CN101805753A - Method of producing biogas through high-solid two-phase three-stage anaerobic digestion by using perishable organic wastes - Google Patents

Abstract

The invention provides a method for producing biogas through high-solid two-phase three-stage anaerobic digestion by using perishable organic wastes, which comprises the following steps: the perishable organic wastes are hydrolyzed in a hydrolysis acidogenic reactor, and a mixture obtained after hydrolysis is acidified to generate a large number of organic acid products with low molecular weight; the bottom of the hydrolysis acidogenic reactor is communicated with the bottom of a methanogenic reactor through a circulation pump and a pipeline; the top of the methanogenic reactor is communicated with the top of the hydrolysis acidogenic reactor; and the acetic acid producing reaction is carried out in the methanogenic reactor and the methane producing reaction is continuously carried out. The invention can separate the hydrolysis acidogenic process from the acetic acid and methane producing process in the anaerobic digestion process so as to prevent organic acids generated by the perishable organic wastes from inhibiting methanogenesis. The device has simple processing procedure, low cost, easy maintenance and stable and reliable performance, is suitable for anaerobic digestion treatment of various perishable organic wastes, and has highly efficient and stable biogas production capacity of the perishable organic wastes through the anaerobic digestion.

Description

Method for producing biogas by anaerobic digestion of high-solid two-phase three-stage perishable organic waste

technical field

The invention relates to a method for treating organic garbage, more specifically, the invention relates to a method for producing biogas by high-solid two-phase three-stage anaerobic digestion using perishable organic garbage as raw materials.

technical background

Perishable organic waste mainly refers to perishable and biodegradable waste generated in the process of life and production, including kitchen waste, slops, vegetable, fruit and meat processing waste, etc. Due to the acceleration of urbanization and the improvement of living standards, not only the absolute output of perishable organic waste has increased significantly, but also the proportion of urban domestic waste has also increased significantly. More than 50% of. The biggest feature of perishable organic waste is the high moisture content and organic matter content, the moisture content is generally above 70%, and the organic matter content is generally above 90% on a dry basis. The above characteristics lead to some problems in the current major municipal solid waste treatment technologies. For example, the high organic matter content leads to the production of a large amount of leachate that can pollute groundwater and the pedosphere during the landfill process, as well as the disorderly emission of greenhouse gas methane; and The higher moisture content leads to the need to add a large amount of additional auxiliary fuel during incineration. In fact, today's sanitary landfill has high requirements for site selection and occupies a large area. In many large cities, it is difficult to find a suitable site for sanitary landfill; for incineration, due to secondary pollution and other problems, At present, the government and the public are also cautious about incineration. Therefore, there is an urgent need to develop a new treatment method without secondary pollution and with a small footprint. Effective treatment of perishable organic waste can make a great contribution to municipal solid waste treatment. The characteristics of high moisture content and high organic matter content make perishable organic waste more suitable for anaerobic digestion, and clean and renewable energy (biogas) can be obtained while processing waste.

The methanogenic process of anaerobic digestion of organic matter includes 4 steps: extracellular hydrolysis, acidogenesis, acetogenicity and methanogenesis. The extracellular hydrolysis step refers to the hydrolysis of polysaccharides, starch, dietary fiber, proteins and lipids into monosaccharides, amino acids, glycerol and long-chain Fatty acid; the acid production step refers to the decomposition of small molecular compounds produced by hydrolysis into simpler acetic acid, propionic acid, butyric acid, pyruvic acid, lactic acid, valeric acid, ethanol and a small amount of carbon dioxide and hydrogen under the action of acid-producing bacteria; The step refers to the process in which the organic acid products (except acetic acid) of the acidogenic step are further converted into acetic acid, carbon dioxide and hydrogen; the methanogenic step refers to the process in which acetic acid is generated by acetic acid-forming methanogens and carbon dioxide and hydrogen to generate methane. An efficient and stable anaerobic digestion methanogenesis process needs to ensure the balance between the hydrolysis acid production process and the acetogenic methanogenesis process. The small molecule organic acids produced in the hydrolysis acid production process can be used by the methanogenesis process in time to avoid the accumulation of organic acids and thus inhibit The microorganisms in the fermentation system, especially the inhibition of methanogens, because methanogens have a low tolerance to organic acids, and when the concentration of organic acids accumulates to 13000mg/L, the methanogenic activity will be completely inhibited.

The main components of perishable organic waste are polysaccharides, starch, dietary fiber, and protein. They are substances that are easily hydrolyzed and acidified. The rate-limiting step of the digestion process leads to organic acid inhibition when perishable organic waste is subjected to anaerobic digestion. In order to avoid organic acid inhibition, traditional single-phase anaerobic digestion can only be completed at a low concentration of fermentation raw materials (less than 4%), and for perishable organic waste such as kitchen waste, its total solid content Generally 15%~25%. At this time, not only a large amount of water needs to be consumed to reduce the concentration of raw materials, but also the lower concentration of raw materials greatly reduces the efficiency of anaerobic digestion of perishable organic waste and the ability to produce biogas. Therefore, the development of non-inhibition and efficient anaerobic digestion biogas production process has become the key to the reduction and energy treatment of perishable organic waste.

Contents of the invention

The main purpose of the present invention is to overcome the deficiencies in the prior art and provide a method for producing biogas by high-solid two-phase three-stage anaerobic digestion using perishable organic waste as raw material, so as to improve the stability and processing efficiency of anaerobic digestion and biogas production capacity.

In order to solve the above technical problems, the present invention is achieved through the following technical solutions:

The technological process of the inventive method comprises the following steps:

(1) Hydrolyzing perishable organic waste in a hydrolysis acid production reactor to generate soluble sugars, amino acids, long-chain fatty acids and glycerin; and acidifying the mixture obtained after the above hydrolysis to generate a large amount of small molecule organic acid products; The hydrolysis acid generation reactor adopts a solid percolation bed, and the perishable organic waste is filled on the percolation packing of the percolation bed, and the water from the sprinkler sprays the perishable organic waste, and at the same time, the perishable organic waste is hydrolyzed to generate acid. The organic acid is dissolved in water, and the leachate is formed through the percolation filler and the porous plate, and is stored at the bottom of the hydrolysis acid production reactor;

Preferred process condition is in the step (1):

Hydrolyze perishable organic waste under the conditions of raw material solid concentration of 15%~40%, temperature of 25°C~60°C, and pH value of 4.5~6.5 to produce soluble sugars, amino acids, long-chain fatty acids and glycerol;

The mixture obtained after the above hydrolysis is acidified at a temperature of 25°C~60°C and a pH value of 4.5~6.5 to generate a large number of small molecule organic acid products, including pyruvic acid, acetic acid, propionic acid, butyric acid, valeric acid, lactic acid, ethanol, and small amounts of hydrogen and carbon dioxide.

(2) The bottom of the hydrolysis acid production reactor is connected with the bottom of the methanation reactor through a circulating pump and a pipeline; the top of the methanation reactor is connected with the top of the hydrolysis acid production reactor; in the production of the methanation reactor, the acetogenic reaction is carried out, and the step ( 1) The organic acid products produced by acidification except acetic acid generate acetic acid, hydrogen and carbon dioxide under the action of acetogenic bacteria; and continue the methanogenic reaction, and ferment acetic acid under the action of acetic acid-trophic methanogenic bacteria to generate methane and carbon dioxide , ferment hydrogen and carbon dioxide under the action of hydrogenotrophic methanogens to generate methane; the main body of the methanogen reactor is the upper fiber packed bed reactor, and the fiber filler can attach acetogenic bacteria and methanogenic bacteria to improve the methanogenic reaction The concentration of acetogenic bacteria and methanogenic bacteria in the reactor, thereby improving the performance of biogas production; the bottom of the methanogenic reactor is provided with a filter bed, which is used to intercept the particulate organic matter in the leachate and avoid blocking the fiber packing bed; the biogas produced in step (1) While the leachate flows through the methanogenic reactor, the organic acids in the leachate generate methane and carbon dioxide under the successive action of acetogenic bacteria and methanogenic bacteria;

The preferred process condition of step (2) is:

The organic acid products except acetic acid produced in the acidification step (1) are generated under the action of acetogenic bacteria to generate acetic acid, hydrogen and carbon dioxide, and the temperature of the reaction is controlled at 25° C. to 60° C., and the pH value is 6.5 to 8.0.

The obtained acetic acid is fermented under the action of acetic acidotrophic methanogens to produce methane and carbon dioxide. The hydrogen and carbon dioxide in the previous step are fermented under the action of hydrogenotrophic methanogens to produce methane. The two types of methanogens participate in the methanogenic The reaction temperature is controlled at 25°C~60°C, and the pH value is 6.5~8.0.

(3) Regularly remove some perishable organic waste hydrolysis residues from the discharge port of the hydrolysis acid production reactor to increase the effective treatment volume of the reactor; regularly remove perishable organic waste seepage from the slag discharge port of the hydrolysis acid production reactor Filtrate sediment to increase the effective storage volume of leachate; regularly clean and refill the filter packing in the filter bed in the methanogenic reactor to ensure good filtering effect.

The general cleaning time is as follows:

Remove some perishable organic waste hydrolysis residues from the discharge port of the hydrolysis acid production reactor every 10 days to 60 days to increase the effective treatment volume of the reactor; Remove perishable organic landfill leachate sediments at the slag port to increase the effective storage volume of leachate; clean and refill the filter packing in the filter bed of the methanogenic reactor every 30 days to 90 days to ensure good filtering effect.

A further improvement of the present invention is:

The bottom of the hydrolysis acid production reactor and the bottom of the methanation reactor are connected by a circulation pump and a pipeline. The inlet section of the circulation pump is provided with a branch pipeline for adding anaerobic digestion inoculum, acid-base regulator and water to the methanation reactor. wait. When the operation of the methanogenic reactor is abnormal, specifically, when the methanogenic reactor is slightly overacidic or overalkaline, it can be adjusted by controlling the circulation of the leachate; when the methanogenic reactor is severely overacidic or When it is too alkaline, a pH regulator can be pumped from the branch pipeline at the inlet section of the circulation pump to adjust the pH.

Compared with prior art, the beneficial effect of the present invention is:

The invention can separate the hydrolysis acid production process (hydrolysis acid production phase) and the acetogenic methanation process (methanogenic phase) of the anaerobic digestion process, and avoid the organic acid produced by perishable organic garbage from inhibiting the methanogenic effect. The hydrolysis acid production phase uses a high solid percolation bed reactor, which can ferment perishable organic waste at a higher raw material concentration, and the raw material concentration can reach up to 40%. Therefore, there is no need to add a large amount of water to reduce the raw material concentration. In addition, the water used for showering perishable organic waste in the solid percolation bed reactor comes from the methanogenic reactor, and the water in the whole system can realize self-circulation. Therefore, the invention is a water-saving perishable Anaerobic digestion of organic waste to generate biogas treatment device. The filler in the fiber packing bed in the methanogenic reactor can attach methanogenic bacteria to increase the cell concentration of methanogenic bacteria in the reactor, thereby improving the biogas production capacity of anaerobic digestion. Before the leachate enters the fiber packing bed, the setting of the filter bed can effectively intercept the particulate organic matter in the leachate to avoid clogging the fiber packing bed. The filter packing inlet and outlet are set on the filter bed, and the filter packing can be cleaned and refilled regularly to ensure a good filtering effect. Compared with the traditional single-phase anaerobic digestion device for perishable organic waste, the device of the invention can significantly increase the treatment concentration of perishable organic waste anaerobic digestion, the highest can be increased from 4% to 40%, and the pool capacity can produce biogas The maximum rate can be increased from 0.8m ³ /(m ³ ·d) to 2.5m ³ /(m ³ ·d), and it can effectively avoid the inhibition of organic acid on methanogenesis.

The process operation and management of the method of the invention are simple, and the anaerobic digestion biogas production performance is stable and reliable. It is suitable for anaerobic digestion treatment of various perishable organic wastes. It can not only efficiently treat organic wastes, reduce its serious pollution to the environment, but also produce clean and renewable energy (biogas), which can realize the energy utilization of organic wastes. Thereby turning waste into treasure.

The invention has efficient and stable perishable organic waste anaerobic digestion biogas production capacity, is very suitable for application and promotion in kitchen waste treatment plants, slop treatment centers, fruit, vegetable and meat processing plants, etc., and has good economic and environmental advantages and social benefits.

Description of drawings

Fig. 1 is a flow chart of the method of the present invention.

Reference signs: feed hopper 1, hydrolysis acid production reactor 2, methane production reactor 3, circulation pump 4, water distributor 5, spray head 6, feed inlet 7, perforated plate 8, discharge outlet 9, Slag outlet 10, filter packing 11, filter bed 12, fiber packing bed 13, filter packing 14, fiber packing frame 15, fiber packing 16, filter packing inlet 17, filter packing outlet 18, gas discharge port 19, safety valve 20 , pressure gauge 21, and gas discharge port are respectively provided with a flow meter 22, a warming jacket 23, an insulation layer 24, a temperature/acidity meter 25, a sampling port 26, and a branch pipeline 27.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

The main components of perishable organic waste are polysaccharides, starch, dietary fiber, protein, and lipids. The anaerobic digestion of such raw materials to produce methanogenesis includes four steps: extracellular hydrolysis, acid production, acetogenic production, and methanogenesis. The extracellular hydrolysis step refers to the hydrolysis of polysaccharides, starch, dietary fiber, proteins and lipids into monosaccharides, amino acids, glycerol and long-chain Fatty acid; the acid production step refers to the decomposition of small molecular compounds produced by hydrolysis into simpler acetic acid, propionic acid, butyric acid, pyruvic acid, lactic acid, valeric acid, ethanol and a small amount of carbon dioxide and hydrogen under the action of acid-producing bacteria; The step refers to the process in which the organic acid products (except acetic acid) of the acidogenic step are further converted into acetic acid, carbon dioxide and hydrogen; the methanogenic step refers to the process in which acetic acid is generated by acetic acid-forming methanogens and carbon dioxide and hydrogen to generate methane.

The types of microorganisms involved in the above-mentioned whole process include hydrolytic acid producing bacteria, acetogenic bacteria and methanogenic bacteria, among which hydrolytic acid producing bacteria can secrete extracellular hydrolytic enzymes to hydrolyze raw materials, and ferment the hydrolyzate to produce organic acids, and methanogenic bacteria include acetic acid trophic methanogens and hydrogenotrophic methanogens. Anaerobic activated sludge from biogas digesters or municipal sewage treatment plants generally contains the above-mentioned types of microorganisms, so this type of anaerobic activated sludge is usually used as an inoculum for anaerobic digestion of biogas. However, the physiological characteristics of hydrolytic acid producing bacteria and methanogenic bacteria are different. The pH value range allowed for the growth and metabolism of hydrolytic acid producing bacteria is relatively wide, ranging from 4.5 to 9.0, and the growth rate of the bacteria is relatively fast, and its generation time is generally 10~ 30 minutes; while the pH range allowed for the growth and metabolism of methanogens is narrow, 6.5-8.0, and the growth rate is slow, and the generation time is generally 4-6 days. In view of the above characteristics, the present invention completes the acid production process and the methane production process of perishable organic waste in two reactors respectively, and controls the operating pH of the two reactors separately, on the one hand avoids the generation of acid by hydrolysis High concentration of organic acid inhibits methanogens, and on the other hand facilitates the independent optimal control of the two processes. At the same time, the fiber packing bed is used as the methanogenic reactor, and the concentration of these two types of bacteria in the methanogenic reactor is increased through the adsorption of the fiber packing on the acetogenic bacteria and methanogenic bacteria, thereby improving the biogas production performance of anaerobic digestion.

The operation process of technology in the present embodiment is as follows:

The device used in this embodiment is shown in Figure 1. When starting, add a small amount of perishable organic waste from the feed hopper 1 to the hydrolysis acid production reactor 2, and pump the inoculum from the branch pipeline 27 of the inlet section of the circulation pump 4. For the methanogenic reactor 3, after the inoculum is submerged in the fiber filler, continue to pump the inoculum until perishable organic waste leachate is formed at the bottom of the hydrolysis acid production reactor 2, and when the leachate height is close to the porous plate 8, close the branch pipe The valve of road 27 stops pumping inoculation solution, so far completes the addition of inoculation solution. Subsequently, the leachate is pumped into the methanogenic reactor 3 from the bottom of the hydrolysis acid production reactor 2 through the circulation pump 4, and the liquid in the methanation reactor 3 overflows from the top of the fiber packing bed 13 to the hydrolysis acid production reactor 2 , and spray the perishable organic waste with the help of the water distributor 5 and the spray head 6, the liquid that is sprayed down dissolves the organic acid produced in the process of hydrolyzing the perishable organic waste to produce acid, and flows through the percolation filler 11 and The perforated plate 8 forms leachate and stores it at the bottom of the hydrolysis acid generation reactor 2, thus completing a liquid cycle. Acclimatization of the methanogens and their attachment and growth on the fibrous filler 16 are accomplished through a number of such cycles. After the domestication is completed, the perishable organic waste is gradually added until the filling height of the perishable organic waste is close to the position of the feed inlet 7 . While gradually adding perishable organic waste, increase the number of liquid circulation until continuous circulation, and finally realize the continuous normal operation of the device of the invention.

The inoculum is anaerobic activated sludge from biogas digesters or municipal sewage treatment plants.

Example 1

(1) Add a small amount of kitchen waste from the feed hopper 1 to the hydrolysis acid production reactor 2, and control the temperature of the hydrolysis acid production reactor 2 at 37°C.

(2) Collect the anaerobic activated sludge in the digester, pump it into the methane reactor 3 through the branch pipeline 27, after the anaerobic activated sludge submerges the fiber filler 16, continue to pump the anaerobic activated sludge until it is hydrolyzed Kitchen waste leachate is formed at the bottom of the acid-generating reactor 2, and when the leachate height is close to the porous plate 8, the valve of the branch pipeline 27 is closed to stop pumping the anaerobic activated sludge. 37°C.

(3) In the hydrolysis acid production reactor in the above process, the kitchen waste is hydrolyzed in the anaerobic activated sludge to generate acetic acid, propionic acid, butyric acid, valeric acid, pyruvic acid, lactic acid, ethanol and a small amount of Carbon dioxide and hydrogen, wherein carbon dioxide and hydrogen are discharged from the exhaust port 19 at the top of the hydrolysis acid production reactor 2, and the organic acid is dissolved in the leachate. The control temperature of hydrolysis and acid generation is 37°C and pH is 5.5.

(4) The above-mentioned leachate is pumped into the methanogenic reactor 3 through the circulation pump 4, and in the methanogenic reactor 3, the organic acid in the leachate generates methane and carbon dioxide under the successive actions of the acetogenic bacteria and the methanogenic bacteria, Methane and carbon dioxide are discharged from the exhaust port at the top of the methanogenic reactor 3 , and the leachate after the organic acid is utilized flows from the overflow port at the top of the methanogenic reactor 3 to the hydrolysis acid production reactor 2 . The control temperature for acetogenic and methanogenesis is 37°C, and the pH is 7.2.

The acetogenic and methanogenic reactions are carried out in the methanogenic reactor 3, and the methanogenic reactor 3 is divided into a filter bed 12 and a fiber packing bed 13 from bottom to top, and the filter bed 12 retains particulate organic matter in the leachate to avoid clogging the fiber packing bed 13. The fiber packing 16 in the fiber packing bed 13 can attach acetogenic bacteria and methanogenic bacteria, increase the concentration of these two types of bacteria in the methanogenic reactor 3, thereby improving the performance of anaerobic digestion for biogas production.

(5) The domestication of the methanogenic bacteria in the methanogenic reactor 3 and their attachment and growth on the fibrous filler 16 were completed after 10 days of repeated leachate circulation. During this process, the temperature of the hydrolysis acid production reactor 2 is controlled to be 37° C., and the pH is 5.5; the temperature of the methanation reactor 3 is controlled to be 37° C., and the pH is 7.2.

(6) After the domestication is completed, add kitchen waste gradually until the filling height of the kitchen waste is close to the position of the feed port 7 of the hydrolysis acid generation reactor 2 . While gradually adding kitchen waste, increase the number of leachate circulation until continuous circulation, and finally realize the continuous normal operation of the process. During this process, the temperature of the hydrolysis acid production reactor 2 is controlled to be 37° C., and the pH is 5.5; the temperature of the methanation reactor 3 is controlled to be 37° C., and the pH is 7.2.

(7) After normal operation, remove part of the hydrolysis residue of kitchen waste from the discharge port 9 of the hydrolysis acid generation reactor 2 every 30 days.

(8) After normal operation, every 50 days, remove the kitchen waste leachate sediment from the slag outlet 10 of the hydrolysis acid production reactor 2; every 50 days, discharge the filter packing from the filter packing outlet 18 of the filter bed 12 14 for cleaning and refilling from filter packing inlet 17.

Example 2

The steps of this embodiment are the same as in Example 1, wherein the processing raw material is meat processing waste, and

In the step (2), the temperature of the control methanogenic reactor 3 is 25° C.; in the step (3), the hydrolysis acid production control pH is 6.5; 8.0; in the step (5), through 20 days of repeated leachate circulation, the temperature of the control hydrolysis acid production reactor 2 is 25 ℃, and the pH is 6.5; the temperature of the methanogenic reactor is 25 ℃, and the pH is 8.0; the step In (6), the temperature of the hydrolysis acid production reactor is controlled to be 25°C, the pH is 6.5, the temperature of the methane production reactor is 25°C, and the pH is 8.0; in step (7), part of the meat processing waste is removed every 40 days for hydrolysis residue; every 60 days in step (8), remove the leachate sediment; every 60 days, clean and refill the filter filler 14 in the filter bed 12 .

Example 3

The steps of this embodiment are the same as in embodiment 1, wherein the processing raw material is vegetable processing waste, and

In the step (1), the temperature of the hydrolysis acid generation reactor 2 is controlled to be 60° C.; the temperature of the methane production reactor 3 is controlled to be 60° C. in the step (2); the hydrolysis acid generation control temperature of the step (3) is 60° C. The pH is 4.5; in the step (4), the control temperature of acetic acid and methane production is 60 ℃, and the pH is 6.5; in the step (5), the temperature of the hydrolysis acid production reactor 2 is controlled through multiple leachate circulations of 15 days. 60 DEG C, the pH is 4.5; the temperature of the methanogenic reactor 3 is 60 DEG C, and the pH is 6.5; the temperature of the controlled hydrolysis acid production reactor 2 in step (6) is 60 DEG C, and the pH is 4.5; The temperature is 60°C and the pH is 6.5; in step (7), remove part of the vegetable processing waste hydrolysis residue every 20 days; in step (8), remove the leachate sediment every 40 days; every 40 days, clean and re- The filter packing 14 in the filter bed 12 is filled.

Compared with the traditional single-phase anaerobic digestion biogas production method of perishable organic waste with low solid concentration, the present invention can process perishable organic waste under the condition that the raw material solid concentration is as high as 40%, and the hydrolysis of the anaerobic digestion process The acid production process (hydrolysis acid production phase) is separated from the acetogenic and methanogenic process (methanogenic phase), and two stages are set in the methanogenic phase, namely the filter bed and the fiber packing bed. This high-solid two-phase three-stage anaerobic digestion The biogas production process is an efficient and stable energy treatment method for perishable organic waste. Adopting the invention can significantly increase the treatment concentration of anaerobic digestion of perishable organic waste, can increase the raw material solid concentration from 4% to 40% at the highest, and can increase the biogas production rate of the tank capacity from 0.8m ³ /(m ³ ·d at the highest) ) to 2.5m ³ /(m ³ ·d), and can effectively avoid the inhibition of organic acids on methanogenesis.

Finally, it should also be noted that the above examples are only specific implementation examples of the present invention. Obviously, the present invention is not limited to the above embodiments, and many variations are possible. All deformations that can be directly derived or associated by those skilled in the art from the content disclosed in the present invention should be considered as the protection scope of the present invention.

Claims (4)

1. A method for producing biogas by high-solid two-phase three-stage anaerobic digestion of perishable organic waste, characterized in that it comprises the following steps: (1) Hydrolyzing perishable organic waste in a hydrolysis acid production reactor to generate soluble sugars, amino acids, long-chain fatty acids and glycerin; and acidifying the mixture obtained after the above hydrolysis to generate a large amount of small molecule organic acid products; The hydrolysis acid generation reactor adopts a solid percolation bed, and the perishable organic waste is filled on the percolation packing of the percolation bed, and the water from the sprinkler sprays the perishable organic waste, and at the same time, the perishable organic waste is hydrolyzed to generate acid. The organic acid is dissolved in water, and the leachate is formed through the percolation filler and the porous plate, and is stored at the bottom of the hydrolysis acid production reactor; (2) The bottom of the hydrolysis acid production reactor is connected with the bottom of the methanation reactor through a circulating pump and a pipeline; the top of the methanation reactor is connected with the top of the hydrolysis acid production reactor; in the production of the methanation reactor, the acetogenic reaction is carried out, and the step ( 1) The organic acid products produced by acidification except acetic acid generate acetic acid, hydrogen and carbon dioxide under the action of acetogenic bacteria; and continue the methanogenic reaction, and ferment acetic acid under the action of acetic acid-trophic methanogenic bacteria to generate methane and carbon dioxide , ferment hydrogen and carbon dioxide under the action of hydrogenotrophic methanogens to generate methane; the main body of the methanogen reactor is the upper fiber packed bed reactor, and the fiber filler can attach acetogenic bacteria and methanogenic bacteria to improve the methanogenic reaction The concentration of acetogenic bacteria and methanogenic bacteria in the reactor, thereby improving the performance of biogas production; the bottom of the methanogenic reactor is provided with a filter bed, which is used to intercept the particulate organic matter in the leachate and avoid blocking the fiber packing bed; the biogas produced in step (1) While the leachate flows through the methanogenic reactor, the organic acids in the leachate generate methane and carbon dioxide under the successive action of acetogenic bacteria and methanogenic bacteria; (3) Regularly remove some perishable organic waste hydrolysis residues from the discharge port of the hydrolysis acid production reactor to increase the effective treatment volume of the reactor; regularly remove perishable organic waste seepage from the slag discharge port of the hydrolysis acid production reactor Filtrate sediment to increase the effective storage volume of leachate; regularly clean and refill the filter packing in the filter bed in the methanogenic reactor to ensure good filtering effect. 2. The method for producing biogas by high-solid two-phase three-stage anaerobic digestion of perishable organic waste as claimed in claim 1, further comprising the steps of: setting a branch pipeline at the inlet section of the circulation pump; When the reactor is slightly overacid or overalkaline, it is adjusted by controlling the circulation of leachate; when the methanogenic reactor is severely overacid or overalkaline, the pH regulator is pumped from the branch pipeline of the inlet section of the circulation pump to adjust pH. 3. the method for producing biogas by high-solid two-phase three-stage anaerobic digestion of perishable organic waste as claimed in claim 1, characterized in that in the step (1), the perishable organic waste is prepared at a raw material solid concentration of 15% ~40%, temperature 25℃~60℃, pH value 4.5~6.5 under the conditions of hydrolysis to produce soluble sugars, amino acids, long-chain fatty acids and glycerin; the mixture obtained after the above hydrolysis at a temperature of 25℃~60℃ Acidification under the condition of pH 4.5~6.5 produces a large number of small molecular organic acid products, including pyruvic acid, acetic acid, propionic acid, butyric acid, valeric acid, lactic acid, ethanol, and a small amount of hydrogen and carbon dioxide. 4. the method for producing biogas by high-solid two-phase three-stage anaerobic digestion of perishable organic waste as claimed in claim 1, is characterized in that in the step (2), the acidification of the step (1) is produced except for acetic acid The organic acid product generates acetic acid, hydrogen and carbon dioxide under the action of acetogenic bacteria. The temperature of the reaction is controlled at 25°C~60°C and the pH value is 6.5~8.0; Carbon dioxide, hydrogen and carbon dioxide in the previous step are fermented into methane under the action of hydrogenotrophic methanogens. The methanogenic reaction of these two types of methanogens is controlled at a temperature of 25°C~60°C and a pH value of 6.5~8.0 .

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