CN112625873A - Two-phase dry anaerobic digestion fermentation system - Google Patents

Abstract

The invention is suitable for the technical field of biogas fermentation, and provides a two-phase dry anaerobic digestion fermentation system, which comprises: a hydrolysis acidification pool, a methanation pool, a compost reactor and a heat exchange device. Compared with the prior art, the invention combines the biogas fermentation technology with the composting technology, utilizes the heat generated in the composting process to provide the heat required by biogas fermentation for the hydrolysis acidification tank and the methanation tank, and does not need other additional heating facilities such as an electrothermal film, a biogas boiler and the like; secondly, biogas residues generated in the methanation tank can be used as a raw material of aerobic compost for subsequent production of organic fertilizer; and thirdly, in the whole reaction system, the digestion raw materials automatically flow by means of self weight and pressure difference, and an additional feeding and discharging device is not needed. The invention greatly reduces the cost of methane fermentation, basically has no discharge of wastes such as methane slag, slag liquid and the like, and is convenient for popularization and application of the methane production technology in villages and small towns.

Description

Two-phase dry anaerobic digestion fermentation system

Technical Field

The invention belongs to the technical field of biogas fermentation, and particularly relates to a two-phase dry anaerobic digestion fermentation system.

Background

The biogas anaerobic fermentation can convert various cultivation wastes and plant wastes into biogas at low cost. The methane content in the biogas is generally 60%, and the balance is mainly carbon dioxide. After carbon dioxide is removed, the artificial natural gas with the methane content of 90 percent can be obtained. It can be seen that this is an energy development path that nature indicates for humans. With the improvement of the rural living standard in China, the treatment of domestic garbage, toilet excrement and agricultural and forestry organic solid wastes becomes an urgent task for improving the living environment of rural areas in China and building beautiful and livable villages in China. The dry anaerobic fermentation technology is adopted to realize reduction and resource utilization of domestic garbage, toilet excrement and organic garbage in villages and towns, is a new way for improving the living environment of rural areas in China and building beautiful and livable villages, and is a technical problem which needs to be solved for multisource organic garbage treatment in villages and towns in China at present.

In order to improve the production capacity of the methane tank, dry fermentation technology of medium-temperature or high-temperature fermentation is often adopted at present. The dry anaerobic fermentation has high and stable gas production amount and wide material adaptability, and the livestock and poultry manure, the agricultural and forestry wastes and the kitchen waste can be used as digestion materials; meanwhile, no biogas slurry is discharged in the whole fermentation process, so that secondary pollution is avoided. However, dry fermentation technology often requires medium and high temperature, when the temperature is lower than 10 ℃, the activity of zymophyte in biogas slurry is inhibited, and the capability of biogas generation of the biogas digester is very weak. Therefore, in the medium-high temperature dry fermentation technology, the heating and heat preservation of the methane tank are key problems which need to be solved, and extra energy consumption is needed for heat preservation and temperature preservation. At present, the heat preservation technical method and measures for the methane tank mainly comprise methods of covering an electric heating film, assisting heat of a methane boiler, solar heating and the like.

The applicant of the present invention finds that, in implementing the above technical solution, the above technical solution has at least the following disadvantages:

the conventional biogas fermentation technology is greatly influenced by climate change, and adopts external energy to supplement and heat the biogas digester, so that the early investment is large, the operation and maintenance cost is high, and the large-scale application and popularization in villages and small towns are difficult.

Disclosure of Invention

An object of an embodiment of the present invention is to provide a two-phase dry anaerobic digestion fermentation system, which aims to solve the problems mentioned in the background art.

The embodiment of the invention is realized by a two-phase dry anaerobic digestion fermentation system, which comprises:

a hydrolysis acidification pool; the hydrolysis acidification tank is internally provided with hydrolysis acidification bacteria for performing hydrolysis acidification treatment on the materials;

a methanation tank; the methanation pool is provided with methanogens; the methanation tank is communicated with the hydrolysis acidification tank, and the digestion raw materials subjected to hydrolysis acidification automatically flow into the methanation tank through self weight and pressure difference and are decomposed into biogas slurry, biogas residues and biogas by methanogens;

the composting reactor is used for composting the mixture of the biogas residues and the biogas slurry generated by the methanation tank and the specified raw materials, and heat energy generated in the composting process is supplied to the heat exchange device;

a heat exchange device; the heat exchange device utilizes the heat energy supplied by the composting reactor to keep the hydrolysis acidification tank and the methanation tank at preset temperature.

Preferably, biogas slurry with a preset proportion is added into the material entering the hydrolysis acidification tank; and transferring the sediments and the scum generated in the hydrolysis acidification tank and the biogas residues generated in the methanation tank to the composting reactor for composting.

Preferably, the heat energy source of the heat exchange device further comprises a biogas boiler, solar energy or electric energy.

Preferably, the heat exchange device comprises:

the heat exchanger is used for acquiring heat energy generated in the composting process of the composting reactor;

a first medium circulation vessel in communication with the heat exchanger; supplying the medium of a first temperature value generated in the heat exchanger to the first medium circulation vessel;

a second medium circulation vessel in communication with the heat exchanger; the medium with the second temperature value in the second medium circulation container is supplied to the heat exchanger; the first temperature value is greater than the second temperature value;

the first jacket is arranged on the outer surface of the hydrolysis acidification tank; the first jacket is communicated with a first medium circulation container and a second medium circulation container;

the heat exchange coil is arranged inside the hydrolysis acidification tank; the heat exchange coil is communicated with the first medium circulation container and the second medium circulation container;

the second jacket is arranged on the outer surface of the methanation tank; the second jacket is in communication with the first medium circulation vessel and the second medium circulation vessel.

Preferably, the heat exchange mode of the heat exchanger is dividing wall type heat exchange; the heat exchanger comprises an in-cylinder heat exchanger and an out-cylinder heat exchanger; the heat exchanger in the cylinder comprises a heat exchange coil and a central main pipe heat exchanger with a circulating branch pipe; the central main pipe heat exchanger with the circulating branch pipe comprises a central main pipe and the circulating branch pipe; the central main pipe is of a hollow circular pipe structure, and the circulating branch pipe is of a hollow plate structure.

Preferably, the first medium circulation vessel and the second medium circulation vessel are communicated with the heat exchanger, the first jacket and the second jacket through medium pipelines; the outer surfaces of the composting reactor, the first medium circulating container, the second medium circulating container and the medium pipeline are all provided with heat insulating layers with the thickness not less than 50mm and the heat conductivity not more than 0.04 kJ/(m.h.DEG C).

Preferably, the heat-insulating layer on the outer surface of the composting reactor is a heat-insulating sleeve; the heat-insulating sleeve is a jacket with a sectional and open-close type structure; the distance between the heat-preservation sleeve and the composting reactor is kept between 5 and 10 mm; the heat exchanger and the heat-insulating sleeve do not rotate along with the composting reactor.

Preferably, the first jacket is welded on the outer surface of the hydrolysis acidification tank, and the second jacket is welded on the outer surface of the methanation tank; the lower ends of the first jacket, the second jacket and the heat exchange coil are respectively provided with a medium inlet communicated with the first medium circulation container, and the upper ends of the first jacket, the second jacket and the heat exchange coil are respectively provided with a medium outlet communicated with the second medium circulation container.

Preferably, the medium inlets of the first jacket, the second jacket and the heat exchange coil are provided with self-control valves.

Preferably, the first jacket wraps the outer surface of the hydrolysis acidification tank completely or partially; the second jacket wraps the outer surface of the methanation tank completely or partially.

Preferably, the outer surface of the methanation pool is not provided with a second jacket.

Preferably, the heat exchange coil is formed by coiling a stainless steel hollow water pipe, the spiral distance is 50-500mm, and the spiral diameter is 1/2-2/3 of the diameter or width of the hydrolysis acidification tank.

Preferably, the composting reactor adopts a sealed reaction bin in a rotary kiln structure; the sealed reaction bin comprises:

a bin body;

and the driving piece is used for driving the bin body to rotate.

Preferably, the composting reactor is arranged in an inclined manner relative to the horizontal plane, and the inclination angle is 0.1-1 degrees.

Preferably, the hydrolysis acidification tank is of a horizontal structure; the hydrolysis acidification tank is obliquely arranged underground, and the inclination angle of the hydrolysis acidification tank relative to the horizontal plane is 0.01-1 degrees.

Preferably, the hydrolysis acidification tank is a long cylinder or a U-shaped groove.

Preferably, the hydrolysis acidification tank is formed by welding stainless steel plates or enameled steel plates.

Preferably, the hydraulic retention time of the hydrolysis acidification tank is 4-8 days.

Preferably, the hydrolysis acidification tank is provided with:

a material inlet and a gas outlet;

the first stirring device is used for stirring materials;

a digestive juice discharge port for discharging digestive juice, a sediment discharge port for discharging sediment and a scum discharge port for discharging scum;

and one or more of at least the following detection devices, the detection devices comprising:

the first temperature detection device is used for detecting the temperature in the hydrolysis acidification tank;

the first pressure detection device is used for detecting the pressure in the hydrolysis acidification tank;

the first pH detection device is used for detecting the pH value of the material in the hydrolysis acidification tank;

the first ORP detection device is used for detecting the ORP value of the materials in the hydrolytic acidification tank;

and the first liquid level detection device is used for detecting the height of the material in the hydrolysis acidification tank.

Preferably, the hydrolysis acidification tank is further provided with a first high-pressure protection device, a first manhole and a first observation hole.

Preferably, the first stirring shaft of the first stirring device is transversely or longitudinally arranged; the length of the first stirring blade of the first stirring device does not exceed 1/2 of the diameter or the width of the hydrolytic acidification tank; the hydrolysis acidification tank is regularly stirred for 3-4 times every day, and each stirring time is 5-20 min.

Preferably, a plurality of first baffle plates are arranged in the hydrolysis acidification tank; the height of the first baffle plate is not more than that of the first stirring shaft.

Preferably, the digestive juice discharge port is arranged at 1/2-1/3 of the liquid level height of the digestive juice; the digestion liquid discharge port is communicated with the methanation tank through a siphon pipe; the siphon is a hollow elbow pipe similar to an arch bridge, and the siphon is connected with the hydrolysis acidification tank and the methanation tank in a slipknot mode, such as flange connection, quick joint connection and the like.

Preferably, the sediment discharge port is arranged at the bottom of the hydrolysis acidification tank; the sediment discharge port is connected with the spiral discharging machine through a valve and a pipeline; the static pressure generated by the vertical distance between the top of the discharge pipe of the spiral discharging machine and the liquid level in the hydrolysis acidification tank is 5-10kPa greater than the internal pressure of the hydrolysis acidification tank.

Preferably, the scum outlet is arranged at the liquid level of the digestive juice; the height of the scum discharge port does not exceed the height of the liquid level of the digestive juice by 20-50 mm; the scum discharge port is communicated with the sealed scum pond through a valve and a pipeline.

Preferably, the surfaces of the hydrolysis acidification tank and the methanation tank are provided with second heat-insulating layers.

Preferably, the methanation tank adopts a horizontal structure; the methanation pool is obliquely arranged underground, and the inclination angle of the methanation pool relative to the horizontal plane is 0-0.05 degrees.

Preferably, the methanation tank is a long cylinder or a U-shaped groove.

Preferably, the methanation pool is formed by welding a stainless steel plate or an enamel steel plate.

Preferably, a plurality of second baffle plates are arranged in the methanation pool; the height of the second baffle plate is 1/4-1/2 of the liquid level height of the digestive juice in the methanation pool.

Preferably, the hydraulic retention time of the methanation pool is 15-30 days.

Preferably, the methanation tank is provided with:

a digestive juice inlet, a discharge outlet and a methane outlet;

second stirring means for stirring the mixture;

an acidolysis regulating and dosing device for regulating the pH value in the methanation tank;

and one or more of at least the following detection devices, the detection devices comprising:

the second temperature detection device is used for detecting the temperature in the methanation pool;

the second pressure detection device is used for detecting the pressure in the methanation pool;

the second pH detection device is used for detecting the pH value of the material in the methanation pool;

the second ORP detection device is used for detecting the ORP value of the material in the methanation cell;

and the second liquid level detection device is used for detecting the height of the material in the methanation pool.

Preferably, the discharge hole is communicated with a filter pressing device; the filter pressing device uses plate frame filter pressing or stacked spiral filter pressing.

Preferably, the second stirring device is a mechanical stirring device, a biogas stirring device or a biogas slurry stirring device.

Preferably, the biogas stirring is to pump out biogas above the liquid level of the digestive juice in the methanation tank through a biogas pump and feed the biogas into the methanation tank from the bottom and the lateral lower part of the methanation tank, so as to generate strong gas backflow to drive sinking sludge to float upwards and promote methane gas to smoothly separate from the digestive juice.

Preferably, the biogas stirring requires at least one outlet and three inlets.

Preferably, the biogas slurry stirring is to pump out the biogas slurry from the bottom of the methanation tank through a sludge pump and tangentially spray the biogas slurry from the side upper part (lower than the height of the digestive juice), so that strong circumferential flow is formed inside the methanation tank, and the biogas slurry stirring effect is realized.

Preferably, the biogas slurry stirring needs at least one biogas slurry outlet and two biogas slurry spraying inlets in each set.

Preferably, the biogas stirring and biogas slurry stirring are carried out in a way that one set or more than one set is required to be arranged between each baffle plate and the baffle plate and in the area where the baffle plate and the feeding and discharging ends are isolated.

Preferably, the biogas stirring and the biogas slurry stirring are carried out, and the moving speed of the digestion liquid in the methanation tank is caused to be not more than 0.5m/s in the stirring process.

Preferably, the biogas stirring and the biogas slurry stirring are carried out, wherein the stirring time is 5-10min each time and 3-4 times a day.

Preferably, the biogas stirring and the biogas slurry stirring can be independently arranged or simultaneously arranged.

Preferably, when the hydrolytic acidification bacteria and the methanogen are subjected to moderate anaerobic digestion, the first temperature value is 40-55 ℃, and the second temperature value is 30-35 ℃; when the hydrolytic acidification bacteria and the methanogen are subjected to high-temperature anaerobic digestion, the first temperature value is 65-70 ℃, and the second temperature value is 50-55 ℃.

Preferably, the two-phase anaerobic digestion fermentation system further comprises:

a feed vessel; the feeding container is communicated with the hydrolysis acidification tank through a material pipeline; a gravity automatic control valve is arranged on the material pipeline; and a third stirring device for mixing materials is arranged in the feeding container.

Preferably, the static pressure generated by the difference between the bottom of the feeding container and the liquid level in the hydrolysis acidification tank is not less than 10 kPa.

The embodiment of the invention provides a two-phase dry anaerobic digestion fermentation system, which comprises: a hydrolysis acidification pool; the hydrolysis acidification tank is internally provided with hydrolysis acidification bacteria for performing hydrolysis acidification treatment on the materials; a methanation tank; the methanation pool is provided with methanogens; the methanation tank is communicated with the hydrolysis acidification tank and is used for obtaining digestion liquid in hydrolysis acidification and decomposing the obtained digestion liquid into biogas slurry, biogas residues and methane-containing biogas; the composting reactor is used for carrying out composting treatment on the biogas residues generated in the methanation pool, and heat energy generated in the composting process is supplied to the heat exchange device; a heat exchange device; the heat exchange device utilizes the heat energy supplied by the composting reactor to keep the hydrolysis acidification tank and the methanation tank at preset temperature.

Compared with the prior art, the invention combines the biogas fermentation technology with the composting technology, utilizes the heat generated in the composting process to provide the heat required by biogas fermentation for the hydrolysis acidification tank and the methanation tank, does not need to additionally build other heating facilities such as an electrothermal film, a biogas boiler and the like, and the biogas residue generated in the methanation tank can be used as the raw material of aerobic composting to subsequently produce organic fertilizer, thereby greatly reducing the cost of biogas fermentation, ensuring normal biogas production all the year around and facilitating the popularization and application of the biogas production technology in villages and small towns.

In addition, the embodiment of the invention changes the traditional vertical biogas reactor into a horizontal structure, so that the whole hydrolysis acidification tank and the methanation tank are arranged underground, the size construction of the container is not limited, the construction cost is lower, the dead weight of the fermentation raw materials is effectively utilized, the energy consumption of mechanical stirring is reduced, and the problems of high solid content, poor fluidity and high material feeding and conveying difficulty of dry fermentation materials are solved.

Drawings

FIG. 1 is a schematic structural diagram of a two-phase dry anaerobic digestion fermentation system provided by an embodiment of the present invention;

FIG. 2 is a front view of a hydrolysis acidification tank provided by an embodiment of the present invention;

FIG. 3 is a side view of a hydrolytic acidification tank provided by an embodiment of the invention;

FIG. 4 is a cross-sectional view taken along line A-A of FIG. 2;

FIG. 5 is a cross-sectional view taken along line B-B of FIG. 2;

FIG. 6 is a front view of a methanation cell provided in an embodiment of the present invention;

FIG. 7 is a side view of a methanation cell provided in an embodiment of the present invention;

FIG. 8 is a cross-sectional view taken at C-C of FIG. 6;

fig. 9 is a cross-sectional view taken along line D-D of fig. 6.

In the drawings: 1. a composting reactor; 2. a hydrolysis acidification pool; 3. a methanation tank; 101. a feed vessel; 102. a heat exchanger; 105. a first insulating layer; 115. a first medium circulation vessel; 120. a second medium circulation vessel; 200. a gas outlet; 208. a second insulating layer; 212. a discharge hole of digestive juice; 215. a sediment discharge hole; 218. a first pH detection device interface; 220. a first ORP detection device interface; 225. a first stirring shaft; 228. a first baffle plate; 230. a first manhole; 235. a first temperature detection device interface; 250. a first stirring blade; 240. a material inlet; 242. a material pipeline; 250. a first stirring device; 255. a heat exchange coil; 268. a first jacket; 408. an explosion-proof port; 410. a biogas outlet; 415. removing foam; 418. a discharge port; 420. a second pH detection device interface; 421. a second ORP detection device interface; 425. a siphon tube; 428. a medicament inlet; 430. a digestive juice feed port; 438. a second temperature detection device interface; 440. a biogas slurry stirring port; 445. a second baffle plate; 465. a second jacket; 485. a second manhole.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Specific implementations of the present invention are described in detail below with reference to specific embodiments.

Example 1

As shown in fig. 1, a two-phase dry anaerobic digestion fermentation system according to an embodiment of the present invention comprises:

a hydrolysis acidification pool 2; the hydrolysis acidification pool 2 is internally provided with hydrolysis acidification bacteria for performing hydrolysis acidification treatment on the materials;

a methanation tank 3; methanogens are arranged in the methanation pool 3; the methanation tank 3 is communicated with the hydrolysis acidification tank 2, and the digestion raw materials subjected to hydrolysis acidification automatically flow into the methanation tank 3 through self weight and pressure difference and are decomposed into biogas slurry, biogas residues and biogas by methanogens;

the composting reactor 1 is used for composting the mixture of the biogas residues and the biogas slurry generated by the methanation tank 3 and the specified raw materials, and the heat energy generated in the composting process is supplied to the heat exchange device;

a heat exchange device; the heat exchange device utilizes the heat energy supplied by the composting reactor 1 to keep the hydrolysis acidification tank 2 and the methanation tank 3 at preset temperature.

In the embodiment of the invention, the material source can be kitchen garbage, agricultural straw, cultivation excrement and the like, the materials are mixed and then placed in the hydrolysis acidification tank 2, is hydrolyzed and acidified into digestion raw materials (including digestion solution, sediment and scum) under the action of hydrolytic acidification bacteria, the generated digestion raw materials enter a methanation tank 3, decomposing into biogas slurry, biogas residue and methane-containing biogas under the action of methanogens, sending the generated biogas residue and part of biogas slurry together with specified raw materials (sediment and scum can also be sent together) into a composting reactor 1 for composting, supplying heat energy generated in the composting process to a hydrolysis acidification tank 2 and a methanation tank 3 through a heat exchange device, the hydrolysis acidification tank 2 and the methanation tank 3 are insulated, so that the hydrolysis acidification bacteria and the methanogens are always kept at high activity, and a large amount of methane can be continuously generated. The specified raw materials can be kitchen waste, agricultural straws, cultivation manure and other organic wastes.

Compared with the prior art, the invention combines the biogas fermentation technology with the composting technology, utilizes the heat generated in the composting process to provide the heat required by biogas fermentation for the hydrolysis acidification tank 2 and the methanation tank 3, does not need to additionally build other heating facilities such as an electrothermal film, a biogas boiler and the like, and the biogas residue generated in the methanation tank 3 can be used as the raw material of aerobic composting to subsequently produce organic fertilizer, thereby greatly reducing the cost of biogas fermentation, ensuring normal biogas production all the year around and facilitating the popularization and application of the biogas production technology in villages and towns.

As a preferred embodiment of the invention, biogas slurry with a predetermined proportion is added into the material entering the hydrolysis acidification tank; and transferring the sediments and the scum generated in the hydrolysis acidification tank and the biogas residues generated in the methanation tank to the composting reactor for composting.

Specifically, the amount of the added biogas slurry is determined according to the solid content of the raw material, and the solid content of the material is generally controlled to be 20-28% after the biogas slurry is added.

As a preferred embodiment of the present invention, the heat energy source of the heat exchange device further includes a biogas boiler, solar energy or electric energy.

In particular, when the construction cost is within the tolerable range, it is also feasible to use a biogas boiler, solar energy or electric energy as the heat energy source of the heat exchange device.

As shown in fig. 1, as a preferred embodiment of the present invention, the heat exchange device includes:

the heat exchanger 102 is used for acquiring heat energy generated in the composting process of the composting reactor 1;

a first medium circulation vessel 115 communicating with the heat exchanger 102; the medium of the first temperature value generated in the heat exchanger 102 is supplied to the first medium circulation vessel 115;

a second medium circulation vessel 120 in communication with the heat exchanger 102; the medium of the second temperature value in the second medium circulation vessel 120 is supplied to the heat exchanger 102; the first temperature value is greater than the second temperature value;

a first jacket 268 disposed on the outer surface of the hydrolysis acidification tank 2; the first jacket 268 communicates with the first medium-circulating vessel 115 and the second medium-circulating vessel 120;

the heat exchange coil 255 is arranged inside the hydrolysis acidification tank 2; the heat exchange coil 255 is in communication with the first media circulation vessel 115 and the second media circulation vessel 120;

a second jacket 465 arranged on the outer surface of the methanation tank 3; the second jacket 465 communicates with the first medium-circulating vessel 115 and the second medium-circulating vessel 120.

Specifically, pumping devices are arranged between the heat exchanger 102 and the first medium circulation container 115, between the first medium circulation container 115 and the first jacket 268, between the first medium circulation container 115 and the second jacket 465, between the first jacket 268 and the second medium circulation container 120, between the second jacket 465 and the second medium circulation container 120, and between the second medium circulation container 120 and the heat exchanger 102, and are used for circulating and conveying the medium. The medium in this embodiment may be gas (various gases such as air, nitrogen, carbon dioxide, etc.) or liquid (various liquids such as water, heavy oil, lubricating oil, heat transfer oil, etc.), and correspondingly, the heat exchanger 102 may be an air heat exchanger 102, a water heat exchanger 102, or an oil heat exchanger 102. For economic reasons, the medium is typically selected to be water and the heat exchanger 102 is selected to be a water heat exchanger 102. In the operation process of the heat exchange device, the heat exchanger 102 obtains heat energy generated in the composting process of the composting reactor 1, the obtained heat energy heats a medium, the heated medium is stored in the first medium circulation container 115 and is pumped to the first jacket 268, the heat exchange coil 255 and the second jacket 465 through a pumping device to provide heat required by biogas fermentation for the hydrolysis acidification tank 2 and the methanation tank 3, the medium with the reduced temperature after the heat is released enters the second medium circulation container 120 and is pumped back to the heat exchanger 102 through the pumping device to be heated again in the heat exchanger 102. The circulation is carried out, so that the temperature in the hydrolysis acidification tank 2 and the methanation tank 3 is always kept in the high-activity temperature range of the hydrolysis acidification bacteria and the methanogens, and the system can normally generate a large amount of methane all the year round.

As a preferred embodiment of the present invention, the heat exchange mode of the heat exchanger 102 is dividing wall type heat exchange; the heat exchanger 102 includes an in-can heat exchanger 102 and an out-of-can heat exchanger 102; the in-cylinder heat exchanger 102 comprises a heat exchange coil 255 and a central main pipe heat exchanger 102 with a circulation branch pipe; the central main pipe heat exchanger 102 with the circulation branch pipes comprises a central main pipe and the circulation branch pipes; the central main pipe is of a hollow circular pipe structure, and the circulating branch pipe is of a hollow plate structure.

As a preferred embodiment of the present invention, the first medium-circulating vessel 115 and the second medium-circulating vessel 120 are communicated with the heat exchanger 102, the first jacket 268 and the second jacket 465 through medium pipes; the outer surfaces of the composting reactor 1, the first medium circulating container 115, the second medium circulating container 120 and the medium pipeline are all provided with a first heat-insulating layer 105 with the thickness not less than 50mm and the heat conductivity not more than 0.04 kJ/(m.h.DEG C).

As a preferred embodiment of the invention, the first heat-insulating layer 105 on the outer surface of the composting reactor 1 is a heat-insulating sleeve; the heat-insulating sleeve is a jacket with a sectional and open-close type structure; the distance between the heat-preservation sleeve and the composting reactor 1 is kept between 5 and 10 mm; the heat exchanger 102 and the heat-insulating sleeve do not rotate with the composting reactor 1.

As a preferred embodiment of the invention, the first jacket 268 is welded on the outer surface of the hydrolysis acidification tank 2, and the second jacket 465 is welded on the outer surface of the methanation tank 3; the lower ends of the first jacket 268, the second jacket 465 and the heat exchange coil 255 are respectively provided with a medium inlet communicated with the first medium circulation container 115, and the upper ends of the first jacket 268, the second jacket 465 and the heat exchange coil 255 are respectively provided with a medium outlet communicated with the second medium circulation container 120.

In a preferred embodiment of the present invention, the medium inlets of the first jacket 268, the second jacket 465 and the heat exchange coil 255 are provided with self-control valves.

Specifically, the first jacket 268 and the second jacket 465 are thin spaces welded on the outer surfaces of the hydrolysis acidification tank 2 and the methanation tank 3, and are provided with water inlets at the lower parts and water outlets at the upper ends (taking water as an example as a medium). Hot water enters from the lower part and flows out from the upper outlet after filling the jacket. The automatic control valve can automatically control the circulation and the stop of the circulating hot water according to the temperature and the industrial control requirements in the hydrolysis acidification tank 2 and the methanation tank 3. And generally speaking, the temperature of the hot water is required to be 5-10 ℃ higher than the reaction temperature of the digestion solution in the methanation pool 3.

As a preferred embodiment of the present invention, the first jacket 268 fully or partially covers the outer surface of the hydrolytic acidification tank 2; the second jacket 465 wraps the whole or part of the outer surface of the methanation pool 3.

As a preferred embodiment of the invention, the external surface of the methanation pool 3 is not provided with a second jacket 465.

As a preferred embodiment of the invention, the heat exchange coil 255 is formed by coiling a stainless steel hollow water pipe, the coiling distance is 50-500mm, and the coiling diameter is 1/2-2/3 of the diameter or width of the hydrolysis acidification tank 2.

As a preferred embodiment of the invention, the composting reactor 1 adopts a sealed reaction bin in the form of a rotary kiln structure; the sealed reaction bin comprises:

a bin body;

and the driving piece is used for driving the bin body to rotate.

Specifically, the driving piece can be a motor, and the composting reactor 1 is driven to rotate by the motor, so that the biogas residues in the composting reactor 1 can be thoroughly decomposed, and the generated heat energy can be fully released and acquired by the heat exchange device.

As a preferred embodiment of the invention, the composting reactor 1 is arranged obliquely relative to the horizontal plane, and the inclination angle is 0.1-1 degrees.

As a preferred embodiment of the present invention, the hydrolysis acidification tank 2 is a horizontal structure; the hydrolysis acidification tank 2 is obliquely arranged underground, and the inclination angle of the hydrolysis acidification tank relative to the horizontal plane is 0.01-1 degrees.

In particular, the limitation of the current biogas production has a problem that the tank capacity of the biogas tank is limited and the volumetric productivity (output value) is too low. At present, most of methane tanks widely used at home and abroad are vertical, the cost is high, the building volume is limited by height, and the methane tank is difficult to be 100 meters high or 100 meters deep. Therefore, only the residence time is reduced in the process, so that the reaction is incomplete, the energy conversion rate is low, and the biogas slurry pollution load is large. The domestic biogas fermentation retention period is generally 10-15 days, and some biogas fermentation retention periods are only 7 days. In Germany, even under the condition of medium-temperature anaerobic fermentation at a higher temperature, the biogas fermentation retention period is generally 28-45 days.

The volume of the biogas is limited, the biogas conversion efficiency is low, the biogas yield is low, and the economic benefit of energy utilization cannot be realized. For example, a 1 cubic meter chemical reactor can produce 1 ton of chemical material per day, and the value is generally more than 15000 yuan. While a 1 cubic meter biogas reactor (normal temperature) can generally produce only 0.7 cubic meter of biogas on average every day, the value is 1.5 yuan, and the volumetric productivity is only one ten thousandth of that of a chemical reactor. To obtain the production value of a 1 cubic meter chemical reactor in one day, the reactor of the methane tank needs 1 ten thousand cubic meters, the current reactor of the methane tank with 1 ten thousand cubic meters is about 1500 ten thousand yuan, but the annual production value is only about 550 ten thousand yuan. The input-output ratio is too low, and the commercial value is low.

The embodiment of the invention is similar to an underground river by horizontally arranging the hydrolysis acidification tank 2 and underground, so the hydrolysis acidification tank is called as a 'underground river type'. And (3) crushing the dry fermentation materials (the solid content is more than 20 percent), extruding the crushed dry fermentation materials into the underground river from an inlet at the upstream of the underground river by virtue of gravity, slowly creeping the crushed dry fermentation materials to the downstream, generating biogas after anaerobic fermentation, and taking the biogas residues out of an outlet at the downstream of the underground river by virtue of gravity or discharging equipment. The embodiment of the invention changes the traditional vertical biogas reactor into a horizontal structure, so that the whole hydrolysis acidification tank 2 is arranged underground, the temperature in the container is less influenced by climate change, simultaneously the key technology of material fluidization continuous feeding and discharging is solved, the problems of difficult pit-type biogas production and slag discharge and the problems of limited tank capacity, high construction cost and large influence of temperature change in the tank in four seasons on the tank of the vertical biogas digester are solved, and a road is paved for large-scale biogas production.

Compared with the prior art, the size construction of the hydrolysis acidification tank 2 is not limited, the construction cost is low, the dead weight of the fermentation raw materials is effectively utilized, the energy consumption of mechanical stirring is reduced, and the problems of high solid content, poor fluidity and high material feeding and conveying difficulty of dry fermentation materials are solved.

As a preferred embodiment of the invention, the hydrolysis acidification tank 2 can adopt various structures (such as a long cylinder, a U-shaped groove and the like) and can prevent aggregate/dead corners.

As a preferred embodiment of the invention, the hydrolysis acidification tank 2 is formed by welding stainless steel plates or enameled steel plates, and when stainless steel materials are adopted, the inner wall of the hydrolysis acidification tank needs to be subjected to anticorrosion treatment.

As a preferred embodiment of the invention, the hydraulic retention time of the hydrolysis acidification tank 2 is 4-8 days.

As shown in fig. 2 to 5, as a preferred embodiment of the present invention, the hydrolysis acidification tank 2 is provided with:

a material inlet 240 and a gas outlet 200;

a first stirring device 250 for stirring the material;

a digestion liquid discharge port 212 for discharging digestion liquid, a sludge discharge port 215 for discharging sludge, and a scum discharge port for discharging scum;

and one or more of at least the following detection devices, the detection devices comprising:

the first temperature detection device is used for detecting the temperature in the hydrolysis acidification tank 2;

the first pressure detection device is used for detecting the pressure in the hydrolysis acidification tank 2;

the first pH detection device is used for detecting the pH value of the material in the hydrolysis acidification tank 2;

a first ORP detection device for detecting an ORP value of the material in the hydrolysis acidification tank 2;

and the first liquid level detection device is used for detecting the height of the material in the hydrolysis acidification tank 2.

Specifically, the hydrolysis acidification tank 2 is provided with a first pH detection device interface, a first ORP detection device interface, and a first temperature detection device interface 235, which are respectively used for installing a first pH detection device, a first ORP detection device, and a first temperature detection device.

As shown in fig. 2 to 5, as a preferred embodiment of the present invention, the hydrolysis acidification tank 2 is further provided with a first high pressure protection device, a first manhole 230 and a first observation hole.

As shown in fig. 2 to 5, as a preferred embodiment of the present invention, the first stirring shaft 225 of the first stirring device 250 is disposed transversely or longitudinally; the length of the first stirring blade 250 of the first stirring device 250 does not exceed 1/2 of the diameter or the width of the hydrolytic acidification tank 2; the hydrolysis acidification tank 2 is regularly stirred for 3-4 times every day, and each stirring time is 5-20 min.

Specifically, the hydrolysis acidification tank 2 adopts mechanical stirring (dry fermentation, high solid content and poor fluidity).

As a preferred embodiment of the present invention, a plurality of first baffle plates 228 are disposed in the hydrolysis acidification tank 2; the height of the first baffle 228 does not exceed the height of the first stirring shaft 225.

Specifically, the inside aspect ratio of the hydrolysis acidification tank 2 is different, and three or more first baffle plates 228 are provided, which intercept sludge and strains, prolong the retention time of the materials, and simultaneously play a role in supporting the first stirring shaft 225.

As a preferred embodiment of the invention, the digestion liquid outlet 212 is arranged at 1/2-1/3 of the height of the digestion liquid level; the digestion liquid discharge port 212 is communicated with the methanation tank 3 through a siphon tube 425; the siphon 425 is a hollow elbow pipe similar to an arch bridge, and the connection between the siphon 425 and the hydrolysis acidification tank 2 and the methanation tank 3 adopts a slipknot mode, such as flange connection, quick joint connection and the like.

Specifically, the digestion liquid discharge port 212 is arranged at the lower middle part of the digestion liquid level and is connected with the methanation tank 3 through a siphon 425, and the acidified digestion liquid automatically flows into the methanation tank 3 through the outlet under the self weight and the pressure difference between the hydrolysis acidification tank 2 and the methanation tank 3.

As a preferred embodiment of the present invention, the sediment discharge port 215 is disposed at the bottom of the hydrolysis acidification tank 2; the sediment discharge port 215 is connected with a spiral discharge machine through a valve and a pipeline; the static pressure generated by the vertical distance between the top of the discharge pipe of the spiral discharging machine and the height of the liquid level in the hydrolysis acidification tank 2 is 5-10kPa greater than the internal pressure of the hydrolysis acidification tank 2.

Specifically, the sediment discharge port 215 is arranged at the bottom, and high-density impurities such as sand grains and the like exist in the hydrolyzed and acidified materials and are discharged through the sediment discharge port 215 at regular time. And (3) carrying out filter pressing on the discharged sediments, sending filter pressing residues and biogas residues together to aerobic composting, and pumping filter pressing solution into a methanation tank 3 for fermentation to generate biogas.

As a preferred embodiment of the present invention, the scum outlet is arranged at the liquid level of the digestive juice; the height of the scum discharge port does not exceed the height of the liquid level of the digestive juice by 20-50 mm; the scum discharge port is communicated with the sealed scum pond through a valve and a pipeline.

As shown in the attached figure 1, as a preferred embodiment of the present invention, the surfaces of the hydrolysis acidification tank 2 and the methanation tank 3 are provided with a second heat preservation layer 208.

As a preferred embodiment of the invention, the methanation tank 3 is of a horizontal structure; the methanation pool 3 is obliquely arranged underground, and the inclination angle of the methanation pool relative to the horizontal plane is 0-0.05 degrees.

Specifically, the methanation tank 3 is horizontally and obliquely arranged and is reversely arranged in parallel with the hydrolysis acidification tank 2, that is, the digestion liquid discharge port 212 of the hydrolysis acidification tank 2 is parallel to the digestion liquid feed port 430 of the methanation tank 3, or vice versa. The bottom height of the digestive juice discharge port 212 of the hydrolysis acidification tank 2 is higher than that of the digestive juice feed port 430 of the methanation tank 3, and the height difference is larger than 0.5-10kPa of the internal pressure difference of the two during normal operation.

Moreover, compared with the prior art, the size construction of the methanation tank 3 is not limited, the construction cost is lower, the dead weight of the fermentation raw materials is effectively utilized, the energy consumption of mechanical stirring is reduced, and the problems of high solid content, poor fluidity and large material feeding and conveying difficulty of dry fermentation materials are solved.

As a preferred embodiment of the invention, the methanation pool 3 is in various structures (such as a long cylinder, a U-shaped groove and the like) to prevent aggregate/dead corners.

As a preferred embodiment of the invention, the methanation pool 3 is formed by welding stainless steel plates or enameled steel plates, and when the stainless steel plates are adopted, the inner wall needs to be subjected to anticorrosion treatment.

As a preferred embodiment of the present invention, a plurality of second baffle plates 445 are disposed in the methanation tank 3; the height of the second baffle 445 is 1/4-1/2 of the liquid level of the digestion liquid in the methanation tank 3.

Specifically, the methanation tank 3 is provided with three or more second baffles 445 with different inside aspect ratios, and the second baffles 445 intercept sludge and strains and prolong the retention time of the digestive juice.

As a preferred embodiment of the invention, the hydraulic retention time of the methanation cell 3 is 15-30 days.

As shown in fig. 6 to 9, as a preferred embodiment of the present invention, the methanation tank 3 is provided with:

a digester feed inlet 430, a discharge outlet 418 and a biogas outlet 410;

second stirring means for stirring the mixture;

an acidolysis regulating and dosing device for regulating the pH value in the methanation tank 3;

and one or more of at least the following detection devices, the detection devices comprising:

the second temperature detection device is used for detecting the temperature in the methanation tank 3;

the second pressure detection device is used for detecting the pressure in the methanation tank 3;

the second pH detection device is used for detecting the pH value of the material in the methanation tank 3;

the second ORP detection device is used for detecting the ORP value of the material in the methanation pool 3;

and the second liquid level detection device is used for detecting the height of the material in the methanation pool 3.

Specifically, a second pH detection device interface, a second ORP detection device interface, and a second temperature detection device interface 438 are arranged on the methanation cell 3, and are respectively used for installing a second pH detection device, a second ORP detection device, and a second temperature detection device. And the acidolysis adjusting and dosing device is arranged near the digestive juice feeding hole 430, and is used for adding an adjusting medicament into the methanation tank 3 through a medicament inlet 428. For example, when the methanation tank 3 is over-acidified or the pH value in the methanation tank 3 is seriously unbalanced, a certain regulating agent can be properly added to improve the growth environment of microorganisms in the methanation tank 3.

In addition, an explosion-proof port 408 and a foam removing port 415 are further arranged on the methanation tank 3 and are used for preventing overpressure explosion of the methanation tank 3 and removing foam on the surface of biogas slurry respectively.

As shown in fig. 6 to 9, as a preferred embodiment of the present invention, a second manhole 485 and a second observation hole are further disposed on the methanation cell 3.

As a preferred embodiment of the invention, the discharge port is communicated with a filter pressing device; the filter pressing device uses plate frame filter pressing or stacked spiral filter pressing.

Specifically, the discharge port is communicated with a filter pressing device, after filter pressing, the biogas slurry is separated from biogas residues, and the biogas slurry is quantitatively conveyed to the methanation tank 3 through a sewage pump. The biogas residues are conveyed to a compost reactor 1 through a sealed or semi-sealed belt conveying system to be decomposed and dried to prepare the organic fertilizer.

As a preferred embodiment of the present invention, the second stirring device is a mechanical stirring device, a biogas stirring device or a biogas slurry stirring device.

Specifically, the methanation tank 3 is provided with a biogas slurry stirring port 440, which can adopt various modes such as mechanical stirring, biogas stirring and biogas slurry stirring, preferably biogas stirring and biogas slurry stirring.

In a preferred embodiment of the invention, the biogas stirring is to pump out biogas above the liquid level of the digestion solution in the methanation tank 3 by a biogas pump and introduce the biogas from the bottom and the lateral lower part of the methanation tank 3, so as to generate strong gas reflux, drive the sinking sludge to float upwards and promote the methane gas to smoothly separate from the digestion solution.

As a preferred embodiment of the present invention, the biogas stirring requires at least one outlet and three inlets.

As a preferred embodiment of the invention, the biogas slurry stirring is to pump out the biogas slurry from the bottom of the methanation tank 3 through a sludge pump and inject the biogas slurry tangentially from the side upper part (lower than the height of the digestion solution), so that strong circumferential flow is formed in the methanation tank 3, and the biogas slurry stirring effect is realized.

As a preferred embodiment of the invention, the biogas slurry stirring needs at least one biogas slurry outlet and two biogas slurry spraying inlets per set.

As a preferred embodiment of the invention, the biogas stirring and biogas slurry stirring need to be arranged in one or more than one set in each area isolated between each baffle plate and the baffle plate and between the baffle plate and the feeding and discharging ends.

As a preferred embodiment of the invention, the biogas stirring and the biogas slurry stirring cause the moving speed of the digestion liquid in the methanation pool 3 not to exceed 0.5m/s in the stirring process.

As a preferred embodiment of the invention, the biogas stirring and biogas slurry stirring are carried out, wherein the stirring time is 5-10min each time and 3-4 times per day.

As a preferred embodiment of the present invention, the biogas stirring and the biogas slurry stirring may be separately or simultaneously performed.

As a preferred embodiment of the invention, when the hydrolytic acidification bacteria and the methanogen are subjected to moderate anaerobic digestion, the first temperature value is 40-55 ℃, and the second temperature value is 30-35 ℃; when the hydrolytic acidification bacteria and the methanogen are subjected to high-temperature anaerobic digestion, the first temperature value is 65-70 ℃, and the second temperature value is 50-55 ℃.

As shown in FIG. 1, the two-phase anaerobic digestion fermentation system further comprises, as a preferred embodiment of the present invention:

a feed vessel 101; the feeding container 101 is communicated with the hydrolysis acidification tank 2 through a material pipeline 242; a gravity automatic control valve is arranged on the material pipeline 242; the feeding container 101 is provided with a third stirring device for mixing materials.

Specifically, the feeding container 101 may be of various structures such as a square structure and a circular structure, and the anaerobic digestion materials are crushed and then mixed in the feeding container 101 according to a certain ratio. The feeding container 101 is provided with a third stirring device, so that the materials with different solid contents can be uniformly mixed, and the materials can flow into the hydrolysis acidification tank 2 through self weight.

As a preferred embodiment of the present invention, the static pressure generated by the difference between the bottom of the feeding container 101 and the liquid level in the hydrolysis acidification tank 2 is not less than 10 kPa. Preferably, the difference between the liquid level of the bottom of the feeding container 101 and the liquid level of the hydrolysis acidification tank 2 is not less than 20 kPa.

Example 2

In this example, the two-phase anaerobic digestion fermentation system of example 1 was used to perform actual fermentation, and the fermentation process was as follows:

the residual heat generated by the reaction of the composting raw materials in the composting reactor 1 heats the medium (water) to 60-65 ℃ through the heat exchanger 102, flows into the first medium circulating container 115, exchanges heat through the first jacket 268 and the heat exchange coil 255 of the hydrolysis acidification tank 2 and the second jacket 465 of the methanation tank 3, returns to the second medium circulating container 120, and is finally pumped into the heat exchanger 102 of the composting reactor 1 for heating.

After the kitchen garbage and the agricultural straws are primarily crushed, the kitchen garbage and the agricultural straws are mixed with the breeding excrement according to the proportion of 1: 1: 1, feeding the biogas slurry into a feeding container 101, adding a certain amount of biogas slurry discharged from a methanation tank 3, controlling the solid content (TS) to be 20-28%, and controlling the C/N ratio to be (20-30): 1 range, and the hydrolytic acidification raw material with certain fluidity can be obtained by stirring evenly. The raw materials automatically flow into the hydrolysis acidification tank 2 through a material pipeline 242 (hydrolysis acidification slag liquid accounting for 20-30% of the effective volume is added in advance in a container to provide a bacterial source for hydrolysis acidification, or inoculation biogas slurry is used for acclimatization for more than 60 days to enable the pH value to be less than 6). Circulating hot water at 60-65 deg.C is used to heat the digestive juice via heat exchanger 102, and gradually heated to 55-60 deg.C (high temperature hydrolysis acidification) or 40-45 deg.C (medium temperature hydrolysis acidification).

In order to ensure smooth feeding, the height difference between the bottom of the feeding container 101 and the liquid level of the hydrolysis acidification tank 2 is not less than 1500mm, so that the static pressure of the material in the material pipeline 242 is slightly higher than the internal pressure of the container of the hydrolysis acidification tank 2 by 1-10 kPa. In the hydrolysis acidification tank 2, the digestion raw material is gradually digested and degraded, gradually moves to the digestion liquid discharge port 212 under stirring and self-gravity pushing, and automatically flows into the methanation tank 3 through the siphon 425 via the digestion liquid discharge port 212 after 4-8 days. In order to prevent the digestion raw material from being short-circuited and flowing into the methanation tank 3 without being degraded completely, a plurality of first baffle plates 228 are arranged in the hydrolytic acidification tank 2, and the first baffle plates 228 have the function of intercepting hydrolytic acidification bacteria. A small amount of impurities with higher density, such as bone fragments and sand, in the digestion raw materials can be deposited at the bottom of the outlet end of the hydrolysis acidification tank 2 along with time, and a spiral discharging device is required to be used for discharging from a sediment discharging hole 215 at regular time. As with the feed, the hydrostatic pressure of the digester effluent outlet 212 should be 1-10kPa higher than the internal pressure of the hydrolysis acidification tank 2 container to ensure that the gas and digester effluent in the hydrolysis acidification tank 2 container do not leak from the digester effluent outlet 212. Meanwhile, the hydrolyzed and acidified gas passes through the gas outlet 200 and is directly discharged after acid removal and deodorization. In normal operation, the optimization process of the hydrolysis acidification tank 2 is as follows: the temperature is 38 plus or minus 3 ℃ (medium temperature fermentation) and 58 plus or minus 3 ℃ (high temperature fermentation), the hydraulic retention time is 5-8 days (medium temperature fermentation) and 4-6 days (high temperature fermentation), the pH value is 4.5-6.0, -350mV < ORP < -250mV, and 0< pressure <1.5 kPa. At this time, the hydrolysis acid gas composition is: carbon dioxide content > 82%, methane < 0.1%; 18g/L < VFAs <2.8g/L in the digested feed.

After the water digestion solution flows into the methanation pool 3, under the action of methanogens and the optimized working condition, most of the fatty acid organic matters are converted into the methane with high methane content. The methanation tank 3 is stirred by biogas slurry or biogas. When the biogas slurry is stirred, the biogas slurry is pumped out through the biogas slurry stirring port 440 at the upper side and flows into the bottom and the other stirring port at the upper side under the action of the biogas slurry pump. When the biogas slurry is stirred, the biogas slurry flows out and flows into the biogas container in a tangential direction, so that the raw materials are digested to form a strong circumferential flow under the stirring of the biogas slurry. The biogas stirring adopts the arrangement similar to biogas slurry stirring. In the difference, the biogas is extracted from a gas collection area above the methanation tank 3 through a fuel gas pump and then is injected into the digestion raw material through three inlets arranged at the bottom and the side wall. In order to ensure that the digestive juice can smoothly flow into the methanation tank 3, the tail part of the hydrolysis acidification tank 2 is 200-800mm higher than the head part of the methanation tank 3 in the elevation arrangement so as to balance the internal pressure difference between the two.

The biogas generated by the methanation tank 3 is discharged through a biogas outlet 410, is sent into a gas storage cabinet after purification processes such as desulfurization and the like, and can be further decarbonized to produce artificial natural gas. The biogas slurry flows out through a discharge port 418, the biogas residues are sent to compost after filter pressing, the biogas slurry is gathered into a biogas slurry container, then part of the biogas slurry is sent to a feeding container 101 through a biogas slurry pump, the solid content of the digestion raw materials is adjusted, and the rest part of the biogas slurry is sent to compost.

The optimization process of the methanation tank 3 comprises the following steps: the temperature is 35 plus or minus 2 ℃ (medium temperature fermentation) and 53 plus or minus 2 ℃ (high temperature fermentation), the hydraulic retention time is 20-30 days (medium temperature fermentation) and 15-30 days (high temperature fermentation), the pH value is 6.8-7.8, -450mV < ORP < -600mV, and the pressure is 0.5< 1.8 kPa. At this time, the components of the biogas are as follows: methane > 65%, carbon dioxide < 23%.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims (10)

1. A two-phase dry anaerobic digestion fermentation system, comprising:

a hydrolysis acidification pool; the hydrolysis acidification tank is internally provided with hydrolysis acidification bacteria for performing hydrolysis acidification treatment on the materials;

a methanation tank; the methanation pool is provided with methanogens; the methanation tank is communicated with the hydrolysis acidification tank, and the digestion raw materials subjected to hydrolysis acidification automatically flow into the methanation tank through self weight and pressure difference and are decomposed into biogas slurry, biogas residues and biogas by methanogens;

the composting reactor is used for composting the mixture of the biogas residues and the biogas slurry generated by the methanation tank and the specified raw materials, and heat energy generated in the composting process is supplied to the heat exchange device;

a heat exchange device; the heat exchange device utilizes the heat energy supplied by the composting reaction tank to keep the hydrolysis acidification tank and the methanation tank at preset temperature.

2. The two-phase dry anaerobic digestion fermentation system according to claim 1, characterized in that biogas slurry is added into the material entering the hydrolytic acidification tank in a predetermined proportion; and transferring the sediments and the scum generated in the hydrolysis acidification tank, the biogas residues generated in the methanation tank and the residual biogas slurry to the composting reactor for composting.

3. The two-phase dry anaerobic digestion fermentation system according to claim 1, wherein said heat exchange means comprises:

the heat exchanger is used for acquiring heat energy generated in the composting process of the composting reactor;

a first medium circulation vessel in communication with the heat exchanger; supplying the medium of a first temperature value generated in the heat exchanger to the first medium circulation vessel;

a second medium circulation vessel in communication with the heat exchanger; the medium with the second temperature value in the second medium circulation container is supplied to the heat exchanger; the first temperature value is greater than the second temperature value;

the first jacket is arranged on the outer surface of the hydrolysis acidification tank; the first jacket is communicated with a first medium circulation container and a second medium circulation container;

the heat exchange coil is arranged inside the hydrolysis acidification tank; the heat exchange coil is communicated with the first medium circulation container and the second medium circulation container;

the second jacket is arranged on the outer surface of the methanation tank; the second jacket is in communication with the first medium circulation vessel and the second medium circulation vessel.

4. The two-phase dry anaerobic digestion fermentation system according to claim 3, wherein the first medium circulation vessel and the second medium circulation vessel are communicated with the heat exchanger, the first jacket and the second jacket through medium pipes; the outer surfaces of the composting reactor, the first medium circulating container, the second medium circulating container and the medium pipeline are respectively provided with a first heat-insulating layer with the thickness not less than 50mm and the heat conductivity not more than 0.04 kJ/(m.h.DEG C); and second heat-insulating layers are arranged on the surfaces of the hydrolysis acidification tank and the methanation tank.

5. The two-phase dry anaerobic digestion fermentation system according to claim 3, wherein when said hydrolytic acidification bacteria and methanogen are performing a warm anaerobic digestion, the first temperature value is 40-55 ℃ and the second temperature value is 30-35 ℃; when the hydrolytic acidification bacteria and the methanogen are subjected to high-temperature anaerobic digestion, the first temperature value is 65-70 ℃, and the second temperature value is 50-55 ℃.

6. The two-phase dry anaerobic digestion fermentation system according to claim 1, wherein the composting reactor is a sealed reaction chamber in the form of a rotary kiln structure; the sealed reaction bin comprises a bin body and a driving piece for driving the bin body to rotate.

7. The two-phase dry anaerobic digestion fermentation system according to claim 1, wherein the composting reactor is inclined with respect to the horizontal plane at an angle of 0.1-1 °; the hydrolysis acidification tank and the methanation tank are both of a horizontal structure; the hydrolysis acidification tank and the methanation tank are obliquely arranged underground, the inclination angle of the hydrolysis acidification tank relative to the horizontal plane is 0.01-1 degrees, and the inclination angle of the methanation tank relative to the horizontal plane is 0-0.05 degrees.

8. The two-phase dry anaerobic digestion fermentation system according to claim 1, wherein the hydrolysis acidification tank is provided with:

a material inlet and a gas outlet;

the first stirring device is used for stirring materials;

a digestive juice discharge port for discharging digestive juice, a sediment discharge port for discharging sediment and a scum discharge port for discharging scum;

and one or more of at least the following detection devices, the detection devices comprising:

the first temperature detection device is used for detecting the temperature in the hydrolysis acidification tank;

the first pressure detection device is used for detecting the pressure in the hydrolysis acidification tank;

the first pH detection device is used for detecting the pH value of the material in the hydrolysis acidification tank;

the first ORP detection device is used for detecting the ORP value of the materials in the hydrolytic acidification tank;

and the first liquid level detection device is used for detecting the height of the material in the hydrolysis acidification tank.

9. The two-phase dry anaerobic digestion fermentation system according to claim 1, wherein the methanation tank is provided with:

a digestive juice inlet, a discharge outlet and a methane outlet;

second stirring means for stirring the mixture;

an acidolysis regulating and dosing device for regulating the pH value in the methanation tank;

and one or more of at least the following detection devices, the detection devices comprising:

the second temperature detection device is used for detecting the temperature in the methanation pool;

the second pressure detection device is used for detecting the pressure in the methanation pool;

the second pH detection device is used for detecting the pH value of the material in the methanation pool;

the second ORP detection device is used for detecting the ORP value of the material in the methanation cell;

and the second liquid level detection device is used for detecting the height of the material in the methanation pool.

10. The two-phase dry anaerobic digestion fermentation system according to claim 1, further comprising:

a feed vessel; the feeding container is communicated with the hydrolysis acidification tank through a material pipeline; a gravity automatic control valve is arranged on the material pipeline; and a third stirring device for mixing materials is arranged in the feeding container.

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