A high-oil co-digestion anti-shock retrofit device and method for an existing anaerobic digester

Abstract

The application belongs to the technical field of organic solid waste resource utilization and anaerobic digestion, and particularly relates to a high-oil co-digestion anti-impact retrofit device and method for an existing anaerobic digestion tank, which comprises an anaerobic digestion tank and a high-oil degradation buffer structure; an adjustable overflow weir, a biochar filler bed and an electrically-controlled knife gate valve are arranged in the high-oil degradation buffer structure; a municipal sludge feeding port, a high-oil organic waste feeding pipe, a discharge pipe and an exhaust pipe are arranged on the anaerobic digestion tank; the municipal sludge feeding port is communicated with the upper part of the inner cavity of the anaerobic digestion tank, and the discharge pipe is communicated with the bottom of the inner cavity of the anaerobic digestion tank. The high-oil material sequentially undergoes inoculation and dilution, bottom feeding, upward circulation, pulse mixing, standing and floating, biochar interception and degradation promotion, weir control and slow release and double-valve slag locking and discharge, so that short-time high-oil impact is converted into controllable continuous load, thereby improving the stability and anti-impact capacity of the existing anaerobic digestion tank for co-digestion of high-oil organic waste.

Description

Technical Field

[0001] This invention relates to a device and method for shock-resistant modification of existing anaerobic digesters with high-oil co-digestion, belonging to the field of organic solid waste resource utilization and anaerobic digestion technology. Background Technology

[0002] Food waste, oily sludge, grease waste, and grease processing waste liquid, among other high-oil organic wastes, have high organic matter content and methanogenic potential. Co-anaerobic digestion of these wastes with substrates such as municipal sludge can improve the resource and energy utilization of organic solid waste. However, anaerobic digestion of high-oil organic wastes cannot simply achieve stable gas production by increasing the organic load. Oils exhibit significant buoyancy and hydrophobicity in anaerobic systems, easily forming localized oil films, oil clumps, or scum after entering the reactor. Furthermore, long-chain fatty acids produced by oil hydrolysis may accumulate in localized areas and inhibit methanogenic bacteria activity, leading to increased volatile fatty acid levels, decreased pH, fluctuating gas production, and even system acidification.

[0003] In existing technologies, the co-anaerobic digestion of food waste and sludge typically employs a technical route involving external screening, crushing, pulping, sand removal, oil-water separation, and external buffering or homogenization before the waste enters the anaerobic digestion system. While this approach improves feed homogeneity and reduces the impact of some impurities, the following problems still exist: First, external pretreatment and external buffer equipment are costly to build and occupy a large area, making them unsuitable for low-cost retrofitting of some existing anaerobic digesters, especially in townships or small and medium-sized co-digestion systems, where mature and dedicated oil removal measures and equipment are not yet perfect. Secondly, while oil-water separation or degreasing can reduce the impact of oils, it also weakens the energy utilization value of the oils themselves. Third, external pretreatment is difficult to solve the problems of local floating, short-term oil load peak and local inhibition of long-chain fatty acids that occur when high-oil materials enter the existing anaerobic digester. Fourth, ordinary buffer structures, ordinary packed beds, ordinary stirring devices, or ordinary overflow ports are mostly isolated components, lacking a coordinated operation method around the "floating-interception-promoting degradation-slow release-slag discharge" of high-oil materials. Summary of the Invention

[0004] The purpose of this invention is to address the problems existing in the prior art by providing a device and method for modifying existing anaerobic digesters to withstand high oil co-digestion. This invention retains the utilization of oil resources, reduces high oil impact, and ensures the controllable discharge of heavy impurities.

[0005] The technical solution provided by the present invention to solve the above-mentioned technical problems is: a high-oil co-digestion shock-resistant modification device for existing anaerobic digesters, including an anaerobic digester and a high-oil degradation buffer structure vertically arranged at the top of the inner cavity of the anaerobic digester; The high-oil degradation buffer structure is divided into an upper oil interception and degradation promotion zone, a middle circulation buffer zone, a lower inoculation feeding zone, and a bottom slag locking zone from top to bottom. The upper oil interception and degradation promotion zone is equipped with an adjustable overflow weir and a biochar packing bed. The bottom slag locking zone is equipped with an electrically controlled knife gate valve. The anaerobic digester is equipped with a municipal sludge inlet, a high-oil organic waste inlet pipe, an outlet pipe, and an exhaust pipe; the exhaust pipe is connected to the upper oil interception and degradation zone, the high-oil organic waste inlet pipe is connected to the lower inoculation inlet zone, the municipal sludge inlet is connected to the upper part of the inner cavity of the anaerobic digester, and the outlet pipe is connected to the bottom of the inner cavity of the anaerobic digester. The high-oil degradation buffer structure is equipped with a stirring device, the upper end of which extends out of the top of the anaerobic digester, and the lower end is located in the middle circulation buffer zone.

[0006] A further technical solution is to install a stirring paddle in the main digester inside the anaerobic digester.

[0007] A further technical solution is that the high-oil degradation buffer structure is a vertical cylindrical structure, a vertical box-shaped structure, an upper cylindrical and lower conical structure, or an irregularly shaped structure adapted to the internal space of the anaerobic digester.

[0008] A further technical solution is that a reflux inoculation branch is provided between the discharge pipe and the high-oil organic waste inlet pipe; the reflux inoculation branch includes a reflux pipe and a mixer; both ends of the reflux pipe are connected to the discharge pipe and the mixer respectively, one end of the high-oil organic waste inlet pipe is connected to the mixer, and the mixer is provided with an external high-oil organic waste inlet pipe.

[0009] A further technical solution is that the biochar packing bed includes an oil interception buffer layer and a biodegradation promoting layer from top to bottom; the oil interception buffer layer uses larger particle size biochar packing material, with a particle size of 20-50 mm, to reduce the risk of clogging and to initially intercept and disperse large oil droplets or oil clumps; the biodegradation promoting layer uses smaller particle size biochar packing material, with a particle size of 5-20 mm, to provide a larger microbial attachment area and enrich functional bacterial groups tolerant to long-chain fatty acids.

[0010] A further technical solution is that the adjustable overflow weir includes an overflow weir body, on which three sets of overflow holes are arranged at the top, middle and bottom. Each overflow hole includes several horizontally arranged overflow holes. An electrically controlled gate is provided inside each overflow hole. A guide rail that cooperates with the electrically controlled gate is provided on the overflow weir body. The electrically controlled gate is slidably installed in the guide rail. When the electrically controlled gate is opened, it slides upward along the guide rail to expose the overflow holes. When closed, it slides downward along the guide rail to block the overflow holes.

[0011] A further technical solution is that the bottom slag-locking zone includes a conical shrinking structure and a slag-locking cavity communicating with the bottom of the conical shrinking structure, and an electrically controlled knife gate valve is respectively installed at the upper and lower ends of the slag-locking cavity.

[0012] A method for shock-resistant modification of existing anaerobic digesters for high-oil co-digestion specifically includes the following steps: A. Obtain the feed amount and oil content of high-oil organic waste, and obtain at least two operating parameters from the following: volatile fatty acid concentration, pH, alkalinity, gas production rate fluctuation, methane content change, and liquid level in the high-oil degradation buffer structure within the anaerobic digester. B. Based on the parameters in step A, switch the system to one of the following modes: steady-state co-digestion mode, peak shaving and slow release mode, or high oil shock protection mode. C. Part of the digested sludge discharged from the discharge pipe is led out through the return inoculation branch and mixed with high-oil organic waste according to the return inoculation ratio corresponding to the system mode to form a high-oil mixture after inoculation and dilution. D. Input the high-oil mixture into the bottom of the high-oil degradation buffer structure through the high-oil organic waste feed pipe; E. Control the stirring device to form a bottom-up circulating flow, so that the high oil mixture can be buffered and dispersed in the high oil degradation buffer structure, and the oil droplets can migrate to the biochar packing bed along the floating path. F. The floating oil droplets are adsorbed, trapped and dispersed at the biochar packing bed, and biodegraded by the microorganisms attached to the biochar packing bed. G. Adjust the height of the adjustable overflow weir according to the high oil shock risk level, so that the buffered material enters the main digestion zone at a release rate corresponding to the high oil shock risk level. H. The municipal sludge is fed into the main digestion zone of the anaerobic digester through the municipal sludge inlet. The material in the main digestion zone continues to be anaerobically digested under the action of the stirring device in the main digestion tank. The digested material is discharged through the discharge pipe, and the biogas generated is discharged through the exhaust pipe. I. Heavy impurities deposited at the bottom of the high-oil degradation buffer structure are allowed to enter the slag-locking chamber and are intermittently isolated and discharged through the timed opening and closing of two electrically controlled knife gate valves.

[0013] A further technical solution is that, in step B, when the feed load of high-oil organic waste is within a preset low load range, and the pH, volatile fatty acid concentration, and gas production rate of the main digestion zone are all within a stable range, it is determined to be a steady-state co-digestion mode. When the feed load of high-oil organic waste increases, or when any of the following phenomena occur in the main digestion zone: increased concentration of volatile fatty acids, decreased pH, or fluctuation in gas production rate, it is determined to be peak-shaving and slow-release mode. When the feed load of high-oil organic waste exceeds the preset high load range, or when at least two of the following phenomena occur simultaneously in the main digestion zone: increased volatile fatty acid concentration, decreased pH, and decreased gas production rate, it is determined to be in high-oil shock protection mode.

[0014] A further technical solution is that the recirculation inoculation ratio of the partially digested sludge to the high-oil organic waste is coordinated with the preset overflow height of the adjustable overflow weir; In step G, when the risk level of high oil shock increases, the reflux inoculation ratio is increased and the adjustable overflow weir is switched to a higher preset overflow height to enhance the inoculation dilution effect and prolong the residence time of the high oil mixture; when the risk level of high oil shock decreases, the reflux inoculation ratio is decreased and the adjustable overflow weir is switched to a lower preset overflow height to increase the release rate. The volume ratio of the partially digested sludge to the high-oil organic waste is 1:1 to 5:1; wherein, in the steady-state co-digestion mode, it is 1:1 to 2:1, in the peak-shaving and slow-release mode, it is 2:1 to 4:1, and in the high-oil shock protection mode, it is 4:1 to 5:1.

[0015] The present invention has the following beneficial effects: First, this invention combines the existing high-oil degradation buffer structure inside the anaerobic digester with a special operating method. Instead of relying solely on external oil removal or pretreatment, it completes the peak reduction, slow release, and accelerated degradation of high-oil materials inside the anaerobic digester, which is beneficial for preserving the energy utilization value of oils.

[0016] Secondly, the present invention uses a closed inoculation and dilution path—discharge pipe—return inoculation branch—high-oil organic waste feed pipe—to mix high-oil organic waste with part of the digested sludge before it enters the high-oil degradation buffer structure, thereby reducing the local instantaneous oil concentration and increasing the inoculation intensity of functional microorganisms.

[0017] Third, the present invention, through bottom feeding and rising circulating flow field, forces high-oil materials to pass through the middle circulating buffer zone and the upper oil interception and degradation zone from bottom to top, reducing the possibility of short-flow entering the main digestion zone.

[0018] Fourth, the present invention places the biochar packing bed between the oil droplet floating path and the adjustable overflow weir, so that the floating oil droplets are adsorbed, intercepted, dispersed and degraded before approaching the overflow area, thus avoiding the floating oil from directly entering the main digestion zone under ordinary overflow structures.

[0019] Fifth, the present invention uses a control unit to coordinate and control the reflux inoculation ratio, stirring mode, overflow hole group opening and closing status and slag discharge procedure, so that multiple components work together around the same high oil impact risk level, rather than operating in isolation, thereby enhancing the synergistic effect between structural and method features.

[0020] Sixth, the present invention sets up a steady-state co-digestion mode, a peak-shaving and slow-release mode, and a high-oil impact protection mode. Under different high-oil loads and main digestion zone operating conditions, different reflux ratios, stirring rhythms, and overflow heights are adopted to transform the short-term impact of high-oil materials into a controllable continuous load.

[0021] Seventh, this invention achieves the step-by-step isolation and discharge of heavy impurities through a conical shrinkage structure, a slag-locking chamber, and an interlocking electrically controlled knife gate valve, thereby reducing the impact of bone residue, sand particles, and shell fragments in high-oil kitchen waste and other materials on long-term operational stability.

[0022] Eighth, the inventive point of this invention lies in the overall coordination of "structure-control-operation method", namely, the reflux inoculation branch is responsible for front-end inoculation and dilution, the device structure stirring paddle is responsible for upward circulation and pulse mixing, the biochar packing bed is responsible for oil phase interception and bio-promoted degradation, the adjustable overflow weir is responsible for residence time and release rate regulation, and the dual-valve slag-locking system is responsible for the closed discharge of heavy impurities. All the structures cooperate with each other under the staged operation method to jointly achieve the high oil co-digestion and shock resistance effect. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of a high-oil co-digestion shock-resistant modification device for existing anaerobic digesters according to the present invention; Figure 2 This is a top view of a high-oil co-digestion shock-resistant modification device for an existing anaerobic digester according to the present invention; Figure 3 This is a partially enlarged cross-sectional view of the multi-stage overflow orifice type adjustable overflow weir of the present invention.

[0024] The diagram shows: 1. Anaerobic digester; 2. High-oil degradation buffer structure; 3. Biochar packing bed; 4. Adjustable overflow weir; 5. Stirring device; 6. Main digester stirring paddle; 7. Electrically controlled knife gate valve; 8. Sludge locking chamber; 9. Municipal sludge inlet; 10. High-oil organic waste inlet pipe; 11. Discharge pipe; 12. Exhaust pipe; 13. Feed pump; 14. Return pump; 15. Mixer; 16. High-oil organic waste external inlet pipe; 17. Return pipe; 41. Seal; 42. Overflow hole; 43. Electrically controlled gate valve; 44. Guide rail. Detailed Implementation

[0025] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0027] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can also refer to a mechanical connection. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0028] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0029] like Figure 1 As shown, the present invention provides a high-oil co-digestion shock-resistant modification device for existing anaerobic digesters, including an anaerobic digester 1 and a high-oil degradation buffer structure 2 vertically arranged at the top of the inner cavity of the anaerobic digester 1. The inner cavity of the anaerobic digester 1 is the main digestion zone, and the high-oil degradation buffer structure 2 forms a partitioned structure with the main digestion zone that is internally connected but with controlled release. The high-oil degradation buffer structure 2 is divided into an upper oil interception and degradation promotion zone, a middle circulation buffer zone, a lower inoculation and feeding zone, and a bottom slag locking zone from top to bottom. The upper oil interception and degradation zone is equipped with an adjustable overflow weir 4 and a biochar packing bed 3. The biochar packing bed 3 is located between the upward path of oil droplets in the high-oil material and the adjustable overflow weir 4, so that the upward oil droplets are intercepted, dispersed and biodegraded before approaching the adjustable overflow weir 4. The adjustable overflow weir 4 is used to adjust the liquid level of the high-oil degradation buffer structure 2, the material residence time and the release rate from the high-oil degradation buffer structure 2 to the main digestion zone in the anaerobic digester 1. An electrically controlled knife gate valve 7 is installed in the bottom slag-locking zone; The anaerobic digester 1 is equipped with a municipal sludge inlet 9, a high-oil organic waste inlet pipe 10, a discharge pipe 11, and an exhaust pipe 12. The exhaust pipe 12 is connected to the upper oil interception and degradation zone, and the high-oil organic waste inlet pipe 10 is connected to the lower inoculation inlet zone, so that the high-oil organic waste (which is one or more of high-oil kitchen waste, oily sludge, grease waste, grease processing waste liquid, oily waste from livestock and poultry slaughter, or other high-oil organic waste) enters from the bottom or near-bottom area of ​​the high-oil degradation buffer structure 2. The municipal sludge inlet 9 is connected to the upper part of the inner cavity of the anaerobic digester 1, and the discharge pipe 11 is connected to the bottom of the inner cavity of the anaerobic digester 1. The high-oil degradation buffer structure 2 is equipped with a stirring device 5. The upper end of the stirring device 5 extends from the top of the anaerobic digester 1, and the lower end is located in the middle circulation buffer zone. The stirring device 5 is preferably located below the biochar packing bed 3. Its stirring direction, blade angle, rotation speed, or start-stop mode is configured to form an upward circulating flow field from the lower inoculation feeding zone to the upper oil interception and degradation zone. This upward circulating flow field disperses the high-oil mixture input from the bottom and ensures full contact with the anaerobic sludge in the buffer structure, and then promotes the oil droplets to migrate upward along the floating path.

[0030] The working process of this device is as follows: municipal sludge enters the main digestion zone through the municipal sludge feed pipe 9, and high-oil organic waste enters the lower inoculation feed zone of the high-oil degradation buffer structure 2 through the high-oil organic waste feed pipe 10. Therefore, the high-oil organic waste does not directly impact the main digestion zone, but must instead pass through the upper oil-blocking and degradation-promoting zone and the middle circulation buffer zone within the high-oil degradation buffer structure 2 from bottom to top, undergoing circulation buffering, oil-blocking, and degradation-promoting zones before entering the main digestion zone. Simultaneously, the biogas generated is discharged through the exhaust pipe 12; the digested material is discharged through the discharge pipe 11.

[0031] In this embodiment, the anaerobic digester 1 is equipped with a main digester stirring paddle 6. The main digester stirring paddle 6 and the high oil degradation buffer structure stirring paddle 5 are set independently, or they are set at different heights on the same stirring shaft; the anaerobic digester 1 is an egg-shaped anaerobic digester, a cylindrical anaerobic digester, or other closed anaerobic digestion reactor.

[0032] In this embodiment, the high-oil degradation buffer structure 2 is a vertical cylindrical structure, a vertical box-shaped structure, a cylindrical upper part and a conical lower part, or an irregularly shaped structure adapted to the internal space of the anaerobic digester 1. The high-oil degradation buffer structure 2 and the main digestion zone of the anaerobic digester 1 are located in the same anaerobic sealed environment, but the speed at which material enters the main digestion zone from the high-oil degradation buffer structure 2 is controlled by the adjustable overflow weir 4.

[0033] In this embodiment, a reflux inoculation branch is provided between the discharge pipe 11 and the high-oil organic waste inlet pipe 10; the reflux inoculation branch is used to mix the partially digested sludge drawn from the discharge pipe 11 with the high-oil organic waste before entering the high-oil degradation buffer structure 2, forming a high-oil mixture after inoculation dilution, and avoiding the floating oil phase from being completely emulsified and directly entering the main digestion zone, wherein the volume ratio of the partially digested sludge to the high-oil organic waste is 1:1 to 5:1.

[0034] Some of the digested sludge simultaneously acts as inoculum, dilution medium, and buffer medium: on the one hand, it introduces functional microbial communities that have adapted to the anaerobic digestion environment; on the other hand, it reduces the instantaneous oil concentration when high-oil organic waste enters the buffer structure; and on yet another hand, it ensures that high-oil materials have good compatibility with the anaerobic system before entering the buffer structure.

[0035] The reflux inoculation branch includes a reflux pipe 17 and a mixer 15; the two ends of the reflux pipe 17 are respectively connected to the discharge pipe 11 and the mixer 15, and one end of the high-oil organic waste feed pipe 10 is connected to the mixer 15. The mixer 15 is provided with an external feed pipe 16 for high-oil organic waste; during operation, some digested sludge is led out from the discharge pipe 11, transported to the mixer by the reflux pump, and mixed with the high-oil organic waste before entering the high-oil organic waste feed pipe 10 together.

[0036] In this embodiment, in order to better mix the partially digested sludge with the high-oil organic waste, the preferred embodiment is that the mixer 15 is equipped with a stirring device for stirring the mixture of the partially digested sludge and the high-oil organic waste.

[0037] In this embodiment, the device also includes an operation control unit, which is connected or signal-associated with the reflux inoculation branch, the stirring device 5, the adjustable overflow weir 4 and the electrically controlled knife gate valve 7, respectively, and is used to adjust the reflux inoculation ratio, stirring mode, weir top height and slag discharge procedure in conjunction with the oil load of high oil material and the operating status of the main digestion zone. The operation control unit can determine the high oil shock risk level based on at least two parameters among the high oil organic waste feed amount, oil content, volatile fatty acid concentration in the main digestion zone, pH, alkalinity, gas production rate fluctuation, methane content change, and liquid level in the high oil degradation buffer structure 2, and switch the system to steady-state co-digestion mode, peak shaving and slow release mode, or high oil shock protection mode.

[0038] In the steady-state co-digestion mode, the volume ratio of partially digested sludge to high-oil organic waste can be controlled at 1:1 to 2:1. The overflow weir 4 can be adjusted to a lower weir crest height, and the stirring device 5 operates in a continuous low-intensity or intermittent low-intensity mode, so that the high-oil mixture continuously passes through the biochar packing bed 3 and enters the main digestion zone.

[0039] In peak shaving and slow release mode, the volume ratio of partially digested sludge to high-oil organic waste can be controlled at 2:1 to 4:1. The overflow weir 4 can be adjusted to a medium weir crest height. The stirring device 5 performs pulse stirring-low speed maintenance-weir controlled release flow circulation to increase the contact time between the high-oil mixture and the biochar packing bed 3, thereby reducing short-term oil load peaks.

[0040] In the high-oil impact protection mode, the volume ratio of partially digested sludge to high-oil organic waste can be controlled at 4:1 to 5:1. The adjustable overflow weir 4 is raised to a higher weir crest height, and the stirring device 5 performs a periodic operation process of pulse mixing—static floating—packing interception—slow release. In this mode, pulse mixing first disperses the high-oil material at the bottom and brings it into contact with the inoculated sludge; then the stirring intensity is reduced or stopped, allowing oil droplets to migrate to the upper part of the liquid level and be enriched, intercepted, and degraded at the biochar packing bed 3; then the adjustable overflow weir 4 allows the buffered material to enter the main digestion zone at a lower rate.

[0041] In this embodiment, the biochar packing bed 3 is disposed within a detachable packing frame, which includes an upper anti-buoyancy limiting net, a lower supporting net, and lateral guide holes or guide slots; specifically, it includes an oil interception buffer layer and a biodegradation promoting layer from top to bottom; the oil interception buffer layer uses larger particle size biochar packing, with a particle size of 20-50 mm, to reduce the risk of clogging and to initially intercept and disperse large oil droplets or oil clumps; the biodegradation promoting layer uses smaller particle size biochar packing, with a particle size of 5-20 mm, to provide a larger microbial attachment area and enrich functional bacteria tolerant to long-chain fatty acids.

[0042] In this embodiment, the adjustable overflow weir 4 is one of the following: annular adjustable weir, sleeve-type adjustable weir, inclined guide-type adjustable weir, or porous flow-blocking adjustable weir.

[0043] like Figure 3 As shown, one specific embodiment of the adjustable overflow weir 4 includes an overflow weir body. The overflow weir body is provided with three sets of overflow hole groups (i.e., upper overflow hole group, middle overflow hole group, and lower overflow hole group) arranged at the top, middle, and bottom, as well as a sealing element 41 for maintaining the seal of the anaerobic system. The overflow holes include several horizontally arranged overflow holes 42. An electrically controlled gate 43 is provided inside the overflow hole 42. The overflow weir body is provided with a guide rail 44 that cooperates with the electrically controlled gate 43. The electrically controlled gate 43 is slidably installed in the guide rail 44. When the electrically controlled gate 43 is opened, it slides upward along the guide rail 44 to expose the overflow hole 42. When closed, it slides downward along the guide rail 44 to block the overflow hole 42.

[0044] In this embodiment, the adjustable overflow weir 4 is provided with three preset overflow heights. In the steady-state co-digestion mode, the adjustable overflow weir 4 is at the first overflow weir height. At this time, the electrically controlled gates 43 on the upper overflow hole group, the middle overflow hole group, and the lower overflow hole group are all open, so that the high oil mixture continuously enters the main digestion zone after completing the basic oil interception and degradation.

[0045] In peak shaving and slow release mode, the adjustable overflow weir 4 is raised to the height of the second overflow weir orifice. At this time, all the electrically controlled gates 43 on the lower overflow orifice group are closed to extend the buffer dwell time.

[0046] In the high oil impact protection mode, the adjustable overflow weir 4 is raised to the height of the third overflow weir orifice. At this time, the electrically controlled gates 43 on the lower overflow orifice group and the middle overflow orifice group are all closed, allowing the high oil material to undergo a longer period of floating, interception, and accelerated degradation within the high oil degradation buffer structure 2. The first overflow height is lower than the second overflow height, and the second overflow height is lower than the third overflow height. Electrically controlled gates are respectively installed on the first and second height overflow orifice groups, and the third height overflow orifice group is a normally open high-level overflow orifice group. The above three preset overflow heights are only one preferred embodiment. In other embodiments, two, four, or more preset overflow heights may also be set.

[0047] In this embodiment, the bottom slag-locking zone includes a conical shrinking structure and a slag-locking chamber 8 connected to the bottom of the conical shrinking structure. The upper and lower ends of the slag-locking chamber 8 are respectively provided with electrically controlled knife gate valves 7. The upper and lower electrically controlled knife gate valves 7 are provided with an interlocking control mechanism so that the two cannot be in the open state at the same time. The slag-locking chamber 8 is a sealed transition chamber and is provided with one or more of the following: a pressure balance port, a flushing port, a slag discharge observation port, a slag discharge pipe, or a slag discharge pump interface.

[0048] During slag discharge, first open the upper electrically controlled knife gate valve to allow heavy impurities to enter the slag-locking chamber 8, then close the upper electrically controlled knife gate valve to isolate the slag-locking chamber 8 from the anaerobic system, and then open the lower electrically controlled knife gate valve to discharge the heavy impurities. Through the above method, the step-by-step isolation and discharge of heavy impurities such as bone residue, sand, shell fragments, and small metal particles can be achieved under anaerobic closed conditions.

[0049] A method for shock-resistant modification of existing anaerobic digesters for high-oil co-digestion specifically includes the following steps: A. Obtain the feed amount and oil content of the high-oil organic waste, and obtain at least two operating parameters from the following: volatile fatty acid concentration, pH, alkalinity, gas production rate fluctuation, methane content change, and liquid level in the high-oil degradation buffer structure 2 within the anaerobic digester 1. B. Based on the parameters in step A, switch the system to one of the following modes: steady-state co-digestion mode, peak shaving and slow release mode, or high oil shock protection mode. When the feed load of high-oil organic waste is within the preset low load range, and the pH, volatile fatty acid concentration and gas production rate of the main digestion zone are all within a stable range, it is determined to be a steady-state co-digestion mode. When the feed load of high-oil organic waste increases, or when any of the following phenomena occur in the main digestion zone: increased concentration of volatile fatty acids, decreased pH, or fluctuation in gas production rate, it is determined to be peak-shaving and slow-release mode. When the feed load of high-oil organic waste exceeds the preset high load range, or when at least two of the following phenomena occur simultaneously in the main digestion zone: increased volatile fatty acid concentration, decreased pH, and decreased gas production rate, it is determined to be a high-oil shock protection mode. C. Part of the digested sludge discharged from the discharge pipe 11 is led out through the return inoculation branch and mixed with high-oil organic waste according to the return inoculation ratio corresponding to the system mode to form a high-oil mixture after inoculation and dilution. In the steady-state co-digestion mode, the volume ratio of partially digested sludge to high-oil organic waste is controlled at 1:1 to 2:1, the adjustable overflow weir 4 is at the first weir crest height, and the stirring paddle device 5 operates in a continuous low-intensity or intermittent low-intensity mode. In the peak-shaving and slow-release mode, the volume ratio of partially digested sludge to high-oil organic waste is controlled at 2:1 to 4:1. The adjustable overflow weir 4 is raised to the height of the second weir crest, and the stirring paddle device 5 performs a cycle of pulse stirring, low-speed maintenance, and weir-controlled release. In the high oil impact protection mode, the volume ratio of partially digested sludge to high oil organic waste is controlled at 4:1 to 5:1. The adjustable overflow weir 4 is raised to the height of the third weir crest, and the stirring paddle device 5 performs a periodic operation process of pulse mixing, static floating, packing interception, and slow release. Among them, the height of the third dam crest is higher than that of the second dam crest, and the height of the second dam crest is higher than that of the first dam crest. D. The high-oil mixture is fed into the bottom of the high-oil degradation buffer structure 2 through the high-oil organic waste feed pipe 10; E. The stirring device 5 is controlled to form a bottom-up circulating flow, so that the high oil mixture is buffered and dispersed in the high oil degradation buffer structure 2, and the oil droplets migrate to the biochar packing bed 3 along the floating path. F. The floating oil droplets are adsorbed, trapped and dispersed at the biochar packing bed 3, and biodegraded by the microorganisms attached to the biochar packing bed 3. G. Adjust the opening and closing of the overflow hole group at different heights on the adjustable overflow weir 4 according to the high oil impact risk level, so that the buffered material enters the main digestion zone at a release rate corresponding to the high oil impact risk level. H. Municipal sludge is fed into the main digestion zone of anaerobic digester 1 through municipal sludge inlet 9. The material in the main digestion zone continues to be anaerobically digested under the action of main digestion tank stirring device 6. The digested material is discharged through discharge pipe 11, and the biogas generated is discharged through exhaust pipe 12. I. Heavy impurities deposited at the bottom of the high-oil degradation buffer structure 2 are allowed to enter the slag-locking chamber 8, and intermittent isolation and discharge are achieved through the timed opening and closing of two electrically controlled knife gate valves 7.

[0050] The above description is not intended to limit the present invention in any way. Although the present invention has been disclosed through the above embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A shock-resistant modification device for high-oil co-digestion of existing anaerobic digesters, characterized in that, It includes an anaerobic digester (1) and a high-oil degradation buffer structure (2) that is vertically installed at the top of the inner cavity of the anaerobic digester (1); The high-oil degradation buffer structure (2) is divided into an upper oil interception and degradation zone, a middle circulation buffer zone, a lower inoculation feeding zone, and a bottom slag-locking zone from top to bottom. The upper oil interception and degradation zone is equipped with an adjustable overflow weir (4) and a biochar packing bed (3). The bottom slag-locking zone is equipped with an electrically controlled knife gate valve (7). The anaerobic digester (1) is provided with a municipal sludge inlet (9), a high-oil organic waste inlet pipe (10), an outlet pipe (11) and an exhaust pipe (12); the exhaust pipe (12) is connected to the upper oil interception and degradation zone, the high-oil organic waste inlet pipe (10) is connected to the lower inoculation inlet zone, the municipal sludge inlet (9) is connected to the upper part of the inner cavity of the anaerobic digester (1), and the outlet pipe (11) is connected to the bottom of the inner cavity of the anaerobic digester (1); The high-oil degradation buffer structure (2) is equipped with a stirring device (5), the upper end of which extends out of the top of the anaerobic digester (1), and the lower end is located in the middle circulation buffer zone.

2. The shock-resistant retrofit device for high-oil co-digestion of existing anaerobic digesters according to claim 1, characterized in that, The anaerobic digester (1) is equipped with a main digester stirring paddle (6).

3. The shock-resistant retrofit device for high-oil co-digestion of existing anaerobic digesters according to claim 1, characterized in that, The high-oil degradation buffer structure (2) is a vertical cylindrical structure, a vertical box-shaped structure, an upper cylindrical and lower conical structure, or an irregular structure adapted to the internal space of the anaerobic digester (1).

4. The shock-resistant retrofit device for high-oil co-digestion of existing anaerobic digesters according to claim 1, characterized in that, A reflux inoculation branch is provided between the discharge pipe (11) and the high-oil organic waste inlet pipe (10); the reflux inoculation branch includes a reflux pipe (17) and a mixer (15); the two ends of the reflux pipe (17) are respectively connected to the discharge pipe (11) and the mixer (15), one end of the high-oil organic waste inlet pipe (10) is connected to the mixer (15), and the mixer (15) is provided with an external high-oil organic waste inlet pipe (16).

5. The shock-resistant retrofit device for high-oil co-digestion of existing anaerobic digesters according to claim 1, characterized in that, The biochar packing bed (3) includes an oil interception buffer layer and a biodegradation promoting layer from top to bottom; the oil interception buffer layer uses larger particle size biochar packing material, with a particle size of 20 to 50 mm, to reduce the risk of clogging and to initially intercept and disperse large oil droplets or oil clumps; the biodegradation promoting layer uses smaller particle size biochar packing material, with a particle size of 5 to 20 mm, to provide a larger microbial attachment area and enrich functional bacteria that are tolerant to long-chain fatty acids.

6. The shock-resistant retrofit device for high-oil co-digestion of existing anaerobic digesters according to claim 1, characterized in that, The adjustable overflow weir (4) includes an overflow weir body, on which three sets of overflow holes are arranged at the top, middle and bottom. The overflow holes include several horizontally arranged overflow holes (42). An electrically controlled gate (43) is provided inside the overflow hole (42). A guide rail (44) that cooperates with the electrically controlled gate (43) is provided on the overflow weir body. The electrically controlled gate (43) is slidably installed in the guide rail (44). When the electrically controlled gate (43) is opened, it slides upward along the guide rail (44) to expose the overflow hole (42). When it is closed, it slides downward along the guide rail (44) to block the overflow hole (42).

7. The shock-resistant retrofit device for high-oil co-digestion of existing anaerobic digesters according to claim 1, characterized in that, The bottom slag-locking area includes a conical shrinking structure and a slag-locking cavity (8) connected to the bottom of the conical shrinking structure. Electrically controlled knife gate valves (7) are respectively installed at the upper and lower ends of the slag-locking cavity (8).

8. A method for shock-resistant modification of existing anaerobic digesters for high-oil co-digestion, characterized in that, Specifically, the following steps are included: A. Obtain the feed amount and oil content of high-oil organic waste, and obtain at least two operating parameters from the volatile fatty acid concentration, pH, alkalinity, gas production rate fluctuation, methane content change and high-oil degradation buffer structure (2) in the anaerobic digester (1); B. Based on the parameters in step A, switch the system to one of the following modes: steady-state co-digestion mode, peak shaving and slow release mode, or high oil shock protection mode. C. Part of the digested sludge discharged from the discharge pipe (11) is led out through the return inoculation branch and mixed with high-oil organic waste according to the return inoculation ratio corresponding to the system mode to form a high-oil mixture after inoculation dilution. D. The high-oil mixture is fed into the bottom of the high-oil degradation buffer structure (2) through the high-oil organic waste feed pipe (10); E. Control the stirring device (5) to form a bottom-up circulating flow, so that the high oil mixture is buffered and dispersed in the high oil degradation buffer structure (2), and the oil droplets migrate to the biochar packing bed (3) along the floating path; F. The floating oil droplets are adsorbed, trapped and dispersed on the biochar packing bed (3), and biodegradation occurs with the help of microorganisms attached to the biochar packing bed (3); G. Adjust the opening and closing of the overflow hole group at different heights on the adjustable overflow weir (4) according to the high oil impact risk level, so that the material after buffering treatment enters the main digestion zone at a release rate corresponding to the high oil impact risk level. H. The municipal sludge is fed into the main digestion zone of the anaerobic digester (1) through the municipal sludge inlet (9). The material in the main digestion zone continues to be anaerobically digested under the action of the stirring device (6) in the main digestion tank. The digested material is discharged through the discharge pipe (11), and the biogas generated is discharged through the exhaust pipe (12). I. Heavy impurities deposited at the bottom of the high-oil degradation buffer structure (2) are allowed to enter the slag-locking chamber (8) and are intermittently isolated and discharged through the timed opening and closing of two electrically controlled knife gate valves (7).

9. A method for shock-resistant modification of existing anaerobic digesters with high-oil co-digestion according to claim 8, characterized in that, In step B, when the feed load of high-oil organic waste is within a preset low load range, and the pH, volatile fatty acid concentration and gas production rate of the main digestion zone are all within a stable range, it is determined to be a steady-state co-digestion mode. When the feed load of high-oil organic waste increases, or when any of the following phenomena occur in the main digestion zone: increased concentration of volatile fatty acids, decreased pH, or fluctuation in gas production rate, it is determined to be peak-shaving and slow-release mode. When the feed load of high-oil organic waste exceeds the preset high load range, or when at least two of the following phenomena occur simultaneously in the main digestion zone: increased volatile fatty acid concentration, decreased pH, and decreased gas production rate, it is determined to be in high-oil shock protection mode.

10. A method for shock-resistant modification of existing anaerobic digesters with high-oil co-digestion according to claim 8, characterized in that, The ratio of partial digested sludge to high-oil organic waste recirculation inoculation is synergistically adjusted with the preset overflow height of the adjustable overflow weir (4); In step G, when the risk level of high oil shock increases, the reflux inoculation ratio is increased and the adjustable overflow weir (4) is switched to a higher preset overflow height to enhance the inoculation dilution effect and prolong the residence time of the high oil mixture; when the risk level of high oil shock decreases, the reflux inoculation ratio is decreased and the adjustable overflow weir (4) is switched to a lower preset overflow height to increase the release rate. The volume ratio of the partially digested sludge to the high-oil organic waste is 1:1 to 5:1; wherein, in the steady-state co-digestion mode, it is 1:1 to 2:1, in the peak-shaving and slow-release mode, it is 2:1 to 4:1, and in the high-oil shock protection mode, it is 4:1 to 5:1.

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