Anaerobic fermentation intelligent closed loop self-control and fault emergency compensation system

Abstract

The present application relates to the field of anaerobic fermentation process control, and discloses an intelligent closed-loop self-control and fault emergency compensation system for anaerobic fermentation, which comprises a kitchen pretreatment oil extraction control module, an anaerobic fermentation intelligent control module, a biogas system interaction module, an industrial communication transmission module, a data acquisition and storage module, a multi-stage early warning regulation module and a fault emergency compensation module, the industrial communication transmission module serves as a data hub, two-stage early warning mechanisms are provided, and when a device fails, a standby unit is automatically switched and process parameters are synchronously adjusted, so that problems such as acidification and load fluctuation can be intervened in advance.The present application solves the defects of manual regulation lag, large working condition fluctuation and biochemical collapse caused by sudden failure, improves the running stability of the anaerobic fermentation system, and reduces operation and maintenance costs.

Description

Technical Field

[0001] This invention relates to the field of anaerobic fermentation process control, specifically to an intelligent closed-loop automatic control and fault emergency compensation system for anaerobic fermentation. Background Technology

[0002] With the full implementation of waste sorting and the continuous advancement of policies for the resource utilization of organic solid waste, anaerobic fermentation has become the mainstream core technology for the resource utilization of organic solid waste such as kitchen waste. Kitchen waste generally adopts wet anaerobic fermentation technology, which mainly relies on microorganisms to decompose and digest organic matter to produce biogas and solidify the fermentation residue to achieve waste reduction and energy conversion. The complete process includes four major units: kitchen waste pretreatment system, wet anaerobic fermentation system, biogas collection and utilization system, and biogas slurry treatment system. The materials, loads, and gas production conditions of each section are deeply coupled. Fluctuations in parameters of any link will impact the anaerobic fermentation biochemical system, resulting in a significant decrease in the processing capacity of the entire production line. The anaerobic fermentation process is essentially a highly sensitive multi-microbial symbiotic biochemical reaction system. Its steady-state operation is highly dependent on the precise coordination of biochemical indicators (VFA / TAC, pH, OLR, NH3-N, etc.) in the tank, while physicochemical parameters such as temperature and material solids content will directly lead to changes in the biochemical indicators in the tank. Among the microbial communities in anaerobic systems, methanogens have the most stringent environmental requirements and the narrowest tolerance threshold, acting as a "rate-limiting link" for system stability. Significant fluctuations in temperature and other factors immediately inhibit the metabolic activity of methanogens, obstructing their methanogenesis pathways. This blockage directly leads to the rapid accumulation of intermediate metabolites—volatile fatty acids (VFAs)—resulting in a large-scale depletion of the system's buffer system (alkalinity), causing a continuous drop in pH and creating a vicious cycle of "acid accumulation → further inhibition of methanogenesis activity → accelerated acid accumulation." Ultimately, this manifests as a sharp drop in gas production, and in severe cases, can lead to complete system acidification and collapse, requiring re-inoculation and cleaning, directly impacting production for months and causing substantial economic losses and environmental impact.

[0003] Currently, most anaerobic fermentation systems in China are equipped with basic online monitoring equipment, which can collect basic operating data such as temperature, pH, and biogas flow rate. This enables the visualization of basic parameters, reducing the pressure of manual inspection to a certain extent, and represents a fundamental direction for the digital upgrade of the organic solid waste treatment industry.

[0004] However, existing anaerobic fermentation monitoring and control schemes still have the following problems: First, key balance indicators such as VFA / TAC, ammonia nitrogen, and total N rely solely on manual laboratory sampling and testing, which cannot capture early signs of acidification and ammonia inhibition in real time. Control measures are severely delayed and the optimal intervention window is easily missed. Second, the temperature, feed, and heat exchange systems only have data display functions and lack a mechanism for linking and regulating abnormal parameters. All control decisions depend on the operator's experience and judgment, and there is no real-time feedback optimization after manual adjustments, resulting in large parameter fluctuations and poor system shock resistance. Third, the anaerobic system lacks communication interconnection with the front-end pretreatment system and the back-end biogas system, leading to high concentrations of pretreatment effluent. The inability to synchronize changes in temperature and biogas storage load, with each unit operating independently, easily leads to drastic fluctuations in anaerobic feed load and a mismatch between biogas supply and demand. Fourth, when key equipment such as feed pumps, mixers, heat exchangers, and biogas blowers malfunction, only manual on-site handling is possible, without the ability to automatically activate backup equipment, synchronously compensate and adjust feed and temperature control parameters. The impact of malfunctions can quickly deteriorate the biochemical state inside the tank. Fifth, relying solely on simple over-threshold alarms, there is no way to automatically fine-tune or handle emergencies based on the magnitude of deviations in indicators. It is difficult to predict the risk of biochemical imbalance in advance, resulting in poor long-term system stability, large fluctuations in biogas production, and persistently high maintenance labor costs and downtime risks. Summary of the Invention

[0005] The present invention aims to provide an intelligent closed-loop automatic control and fault emergency compensation system for anaerobic fermentation, in order to solve the problems of lagging biochemical index detection, lack of cross-system linkage, lack of automatic closed-loop control and hierarchical early warning, lack of intelligent compensation for equipment failure, high dependence on manual operation throughout the process leading to easy imbalance of operating conditions, unstable gas production, and high operation and maintenance costs in existing anaerobic fermentation processes.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: an intelligent closed-loop self-control and fault emergency compensation system for anaerobic fermentation, comprising a kitchen waste pretreatment oil extraction control module, an anaerobic fermentation intelligent control module, a biogas system interaction module, an industrial communication transmission module, a data acquisition and storage module, a multi-level early warning and control module, and a fault emergency compensation module; the kitchen waste pretreatment oil extraction control module is the main body for front-end slurry conditioning and separation control, integrating material buffering and impurity removal, steam constant temperature conditioning, three-phase centrifugal oil extraction, water-slag phase ratio reflux, and homogenization tank feeding linkage full-process automatic control functions, realizing stable and controllable slurry temperature, concentration, and conveying flow rate; the anaerobic fermentation intelligent control module integrates online biochemical detection, in-tank heat exchange temperature control, biogas slurry reflux, and acid-base adjustment functions, and collects multiple biochemical indicators of the wet anaerobic tank in real time. It achieves automated closed-loop regulation of feeding and heat exchange conditions; the industrial communication transmission module adopts fiber optic networking and is equipped with dual communication protocols to realize data exchange and coordinated control among the three modules: the kitchen waste pretreatment oil extraction control module, the anaerobic fermentation intelligent control module, and the biogas system interaction module; the data acquisition and storage module uniformly collects equipment operation data and biochemical process data of the entire process, and is equipped with a visual monitoring interface to realize long-term storage of historical operation data; the multi-level early warning and control module is configured with yellow and red two-level early warning thresholds, and can automatically perform graded fine-tuning or emergency handling operations according to the degree of deviation of indicators; the fault emergency compensation module collects the operating status of key equipment in real time, automatically puts into operation the backup equipment after identifying equipment failure, and simultaneously adjusts the process parameters to compensate for the fluctuation of operating conditions, reducing the impact of failure on the anaerobic biochemical system.

[0007] The beneficial effects of this solution are as follows: Relying on the coordinated operation of the food waste pretreatment oil extraction control module, the anaerobic fermentation intelligent control module, the biogas system interaction module, the industrial communication transmission module, the data acquisition and storage module, the multi-level early warning and control module, and the fault emergency compensation module, it can continuously collect multiple biochemical data such as VFA / TAC and ammonia nitrogen online, predict acidification and ammonia inhibition risks in real time, and eliminate the control lag problem caused by manual sampling; the entire system forms a closed-loop self-control loop of data acquisition, calculation and adjustment, and result feedback, which can stably maintain the tank temperature and feeding conditions without continuous manual intervention, significantly improving the anaerobic system's resistance to load shocks; industrial communication transmission... The feed module breaks down data barriers between different work sections, enabling coordinated operation of slurry preparation, anaerobic digestion, and biogas storage, stabilizing feed concentration and smoothing out biogas production fluctuations. The fault emergency compensation module can automatically activate the backup unit after equipment failure, while simultaneously adjusting process parameters to buffer process disturbances caused by equipment shutdown and prevent severe impacts on the anaerobic microbial system. Multi-level early warning can perform fine-tuning or emergency handling according to the degree of deviation of indicators, enabling early intervention in anomalies, significantly reducing the probability of production accidents. The fully automated operation of the entire process also reduces the number of on-site personnel, lowers operation and maintenance costs, and ensures the long-term continuous and stable operation of the anaerobic fermentation unit.

[0008] Preferably, the further improvement is that the pre-treatment oil extraction control module for kitchen waste includes a buffer tank, a slag remover, a feeding heating buffer tank, a steam temperature control unit, a centrifuge feed pump flow closed-loop unit, a three-phase centrifuge, an oil storage tank, a water phase reflux proportioning unit, a slag phase homogenization conveying unit, and a homogenization tank level linkage unit; the material is conveyed sequentially along the buffer tank, the slag remover, the feeding heating buffer tank, and the three-phase centrifuge, and the three-phase centrifuge separates oil, water, and slag into three phases, which correspond to the oil storage tank, the water phase reflux proportioning unit, and the slag phase homogenization conveying unit, respectively. The material output from the slag phase homogenization conveying unit is sent into the homogenization tank via the homogenization tank level linkage unit.

[0009] The beneficial effects are as follows: it limits the equipment composition and material conveying path of the pre-treatment oil extraction control module for kitchen waste, and builds an automated production line for buffering and impurity removal, constant temperature conditioning, three-phase centrifugal separation, and slurry proportioning and conveying. It can continuously deliver uniformly composed feed slurry to the anaerobic section, reduce feed load fluctuations from the source, and create stable feed conditions for the back-end anaerobic closed-loop control.

[0010] Preferably, the feed heating buffer tank includes a first buffer tank and a second buffer tank, with a liquid level control range of 0.5 to 1.5 m and the parameters can be customized; the steam temperature control unit collects the slurry temperature and adjusts the steam valve to stably control the slurry temperature at 70 to 80°C.

[0011] The beneficial effects are: the dual-group feeding heating buffer tank and steam temperature control strategy allow for flexible configuration of tank level parameters, and the slurry temperature is stably maintained at 70-80℃, which not only ensures the efficiency of three-phase centrifugal oil extraction, but also ensures the stable quality of the aqueous and slag phase outputs, further stabilizing the downstream feed indicators.

[0012] Preferably, the aqueous phase reflux proportioning unit is equipped with an aqueous phase reflux regulating tank. The reflux water pump is started and stopped proportionally according to the centrifuge feed flow rates corresponding to the first slag phase conditioning tank and the second slag phase conditioning tank to stabilize the feed TS. The aqueous phase reflux regulating tank has an adjustable volume of 500-1000m³ for slurry reflux to the front-end pulping process.

[0013] The beneficial effects are as follows: the linkage control logic of limiting the aqueous phase reflux ratio can automatically adjust the start and stop of the reflux water pump according to the centrifuge feed flow rate, stabilize the TS value of the homogenizing tank feed, and reserve an adjustable volume in the reflux tank to realize the slurry reflux conditioning, effectively narrowing the fluctuation range of feed concentration and avoiding the impact of front-end material fluctuations on the anaerobic fermentation system.

[0014] Preferably, the slag phase homogenization conveying unit includes a first slag phase conditioning tank and a second slag phase conditioning tank. The conditioning tank is equipped with a cooling heat exchange device to regulate the discharge temperature. The homogenization tank liquid level linkage unit adjusts the conveying capacity of the booster pump according to the homogenization tank liquid level. When the homogenization tank liquid level is lower than 6.5m, the pump is automatically started. When the liquid level exceeds the set upper limit, the manual control mode is switched.

[0015] The beneficial effects are as follows: by configuring a dual-slag phase conditioning tank and a cooling heat exchange device, the temperature of the slurry entering the tank can be precisely controlled. The start and stop of the feed pump can be automatically controlled by the liquid level interlock of the homogenization tank, so as to achieve uniform and continuous feeding and eliminate the disturbance of the anaerobic bacterial community's living environment by intermittent large-flow feeding.

[0016] Preferably, the centrifuge feed pump flow closed-loop unit collects flow, current, and vibration parameters for frequency conversion and flow stabilization, and sets temperature and low liquid level safety interlocks; the three-phase centrifuge collects speed, differential speed, and vibration parameters, and automatically reduces the feed flow when the oil content in the liquid or slag phase exceeds the standard; the cooling heat exchange device controls the temperature at 50-58℃, and triggers an audible and visual alarm if the temperature exceeds the standard for 30 minutes.

[0017] The beneficial effects are: the addition of protection mechanisms such as variable frequency flow stabilization of the feed pump, safety interlock between temperature and low liquid level, automatic load reduction of the centrifuge when the oil content exceeds the standard, and audible and visual alarms for the cooling system after timeout. These mechanisms not only ensure the safe operation of the equipment, but also prevent problems such as oily slurry and abnormal temperature from being passed on, and prevent oil from inhibiting the activity of anaerobic microorganisms.

[0018] Preferably, the intelligent control module for anaerobic fermentation includes a wet anaerobic tank, a homogenizing tank feeding linkage unit, a heat exchange temperature control unit, an online biochemical detection unit, an alkali addition adjustment unit, and a biogas slurry reflux adjustment unit. The online biochemical detection unit collects VFA / TAC, ammonia nitrogen, and total N every hour. The reference temperature inside the tank is 56±1℃. The feed rate and biogas slurry reflux are adjusted according to the VFA / TAC range. Alkali is automatically added when the indicators deteriorate.

[0019] The beneficial effects are as follows: By limiting the hardware structure of the intelligent control module for anaerobic fermentation and the multi-index linkage control strategy, it can not only automatically adjust the heat exchange load according to the temperature inside the tank, but also combine multiple indicators such as VFA / TAC and ammonia nitrogen to control the feed rate, biogas slurry return flow and reagent dosage in a graded manner, thereby suppressing acidification, ammonia nitrogen exceeding the standard and load exceeding the limit in a graded manner, and further improving the operational stability of the anaerobic system.

[0020] Preferably, the industrial communication transmission module adopts a star Ethernet local network, with Modbus-TCP used locally and Profinet fiber optic communication used across modules; the data acquisition and storage module is equipped with a dual-machine hot standby database, with data storage for no less than one year, and is equipped with a visual large screen to realize parameter viewing and automatic report generation; the biogas system interaction module monitors the storage tank volume, and automatically reduces the anaerobic gas production rate when the volume is full.

[0021] The beneficial effects are: limiting the network communication architecture, database storage configuration and cross-section linkage logic, relying on fiber optic dual-protocol communication to ensure stable and reliable data transmission, large-capacity database to retain operating data for a long time, and relying on the biogas storage tank liquid level to automatically adjust the anaerobic gas production rate to achieve dynamic balance of the entire process.

[0022] Preferably, the multi-level early warning and control module is set with yellow and red warning levels; the yellow warning automatically fine-tunes the process parameters and pushes operation and maintenance prompts; the red warning executes emergency operations such as reducing feed volume, increasing biogas slurry reflux, and switching tanks to release pressure, and simultaneously provides audible and visual alarms.

[0023] The beneficial effects are: a two-level quantitative early warning mechanism is set up, relying on multiple sets of continuous data to determine anomalies to avoid false alarms, and graded fine-tuning of processes and emergency pressure relief and reduction operations are carried out to eliminate potential accidents in the bud.

[0024] Preferably, the fault emergency compensation module identifies pump, agitator, heat exchanger, and fan faults within 1 second and switches to backup equipment, while simultaneously adjusting process parameters and intensifying biochemical detection and pre-control. The system adopts a five-layer distributed architecture, with built-in PID and gas production prediction models, and the control response is less than 5 minutes, forming a complete biochemical closed-loop automatic control system.

[0025] The beneficial effects are: automatic fault switching, process pre-control mechanism and overall system architecture, fast equipment fault response speed, controllable control closed-loop response time, and the supporting fault review and emergency drill mechanism, which further enhances the system's ability to resist sudden risks. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the process flow for the oil extraction section of the pre-treatment of kitchen waste according to the present invention; Figure 2 This is a block diagram of the overall structure of the intelligent automatic control system for anaerobic fermentation of the present invention. Detailed Implementation

[0027] The following detailed description illustrates the specific implementation method: Example like Figure 1-2As shown, an intelligent closed-loop automatic control and fault emergency compensation system for anaerobic fermentation includes a kitchen waste pretreatment oil extraction control module, an anaerobic fermentation intelligent control module, a biogas system interaction module, an industrial communication transmission module, a data acquisition and storage module, a multi-level early warning and control module, and a fault emergency compensation module. In the kitchen waste pretreatment oil extraction control module, the material flows sequentially through a buffer tank and a slag remover before being fed into a feeding heating buffer tank. The feeding heating buffer tank includes a first buffer tank and a second buffer tank, with a liquid level control range of 0.5–1.5 m. Control parameters can be customized and modified on a touchscreen. The steam temperature... The control and regulation unit collects the slurry temperature in the tank in real time and automatically adjusts the opening of the steam regulating valve to maintain the slurry temperature at a constant 70-80℃. The slurry is delivered to the three-phase centrifuge via the centrifuge feed pump flow closed-loop unit. The flow closed-loop unit collects the feed flow rate, motor current, and vibration values ​​in real time, and relies on the frequency converter to stabilize the feed flow rate. The system is equipped with dual safety interlocks: if the slurry temperature is below 60℃ for 5 consecutive minutes, the feed pump is automatically shut off; if the buffer tank reaches a low level, the steam valve is interlocked and shut off. The three-phase centrifuge collects the speed, differential speed, torque, and vibration operating parameters in real time, and if any of these parameters are not collected, the system will shut off the feed pump. If the oil content in the liquid and slag phases exceeds the standard, the front-end feed load is immediately and automatically reduced. Three-phase separation produces three material streams: the oil phase enters the grease storage tank, the aqueous phase is transported to the aqueous phase reflux conditioning tank, and the slag phase is sent to the slag phase homogenization conveying unit. The aqueous phase reflux proportioning unit reads the centrifuge feed flow rates corresponding to the first and second slag phase conditioning tanks and automatically starts and stops the reflux water pumps according to the set ratio to stabilize the feed TS to the downstream homogenization tank. The aqueous phase reflux conditioning tank has a reserved volume of 500-1000 m³, and the slurry reflux process supports free switching between manual and automatic modes. Slag phase homogenization... The conveying unit is equipped with two slag phase conditioning tanks, each with a cooling heat exchange device. The heat exchange device has two-stage control. When the slurry temperature is in the range of 50-58℃, it maintains normal cooling. If the slurry continues to overheat, the cooling water flow rate is increased first. If the overheating cannot be relieved, the standby cooling unit is automatically put into operation. If the overheating condition lasts for 30 minutes, the system triggers an on-site audible and visual alarm. The homogenization tank level linkage unit monitors the homogenization tank level in real time. When the level is below 6.5m, the slurry lift pump is automatically started. When the level reaches the upper limit, it automatically switches to manual operation mode. The upper limit value of the level can be customized on-site. The entire temperature control, reflux ratio, and pump interlocking process requires no manual intervention. After the sensors collect data, the PLC performs real-time calculations and outputs adjustment signals to the steam valve, variable frequency pump, and cooling unit in milliseconds to automatically execute the adjustment actions. On-site personnel only need to view the real-time trend curve on the touch screen daily. If the moisture content and oil content of the incoming kitchen materials change significantly, they can directly modify the temperature and reflux ratio thresholds in the parameter setting interface. After clicking save, the PLC will update the control program in real time. The system automatically records all parameter modification records and generates an operation log for archiving, which facilitates traceability of operating conditions.

[0028] The anaerobic fermentation intelligent control module feeds the effluent from the homogenizer into the wet anaerobic digester. The system includes a homogenizer feeding linkage unit, a heat exchange temperature control unit, an online biochemical detection unit, an alkali addition adjustment unit, and a biogas slurry reflux adjustment unit. The online biochemical detection unit is installed at the anaerobic digester outlet, collecting VFA / TAC, ammonia nitrogen, and total nitrogen data hourly, at least once per hour. It also simultaneously collects data on digester temperature, pH, and instantaneous biogas production. The normal operating baseline temperature of the anaerobic digester is controlled at 56±1℃. If the temperature is slightly lower, the steam heating valve is gradually opened. Under extreme low-temperature conditions, the feed load is reduced synchronously. If the digester temperature exceeds the standard, the water cooling device is activated first, and the high-temperature linkage with the front-end slurry cooling tower reduces the feed rate. Temperature: If the temperature exceeds the limit for an extended period, gradually reduce the feed rate according to the gradient. When the VFA / TAC ratio is between 0.2 and 0.4, automatically reduce the total feed amount and increase the biogas slurry return flow for dilution. When VFA / TAC > 0.4, significantly reduce the feed rate or even temporarily stop the feed. When the indicators continue to deteriorate and the acidification trend cannot be contained, automatically activate the alkali addition adjustment unit to add sodium bicarbonate or lime water to increase the alkalinity of the system. Maintain the total sulfide (TS) in the tank within a reasonable range of 2% to 4%. If the TS exceeds the limit for an extended period, link with the front-end pretreatment section to strengthen sand removal. If the excess cannot be eliminated, reduce the feed rate and shut down. When the ammonia nitrogen value approaches the warning threshold, coordinate with the front-end control system to reduce the proportion of high-nitrogen kitchen waste materials in the feed to avoid ammonia inhibition problems. The system employs a multi-input single-output coupled PID calculation logic, assigning weighted values ​​to four indicators: tank temperature, VFA / TAC, ammonia nitrogen, and TS. Independent adjustment increments are calculated based on the deviation of each indicator from its threshold, and then these increments are summed to obtain the final output for feed, heat exchange, and alkali addition. Slight deviations in a single indicator result in only minor adjustments, while simultaneous exceedances of multiple indicators amplify the adjustment weights, preventing unbalanced operation caused by controlling a single parameter.

[0029] Cross-section interaction and communication storage: The industrial communication transmission module uses a star topology industrial Ethernet to build a local area network, and field devices communicate using the Modbus-TCP protocol; the food waste pretreatment section, anaerobic section, and biogas section use fiber optic Profinet protocol for bidirectional data transmission, which has strong anti-electromagnetic interference capabilities; the data acquisition and storage module deploys a dual-machine hot standby database server, configured with Redis cache to store nearly one hour of real-time data, with a total hard disk storage capacity of no less than 2TB, and historical operation data storage duration of no less than one year; the system is equipped with a dedicated biochemical data processing server and gas production optimization computing node, with hardware configuration of an 8-core processor and 32G of RAM; the central control is equipped with a visualization screen to display the operating parameters of all sections with trend curves and dashboards, automatically generating daily and monthly production reports, and supporting historical data query and operation condition review; the biogas system interaction module reads the liquid level data of the gas storage tank in real time, and when the biogas storage reaches the upper limit, it automatically lowers the heat exchange temperature of the anaerobic tank to reduce the organic matter degradation rate, reduce biogas production, and prevent the gas storage system from overpressure. Simultaneously, a two-way linkage mechanism is established: when the pretreatment feed volume increases significantly, the stirring speed and heating temperature of the anaerobic digester are increased synchronously to ensure matching of digestion load. The system has a built-in load matching conversion formula, which calculates the organic load increment of the anaerobic digester based on the real-time feed TS and feed flow rate of the homogenizing tank at the front end. The stirring frequency, heat exchange steam opening, and biogas slurry recirculation ratio of the anaerobic digester are adjusted linearly and synchronously according to the load increment, achieving precise quantitative matching between feed load and digestion conditions, rather than coarse linkage. The system is equipped with automatic sensor cleaning control logic, which automatically starts the online detector and pipeline sensor clean water flushing program every 24 hours, with a flushing time of 5 minutes; and automatically retrieves standard calibration solution data every 7 days to complete the instrument zero-point calibration, reducing manual periodic disassembly and calibration operations and ensuring the long-term accuracy of biochemical data acquisition.

[0030] The multi-level early warning and control module divides the system into yellow and red warning thresholds. All warnings have added judgment conditions: an alarm is only triggered when three consecutive sets of monitoring data exceed the threshold, avoiding false alarms caused by single-point data fluctuations. If necessary, it prompts maintenance personnel to manually retest on-site. Yellow warning: slight temperature deviation, VFA / TAC approaching 0.2, and slight decrease in gas production. The system automatically fine-tunes the feed flow rate, steam pressure, and circulating water volume, and pushes a text notification to the mobile terminal. Red warning: temperature significantly deviating from the set value, VFA / TAC exceeding 0.4, and a significant decrease in gas production. The system automatically performs emergency operations such as reducing feed, increasing biogas slurry reflux, and tank depressurization, while simultaneously triggering on-site audible and visual alarms. All warning thresholds are quantified: a temperature deviation of ±0.5℃ from the set value triggers a yellow warning, and a deviation of ±1℃ triggers a red warning; a 10% decrease in gas production triggers a yellow warning, and a 30% decrease directly initiates red emergency response.

[0031] The fault emergency compensation module and overall architecture continuously monitor the operating current and status signals of the feed pump, agitator, heat exchanger, and biogas blower. The equipment fault identification response time is ≤1 second. Once a shutdown fault is detected, it automatically switches to the standby unit. Simultaneously, it reduces the feed rate, corrects heating parameters, and increases the frequency of biochemical index collection to proactively control and buffer the biochemical impact of equipment shutdown. The system has a complete operation and maintenance support mechanism: after a fault alarm is pushed, maintenance personnel are required to arrive on-site within 30 minutes; after fault handling, the system automatically retains the entire operation record, generates a fault analysis document within 24 hours, and outputs an optimized control plan within 72 hours. Spare sensors, pumps, and valves are readily available on-site, and quarterly emergency drills are conducted to simulate temperature-controlled shutdowns and equipment failures. The entire system adopts a layered distributed five-layer architecture: sensing layer, transmission layer, computing layer, control layer, and application layer. The system has a built-in PID closed-loop control unit and a gas production optimization prediction model, with a single control response time controlled within 5 minutes.

[0032] The specific implementation process is as follows: 1. Install temperature, liquid level, and flow sensors, online VFA / ammonia nitrogen biochemical analyzers, and current and vibration acquisition instruments at the pretreatment tank, centrifuge pipeline, anaerobic tank, and biogas pipeline points. Complete the hardware installation and wiring of regulating valves and frequency converters.

[0033] 2. Establish a star-shaped industrial Ethernet network. Field instruments are connected to the PLC via Modbus-TCP. Fiber optic cables are laid between the pretreatment section, anaerobic section, and biogas central control unit. Profinet communication links are configured to break down the data silos between the three sections.

[0034] 3. Set up a dual-machine hot standby database server and biochemical computing node, equipped with Redis real-time cache; build a monitoring screen on the WinCC configuration platform, and enter PID adjustment program, hierarchical early warning logic, equipment fault switching program, and all process thresholds and interlocking conditions.

[0035] 4. First, debug the oil extraction control module of the kitchen waste pretreatment separately, and adjust the steam temperature control, reflux ratio, and pump group interlock logic; then debug the temperature closed loop and biochemical index linkage feed control of the anaerobic fermentation section separately; finally, debug the cross-section data interaction and the linkage function between the gas storage tank and the anaerobic load.

[0036] 5. Gradually increase the load by adding kitchen slurry, verify the triggering conditions of yellow / red warning levels, test the automatic switching of standby units and the compensation effect of process parameters when pumps and heat exchangers fail, correct the control response time, and ensure that a single automatic control is completed within 5 minutes.

[0037] 6. Run continuously for 30 days without interruption, automatically retain operation logs, alarm records, and fault handling ledgers, improve the operation and maintenance procedures for 24-hour fault review and quarterly emergency drills, and finally complete the acceptance of the entire closed-loop automatic control system.

[0038] The above are merely embodiments of the present invention. Commonly known technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solution of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. An intelligent closed-loop automatic control and fault emergency compensation system for anaerobic fermentation, characterized in that: It includes a kitchen waste pretreatment oil extraction control module, an anaerobic fermentation intelligent control module, a biogas system interaction module, an industrial communication transmission module, a data acquisition and storage module, a multi-level early warning and control module, and a fault emergency compensation module; The pretreatment oil extraction control module for kitchen waste is the main body of front-end slurry conditioning and separation control. It integrates the functions of material buffering and impurity removal, steam constant temperature conditioning, three-phase centrifugal oil extraction, water-slag phase ratio reflux, and homogenization tank feeding linkage for the entire process of automatic control, so as to achieve stable and controllable slurry temperature, concentration, and conveying flow rate. The intelligent control module for anaerobic fermentation integrates online biochemical detection, in-tank heat exchange temperature control, biogas slurry reflux and acid-base adjustment functions. It collects multiple biochemical indicators of the wet anaerobic tank in real time and realizes automated closed-loop regulation of feeding and heat exchange conditions. The industrial communication transmission module adopts fiber optic networking and is equipped with dual communication protocols to realize data communication and coordinated control among the three modules: the kitchen waste pretreatment oil extraction control module, the anaerobic fermentation intelligent control module, and the biogas system interaction module. The data acquisition and storage module collects equipment operation data and biochemical process data from the entire work section, and is equipped with a visual monitoring interface to achieve long-term storage of historical operation data. The multi-level early warning and control module is equipped with yellow and red two-level early warning thresholds, and can automatically perform graded fine-tuning or emergency response operations according to the degree of deviation of the indicators. The fault emergency compensation module collects the operating status of key equipment in real time, automatically puts the backup equipment into operation after identifying equipment failure, and simultaneously adjusts process parameters to compensate for fluctuations in operating conditions, thereby reducing the impact of failures on the anaerobic biochemical system.

2. The anaerobic fermentation intelligent closed-loop automatic control and fault emergency compensation system according to claim 1, characterized in that, The pre-treatment oil extraction control module for kitchen waste includes a buffer tank, a slag remover, a feed heating buffer pool, a steam temperature control unit, a centrifuge feed pump flow closed-loop unit, a three-phase centrifuge, an oil storage tank, a water phase reflux proportioning unit, a slag phase homogenization conveying unit, and a homogenization pool level linkage unit. The material is conveyed sequentially along the buffer tank, slag remover, feed heating buffer tank, and three-phase centrifuge. The three-phase centrifuge separates oil, water, and slag into three phases, which correspond to the oil temporary storage tank, water phase reflux proportioning unit, and slag phase homogenization conveying unit, respectively. The material output from the slag phase homogenization conveying unit is sent into the homogenization tank via the homogenization tank level linkage unit.

3. The anaerobic fermentation intelligent closed-loop automatic control and fault emergency compensation system according to claim 2, characterized in that, The feed heating buffer tank includes a first buffer tank and a second buffer tank. The liquid level control range is 0.5 to 1.5 m and the parameters can be customized. The steam temperature control unit collects the slurry temperature and adjusts the steam valve to stably control the slurry temperature at 70 to 80°C.

4. The anaerobic fermentation intelligent closed-loop automatic control and fault emergency compensation system according to claim 2, characterized in that, The aqueous phase reflux proportioning unit is equipped with an aqueous phase reflux regulating tank. The reflux water pump is started and stopped proportionally according to the centrifuge feed flow rates corresponding to the first slag phase regulating tank and the second slag phase regulating tank to stabilize the feed TS. The aqueous phase reflux regulating tank has a reserved adjustable volume of 500-1000m³ for slurry reflux to the front-end pulping process.

5. The anaerobic fermentation intelligent closed-loop automatic control and fault emergency compensation system according to claim 2, characterized in that, The slag phase homogenization conveying unit includes a first slag phase conditioning tank and a second slag phase conditioning tank. The conditioning tank is equipped with a cooling heat exchange device to regulate the discharge temperature. The homogenization tank liquid level linkage unit adjusts the conveying capacity of the booster pump according to the homogenization tank liquid level. When the homogenization tank liquid level is lower than 6.5m, the pump is automatically started. When the liquid level exceeds the set upper limit, the manual control mode is switched.

6. The anaerobic fermentation intelligent closed-loop automatic control and fault emergency compensation system according to claim 2, characterized in that, The centrifuge feed pump flow closed-loop unit collects flow, current, and vibration parameters for frequency conversion and flow stabilization, and sets temperature and low liquid level safety interlocks; the three-phase centrifuge collects speed, differential speed, and vibration parameters, and automatically reduces the feed flow when the oil content in the liquid or slag phase exceeds the standard; the cooling heat exchange device controls the temperature at 50-58℃, and triggers an audible and visual alarm if the temperature exceeds the standard for 30 minutes.

7. The anaerobic fermentation intelligent closed-loop automatic control and fault emergency compensation system according to claim 1, characterized in that, The intelligent control module for anaerobic fermentation includes a wet anaerobic tank, a homogenizing tank feeding linkage unit, a heat exchange temperature control unit, an online biochemical detection unit, an alkali addition adjustment unit, and a biogas slurry reflux adjustment unit; The online biochemical detection unit collects VFA / TAC, ammonia nitrogen, total N, and TS every hour. The reference temperature inside the tank is 56±1℃. The feed rate and biogas slurry reflux are adjusted according to the VFA / TAC range. Alkali is automatically added when the indicators deteriorate.

8. The anaerobic fermentation intelligent closed-loop automatic control and fault emergency compensation system according to claim 1, characterized in that, The industrial communication transmission module adopts a star Ethernet local network, with Modbus-TCP used locally and Profinet fiber optic communication used across modules; the data acquisition and storage module is equipped with a dual-machine hot standby database, with data storage for no less than one year, and is equipped with a visual large screen to realize parameter viewing and automatic report generation. The biogas system's interactive module monitors the storage tank's capacity, and automatically reduces the anaerobic gas production rate when the capacity is full.

9. The anaerobic fermentation intelligent closed-loop automatic control and fault emergency compensation system according to claim 1, characterized in that, The multi-level early warning and control module is set with yellow and red warning levels. The yellow warning automatically adjusts the process parameters and pushes operation and maintenance prompts. The red warning executes emergency operations such as reducing feed volume, increasing biogas slurry reflux, and switching tanks to release pressure, and simultaneously provides audible and visual alarms.

10. The anaerobic fermentation intelligent closed-loop automatic control and fault emergency compensation system according to claim 1, characterized in that, The fault emergency compensation module identifies pump, agitator, heat exchanger, and fan faults within 1 second and switches to backup equipment, while simultaneously adjusting process parameters and intensifying biochemical detection and pre-control. The system adopts a five-layer distributed architecture, with built-in PID and gas production prediction models, and the control response is less than 5 minutes, forming a complete biochemical closed-loop automatic control system.

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