biogas is realized; after the in-situ deep desulfurization of biogas micro-oxygen, the elemental sulfur and FeS precipitate are discharged with the fermentation materials through the material discharge pipe, and after separation, the waste is utilized;

[0049] 5. The iron scrap waste such as iron rust from mechanical processing plants and equipment processing plants is reused. BRIEF DESCRIPTION OF DRAWINGS

[0050] Figure 1 It is a structural schematic view of the integrated device of agricultural waste anaerobic fermentation and biogas micro-oxygen desulfurization.

[0051] Figure 2 Part structure diagram of air isolation plate;

[0052] Figure 3 Structure diagram of rotating filler device installed in desulfurization zone;

[0053] Figure 4 Internal diagram of rotating filler device.

[0054] In the drawings, 1 is an anaerobic reactor, 101 is an exhaust pipe, 102 is a biogas slurry discharge pipe, 103 is a material discharge pipe, 104 is a thermal insulation interlayer, 105 is a biogas analyzer, 106 is a biogas flow meter, 2 is a feeding unit, 201 is a first raw material tank, 202 is a second raw material tank, 203 is a waste iron filings storage tank, 3 is an online monitoring unit, 4 is an air inlet unit, 401 is a fan, 402 is an air flow meter, 5 is a pH adjusting unit, 501 is a pH adjusting device, 502 is a rotameter, 6 is an anaerobic fermentation zone, 7 is a biogas distribution zone, 701 is a distribution plate, 8 is a desulfurization zone, 9 is a desulfurization filler, 10 is an air isolation plate, 1001 is a vent hole, 1002 is a first cover plate, 1003 is a discharge port, 1004 is a second cover plate, 1005 is a hinge shaft, 1006 is a temporary storage tank, 1007 is a third cover plate, 11 is a rotating filler device, 1101 is a rotating shaft, 1102 is a transmission belt, 1103 is an isolation cover, 1104 is a biological carrier, 1105 is a connecting rod, 1106 is a first end, 1107 is a second end, 1108 is a first side wall, 1109 is a second side wall, 1110 is a gas blocking plate, and 12 is a biogas return pipeline. DETAILED DESCRIPTION

[0055] The embodiment provides an integrated device for anaerobic fermentation of agricultural waste and micro-oxygen desulfurization of biogas, as shown in the figure, which comprises an anaerobic reactor 1 and a feeding unit 2, an online monitoring unit 3, an air inlet unit 4 and a pH adjusting unit 5 connected with the anaerobic reactor 1. Figures 1-4

[0056] The inside of the anaerobic reactor 1 comprises, from bottom to top, an anaerobic fermentation zone 6, a biogas distribution zone 7 and a desulfurization zone 8, the anaerobic fermentation zone 6 is provided with a stirring device, the desulfurization zone 8 is provided with a desulfurization filler 9, and the desulfurization filler 9 is loaded with sulfur-oxidizing bacteria; the air inlet unit 4 is connected with the desulfurization zone 8 through a gas pipe, the feeding unit 2 is connected with the lower part of the anaerobic fermentation zone 6, and the online monitoring unit 3 and the pH adjusting unit 5 are connected with the upper middle part of the anaerobic fermentation zone 6.

[0057] The feeding unit 2 comprises a first raw material tank 201 and a second raw material tank 202, which are respectively used for pretreating livestock and poultry manure and planting industry organic waste.

[0058] ​The outer top of the anaerobic reactor 1 is provided with an exhaust pipe 101, the middle part is provided with a biogas slurry discharge pipe 102, and the bottom is provided with a material discharge pipe 103.

[0059] Optionally, the first raw material tank 201 is connected to the anaerobic reactor 1 through a first raw material conveying pipeline and a first pump to input livestock and poultry manure slurry into the anaerobic fermentation zone 6; the second raw material tank 202 is connected to the anaerobic reactor 1 through a second raw material conveying pipeline and a second pump to input planting organic waste crushed material into the anaerobic fermentation zone 6.

[0060] The feeding unit 2 further comprises a waste iron filings storage tank 203, which is connected to the anaerobic reactor 1 through a third raw material conveying pipeline and a third pump to input pretreated iron filings into the anaerobic fermentation zone 6.

[0061] Optionally, the anaerobic reactor 1 is a vertical reaction tank body, the inside of which is coated with anticorrosive paint; the outside of the anaerobic reactor 1 is provided with a heat preservation interlayer 104 for ensuring the fermentation temperature in the anaerobic reactor 1. The heat preservation interlayer 104 is preferably steam heated for controlling the temperature in the heat preservation interlayer 104, and more preferably, the biogas generated by the anaerobic reactor 1 is used as a heat source to heat the steam.

[0062] Optionally, the anaerobic reaction zone accounts for 2 / 3-3 / 4 of the volume of the anaerobic reactor 1 to ensure sufficient desulfurization space and residence time for biogas in the biogas desulfurization zone 8.

[0063] Optionally, the exhaust pipe 101 is sequentially provided with a biogas analyzer 105, a biogas flow meter 106 and a valve from bottom to top, respectively for online real-time analysis of the H2S content in desulfurized biogas and biogas flow, and the valve is used to control the opening and closing of the exhaust pipe.

[0064] The biogas slurry discharge pipe 102 is used for quantitatively discharging biogas slurry after the completion of anaerobic fermentation, and the components of the discharged biogas slurry can be measured in detail as the inoculum for the next anaerobic fermentation.

[0065] Optionally, the pH adjusting unit 5 comprises a pH adjusting device 501 and a rotameter 502, the pH adjusting device 501 is connected to the anaerobic fermentation zone 6 through the rotameter 502, the pH adjusting device 501 is an HCl storage tank and a NaOH storage tank, and the pH value of the anaerobic fermentation zone 6 is adjusted to 7-8.

[0066] Optionally, the gas inlet unit 4 comprises a fan 401 and an air flow meter 402, the fan 401 is connected to the desulfurization zone 8 through the air flow meter 402 and an air pipe to quantitatively provide oxygen for the desulfurization zone 8, maintain a micro-oxygen environment in the desulfurization zone 8, and under the action of sulfur-oxidizing bacteria, use O2 as an electron acceptor to oxidize H2S into nanoscale elemental sulfur to realize micro-oxygen in-situ desulfurization of biogas.

[0067] Optionally, the online monitoring unit 3 comprises a PLC controller, a temperature detector, an orp detector, a liquid level detector, a pH detector, a dissolved oxygen detector and a methane concentration detector, and is in communication connection with corresponding probes, which are all arranged in the anaerobic fermentation zone 6 to control the conditions of the anaerobic fermentation zone 6.

[0068] The PLC controller is linked with the first pump, the second pump and the third pump of the feeding unit 2, the rotor flow meter 502 and the pH adjusting device 501, and the air flow meter 402 and the fan 401.

[0069] Optionally, the desulfurization zone 8 is connected with the anaerobic fermentation zone 6 through a biogas reflux pipeline 12, and the unqualified or excessive biogas is returned to the anaerobic fermentation zone 6.

[0070] Optionally, an air isolation plate 10 is arranged between the anaerobic fermentation zone 6 and the biogas distribution zone 7, to prevent the oxygen in the desulfurization zone 8 from entering the anaerobic fermentation zone 6 in large quantities, and to avoid the explosion caused by the mixing of the biogas in the anaerobic fermentation zone 6 with more oxygen.

[0071] The air isolation plate 10 is uniformly and densely provided with a plurality of air holes 1001, and each air hole 1001 is provided with an openable and closable first cover plate 1002 above it, one side of the first cover plate 1002 is hinged to the upper surface of the air isolation plate 10, and the other side is freely built above the air hole 1001. When the biogas rising from the anaerobic fermentation zone 6 accumulates pressure to a certain extent below the first cover plate 1002, the first cover plate 1002 is opened, and the biogas rises to the biogas distribution zone 7 through the air hole 1001. After the biogas is released, the pressure decreases, and the first cover plate 1002 is automatically closed under its own gravity, isolating the biogas distribution zone 7 from the anaerobic fermentation zone 6, and preventing the oxygen in the desulfurization zone 8 from entering the anaerobic fermentation zone 6 in large quantities. The weight of the first cover plate 1002 is flexibly set according to the rising pressure of the biogas.

[0072] Preferably, the area of the first cover plate 1002 is not less than the area of the corresponding air hole.

[0073] Optionally, a biogas collection zone is arranged between the anaerobic fermentation zone 6 and the air isolation plate 10, which is an empty space above the anaerobic fermentation zone 6, used for collecting biogas and enabling the biogas to accumulate pressure to open the first cover plate 1002 on the air isolation plate 10.

[0074] Further optionally, one drainage port 1003 is arranged on one side of each first cover plate 1002 on the air isolation plate 10, i.e. the drainage port 1003 is arranged on one side of the air hole, and a second cover plate 1004 is arranged on the drainage port 1003, and a temporary storage tank 1006 is arranged below the drainage port 1003.

[0075] The second cover plate 1004 is connected with the first cover plate 1002 through the hinge shaft 1005, so that the second cover plate 1004 and the first cover plate 1002 can rotate around the hinge shaft 1005 as a fulcrum.

[0076] Specifically, the first cover plate 1002 can rotate above the air isolation plate 10 around the hinge shaft 1005, and the second cover plate 1004 can rotate below the air isolation plate 10 around the hinge shaft 1005. When the first cover plate 1002 is opened upward by the biogas rising in the biogas collection area, the second cover plate 1004 rotates downward around the hinge shaft 1005, thereby opening the discharge port 1003, allowing the elemental sulfur obtained by desulfurization and the aged sulfur-oxidizing bacterial membrane on the second cover plate 1004 to fall into the temporary storage tank 1006, and allowing part of the oxygen in the desulfurization area 8 and the biogas distribution area 7 to enter the anaerobic fermentation area 6 through the discharge port 1003 for the reaction of chemical desulfurization by iron filings.

[0077] Optionally, the bottom of the temporary storage tank 1006 is provided with a third cover plate 1007, which is hinged on one side of the bottom of the temporary storage tank 1006. The opening and closing of the third cover plate 1007 controls the pouring of the materials in the temporary storage tank 1006 into the anaerobic fermentation area 6.

[0078] The traditional anaerobic fermentation device separates fermentation and biogas desulfurization, mainly considering that biogas desulfurization needs to introduce air or oxygen. If air or oxygen is mixed with biogas in the fermentation area, it may cause explosion, and is not conducive to maintaining anaerobic fermentation, so the amount of air or oxygen needs to be strictly controlled. The present application integrates anaerobic fermentation and biogas desulfurization in the same reactor, controls the rising of biogas, the descending of air and the discharge of waste in the desulfurization area 8 by setting the air isolation plate 10 between the two areas. The seesaw design of the first cover plate 1002 and the second cover plate 1004 not only meets the demand of discharging biogas through the through hole, but also meets the demand of discharging waste in the desulfurization area 8 through the discharge port 1003, and at the same time, the air in the desulfurization area 8 can enter the anaerobic fermentation area 6 through the through hole and the discharge port 1003; further, the third cover plate 1007 is used to flexibly control the air and waste entering the anaerobic fermentation area 6, which is multiple protection.

[0079] Optionally, the biogas distribution area 7 is provided with a horizontally placed air distribution plate 701, which is composed of horizontal and vertical staggered grids; a first air inlet is arranged on the side wall of the anaerobic reactor 1 below the air distribution plate 701, and the first air inlet is connected with the air inlet unit 4 through an air pipe. Due to the arrangement of the air isolation plate 10, the biogas distribution area 7 and the biogas collection area can be isolated, so that the first air inlet inputs air, which not only does not affect the safety of biogas in the anaerobic fermentation area 6, but also is conducive to the early mixing of air and biogas and the uniform mixing of air and biogas through the air distribution plate 701.

[0080] The desulfurization zone 8 is provided with a second air inlet on its side wall. The second air inlet is connected to the air intake unit 4 through an air pipe to supplement the oxygen in the desulfurization zone 8 and promote the biological activity of sulfur-oxidizing bacteria.

[0081] Optionally, the desulfurization packing 9 in the desulfurization zone 8 is a three-dimensional mesh structure with cross-linked cross-links. Sulfur-oxidizing bacteria (SOB) are loaded on the desulfurization packing 9. When biogas moves upward and comes into contact with the desulfurization packing 9, the sulfur-oxidizing bacteria carry out a biochemical reaction, absorb H2S in the biogas, and produce nano-sized sulfur particles. This elemental sulfur has better biocompatibility and hydrophilicity and will not affect the growth and metabolism of sulfur-oxidizing bacteria. As the process time increases, the sulfur and deactivated biofilm that gradually accumulate on the desulfurization packing 9 fall onto the gas distribution plate 701 and the gas baffle plate 10 in sequence under the action of the upward biogas flow. Finally, it falls into the anaerobic fermentation zone 6 through the discharge port 1003 and the temporary storage tank 1006 of the gas baffle plate 10. The deactivated biofilm serves as the carbon source for anaerobic fermentation, and the nano-sulfur particles are discharged from the anaerobic reactor 1 with the fermentation waste.

[0082] Optionally, the desulfurization packing 9 of the desulfurization zone 8 includes several parallel and horizontally placed rotating packing devices 11 from top to bottom. The rotating packing devices 11 are staggered in the desulfurization zone 8, so that biogas flows through the desulfurization zone 8 in a tortuous manner along the several rotating packing devices 11.

[0083] The rotating packing device 11 includes at least two rotating shafts 1101, a transmission belt 1102, an isolation cover 1103, and a biological carrier 1104 on the rotating shafts 1101. The transmission belt is installed on the outside of the rotating shafts 1101 and rotates under the drive of the rotating shafts 1101. The transmission belt 1102 and the rotating shafts 1101 are located inside the isolation cover 1103. The transmission belt 1102 is detachably connected to the inner wall of the isolation cover 1103 through several connecting rods 1105 to drive the isolation cover 1103 to rotate together. The biological carrier 1104 is evenly distributed on the outer surface of the isolation cover 1103 and can rotate together with the isolation cover 1103.

[0084] The two ends of the rotating shaft 1101 are rotatably connected to the two opposite sidewalls of the desulfurization zone 8, and one end of the rotating shaft 1101 passes through the sidewall of the desulfurization zone 8 and is connected to an external drive motor. That is, the rotating packing device 11 is indirectly fixed to the sidewall of the desulfurization zone 8 through the rotating shaft 1101.

[0085] Further optional, the rotating shaft 1101 extends out of the isolation cover 1103, the part connecting the side wall of the desulfurization zone 8 is provided with a protective sleeve, which is used to prevent pollution and corrosion by biogas or elemental sulfur, and falling biological membrane tissue; the length of the isolation cover 1103 is slightly smaller than the length of the rotating shaft 1101, which allows the isolation cover 1103 to move with the conveyor belt without scratching the side wall of the desulfurization zone 8; the two sides of the isolation cover 1103 facing the end of the rotating shaft 1101 are not provided with biological carriers 1104, and the side facing the circumferential axis of the rotating shaft 1101 is provided with biological carriers 1104.

[0086] One end of the connecting rod 1105 is detachably connected to the inner wall of the isolation cover 1103, and the other end is detachably connected to the outer surface of the conveyor belt. The connecting rod 1105 can be made of hard plastic, so that there is a certain buffer between the isolation cover 1103 and the conveyor belt, protecting the isolation cover 1103 and the biological carrier 1104. The isolation cover 1103 is made of flexible material, so that it can rotate 360° with the conveyor belt.

[0087] Optionally, the rotating filler device 11 corresponds to the length direction of the rotating shaft 1101, which is the width direction, and corresponds to the movement direction of the conveyor belt, which is the length direction. The rotating filler device 11 is provided with a plurality of rows of biological carriers 1104 in the length direction of itself, and the biological carriers 1104 are loaded with sulfur-oxidizing bacterial biofilm.

[0088] Each row of biological carriers 1104 is a sheet-like grid structure, and the biological carriers 1104 are perpendicular to the outer surface of the isolation cover 1103. The grid structure increases the load of sulfur-oxidizing bacteria while allowing biogas to pass through the biological carriers 1104 for biological desulfurization reaction.

[0089] The two ends of the rotating filler device 11 in the length direction of itself are respectively a first end 1106 and a second end 1107. The side wall of the desulfurization zone 8 pointed by the first end 1106 is a first side wall 1108, and the side wall of the desulfurization zone 8 pointed by the second end 1107 is a second side wall 1109. Each rotating filler device 11 has the following two installation modes: (1) the first end 1106 is close to the first side wall 1108 while the second end 1107 is away from the second side wall 1109; (2) the first end 1106 is away from the first side wall 1108 while the second end 1107 is close to the second side wall 1109. The installation modes of the two rotating filler devices 11 above and below are different, that is, the two rotating filler devices 11 above and below are staggered.

[0090] Optionally, the rotating filler device 11 is provided with a gas baffle 1110 above one end of the first side wall 1108 or the second side wall 1109, the gas baffle 1110 covers the space between the rotating filler device 11 and the first side wall 1108 or the second side wall 1109, for preventing a large amount of biogas from flowing upward from the space, thus, the staggered rotating filler devices 11 and the corresponding gas baffles 1110 form a serpentine gas channel, allowing biogas to pass through, prolonging the residence time of biogas in the desulfurization zone 8, promoting the contact between biogas and the biological carrier 1104, and improving the biochemical desulfurization efficiency.

[0091] Preferably, the rows of biological carriers 1104 on the opposite surfaces of two adjacent rotating filler devices 11 are staggered with each other, forming a zigzag structure, that is, the lower part of a row of biological carriers 1104 on the lower surface of the upper rotating filler device 11 is between the upper parts of two rows of biological carriers 1104 on the upper surface of the lower rotating filler device 11, which improves the layout density of the biological carriers 1104.

[0092] Preferably, the movement direction of the biological carrier 1104 is opposite to the gas flow direction of the adjacent biogas, that is, the cross-flow direction.

[0093] Embodiment 1

[0094] The integrated device for anaerobic fermentation of agricultural waste and micro-aerobic desulfurization of biogas used in this embodiment includes the above-mentioned anaerobic reactor and the feed unit, online monitoring unit, gas inlet unit, and pH adjusting unit connected with the anaerobic reactor; the inside of the anaerobic reactor is divided into an anaerobic fermentation zone, a biogas collection zone, a biogas distribution zone, and a desulfurization zone from bottom to top; and is provided with the above-mentioned gas isolation plate, gas distribution plate, first gas inlet, second gas inlet, and rotating filler device; the gas isolation plate is provided with a through hole, a discharge port, a first cover plate, and a second cover plate; the rotating filler device includes a rotating shaft, a conveyor belt, an isolation cover, and a biological carrier; the above-mentioned optional and preferred schemes are used for each component or each unit area.

[0095] The use method of the integrated device described in this embodiment includes the following steps:

[0096] (1) The cow dung from a certain farm in Henan Province is input into the first raw material tank 201 after removing impurities such as sand and stones; the organic waste of planting industry (wheat straw planted by a farmer in a certain administrative village in Xinxiang City) is dried and crushed to obtain 3 cm segments, which are input into the second raw material tank 202;

[0097] The initial total solid content (TS) of the livestock and poultry manure in the first raw material tank 201 is 19%; a small amount of water is added to the second raw material tank 202, and the initial total solid content (TS) of the organic waste of planting industry is 90%;

[0098] The pretreated scrap iron is input into the scrap iron storage tank 203. The scrap iron is rusted waste from a mechanical processing factory in Zhengzhou, and the surface is covered with rust. The pretreatment of the scrap iron includes: (i) crushing the scrap iron into pieces not larger than 3 cm; (ii) soaking in 0.1 mol / L NaOH solution to remove surface oil stains; (iii) rinsing with clean water to remove inorganic particle impurities, thereby obtaining the treated scrap iron.

[0099] (2) Inoculating the anaerobic fermentation slurry that has been maturely operated into the anaerobic fermentation zone 6, inputting the livestock and poultry manure from the first raw material tank 201, the planting industry organic waste from the second raw material tank 202, and the treated scrap iron from the scrap iron storage tank 203 into the anaerobic fermentation zone 6, and controlling the anaerobic fermentation zone 6 to occupy 2 / 3 of the volume of the anaerobic reactor 1.

[0100] Controlling the mass ratio of the livestock and poultry manure to the planting industry organic waste in the anaerobic fermentation zone 6 to be 3:1, the TS of the anaerobic fermentation zone 6 to be 8%, and the concentration of the treated scrap iron to be 10 g / L.

[0101] (3) Uniformly mixing the livestock and poultry manure, the planting industry organic waste, the scrap iron, and the inoculum by the stirring device, performing anaerobic fermentation, and generating biogas, and controlling the fermentation conditions of the anaerobic fermentation zone 6 by the online monitoring unit 3 and the pH adjusting unit 5.

[0102] The pH value of the anaerobic fermentation zone 6 is 7, the temperature is 37℃, and the oxidation-reduction potential (ORP value) is 400 mv.

[0103] (4) The biogas passes through the biogas distribution zone 7 and the desulfurization zone 8 in sequence, contacts with sulfur-oxidizing bacteria in the desulfurization filler 9, and is supplied with gas by the gas inlet unit 4 to perform biological desulfurization in the desulfurization zone 8. The desulfurized biogas is discharged through the exhaust pipe 101. The volume fraction of oxygen in the desulfurization zone is accurately controlled to be 0.50% by the gas inlet unit.

[0104] S500: The material fermented in the anaerobic fermentation zone 6 is discharged through the material discharge pipe 103, and the anaerobic fermentation slurry in the anaerobic fermentation zone 6 is discharged through the slurry discharge pipe 102. The volume of the discharged anaerobic fermentation slurry is 1 / 3 of the volume of the anaerobic fermentation zone 6, and serves as the inoculum of step S200.

[0105] The operation effect of the embodiment is as follows:

[0106] ① After the stable operation of the anaerobic fermentation zone 6, the H2S concentration in the biogas is 16.5-17.5 g / m 3 ;

[0107] ② After the completion of desulfurization in the desulfurization zone, the H2S concentration in the biogas detected by the biogas analyzer 105 is ≤6 mg / m 3 , the desulfurization rate is >99%, the sulfur element is converted into elemental sulfur, and the elemental sulfur generation rate is all above 96%.

[0108] ③The COD removal rate of the discharged anaerobic fermentation biogas slurry is 65%, the methane yield is 350 mL / gCOD, and the sulfate content is 31 mg / L;

[0109] ④FeS is detected in the material discharged from the material discharge pipe.

[0110] Example 2

[0111] The integrated device for anaerobic fermentation of agricultural waste and micro-oxygen desulfurization of biogas and its use method used in this example are the same as those in Example 1, except that the mass ratio of livestock and poultry manure to planting industry organic waste in the anaerobic fermentation zone is 5:1.

[0112] The COD removal rate of the discharged anaerobic fermentation biogas slurry in this example is 67%, and the methane yield is 360 mL / gCOD

[0113] Example 3

[0114] The integrated device for anaerobic fermentation of agricultural waste and micro-oxygen desulfurization of biogas and its use method used in this example are the same as those in Example 1, except that the mass ratio of livestock and poultry manure to planting industry organic waste in the anaerobic fermentation zone is 2.9:1.

[0115] The COD removal rate of the discharged anaerobic fermentation biogas slurry in this example is 58%, and the methane yield is 320 mL / gCOD

[0116] Example 4

[0117] The integrated device for anaerobic fermentation of agricultural waste and micro-oxygen desulfurization of biogas and its use method used in this example are the same as those in Example 1, except that the concentration of treated iron filings in the anaerobic fermentation zone is 15 g / L.

[0118] The sulfate content of the discharged anaerobic fermentation biogas slurry in this example is 29 mg / L, and the addition of iron filings helps to precipitate and remove sulfur in the material.

[0119] Example 5

[0120] The integrated device for anaerobic fermentation of agricultural waste and micro-oxygen desulfurization of biogas and its use method used in this example are the same as those in Example 1, except that the concentration of treated iron filings in the anaerobic fermentation zone is 9 g / L.

[0121] The sulfate content of the discharged anaerobic fermentation biogas slurry in this example is 48 mg / L.

[0122] Example 6

[0123] The agricultural waste anaerobic fermentation and biogas micro-oxygen desulfurization integrated device and its use method used in this embodiment are the same as those in embodiment 1, except that the volume fraction of oxygen in the desulfurization zone is 0.46%, and the desulfurization rate is 98.5% after desulfurization is completed in the desulfurization zone, and the elemental sulfur generation rate is all above 95%.

[0124] Embodiment 7

[0125] The agricultural waste anaerobic fermentation and biogas micro-oxygen desulfurization integrated device and its use method used in this embodiment are the same as those in embodiment 1, except that the volume fraction of oxygen in the desulfurization zone is 0.45%, and the desulfurization rate is 95% after desulfurization is completed in the desulfurization zone, and the elemental sulfur generation rate is all above 90%.

[0126] Embodiment 8

[0127] The agricultural waste anaerobic fermentation and biogas micro-oxygen desulfurization integrated device and its use method used in this embodiment are the same as those in embodiment 1, except that the pH value of the anaerobic fermentation zone is 8, and the H2S concentration in the biogas is 12.5-14.5 g / m 3 after the anaerobic fermentation zone 6 is stably operated, which reduces the desulfurization load.

[0128] Embodiment 9

[0129] The agricultural waste anaerobic fermentation and biogas micro-oxygen desulfurization integrated device and its use method used in this embodiment are the same as those in embodiment 1, except that the pH value of the anaerobic fermentation zone is 6.9, and the H2S concentration in the biogas is 18.4-20.1 g / m 3 after the anaerobic fermentation zone 6 is stably operated, which slightly increases the desulfurization load, the H2S concentration in the biogas detected by the biogas analyzer 105 is ≤18 mg / m 3 , and the desulfurization rate is also higher.

[0130] Embodiment 10

[0131] The agricultural waste anaerobic fermentation and biogas micro-oxygen desulfurization integrated device and its use method used in this embodiment are the same as those in embodiment 1, except that the desulfurization filler of the integrated device is a three-dimensional net frame structure staggered horizontally and vertically, and loaded with sulfur-oxidizing bacteria, and the desulfurization rate is 86% after desulfurization is completed in the desulfurization zone.

[0132] Embodiment 11

[0133] The agricultural waste anaerobic fermentation and biogas micro-oxygen desulfurization integrated device and its use method used in this embodiment are the same as those in embodiment 1, except that the integrated device does not set an air separation plate, and the desulfurization rate is 85%.

[0134] Embodiment 12

[0135] The integrated device for anaerobic fermentation of agricultural waste and micro-oxygen desulfurization of biogas and the use method thereof used in the embodiment are the same as those in embodiment 10, except that the integrated device is not provided with an air isolation plate, and the desulfurization rate is 79%.

Claims

1. An integrated device for anaerobic fermentation of agricultural waste and micro-oxygenic desulfurization of biogas, characterized in that, The anaerobic reactor is connected with a feeding unit, an online monitoring unit, an air inlet unit and a pH adjusting unit; The inside of the anaerobic reactor comprises, from bottom to top, an anaerobic fermentation zone, a biogas distribution zone and a desulfurization zone, the anaerobic fermentation zone is provided with a stirring device, the desulfurization zone is provided with desulfurization filler, and the desulfurization filler is loaded with sulfur-oxidizing bacteria; the air inlet unit is connected with the desulfurization zone through an air pipe, the feeding unit is connected with the lower part of the anaerobic fermentation zone, and the online monitoring unit and the pH adjusting unit are connected with the upper part of the anaerobic fermentation zone; The feeding unit comprises a first raw material tank and a second raw material tank, which are respectively used for pretreating livestock and poultry manure and planting industry organic waste; The outside of the anaerobic reactor is provided with an exhaust pipe at the top, a biogas slurry discharge pipe at the middle and a material discharge pipe at the bottom; An air isolation plate is arranged between the anaerobic fermentation zone and the biogas distribution zone, which is used for preventing oxygen in the desulfurization zone from entering the anaerobic fermentation zone in large quantities; A plurality of air holes are uniformly arranged on the air isolation plate, a first cover plate which can be opened and closed is arranged above each air hole, one side of the first cover plate is hinged to the upper surface of the air isolation plate, and the other side is freely arranged above the air hole; One side of the air isolation plate close to the hinge of each first cover plate is correspondingly provided with a discharge port, the discharge port is arranged on one side of the through hole, a second cover plate is arranged on the discharge port, and a temporary storage tank is arranged below the discharge port; The second cover plate is connected with the first cover plate through a hinge shaft, so that the second cover plate and the first cover plate can rotate around the hinge shaft as a fulcrum. A third cover plate is arranged at the bottom of the temporary storage tank, the third cover plate is hinged to one side of the bottom of the temporary storage tank, and the opening and closing of the third cover plate controls the pouring of the materials in the temporary storage tank into the anaerobic fermentation zone.

2. The integrated device of claim 1, wherein, The first raw material tank is connected with the anaerobic reactor through a first raw material conveying pipeline and a first pump, and livestock and poultry manure slurry is input into the anaerobic fermentation zone; the second raw material tank is connected with the anaerobic reactor through a second raw material conveying pipeline and a second pump, and planting industry organic waste crushed material is input into the anaerobic fermentation zone; The feeding unit further comprises a waste iron chip storage tank, which is connected with the anaerobic reactor through a third raw material conveying pipeline and a third pump, and pretreated iron chips are input into the anaerobic fermentation zone.

3. The integrated device of claim 1, wherein, The desulfurization filler in the desulfurization zone comprises a plurality of rotating filler devices which are arranged in parallel and horizontally from top to bottom, the rotating filler devices are staggered arranged in the desulfurization zone, so that the biogas flows through the desulfurization zone along the rotating filler devices in a zigzag manner; The rotating filler device comprises at least two rotating shafts, a transmission belt, an isolation cover and a biological carrier on the rotating shafts, the transmission belt is arranged outside the rotating shaft and rotates under the driving of the rotating shaft, the transmission belt and the rotating shaft are arranged in the isolation cover, the transmission belt is detachably connected with the inner wall of the isolation cover through a plurality of connecting rods, and the biological carrier is uniformly arranged on the outer surface of the isolation cover and can rotate with the isolation cover. The two ends of the rotating shaft are respectively rotatably connected with two opposite side walls of the desulfurization zone, one end of the rotating shaft penetrates through the side wall of the desulfurization zone and is connected with an external driving motor.

4. The integrated device of claim 3, wherein, The length direction of the rotating filler device corresponding to the rotation axis is the width direction, and the movement direction of the conveying belt is the length direction. The rotating filler device is provided with a plurality of rows of biological carriers in the length direction of the rotating filler device. The biological carriers are loaded with sulfur-oxidizing bacterial biofilm. Each row of biological carriers is a sheet-like grid structure. The biological carriers are perpendicular to the outer surface of the isolation cover. The grid structure increases the load of sulfur-oxidizing bacteria and allows biogas to pass through the biological carriers. The sulfur-oxidizing bacteria perform biological desulfurization reaction.

5. The integrated device of claim 4, wherein, The two ends of the length direction of the rotating filler device are the first end and the second end, respectively. The side wall of the desulfurization area pointed by the first end is the first side wall, and the side wall of the desulfurization area pointed by the second end is the second side wall. Each rotating filler device has the following two installation modes: (1) the first end is close to the first side wall, and the second end is away from the second side wall; (2) the first end is away from the first side wall, and the second end is close to the second side wall. The installation modes of the two rotating filler devices arranged above and below each other are different, so that the two rotating filler devices are staggered.

6. The integrated device of claim 5, wherein, A gas baffle is arranged above one end of the rotating filler device close to the first side wall or close to the second side wall. The gas baffle covers the space between the rotating filler device and the first side wall or the second side wall, preventing a large amount of biogas from flowing upward from the space.

7. The method of using the integrated device of claim 2, wherein, The method comprises the following steps: S100: After removing impurities from livestock and poultry manure, the livestock and poultry manure is input into the first raw material tank; After the agricultural organic waste is dried and crushed, the agricultural organic waste is input into the second raw material tank; S200: Inoculate the mature anaerobic fermentation slurry into the anaerobic fermentation area. The first raw material tank and the second raw material tank input the livestock and poultry manure and the agricultural organic waste into the anaerobic fermentation area, respectively. The volume of the anaerobic fermentation area accounts for 2 / 3-3 / 4 of the volume of the anaerobic reactor. S300: The stirring device uniformly mixes the livestock and poultry manure, the agricultural organic waste, and the inoculum. The anaerobic fermentation is carried out, and biogas is generated. The online monitoring unit and the pH adjusting unit control the fermentation conditions of the anaerobic fermentation area. S400: The biogas passes through the biogas distribution area and the desulfurization area in sequence, contacts the sulfur-oxidizing bacteria in the desulfurization filler, and is supplied with gas at the gas inlet unit in the desulfurization area. Biological desulfurization is carried out. The desulfurized biogas is discharged through the exhaust pipe. S500: The fermented material in the anaerobic fermentation area is discharged through the material discharge pipe. The anaerobic fermentation slurry in the anaerobic fermentation area is discharged through the slurry discharge pipe and used as the inoculum of step S200.

8. The method of use of claim 7, wherein, In step S100, the pretreated scrap iron is input into the scrap iron storage tank. In step S200, the scrap iron storage tank inputs the treated scrap iron into the anaerobic fermentation area. The mass ratio of livestock and poultry manure to agricultural organic waste in the anaerobic fermentation area is (3-5):

1. The TS of the anaerobic fermentation area is 8-10%. The concentration of the treated scrap iron is 10-15 g / L.

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