Sludge and livestock and poultry manure combined treatment system

Abstract

The utility model belongs to the field of organic solid waste treatment, and relates to a sludge and livestock and poultry manure combined treatment system which can solve the problem that the carbon nitrogen ratio of single livestock and poultry manure is unbalanced, shorten the anaerobic fermentation period, improve the biogas production rate and reduce the production cost. The system comprises a blending water tank, a desanding device, a mixing tank, a first-stage anaerobic fermentation tank, a second-stage anaerobic fermentation tank and a solid-liquid separation device which are connected in sequence, the first-stage anaerobic fermentation tank and the second-stage anaerobic fermentation tank are both connected with a biogas treatment system, livestock and poultry manure is introduced into the blending water tank, municipal sludge and a catalyst are introduced into the mixing tank, and the solid-liquid separation device is connected with the second-stage anaerobic fermentation tank. A liquid outlet of the solid-liquid separation device is connected with an ammonia stripping device, a liquid outlet of the ammonia stripping device is connected with the blending water tank, and a gas outlet of the ammonia stripping device is connected with an ammonia recovery device.

Description

Technical Field

[0001] This utility model belongs to the field of organic solid waste treatment, and relates to a combined treatment system for sludge and livestock and poultry manure. Background Technology

[0002] There are different technical approaches to treating livestock and poultry manure, among which anaerobic fermentation is increasingly being used. Through anaerobic fermentation, livestock and poultry manure can be decomposed into biogas, biogas residue, and biogas slurry. After purification, biogas can be produced into biomethane, while biogas residue and biogas slurry can be used as raw materials for solid fertilizer and liquid fertilizer, respectively.

[0003] Anaerobic fermentation is a process in which a series of microorganisms decompose organic matter into substances such as methane, carbon dioxide, and water through stages such as hydrolysis, hydrogen production, acetic acid production, and methanogenesis in a fermentation substrate.

[0004] Hydrolysis and acidification stage: Under anaerobic conditions, large organic molecules are broken down into smaller organic molecules, such as amino acids, monosaccharides, and fatty acids, by hydrolytic enzymes. These smaller organic molecules then enter the hydrogen production and acetic acid production stage.

[0005] Hydrogen- and acetic acid-producing stage: In this stage, small organic molecules are converted into acetic acid and hydrogen gas by hydrogen- and acetic acid-producing bacteria. Simultaneously, some of the acetic acid is further converted into methane.

[0006] Methanation stage: In the methanation stage, acetic acid and hydrogen are converted into methane and carbon dioxide. This process is carried out by a group of specialized anaerobic microorganisms called methanogens. Methanogens grow and reproduce slowly in anaerobic environments, therefore requiring sufficient reaction time and favorable environmental conditions to ensure their growth and metabolism.

[0007] Microbial growth requires a variety of nutrients, the most important of which are carbon and nitrogen sources. A suitable carbon-to-nitrogen ratio can promote rapid microbial growth and population expansion. Livestock and poultry manure, as a type of organic solid waste, is rich in carbon and nitrogen sources. However, in certain types of livestock and poultry manure (such as chicken manure), the carbon-to-nitrogen ratio is imbalanced, failing to meet the actual nutritional requirements of microorganisms during growth. This leads to increased anaerobic fermentation time and low gas production rate. Utility Model Content

[0008] To address the problems of imbalanced carbon-nitrogen ratio, long fermentation cycle, and low biogas production rate in anaerobic fermentation of single livestock and poultry manure, this invention proposes a combined treatment system for sludge and livestock and poultry manure, which can solve the problem of imbalanced carbon-nitrogen ratio in single livestock and poultry manure, shorten the anaerobic fermentation cycle, and improve biogas production rate.

[0009] The technical solution is as follows: a combined treatment system for sludge and livestock manure, comprising a mixing tank, a sand removal device, a mixing tank, a primary anaerobic fermentation tank, a secondary anaerobic fermentation tank, and a solid-liquid separation device connected in sequence. The primary and secondary anaerobic fermentation tanks are both connected to a biogas treatment system. Livestock manure is introduced into the mixing tank, and municipal sludge and a catalyst are introduced into the mixing tank. The liquid outlet of the solid-liquid separation device is connected to an ammonia stripping device, the liquid outlet of the ammonia stripping device is connected to the mixing tank, and the gas outlet is connected to an ammonia recovery device.

[0010] A further feature is that the primary anaerobic fermenter and the secondary anaerobic fermenter have the same structure, both including a tank body. The tank body is provided with a vertically arranged first stirring mechanism and a horizontally arranged second stirring mechanism. The first stirring mechanism includes a hydraulic cylinder fixed to a rotating shaft. The piston rod end of the hydraulic cylinder is connected to a first motor through a mounting base. The motor shaft of the first motor is connected to a first stirrer. The two ends of the rotating shaft are slidably connected to an annular rolling groove installed on the inner wall of the tank body. A drive mechanism is installed on the rotating shaft. The second stirring mechanism includes a second motor installed on the outer wall of the tank body. The motor shaft of the second motor is connected to a second stirrer that penetrates the side wall of the tank body.

[0011] The biogas treatment system includes a biogas purification device connecting the primary anaerobic digester and the secondary anaerobic digester. The outlet of the biogas purification device is connected to the inlet of the gas storage tank, the outlet of the gas storage tank is connected to a purification device, and the gas storage tank is also connected to an emergency flare.

[0012] The solid-liquid separation device is a plate and frame filter press;

[0013] The chemical absorption liquid placed in the ammonia recovery device is one of carbonic acid, sulfuric acid, hydrochloric acid, or nitric acid.

[0014] By adopting this invention, the imbalance of carbon-nitrogen ratio in municipal sludge and livestock and poultry manure can be compensated for by combining them. In the process of joint anaerobic fermentation, the mixture can be fully fermented in two-stage anaerobic fermentation tanks, which can significantly shorten the anaerobic fermentation cycle and improve the biogas production rate. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the system of this utility model;

[0016] Figure 2 This is a schematic diagram of the internal structure of the tank.

[0017] Figure 3 This is a schematic diagram showing the interaction between the traveling wheel and the rolling groove. Detailed Implementation

[0018] See Figure 1 , Figure 2 , Figure 3 As shown, a combined treatment system for sludge and livestock manure includes a mixing tank 1, a sand removal device 2, a mixing tank 3, a primary anaerobic digester 4, a secondary anaerobic digester 5, and a solid-liquid separation device 6 connected in sequence. The primary anaerobic digester 4 and the secondary anaerobic digester 5 are both connected to a biogas treatment system. The biogas treatment system includes a biogas purification device 7 connecting the primary anaerobic digester 4 and the secondary anaerobic digester 5. The outlet of the biogas purification device 7 is connected to the inlet of a gas storage tank 8, and the outlet of the gas storage tank 8 is connected to a purification device 9. The gas storage tank 8 is also connected to an emergency flare 10, which serves as an emergency device to burn excess purified biogas in the gas storage tank 8 when the biogas purification device 9 malfunctions.

[0019] The mixing tank 1 is filled with livestock and poultry manure, which can adjust the moisture content of the manure. The mixing tank 3 is filled with municipal sludge and catalyst. The catalyst can catalyze the anaerobic fermentation reaction of the sludge and livestock and poultry manure, and improve the gas production rate of the system. The catalyst is composed of iron powder and biological activated carbon.

[0020] The primary anaerobic fermenter 4 and the secondary anaerobic fermenter 5 have the same structure, both including a tank body 13. A vertically arranged first stirring mechanism and a horizontally arranged second stirring mechanism are installed inside the tank body 13. Multiple first and second stirring mechanisms can be arranged alternately as needed. The first stirring mechanism includes a hydraulic cylinder 15 fixed to a rotating shaft 14. The piston rod end of the hydraulic cylinder 15 is connected to a first motor 16 via a mounting base. The motor shaft of the first motor 16 is connected to a first agitator 17. Both ends of the rotating shaft 14 are slidably connected to an annular rolling groove 18 installed on the inner wall of the tank body 13. A drive mechanism is installed on the rotating shaft 14, including a drive motor 22. The drive motor drives the rotating shaft 14... The walking wheels 19 at both ends are slidably supported in the annular rolling groove 18. The drive motor 22 drives the walking wheels 19 to rotate through the bevel gear structure, thereby driving the rotating shaft 14 to rotate around the center of the tank body 13. The first agitator 17 also rotates in a circle. The second agitation mechanism includes a second motor 20 installed on the outer wall of the tank body. The motor shaft of the second motor 20 is connected to the second agitator 21 that passes through the side wall of the tank body 13. The materials in the tank body can be fully mixed by using the first agitator 17 and the second agitator 21. Moreover, the first agitator 17 can be raised and lowered to achieve stirring without dead angles. In the figure, 22 is the biogas outlet, 23 is the material inlet, and 24 is the material outlet.

[0021] The liquid outlet of the solid-liquid separation device 6 is connected to the ammonia stripping device 11, the liquid outlet of the ammonia stripping device 11 is connected to the blending water tank 1, and the gas outlet is connected to the ammonia recovery device 12. The solid-liquid separation device 6 is a plate and frame filter press.

[0022] Chicken manure with a moisture content of approximately 83% is diluted in mixing tank 1 with deammoniated low-ammonia reflux biogas slurry, increasing the moisture content to approximately 90%. The diluted chicken manure undergoes sand removal in desanding equipment 2; the separated sand can be used as building material raw material. The sand-removed chicken manure then enters mixing tank 3, where it undergoes preliminary mixing with municipal sludge and catalyst. The mixture then enters primary anaerobic digester 4 to initiate the first stage of fermentation. Under the action of multi-stage agitators in primary anaerobic digester 4, the materials are thoroughly mixed. The biogas produced in primary anaerobic digester 4 enters biogas purification device 7 for purification, removing impurities such as water vapor and hydrogen sulfide. Part of the fermented material is pumped into secondary anaerobic digester 5 for continued fermentation, and the resulting biogas also enters biogas purification device 7. The purified biogas is stored in gas storage tank 8 and further purified by subsequent purification devices to form high-purity biogas.

[0023] The fermentation material in the secondary anaerobic digester 5 is processed by a plate and frame filter press to form biogas residue and biogas slurry. The biogas residue can be used as raw material for bio-fertilizer, and the biogas slurry enters the ammonia stripping device 11. After stripping, the ammonia in the biogas slurry forms ammonia gas, which volatilizes from the biogas slurry and enters the sulfuric acid solution in the ammonia recovery device 12 to produce ammonium sulfate crystals, which can be recovered to form fertilizer. The low-ammonia biogas slurry after ammonia removal is returned to the blending pool 1 for reuse.

Claims

1. A combined treatment system for sludge and livestock manure, characterized in that, It includes a mixing tank, a sand removal device, a mixing tank, a primary anaerobic fermentation tank, a secondary anaerobic fermentation tank, and a solid-liquid separation device connected in sequence. The primary and secondary anaerobic fermentation tanks are both connected to a biogas treatment system. The mixing tank is fed with livestock and poultry manure, and the mixing tank is fed with municipal sludge and a catalyst. The liquid outlet of the solid-liquid separation device is connected to an ammonia stripping device, the liquid outlet of the ammonia stripping device is connected to the mixing tank, and the gas outlet is connected to an ammonia recovery device.

2. The combined treatment system for sludge and livestock manure according to claim 1, characterized in that, The primary anaerobic fermenter and the secondary anaerobic fermenter have the same structure, both including a tank body. The tank body is equipped with a vertically arranged first stirring mechanism and a horizontally arranged second stirring mechanism. The first stirring mechanism includes a hydraulic cylinder fixed to a rotating shaft. The piston rod end of the hydraulic cylinder is connected to a first motor through a mounting base. The motor shaft of the first motor is connected to a first stirrer. The two ends of the rotating shaft are slidably connected to an annular rolling groove installed on the inner wall of the tank body. A drive mechanism is installed on the rotating shaft. The second stirring mechanism includes a second motor installed on the outer wall of the tank body. The motor shaft of the second motor is connected to a second stirrer that penetrates the side wall of the tank body.

3. The combined treatment system for sludge and livestock manure according to claim 1, characterized in that, The biogas treatment system includes a biogas purification device connecting the primary anaerobic digester and the secondary anaerobic digester. The outlet of the biogas purification device is connected to the inlet of the gas storage tank, and the outlet of the gas storage tank is connected to a purification device. The gas storage tank is also connected to an emergency flare.

4. The combined treatment system for sludge and livestock manure according to claim 1, characterized in that, The solid-liquid separation device is a plate and frame filter press.

5. The combined treatment system for sludge and livestock manure according to claim 1, characterized in that, The chemical absorption liquid placed in the ammonia recovery device is one of carbonic acid, sulfuric acid, hydrochloric acid, or nitric acid.

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