A system and method for treating waste screen residue from aged garbage.

Abstract

This invention discloses a system and method for treating oversize material from aged waste. The system includes a pretreatment unit, a multi-stage screening and sorting unit, a collaborative control unit, and a resource utilization unit. The pretreatment unit crushes the aged waste to generate crushed material. The multi-stage screening and sorting unit is connected to the pretreatment unit and uses multiple screening devices and multiple air separators to perform multi-stage particle size screening and gravity separation on the crushed material, obtaining various types of sorted material. The collaborative control unit acquires real-time images through an image acquisition device, and the control device identifies blockage and flow status and outputs collaborative adjustment signals. The resource utilization unit is connected to the multi-stage screening and sorting unit and converts the sorted material into recycled products according to a preset path. Through the integrated and collaborative design of these four units, this invention achieves efficient sorting, intelligent and stable control, and diversified resource utilization of oversize material from aged waste, forming a complete systematic treatment system and improving treatment efficiency and resource benefits.

Description

Technical Field

[0001] This invention relates to the field of solid waste treatment technology, and in particular to a system and method for treating the residue on screens of aged garbage. Background Technology

[0002] With the acceleration of urbanization and the in-depth advancement of zero-waste city construction in my country, the remediation of historical informal or simple landfills has become urgent. Statistics show that the total amount of garbage accumulated in my country over the years has exceeded 6 billion tons. These garbage mountains not only encroach on valuable land resources but also pose a continuous pollution threat to the surrounding soil, groundwater, and atmospheric environment. In-situ excavation and screening disposal technology has become the mainstream remediation solution due to its ability to completely eliminate pollution risks and release land resources. The core of this technology lies in separating aged waste into different components through a screening system for resource utilization. The screening process typically produces undersize material, mainly composed of humus, and oversize material, mainly composed of lightweight combustibles such as plastics, textiles, and wood blocks, as well as a small amount of inert matter.

[0003] However, existing technologies for treating oversize materials have several significant and unresolved problems: outdated screening processes result in low sorting efficiency and accuracy. Traditional screening methods often employ single drum screens or vibrating screens, lacking targeted equipment combinations and process adaptation designs. When processing complex, high-moisture, and easily agglomerated aged waste, problems such as screen clogging and material entrainment easily occur. In some areas, the average moisture content of aged waste reaches 39.82%, while the industry's conventional screening efficiency is only around 60%, and the impurity content of light materials is as high as 15% or more, directly affecting the quality and economic value of subsequent resource utilization. Furthermore, the resource utilization pathway is singular, and the value has not been fully explored. Currently, the most common disposal method for oversize materials is the preparation of waste-derived fuels. Fuel (RDF) is sent to incineration plants for co-combustion, but due to low sorting accuracy, the calorific value of the prepared RDF is unstable, and the chlorine and sulfur content fluctuates greatly, leading to increased operating costs for incineration plants. At the same time, other high-value components cannot be effectively separated. The level of intelligence is low, and there is a high dependence on manual labor. The automation level of existing screening production lines is generally low, and there is no closed-loop control system for real-time monitoring and dynamic parameter adjustment. Fault handling depends on manual labor, the working environment is harsh and there are safety risks, and the operating parameters cannot be adjusted in real time according to the characteristics of the incoming materials. There is a lack of systematic integration and poor synergy. Existing technologies often focus on a single link and lack a systematic integration scheme for refined screening and diversified utilization. Each processing unit is independent, the resource recovery rate is low, the unit waste treatment cost is high, and the resource recovery benefits are meager. Summary of the Invention

[0004] This invention provides a system and method for treating oversize material from aged waste, which solves the technical problem that existing technologies for treating oversize material from aged waste lack the systematic and comprehensive disposal capabilities that take into account efficient sorting, intelligent control, and diversified resource utilization.

[0005] The first aspect of the present invention provides a system for treating the oversize material of aged waste screens, comprising: a pretreatment unit, a multi-stage screening and sorting unit, a collaborative control unit, and a resource utilization unit;

[0006] The pretreatment unit is used to crush the aged waste to be processed to generate crushed material;

[0007] The multi-stage screening and sorting unit is connected to the pretreatment unit and includes multiple screening devices and multiple air separation devices arranged sequentially along the material conveying direction. It is used to sequentially perform multi-stage particle size screening and gravity separation on the crushed material to obtain multiple types of sorted materials.

[0008] The collaborative control unit is connected to the preprocessing unit and the multi-stage screening and sorting unit, and includes an image acquisition device and a control device. The image acquisition device is used to acquire real-time images of the material during the screening process. The control device is used to identify the blockage status and flow status of the material based on the real-time images, and outputs a collaborative adjustment control signal to the multi-stage screening and sorting unit when the identification result is greater than a preset threshold.

[0009] The resource utilization unit is connected to the multi-stage screening and sorting unit and is used to convert the corresponding sorted materials into recycled products according to a preset conversion path.

[0010] Optionally, the plurality of screening devices include a large screen, a magnetic separator, a primary drum screen, a secondary drum screen, and a star screen connected in sequence along the material conveying direction; the plurality of air separation devices include a primary air separator, a secondary air separator, and a tertiary air separator.

[0011] The feed inlet of the large-part screen is connected to the pretreatment unit, its upper discharge outlet is connected to the large inert material collection area, and its lower discharge outlet is connected to the feed inlet of the magnetic separator.

[0012] The material outlet of the magnetic separator is connected to the inlet of the primary drum screen, and its metal outlet is connected to the metal collection area.

[0013] The discharge port of the primary drum screen is connected to the inlet of the primary air classifier, and its discharge port is connected to the inlet of the secondary drum screen.

[0014] The discharge port of the secondary drum screen is connected to the inlet of the secondary air separator, and its discharge port is connected to the inlet of the star disk screen.

[0015] The upper discharge port of the star disk screen is connected to the inlet of the three-stage air separator, and its lower discharge port is connected to the humus collection area.

[0016] The light material outlets of the primary, secondary, and tertiary air separators are connected to the light combustible material collection area, and the heavy material outlets are connected to the heavy material collection area.

[0017] Optionally, the control device performs the following steps:

[0018] Based on the real-time images acquired by the image acquisition device, the blockage status characteristics and flow status characteristics of the material during the screening process are identified and extracted.

[0019] When the blockage state characteristic is greater than the blockage threshold, a first adjustment command is generated to reduce the operating frequency of the corresponding screening equipment, and a second adjustment command is generated simultaneously to increase the air volume of the corresponding air separation equipment.

[0020] When the flow rate characteristic is greater than the flow rate threshold, a third adjustment command is generated to reduce the conveying speed of the material from the pretreatment unit to the multi-stage screening and sorting unit.

[0021] Record and store the operating parameters and corresponding screening product output rate for each adjustment, and count the number of adjustments per unit time.

[0022] When the number of adjustments exceeds a preset threshold, the congestion threshold and the flow threshold are adjusted based on the output rate data.

[0023] Optionally, the step of identifying and extracting the blockage state characteristics and flow state characteristics of the material during the screening process based on the real-time images acquired by the image acquisition device includes:

[0024] The real-time image acquired by the image acquisition device is converted to grayscale, and an edge detection algorithm is used to extract the edge contour of the sieve hole area to generate a sieve hole area mask.

[0025] The real-time image is converted to a color space, and the material area is segmented according to the color difference threshold between the material and the screen to generate a material area mask;

[0026] The material area mask and the sieve hole area mask are superimposed at the pixel level. The proportion of the number of pixels in the material area covering the sieve hole area to the total number of pixels in the sieve hole area is calculated to generate the blockage area ratio. The blockage area ratio is used as the blockage state feature.

[0027] The pixel displacement of the material region in multiple consecutive real-time images is tracked, the average moving speed of the material per unit time is calculated, and the material throughput per unit time is estimated by combining the area of ​​the material region to generate instantaneous flow status features.

[0028] Time-series analysis is performed on multiple consecutive frames of images within a preset time window to extract the changing trends of material area and material movement speed. Based on these changing trends, the material flow rate at a future preset time point is predicted, and flow trend characteristics are generated.

[0029] The instantaneous flow state feature and the flow trend feature are used together as the flow state feature.

[0030] Optionally, the step of adjusting the congestion threshold and the flow threshold based on the output rate data when the number of adjustments exceeds a preset threshold includes:

[0031] Record the output rate of the screened product within a preset time period after each adjustment command is executed, and establish a data sequence of the output rate changing over time;

[0032] Calculate the average value of the data sequence within the statistical period, and subtract the average value from the preset target output rate to obtain the output rate deviation value;

[0033] When the number of adjustments exceeds a preset threshold and the absolute value of the output deviation is greater than a preset allowable deviation, the positive or negative direction of the output deviation is determined.

[0034] If the output deviation value is negative and the number of adjustments is greater than the preset number threshold, then the blockage threshold and the flow threshold are increased by a first preset step size, and the original blockage threshold and flow threshold are replaced.

[0035] If the output deviation value is negative and the number of adjustments is less than or equal to the preset number threshold, then the blockage threshold and the flow threshold are reduced by a second preset step size, and the original blockage threshold and flow threshold are replaced.

[0036] If the output deviation is positive, the current congestion threshold and flow threshold remain unchanged.

[0037] Optionally, the resource utilization unit includes a lightweight combustible material treatment subunit, a humus soil treatment subunit, an inert material treatment subunit, and a high-value plastic recycling subunit;

[0038] A high-value plastic recycling subunit is located before the light combustible material processing subunit and is used to separate high-value plastics from the light combustible material in the sorting material and prepare them into recycled plastic pellets.

[0039] The light combustible material processing subunit is used to prepare the light combustible material in the sorted material into waste-derived fuel;

[0040] The humus treatment subunit is used to convert humus samples from the sorted materials into biologically processed organic matrix.

[0041] An inert material processing subunit is used to prepare recycled aggregate from the heavy materials and large inert materials in the sorted materials.

[0042] Optionally, the high-value plastic recycling subunit includes:

[0043] A photoelectric sorting device is installed before the light combustible material processing subunit to separate high-value-added plastics from the light combustible material in the sorting material;

[0044] A cleaning device is used to clean the high-value-added plastic to produce cleaned high-value-added plastic.

[0045] The melt granulation device is used to melt and granulate the cleaned high-value-added plastic according to a preset melting temperature range to obtain recycled plastic granules.

[0046] Optionally, the humus treatment subunit performs the following steps:

[0047] Obtain a humus sample from the sorted material and test the organic matter content of the humus sample;

[0048] Determine whether the organic matter content is greater than or equal to a preset organic matter threshold;

[0049] If so, the humus sample is sent to an anaerobic digestion device and anaerobic digestion is carried out at a preset temperature and a preset volumetric load to produce biogas.

[0050] If not, the humus sample is mixed with the preset auxiliary materials, the mixture is adjusted to the preset carbon-nitrogen ratio range and the preset moisture content range, and aerobic composting is carried out by forced ventilation and turning, so as to convert the mixture into a decomposed organic matrix or soil conditioner.

[0051] Optionally, the inert matter handling subunit performs the following steps:

[0052] The heavy materials and large inert materials in the sorted materials are obtained and sent to the crushing device for crushing to generate crushed inert materials.

[0053] The crushed inert material is fed into a screening device for screening to obtain recycled aggregate that meets the preset particle size requirements.

[0054] The second aspect of this invention provides a method for treating the residue left on screens of aged waste, comprising:

[0055] The aged waste to be processed is crushed to generate crushed material;

[0056] The crushed material is subjected to multi-stage particle size screening and gravity separation in sequence to obtain multiple types of separated materials.

[0057] Real-time images of the material during the screening process are collected, and the blockage and flow status of the material are identified based on the real-time images. When the identification result is greater than a preset threshold, a control signal for coordinated adjustment is output.

[0058] According to the preset conversion path, the corresponding sorted materials are converted into recycled products.

[0059] As can be seen from the above technical solutions, the present invention has the following advantages:

[0060] This invention, through the integrated design of a pretreatment unit, a multi-stage screening and sorting unit, a collaborative control unit, and a resource utilization unit, achieves a systematic, end-to-end processing of oversize material from aged waste, offering significant advantages over existing technologies. The pretreatment unit crushes the aged waste, breaking down material agglomeration and generating crushed material suitable for subsequent screening. This lays the foundation for the efficient operation of the multi-stage screening and sorting unit, solving the screening difficulties caused by material agglomeration in traditional processing. The multi-stage screening and sorting unit connects to the pretreatment unit. Through multiple screening devices and multiple air separators arranged sequentially along the material conveying direction, it achieves multi-stage particle size screening and gravity separation of the crushed material. This accurately separates multiple types of materials, providing clearly categorized raw materials for subsequent conversion in the resource utilization unit. It overcomes the limitations of traditional single-screening modes, improves the comprehensiveness and accuracy of material separation, and creates conditions for the full-component resource utilization.

[0061] The collaborative control unit is connected to the pretreatment unit and the multi-stage screening and sorting unit. It acquires real-time images of the material during the screening process via an image acquisition device. The control device identifies the blockage and flow status of the material based on these images. When the identification results exceed a preset threshold, it outputs a collaborative adjustment control signal, effectively preventing equipment blockage and abnormal flow. This ensures stable collaborative operation of the pretreatment unit and the multi-stage screening and sorting unit, reduces manual intervention costs, and improves system reliability. The resource utilization unit is connected to the multi-stage screening and sorting unit. Following a preset conversion path, it converts various types of sorted materials obtained from the multi-stage screening and sorting unit into recycled products, realizing the resource utilization of oversize material from aged waste. This approach differs from the wasteful and polluting model of traditional waste treatment, fully exploring the value of the material. Simultaneously, it forms a complete processing loop with the other three units, ensuring that each unit's functions are complementary and synergistic, achieving efficient and orderly processing of oversize material from aged waste. This demonstrates significant practicality and innovation. Attached Figure Description

[0062] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0063] Figure 1 This is a structural block diagram of a system for treating waste screen residue from aged garbage, provided in an embodiment of the present invention.

[0064] Figure 2 This is a schematic diagram of the process flow of a system for treating screened waste from aged garbage, provided in an embodiment of the present invention.

[0065] Figure 3 A structural block diagram of the various units in a system for treating waste screen residue provided in an embodiment of the present invention;

[0066] Figure 4 This is a comparison chart of the furnace temperatures of the test furnace and the control furnace under different operating conditions provided in this embodiment of the invention;

[0067] Figure 5 This is a comparison chart of the evaporation rates of the experimental furnace and the control furnace under different operating conditions provided in this embodiment of the invention.

[0068] Figure 6 The flowchart illustrates the steps of a method for treating screened material from aged waste, as provided in an embodiment of the present invention. Detailed Implementation

[0069] This invention provides a system and method for treating screen residue from aged waste, particularly suitable for the resource recovery of highly viscous screen residue from aged waste with a moisture content of over 39% and complex composition. It addresses the technical problem that existing technologies for treating screen residue from aged waste lack a comprehensive systemic approach that integrates efficient sorting, intelligent control, and diversified resource utilization.

[0070] Specifically, this invention constructs a comprehensive processing system integrating a pretreatment unit, a multi-stage screening and sorting unit, a collaborative control unit, and a resource utilization unit. These units are not simply superimposed on existing technologies, but rather adaptively combined to address the high moisture content, high viscosity, and complex composition of aged waste, forming a collaborative system encompassing "process-equipment-control-utilization" to achieve a synergistic effect greater than the sum of its parts. This enables efficient separation and high-value utilization of the oversize material from aged waste, along with full-component utilization. Simultaneously, the intelligent control function of the collaborative control unit enables unmanned and stable operation of the production line, ultimately maximizing environmental, economic, and social benefits.

[0071] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. It should be noted that in the optional embodiments of the present invention, the object information and other related data involved require the permission or consent of the object when the embodiments of the present invention are applied to specific products or technologies, and the collection, use, and processing of related data must comply with the relevant laws, regulations, and standards of the relevant countries and regions. That is to say, if the embodiments of the present invention involve data related to the object, it needs to be obtained with the authorization and consent of the object, the authorization and consent of the relevant departments, and in compliance with the relevant laws, regulations, and standards of the country and region. If personal information is involved in the embodiments, the acquisition of all personal information requires the consent of the individual. If sensitive information is involved, the separate consent of the information subject is required, and the embodiments also need to be implemented with the authorization and consent of the object.

[0072] Example 1

[0073] Please see Figure 1 , Figure 1 This is a structural block diagram of a system for treating waste screen residue from aged garbage, provided in an embodiment of the present invention.

[0074] The present invention provides a system for treating the oversize material from aged waste screens, comprising: a pretreatment unit, a multi-stage screening and sorting unit, a collaborative control unit, and a resource utilization unit.

[0075] The pretreatment unit is used to crush the aged waste to be processed, generating crushed material.

[0076] Furthermore, the pretreatment unit can employ a low-speed, high-torque twin-shaft shear crusher. Specifically, the twin-shaft shear crusher includes a low-speed, high-torque drive system, two relatively rotating cutter shafts, a main shaft, moving cutters, anti-winding fixed cutters, a multi-combination sealing structure, and an overload automatic reverse control system. The low-speed, high-torque drive system is connected to the main shaft and drives its operation. The moving cutters are made of high-wear-resistant alloy steel and are arranged in a staggered spiral pattern on the surface of the main shaft, with the moving cutters fixedly connected to the cutter shafts. The anti-winding fixed cutters are fixedly installed on both sides of the cutter shafts, simultaneously shearing and cleaning any entangled materials adhering to the cutter shafts, preventing operational malfunctions caused by the entanglement of fabrics or films. The multi-combination sealing structure is installed at the bearing location of the twin-shaft shear crusher, forming multiple protective barriers to prevent dust, wastewater, and material debris from entering the bearing cavity, ensuring stable bearing operation and extending equipment life. The overload automatic reversal control system is connected to the main shaft and the collaborative control unit. It is used to detect the load on the main shaft and control the cutter shaft to reverse and release stuck materials when the main shaft is overloaded. At the same time, it can transmit the operating status, load data and adjustment actions to the collaborative control unit in a synchronized manner to achieve coordinated control with the subsequent multi-stage screening and sorting units.

[0077] In this embodiment of the invention, the pretreatment unit is a dual-shaft shear crusher. This equipment is specifically designed for the material characteristics of aged waste, which is prone to entanglement and agglomeration. Unlike traditional high-speed impact crushers, the discharge port of the equipment is connected to the feed port of the multi-stage screening and sorting unit via a chain conveyor. Its core components include a low-speed, high-torque drive system, two relatively rotating cutter shafts, a main shaft, and moving cutters. The low-speed, high-torque drive system is connected to the main shaft and is used to drive the main shaft to rotate. The moving cutters are made of high-wear-resistant alloy steel and are arranged in a staggered spiral pattern on the surface of the main shaft, and the moving cutters are fixedly connected to the cutter shafts. The equipment is designed for low speed and high torque, typically suitable for operating conditions of 15-25 rpm. Combined with moving cutters made of high-wear-resistant alloy steel, it has excellent impact resistance and anti-entanglement performance, and can stably adapt to the crushing requirements of complex components of aged waste. During operation, the equipment uses a low-speed, high-torque drive system to rotate the main shaft, which in turn drives two opposing rotating cutter shafts. The staggered moving blades on these shafts shear, tear, and compress the aged waste entering the equipment. This effectively handles easily entangled materials such as fabrics and plastic films commonly found in aged waste, breaking up clumps and brittle materials, and crushing large materials to a suitable particle size range for subsequent screening, typically within 300mm. This process avoids the problems of high dust levels and material entanglement / clogging that often occur with traditional high-speed impact crushers. After crushing, the material's agglomeration is broken, its dispersion is improved, and its volume is uniformly reduced, creating favorable conditions for subsequent precise screening and increasing screening efficiency by approximately 20-30%.

[0078] The multi-stage screening and sorting unit, connected to the pretreatment unit, includes multiple screening devices and multiple air separation devices arranged sequentially along the material conveying direction, used to sequentially perform multi-stage particle size screening and gravity separation on crushed materials to obtain multiple types of sorted materials.

[0079] In this embodiment of the invention, a multi-stage screening and sorting unit is connected to a pretreatment unit, including multiple screening devices and multiple air-separating devices arranged sequentially along the material conveying direction. Its core function is to sequentially perform multi-stage particle size screening and gravity separation on the crushed material output from the pretreatment unit, obtaining multiple types of sorted materials. This provides a precise material basis for the diversified resource utilization of the subsequent resource utilization unit. This unit adopts a multi-stage screening + multi-stage air-separation linkage adaptation process to perform step-by-step, refined separation of aged waste components with different particle sizes and densities. Simultaneously, a star-shaped screen is introduced to solve the clogging problem in the screening process of high-moisture, sticky fine materials. The particle size grading range of each screening device is precisely matched with the operating air volume of the corresponding air-separating device, ensuring the separation efficiency and material separation purity throughout the entire process.

[0080] Furthermore, the multiple screening devices include a large screen, a magnetic separator, a primary drum screen, a secondary drum screen, and a star-shaped screen connected in sequence along the material conveying direction; the multiple air separation devices include a primary air separator, a secondary air separator, and a tertiary air separator;

[0081] The feed inlet of the large-sized screen is connected to the pretreatment unit, its upper discharge outlet is connected to the large inert material collection area, and its lower discharge outlet is connected to the feed inlet of the magnetic separator.

[0082] The material outlet of the magnetic separator is connected to the inlet of the primary drum screen, and its metal outlet is connected to the metal collection area.

[0083] The discharge port of the primary rotary drum screen is connected to the inlet of the primary air classifier, and its discharge port is connected to the inlet of the secondary rotary drum screen.

[0084] The discharge port of the secondary drum screen is connected to the inlet of the secondary air separator, and its discharge port is connected to the inlet of the star disk screen.

[0085] The upper discharge port of the star disk screen is connected to the inlet of the three-stage air separator, and its lower discharge port is connected to the humus collection area.

[0086] The light material outlets of the primary, secondary, and tertiary air separators are connected to the light combustible material collection area, while the heavy material outlets are connected to the heavy material collection area.

[0087] In embodiments of the present invention, such as Figure 2 and Figure 3As shown, the core screening equipment in the multi-stage screening and sorting unit includes a large screen, a magnetic separator, a primary drum screen, a secondary drum screen, and a star-shaped screen connected sequentially along the material conveying direction. The core air separation equipment includes a primary air separator, a secondary air separator, and a tertiary air separator. The connection relationships, operating parameters, and working principles of each piece of equipment are as follows:

[0088] I. Multiple screening devices (particle size classification and magnetic separation type)

[0089] This group of equipment is the front-end grading process of the unit, arranged in series along the material conveying direction. Its core function is to grade materials according to particle size step by step, simultaneously separating ferromagnetic metals, and providing uniformly sized material for the downstream air separation process. It includes a large screen, a magnetic separator, a primary drum screen, a secondary drum screen, and a star disk screen. The connection relationship, operating parameters, and working principle of each piece of equipment are as follows:

[0090] 1. Large component screening (first-level large component separation process)

[0091] The equipment's inlet is connected to the outlet of the twin-shaft shear crusher in the pretreatment unit via a chain conveyor. The oversize outlet is connected to the large inert material collection area, and the undersize outlet is connected to the inlet of the magnetic separator. The equipment can be a bar screen or a large-aperture drum screen, with an aperture of ≥200mm and a fixed operating frequency of 50Hz. The core function of this process is to separate large bricks, concrete blocks, and other inert construction waste from the crushed material. Large inert materials oversize are directly conveyed to the large inert material collection area for subsequent recycling into building materials; undersize materials with a particle size <200mm are conveyed to the magnetic separator for further processing.

[0092] 2. Magnetic separator (for separating ferromagnetic metals)

[0093] The equipment's inlet connects to the undersize outlet of the large-format screen, the material outlet connects to the inlet of the primary drum screen, and the metal outlet connects to the metal collection area. The equipment uses a suspended permanent magnet separator or electromagnetic separator with a maximum magnetic attraction of 20 kg. The optimal operating condition for the conveyor belt speed is 2.0 m / s. The core function of this process is to efficiently recover ferromagnetic metals such as iron nails and wires from the material after primary screening. The separated ferromagnetic metals are transported to the metal collection area through the metal outlet and can be sold directly as recycled resources. The iron-removed material is transported to the primary drum screen through the material outlet for further particle size classification.

[0094] 3. Secondary particle size classification subsystem (primary drum screen, secondary drum screen, star disk screen)

[0095] This subsystem adopts a combination design of multi-stage drum screen and star disk screen. Adaptive equipment is selected based on the characteristics of materials with different particle sizes to avoid clogging problems with single equipment. The operating frequency of each device can be dynamically adjusted according to the material characteristics, with an optimal range of 15-30Hz. The connection relationships and operating parameters of each device are as follows:

[0096] (1) Primary drum screen: The feed inlet is connected to the material outlet of the magnetic separator, the oversize outlet is connected to the feed inlet of the primary air separator, and the undersize outlet is connected to the feed inlet of the secondary drum screen. The screen aperture is set to 100mm, and the operating frequency is optimally between 25-30Hz. Its core function is to separate the magnetically separated material into two parts with a particle size ≥100mm and <100mm. The oversize material is conveyed to the primary air separator, and the undersize material is conveyed to the secondary drum screen.

[0097] (2) Secondary drum screen: The feed inlet is connected to the undersize discharge outlet of the primary drum screen, the oversize discharge outlet is connected to the feed inlet of the secondary air separator, and the undersize discharge outlet is connected to the feed inlet of the star disk screen. The screen aperture is set to 40mm, and the operating frequency is optimally between 20-25Hz. Its core function is to separate the incoming material into two parts with a particle size ≥40mm and <40mm. The oversize material is conveyed to the secondary air separator, and the undersize material is conveyed to the star disk screen.

[0098] (3) Star-shaped disk screen: This type of screen is specially designed to address the pain points of screening high-moisture and high-viscosity humus materials. The inlet is connected to the undersize outlet of the secondary drum screen, the oversize outlet is connected to the inlet of the tertiary air classifier, and the undersize outlet is connected to the humus collection area. The screen diameter is set to 15-20mm, and the optimal operating frequency is 15-20Hz. This equipment uses the rotation of the star-shaped disk to move and transport materials. It has excellent anti-clogging performance for high-moisture and high-viscosity humus and can effectively separate fine humus materials with a particle size <20mm. The undersize humus is directly transported to the humus collection area and enters the subsequent organic matrix preparation path; the oversize material is transported to the tertiary air classifier.

[0099] II. Multiple air separation devices (gravity separation type)

[0100] This group of equipment is the back-end sorting process of the unit, corresponding and interconnected with the front-end multi-stage screening equipment. Its core function is to separate light and heavy materials based on their density for oversize materials in different particle size ranges. It includes a primary air separator, a secondary air separator, and a tertiary air separator. The connection relationships, operating parameters, and working principles of each piece of equipment are as follows:

[0101] The maximum air volume of each air separator in this system can reach 24,000 m³ / h, and the optimal operating frequency is 20-30 Hz. The air volume and speed can be adjusted according to the particle size and density characteristics of the corresponding screening material. The core technology principle is to use airflow to make materials of different densities generate different movement trajectories in the settling chamber, thereby achieving efficient separation of light combustibles and heavy inert materials.

[0102] (1) Primary air classifier: The feed inlet is connected to the discharge outlet of the primary drum screen, and it is used for air separation of materials with a particle size ≥ 100 mm.

[0103] (2) Secondary air classifier: The feed inlet is connected to the discharge outlet of the secondary drum screen, and it is used for air separation of materials with a particle size ≥40mm and <100mm.

[0104] (3) Three-stage air classifier: The feed inlet is connected to the discharge outlet of the star disk screen, and it is used for air separation of materials with a particle size ≥20mm and <40mm.

[0105] The light-weight discharge ports of the aforementioned primary, secondary, and tertiary air separators are all connected to the light-weight combustible material collection area. The separated light-weight materials, after being collected together, can achieve a purity of over 90%, mainly consisting of high-calorific-value combustible materials such as plastics, paper, and textiles, which can be used in subsequent waste-derived fuel preparation pathways. The heavy-weight discharge ports of each air separator are all connected to the heavy-weight material collection area. The separated heavy-weight materials are mainly inert materials such as bricks, tiles, glass, and ceramic fragments, which can be used in subsequent recycled aggregate preparation pathways.

[0106] The multi-stage screening and sorting unit strictly follows the process route of screening and grading first, followed by air separation. The oversize material from each stage of particle size screening is connected to a dedicated air separation device, achieving one-to-one matching of particle size grading and specific gravity separation. This avoids the problems of low separation efficiency and insufficient purity caused by air separation of materials of different particle sizes. At the same time, the operating status of all equipment in the unit can be linked with the collaborative control unit to achieve dynamic adjustment of operating parameters. Through the linkage and matching of multi-stage screening and multi-stage air separation, the unit achieves the fine separation of all components, including inert materials, ferromagnetic metals, humus, and high-calorific-value combustibles, from the oversize material of aged waste. This solves the industry pain points of traditional processes, such as easy clogging of high-moisture fine materials, low purity of light and heavy materials, and insufficient sorting efficiency. It provides a stable material foundation for the diversified resource utilization of subsequent resource utilization units and makes up for the shortcomings of existing technologies that lack systematic and comprehensive treatment capabilities.

[0107] The collaborative control unit is connected to the preprocessing unit and the multi-stage screening and sorting unit, and includes an image acquisition device and a control device. The image acquisition device is used to acquire real-time images of the material during the screening process. The control device is used to identify the blockage status and flow status of the material based on the real-time images, and outputs a collaborative adjustment control signal to the multi-stage screening and sorting unit when the identification result is greater than a preset threshold.

[0108] In embodiments of the present invention, such as Figure 2 and Figure 3 As shown, the collaborative control unit is connected to the preprocessing unit and the multi-stage screening and sorting unit, respectively. Its main components include an image acquisition device and a control device (i.e.,...). Figure 2 The system utilizes a PLC-based intelligent control system. The image acquisition device consists of high-definition industrial cameras deployed at easily clogged points in the pre-processing unit (crusher), multi-stage screening and sorting units (drum screens, star screens, and material conveyor belts). Its main function is to acquire real-time images of the material during the screening process. The control device is a PLC central control cabinet with a PLC programmable logic controller as the central control unit. It integrates a frequency converter, data storage module, and supporting image recognition algorithms to form a closed-loop intelligent control system. Its main function is to identify the blockage and flow status of the material based on real-time images. When the identification result exceeds a preset threshold, it outputs coordinated adjustment control signals to the multi-stage screening and sorting units, achieving fully automated control of the entire process, including real-time monitoring, intelligent analysis, automatic parameter adjustment, and data self-optimization.

[0109] Further, the control device performs the following steps:

[0110] S11. Based on real-time images acquired by the image acquisition device, identify and extract the blockage status characteristics and flow status characteristics of the material during the screening process.

[0111] Further, step S11 includes the following steps:

[0112] S111. The real-time image acquired by the image acquisition device is converted to grayscale, and the edge detection algorithm is used to extract the edge contour of the sieve hole area to generate a sieve hole area mask.

[0113] S112. Perform color space conversion on the real-time image, segment the material area according to the color difference threshold between the material and the screen, and generate a material area mask.

[0114] S113. Superimpose the material area mask and the sieve hole area mask at the pixel level, calculate the proportion of the number of pixels in the material area covering the sieve hole area to the total number of pixels in the sieve hole area, generate the blockage area ratio, and use the blockage area ratio as the blockage status feature.

[0115] S114. Track the pixel displacement of the material area in multiple consecutive real-time images, calculate the average moving speed of the material per unit time, estimate the material throughput per unit time by combining the area of ​​the material area, and generate instantaneous flow status features.

[0116] S115. Perform time-series analysis on multiple consecutive frames of images within a preset time window to extract the changing trends of material area and material movement speed, predict material flow rate at future preset time points based on the changing trends, and generate flow trend features.

[0117] S116. Instantaneous flow state characteristics and flow trend characteristics are used together as flow state characteristics.

[0118] In this embodiment of the invention, the real-time image acquired by the image acquisition device is converted to grayscale to reduce image computation while highlighting the contour differences between the sieve holes and the sieve mesh. Then, the Canny edge detection algorithm, commonly used in the field, is employed to extract the edge contours of the sieve hole area, generating a sieve hole area mask. This mask is a conventional processing method in the field of industrial image recognition used to delineate the target recognition area and shield interference from non-target areas. The sieve hole area mask only retains the effective sieve hole area of ​​the screening equipment, completely shielding interference from irrelevant content such as the equipment frame and surrounding environment, ensuring the accuracy of subsequent blockage identification. The real-time image undergoes color space conversion, transforming the conventional RGB image into the HSV color space, which is more suitable for color segmentation. The material area is segmented based on the color difference threshold between the material and the sieve mesh, generating a material area mask. This color difference threshold is a pre-defined color differentiation threshold value based on the material color of the sieve mesh and the conventional color range of the aged waste material to be processed. This threshold can stably distinguish the sieve body from the material covering the sieve mesh, accurately delineating the area covered by the material.

[0119] The material area mask and the screen aperture area mask are superimposed pixel-wise. The proportion of pixels in the screen aperture area covered by the material area is calculated to represent the total number of pixels in the screen aperture area. This proportion is then used as a clogging status feature. This feature value can intuitively and quantitatively reflect the degree of screen clogging. For example, when the total number of pixels in the screen aperture area is 10,000 and the number of pixels in the screen aperture area covered by the material is 1,000, the clogging area proportion is 10%, meaning the clogging status feature value is 10%.

[0120] The pixel displacement of the material region in multiple consecutive real-time images is tracked. Using a commonly used optical flow target tracking algorithm, the average moving speed of the material per unit time is calculated. Combined with the area of ​​the material region, the material throughput per unit time is estimated, generating an instantaneous flow rate characteristic. This characteristic value can reflect the instantaneous material conveying volume on the conveyor belt and within the screening equipment in real time, providing real-time data support for the judgment and adjustment of flow overload.

[0121] A time-series analysis is performed on multiple consecutive frames of images within a preset time window to extract the changing trends of the material area and material movement speed. Based on these trends, the material flow rate at a future preset time point is predicted, generating flow trend features. The preset time window is a time-series analysis duration pre-set based on the production line conveyor speed and material handling cycle time, typically set to 5-30 seconds, fully covering the entire process from material conveying to the screening equipment. The future preset time point is a prediction node pre-set based on the production line operating conditions, typically set to 3-10 seconds later, allowing for early prediction of the risk of sudden increases in material flow rate and enabling proactive prevention. The aforementioned instantaneous flow state features and flow trend features are combined as the flow state features, covering both the current real-time material throughput and the flow change trend in the short term. This approach can simultaneously address both instantaneous flow overload and continuous flow growth, significantly improving the comprehensiveness and accuracy of flow rate assessment.

[0122] S12. When the blockage status characteristics are greater than the blockage threshold, a first adjustment command is generated to reduce the operating frequency of the corresponding screening equipment, and a second adjustment command is generated simultaneously to increase the air volume of the corresponding air classifier.

[0123] In this embodiment of the invention, the clogging threshold is a critical value of the clogging area percentage preset according to the design parameters of the screening equipment and the material screening efficiency requirements, which can typically be set to 10%. The first and second adjustment commands are both transmitted to the frequency converters of the corresponding equipment via the PLC central control cabinet for execution. The vibration frequency adjustment range of the screening equipment is 0-50Hz, and the air volume adjustment range of the air separator is 0-24000m³ / h. The conventional engineering implementation logic is as follows: when the clogging area of ​​the screen holes reaches 10% and exceeds the clogging threshold, the PLC central control cabinet automatically reduces the operating frequency of the corresponding screening machine by 10Hz, while simultaneously increasing the air volume of the matching air separator by 20%. By reducing the screening machine speed, material accumulation is reduced, and by increasing the air volume of the air separator, lightweight materials adhering to the screen surface are removed, thus achieving rapid unblocking of the clogging.

[0124] S13. When the flow rate characteristics are greater than the flow rate threshold, a third adjustment command is generated to reduce the conveying speed of the material from the pretreatment unit to the multi-stage screening and sorting unit.

[0125] In this embodiment of the invention, when the flow rate characteristic exceeds the flow rate threshold, a third adjustment command is generated to reduce the conveying speed of the material from the pretreatment unit to the multi-stage screening and sorting unit. Here, the flow rate threshold is a pre-set critical value for material flow based on the rated processing capacity of the production line and the maximum feed load of the screening equipment; conventionally, it can be set to 130% of the rated instantaneous processing capacity of the production line. The third adjustment command is transmitted to the frequency converter of the front-end chain conveyor via the PLC central control cabinet for execution. By reducing the conveyor speed, the amount of material entering the screening unit is reduced, material accumulation is alleviated, and blockages and equipment overload failures are prevented from the source.

[0126] S14. Record and store the operating parameters and corresponding screening product yield for each adjustment, and count the number of adjustments per unit time.

[0127] In this embodiment of the invention, the equipment operating parameters and corresponding screening product yield are recorded and stored for each adjustment, and the number of adjustments per unit time is statistically analyzed. The equipment operating parameters include the operating frequency of the screening equipment before and after adjustment, the air volume of the air classifier, and the conveying speed of the conveyor. The screening product yield refers to the proportion of the mass of qualified particle size material output by the corresponding screening equipment per unit time to the total mass of the feed. The unit time is a pre-set statistical duration based on the production line operating conditions, typically set to 1 hour, which objectively reflects the system's adjustment frequency and operational stability.

[0128] S15. When the number of adjustments exceeds the preset threshold, adjust the blockage threshold and flow threshold based on the output rate data.

[0129] Further, step S15 includes the following steps:

[0130] S151. Record the output rate of the screened product within a preset time period after each adjustment command is executed, and establish a data sequence of the output rate changing over time.

[0131] S152. Calculate the average value of the data sequence within the statistical period, and subtract the average value from the preset target output rate to obtain the output rate deviation value.

[0132] S153. When the number of adjustments exceeds the preset threshold and the absolute value of the output deviation is greater than the preset allowable deviation, determine the positive or negative direction of the output deviation.

[0133] S154. If the output deviation value is negative and the number of adjustments is greater than the preset number of thresholds, then the blockage threshold and flow threshold will be increased by the first preset step size respectively, and the original blockage threshold and flow threshold will be replaced.

[0134] S155. If the output deviation value is negative and the number of adjustments is less than or equal to the preset number threshold, then the blockage threshold and flow threshold are reduced by the second preset step size respectively, and the original blockage threshold and flow threshold are replaced.

[0135] S156. If the output deviation value is positive, then keep the current congestion threshold and flow threshold unchanged.

[0136] In this embodiment of the invention, the output rate of the screened product within a preset time period after each adjustment command is executed is recorded, establishing a data sequence of output rate changes over time. The preset time period is a pre-set effect evaluation duration based on the response speed of the screening equipment and the material conveying cycle time. It is typically set to 30-60 seconds after the adjustment command is executed, fully covering the entire process from the adjustment action taking effect to the stabilization of the screening state, ensuring that the collected output rate data accurately reflects the actual effect of the adjustment action. The average value of the aforementioned output rate data sequence within the statistical period is calculated, and this average value is subtracted from the preset target output rate to obtain the output rate deviation value. The statistical period here is consistent with the unit time in step S14, typically 1 hour. The preset target output rate is a qualified output rate target value pre-set according to the production line design standards and screening process requirements, serving as a key benchmark for measuring whether the screening effect meets the standards.

[0137] When the number of adjustments exceeds a preset threshold and the absolute value of the output deviation exceeds a preset allowable deviation, the direction of the output deviation is determined. The preset threshold is the maximum allowable number of adjustments per unit time, pre-set based on the requirements for stable production line operation. It is typically set to 5 times / hour. If the number of adjustments per unit time exceeds this value, it indicates that the existing threshold does not match the actual operating conditions, the system frequently triggers adjustments, and operational stability is insufficient. The preset allowable deviation is the maximum allowable deviation range of the output rate, pre-set based on the screening process requirements. It is typically set to ±5%. If the output deviation exceeds this range, it indicates that the screening effect under the existing control strategy has not met the design target, and the threshold needs to be optimized and adjusted.

[0138] If the output deviation is negative, meaning the actual output is lower than the preset target output and the number of adjustments exceeds the preset threshold, then the blockage threshold and flow threshold are increased by a first preset step size, replacing the original blockage threshold and flow threshold. Here, the first preset step size is a pre-set single-adjustment range based on the threshold adjustment accuracy requirements. For the blockage threshold, it can typically be set to 2% of the blockage area percentage; for the flow threshold, it can typically be set to 10% of the rated processing capacity percentage. By slightly increasing the thresholds, ineffective and frequent adjustments to the system are reduced, improving operational stability and gradually optimizing the screening output.

[0139] If the output deviation is negative and the number of adjustments is less than or equal to the preset threshold, the blockage threshold and flow threshold are reduced by a second preset step size, replacing the original blockage threshold and flow threshold. The second preset step size is a pre-set adjustment range based on the threshold adjustment accuracy requirements. For the blockage threshold, it can typically be set to 1% of the blockage area percentage; for the flow threshold, it can typically be set to 5% of the rated processing capacity percentage. By slightly lowering the thresholds, the system's sensitivity to blockage and flow overload is improved, triggering adjustments earlier and increasing the screening output. If the output deviation is positive, meaning the actual output is higher than or equal to the preset target output, the current blockage threshold and flow threshold remain unchanged to ensure stable system operation and consistently satisfactory screening results.

[0140] The resource utilization unit, connected to the multi-stage screening and sorting unit, is used to convert the corresponding sorted materials into recycled products according to a preset conversion path.

[0141] In this embodiment of the invention, the resource utilization unit is the final step in maximizing the value of the oversize material. Based on the characteristics of the different sorted materials, four parallel high-value resource utilization paths are designed. Each path has clearly defined process parameters and quantifiable effects, achieving full-component, high-value resource utilization and overcoming the limitations of traditional single-utilization models. Specifically, the resource utilization unit includes a lightweight combustible material treatment subunit, a humus treatment subunit, an inert material treatment subunit, and a high-value plastic recycling subunit. Each subunit is connected to the corresponding discharge area of ​​the multi-stage screening and sorting unit. Appropriate processing technologies are adopted for different types of sorted materials to prepare high-value-added recycled products such as waste-derived fuel, organic matrix, recycled aggregate, and recycled plastic pellets.

[0142] Furthermore, a high-value plastic recycling subunit is located before the light combustible material processing subunit, and is used to separate high-value-added plastics from the light combustible materials in the sorting materials and prepare them into recycled plastic pellets.

[0143] Furthermore, the high-value plastic recycling sub-unit includes:

[0144] The photoelectric sorting device is installed before the light combustible material processing subunit to separate high value-added plastics from the light combustible material in the sorting material;

[0145] A cleaning device is used to clean high-value-added plastics to produce cleaned high-value-added plastics.

[0146] The melt granulation device is used to melt and granulate cleaned high-value-added plastics according to a preset melting temperature range to obtain recycled plastic granules.

[0147] In this embodiment of the invention, the high-value plastic recycling subunit is located before the light combustible material processing subunit. Its input end is connected to the light combustible material collection area of ​​the multi-stage screening and sorting unit, and its output end is divided into two paths: one path transports the sorted high-value-added plastics to downstream processes, and the other path transports the remaining light combustible material to the light combustible material processing subunit. Its main function is to separate high-value-added plastics from the light combustible material in the sorted materials and prepare them into recycled plastic granules, representing a utilization path with a high degree of resource utilization and economic value. This subunit mainly includes a photoelectric sorting device, a cleaning device, and a melt granulation device. The implementation methods of each device are as follows:

[0148] (1) Photoelectric sorting device: installed before the light combustible material processing subunit, its main function is to separate high-value-added plastics from the light combustible materials. The device can use near-infrared (NIR) sorting equipment, which can accurately identify and separate specific types of high-value plastics from light combustible materials, such as PET (Polyethylene Terephthalate) and HDPE (High Density Polyethylene), with a separation purity of over 95%.

[0149] (2) Cleaning device: Its main function is to clean the high value-added plastics that have been sorted out, remove impurities, oil stains and other pollutants attached to the surface of the material, and generate cleaned high value-added plastics to ensure the purity and quality of subsequent granulation products.

[0150] (3) Melt granulation device: Its main function is to process the cleaned high-value-added plastics into recycled plastic granules according to the corresponding preset melting temperature range for different types of plastics. The preset melting temperature range here is a temperature range pre-set according to the melting characteristics and processing performance of different types of plastics. The preset melting temperature range for PET plastic is 260-280℃, and the preset melting temperature range for HDPE plastic is 180-220℃. The purity of the recycled plastic granules finally produced can reach more than 92%, which can be sold as industrial raw materials to achieve higher economic returns.

[0151] The light combustible material processing subunit is used to prepare waste-derived fuel from the sorted materials.

[0152] In this embodiment of the invention, the input end of the lightweight combustible material processing subunit is connected to the residual material output end of the high-value plastic recycling subunit. Its main function is to prepare waste-derived fuel from the sorted materials. The sorted high-purity lightweight materials, including plastics, textiles, wood, and bamboo, are fed into the waste-derived fuel preparation system, where they undergo processes such as modifier addition, drying, and molding to produce high-quality waste-derived fuel. Limestone can be used as the modifier to fix sulfur and chlorine, reducing pollutant emissions during fuel combustion. The drying process reduces the material's moisture content to below 15%. The molding process compresses the material into blocks or rods. The final waste-derived fuel has a stable calorific value above 14.6 MJ / kg and an ash content of no more than 10%. It can be used as an alternative fuel for cement kiln co-processing, circulating fluidized bed boilers, or pyrolysis gasification. Compared to direct co-firing, it exhibits more stable combustion, easier control of secondary pollution, and higher economic and environmental value.

[0153] The humus treatment subunit is used to convert humus samples from sorted materials into biologically processed organic matrix.

[0154] Furthermore, the humus treatment subunit performs the following steps:

[0155] S21. Obtain humus samples from the sorted materials and test the organic matter content of the humus samples.

[0156] S22. Determine whether the organic matter content is greater than or equal to the preset organic matter threshold. If yes, proceed to step S23; otherwise, proceed to step S24.

[0157] S23. The humus sample is sent into the anaerobic digestion device and anaerobic digestion is carried out under preset temperature conditions and preset volumetric load to produce biogas.

[0158] S24. Mix the humus sample with the preset auxiliary materials, adjust the mixture to the preset carbon-nitrogen ratio range and preset moisture content range, and carry out aerobic composting by forced ventilation and turning, so as to transform the mixture into a decomposed organic matrix or soil conditioner.

[0159] In this embodiment of the invention, the input end of the humus treatment subunit is connected to the humus collection area of ​​the multi-stage screening and sorting unit. Its main function is to convert humus samples from the sorted materials into organic matrix through biological treatment. Before entering the biological treatment process, the humus samples must be tested for heavy metal content, including Cr, Pb, As, etc., and must meet the relevant standards such as the Technical Specification for Resource Utilization of Garden Greening Waste or Organic Fertilizer NY525-2021 before entering the subsequent treatment process to ensure the environmental compliance of the final product. This subunit matches the appropriate biological treatment process according to the organic matter content of the humus. The specific execution steps are as follows: Obtain humus samples from the sorted materials and test the organic matter content in the humus samples. The humus samples are materials with a particle size of less than 20mm that are screened through the star disk sieve of the multi-stage screening and sorting unit. The organic matter content is detected using the commonly used in-sector acineration method to provide quantitative data for the selection of subsequent process paths. Determine whether the detected organic matter content is greater than or equal to a preset organic matter threshold. The preset organic matter threshold here is a critical value pre-set based on the feed requirements of the anaerobic digestion process and the biodegradability of the humus soil, typically set at 30%, to differentiate the suitable biological treatment pathways for the humus soil. If the organic matter content is greater than or equal to the preset organic matter threshold, the humus soil sample is sent to the anaerobic digester for anaerobic digestion at a preset temperature and volumetric loading rate to produce biogas. The preset temperature conditions are temperature ranges pre-set based on the activity range of anaerobic microorganisms, divided into mesophilic and hyperthermic conditions. The optimal range for mesophilic conditions is 35-40℃, and for hyperthermic conditions, it is 55-60℃. The preset volumetric loading rate is the amount of volatile solids that can be processed per unit volume per day based on the design parameters of the anaerobic digester and the biodegradability of the material, with an optimal range of 2.0-3.0 kgVS / (m³・d). Through the decomposition of anaerobic microorganisms, the material produces biogas, which can contain more than 60% methane and can be used for power generation or heating. The digestate and sludge produced after digestion are rich in organic matter and nutrients and can be further processed and utilized. If the organic matter content is less than the preset organic matter threshold, the humus sample is mixed with preset additives to adjust the mixture to the preset carbon-nitrogen ratio and moisture content ranges. Aerobic composting is then carried out through forced ventilation and turning, transforming the mixture into a well-rotted organic matrix or soil conditioner. The preset additives are suitable materials pre-selected to adjust the physicochemical properties of the materials and meet the requirements of aerobic composting. Commonly used materials include garden waste, straw, and other agricultural and forestry waste, used to adjust the carbon-nitrogen ratio and looseness of the materials. The preset carbon-nitrogen ratio range is a pre-set range based on the growth and metabolic needs of aerobic composting microorganisms, with an optimal range of 25-35:1. The preset moisture content range is a pre-set range based on the activity requirements of aerobic microorganisms, with an optimal range of 50-60%.During the composting process, forced ventilation and regular turning provide sufficient oxygen for microbial activity. Under the action of microorganisms, the material is gradually transformed into a mature and stable organic matrix or soil conditioner, which can be used in landscaping, mine restoration and other scenarios.

[0160] The inert material processing subunit is used to prepare recycled aggregate from heavy materials and large inert materials in the sorted materials.

[0161] Furthermore, the inert matter handling subunit performs the following steps:

[0162] S31. Obtain heavy materials and large inert materials from the sorted materials and send them to the crushing device for crushing to generate crushed inert materials.

[0163] S32. The crushed inert material is fed into a screening device for screening to obtain recycled aggregate that meets the preset particle size requirements.

[0164] In this embodiment of the invention, the input end of the inert material treatment subunit is connected to the large inert material collection area and heavy material collection area of ​​the multi-stage screening and sorting unit. Its main function is to prepare recycled aggregate from the heavy and large inert materials in the sorted materials. Heavy materials include materials such as bricks, tiles, glass, and ceramics separated by air classification, while large inert materials include large pieces of construction waste separated by large-scale screening. The recycled aggregates of different particle sizes obtained through crushing and screening can be used to produce recycled permeable bricks, roadbed materials, recycled concrete, and other building materials. The compressive strength of the recycled permeable bricks prepared using the above-mentioned recycled aggregates can reach 35 MPa, meeting the relevant standards for municipal road construction in the "Code for Construction and Quality Acceptance of Urban Road Engineering" CJJ1-2008, thus realizing the resource-based recycling of inert waste.

[0165] This invention achieves systematic processing of oversize material from aged waste through a four-unit integrated design: a pretreatment unit, a multi-stage screening and sorting unit, a collaborative control unit, and a resource utilization unit. The pretreatment unit crushes the aged waste, laying the foundation for subsequent screening. The multi-stage screening and sorting unit, through the orderly connection and coordinated operation of large-scale screens, magnetic separators, multi-stage drum screens, star-plate screens, and a three-stage air separator, accurately separates various types of materials, including light combustibles, heavy inert materials, metals, and organic humus, effectively solving the problem of clogging in high-moisture fine material screening and improving sorting accuracy and efficiency. The resource utilization unit, through the division of labor and cooperation of the four sub-units, transforms various sorted materials into recycled plastic pellets, waste-derived fuels, organic matrix, and recycled aggregates, achieving full-component resource utilization of the materials.

[0166] The collaborative control unit, through the cooperation of the image acquisition device and the control device, achieves intelligent and precise regulation of system operation. The image acquisition device collects real-time images of the material during the screening process, and the control device extracts blockage and flow characteristics through image processing. Based on the recognition results, it automatically outputs adjustment commands to adjust the equipment operating parameters. Simultaneously, by recording adjustment parameters and output data, and counting the number of adjustments, it dynamically optimizes the blockage and flow thresholds when the number of adjustments exceeds the limit and the output deviation exceeds the standard, forming a closed-loop control mechanism. This effectively avoids equipment blockage and abnormal flow, ensures stable and efficient system operation, and reduces manual maintenance costs.

[0167] The system features a rationally designed unit structure with clear connections. Each subunit has clearly defined process steps and functions, ensuring both standardization and operability of the treatment process while achieving high-value utilization and full-component utilization of the oversize material from aged waste, thus overcoming the limitations of traditional treatment methods. Furthermore, the system's structural composition, process steps, control methods, and functional effects form a complete protection system, precisely matching the protection points of the claims, effectively preventing the circumvention of core technologies, and possessing significant practical and industry application value.

[0168] Example 2

[0169] This embodiment uses a case study of a remediation project for aged waste from an informal landfill (over 10 years old, with a volume of approximately 900,000 cubic meters). An investigation of the landfill revealed that the physical composition of the aged waste consisted of 57.87% lightweight materials (textiles, rubber and plastics, paper, wood and bamboo), approximately 19.66% inert materials (bricks, ceramics, and glass), 4.45% metals, and 11.80% ash and soil. The average moisture content was 39.82%, and the dry basis higher calorific value was 13676 kJ / kg. While possessing high potential for resource utilization, the high moisture content and high proportion of lightweight materials posed significant challenges to the stability and sorting accuracy of the screening process. This project fully adopted the aged waste oversize processing system technology of this invention, configuring two screening production lines with a daily processing capacity of 1156 tons. The core equipment configuration and connection relationships are as follows: Figure 2 and Figure 3 As shown in Table 1, the optimal operating parameters are as follows.

[0170] Table 1. Specifications of Main Equipment and Optimal Operating Parameters for the Screening Production Line

[0171] Equipment Name Main Specifications Adjustment range Optimal operating parameters Large screen 200mm sieve diameter Operating frequency 50Hz 50Hz Magnetic separator Maximum magnetic attraction force 20kg Belt speed 0-3m / s 2.0m / s Primary drum screen 100mm sieve diameter Operating frequency 0~50Hz 25-30Hz Secondary drum screen 40mm sieve diameter Operating frequency 0~50Hz 20-25Hz Star sieve 15~20mm sieve diameter Operating frequency 0~50Hz 15-20Hz Primary air separator Maximum air volume 24000m³ / h Operating frequency 0~50Hz 25-30Hz Secondary air separator Maximum air volume 24000m³ / h Operating frequency 0~50Hz 20-25Hz Three-stage air separator Maximum air volume 24000m³ / h Operating frequency 0~50Hz 15-20Hz Twin-shaft shear crusher Low-speed high-torque design 0-30rpm 15-25rpm

[0172] I. The production line operation process is as follows:

[0173] 1. After excavation and feeding, the aged waste enters the twin-shaft shear crusher and is homogenized and crushed at a speed of 18 rpm.

[0174] 2. After crushing, the material is sequentially passed through a large screen to separate large inert objects and a magnetic separator to recover ferromagnetic metals.

[0175] 3. After iron removal, the material enters the first-stage drum screen (28Hz), the second-stage drum screen (22Hz), and the star disk screen (18Hz) in sequence to complete the three-stage particle size classification. The humus under the star disk screen is directly sent to the corresponding collection area.

[0176] 4. The materials on each screen are fed into the primary air separator (28Hz), the secondary air separator (22Hz), and the tertiary air separator (18Hz) respectively to complete the gravity separation. The separated light combustibles and heavy materials are sent to the corresponding collection areas respectively.

[0177] 5. Industrial cameras deployed at key nodes throughout the line collect real-time images of the working conditions and transmit them to the PLC central control cabinet, where intelligent and coordinated control of the parameters of each device is achieved according to preset strategies.

[0178] II. Screening effect

[0179] After seven months of continuous and stable operation, the production line has achieved a total daily processing capacity of 2,312 tons, representing a nearly 30% increase in capacity compared to traditional aged waste screening processes. The screening products achieve high-purity separation, with average impurity levels of 1.10% for humus, 1.39% for heavy materials, and 0.56% for light materials, laying a solid foundation for subsequent high-value utilization. The intelligent control strategy of the collaborative control unit effectively addresses the challenges of handling materials with high moisture content during the rainy season, reducing equipment blockages by approximately 85% compared to traditional processes. It eliminates the need for on-site manual cleaning, significantly reducing labor costs and operational safety risks.

[0180] III. Resource Utilization Products and Economic Benefits

[0181] Based on the refined screening products of this system, and through the four parallel processing paths of the diversified resource utilization unit of this invention, the high-value utilization of all components of aged waste is realized, as detailed below:

[0182] 1. High-purity light combustibles are prepared into RDF fuel with a stable calorific value of over 14.6 MJ / kg. It is delivered to surrounding thermal power plants as an alternative fuel, with a sales price of 200 yuan / ton.

[0183] 2. Part of the humus is used for ecological restoration backfilling of landfills, and part is mixed with garden waste for composting to prepare organic matrix. The product price is 150 yuan / ton.

[0184] 3. Heavy inert materials are prepared into recycled aggregates, priced at 80 yuan / ton; ferromagnetic metals are recycled and sold externally, with scrap iron priced at 3000 yuan / ton, achieving full recovery of inert materials and metals.

[0185] Calculations show that the direct economic value of treating each ton of aged waste under this plan is approximately 150-200 yuan, and the unit treatment cost is reduced to 120 yuan / ton. Compared with traditional treatment methods, the efficiency is significantly improved, and the static investment payback period of the project is approximately 10.4 years, making it economically feasible.

[0186] IV. Comparative Analysis with Existing Blending Technologies

[0187] To verify the superior application of the screening products of this invention, taking the co-incineration of municipal solid waste as an example, the RDF prepared by the system's lightweight materials was used in co-processing experiments with raw waste at different ratios, and compared with a control group consisting of pure raw waste incineration. The results are as follows:

[0188] 1. Compatibility between calorific value and blending ratio: The formula for calculating the lower heating value of blended fuels is as follows: Where D is the blending ratio, in percentage. According to the formula, the blending ratio of low calorific value oversize material (impurity rate above 15%) in traditional coarse screening is usually limited to within 20%. The high-quality RDF (impurity rate 0.56%) prepared by this invention has a stable calorific value, and the blending ratio can be appropriately increased without affecting the furnace temperature stability, or more stable combustion conditions can be achieved at the same ratio.

[0189] 2. Stability of furnace temperature and steam output: Under a co-firing ratio of 15%-20%, the furnace temperature of both the test furnace and the control furnace remained stable above 850℃, with similar fluctuation ranges (see appendix). Figure 4 Although the evaporation rate of the test furnace boiler decreased slightly, it was still higher than the design rated value of 43.4 t / h, and had a minimal impact on the overall thermal economy (see appendix). Figure 5 This verifies that the screening products of the present invention can be adapted to conventional incineration co-processing conditions.

[0190] 3. Environmental performance and consumable consumption: Traditional coarse screening and co-firing often leads to an increase of more than 40% in the amount of quicklime used. With the high-purity light materials of this invention, the consumption of quicklime and urea fluctuates within ≤5% at a co-firing ratio of 1:1 to 1:3, with no significant increase. The slag yield increases slightly but is still within the design range. All emission indicators of flue gas are stably compliant and far below the limit requirements of the "Standard for Pollution Control of Municipal Solid Waste Incineration" GB18485-2014.

[0191] In summary, this embodiment fully verifies that the technical solution of the present invention is feasible and has significant advantages over the prior art, achieving a triple improvement in screening efficiency, product purity, and resource utilization benefits.

[0192] Example 3

[0193] Please see Figure 6 Figure 6 The flowchart illustrates the steps of a method for treating screened material from aged waste, as provided in an embodiment of the present invention.

[0194] This invention provides a method for treating the residue left on screens of aged garbage, comprising:

[0195] Step 601: Crush the aged waste to be processed to generate crushed material;

[0196] Step 602: The crushed material is subjected to multi-stage particle size screening and gravity separation in sequence to obtain multiple types of separated materials;

[0197] Step 603: Collect real-time images of the material during the screening process, identify the blockage status and flow rate of the material based on the real-time images, and output a coordinated adjustment control signal when the identification result is greater than a preset threshold.

[0198] Step 604: According to the preset conversion path, the corresponding sorted materials are converted into recycled products.

[0199] The specific implementation method of the old waste screening material treatment method is basically the same as the specific implementation of the above-mentioned refrigeration machine performance prediction system, and will not be repeated here.

[0200] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A system for treating waste screen residue from aged garbage, characterized in that, include: Pre-processing unit, multi-stage screening and sorting unit, collaborative control unit and resource utilization unit; The pretreatment unit is used to crush the aged waste to be processed to generate crushed material; The multi-stage screening and sorting unit is connected to the pretreatment unit and includes multiple screening devices and multiple air separation devices arranged sequentially along the material conveying direction. It is used to sequentially perform multi-stage particle size screening and gravity separation on the crushed material to obtain multiple types of sorted materials. The collaborative control unit is connected to the preprocessing unit and the multi-stage screening and sorting unit, and includes an image acquisition device and a control device; the image acquisition device is used to acquire real-time images of the material during the screening process. The control device is used to identify the blockage status and flow status of the material based on the real-time image, and when the identification result is greater than a preset threshold, output a coordinated adjustment control signal to the multi-stage screening and sorting unit. The resource utilization unit is connected to the multi-stage screening and sorting unit and is used to convert the corresponding sorted materials into recycled products according to a preset conversion path.

2. The system for treating stale waste screen residue according to claim 1, characterized in that, The plurality of screening devices include a large screen, a magnetic separator, a primary drum screen, a secondary drum screen, and a star-shaped screen connected in sequence along the material conveying direction; the plurality of air separation devices include a primary air separator, a secondary air separator, and a tertiary air separator; The feed inlet of the large-part screen is connected to the pretreatment unit, its upper discharge outlet is connected to the large inert material collection area, and its lower discharge outlet is connected to the feed inlet of the magnetic separator. The material outlet of the magnetic separator is connected to the inlet of the primary drum screen, and its metal outlet is connected to the metal collection area. The discharge port of the primary drum screen is connected to the inlet of the primary air classifier, and its discharge port is connected to the inlet of the secondary drum screen. The discharge port of the secondary drum screen is connected to the inlet of the secondary air separator, and its discharge port is connected to the inlet of the star disk screen. The upper discharge port of the star disk screen is connected to the inlet of the three-stage air separator, and its lower discharge port is connected to the humus collection area. The light material outlets of the primary, secondary, and tertiary air separators are connected to the light combustible material collection area, and the heavy material outlets are connected to the heavy material collection area.

3. The system for treating stale waste screen residue according to claim 1, characterized in that, The control device performs the following steps: Based on the real-time images acquired by the image acquisition device, the blockage status characteristics and flow status characteristics of the material during the screening process are identified and extracted. When the blockage state characteristic is greater than the blockage threshold, a first adjustment command is generated to reduce the operating frequency of the corresponding screening equipment, and a second adjustment command is generated simultaneously to increase the air volume of the corresponding air separation equipment. When the flow rate characteristic is greater than the flow rate threshold, a third adjustment command is generated to reduce the conveying speed of the material from the pretreatment unit to the multi-stage screening and sorting unit. Record and store the operating parameters and corresponding screening product output rate for each adjustment, and count the number of adjustments per unit time. When the number of adjustments exceeds a preset threshold, the congestion threshold and the flow threshold are adjusted based on the output rate data.

4. The system for treating stale waste screen residue according to claim 3, characterized in that, The step of identifying and extracting the blockage state characteristics and flow state characteristics of the material during the screening process based on the real-time images acquired by the image acquisition device includes: The real-time image acquired by the image acquisition device is converted to grayscale, and an edge detection algorithm is used to extract the edge contour of the sieve hole area to generate a sieve hole area mask. The real-time image is converted to a color space, and the material area is segmented according to the color difference threshold between the material and the screen to generate a material area mask; The material area mask and the sieve hole area mask are superimposed at the pixel level. The proportion of the number of pixels in the material area covering the sieve hole area to the total number of pixels in the sieve hole area is calculated to generate the blockage area ratio. The blockage area ratio is used as the blockage state feature. The pixel displacement of the material region in multiple consecutive real-time images is tracked, the average moving speed of the material per unit time is calculated, and the material throughput per unit time is estimated by combining the area of ​​the material region to generate instantaneous flow status features. Time-series analysis is performed on multiple consecutive frames of images within a preset time window to extract the changing trends of material area and material movement speed. Based on these changing trends, the material flow rate at a future preset time point is predicted, and flow trend characteristics are generated. The instantaneous flow state feature and the flow trend feature are used together as the flow state feature.

5. The system for treating stale waste screen residue according to claim 3, characterized in that, The step of adjusting the congestion threshold and the flow threshold based on the output rate data when the number of adjustments exceeds a preset threshold includes: Record the output rate of the screened product within a preset time period after each adjustment command is executed, and establish a data sequence of the output rate changing over time; Calculate the average value of the data sequence within the statistical period, and subtract the average value from the preset target output rate to obtain the output rate deviation value; When the number of adjustments exceeds a preset threshold and the absolute value of the output deviation is greater than a preset allowable deviation, the positive or negative direction of the output deviation is determined. If the output deviation value is negative and the number of adjustments is greater than the preset number threshold, then the blockage threshold and the flow threshold are increased by a first preset step size, and the original blockage threshold and flow threshold are replaced. If the output deviation value is negative and the number of adjustments is less than or equal to the preset number threshold, then the blockage threshold and the flow threshold are reduced by a second preset step size, and the original blockage threshold and flow threshold are replaced. If the output deviation is positive, the current congestion threshold and flow threshold remain unchanged.

6. The system for treating stale waste screen residue according to claim 1, characterized in that, The resource utilization unit includes a lightweight combustible material treatment subunit, a humus soil treatment subunit, an inert material treatment subunit, and a high-value plastic recycling subunit. A high-value plastic recycling subunit is located before the light combustible material processing subunit and is used to separate high-value plastics from the light combustible material in the sorting material and prepare them into recycled plastic pellets. The light combustible material processing subunit is used to prepare the light combustible material in the sorted material into waste-derived fuel; The humus treatment subunit is used to convert humus samples from the sorted materials into biologically processed organic matrix. An inert material processing subunit is used to prepare recycled aggregate from the heavy materials and large inert materials in the sorted materials.

7. The system for treating stale waste screen residue according to claim 6, characterized in that, The high-value plastic recycling subunit includes: A photoelectric sorting device is installed before the light combustible material processing subunit to separate high-value-added plastics from the light combustible material in the sorting material; A cleaning device is used to clean the high-value-added plastic to produce cleaned high-value-added plastic. The melt granulation device is used to melt and granulate the cleaned high-value-added plastic according to a preset melting temperature range to obtain recycled plastic granules.

8. The system for treating stale waste screen residue according to claim 6, characterized in that, The humus treatment subunit performs the following steps: Obtain a humus sample from the sorted material and test the organic matter content of the humus sample; Determine whether the organic matter content is greater than or equal to a preset organic matter threshold; If so, the humus sample is sent to an anaerobic digestion device and anaerobic digestion is carried out at a preset temperature and a preset volumetric load to produce biogas. If not, the humus sample is mixed with the preset auxiliary materials, the mixture is adjusted to the preset carbon-nitrogen ratio range and the preset moisture content range, and aerobic composting is carried out by forced ventilation and turning, so as to convert the mixture into a decomposed organic matrix or soil conditioner.

9. The system for treating stale waste screen residue according to claim 6, characterized in that, The inert material handling subunit performs the following steps: The heavy materials and large inert materials in the sorted materials are obtained and sent to the crushing device for crushing to generate crushed inert materials. The crushed inert material is fed into a screening device for screening to obtain recycled aggregate that meets the preset particle size requirements.

10. A method for treating the residue left on a screen of aged garbage, characterized in that, include: The aged waste to be processed is crushed to generate crushed material; The crushed material is subjected to multi-stage particle size screening and gravity separation in sequence to obtain multiple types of separated materials. Real-time images of the material during the screening process are collected, and the blockage and flow status of the material are identified based on the real-time images. When the identification result is greater than a preset threshold, a control signal for coordinated adjustment is output. According to the preset conversion path, the corresponding sorted materials are converted into recycled products.

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