Heavy metal contaminated sludge treatment device based on environmental protection technology

Abstract

This invention relates to the field of sludge treatment technology and discloses a heavy metal contaminated sludge treatment device based on environmental protection technology. The device includes: a solid-liquid separation and variable load speed-regulating dewatering control module that generates rotation speed commands based on the initial moisture content of the incoming sludge and determines stage switching based on liquid level increments, outputting a moisture content estimate; a multi-temperature zone thermo-mass coupling drying and steam condensation control module that receives temperature setpoints and performs zoned closed-loop tracking, determining the drying endpoint based on thermal efficiency; a heavy metal targeted purification and self-regulating regeneration control module that calculates the decay rate coefficient based on effluent concentration and triggers backflushing regeneration; and a feedforward collaborative control module based on load prediction that collects status data from each module, calculates the purification load index, and issues temperature, moisture content, and treatment capacity adjustment commands to each module accordingly. This invention achieves data integration and closed-loop collaborative control throughout the entire dewatering, drying, and purification process, improving system operating efficiency and energy saving.

Description

Technical Field

[0001] This invention relates to the field of sludge treatment technology, specifically to a heavy metal contaminated sludge treatment device based on environmental protection technology. Background Technology

[0002] With the acceleration of industrialization and urbanization, the production of heavy metal-contaminated sludge has been increasing year by year. How to reduce its volume, render it harmless, and make it a resource-efficient treatment has become an important issue in the field of environmental protection. Heavy metal-contaminated sludge contains a large amount of water and toxic heavy metals such as lead, cadmium, and chromium. If it is discharged directly without proper treatment, it will cause serious pollution to soil and water bodies.

[0003] Currently, common heavy metal contaminated sludge treatment processes typically include three core stages: mechanical dewatering, thermal drying, and wastewater purification. In the mechanical dewatering stage, centrifuges or filter presses are often used for solid-liquid separation. In the thermal drying stage, the dewatered sludge is further dried using electric or steam heating to reduce its moisture content. In the wastewater purification stage, adsorption packing or chemical precipitation methods are used to remove heavy metal ions from the wastewater.

[0004] However, existing equipment still has some problems in use, such as: the control systems of each processing stage are independent of each other and lack a global coordination mechanism. Dewatering control only focuses on centrifugal speed, drying control only focuses on temperature setting, and purification control only focuses on effluent concentration. There is no data interaction or linkage adjustment between them, resulting in low overall system efficiency and high energy consumption. The stage switching of the dewatering process relies on manual experience or fixed timing, and cannot be adaptively adjusted according to the real-time changes in the moisture content of the incoming sludge, resulting in frequent occurrences of insufficient or excessive dewatering, affecting the load stability of subsequent drying stages. The determination of the drying endpoint is mostly based on fixed duration control, without considering the real-time correlation between changes in material moisture content and thermal efficiency, which easily leads to insufficient drying resulting in substandard output or excessive drying resulting in energy waste. The purification stage lacks online monitoring and automatic regeneration control of the adsorption state of the packing material. When the packing material tends to penetrate or fail, backwash regeneration cannot be triggered in time, increasing the risk of excessive heavy metal concentration in the effluent. Summary of the Invention

[0005] This invention provides the following technical solution: a heavy metal contaminated sludge treatment device based on environmental protection technology, comprising a support cabinet with a sealed door hinged to its front side, and control components on the side of the support cabinet; a centrifugal mechanism fixedly installed inside the support cabinet and positioned opposite the sealed door; a drying mechanism fixedly installed inside the support cabinet and located below the centrifugal mechanism; a conveying pipe, one end of which connects to the sealed door and the other end of which connects to the drying mechanism; a discharge mechanism installed inside the support cabinet and positioned to the side of the drying mechanism; a water storage tank installed inside the support cabinet and located directly below the centrifugal mechanism; a purification mechanism fixedly installed on the rear side of the support cabinet and connected to the bottom of the water storage tank; and a detector fixedly installed on the side of the purification mechanism.

[0006] In a preferred embodiment, the control element (2) includes:

[0007] The solid-liquid separation and variable load speed regulation dewatering control module is used to generate centrifuge speed commands based on the initial moisture content of the incoming sludge, and to determine the switching of the dewatering stage based on the change in liquid level increment to execute variable load control. After the dewatering is completed, it outputs the estimated moisture content of the sludge.

[0008] The multi-temperature zone thermo-mass coupling drying and steam condensation control module is used to receive the drying temperature setpoint and perform zoned temperature closed-loop tracking accordingly, and calculate the thermal efficiency factor based on the material mass change to determine the drying endpoint.

[0009] The heavy metal targeted purification and self-regulating regeneration control module is used to calculate the concentration decay rate coefficient based on the heavy metal concentration in the effluent, trigger hydraulic backwash regeneration when the coefficient is lower than the threshold, and output the purified effluent concentration and influent flow rate data.

[0010] The feedforward collaborative control module based on load prediction is used to receive the estimated sludge moisture content, drying chamber gas phase temperature, purified influent concentration, purified effluent concentration and influent flow rate data, calculate the purification load index, and send the drying temperature setpoint to the multi-temperature zone thermo-mass coupling drying and steam condensation control module and the target moisture content setpoint to the solid-liquid separation and variable load speed regulation dewatering control module according to the range of the purification load index.

[0011] The present invention has the following beneficial effects:

[0012] 1. This invention adaptively generates centrifuge speed commands based on the initial moisture content of the incoming mud, and automatically determines the switching timing between the two stages of free water removal and interstitial water compaction based on the change in liquid level increment, and executes step-by-step speed control, which effectively solves the problems of relying on manual experience for switching of dewatering stages, insufficient dewatering or over-dewatering in the prior art.

[0013] 2. This invention divides the drying chamber into a radiation preheating zone, a constant-speed drying zone, and a falling-speed final drying zone for zoned temperature closed-loop tracking control, and calculates the thermal efficiency factor based on changes in material mass to determine the drying endpoint. This solves the problem of insufficient drying or energy waste caused by fixed-duration control in the prior art, and effectively reduces drying energy consumption while ensuring that the output moisture content meets the standard.

[0014] 3. This invention determines the packing penetration trend by real-time monitoring of the heavy metal concentration in the effluent and calculating the concentration decay rate coefficient. When the adsorption efficiency decreases, it automatically triggers the hydraulic backwash regeneration operation, which solves the problems of lack of online monitoring and automatic regeneration capabilities and high risk of effluent exceeding standards in the purification process in the prior art.

[0015] 4. This invention collects full-process status data such as the estimated moisture content of dewatered sludge, the gas phase temperature of the drying chamber, and the concentration and flow rate of purified influent and effluent, calculates the purification load index, and issues temperature setpoints, target moisture content setpoints, and processing capacity adjustment commands based on the range of the load index. This achieves global data integration and closed-loop coordinated control of the three stages of dewatering, drying, and purification, solving the problem of independent control links and lack of global optimization mechanism in the existing technology.

[0016] 5. This invention constructs a complete closed-loop control link with the control component as the core, from sludge moisture content sensing, drying temperature field regulation, purification load assessment to global collaborative decision-making and execution feedback. This enables the heavy metal polluted sludge treatment device to automatically adjust operating parameters when the properties of the incoming sludge fluctuate and environmental conditions change, taking into account the multi-objective optimization needs of treatment efficiency, effluent quality and operating energy consumption. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0018] Figure 2 This is a schematic diagram of the overall internal structure of the present invention;

[0019] Figure 3 This is a schematic diagram of the overall rear structure of the present invention;

[0020] Figure 4 This is a schematic diagram of the overall system structure of the present invention;

[0021] In the diagram: 1. Support cabinet; 2. Control components; 3. Sealing door; 4. Centrifugal mechanism; 5. Conveying pipe; 6. Drying mechanism; 7. Discharge mechanism; 8. Water storage tank; 9. Purification mechanism; 10. Detector. Detailed Implementation

[0022] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. In addition, the forms of the various structures described in the following embodiments are merely illustrative. The heavy metal polluted sludge treatment device based on environmental protection technology involved in the present invention is not limited to the structures described in the following embodiments. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Please see Figures 1-3 The heavy metal contaminated sludge treatment device based on environmental protection technology includes a support cabinet 1 with a sealed door 3 hinged to its front. A control unit 2 is located on the side of the support cabinet 1. The support cabinet 1 provides a stable installation platform, the sealed door 3 ensures the internal processing is sealed, preventing odors and pollutants from leaking out, and the control unit 2 allows operators to centrally control the equipment. A centrifugal mechanism 4, consisting of a motor, drive wheels, and belt, is fixedly installed inside the support cabinet 1 and opposite to the sealed door 3. The motor drives the drive wheels and belt to rotate the centrifugal components at high speed, using centrifugal force to quickly separate and discharge a large amount of water from the sludge, significantly reducing subsequent drying energy consumption and improving dewatering efficiency. A drying mechanism 6, consisting of a thermometer and a heater, is fixedly installed inside the support cabinet 1 and below the centrifugal mechanism 4. The heater provides a stable heat source for deep drying of the sludge, and the thermometer monitors and provides feedback on the internal temperature in real time, facilitating precise temperature control, preventing over-drying or energy waste, and effectively reducing the volume and weight of the sludge. A conveying pipe 5, with one end connected to the sealed door 3 and the other end connected to the drying mechanism 6, conveys the centrifuged sludge to the drying mechanism 6 in a sealed manner, avoiding... To prevent odor emission and heat loss during material transfer and maintain a clean working environment, the discharge mechanism 7, consisting of a cylinder, a guide plate, and a storage box, is installed inside the support cabinet 1 and located to the side of the drying mechanism 6. The cylinder pushes the guide plate to smoothly guide the dried sludge product into the storage box, achieving automatic and orderly discharge and preventing material accumulation from affecting continuous production. The water storage tank 8, installed inside the support cabinet 1 and located directly below the centrifuge mechanism 4, directly collects the wastewater discharged from the centrifuge mechanism 4, preventing liquid splashing and contamination of the equipment interior, and providing a buffer for subsequent purification treatment. The system includes a purification mechanism 9, consisting of a connecting pipe, a purifier, and valves. It is fixedly installed on the rear side of the support cabinet 1 and connected to the bottom of the water storage tank 8. The valves control the flow direction of the connecting pipe and the purifier, allowing the wastewater containing heavy metals collected in the water storage tank 8 to be filtered and purified multiple times to deeply remove harmful substances, ensuring that the effluent meets environmental discharge or reuse standards and reducing the risk of environmental pollution. A detector 10 is fixedly installed on the side of the purification mechanism 9 to monitor the concentration of residual heavy metals in the purified water in real time, ensuring that the treatment effect meets the standards and realizing data monitoring and safety early warning.

[0024] During the operation, the heavy metal contaminated sludge to be treated enters the support cabinet 1, and the operator starts the equipment through the control unit 2.

[0025] First, the sludge is dewatered in the centrifugal mechanism 4 by a motor-driven transmission wheel and belt. The dewatered wastewater falls into the lower water storage tank 8 for temporary storage. The dewatered sludge is then conveyed to the drying mechanism 6 through the conveying pipe 5 in a sealed manner. The heater in the drying mechanism 6 dries the sludge at a constant temperature under the monitoring of a thermometer. The dried product is then sent to the storage box discharge device by the cylinder-driven guide plate of the discharge mechanism 7. At the same time, the wastewater in the water storage tank 8 enters the purification mechanism 9. Through the connecting pipe and valve regulation, it is filtered and purified multiple times in the purifier. The purified water quality is monitored in real time by the detector 10 to ensure that it meets the discharge standards.

[0026] Working principle:

[0027] The control unit (2) uses an industrial-grade embedded controller as its core hardware platform. It features multi-channel analog / digital signal input / output interfaces, enabling efficient adaptation to peripherals such as moisture content sensors, level gauges, thermometers, heavy metal detectors, electromagnetic flowmeters, weighing sensors, servo motor drivers, and variable frequency pumps. This meets the real-time data acquisition and high-response control requirements of the entire sludge dewatering, drying, and purification process. The software system running on this hardware platform adopts a modular design, such as... Figure 4 As shown, the system includes: a solid-liquid separation and variable load speed-regulating dewatering control module, a multi-temperature zone thermo-mass coupling drying and steam condensation control module, a heavy metal targeted purification and self-regulating regeneration control module, and a load prediction-based feedforward collaborative control module. These modules communicate through clearly defined data interfaces, forming a complete closed loop from sludge moisture content sensing, drying temperature field regulation, purification load assessment to global collaborative decision-making and execution feedback. This achieves integrated intelligent management and control of deep sludge dewatering, energy-saving drying, and heavy metal emission compliance.

[0028] The solid-liquid separation and variable load speed regulation dewatering control module: adaptively generates centrifuge speed commands based on the initial moisture content of the incoming sludge, and determines the timing of switching between dewatering stages in real time, realizing dual-stage variable load control for rapid removal of free water and deep compaction of interstitial water.

[0029] S101: Initial speed feedforward calculation

[0030] Before the sludge enters the centrifuge (4), a microwave transmission type moisture content sensor installed in the feed pipeline is used to... The sampling frequency is used to collect the initial mass and moisture content of the sludge in real time. (Unit: %), and transmitted to this module via analog input channel. The microwave transmission detection method can penetrate sludge material to achieve overall moisture content detection. Compared with contact electrode detection, it is not affected by the surface moisture of sludge or the density of the material, and has higher detection accuracy and faster response speed, which can meet the real-time requirements of feedforward control.

[0031] The module incorporates a piecewise linear feedforward model based on experimental data of sludge dewatering characteristics. When it receives... Then, the module calculates the initial speed command value using the following formula. :

[0032]

[0033] in, =1500r / min and =3800r / min is the minimum and maximum operating speed calibrated by the equipment's mechanical characteristics test. The higher the initial moisture content, the stronger the sludge fluidity. If the initial speed is too high, the sludge is easily thrown out of the drum before being fully dewatered, causing sludge leakage. The lower the initial moisture content, the higher the sludge solid content, requiring a higher centrifugal force to achieve effective solid-liquid separation.

[0034] The module will calculate the result The PWM signal is sent to the centrifugal motor driver via the PWM interface, driving the drum of the centrifugal mechanism (4) to run at this speed.

[0035] S102: Phase Switching Decision

[0036] In the centrifugal motor During constant-speed operation, the pressure level gauge in the water tank (8) measures the liquid level height at a sampling frequency of 1 Hz, and transmits the height sequence through a digital signal interface. Transferred to this module.

[0037] Compared to directly installing a moisture content sensor inside the centrifuge mechanism, indirectly determining the dehydration stage by using the liquid level increment of the water tank can avoid the impact of factors such as high vibration, high humidity, and sludge adhesion inside the centrifuge mechanism on the detection accuracy. At the same time, it eliminates the need to install detection equipment on the rotating parts, reducing the difficulty of hardware installation and the equipment failure rate, and resulting in higher stability and reliability of the detection data.

[0038] The module calculates the liquid level increment per unit time in real time. Internally, a sliding window is maintained to record the average liquid level increment during the first two minutes after dehydration begins. As a benchmark value.

[0039] This benchmark value can characterize the stable dehydration rate during the free water removal stage. When the liquid level increment decreases, it indicates that the free water has been basically removed and the solid-liquid separation enters the interstitial water removal stage.

[0040] When the condition is met for N=10 consecutive sampling periods When the module determines that the free water has been largely removed, its internal state machine switches from "free water removal" to "compaction and interstitial water removal," and records the switching time. .

[0041] S103: Generation of stepped, gradually changing speed command

[0042] After entering the compaction and interstitial water removal stage, the module generates a rotational speed command sequence according to the following time function:

[0043]

[0044] in, = +500 r / min is the initial rotational speed for this stage; =80r / min is the decrease rate for each level; =45s is the duration of each level; ⌊⋅⌋ is the floor function.

[0045] The rotational speed curve is an open-loop feedforward command, and its parameters are determined through offline testing and optimization, without relying on real-time feedback of the dehydration effect.

[0046] Module by The speed control command is updated periodically and sent to the motor driver via the CAN bus. This step-decreasing speed control mode reduces centrifugal force step by step, causing a moderate relaxation effect on the high-pressure compacted sludge flocs, releasing the interstitial water trapped inside the flocs. Then, the flocs are compacted again by the next speed. This repeated "compaction-relaxation-compaction" process can effectively break the hydration structure of the sludge flocs.

[0047] S104: Dehydration Effect Prediction and Data Release

[0048] After the dehydration process is complete, the module determines the initial moisture content. Based on the actual rotation speed-time history, the moisture content of the dewatered sludge is estimated using an empirical regression model:

[0049]

[0050] in, Angular velocity; Let be the dehydration rate coefficient, and take . ; The bound water content is taken as 8%. Total dehydration time.

[0051] This model is built on the principle of centrifugal dewatering dynamics. It can accurately predict the moisture content of sludge after dewatering without the need for online detection of the output moisture content. This provides preliminary data support for setting the temperature field in the subsequent drying process, and realizes the preliminary synergy between the dewatering and drying processes.

[0052] The module will calculate the result The data is published via the internal data bus to the feedforward collaborative control module based on load forecasting for use in drying temperature field regulation.

[0053] The multi-temperature zone thermo-mass coupling drying and steam condensation control module is used for zone setting of the drying temperature field and temperature closed-loop tracking, to determine the drying endpoint in real time based on thermal efficiency, and to control the coordinated operation of the steam condensation system.

[0054] S201: Temperature Zone Power Distribution and Temperature Tracking

[0055] The module directs the drying chamber of the drying mechanism (6) along the material travel direction. ( =2.0m) is divided into three functional zones, and a reference power command is given to each zone.

[0056] Radiant preheating zone (0≤ <0.25 The power command is fixed as follows: =30%.

[0057] Deceleration terminal dry zone (0.75) ≤x≤ Power command The system is dynamically adjusted based on feedback from the output moisture content.

[0058] For the constant rate drying zone (0.25) ≤ <0.75 The multi-point platinum resistance thermometer in the drying mechanism (6) collects the gas phase temperature in a 2s cycle and transmits it to this module through the analog input channel.

[0059] The module publishes the drying temperature setpoint using a feedforward collaborative control module based on load forecasting. To calculate the target value, run the PID closed-loop control algorithm to calculate the heater power command for that area. :

[0060]

[0061] Among them, deviation , The average temperature at multiple points in the area; the PID parameters were tuned through a step response test. =2.5、 =0.02 , =15 Control cycle =2s. Calculated After being limited, the signal is sent to the heater solid-state relay via the analog output interface.

[0062] S202: Steam Condensation Control

[0063] During the drying process, the module keeps the exhaust fan running by default, continuously drawing water vapor from the drying chamber to the steam condenser. The module does not perform closed-loop regulation of the condensation process, and the condenser operates in a continuously circulating cooling water mode. The condensate flows by gravity into the main inlet pipe of the purification unit (9). The activated carbon fiber filter downstream of the condenser serves as a passive protection unit and does not require active control.

[0064] S203: Determination of drying endpoint based on thermal efficiency

[0065] In the deceleration and final drying zone, a weighing sensor located at the front end of the discharge mechanism collects material mass data every 30 seconds and transmits the mass sequence via a digital signal interface. The power is transmitted to this module. Simultaneously, the heater current and voltage monitoring unit will input the power in real time. Feedback is sent to the module.

[0066] The module calculates the thermal efficiency factor periodically. :

[0067]

[0068] in, =2260kJ / kg is the latent heat of vaporization of water; This represents the reduction in material quality between adjacent cycles. This represents the current input power of the heater in this area.

[0069] When detected When <0.3 for three consecutive times, the module determines that drying has reached the economic endpoint and executes the following instructions in sequence: send a shutdown instruction to the heater in the area; send an action pulse instruction to the cylinder solenoid valve of the discharge mechanism (7) to push the dried sludge into the storage box; and issue a drying completion status flag to the feedforward collaborative control module based on load prediction.

[0070] The heavy metal targeted purification and self-regulating regeneration control module is used to monitor the water quality penetration trend during the purification process, automatically trigger hydraulic backwash regeneration based on the degree of adsorption efficiency decay, and determine and warn about the service life of the packing material.

[0071] S301: Penetration Trend Monitoring

[0072] After the wastewater enters the purification unit (9), the online detector located at the outlet of the water storage tank (8) collects the total concentration of heavy metals in the influent at a cycle of 1 minute. (Unit: mg / L), the detector (10) simultaneously collects the total concentration of heavy metals in the effluent. (Unit: mg / L), both are transmitted to this module via the analog input channel. At the same time, the electromagnetic flow meter installed in the purification pipeline transmits the real-time influent flow rate Q (unit: L / min) to the module.

[0073] Module reading After sequencing, the concentration decay rate coefficient was calculated. :

[0074]

[0075] in =1min. This represents the rate of concentration decrease per unit concentration at the current moment. A decrease in this value indicates a decrease in the adsorption driving force, and the packing layer tends to penetrate.

[0076] S302: Hydraulic backflush trigger

[0077] The module internally maintains a backflash trigger determination state machine. When two consecutive checks (10 minutes apart) detect... <0.005 At this time, the state machine enters the recoil preparation state. The module executes the following instruction sequence in sequence:

[0078] The system outputs a switching command to the valve actuator to close the main inlet and outlet valves of the purified water system and open the backwash circuit valve, connecting the outlet of the secondary purifier to the outlet of the primary purifier via the backwash pump. Once the valve status feedback signal confirms the connection, a speed command corresponding to the flow rate is sent to the backwash pump inverter. Duration .

[0079] After backflushing, the module sequentially closes the backflushing loop valve, stops the backflushing pump, and restores the forward inlet valve, returning the system to normal adsorption mode. The concentrated water generated by backflushing flows back to the storage tank (8) via a dedicated return pipeline, allowing the stripped heavy metals to re-enter the wastewater stream to be treated and be further removed in the next purification cycle.

[0080] S303: Packing Failure Judgment

[0081] The module accumulates and counts the number of recoil cycles. After each backflushing cycle, the module continues to monitor the concentration of the effluent after the forward flow. .

[0082] when 3 and Still exceeds the preset emission standard limit When the total lead concentration is 0.1 mg / L or the total cadmium concentration is 0.01 mg / L, the module determines that the filler function has irreversibly degraded. It then triggers an audible and visual alarm device through the digital output interface and issues a fault flag for the heavy metal targeted purification and self-regulating regeneration control module to the feedforward collaborative control module based on load prediction.

[0083] The feedforward collaborative control module based on load forecasting is used to integrate the status data of each sub-module, calculate the system-level purification load index, and issue operating parameter setpoints to each sub-module accordingly to achieve global collaborative control.

[0084] S401: Global Status Data Acquisition and Load Index Calculation

[0085] The module operates in a 60-second control cycle. At the beginning of each cycle, the module obtains the following state variables from each submodule via the internal data bus: estimated moisture content of the dewatered sludge. The weighted average temperature of the entire drying chamber, obtained by weighting the gas phase temperatures collected in the radiation preheating zone, constant-rate drying zone, and falling-rate final drying zone, is used as the current value of the gas phase temperature in the drying chamber. ; Purification of influent concentration ; Purified water concentration ; Purification influent flow rate Q; Sludge treatment capacity The data is collected in real time by a feed belt scale located at the front end of the feed pipeline and transmitted via a digital signal interface.

[0086] The module calculates the current dimensionless purification load index L_p using the following formula:

[0087]

[0088] in, =3.0min is the design hydraulic retention time, which is determined by the purifier's pore volume. Design reference flow Sure; The average saturated adsorption capacity of the packing material for mixed heavy metals was determined by isothermal adsorption test. =25000g is the total mass of the packing material.

[0089] After dimension verification, the result of this formula is a dimensionless pure number, and its value range usually falls in the interval [0,1]. The higher the value, the closer the heavy metal targeted purification and self-regulating regeneration control module is to its design processing capacity limit.

[0090] S402: Coordinated Regulation Rule Calculation and Command Issuance

[0091] Module according to The calculated values ​​are used to determine the operating parameter settings of each submodule according to the preset segmented adjustment rules, and are then sent down in real time through the internal data bus.

[0092] when When the value is less than 0.5, the module determines that the purification capacity is sufficient. A control order is then issued to the multi-temperature zone thermo-mass coupling drying and steam condensation control module. Temperature setpoint; issued to the solid-liquid separation and variable load speed regulation dehydration control module The target moisture content; no adjustment to the feed rate.

[0093] when At that time, the module determined that the heavy metal targeted purification and self-regulating regeneration control module had entered a medium load state. It then issued a command to the multi-temperature zone thermo-mass coupling drying and steam condensation control module. Send to the solid-liquid separation and variable load speed regulation dehydration control module The feed rate remains unchanged. The logic of this adjustment strategy is as follows: by increasing the dehydration intensity, the total amount of moisture evaporated during the drying stage is reduced, thereby reducing the amount of condensate generated, which in turn reduces the hydraulic load on the heavy metal targeted purification and self-regulating regeneration control module.

[0094] when At 85:00, the module determined that the heavy metal targeted purification and self-regulating regeneration control module had entered a high-load state. A command was issued to the multi-temperature zone thermo-mass coupling drying and steam condensation control module. Send to the solid-liquid separation and variable load speed regulation dehydration control module Simultaneously, instructions are sent to the feeding system to adjust the sludge processing volume. Reduced to 85% of the rated value.

[0095] when At this time, the module determines that the system has entered conservative mode, prioritizing ensuring that the effluent water quality meets the standards. It then issues a control order to the multi-temperature zone thermo-mass coupling drying and steam condensation module. Send to the solid-liquid separation and variable load speed regulation dehydration control module The system issues a command to the feeding system to reduce the sludge treatment capacity to 70% of the rated value.

[0096] S403: Feedback Correction and System Stability

[0097] In addition to feedforward coordinated regulation, each module has an independent feedback control loop. The multi-temperature zone thermo-mass coupling drying and steam condensation control module tracks the temperature setpoint using a PID algorithm, while the solid-liquid separation and variable load speed regulation dehydration control module tracks the temperature setpoint based on real-time detection. Fine-tune the rotational speed based on the deviation from the target value. The module continuously monitors this. The changing trend, if for three consecutive cycles If the level continues to rise and exceeds the threshold, higher-level adjustment measures will be triggered in advance to ensure that the system can still operate stably when the properties of the incoming sludge fluctuate and environmental conditions change.

[0098] Through the division of labor and collaboration of the above four software modules, the control component (2) realizes the closed-loop control of perception, decision-making, execution and feedback of the entire sludge treatment process, and takes into account the system processing efficiency and operating energy consumption while ensuring that heavy metal emissions meet the standards.

[0099] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0100] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A heavy metal contaminated sludge treatment device based on environmental protection technology, comprising a support cabinet (1) with a sealing door (3) hinged to its front side, and a control component (2) provided on the side of the support cabinet (1); a centrifugal mechanism (4) fixedly installed inside the support cabinet (1) and opposite to the sealing door (3); a drying mechanism (6) fixedly installed inside the support cabinet (1) and located below the centrifugal mechanism (4); a conveying pipe (5) with one end connected to the sealing door (3) and the other end connected to the drying mechanism (6); a discharge mechanism (7) installed inside the support cabinet (1) and located on the side of the drying mechanism (6); a water storage tank (8) installed inside the support cabinet (1) and located directly below the centrifugal mechanism (4); a purification mechanism (9) fixedly installed on the rear side of the support cabinet (1) and connected to the bottom of the water storage tank (8); and a detector (10) fixedly installed on the side of the purification mechanism (9).

2. The heavy metal contaminated sludge treatment device based on environmental protection technology according to claim 1, characterized in that, The control element (2) includes: The solid-liquid separation and variable load speed regulation dewatering control module is used to generate centrifuge speed commands based on the initial moisture content of the incoming sludge, and to determine the switching of the dewatering stage based on the change in liquid level increment to execute variable load control. After the dewatering is completed, it outputs the estimated moisture content of the sludge. The multi-temperature zone thermo-mass coupling drying and steam condensation control module is used to receive the drying temperature setpoint and perform zoned temperature closed-loop tracking accordingly, and calculate the thermal efficiency factor based on the material mass change to determine the drying endpoint. The heavy metal targeted purification and self-regulating regeneration control module is used to calculate the concentration decay rate coefficient based on the heavy metal concentration in the effluent, trigger hydraulic backwash regeneration when the coefficient is lower than the threshold, and output the purified effluent concentration and influent flow rate data. The feedforward collaborative control module based on load prediction is used to receive the estimated sludge moisture content, drying chamber gas phase temperature, purified influent concentration, purified effluent concentration and influent flow rate data, calculate the purification load index, and send the drying temperature setpoint to the multi-temperature zone thermo-mass coupling drying and steam condensation control module and the target moisture content setpoint to the solid-liquid separation and variable load speed regulation dewatering control module according to the range of the purification load index.

3. The heavy metal contaminated sludge treatment device based on environmental protection technology according to claim 2, characterized in that, The solid-liquid separation and variable load speed regulation dehydration control module includes: real-time acquisition of the liquid level height sequence in the water storage tank and calculation of the liquid level increment per unit time; using the average liquid level increment within a preset time period after the start of dehydration as a reference value; when the liquid level increment per unit time within a consecutive preset number of sampling periods drops below a preset proportion of the reference value, determining that the free water removal stage has ended and switching to the compaction and interstitial water removal stage; in the compaction and interstitial water removal stage, generating a speed command sequence according to a preset step-decreasing time function to gradually reduce the speed of the centrifuge mechanism.

4. The heavy metal contaminated sludge treatment device based on environmental protection technology according to claim 3, characterized in that, The stepped decreasing time function includes: after entering the compaction and interstitial water removal stage, starting from the initial rotation speed of the stage, the current rotation speed command is reduced by a preset decreasing amount every preset duration until the dehydration process ends; wherein, the initial rotation speed of the stage is the initial rotation speed command value increased by 500 revolutions per minute, the decreasing amount of each stage is 80 revolutions per minute, and the duration of each stage is 45 seconds.

5. A heavy metal contaminated sludge treatment device based on environmental protection technology according to claim 2, characterized in that, The multi-temperature zone thermo-mass coupling drying and steam condensation control module includes: dividing the drying chamber into a radiation preheating zone, a constant-speed drying zone, and a falling-speed final drying zone along the material travel direction; performing closed-loop temperature tracking control on the constant-speed drying zone based on the received drying temperature setpoint; and calculating a thermal efficiency factor to characterize the drying efficiency based on the change in material mass over time in the falling-speed final drying zone, and determining the drying endpoint when the thermal efficiency factor is continuously lower than a preset threshold multiple times, triggering a drying stop command and a material discharge command.

6. A heavy metal contaminated sludge treatment device based on environmental protection technology according to claim 5, characterized in that, The thermal efficiency factor includes: obtaining the latent heat of vaporization of water, the decrease in material mass within two adjacent sampling periods, and the current input power of the heater in the drying zone; multiplying the latent heat of vaporization of water by the decrease in material mass and dividing by the sampling time interval to obtain the heat required for water evaporation; and then using the ratio of the heat required for water evaporation to the current input power of the heater as the thermal efficiency factor.

7. A heavy metal contaminated sludge treatment device based on environmental protection technology according to claim 2, characterized in that, The heavy metal targeted purification and self-regulating regeneration control module includes: The concentration of heavy metals in the effluent is collected at a preset period, and the concentration decay rate coefficient is calculated based on the rate of change of the difference between the concentration value at the current moment and the concentration value at the previous moment relative to the concentration value at the current moment. When the concentration decay rate coefficient is found to be lower than the preset rate threshold after two consecutive tests with a preset interval, the following backflushing operations are performed in sequence: closing the main inlet valve and the main outlet valve of the purification system, opening the backflushing circuit valve, starting the backflushing pump, and setting the backflushing flow rate to 1.8 times the forward inlet flow rate. The backflushing operation continues for a preset duration and then the forward inlet mode is restored. The number of backflushing cycles is accumulated. When the number of cycles reaches or exceeds the preset number and the concentration of heavy metals in the effluent is still higher than the discharge standard limit, it is determined that the packing function has irreversibly deteriorated and an alarm signal is issued.

8. A heavy metal contaminated sludge treatment device based on environmental protection technology according to claim 7, characterized in that, The backwash operation includes: closing the main inlet valve and the main outlet valve of the purifier, opening the backwash loop valve to connect the outlet of the secondary purifier with the outlet of the primary purifier through the backwash pump, starting the backwash pump after confirming that the valve status is in place, and performing backwashing according to the preset backwash flow rate and preset duration, closing the backwash loop valve and stopping the backwash pump after the backwash is completed, restoring the status of the forward inlet valve to return to the normal purification mode, and the concentrated water generated by backwashing flows back to the water storage tank by gravity through a dedicated return pipeline.

9. A heavy metal contaminated sludge treatment device based on environmental protection technology according to claim 2, characterized in that, The feedforward collaborative control module based on load forecasting includes: Obtain the estimated moisture content of dewatered sludge, the current value of the gas phase temperature in the drying chamber, the concentration of purified influent, the concentration of purified effluent, the flow rate of purified influent, and the sludge treatment volume; The current purification load index is calculated based on the influent concentration, influent flow rate, saturated adsorption capacity of the packing material, total mass of the packing material, and the ratio of effluent concentration to influent concentration. When the purification load index is less than 0.5, a first drying temperature setting value is issued to the drying mechanism and a first target moisture content setting value is issued to the centrifugal mechanism. When the purification load index is between 0.5 and 0.7, a second drying temperature setting value is issued to the drying mechanism, and a second target moisture content setting value is issued to the centrifugal mechanism. When the purification load index is between 0.7 and 0.85, a third drying temperature setting value is issued to the drying mechanism, a third target moisture content setting value is issued to the centrifugal mechanism, and an instruction is issued to the feeding system to reduce the sludge treatment capacity to 85% of the rated value. When the purification load index is greater than or equal to 0.85, a fourth drying temperature setting value is issued to the drying mechanism, a fourth target moisture content setting value is issued to the centrifugal mechanism, and an instruction is issued to the feeding system to reduce the sludge treatment capacity to 70% of the rated value.

10. A heavy metal contaminated sludge treatment device based on environmental protection technology according to claim 9, characterized in that, The calculation of the purification load index includes: obtaining the influent concentration, influent flow rate, purifier design hydraulic retention time, average saturated adsorption capacity of the packing for mixed heavy metals, total mass of the packing, and the ratio of the effluent concentration to the influent concentration; multiplying the product of the influent concentration, influent flow rate, and design hydraulic retention time by the product of the average saturated adsorption capacity and the total mass of the packing by the reciprocal correction term of the ratio of the effluent concentration to the influent concentration to obtain the purification load index.

Images