CN108165478A - A kind of the effectively hydrolyzing acidization tool and its installation for fermenting of the suitable high solid content agricultural wastes of processing - Google Patents

Abstract

The invention discloses a kind of the effectively hydrolyzing acidization tool and its installation for fermenting of the suitable high solid content agricultural wastes of processing, including reactor for hydrolysis and acidification (1), hot water cyclesystem (2), percolate, biogas slurry spray regulating system (3), aerating system (4).The reactor for hydrolysis and acidification (1) is suitble to the high solid content agricultural wastes of processing, using the direct input and output material of forklift.The hot water cyclesystem (2) persistently provides heat source, mesophilic digestion for reactor.Regulating system (3) is sprayed using percolate (acidifying solution), biogas slurry reflux spray by percolate, biogas slurry, enhances material continued hydrolysis souring ability.Aerating system (4) provides micro- aerobic hydrolysis acidification environment, enhanced hydrolysis for hydrolysis acidification reaction.The present invention can be effectively improved using agricultural wastes as the continuous operation reactor input and output material of raw material is difficult, hydrolysis is vulnerable to the problems such as the sour feedback inhibition of production；Convenient for management, operation energy consumption is low, has preferable application prospect and promotional value.

Description

A high-efficiency hydrolysis acidification method suitable for treating agricultural waste with high solid content and its Fermentation device

technical field

The invention belongs to the field of biogas engineering, and is used for improving the hydrolysis and acidification efficiency in the two-phase anaerobic fermentation process using agricultural waste such as crop stalks, livestock and poultry manure, and tail vegetables as raw materials, especially for processing materials with high solid content The designed hydrolytic acidification method with spraying, leachate biogas slurry return and its device.

Background technique

The use of anaerobic fermentation to produce biogas is one of the main ways to promote the resource utilization of agricultural waste, and it is also an important way to promote the green development of agriculture and reduce non-point source pollution. Agricultural wastes are mainly crop straws, livestock and poultry manure, and end vegetables. During the anaerobic fermentation process, especially for fiber-rich raw materials such as crop straws and cow dung, hydrolysis is the rate-limiting step that affects the efficiency of biogas production. Moreover, the solid content of raw materials for anaerobic fermentation in my country is between 4% and 6%. Straw and livestock and poultry manure are easily blocked by pipelines. Floating and encrusting materials in the reactor seriously hinder the continuous operation of the actual project. For the current development of agricultural biogas projects in my country, it is necessary to select appropriate process methods and fermentation devices according to the characteristics of raw materials.

In order to solve the above problems, domestic countries generally follow the example of developed countries in Europe to adopt a two-phase anaerobic fermentation process, that is, two-phase separated hydrolytic acidification + anaerobic fermentation to produce biogas. However, due to the fact that the entire fermentation reaction is carried out under airtight conditions, and domestic straw (dry straw) and easily degradable substances of livestock and poultry manure are limited, resulting in low hydrolysis efficiency, lack of acidification products, and no significant improvement in gas production efficiency. Moreover, the construction and operation process is complicated to operate, and the input cost is relatively high, which still lacks application value. To this end, domestic and foreign scientific research teams have conducted a lot of research focusing on the problem, and developed a non-closed hydrolysis acidification reactor suitable for the treatment of agricultural waste according to the characteristics of raw materials and engineering operation characteristics, which can not only improve the hydrolysis rate through aeration, but also accelerate acidification products. The formation of the reactor, and the feeding and discharging are carried out in an open environment, which successfully avoids the problem of pipeline blockage and greatly improves the continuous operation capacity of the reactor. However, in the process of hydrolytic acidification, aeration will lose part of the acidification products, and the method of increasing the solid content can significantly promote the increase of organic acid concentration; The volume of the reactor is based on the energy-consuming stirring device to avoid crusting. This process has gradually attracted attention in domestic agricultural waste biogas projects.

Under the condition of high solid content (10-40%), the free water content is significantly reduced, resulting in a decrease in mass transfer performance and affecting the continuous hydrolysis and acidification of materials. Moreover, the solid content is high, the easily degradable components of the material quickly produce acid, and the feedback inhibition further limits the hydrolysis of the material. In addition, there is still a lack of scientific control measures and suitable equipment for intensifying the hydrolysis and acidification process of materials with high solid content, which is an urgent problem to be solved in the current development of agricultural waste hydrolysis and acidification technology and equipment.

Contents of the invention

In order to solve the above-mentioned engineering practical problems and overcome the deficiencies of the prior art, the present invention provides a high-efficiency hydrolysis acidification method and fermentation device suitable for treating agricultural waste with high solid content, especially through spraying and percolation to strengthen the high-solid content The continuous hydrolysis and acid production capacity of solid rate materials can continuously supply sufficient acidification products for anaerobic fermentation to produce biogas.

The technical scheme adopted in the present invention is:

A high-efficiency hydrolysis and acidification method suitable for treating agricultural wastes with high solid content. The operation steps are that the agricultural wastes such as crop straws, livestock and poultry manure, and tail vegetables are fully mixed in advance, and are fed by a forklift or an automatic feeder (conveyor belt) Enter the hydrolysis acidification reactor (1). Close the feed door of the reactor, and open the hot water circulation system (2) to supply heat to the reactor. At the same time, the leachate and biogas slurry spray adjustment system (3) is turned on for material spraying, and the spray liquid is the leachate and biogas slurry mixture discharged from the anaerobic fermentation reactor, which enters the leachate collection tank for storage through percolation. At the same time, the output provides acidified products for the anaerobic fermentation reactor. During the hydrolytic acidification process, the aeration system (4) is turned on and off at regular intervals to aerate the material.

Further, the hydrolysis acidification reactor (1) is suitable for processing crop straws, and the solid content of the material is 10%-40%, preferably 30%. Livestock and poultry manure is used to adjust the carbon-nitrogen ratio (20-30:1) and serve as an inoculum. The mixing ratio of straw and livestock and poultry manure dry matter is 3:7-7:3, preferably 6:4. The material solid residence time is 5-15 days, preferably 9 days. After 9 days, the material is transported out of the hydrolytic acidification reactor (1) by a forklift, and a new batch of raw materials is replaced. The discharged material can be considered as an organic fertilizer or a seedling-raising substrate because of its high solid content.

Further, the hot water circulation system (2) provides a heat source for the reactor through the biogas boiler, and when the material enters the hydrolysis acidification reactor (1), close the grille and the material inlet and outlet door, and open the hot water circulation system ( 2), the hydrolysis and acidification temperature is controlled at 25°C to 55°C, preferably 35°C.

Further, the leachate and biogas slurry spray adjustment system (3) circulates the leachate and biogas slurry through spraying and percolation. Pre-set the leachate and biogas slurry spray adjustment system (3), the spray frequency is 3 to 12 times/day, preferably 6 times/day, after the leachate (acidification liquid) is collected, a part of it enters the back-end anaerobic quantitatively The fermentation reactor produces biogas, and the other part can be returned to the spray pipe to spray the material. After the leachate enters the anaerobic fermentation reactor, the same amount of biogas slurry is discharged, and the liquid after solid-liquid separation returns to the hydrolysis acidification reactor (1) through the leachate and biogas slurry spray regulation system (3). ) to spray the material. The spray liquid is a mixture of leachate and biogas slurry, and the mixing ratio is adjusted according to the pH of the material during the hydrolysis and acidification process. The mixing ratio of leachate (acidified liquid) and biogas slurry is sprayed and adjusted according to the pH value of the liquid sprayed out from the spray head to be 6.0-7.0, preferably pH 6.5.

Further, the aeration system (4), the hydrolytic acidification reactor (1) is provided with an aeration system (4), the aeration system needs to maintain a micro-aerobic state, and the aeration frequency is set according to the concentration of liquid dissolved oxygen in the leachate collection tank. Determined, the dissolved oxygen concentration needs to be kept at 0.2-2 mg/L, preferably 1 mg/L.

A high-efficiency hydrolysis and acidification device suitable for treating agricultural waste with high solid content, including hydrolysis and acidification reactor (1), hot water circulation system (2), leachate, biogas slurry spray regulation system (3) and aeration system (4).

Further, the hydrolytic acidification reactor (1) is a garage-type structure, the side wall is a concrete structure, divided into inner and outer layers, the interlayer is covered with hot water heating coils, and the outer wall is wrapped with thermal insulation materials, preferably polyurethane foam Material. The interior is divided into a material reaction area and a leachate collection pool by a screen. Wherein, the material reaction zone is located on the ground, and the leachate collection tank is below the ground. The spraying facility vertically runs through the material reaction zone and the leachate collection tank, is distributed twice on the left and right of the material inlet and outlet door and is close to the side wall, and the spraying is controlled by a submersible pump. The aeration device is located in the leachate collection tank, and the upper cover of the hydrolysis acidification reactor can be opened to assist aeration. The discharge port is located at the lower part of the leachate collection tank, and the leachate (acidified liquid) enters the anaerobic fermentation reactor through the leachate discharge pipe.

Further, the hot water circulation system (2) is composed of a biogas boiler, a water outlet pipe, and a water return pipe connected to the heating coil, and the gate valve is used to control the water flow.

Further, the leachate and biogas slurry spray adjustment system (3) is located in the hydrolysis acidification reactor, and the stainless steel material is distributed left and right according to the direction of the inlet and outlet doors and extends inwards in rows, and the distance must ensure that the surface of the material is sprayed. Evenly, the submersible pump in the leachate collection tank is connected to the spray pipeline and the anaerobic fermentation output liquid return pipeline, and the radiation radius of the nozzle is 30-70cm, preferably 50cm.

Further, the aeration device of the aeration system (4) is made of stainless steel, distributed on the left and right sides facing the direction of the inlet and outlet doors, the upper part is a disc-shaped structure, and is close to the surface of the material, embedded in the screen, Three rows of spraying devices are provided with one set of aeration devices, and at the same time, the upper cover of the hydrolysis acidification reactor (1) has an automatic control opening function for ventilation and aeration.

Compared with the prior art, the present invention has the following advantages or positive effects:

(1) Simple operation and low input cost. The overall process design is compact, fully considering the disadvantages of the traditional two-phase anaerobic fermentation process, especially the shortcomings of the hydrolytic acidification process. Among them, the hydrolytic acidification reactor (1) fully considers the characteristics of agricultural waste rich in fibers and the impact of high solid content materials on the actual operation of the project. The invention removes the traditional pipeline or screw pump feeding and discharging method, designs the feeding and discharging bin door, realizes the large-scale feeding and discharging of raw materials through a forklift or an automatic feeding device, has strong operability, and improves production efficiency.

(2) The overall design fully considers the continuous enhancement of the continuous hydrolysis and acidification capacity of materials, and reduces the occurrence of feedback inhibition in the hydrolysis and acidification process of materials with high solid content. The mass transfer effect is increased by adjusting the spraying method, and the acidification products generated in the material reaction zone are removed in a timely manner by percolation to strengthen acid production. Moreover, the microaerobic environment is created by aeration to improve the hydrolysis efficiency. Compared with the traditional process, the continuous hydrolysis and acidification capacity of the system is greatly improved.

(3) Low energy consumption in continuous operation. The biogas boiler is used to supply heat to the hydrolysis and acidification reactor, and the leachate and biogas slurry spray adjustment system (2) is designed to assist in increasing the temperature of materials and reduce energy consumption. Moreover, the hydrolytic acidification reactor (1) does not need stirring, and the mass transfer efficiency is improved by spraying leachate and biogas slurry. The open inlet and outlet reduce the use of pumps, and the energy consumption is significantly saved.

(4) High safety, reducing the emission of greenhouse gases. Aeration not only accelerates the hydrolysis of materials, but also inhibits the growth of methanogens and controls the generation and emission of methane gas. In addition, the upper cover of the hydrolysis acidification reactor (1) can be opened to accelerate the discharge of CO ₂ , which is conducive to the safety of manpower entry and exit during discharge. The non-airtight design of the hydrolytic acidification reactor (1) also reduces the risk of explosion.

(5) It is more convenient to expand the efficient recycling mode of agricultural waste resource utilization. On the one hand, the material of the hydrolytic acidification reactor (1) has been sprayed, aerated, etc. to improve the degree of maturity, and after being discharged, it can be directly used for composting to produce organic fertilizer or to make a seedling raising substrate. On the other hand, the discharge of biogas slurry is reduced through backflow spraying and percolation, and secondary pollution is avoided. The amount of biogas slurry is limited and can be used to make biopesticides, foliar fertilizers, etc.

Description of drawings:

Figure 1 is a diagram of a high-efficiency hydrolysis acidification device suitable for treating agricultural waste with high solid content.

Detailed ways:

A sequencing batch anaerobic dry fermentation device with enhanced warming function:

The raw material is crop straw, mixed with cow dung, the dry matter mixing ratio is 6:4, the solid content is 30%, and the hydrolysis and acidification is started at 35°C. The spray frequency is set to 6 times/day, and each spray is 3min. The leachate (acidified liquid) is quantitatively discharged according to the hydraulic retention time of the anaerobic fermentation device, and the acidified product is provided for the anaerobic fermentation device. The ratio of leachate (acidified liquid) and biogas slurry in the spraying process should be prepared according to the pH of 6.5. The intermittent aeration method is adopted, and the aeration frequency is set according to the dissolved oxygen concentration of the liquid in the leachate collection tank. The dissolved oxygen concentration is controlled at 1 mg/L during the hydrolysis and acidification process. The upper cover of the hydrolysis and acidification reactor can also be opened to assist in the adjustment of the dissolved oxygen concentration. During continuous operation, the concentration of organic acid in the system is 8000-160000 mg/L, and the degradation rate of dry matter of materials is 20-30%.

Hydrolysis and acidification reactor (1): the material enters the material reaction zone (102) from the inlet and outlet door (101), and a screen (103) is installed on the ground, and the lower part is a leachate collection tank (104), and the collected leachate is passed through The liquid outlet (105) enters the feed (acidification liquid) pipeline (106), and is controlled by the feed pump (107) to enter the anaerobic fermentation system. The material reaction zone (102) is provided with a grid (108), which is pulled up after feeding to prevent the material from being scattered. The upper cover (109) of the hydrolysis acidification reactor has an automatic control opening and closing function. When it is closed, the generated gas escapes from the outlet pipe (110). The side wall of the hydrolytic acidification reactor has a double-layer concrete wall (111) structure, a hot water heating coil (112) is embedded inside, and an insulating material (113) is wrapped on the outside of the side wall. A pH meter (114) is inserted into the spray pipe (301) through the side wall, and a dissolved oxygen concentration detector (115) is located at the bottom of the leachate collection tank (104).

Hot water circulation system (2): The biogas boiler (201) provides heat source for the hydrolysis acidification reactor (1). The outlet water is connected to the hot water heating coil (114) in the hydrolysis acidification reactor (1) through the boiler outlet pipe (202). The other end of the hot water heating coil (114) is connected to a boiler outlet pipe and enters the biogas boiler (201) for circulation and heating. The hot water flow rate is controlled by gate valve (204).

Leachate and biogas slurry spray adjustment system (3): The spray pipe (301) is located on the left and right sides of the inlet and outlet gate (101) of the hydrolysis acidification reactor (1), close to the side wall (113), and Arranged in rows. The submersible pumps (302) on the left and right sides are responsible for the circular spraying of leachate (acidification liquid) and biogas slurry. The sprinkler heads (303) are located above the material and arranged in the center, and the distance is arranged on the principle of spraying the material evenly.

Aeration system (4): the aeration pipe (401) is located in the leachate collection tank (104) of the hydrolysis acidification reactor (1), close to the submersible pump (302), and the upper part is close to the material to install the aeration disc (402) , inlaid inside the screen (103), and one set of aeration devices is set for every three rows of spraying facilities.

Claims (7)

1. A high-efficiency hydrolysis acidification method and fermentation device thereof suitable for processing agricultural waste with high solid content, characterized in that it comprises the steps carried out in the following order: 1) The materials are pre-mixed evenly and then sent into the hydrolysis acidification reactor (1), distributed evenly, and the grille (108) and the material inlet and outlet door (101) are closed; 2) Turn on the hot water circulation system (2), supply heat for the hydrolysis acidification reactor (1), and keep the temperature constant; 3) Turn on the leachate and biogas slurry spray adjustment system (3), use the leachate (acidified liquid) produced by the hydrolysis acidification reactor (1) and the biogas slurry after the solid-liquid separation of the anaerobic fermentation output as the material spray shower; 4) During the hydrolysis and acidification process, the aeration system (4) is controlled to aerate the material. At the same time, the upper cover (109) of the hydrolysis acidification reactor (1) is opened at a certain angle to form a non-closed hydrolysis acidification reaction system and create a slightly aerobic hydrolysis acidification environment. 2. A kind of high-efficiency hydrolytic acidification method suitable for processing agricultural waste with high solid content as claimed in claim 1, characterized in that, the hydrolytic acidification reactor (1) is used to process crop stalks, and the solid content of the material is 10% to 40%, preferably 30%. Use livestock and poultry manure to adjust the carbon-nitrogen ratio (20-30:1), and also play the role of inoculating straw. The dry matter ratio of straw and livestock and poultry manure is 3:7-7:3, preferably 6:4. The material solid residence time is 5-15 days, preferably 9 days. 3. A kind of high-efficiency hydrolytic acidification method suitable for processing agricultural wastes with high solid content as claimed in claim 1, characterized in that, after the material enters the hydrolytic acidification reactor (1), the grid and the inlet and outlet are closed. The material door is opened to open the hot water circulation system (2), and the hydrolysis and acidification temperature is controlled at 25°C to 55°C, preferably 35°C. 4. A high-efficiency hydrolysis and acidification method suitable for treating agricultural waste with high solid content as claimed in claim 1, characterized in that the hydrolysis and acidification process requires quantitative spraying of materials, and the leachate and biogas slurry spraying adjustments are set System (3), the spraying frequency is 3-12 times/day, the spraying time is 1-5min, preferably 6 times/day, each spraying is 3min, the leachate (acidification liquid) is collected and quantitatively enters the back-end anaerobic Fermentation reactor, at the same time, the same amount of biogas slurry that is discharged is returned to the material reaction zone of the hydrolysis acidification reactor (1) for spraying through the leachate and biogas slurry spray adjustment system (3), or returned to the leachate Stored in the collection tank, the mixing ratio of the leachate (acidified liquid) and biogas slurry used for spraying is preferably 6.0-7.0 according to the pH of the liquid sprayed by the spray head, and the pH is preferably 6.5. 5. a kind of hydrolytic acidification method that is suitable for processing agricultural waste with high solid content as claimed in claim 1, is characterized in that, described hydrolytic acidification reactor (1) is provided with aeration system (4), and aeration frequency According to the dissolved oxygen concentration setting of the liquid in the leachate collection tank (104), the dissolved oxygen concentration needs to be kept at 0.2-2 mg/L, preferably 1 mg/L. 6. A high-efficiency hydrolysis and acidification device suitable for treating agricultural waste with high solid content, characterized in that it includes a hydrolysis and acidification reactor (1), a hot water circulation system (2), a leachate, and a biogas slurry spray system (3) , Aeration system (4). 7. A kind of high-efficiency hydrolysis acidification device suitable for processing agricultural waste with high solid content as claimed in claim 6, characterized in that, the side wall of the hydrolysis acidification reactor (1) is a concrete structure, and the interlayer cloth in the side wall There is a hot water heating coil, which is supplied with heat by the hot water circulation system (2), and the outer wall is wrapped with thermal insulation material, preferably polyurethane foam material. The internal leachate and biogas slurry spray system (3) is arranged in rows on the left and right sides in the direction facing the inlet and outlet doors. The radiation radius of the nozzles is 30-70cm, preferably 50cm. The upper and lower parts of the hydrolysis acidification reactor are equipped with submersible pumps to transport leachate and biogas slurry to the material reaction area and leachate collection pool. The leachate collection pool is built below the ground, and the material reaction area is located above the ground and separated by a screen. . The aeration system (4) has an aeration device close to the bottom of the material and is located on the left and right sides of the material inlet and outlet direction. One set of aeration device is installed for every three rows of spray pipes. At the same time, the upper cover of the hydrolysis acidification reactor (1) has an automatic Adjust the opening function to ventilate and aerate the material.