CN-121974534-A - Multistage centrifugal dewatering type sludge comprehensive treatment method and system

CN121974534ACN 121974534 ACN121974534 ACN 121974534ACN-121974534-A

Abstract

The invention provides a multistage centrifugal dewatering type sludge comprehensive treatment method and a system, which relate to the technical field of sludge treatment, wherein the method comprises the steps of pretreating raw sludge through a mechanical grid and magnetic separation; the method comprises the steps of feeding pretreated sludge into a multistage centrifugal dehydration unit with rotating speed gradient increasing, dynamically adding chemical or biological conditioning agents based on a dynamic adaptive function between stages, cooperatively regulating dehydration and floc modification, feeding the dehydrated sludge into a closed hot air circulation drying device, optimizing drying parameters by using a multi-objective optimization function, realizing efficient low-consumption drying, extruding the dried sludge into fuel rods or organic fertilizer base materials based on a collaborative decision index, correspondingly comprising modules of pretreatment, multistage dehydration and conditioning, hot air drying, extrusion molding and the like, and realizing intelligent cooperative control and global optimization of the process parameters of each unit by constructing a process state holographic sensing network.

Inventors

XIE HUAIMING
Tang Songzhe
ZENG LIXIN
YANG HUA
HE JINGHUI
WU YUANZHAO
ZHANG XUHANG
Wu Ciyun

Assignees

广州市哲恒环境科技股份有限公司

Dates

Publication Date: 20260505
Application Date: 20260120

Claims (10)

1. The multistage centrifugal dewatering type sludge comprehensive treatment method is characterized by comprising the following steps of: S1, pumping primary sludge generated by municipal sewage plants or industrial wastewater treatment systems into a receiving tank, intercepting solid impurities including plastic fragments, fiber and gravel through a mechanical grid, removing iron-containing magnetic impurities in the sludge by adopting a permanent magnet separator to obtain pretreated sludge, and uniformly conveying the pretreated sludge to a homogenizing adjustment tank for temporary storage; S2, conveying pretreated sludge into three-stage to five-stage serial centrifugal dehydration units through screw pumps, wherein the rotation speed of each stage of centrifugal dehydrator is gradually increased along the sludge flow direction, the rotation speed of a first-stage centrifugal machine is 800-1200 rpm, the rotation speed of a second-stage centrifugal machine is increased to 1500-2000 rpm, and the rotation speed of a third-stage centrifugal machine and above is gradually increased to 2500-3200 rpm; S3, conveying the sludge subjected to multistage centrifugal dehydration to a closed hot air circulation drying device, wherein a drying system is provided with a waste heat recovery device, and circulating outlet hot air to an inlet, so that energy consumption is reduced, and the generated waste gas is condensed and dehumidified and then discharged after reaching standards; S4, feeding the dried sludge into a double-screw extrusion molding device, and carrying out plastic extrusion at the temperature of 60-80 ℃ and the pressure of 3-5 megapascals to prepare the fuel rod with the diameter of 30-50 millimeters or the organic fertilizer base stock with the particle size of 2-5 millimeters.
2. The method of claim 1, wherein the chemical conditioning agent in the step S2 is a compound system of polyaluminium chloride and cationic polyacrylamide, the adding amount is calculated according to 0.1-0.5% of the dry mass of the sludge, the biological bacterial agent is a compound bacillus preparation, the adding amount is 0.05-0.1% of the volume of the sludge, the conditioning reaction time is 15-30 minutes, the drying temperature in the step S3 is controlled at 105-120 ℃, and the hot air speed is maintained at 1.2-1.8 meters per second.
3. The method of claim 1, wherein step S1 comprises the steps of: s11, continuously pumping primary sludge generated by municipal sewage plants or industrial wastewater treatment systems into a receiving tank through a sludge conveying pump; s12, enabling sludge in the receiving pool to flow through a mechanical grid, and intercepting and removing solid impurities with the particle size of more than or equal to 5mm, wherein the solid impurities comprise plastic fragments, fiber matters and gravel; S13, introducing the sludge subjected to the grid treatment into a permanent magnet separator, and removing magnetic impurities containing iron in the sludge under the magnetic field intensity of 0.8 to 1.2 Tesla; S14, obtaining pretreated sludge, wherein the water content of the pretreated sludge is reduced to 99.2-99.5%, and uniformly conveying the pretreated sludge to a homogenizing adjusting tank for temporary storage so as to carry out subsequent treatment.
4. The method of claim 1, wherein step S2 comprises the steps of: S21, carrying out on-line quantification on the property parameters of the pretreated sludge from the homogenizing adjustment tank to obtain an input sludge characteristic parameter set, wherein each sludge sample batch in the set corresponds to a characteristic vector, and the characteristic vector comprises an actual measurement value of organic matter content, real-time water content, an electrochemical impedance phase angle and sludge temperature; S22, defining a reaction mechanism and a target of inter-stage conditioning in a multistage centrifugal dehydration unit, wherein the reaction mechanism comprises electric neutralization and adsorption bridging action initiated by a chemical conditioner and extracellular polymer hydrolysis and recombination action catalyzed by a composite biological microbial agent, and the conditioning target is to enable the average particle size of sludge flocs to be increased to 80-120 microns and form a compact floc structure with high mechanical strength; S23, constructing a state transfer and coupling relation model among the multistage dewatering units, taking the solid content and the floc strength of the outlet sludge of the former-stage centrifugal dewatering machine as input conditions of a later-stage conditioning reaction tank, and taking the torque and the differential parameter of the later-stage centrifugal dewatering machine as feedback variables of the rotation speed setting of the former-stage centrifugal machine to form a state association network among the series-connected units; And S24, uniformly describing and executing rotational speed gradient regulation and flocculation modification cooperation through a dynamic adaptation function based on input sludge characteristic parameters, an inter-stage regulation mechanism and a multi-stage state association network, wherein the dynamic adaptation function calculates optimal conditioner adding amount according to real-time sludge properties, and the dynamic adaptation function is based on a sludge organic matter content actual measurement value, an organic matter content reference threshold value, the real-time water content of the sludge at the inlet of a current-stage dewatering unit, the target water content expected to be achieved after the stage regulation and dewatering, and a basic adding coefficient and an adjustment weight factor determined according to the sludge type.
5. The method of claim 1, wherein step S3 comprises the steps of: S31, receiving dehydrated sludge output from a multistage centrifugal dehydration unit, and carrying out state representation before drying to form a drying input state vector, wherein the drying input state vector comprises a sludge solid content actual measurement value, a sludge specific heat capacity, an initial temperature, a volatile organic matter content and a floc structural strength index; S32, defining a process state space of the closed type hot air circulation drying device, wherein the process state space takes drying temperature, hot air speed, drying time and tail gas circulation rate as core control variables, and takes sludge water content, unit evaporation heat consumption and dried sludge particle strength as key performance indexes; S33, constructing a drying process multi-objective optimization function with the energy consumption minimization and the dehydration efficiency maximization as targets, wherein the function carries out weighted fusion on the drying speed, the unit water evaporation energy consumption and the quality stability of a drying product, the multi-objective optimization function is based on the drying temperature, the hot air speed, the drying time and the tail gas circulation rate, and a temperature effect index term, a reciprocal term of the unit water evaporation energy consumption and a product strength variation coefficient are introduced to realize unified quantification and synchronous optimization on three targets of speed, energy consumption and quality; S34, searching in a four-dimensional constraint space formed by drying temperature 105-120 ℃, hot air speed 1.2-1.8 m/S, drying time and tail gas circulation rate by adopting a self-adaptive downhill simplex method aiming at a multivariable strong coupling system based on the multi-objective optimization function, dynamically adjusting searching step length and direction according to a sludge moisture content reduction curve and instantaneous energy consumption data acquired in real time, and outputting an optimal control parameter combination for maximizing a comprehensive optimization evaluation value; And S35, driving the closed type hot air circulation drying device to execute a deep drying process according to the obtained optimal control parameter combination, and realizing closed loop feedback control through a high-precision temperature sensor and an anemometer to ensure that the deviation of the actual drying temperature, the hot air speed and the optimal set value is not more than plus or minus 1 ℃ and plus or minus 0.1 m/S respectively until the water content of the sludge is stably reduced to 10% or below, thereby completing a drying stage.
6. The method of claim 1, wherein step S4 comprises the steps of: s41, receiving the dried sludge output from the closed type hot air circulation drying device, and carrying out characteristic analysis before recycling on the dried sludge to form a molding raw material state vector, wherein the molding raw material state vector comprises the water content, ash content, heat value, cellulose content and flow index of the dried sludge; s42, constructing a recycling decision model for two target products of a fuel rod and an organic fertilizer base stock, wherein the model takes information of the structural strength of the flocs represented by the optimal conditioner addition calculated by the dynamic adaptation function in the previous step S2 and information of drying efficiency and energy consumption contained in the comprehensive optimization evaluation value output by the multi-target optimization function in the step S3 as decision input factors to establish a collaborative decision index; S43, defining a collaborative decision index calculation function which carries out nonlinear fusion on conditioning effect, drying quality and target product quality requirements, wherein the collaborative decision index is calculated based on floc structure modification strength, organic matter characteristics, heat energy utilization efficiency of a drying process, actual measurement of high-order heat value of dried sludge, heat value conversion efficiency when formed into a fuel rod and agricultural safety index when formed into an organic fertilizer base material; S44, setting specific technological parameters of the double-screw extrusion molding device according to the numerical value of the collaborative decision index, controlling the temperature to be 70-80 ℃ and the pressure to be 4-5 MPa if the decision is to prepare the fuel rod, controlling the temperature to be 60-70 ℃ and the pressure to be 3-4 MPa if the decision is to prepare the organic fertilizer base material; S45, cooling and screening the molded product to obtain a final product, wherein the diameter of the final product is 30-50 mm, the heat value of the final product is not lower than 12 MJ/kg in the case of a fuel rod, the particle size of the final product is 2-5 mm in the case of an organic fertilizer base material, the final product meets the relevant agricultural standard, and the whole molding process is linked with the upstream dehydration and drying process through a distributed control system to ensure the seamless execution of decision instructions and technological parameters.
7. The method of claim 1, further comprising the step of: S5, in the whole treatment process, integrating an electrochemical impedance meter and a control system to monitor an electrochemical parameter DS/FC value of the sludge in real time, and calculating and predicting an optimal addition amount difference value of the chemical conditioner through a dynamic slope to realize the self-optimization of the addition amount; s6, the filtrate and the desiccation condensed water generated in the dehydration process flow back to the front end of the sewage treatment system, the extruded fuel rods or fertilizer base materials are conveyed to a storage bin through a belt conveyor for industrial combustion or soil improvement, the system adopts a modularized design, and all units are linked through an Internet of things platform to realize digital monitoring of energy consumption and medicine consumption.
8. The method of claim 7, wherein step S5 comprises the steps of: S51, constructing a process state holographic sensing network, wherein the network takes process parameters, equipment running states and material property data acquired in real time in the steps S2, S3 and S4 as input nodes, the input nodes comprise real-time rotating speed and torque of centrifugal dehydrators at all levels, medicament adding rate and stirring power of a conditioning reaction tank, hot air temperature and wind speed of a drying device, temperature and pressure of a double-screw extruder, sludge organic matter content monitored on line, real-time water content, electrochemical parameters, heat value after drying and molded product strength, and each node is related to a material batch number through a time stamp; S52, defining a correlation edge and a dynamic weight of a process state holographic sensing network, wherein the correlation edge is used for representing the transfer and coupling relation of materials, energy and information flow among different process units, the dynamic weight is adaptively adjusted according to the real-time process efficiency, and the calculation of the dynamic weight depends on the deviation between the optimal addition amount and the actual addition amount obtained by the dynamic adaptation function in the step S2, the real-time state of the comprehensive evaluation value obtained by the multi-objective optimization function in the step S3 and the indication of the collaborative decision index to the current production route in the step S4; S53, training a process state holographic sensing network, taking optimal operation state data of each process unit in a preamble steady operation period as a supervision signal, taking minimized global operation cost and maximized comprehensive product quality as combined optimization targets, training dynamic weight parameters in the network, and enabling the network to learn and memorize a regulating and controlling mode for maintaining global optimal system under multivariate disturbance by adopting a time sequence back propagation algorithm in the training process; S54, performing online real-time regulation and self-optimization based on a trained process state holographic sensing network, inputting process node data acquired in real time into the network, and outputting an optimized set value set for the next control period through forward propagation calculation by the network, wherein the set comprises a fine adjustment amount of rotational speed gradient of each level of centrifugal machine, a compensation value of dosing amount of a conditioning agent, a correction value of temperature and wind speed of a drying device and a preset value of forming process parameters; step S6 includes the steps of: S61, realizing the directional reflux of byproducts and the intelligent scheduling of recycled products, and uniformly collecting filtrate generated in the dehydration process, condensed water generated in the drying process and equipment cleaning wastewater into a reflux regulating tank; the water quality online monitoring system analyzes key pollutant indexes in the reflux liquid in real time, and pumps the reflux liquid back to a front-end biochemical treatment unit or a deep treatment unit of the sewage treatment system according to a preset proportion and concentration through an internet of things platform instruction regulating valve; s62, establishing a resource product storage and distribution system based on full-flow quality tracing, and endowing unique tracing codes for fuel rods or organic fertilizer base materials produced by each batch, wherein the unique tracing codes relate all key process parameters and quality data of the steps S2 to S4 in the production process; S63, constructing a digital monitoring and global decision platform which integrates the sensors of the Internet of things, the control system and the holographic sensing network of the process state of each process unit, wherein the platform dynamically and visually displays real-time energy consumption, real-time medicine consumption, processing efficiency, product yield and quality indexes; S64, executing full-process closed-loop management and self-adaptive evolution, evaluating the global operation efficiency of the system by the digital monitoring platform weekly or monthly according to the average unit energy consumption, the average medicament consumption, the product standard reaching rate and the comprehensive efficiency of equipment, and when the evaluation value deviates from the reference line, automatically starting a retraining process of the process state holographic sensing network by the platform, and fine-tuning the dynamic weight of the process state holographic sensing network by utilizing recent data.
9. A multistage centrifugal dewatering sludge blanket system for implementing the method of any of claims 1-8, comprising: The sludge pretreatment module is used for receiving the primary sludge and performing primary purification, and comprises a mechanical grid for intercepting solid impurities and a permanent magnet for removing magnetic impurities to obtain pretreated sludge with the water content reduced to 99.2-99.5%, and temporarily storing the pretreated sludge in the homogenizing adjustment tank; The multistage centrifugal dehydration and conditioning module is used for carrying out gradient dehydration on the pretreated sludge through multistage serial centrifugal dehydration units, carrying out dynamic conditioning on the pretreated sludge between stages, and improving the solid content to 25% -35% through modifying sludge flocs by chemical conditioning agents or biological bacterial agents; The hot air circulation drying module is used for performing closed hot air drying on the dehydrated sludge, controlling the drying temperature and the air speed, reducing the water content to below 10%, and integrating waste heat recovery and waste gas treatment; And the extrusion molding and recycling module is used for extruding and molding the dried sludge through double screws, selectively preparing fuel rods or organic fertilizer base materials, and adjusting technological parameters according to recycling requirements.
10. The system as recited in claim 9, further comprising: The real-time monitoring and self-optimizing module is used for monitoring sludge properties and equipment states in real time through a holographic sensing network, dynamically adjusting process parameters and realizing the collaborative optimization of dehydration efficiency and energy consumption; and the byproduct management and digital monitoring module is used for processing the backflow of filtrate and condensed water, managing the storage and distribution of the resource products and carrying out full-flow digital monitoring through the Internet of things platform.

Description

Multistage centrifugal dewatering type sludge comprehensive treatment method and system Technical Field The invention relates to the technical field of sludge treatment, in particular to a multistage centrifugal dewatering type comprehensive sludge treatment method and system. Background In the actual operation of municipal sewage plants, sludge treatment is a key link for ensuring the stable standard reaching of the whole plant, however, in a rainy season or an urban pipe network converging area, a large amount of surface flushing matters, industrial wastewater and domestic sewage are mixed, so that the original sludge entering the sewage plants is complex in components and severe in property fluctuation, the fluctuation forms a great challenge for subsequent dehydration treatment, single chemical conditioning is often adopted in the prior art, belt filter pressing or centrifugal dehydration is combined, the operation mode of the fixed parameters is difficult to adapt to the real-time change of the organic matter content and viscosity in the sludge, operators often rely on experience to manually adjust the dosage of the medicament in the actual scene, serious hysteresis exists, the unstable dehydration effect is caused directly, filter cloth blockage, torque surge and even shutdown are easy to occur when the sludge property is suddenly changed, the water content of a mud cake after dehydration is always rebounded to be higher than the design requirement, the entering standard of subsequent treatment such as incineration or landfill cannot be met, meanwhile, the rough control mode also causes the medicament waste and the excessive energy consumption is single, the dehydrated sludge is directly sent to the landfill site in a plurality of stages, the environment resources are not occupied, and the urgent comprehensive method for realizing the urgent and comprehensive dewatering system has urgent requirements. Disclosure of Invention The invention aims to provide a multistage centrifugal dewatering type sludge comprehensive treatment method and a multistage centrifugal dewatering type sludge comprehensive treatment system, which are used for solving the problems that sludge property fluctuation cannot be adapted in real time due to a fixed parameter operation mode, dewatering efficiency is unstable, chemical conditioner waste and comprehensive energy consumption are high, a recycling path is single, the added value of products is low and the like in the prior art, and the specific technical scheme is as follows: The invention provides a multistage centrifugal dewatering type sludge comprehensive treatment method, which comprises the following steps: S1, pumping primary sludge generated by municipal sewage plants or industrial wastewater treatment systems into a receiving tank, intercepting solid impurities including plastic fragments, fiber and gravel through a mechanical grid, removing iron-containing magnetic impurities in the sludge by adopting a permanent magnet separator to obtain pretreated sludge, and uniformly conveying the pretreated sludge to a homogenizing adjustment tank for temporary storage; S2, conveying pretreated sludge into three-stage to five-stage serial centrifugal dehydration units through screw pumps, wherein the rotation speed of each stage of centrifugal dehydrator is gradually increased along the sludge flow direction, the rotation speed of a first-stage centrifugal machine is 800-1200 rpm, the rotation speed of a second-stage centrifugal machine is increased to 1500-2000 rpm, and the rotation speed of a third-stage centrifugal machine and above is gradually increased to 2500-3200 rpm; S3, conveying the sludge subjected to multistage centrifugal dehydration to a closed hot air circulation drying device, wherein a drying system is provided with a waste heat recovery device, and circulating outlet hot air to an inlet, so that energy consumption is reduced, and the generated waste gas is condensed and dehumidified and then discharged after reaching standards; S4, feeding the dried sludge into a double-screw extrusion molding device, and carrying out plastic extrusion at the temperature of 60-80 ℃ and the pressure of 3-5 megapascals to prepare the fuel rod with the diameter of 30-50 millimeters or the organic fertilizer base stock with the particle size of 2-5 millimeters. Further, in the step S2, the chemical conditioner is a compound system of polyaluminium chloride and cationic polyacrylamide, the adding amount is calculated according to 0.1% -0.5% of the dry basis weight of the sludge, the biological agent is a compound bacillus preparation, the adding amount is 0.05% -0.1% of the volume of the sludge, the conditioning reaction time is 15-30 minutes, the drying temperature in the step S3 is controlled at 105-120 ℃, and the hot air speed is maintained at 1.2-1.8 meters per second. Further, step S1 includes the steps of: s11, continuously pumping primary sludge generated by municipal se