Dry-type high-temperature anaerobic fermentation equipment and method for circulating straws in biogas slurry

Abstract

The invention discloses biogas slurry internal circulation straw dry-type high-temperature anaerobic fermentation equipment and method, the equipment comprises a fermentation tank body, the inner side and the outer side of the fermentation tank body are respectively provided with a heating facility and a heat preservation layer, and a gas storage area sieve plate, a hydrolytic acidification isolation plate and a secondary fermentation area sieve plate are sequentially arranged in the fermentation tank body from top to bottom. The straw feeding, staying and moving modes of the anaerobic fermentation reactor are optimally designed, and fed straw enters the fermentation reactor through a gravity feeding pipeline under the action of pressure equipment; then sequentially passing through a hydrolysis area, an acidification acid-producing area and a main methane-producing area, and then discharging the biogas residue out of the anaerobic fermentation reactor through a biogas residue discharging pipeline; under the action of gravity and pressure, movement / discharging of straw in a gravity state and internal circulation of biogas slurry are realized, a flow guide structure in the anaerobic fermentation equipment is optimally designed, the problems of upward floating and crusting of light straw and the like can be effectively prevented, the problem that a traditional stirring mode cannot adapt to stirring of substances with high solid content is solved, and mass transfer and heat transfer processes under the high solid content are strengthened.

Description

Technical Field

[0001] The invention relates to the technical field of biogas production, and more specifically to a biogas liquid internal circulation straw dry-type high-temperature anaerobic fermentation device and method. Background Art

[0002] In recent years, with the intensive development of the breeding industry and the popularization of fossil energy, straw, which was originally used as livestock feed and rural life energy, has gradually become agricultural production waste, resulting in resource waste and causing a series of environmental problems. Anaerobic biogas production from straw can bring significant energy and environmental benefits and is considered to be one of the most promising ways to solve the problem. Anaerobic fermentation is mainly divided into two process technologies: wet anaerobic fermentation and dry anaerobic fermentation according to concentration.

[0003] The straw wet anaerobic technology is mature, but it has the following disadvantages: 1. The straw density is small, and it is easy to float and form a crust and block the discharge pipe, which poses a safety hazard; 2. The straw and the inoculum are separated, which reduces the gas production efficiency of the reaction system; 3. The mechanical stirring consumes a lot of energy; 4. The anaerobic concentration is low, and a large amount of biogas liquid is produced, causing environmental pollution. The result is low anaerobic efficiency and restricts the development of the straw biogas industry.

[0004] Straw dry anaerobic fermentation technology has the advantages of water conservation, large processing capacity, large gas production, strong volumetric capacity, and low processing cost. There are many studies on dry anaerobic abroad and it is relatively mature, and industrial applications have been reported; due to strict confidentiality, the technology is difficult to obtain; and due to the differences in material properties at home and abroad, the direct use of foreign dry anaerobic equipment causes many engineering problems that cannot be solved, limiting the promotion and application of dry anaerobic fermentation technology. Although there are studies on dry anaerobic fermentation technology and equipment in China, the mass transfer, heat transfer, acidification problems caused by high solid content materials in dry anaerobic fermentation and the contradiction between large-scale material input and output and anaerobic sealing state have not been effectively solved. And there are still the following problems:

[0005] (1) The dry fermentation reaction substrate concentration is high, and mass and energy transfer and diffusion are difficult, which easily leads to excessive accumulation of intermediate metabolites during anaerobic startup and operation, thus forming feedback inhibition;

[0006] (2) The dry fermentation substrate is difficult to distribute evenly and has poor fluidity, resulting in poor temperature uniformity in the equipment, especially the high-temperature anaerobic system is difficult to control and the continuous operation is unstable;

[0007] (3) Dry fermentation has high stirring resistance and the substrate is difficult to stir and mix;

[0008] (4) The dry fermentation of old materials and sludge recirculation relies on external equipment such as pumps, which consumes a lot of energy.

[0009] Therefore, it is necessary to research and develop a high-temperature anaerobic fermentation equipment and method for straw with internal circulation of biogas slurry to solve the above problems. Summary of the invention

[0010] The purpose of the present invention is to provide a straw dry high-temperature anaerobic fermentation equipment and method with internal circulation of biogas slurry in view of the problems existing in the prior art. By moving / discharging the straw under the gravity state, internal circulation of biogas slurry, and optimizing the design of the internal guide structure of the anaerobic fermentation equipment, the problem that the traditional stirring method cannot adapt to the stirring of materials with high solid content is solved, the mass transfer and heat transfer process under high solid content is strengthened, the pH value in the acidification stage is accurately controlled, the anaerobic temperature uniformity of the equipment is improved, the reaction conditions in the hydrolysis, acidification and methanation stages are optimized, the material circulation / reflux energy consumption in the anaerobic stage is eliminated or reduced, the production cost of straw biogas production is reduced, and the stable operation of dry anaerobic fermentation is realized, thereby generating higher environmental benefits, economic benefits and social benefits.

[0011] To achieve the above object, the present invention provides the following technical solutions:

[0012] A biogas slurry internal circulation straw dry high temperature anaerobic fermentation equipment, comprising a fermentation tank body, wherein heating facilities and insulation layers are respectively arranged on the inner and outer sides of the fermentation tank body, wherein a gas storage area sieve plate, a hydrolysis acidification isolation plate and a secondary fermentation area sieve plate are sequentially arranged from top to bottom inside the fermentation tank body, wherein the hydrolysis acidification isolation plate and the secondary fermentation area sieve plate are both fitted and connected with the heating facilities, and a transition section is reserved between the hydrolysis acidification isolation plate and the secondary fermentation area sieve plate;

[0013] A secondary fermentation area bottom plate is fixedly connected between the bottom end of the secondary fermentation area sieve plate and the inner wall of the fermentation tank body, and a closed secondary fermentation area is formed between the secondary fermentation area bottom plate, the secondary fermentation area sieve plate and the inner wall of the fermentation tank body, and a gas storage area is formed between the gas storage area sieve plate and the top wall of the fermentation tank body cavity, and the secondary fermentation area and the gas storage area are connected through a biogas slurry lifting pipe, so that the biogas slurry in the secondary fermentation area enters the gas storage area through the biogas slurry lifting pipe;

[0014] A fermentation tank bottom plate extending out of the fermentation tank body is welded to the bottom of the contact portion between the secondary fermentation zone bottom plate and the secondary fermentation zone sieve plate, and a hydrolysis zone, an acidification acid production zone and a main methane production zone are sequentially distributed from top to bottom in the space from the bottom of the gas storage zone sieve plate to the fermentation tank bottom plate, a plurality of evenly distributed pores are opened on the gas storage zone sieve plate, and a biogas slurry spraying mechanism is hoisted at the bottom of the gas storage zone sieve plate, so that the biogas slurry entering the gas storage zone flows into the hydrolysis reaction zone and the methane production zone respectively through the pores and the biogas slurry spraying mechanism;

[0015] A monitoring module is also provided inside the fermentation tank body for real-time monitoring of the material processing conditions inside the fermentation tank body.

[0016] Preferably, a gravity feed pipeline penetrating the sieve plate of the gas storage area is fixedly connected to the top of the fermentation tank body, the gravity feed pipeline connects the outside of the fermentation tank body with the hydrolysis area, and a pressure device is provided at its input end for feeding the straw into the hydrolysis area;

[0017] The number of the gravity feed pipeline and the biogas slurry lifting pipe is at least three, and the plurality of gravity feed pipelines and the biogas slurry lifting pipes are distributed in a ring array around the axis of the fermentation tank body;

[0018] The diameter of the biogas slurry lifting pipe is less than 150 mm;

[0019] A straw feeding control valve is installed on the gravity feeding pipeline.

[0020] Preferably, a biogas slurry discharge pipeline penetrates the bottom of the outer wall of the fermentation tank body, and one end of the biogas slurry discharge pipeline extends to the inner bottom of the secondary fermentation area. A biogas slurry discharge control valve is installed on the biogas slurry discharge pipeline.

[0021] Preferably, a biogas discharge pipe communicating with the gas storage area is provided on the top of the fermentation tank body, and a biogas discharge control valve is installed on the biogas discharge pipe.

[0022] Preferably, the hydrolysis and acidification isolation plate and the secondary fermentation zone sieve plate are both configured as annular structures, and the cross-section of the outer wall of the hydrolysis and acidification isolation plate is V-shaped, and the distance d between the middle V-shaped end of the hydrolysis and acidification isolation plate (7) and the fermentation tank body (4) and the inner circle radius r of the straight cylindrical section of the fermentation tank body (4) satisfy the following expression:

[0023]

[0024] The included angle of the middle V-shaped end of the hydrolysis and acidification isolation plate is between 100° and 135°, and the installation angle between the plates on both sides and the inner wall of the fermentation tank is between 25° and 45°; the outer side of the middle V-shaped end of the hydrolysis and acidification isolation plate is a rounded structure.

[0025] The biogas slurry spraying mechanism comprises a drainage pipe penetrating the sieve plate of the gas storage area, a spray distribution plate is arranged at the bottom of the drainage pipe, and the bottom of the spray distribution plate is open and extends to the main methane production area;

[0026] The spray distribution plate is configured as a conical cover, the inner surface of which is opened with holes, and the cone line angle of the spray distribution plate is configured to be 95°-110°.

[0027] Preferably, the bottom plate of the fermentation tank is configured to be funnel-shaped, and a biogas residue discharge pipeline is connected at the bottom axis thereof, and a biogas residue discharge control valve is installed on the biogas residue discharge pipeline;

[0028] The bottom plate of the secondary fermentation area is installed horizontally; the angle between the sieve plate of the secondary fermentation area and the bottom plate of the secondary fermentation area is between 60° and 75°; the installation angle between the bottom plate of the fermentation tank and the bottom plate of the secondary fermentation area is between 110° and 135°.

[0029] Preferably, the monitoring module comprises:

[0030] A pH meter, used to monitor the pH value of the biogas slurry in the secondary fermentation area, which is located inside the fermentation tank and at a position corresponding to the secondary fermentation area;

[0031] The radar level meter is used to sense the height of the material in the fermentation tank body. The radar level meter is located inside the fermentation tank body and corresponds to the hydrolysis zone.

[0032] Preferably, the fermentation equipment also includes a display interface, whose connection end is electrically connected to a controller, and the input and output ends of the controller are respectively provided with an A / D converter and a D / A converter, wherein the pH meter and the radar level meter are both electrically connected to the A / D converter, and the straw feed control valve, the sludge discharge control valve, the biogas discharge control valve are all electrically connected to the D / A converter.

[0033] A method for dry high-temperature anaerobic fermentation of straw with internal circulation of biogas slurry is provided, which adopts the above-mentioned dry high-temperature anaerobic fermentation equipment of biogas slurry with internal circulation of straw to carry out operation, and comprises the following steps:

[0034] S1, control the heating facility to heat in a cyclic manner, and feed the straw from the gravity feed pipeline into the fermentation tank under pressure to the top of the hydrolysis zone;

[0035] S2. Under the action of gravity and pressure, the straw passes through the hydrolysis zone, acidification and acid production zone, primary methane production zone and secondary fermentation zone in sequence, completing the hydrolysis, acidification and acid production and methane production processes respectively;

[0036] S3. Under the action of gravity and pressure, the water in the reaction materials is squeezed out and enters the secondary fermentation area through the sieve plate of the secondary fermentation area; the biogas slurry in the secondary fermentation area is driven by the generated methane gas and lifted to the gas storage area through the biogas slurry lifting pipe;

[0037] S4, by changing the opening of the biogas discharge control valve, the internal pressure of the gas storage area is adjusted to ensure that the biogas slurry in the secondary fermentation area enters the gas storage area along with the biogas; under the action of the internal pressure, part of the biogas slurry in the gas storage area is sprayed onto the material in the hydrolysis area through the sieve plate of the gas storage area, and the other part is sprayed onto the material in the main methanogenic area through the biogas slurry spraying mechanism, so as to adjust the bacterial colonies in the hydrolysis area and the methanogenic area;

[0038] S5, using the monitoring module to obtain the material height in the fermentation tank and the pH value of the generated biogas slurry, comparing with the set threshold, adjusting the opening of the straw feed control valve and the biogas slurry discharge control valve, so that the gravity feed pipeline and the biogas slurry discharge pipeline are filled with materials; opening the biogas slurry discharge control valve in a timely manner to discharge part of the biogas slurry or add bacterial agents to adjust the biogas slurry quality in the secondary fermentation area, and entering S6;

[0039] S6, open the biogas slurry discharge control valve and the biogas residue discharge control valve, discharge the fermented biogas slurry from the biogas slurry discharge pipeline, and discharge the biogas residue through the biogas residue discharge pipeline, and then cycle S1-S5.

[0040] Technical effects and advantages of the present invention:

[0041] 1. By optimizing the design of the straw feeding, retention and movement mode of the anaerobic fermentation reactor, the straw feed enters the fermentation reactor through the gravity feeding pipeline under the action of the pressure equipment; under the action of gravity and pressure, the straw passes through the hydrolysis zone, acidification and acid production zone and the main methane production zone in turn, and finally discharges from the anaerobic fermentation reactor through the biogas residue discharge pipeline; under the action of gravity and pressure, the movement / discharging of the straw under the gravity state, the internal circulation of the biogas slurry, and the optimized design of the internal guide structure of the anaerobic fermentation equipment can be realized, which can effectively prevent the floating and crusting of lightweight straw, and solve the problem that the traditional stirring method cannot adapt to the stirring of high solid content materials, and strengthen the mass transfer and heat transfer process under high solid content;

[0042] 2. Through the scientific design of the hydrolysis and acidification isolation plate, the phase interface between the hydrolysis zone and the acidification and acid production zone is artificially increased, and the mutual interference between the colonies in the hydrolysis and acidification and acid production stages is reduced, which is conducive to the precise control of the bacterial community suitable for the hydrolysis and acidification and acid production stages; the pH value in the acidification stage is precisely controlled to improve the anaerobic temperature uniformity of the equipment, optimize the reaction conditions in the hydrolysis, acidification and methanation stages, eliminate or reduce the material circulation / reflux energy consumption in the anaerobic stage, reduce the production cost of straw biogas, and achieve the stable operation of dry anaerobic fermentation, thereby generating higher environmental, economic and social benefits, and effectively solving the problems of wet anaerobic straw crusting, low hydrolysis rate of dry anaerobic fermentation, difficulty in early warning of dry fermentation instability, high energy consumption of dry fermentation stirring, low conversion rate of intermediate acid to acetic acid, poor temperature field uniformity caused by mass transfer and heat transfer difficulties, and adverse effects of large-scale inflow and outflow of air on fermentation;

[0043] 3. The equipment and high-temperature anaerobic fermentation method provided by the present invention overcome the mass transfer, heat transfer and acidification problems of dry straw fermentation, solve the contradiction between large-scale material input and output and anaerobic sealing state, ensure the stable and continuous operation of the anaerobic process during the anaerobic startup and operation stages under dry high-temperature conditions, and have positive significance for the large-scale industrial application of domestic biogas production. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 The overall structural diagram of the straw dry-type high-temperature anaerobic fermentation equipment with internal circulation of biogas slurry provided by the present invention;

[0045] Figure 2 A first perspective stereogram of a fermentation tank and its connecting parts in the present invention;

[0046] Figure 3 A second perspective stereogram of the fermentation tank and its connecting parts in the present invention;

[0047] Figure 4 A top view of the fermentation tank and its connecting parts in the present invention;

[0048] Figure 5 For the present invention Figure 4 AA sectional view of the structure shown;

[0049] Figure 6 For the present invention Figure 4 A BB-section view of the structure shown;

[0050] Figure 7 It is a system control flow chart of the intelligent monitoring system based on the monitoring module in the present invention.

[0051] In the figure:

[0052] 1-Straw feeding control valve; 2-Gravity feeding pipeline; 3-Gas storage area sieve plate; 4-Fermentation tank body; 5-Heating facilities; 6-Monitoring module; 7-Hydrolysis and acidification isolation plate; 8-Slurry discharge control valve; 9-Slurry discharge pipeline; 10-Secondary fermentation area bottom plate; 11-Fermentation tank bottom plate; 12-Slurry residue discharge pipeline; 13-Slurry residue discharge control valve; 14-Secondary fermentation area sieve plate; 15-Slurry lifting pipe; 16-Return slurry spray mechanism; 17-Biogas discharge pipe; 18-Biogas discharge control valve; 19-Spray distribution plate; 20-Display interface; 21-Controller;

[0053] 601-pH meter; 602-radar level meter;

[0054] A-gas storage area; B-hydrolysis area; C-acidification and acid production area; D-main methane production area; E-secondary fermentation area. DETAILED DESCRIPTION

[0055] An embodiment of the present invention is further described below in conjunction with the accompanying drawings:

[0056] Refer to the instruction manual Figure 1-6As shown, a kind of high-temperature anaerobic fermentation equipment of straw dry type with internal circulation of biogas slurry comprises a fermentation tank body 4, of which heating facilities 5 and insulation layers are respectively arranged on the inner and outer sides thereof. Specifically, the insulation layer is made of insulation material, and the heating facility 5 can adopt a spiral heating tube, which is arranged as a spiral structure made of heat-conducting metal, surrounding and fitting on the inner wall of the fermentation tank body 4, wherein the input end and the output end of the spiral heating tube are respectively led out from the top and the bottom of the straight section of the fermentation tank body 4, and an electric heating box is arranged outside, and the hot water in the electric heating box is transported to the spiral heating tube by a pump for heat transfer, and then the water flow circulates back to the electric heating box for continuous heating, and the fermentation tank body 4 is sequentially arranged with a gas storage area sieve plate 3, a hydrolysis and acidification isolation plate 7 and a secondary fermentation area sieve plate 14 from top to bottom, wherein the hydrolysis and acidification isolation plate 7 and the secondary fermentation area sieve plate 14 are both in contact with the heating facility 5. The hydrolysis and acidification isolation plate 7 is connected together, and a transition section is reserved between the hydrolysis and acidification isolation plate 7 and the secondary fermentation zone sieve plate 14; the hydrolysis and acidification isolation plate 7 is scientifically designed, and the phase interface between the material passing through the hydrolysis zone B and the acidification and acid production zone C is artificially increased, so as to reduce the mutual interference between the colonies in the hydrolysis and acidification and acid production stages, which is conducive to the precise regulation of the bacterial community suitable for the hydrolysis and acidification and acid production stages; and the installation distance between the secondary fermentation zone sieve plate 14 and the hydrolysis and acidification isolation plate 7 is determined according to the descending movement speed of the material, so as to ensure that the material in the acidification stage can flow to the heating facility 5 under the action of gravity, ensure the heat demand in the acidification and acid production stage, and improve the ability to convert the intermediate acid into acetic acid; the hydrolysis and acidification isolation plate 7 is installed on the heating facility 5, so as to increase the heat transfer area between the hydrolysis stage and the acidification and acid production end interface and the fermentation material, shorten the heat transfer gradient between the heat source and the material, and effectively transfer the heat to the straw.

[0057] The straw hydrolysis kinetic model used in the present invention is as follows:

[0058] C=k 1 *C H0 *(e -k 1 *t -e -k 2 *t ) / (k 2 -k 1 )+k 3 *C C0 *(e -k 3 *t -e -k 4 *t ) / (k 4 -k 3 )

[0059] Wherein, t represents the hydrolysis time;

[0060] C represents the concentration of hydrolyzate at time t (g / L);

[0061] C H0 represents the initial concentration of hemicellulose g / L;

[0062] C C0 represents the initial concentration of hemicellulose g / L;

[0063] k 1 , k 2 It represents the reaction rate constant h-1 of hemicellulose at various temperatures;

[0064] k 3 , k 4 Represents the reaction rate constant of cellulose at various temperatures.

[0065] A secondary fermentation area bottom plate 10 is fixedly connected between the bottom end of the secondary fermentation area sieve plate 14 and the inner wall of the fermentation tank body 4, and a closed secondary fermentation area E is formed between the secondary fermentation area bottom plate 10, the secondary fermentation area sieve plate 14 and the inner wall of the fermentation tank body 4, and a gas storage area A is formed between the gas storage area sieve plate 3 and the top wall of the inner cavity of the fermentation tank body 4. The secondary fermentation area E and the gas storage area A are connected through a biogas slurry lifting pipe 15, so that the biogas slurry in the secondary fermentation area E enters the gas storage area A through the biogas slurry lifting pipe 15; the installation position of the secondary fermentation area E is slightly lower than the hydrolysis and acidification plate 7, and under the action of gravity and pressure, some small molecule soluble substances such as carbohydrates, proteins and fats that enter the acidification and acid production stage after hydrolysis uniformly pass through the secondary fermentation area sieve plate 14 to enter the secondary fermentation area E, and complete the methane production process in the secondary fermentation area E.

[0066] In the straw fermentation process, the hydrolysis stage is generally the rate-limiting step, that is, in the fermentation reactor where the straw material moves at a uniform speed, the height of the hydrolysis section is the largest; to ensure that the acidification reaction proceeds fully, the height of the fermentation zone sieve plate 14 is equal to the height of the hydrolysis section.

[0067] A fermentation tank bottom plate 11 extending from the fermentation tank body 4 is welded to the bottom of the contact portion between the secondary fermentation zone bottom plate 10 and the secondary fermentation zone sieve plate 14, and the hydrolysis zone B, the acidification acid production zone C and the main methane production zone D are sequentially distributed from top to bottom in the space from the bottom of the gas storage zone sieve plate 3 to the fermentation tank bottom plate 11. A plurality of evenly distributed pores are provided on the gas storage zone sieve plate 3, and a biogas slurry spraying mechanism is hoisted at the bottom of the gas storage zone sieve plate 3, so that the biogas slurry entering the gas storage zone A flows into the hydrolysis reaction zone B and the methane production zone D through the pores and the biogas slurry spraying mechanism respectively;

[0068] A monitoring module 6 is also provided inside the fermentation tank body 4 for real-time monitoring of the material processing conditions inside the fermentation tank body 4 .

[0069] Further, as a preferred embodiment of the present invention, a gravity feed pipeline 2 penetrating the sieve plate 3 in the gas storage area is fixedly connected to the top of the fermentation tank body 4, and the gravity feed pipeline 2 communicates with the outside of the fermentation tank body 4 and the hydrolysis area B, and a pressure device is provided at its input end for feeding the straw into the hydrolysis area B; specifically, the pressure device can use a push rod to put the straw into the input end of the gravity feed pipeline 2, and cooperate with the pressure device to work, so that the material enters the hydrolysis area B through the gravity feed pipeline 2 under the action of pressure;

[0070] According to the production scale of the fermentation equipment reactor, the number of gravity feed pipelines 2 and biogas slurry lifting pipes 15 is optimized and designed; the number of gravity feed pipelines 2 and biogas slurry lifting pipes 15 is set to at least three, and the multiple gravity feed pipelines 2 and biogas slurry lifting pipes 15 are distributed in a ring array around the axis of the fermentation tank body 4;

[0071] The diameter of the biogas slurry lifting pipe 15 is less than 150 mm;

[0072] A straw feeding control valve 1 is installed on the gravity feeding pipeline 2.

[0073] Furthermore, as a preferred embodiment of the present invention, a biogas slurry discharge pipeline 9 penetrates the bottom of the outer wall of the fermentation tank body 4, and one end of the biogas slurry discharge pipeline 9 extends to the inner bottom of the secondary fermentation area E, and a biogas slurry discharge control valve 8 is installed on the biogas slurry discharge pipeline 9.

[0074] Furthermore, as a preferred embodiment of the present invention, a biogas discharge pipe 17 communicating with the gas storage area A is provided on the top of the fermentation tank body 4 , and a biogas discharge control valve 18 is installed on the biogas discharge pipe 17 .

[0075] Furthermore, as a preferred embodiment of the present invention, the hydrolysis and acidification isolation plate 7 and the secondary fermentation zone sieve plate 14 are both configured as annular structures, and the cross-section of the outer wall of the hydrolysis and acidification isolation plate 7 is V-shaped, and the distance d between the middle V-shaped end of the hydrolysis and acidification isolation plate (7) and the fermentation tank body (4) and the inner circle radius r of the straight cylindrical section of the fermentation tank body (4) satisfy the following expression:

[0076]

[0077] The angle of the middle V-shaped end of the hydrolysis and acidification isolation plate 7 is between 100° and 135°, and the installation angle of the two side plates and the inner wall of the fermentation tank body 4 is between 25° and 45°; the bottom of the hydrolysis and acidification isolation plate 7 can effectively support its top to prevent the hydrolysis and acidification isolation plate 7 from being crushed by the fermentation material; the outer side of the middle V-shaped end of the hydrolysis and acidification isolation plate 7 is rounded, which is conducive to the straw changing the direction of movement to enhance material disturbance and mixing, and prevent the straw from hanging at corners, thereby increasing the probability of hydrolytic bacteria colonizing on the surface of easily hydrolyzable particles of the straw (such as cellulose, hemicellulose, etc.), thereby improving the straw hydrolysis rate and hydrolysis conversion rate.

[0078] The biogas slurry spraying mechanism includes a drainage pipe 16 penetrating the sieve plate 3 of the gas storage area, and a spray distribution plate 19 is arranged at the bottom of the drainage pipe 16, and the bottom of the spray distribution plate 19 is open and extends to the main methane production area D;

[0079] The spray distribution plate 19 is configured as a conical cover with holes on its inner surface, and the cone line angle of the spray distribution plate 19 is configured to be 95°-110°, so as to ensure that the material on the upper surface of the spray distribution plate 19 does not accumulate while covering the cross section of the methane production zone D.

[0080] Furthermore, as a preferred embodiment of the present invention, the fermentation tank bottom plate 11 is configured to be funnel-shaped, and a biogas residue discharge pipeline 12 is connected to the bottom axis thereof, and a biogas residue discharge control valve 13 is installed on the biogas residue discharge pipeline 12;

[0081] The bottom plate 10 of the secondary fermentation area is installed horizontally; according to the viscosity of the biogas slurry, the installation angle of the secondary fermentation area sieve plate 14 and the secondary fermentation area bottom plate 10 is optimized and calculated, and the angle between the secondary fermentation area sieve plate 14 and the secondary fermentation area bottom plate 10 is between 60°-75°; ensure that the biogas slurry enters the secondary fermentation area E through the secondary fermentation area sieve plate 14 in stages under pressure to meet the nutritional needs of the methanogens in the acidophilic secondary fermentation area E. The installation angle of the fermentation tank bottom plate 11 and the secondary fermentation area bottom plate 10 is between 110°-135°; increase the disturbance of the material in the methanogenesis stage; the reduction of the space volume of the main methanogenesis area D matches the weight reduction of the material after anaerobic fermentation to produce methanogens; overcome the excessive local heating caused by excessive local temperature rise leading to premature death of methanogens.

[0082] Further, as a preferred embodiment of the present invention, the monitoring module 6 includes:

[0083] The pH meter 601 is used to monitor the pH value of the biogas slurry in the secondary fermentation zone E. The pH meter 601 is located inside the fermentation tank 4 and corresponds to the secondary fermentation zone E. The pH meter 601 solves the shortcomings of inaccurate pH measurement and inability to measure online in the traditional titration method for anaerobic dry fermentation, and can effectively warn of instability of dry anaerobic fermentation, thereby improving the automation level of anaerobic fermentation and enhancing process reliability.

[0084] The radar level meter 602 is used to sense the height of the material in the fermentation tank body 4. It is located inside the fermentation tank body 4 and corresponds to the position of the hydrolysis zone B.

[0085] Refer to the instruction manual Figure 1 and 7As shown, the fermentation equipment also includes a display interface 20, whose connection end is electrically connected to a controller 21, and the input end and output end of the controller 21 are respectively provided with an A / D converter and a D / A converter, wherein the pH meter 601 and the radar level meter 602 are both electrically connected to the A / D converter, and the straw feed control valve 1, the biogas discharge control valve 13, the biogas liquid discharge control valve 8 and the biogas discharge control valve 18 are all electrically connected to the D / A converter. The monitoring information of the pH meter 601 and the radar level meter 602 are all displayed on the display interface 20, and the pH threshold of the biogas liquid and the material height threshold in the fermentation tank body 4 can be set through the display interface 20, so as to adjust when the set threshold is exceeded. For example, the opening of the straw feed control valve 1 and the biogas discharge control valve 13 is adjusted according to the data of the radar level meter 602, so that the gravity feed pipeline 2 and the biogas discharge pipeline 12 are filled with materials. It is beneficial to fundamentally prevent air from entering the reactor and solve the problem that large-scale inlet and outlet materials bring in air and cause adverse effects on the anaerobic fermentation process. According to the data of pH meter 601, controller 21 controls biogas slurry discharge control valve 8 to open, discharge part of biogas slurry or add bacterial agent to adjust the biogas slurry quality in secondary fermentation area E, improve the automation degree of biogas dry fermentation, and improve the reliability of instability warning.

[0086] A method for dry high-temperature anaerobic fermentation of straw with internal circulation of biogas slurry is provided, which adopts the above-mentioned dry high-temperature anaerobic fermentation equipment of biogas slurry with internal circulation of straw to carry out operation, and comprises the following steps:

[0087] S1, control the heating facility 5 to perform cyclic heating, and feed the straw from the gravity feed pipeline 2 into the fermentation tank 4 under pressure, to the top of the hydrolysis zone B;

[0088] S2. Under the action of gravity and pressure, the straw passes through the hydrolysis zone B, the acidification and acid production zone C, the main methane production zone D and the secondary fermentation zone E in sequence, completing the hydrolysis, acidification and acid production and methane production processes respectively; the above process is in a vertical space and finally discharged from the bottom, which can effectively prevent the lightweight straw from floating up and crusting;

[0089] S3. Under the action of gravity and pressure, the water in the reaction material is squeezed out and enters the secondary fermentation area E through the secondary fermentation area sieve plate 14; the biogas slurry in the secondary fermentation area E is driven by the generated methane gas and lifted to the gas storage area A through the biogas slurry lifting pipe 15;

[0090] S4, by changing the opening of the biogas discharge control valve 18, the internal pressure of the gas storage area A is adjusted to ensure that the flow of the biogas slurry in the secondary fermentation area E enters the gas storage area A along with the biogas; under the action of the internal pressure, part of the biogas slurry in the gas storage area A is sprayed onto the material in the hydrolysis area B through the gas storage area sieve plate 3, and the other part is sprayed onto the material in the main methane production area D through the biogas slurry spraying mechanism, so as to adjust the bacterial colonies in the hydrolysis area B and the methane production area D, reduce the surface viscosity of the straw, and strengthen the heat transfer between the high-concentration material particles by the flow of water on the surface, so as to ensure the uniformity of the fermentation temperature of the material, thereby optimizing the anaerobic fermentation environment in the hydrolysis and methane production stages, enhancing the straw hydrolysis capacity in the hydrolysis area B, and increasing the methane production in the methane production area D;

[0091] S5. Use monitoring module 6 to obtain the material height in the fermentation tank 4 and the pH value of the generated biogas slurry, compare with the set threshold, adjust the opening of the straw feed control valve 1 and the biogas residue discharge control valve 13, so that the gravity feed pipeline 2 and the biogas residue discharge pipeline 12 are filled with materials; it is beneficial to fundamentally prevent air from entering the reactor and solve the problem that large-scale inflow and outflow of materials bring in air and cause adverse effects on the anaerobic fermentation process. Open the biogas slurry discharge control valve 8 in time to discharge part of the biogas slurry or add bacterial agents to adjust the biogas slurry quality in the secondary fermentation area E; improve the automation level of biogas dry fermentation and the reliability of instability warning, and enter S6;

[0092] S6, open the biogas slurry discharge control valve 8 and the biogas residue discharge control valve 13, discharge the fermented biogas slurry from the biogas slurry discharge pipeline 9, and discharge the biogas residue through the biogas residue discharge pipeline 12, and then cycle S1-S5.

[0093] Finally: The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A dry high-temperature anaerobic fermentation equipment for straw with internal circulation of biogas slurry, comprising a fermentation tank body (4), wherein heating facilities (5) and a heat preservation layer are respectively arranged on the inner and outer sides thereof, and characterized in that: The fermentation tank body (4) is provided with a gas storage area sieve plate (3), a hydrolysis and acidification isolation plate (7) and a secondary fermentation area sieve plate (14) in order from top to bottom, wherein the hydrolysis and acidification isolation plate (7) and the secondary fermentation area sieve plate (14) are both closely connected to the heating facility (5), and a transition section is reserved between the hydrolysis and acidification isolation plate (7) and the secondary fermentation area sieve plate (14); A secondary fermentation area bottom plate (10) is fixedly connected between the bottom end of the secondary fermentation area sieve plate (14) and the inner wall of the fermentation tank body (4), and a closed secondary fermentation area (E) is formed between the secondary fermentation area bottom plate (10), the secondary fermentation area sieve plate (14) and the inner wall of the fermentation tank body (4); a gas storage area (A) is formed between the gas storage area sieve plate (3) and the top wall of the inner cavity of the fermentation tank body (4); the secondary fermentation area (E) and the gas storage area (A) are connected via a biogas slurry lifting pipe (15), so that the biogas slurry in the secondary fermentation area (E) enters the gas storage area (A) through the biogas slurry lifting pipe (15); A fermentation tank bottom plate (11) extending out of the fermentation tank body (4) is welded to the bottom of the contact portion between the secondary fermentation zone bottom plate (10) and the secondary fermentation zone sieve plate (14), and a hydrolysis zone (B), an acidification acid production zone (C) and a main methane production zone (D) are sequentially distributed from top to bottom in the space from the bottom of the gas storage zone sieve plate (3) to the fermentation tank bottom plate (11), a plurality of evenly distributed pores are opened on the gas storage zone sieve plate (3), and a biogas slurry spraying mechanism is hoisted at the bottom of the gas storage zone sieve plate (3), so that the biogas slurry entering the gas storage zone (A) flows into the hydrolysis reaction zone (B) and the methane production zone (D) through the pores and the biogas slurry spraying mechanism respectively; A monitoring module (6) is also provided inside the fermentation tank body (4) for real-time monitoring of the material processing conditions inside the fermentation tank body (4).

2. The dry high temperature anaerobic fermentation equipment of straw with internal circulation of biogas slurry according to claim 1, characterized in that: The top of the fermentation tank body (4) is fixedly connected with a gravity feed pipeline (2) penetrating the sieve plate (3) of the gas storage area, the gravity feed pipeline (2) communicates with the outside of the fermentation tank body (4) and the hydrolysis area (B), and a pressure device is provided at its input end for feeding the straw into the hydrolysis area (B); The number of the gravity feeding pipeline (2) and the biogas slurry lifting pipe (15) is at least three, and the plurality of gravity feeding pipelines (2) and the biogas slurry lifting pipes (15) are distributed in a ring array around the axis of the fermentation tank body (4); The diameter of the biogas slurry lifting pipe (15) is less than 150 mm; A straw feeding control valve (1) is installed on the gravity feeding pipeline (2).

3. The biogas slurry internal circulation straw dry high temperature anaerobic fermentation equipment according to claim 1, characterized in that: A biogas slurry discharge pipeline (9) penetrates the bottom of the outer wall of the fermentation tank body (4), and one end of the biogas slurry discharge pipeline (9) extends to the inner bottom of the secondary fermentation area (E). A biogas slurry discharge control valve (8) is installed on the biogas slurry discharge pipeline (9).

4. The biogas slurry internal circulation straw dry high temperature anaerobic fermentation equipment according to claim 1, characterized in that: A biogas discharge pipe (17) communicating with the gas storage area (A) is arranged on the top of the fermentation tank body (4), and a biogas discharge control valve (18) is installed on the biogas discharge pipe (17).

5. The biogas slurry internal circulation straw dry high temperature anaerobic fermentation equipment according to claim 1, characterized in that: The hydrolysis and acidification isolation plate (7) and the secondary fermentation zone sieve plate (14) are both arranged as annular structures, and the outer wall cross section of the hydrolysis and acidification isolation plate (7) is V-shaped, and the distance d between the middle V-shaped end of the hydrolysis and acidification isolation plate (7) and the fermentation tank body (4) and the inner circle radius r of the straight cylindrical section of the fermentation tank body (4) satisfy the following expression: The included angle of the middle V-shaped end of the hydrolysis and acidification isolation plate (7) is between 100° and 135°, and the installation angle between the plates on both sides and the inner wall of the fermentation tank body (4) is between 25° and 45°; the outer side of the middle V-shaped end of the hydrolysis and acidification isolation plate (7) is a rounded structure.

6. The biogas slurry internal circulation straw dry high temperature anaerobic fermentation equipment according to claim 1, characterized in that: The biogas slurry spraying mechanism comprises a drainage pipe (16) penetrating the gas storage area sieve plate (3), a spray distribution plate (19) is arranged at the bottom end of the drainage pipe (16), and the bottom end of the spray distribution plate (19) is open and extends to the main methane production area (D); The spray distribution plate (19) is configured as a conical cover, the inner surface of which is opened with holes, and the cone line angle of the spray distribution plate (19) is configured to be 95°-110°.

7. The dry high temperature anaerobic fermentation equipment of straw with internal circulation of biogas slurry according to claim 1, characterized in that: The fermentation tank bottom plate (11) is configured to be funnel-shaped, and a biogas residue discharge pipeline (12) is connected to the bottom axis thereof, and a biogas residue discharge control valve (13) is installed on the biogas residue discharge pipeline (12); The secondary fermentation area bottom plate (10) is installed horizontally; the angle between the secondary fermentation area sieve plate (14) and the secondary fermentation area bottom plate (10) is between 60° and 75°; and the installation angle between the fermentation tank bottom plate (11) and the secondary fermentation area bottom plate (10) is between 110° and 135°.

8. The biogas slurry internal circulation straw dry high temperature anaerobic fermentation equipment according to claim 1, characterized in that: The monitoring module (6) comprises: A pH meter (601) for monitoring the pH value of the biogas slurry in the secondary fermentation area (E), which is located inside the fermentation tank (4) and at a position corresponding to the secondary fermentation area (E); The radar level meter (602) is used to sense the height of the material in the fermentation tank (4), and is located inside the fermentation tank (4) and at a position corresponding to the hydrolysis zone (B).

9. The dry high temperature anaerobic fermentation equipment of straw with internal circulation of biogas slurry according to claim 8, characterized in that: It also includes a display interface (20), whose connection end is electrically connected to a controller (21), wherein the input end and the output end of the controller (21) are respectively provided with an A / D converter and a D / A converter, wherein the pH meter (601) and the radar level meter (602) are both electrically connected to the A / D converter, and the straw feed control valve (1), the biogas residue discharge control valve (13), the biogas liquid discharge control valve (8) and the biogas discharge control valve (18) are all electrically connected to the D / A converter.

10. A method for high temperature anaerobic fermentation of straw with internal circulation of biogas slurry, using the high temperature anaerobic fermentation equipment of straw with internal circulation of biogas slurry as claimed in any one of claims 1 to 9, characterized in that: The steps include: S1, controlling the heating facility (5) to perform cyclic heating, and feeding the straw from the gravity feeding pipeline (2) into the fermentation tank (4) under pressure, to the top of the hydrolysis zone (B); S2. Under the action of gravity and pressure, the straw passes through the hydrolysis zone (B), acidification and acid production zone (C), primary methane production zone (D) and secondary fermentation zone (E) in sequence, completing the hydrolysis, acidification and acid production and methane production processes respectively; S3, under the action of gravity and pressure, the water in the reaction material is squeezed out and enters the secondary fermentation area (E) through the secondary fermentation area sieve plate (14); driven by the generated methane gas, the biogas slurry in the secondary fermentation area (E) is lifted to the gas storage area (A) through the biogas slurry lifting pipe (15); S4, by changing the opening of the biogas discharge control valve (18), the internal pressure of the gas storage area (A) is adjusted to ensure that the flow rate of the biogas slurry in the secondary fermentation area (E) enters the gas storage area (A) along with the biogas; under the action of the internal pressure, part of the biogas slurry in the gas storage area (A) is sprayed onto the material in the hydrolysis area (B) through the sieve plate (3) of the gas storage area, and the other part is sprayed onto the material in the main methanogenic area (D) through the biogas slurry spraying mechanism, so as to adjust the bacterial colonies in the hydrolysis area (B) and the methanogenic area (D); S5, using the monitoring module (6) to obtain the material height in the fermentation tank (4) and the pH value of the generated biogas slurry, comparing them with the set threshold value, adjusting the opening of the straw feed control valve (1) and the biogas residue discharge control valve (13), so that the gravity feed pipeline (2) and the biogas residue discharge pipeline (12) are filled with materials; opening the biogas slurry discharge control valve (8) in a timely manner to discharge part of the biogas slurry or add bacterial agents to adjust the quality of the biogas slurry in the secondary fermentation area (E), and entering S6; S6, open the biogas slurry discharge control valve (8) and the biogas residue discharge control valve (13), discharge the fermented biogas slurry from the biogas slurry discharge pipeline (9), and discharge the biogas residue through the biogas residue discharge pipeline (12), and then cycle S1-S5.

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