Friction dry cleaning method with addition of biochar ceramsite and semi-plasticized recycled plastic aggregates

Abstract

The application discloses a friction dry washing method for adding biochar ceramic and semi-plasticized recycled plastic aggregate, and comprises the following steps: pretreating light materials screened from stock household garbage; setting two-stage series friction aggregate dry washing equipment: canceling the central shaft of the first-stage friction aggregate dry washing equipment and setting the rest according to ZL202111647195.5; the light materials enter the first-stage friction aggregate dry washing equipment added with biochar ceramic, the biochar ceramic is used for physically and chemically adsorbing and rubbing the surface of the light materials, so that volatile pollutants are adsorbed and the impurities adhered to the surface are stripped; the light materials enter the second-stage friction aggregate dry washing equipment added with semi-plasticized recycled plastic aggregate; the semi-plasticized recycled plastic aggregate is used for rubbing and colliding with the light materials and mechanically beating to promote friction, so that the impurities are further stripped and separated; and the biochar ceramic and the semi-plasticized recycled plastic aggregate are reused. The ordinary friction dry washing technology is upgraded to the aggregate friction dry washing, and the stripping and removal efficiency of the impurities can be obviously improved.

Description

Technical Field

[0001] This invention belongs to the field of friction cleaning technology and relates to a friction dry cleaning method, particularly a method for improving the friction dry cleaning and impurity removal efficiency of lightweight materials (hereinafter referred to as lightweight materials) on existing waste screens by adding biochar ceramic particles and semi-plasticized recycled plastic aggregates. Background Technology

[0002] Friction dry cleaning is a dry cleaning technology that uses mechanical friction between materials and between materials and added friction materials to remove impurities adhering to the materials. Compared with the disadvantages of wet cleaning processes, which generate a large amount of wastewater and are prone to secondary pollution, it has the significant advantage of not requiring water and not generating wastewater.

[0003] Commonly used friction dry cleaning technology utilizes the rubbing and friction collision between materials to remove impurities adhering to the surface of the materials. However, for soft materials, the dry cleaning effect is not good due to the low friction intensity.

[0004] Existing technologies address this problem by adding hard aggregates as friction materials. For example, Chinese patent CN111571862A discloses a dry cleaning device and method for waste plastics in municipal solid waste. In this method, a friction dry cleaning unit adds friction materials such as stones and metals to plastic fragments. The friction and collision between the plastic fragments and the friction materials causes contaminants to detach from the plastic fragments. Contaminants are then screened out using sieves with different apertures, separating the plastic fragments from the friction materials. The friction materials are then recycled and reintroduced into the friction dry cleaning unit's inlet. However, the friction materials used in this method, such as stones and metals, are highly hard, and the rotary friction process can easily accelerate the wear of the equipment. Furthermore, irregularly shaped friction materials can easily cut thin-film plastics, potentially causing changes in the material's dimensions and affecting the efficiency of separating the target substance according to its size.

[0005] Therefore, the friction dry cleaning technology that adds new friction materials to improve the efficiency of waste plastic friction dry cleaning without causing excessive wear inside the rotary equipment and without changing the size of the materials to be sorted will have important practical significance. Summary of the Invention

[0006] To address the problems existing in current waste plastic dry cleaning technologies, this invention provides a friction dry cleaning method that adds biochar ceramsite and semi-plasticized recycled plastic aggregate. This method can improve the efficiency of friction dry cleaning and impurity removal of lightweight materials on existing waste screens.

[0007] The technical solution of this invention is:

[0008] Friction dry cleaning methods involving the addition of biochar ceramsite and semi-plasticized recycled plastic aggregates include:

[0009] (1) Pretreatment of light material on the screen of existing domestic waste, used to remove large-sized, medium-sized impurities and ferromagnetic metal impurities respectively;

[0010] (2) Set up a two-stage series friction aggregate dry cleaning equipment. The two-stage friction aggregate dry cleaning equipment refers to the existing domestic waste screen light material friction dry cleaning equipment in ZL202111647195.5.

[0011] (3) The pretreated lightweight material enters the primary friction aggregate dry cleaning equipment; biochar ceramic particles are added to the primary friction aggregate dry cleaning equipment; the biochar ceramic particles adsorb some volatile pollutants and remove impurities adhering to the surface by physicochemical adsorption and rubbing and friction with the surface of the lightweight material; the biochar ceramic particles are recycled for reuse.

[0012] (4) The material is then put into the secondary friction aggregate dry cleaning equipment; semi-plasticized recycled plastic aggregate is added to the secondary friction aggregate dry cleaning equipment; through the friction and collision between the semi-plasticized recycled plastic aggregate and the lightweight material and the synergistic effect of mechanical beating, the impurities on the surface of the lightweight material are further peeled off and separated; the semi-plasticized recycled plastic aggregate is recycled for reuse.

[0013] Furthermore, the two-stage series friction aggregate dry cleaning equipment: the first-stage friction aggregate dry cleaning equipment omits the central shaft vibrating roller, and the remaining equipment is set up according to the friction dry cleaning equipment for lightweight materials on the screen of existing municipal solid waste as described in ZL202111647195.5; the second-stage friction aggregate dry cleaning equipment directly refers to the friction dry cleaning equipment for lightweight materials on the screen of existing municipal solid waste as described in ZL202111647195.5.

[0014] Furthermore, the pretreatment includes: sequentially feeding the material into the scale equalizer → primary manual sorting platform → primary friction soil washing unit → secondary friction soil washing unit → secondary manual sorting platform → primary magnetic separation unit → primary coarse crushing unit → secondary magnetic separation unit.

[0015] Furthermore, the primary and secondary friction soil washing units are connected sequentially and both employ friction soil washing equipment. The friction soil washing equipment includes a two-section drum, a feeding and discharging system, and a drive system. The inlet of the two-section drum is inclined higher than the outlet. The front section is a mixing section without screen holes, and the rear section is a separation section with screen holes. The mixing section and the separation section are connected, and the length ratio of the mixing section to the separation section is set to 1:1 to 1:3. The feeding and discharging system includes a lightweight material feeder, a humus feed pipe, a humus discharger, and a lightweight material discharger. The ends of the lightweight material feeder and the humus feed pipe are connected to the inlet of the two-section drum. The humus discharger is located below the two-section drum to collect and transport the screened humus. The lightweight material discharger is connected to the outlet of the two-section drum. The drive system includes a motor and reducer, a power roller, and a transmission roller. The motor controls the rotation of the power roller to achieve stable rotation of the shaftless two-section drum.

[0016] Furthermore, the process of dry cleaning using humus in the aforementioned friction soil washing equipment is as follows: After the two-section drum rotates and the speed stabilizes, the light material on the screen of the existing domestic waste containing water and the humus are conveyed into the mixing section. The mass ratio of light material to humus is set to 1:2 to 1:5; the moisture content of the light material is 30% to 60%; the moisture content of the humus is 8% to 20%, and the particle size is less than 10mm. Through the continuous rotation of the mixing section, the humus is evenly dispersed into the light material, and the humus acts as a friction agent, constantly colliding and rubbing against the light material. The dry, small-particle-size humus easily enters the gaps between the light material piles, absorbs and transfers the surface moisture of the light material, and adsorbs the malodorous gases in the light material. The separation section separates the friction agent, impurities peeled off from the light material, and clean light material, and recycles them through different discharge ports.

[0017] Furthermore, the amount of biochar ceramic particles added is 1-5 times the amount of light material fed; the particle size of the biochar ceramic particles is 5-15 mm.

[0018] Furthermore, the method for preparing the biochar ceramic particles includes:

[0019] Step 1): The dewatered cement cake from high-moisture-content biomass waste is pretreated by heating and stirring;

[0020] Step 2): Mechanically dehydrate the pretreated material and use it as the main material; use fly ash, phosphogypsum and lime from industrial waste as auxiliary materials, and mix the main material and auxiliary materials thoroughly.

[0021] Step 3): The above mixture is processed into granules using pressure molding technology;

[0022] Step 4): The above wet-based columnar particles are sent to the inlet of the horizontal rotary aerobic pyrolysis furnace. The wet-based columnar particles are then subjected to a preheating and drying section for waste heat tail gas, a rotary section for low-temperature aerobic pyrolysis, and a short-term treatment section for instantaneous combustion to obtain dry-based particles.

[0023] Step 5): The dry-based particles are cured in a wet curing tank by water mist humidification and electric heating temperature control to obtain the biochar ceramic particles.

[0024] Furthermore, in step 2): the moisture content of the main material is 40-60%, and the total mass percentage of the main material is 40%-60%; the fly ash, phosphogypsum and lime in the auxiliary materials are mixed in a mass ratio of approximately 8:1:(1-1.5), and the total mass percentage of the auxiliary materials is approximately 40-60%; the main and auxiliary materials are respectively added to an intermittently operating horizontal mixing tank by screw conveyor and then thoroughly mixed.

[0025] Step 3): The mixture is processed into wet-based columnar particles with a diameter of 5-10 mm and a length of 5-10 mm by pressure molding, and the moisture content of the wet-based columnar particles is 30-40%.

[0026] Step 4): The temperature rise of the waste heat exhaust gas preheating and drying section is 100-200℃, and the moisture content of the wet base columnar particles is reduced to 20-30%; the temperature of the low temperature aerobic pyrolysis section is 250-350℃, and the particle slow rotation residence time is 30-50 minutes; the instantaneous combustion treatment is 250-350℃.

[0027] Step 5): Electric heating temperature control at 45-55℃, curing time 4-6 days.

[0028] Furthermore, the amount of semi-plasticized recycled plastic aggregate added is 1-5 times the amount of lightweight material fed; the particle size of the semi-plasticized recycled plastic aggregate is 20-30mm.

[0029] The beneficial effects of this invention are:

[0030] (1) The method of the present invention upgrades the ordinary friction dry cleaning technology to aggregate friction dry cleaning, which can significantly improve the efficiency of impurity removal.

[0031] (2) The biochar ceramic particles added during the friction dry washing of primary aggregate in the method of the present invention have physicochemical adsorption properties. They can not only further degrade the moisture content of light materials, but also adsorb and remove volatile pollutants and odorous gases on the surface of light materials.

[0032] (3) The semi-plasticized recycled plastic aggregate added in the secondary aggregate friction dry cleaning method of the present invention has an irregular shape and good mechanical strength. By utilizing the irregular shape combined with the friction beater to assist the stirring action, the friction collision of pollutants on the surface of lightweight materials can be strengthened and the peeling efficiency can be improved. The impurity removal rate of the secondary aggregate after friction dry cleaning can reach 70% to 90%.

[0033] (4) Using the method of the present invention, the surface impurities and friction aggregates that are peeled off are easily separated due to the large difference in particle size and density, which can realize the recycling of aggregates.

[0034] (5) Compared with the drawbacks of the "wet" cleaning process, which generates a large amount of wastewater and is prone to secondary pollution, the method of the present invention does not require water and does not generate wastewater, thus saving water resources. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the equipment for friction washing of humus soil;

[0036] 1-Mixing section roller, 2-Separation section roller, 3-Light material feed belt, 4-Humus feed pipe, 5-Humus discharge belt, 6-Light material discharge belt, 7-Motor and reducer, 8-Power roller, 9-Transmission roller, 10-Guide chute, 11-Screw hole, 12-Screw conveyor. Detailed Implementation

[0037] The present invention will be further described below with reference to the embodiments.

[0038] Example 1:

[0039] A friction dry cleaning method using biochar ceramsite and semi-plasticized recycled plastic aggregate, specifically a method for improving the friction dry cleaning efficiency of lightweight materials on the screens of existing municipal solid waste by adding biochar ceramsite and semi-plasticized recycled plastic aggregate, including:

[0040] The pretreatment process of lightweight materials before the aggregate friction dry cleaning equipment is as follows: scale plate equalizer → primary manual sorting platform → primary friction soil washing unit → secondary friction soil washing unit → secondary manual sorting platform → primary magnetic separation unit → primary coarse crushing unit → secondary magnetic separation unit.

[0041] The system consists of several stages: a primary manual sorting platform for sorting large-sized impurities, removing larger-sized textiles, leather, rubber, and wood impurities from lightweight materials; a primary and secondary friction washing unit for removing impurities from lightweight materials by adding humus; a secondary manual sorting platform for sorting medium-sized impurities; a primary magnetic separation unit for separating large ferromagnetic metals from lightweight materials; a primary coarse crushing unit for crushing lightweight materials using a biaxial shearing process to facilitate subsequent magnetic separation; and a secondary magnetic separation unit for separating small ferromagnetic metals from lightweight materials.

[0042] Specifically, regarding the primary and secondary friction soil washing units, the primary and secondary friction soil washing units are connected sequentially, and both can adopt methods such as... Figure 1The friction soil washing equipment shown (friction dry washing equipment for humus soil of light material on existing garbage screens) includes a two-section drum main unit, a feeding and discharging system and a drive system; the inlet of the two-section drum main unit is set at an angle higher than the outlet. The entire shaftless drum is integrated into two sections. The front section is the mixing section drum 1, which is a metal drum without screen holes; the rear section is the separation section drum 2, which is a metal drum with screen holes (the mixing section drum 1 and the separation section drum 2 are connected, that is, the front end of the entire inclined drum is not perforated, and the rear end is perforated. The material is input into the drum from the inlet. It needs to be continuously rotated by the drum and the tilt angle of the drum itself to be displaced in the axial direction of the drum. At the same time, the rolling of the drum itself plays a role in stirring and mixing. Therefore, the material will definitely go through the process from the mixing section drum 1 to the separation section drum 2 and be mixed in the mixing section drum 1). The feeding and discharging system includes a lightweight material feeding belt 3, a humus feeding pipe 4, a humus discharging belt 5, and a lightweight material discharging belt 6. The ends of the lightweight material feeding belt 3 and the humus feeding pipe 4 are connected to the drum inlet. The humus feeding pipe 4 uses a screw conveyor 12 to achieve quantitative and uniform conveying of humus. The humus discharging belt 5 is located below the drum and is used to collect and convey the screened humus. The lightweight material discharging belt 6 is connected to the drum outlet and is located on the lower side of the bottom of the drum outlet to transport the dry-cleaned lightweight materials. The drive system includes a motor and reducer 7, a power roller 8, and a transmission roller 9. The motor controls the rotation of the power roller 8 through a linkage device to achieve stable rotation of the shaftless drum (shaftless drums are a mature existing technology, mainly in the following ways: relying on the motor to drive the meshing small gear and the large gear of the drum to rotate, or the chain meshing with the gear on the drum, and the motor driving the chain drive, or the drum is placed on two idler rollers, and the motor driving the idler roller drive).

[0043] Furthermore, the inclination angle of the two-section drum main unit is set at 3-15°, the total length of the drum is set at 5-10m, the inner diameter is set at 1-3m, and the length ratio of the mixing section drum 1 to the separating section drum 2 is set at 1:1 to 1:3 to achieve a better separation effect between the clay and the plastic. The screen holes of the separating section drum 2 are preferably distributed in a plum blossom pattern, with a screen hole diameter of 20-40mm and a center-to-center spacing of 40-100mm; the screen hole shape can be circular or regular polygonal, preferably circular. The two-section drum main unit is preferably made of corrosion-resistant carbon steel or stainless steel.

[0044] Furthermore, the width of the lightweight material feed belt 3 is set to 0.6–1.2 m, with its midpoint located at the center of the drum inlet section. The center of the humus feed pipe 4 is set 0.25–0.40 m below the top of the drum, with its end exactly on the drum inlet section, and its diameter is set to 0.16–0.35 m. The width of the lightweight material discharge belt 6 is set to 0.6–2 m, and it is set 0.2–0.5 m below the bottom of the drum outlet. The humus discharge belt 5 is set horizontally or flush with the drum, with a belt width of 0.6–2 m, and it is set 0.3–0.8 m below the bottom of the drum outlet.

[0045] The process of friction dry cleaning of lightweight materials using the above-mentioned friction soil washing equipment is as follows: The drive system is turned on, and the shaftless drum begins to rotate until it reaches the set speed (10-20 rpm). After the speed stabilizes, the lightweight materials on the screen of the existing municipal solid waste with a moisture content of 30%-60% are conveyed into the mixing section drum 1 using the lightweight material feed belt 3. Simultaneously, humus soil with a moisture content of 8%-20% and a particle size of less than 10 mm (preferably less than 5 mm) is conveyed using the screw conveyor 12. The mass ratio of lightweight materials to humus soil is set to 1:2-1:5. The function of the mixing section drum 1 is to evenly disperse humus soil particles into the lightweight materials through continuous rotation of the drum, and to continuously collide and rub against the lightweight materials as a friction agent. The relatively dry, small-particle-size humus soil easily enters the gaps between the lightweight materials, absorbing and transferring surface moisture to the soil particles, and simultaneously adsorbing malodorous gases from the lightweight materials, thereby reducing the moisture content of the lightweight materials and removing volatile malodorous gases. The function of the separating section roller 2 is to separate the abrasive and impurities stripped from the light material from the clean light material, and to recover them through different discharge ports. By thoroughly rubbing the humus particles against the relatively dry light material, impurities adhering to the surface of the light material can be removed. Combined with the reasonably sized and densely distributed sieve holes in the separating section, the light material is separated from the humus and stripped impurities. The humus and stripped impurities reach the humus discharge belt via the guide chute; the clean light material is discharged from the separating section outlet and output via the light material discharge belt. After being left to dry in the field or treated with hot air drying, the moisture content of the humus and soil impurities decreases to 8%–20%. The above operating steps are repeated, and it is then used as a friction agent in the humus friction dry cleaning equipment.

[0046] The core innovation of this friction soil washing unit lies in the use of humus as the material (friction agent) for friction dry cleaning, which reduces the moisture content of light materials on the screen at a low cost and adsorbs polluting gases. The equipment is divided into a mixing section and a separation section according to the needs of dry cleaning material addition, and the two sections are innovatively integrated into a single device. The structure is simple and the cost is low. At the same time, it has a good dry cleaning effect on light materials with high moisture content (especially waste plastics). Specifically: (1) Compared with conventional friction agents such as stones and metal blocks, humus has special physicochemical properties such as hygroscopicity and adsorption. Using humus as a friction agent can not only reduce the moisture content of light materials, but also adsorb volatile organic gases and other malodorous gases. At the same time, the particle size of humus is small, and the dry cleaning effect of light materials is good, which is conducive to improving the quality of subsequent recycled plastic products and increasing the economic benefits of waste plastic resource utilization. (2) After the humus and stripped impurities are screened out, since their physical and chemical properties have not changed significantly, they can be reused as a friction agent, saving the cumbersome process of separating the friction agent and impurities and saving operating costs. (3) The mixing section and separation section of the humus friction washing equipment are integrated, making the equipment simpler, easier to operate, and saving construction costs. Moreover, by integrating the mixing section and separation section into the drum, it is not necessary to mix them in other equipment before entering the drum for separation, which can save reaction steps and reaction time. (4) Adjusting the length ratio of the mixing section and the separation section, as well as the mass ratio of light materials to humus, can adjust the dry washing effect of light materials; generally, the smaller the mass ratio of light materials to humus, the better the dry washing effect.

[0047] Second, the pretreated lightweight material is treated by adding biochar ceramsite and semi-plasticized recycled plastic aggregate to improve the efficiency of friction dry cleaning and impurity removal. The specific process is as follows:

[0048] (a) Setting up a two-stage series friction aggregate dry cleaning equipment: Based on the existing friction dry cleaning technology and equipment (referring to the friction dry cleaning equipment for lightweight materials on the screen of existing domestic waste in the specific implementation of Chinese Patent ZL202111647195.5, a friction dry cleaning equipment and method for lightweight materials on the screen of existing domestic waste), biochar ceramic particles with a particle size of 5mm and semi-plasticized recycled plastic aggregate with a particle size of 20mm are added respectively to form a first-stage friction aggregate dry cleaning equipment and a second-stage friction aggregate dry cleaning equipment with added biochar ceramic particles and semi-plasticized recycled plastic aggregate respectively, thereby upgrading the original friction dry cleaning technology to friction aggregate dry cleaning technology;

[0049] (b) The primary friction aggregate dry cleaning equipment eliminates the central shaft beater of the friction dry cleaning equipment in Chinese patent ZL202111647195.5, retaining only a rotating drum with an opening diameter of 15-20mm (preferably 15mm). (The reason for eliminating the central shaft beater in the primary friction aggregate dry cleaning equipment is that the density of waste plastic is too low. In actual engineering scales, the volume of waste plastic corresponding to a processing capacity of 10t / h is quite large. Although the setting of the central shaft beater can enhance the cleaning effect, its presence will also lead to an increase in processing load and a decrease in efficiency. At the same time, the large torque is prone to shaft breakage. Biochar ceramic particles are continuously added from the inlet end using a screw conveyor in proportion. Utilizing its physicochemical adsorption effect and the rubbing and friction effect with the surface of lightweight materials, some volatile pollutants are adsorbed and impurities adhering to the surface are peeled off. The peeled-off impurities are separated through the sieve holes due to the size difference between them and the waste plastic material.

[0050] The amount of biochar ceramsite added is 2.5 times the amount of light material fed in;

[0051] Biochar ceramic particles need to possess a certain level of mechanical strength and adsorption capacity to prevent breakage during the dry cleaning process and to adsorb any foul-smelling gases produced. Other biochar ceramic particles that meet the above requirements can also be used.

[0052] Preferably, the biochar ceramsite is prepared using the following production method (the advantage of this method is that the raw material for the dewatering cake comes from the mud and water generated during the waste plastic washing process, which can realize waste treatment and reduce the amount of external materials input into the system):

[0053] Step 1): Add a small amount of lime to the dewatered cement cake of high-moisture biomass waste and heat and stir it for pretreatment to release bound water;

[0054] Preferably, in step 1), the high-moisture-content biomass waste is dewatered sludge from sewage treatment plants, algae sludge obtained by dredging from lakes and reservoirs and separating algae from water, etc., the moisture content of the dewatered sludge cake is 70-90%, the heating and stirring temperature is 50-70℃, and the total mass percentage of lime is 5%-10%.

[0055] Step 2): Use mechanical dewatering technology (such as plate and frame filter press or screw press) to further reduce the moisture content of the material as the main material; prepare fly ash, phosphogypsum and lime from industrial waste in a certain mass ratio as auxiliary materials; crush waste plastic residue and add it according to a certain mass ratio of the main and auxiliary materials; the main and auxiliary materials are added to the intermittently running horizontal mixing tank by screw conveyor to be fully mixed evenly.

[0056] Preferably, in step 2), the moisture content of the main material is 40-60%, and the total mass percentage of the main material is 40%-60%; the auxiliary materials are all from industrial waste, among which fly ash, phosphogypsum and lime are dry powder materials with low moisture content, prepared in a mass ratio of about 8:1:(1-1.5), and the total mass percentage is about 40-60%; waste plastic residue is crushed to less than 2mm and added at a ratio of 5-7% of the mass of the main and auxiliary mixture. The main and auxiliary materials are added to the intermittently operating horizontal mixing tank by screw conveyor and fully mixed evenly.

[0057] Step 3) Use various pressure molding techniques to process the mixture into granules so that it is heated evenly during the pyrolysis and incineration process and is not easily dispersed after solidification;

[0058] Preferably, in step 3), the well-stirred mixture is uniformly fed into the inlet of a twin-screw extruder. The extruder die head uses a 5mm perforated plate and is equipped with an automatic scraper. The mixture is processed by pressure molding into wet-based columnar particles with a diameter of 5-10mm and a length of 5-10mm (moisture content 30-40%), and the particle size is 5-10mm.

[0059] Step 4) The wet-based columnar particles are conveyed to the inlet of the horizontal rotary aerobic pyrolysis furnace via a belt conveyor. The wet-based columnar particles are preheated and dried in the waste heat tail gas preheating and drying section to reduce their moisture content. They then enter the low-temperature aerobic pyrolysis section, where the particles slowly rotate. During this process, aerobic pyrolysis releases heat. Electric heating and temperature control are implemented to precisely control the aerobic pyrolysis temperature, thereby reducing the amount of combustible gas produced to below its explosive limit concentration and simultaneously reducing the amount of liquid phase products. Finally, the particles enter the instantaneous combustion section, using natural gas or other combustible gases as fuel. An annular porous burner technology is used to perform short-term combustion treatment on the particles to burn off liquid phase products. Finally, the dry-based particle product is discharged from the pyrolysis furnace outlet, naturally cooled in the air-cooling section, and then enters the wet curing tank. The air-cooling section draws in air to cool the dry-based particles, and the resulting waste heat tail gas is returned to the inlet preheating and drying section, forming a waste heat recycling system.

[0060] The advantage of this three-step heat treatment process for wet-based columnar particles lies in the following: First, the particles are preheated using the residual heat from combustion, which raises the temperature and reduces the moisture content. Furthermore, the residual heat from combustion is effectively utilized. Second, the preheated particles undergo aerobic pyrolysis, with precise temperature control to reduce the amount of combustible gas produced, keeping it below its explosive limits, while also minimizing the production of liquid phase products. Finally, the particles undergo a transient combustion treatment stage to burn off the liquid phase products. This three-stage heat treatment further solidifies harmful substances in the biochar and enhances the mechanical strength of the particles.

[0061] Preferably, in step 4), the wet-based columnar particles are preheated to 100-200℃ in the waste heat exhaust gas preheating and drying section, reducing the moisture content to 20-30%; the temperature in the low-temperature aerobic pyrolysis section is 250-350℃, and the particles slowly rotate and remain in the pyrolysis section for 30-50 minutes. The temperature of the instantaneous combustion treatment is 250-350℃.

[0062] Step 5) The dry-based granules are cured in a wet curing tank for a period of time by water mist humidification and electric heating temperature control to obtain the environmentally friendly biochar ceramsite product.

[0063] Preferably, in step 5), the electric heating temperature is controlled at 45-55℃, and the curing time is 4-6 days;

[0064] Step 6) Due to oxygen consumption during the waste heat recycling of exhaust gas, it is necessary to periodically discharge recirculated gas (exhaust gas) and replenish air according to the oxygen concentration in the exhaust gas to restore and ensure the oxygen concentration of the recirculated gas, thus ensuring the oxygen demand of aerobic pyrolysis. The discharged recirculated gas is first cooled and preheated by an air-cooled heat exchanger, and then volatile pollutants are removed by a humus fixed bed before being discharged at high altitude after meeting the standards.

[0065] Preferably, in step 6), 40%-60% of the recirculated gas (exhaust gas) is periodically discharged and 40%-60% of the air is replenished according to the oxygen concentration in the exhaust gas, thereby restoring and ensuring that the oxygen concentration of the recirculated gas is not lower than 5%-20%.

[0066] After passing through the aforementioned primary friction aggregate dry washing equipment, the surface impurities of the lightweight material that have been peeled off and separated are mixed with biochar ceramic particles. The impurities are then separated using a 5×15mm long-hole tension screen, and the biochar ceramic particles are recycled for reuse.

[0067] (c) Entering the series two-stage friction aggregate dry cleaning equipment (the reason for the central shaft beating of the two-stage friction aggregate dry cleaning equipment retains Chinese patent ZL202111647195.5: after the aggregate is washed by the first-stage friction aggregate dry cleaning equipment, a large amount of impurities are discharged, the amount entering the second-stage friction aggregate dry cleaning equipment is reduced, and the processing load is also reduced, so it can participate in the central shaft beating for enhanced cleaning), the semi-plasticized recycled plastic aggregate is continuously added from the inlet end by the screw conveyor in proportion to the rotating drum with an opening diameter of 30mm (the opening diameter on the rotating drum is 30-35mm). Through the frictional collision between the aggregate and the lightweight material and the synergistic effect of the mechanical beating to promote friction, the impurities on the surface of the lightweight material are further peeled off and separated;

[0068] Similarly, the lightweight material surface impurities and semi-plasticized recycled plastic aggregate mixture that are peeled off and separated are then separated by a 5×15mm long-hole tension screen to remove impurities and recycle the semi-plasticized recycled plastic aggregate for reuse.

[0069] The amount of the semi-plasticized recycled plastic aggregate added is 2.5 times the amount of lightweight material fed in; the semi-plasticized recycled plastic aggregate in this embodiment is semi-plasticized recycled plastic aggregate produced by DJ-230 extrusion dryer equipment (Zhangjiagang Dajiang Machinery Co., Ltd.).

[0070] The results of applying the method of adding aggregate to lightweight materials in Example 1 to improve the efficiency of friction dry cleaning for removing impurities are as follows:

[0071] (1) Upgrading from friction dry cleaning to aggregate friction dry cleaning can significantly improve the efficiency of impurity removal.

[0072] (2) The biochar ceramic particles added during the friction dry cleaning of primary aggregates have physicochemical adsorption properties. They can not only further degrade the moisture content of light materials, but also adsorb and remove volatile pollutants and odorous gases on the surface of light materials.

[0073] (3) The semi-plasticized plastic aggregate added in the secondary aggregate friction dry cleaning is irregular in shape and has good mechanical strength. By utilizing the irregular shape combined with the friction beater to assist the stirring action, the friction collision of pollutants on the surface of lightweight materials can be strengthened and the peeling efficiency can be improved. The impurity removal rate of the secondary aggregate friction dry cleaning can reach 80%.

[0074] (4) The surface impurities stripped from the friction aggregate (biochar ceramsite and semi-plasticized recycled plastic aggregate) are easily separated from each other due to their large differences in particle size and density, thus enabling the recycling of aggregates.

[0075] Example 2:

[0076] A friction dry cleaning method using biochar ceramsite and semi-plasticized recycled plastic aggregate, specifically a method for improving the friction dry cleaning efficiency of lightweight materials on the screens of existing municipal solid waste by adding biochar ceramsite and semi-plasticized recycled plastic aggregate, including:

[0077] First, the pretreatment of lightweight materials before the aggregate friction dry cleaning equipment is the same as in Example 1, and will not be repeated here.

[0078] Secondly, biochar ceramsite and semi-plasticized recycled plastic aggregate are added to the pretreated lightweight material to improve the efficiency of friction dry cleaning and impurity removal. The specific process is as follows:

[0079] (a) Setting up a two-stage series friction aggregate dry cleaning equipment: Based on the existing friction dry cleaning technology and equipment (referring to Chinese Patent ZL202111647195.5 A friction dry cleaning equipment and method for lightweight materials on the screen of existing municipal solid waste), biochar ceramic particles with a particle size of 15mm and semi-plasticized recycled plastic aggregate with a particle size of 30mm are added respectively to form a first-stage friction aggregate dry cleaning equipment and a second-stage friction aggregate dry cleaning equipment with added biochar ceramic particles and semi-plasticized recycled plastic aggregate respectively, thus upgrading the original friction dry cleaning technology to friction aggregate dry cleaning technology;

[0080] (b) In the primary friction aggregate dry cleaning equipment, the central shaft is eliminated, and only a rotating drum with an opening diameter of 20mm is retained. Biochar ceramic particles are continuously added from the inlet end using a screw conveyor in proportion. Utilizing its physicochemical adsorption effect and the rubbing and friction with the surface of lightweight materials, some volatile pollutants are adsorbed and impurities adhering to the surface are peeled off. The peeled-off impurities are separated through the sieve holes due to the size difference between them and the waste plastic materials.

[0081] The amount of biochar ceramic particles added is 3.5 times the amount of light material feed; the preparation method of biochar ceramic particles is the same as in Example 1, and will not be repeated here.

[0082] After passing through the above-mentioned primary friction aggregate dry washing equipment, the surface impurities of the light material that are peeled off and separated are mixed with biochar ceramic particles. The impurities are then separated by a 5×15mm long hole tension screen, and the biochar ceramic particles are recycled for reuse.

[0083] (c) Enter the series two-stage friction aggregate dry cleaning equipment. Similarly, the semi-plasticized recycled plastic aggregate is continuously added from the inlet end to the rotating drum with an opening diameter of 35mm using a screw conveyor. Through the friction and collision between the aggregate and the lightweight material, as well as the synergistic effect of the mechanical beating rod to promote friction, the impurities on the surface of the lightweight material are further peeled off and separated.

[0084] Similarly, the surface impurities of the lightweight material and the mixture of semi-plasticized recycled plastic aggregates that have been peeled off and separated are then separated by a 5×15mm long-hole tension screen to remove impurities and recycle the semi-plasticized recycled plastic aggregates for reuse.

[0085] The amount of the semi-plasticized recycled plastic aggregate added is 3.5 times the amount of lightweight material fed in; the semi-plasticized recycled plastic aggregate in this embodiment is semi-plasticized recycled plastic aggregate produced by DJ-230 extrusion dryer equipment (Zhangjiagang Dajiang Machinery Co., Ltd.).

[0086] The results of applying the method of adding aggregate to lightweight materials to improve the efficiency of friction dry cleaning for impurity removal in Example 2 are as follows:

[0087] (1) Upgrading from friction dry cleaning to aggregate friction dry cleaning can significantly improve the efficiency of impurity removal.

[0088] (2) The biochar ceramic particles added during the friction dry cleaning of primary aggregates have physicochemical adsorption properties. They can not only further degrade the moisture content of light materials, but also adsorb and remove volatile pollutants and odorous gases on the surface of light materials.

[0089] (3) The semi-plasticized plastic aggregate added in the secondary aggregate friction dry cleaning is irregular in shape and has good mechanical strength. By utilizing the irregular shape combined with the friction beater to assist the stirring action, the friction collision of pollutants on the surface of lightweight materials can be strengthened and the peeling efficiency can be improved. The impurity removal rate of the secondary aggregate friction dry cleaning can reach 90%.

[0090] (4) Due to the large differences in particle size and density, the surface impurities stripped from the friction aggregate are easy to separate and the aggregate can be recycled.

[0091] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the above embodiments do not limit the scope of protection of the present invention in any way, and all technical solutions obtained by equivalent substitution or other means fall within the scope of protection of the present invention.

Claims

1. A friction dry cleaning method with the addition of biochar ceramsite and semi-plasticized recycled plastic aggregates, characterized in that, include: (1) Pretreatment of lightweight materials on the screen of existing domestic waste; The pretreatment includes: sequentially feeding the material into a scale plate equalizer → a primary manual sorting platform → a primary friction soil washing unit → a secondary friction soil washing unit → a secondary manual sorting platform → a primary magnetic separation unit → a primary coarse crushing unit → a secondary magnetic separation unit; the primary and secondary friction soil washing units are connected sequentially and both use friction soil washing equipment; the friction soil washing equipment includes a two-section drum, a feeding and discharging system, and a drive system; the inlet of the two-section drum is inclined higher than the outlet, the front section is a mixing section without screen holes, and the rear section is a separation section with screen holes, the mixing section and the separation section are connected; the feeding and discharging system includes a light material feeder, a humus feed pipe, a humus discharger, and a light material discharger; the ends of the light material feeder and the humus feed pipe are connected to the inlet of the two-section drum; the humus discharger is located below the two-section drum to collect and transport the screened humus; the light material discharger is connected to the outlet of the two-section drum; (2) Install a two-stage series friction aggregate dry cleaning equipment; (3) The pretreated lightweight material enters the primary friction aggregate dry cleaning equipment; biochar ceramic particles are added to the primary friction aggregate dry cleaning equipment; the biochar ceramic particles adsorb some volatile pollutants and remove impurities adhering to the surface by physicochemical adsorption and rubbing and friction with the surface of the lightweight material; the biochar ceramic particles are recycled for reuse. (4) The material is then put into the secondary friction aggregate dry cleaning equipment; semi-plasticized recycled plastic aggregate is added to the secondary friction aggregate dry cleaning equipment; through the friction and collision between the semi-plasticized recycled plastic aggregate and the lightweight material and the synergistic effect of mechanical beating, the impurities on the surface of the lightweight material are further peeled off and separated; the semi-plasticized recycled plastic aggregate is recycled for reuse.

2. The method of dry abrasive washing with biochar ceramsite and semi-plasticized recycled plastic aggregate according to claim 1, characterized in that, The length ratio of the mixing section to the separation section is set to 1:1 to 1:3; the drive system includes a motor and reducer, a power roller and a transmission roller, and the motor controls the rotation of the power roller to achieve stable rotation of the shaftless two-section drum.

3. The method of dry abrasive washing with biochar ceramsite and semi-plasticized recycled plastic aggregate according to claim 2, characterized in that, The process of dry cleaning using humus in the aforementioned friction soil washing equipment is as follows: After the two-section drum rotates and the speed stabilizes, it conveys the light material and humus from the screen of the existing domestic waste containing water into the mixing section. The mass ratio of light material to humus is set to 1:2 to 1:5; the moisture content of the light material is 30% to 60%; the moisture content of the humus is 8% to 20% and the particle size is less than 10mm. Through the continuous rotation of the mixing section, the humus is evenly dispersed into the lightweight material, and the humus acts as a friction agent to continuously collide and rub against the lightweight material; the dry, small-particle-size humus easily enters the gaps between the lightweight materials, absorbs and transfers the surface moisture of the lightweight materials, and adsorbs the malodorous gases in the lightweight materials. The separation section separates the impurities detached from the friction agent and lightweight materials from the clean lightweight materials, and recycles and reuses them through different discharge ports.

4. The method of dry attrition scrubbing with biochar ceramsite and semi-plasticized recycled plastic aggregate according to any one of claims 1-3, characterized in that, The amount of biochar ceramic particles added is 1-5 times the amount of light material fed; the particle size of the biochar ceramic particles is 5-15 mm.

5. The method of dry abrasive washing with biochar ceramsite and semi-plasticized recycled plastic aggregate according to claim 4, characterized in that, The method for preparing the biochar ceramic particles includes: Step 1): Pre-treat the dewatered cake from high-moisture-content biomass waste by heating and stirring; Step 2): The pretreated material is mechanically dehydrated and used as the main material; fly ash, phosphogypsum and lime from industrial waste are used as auxiliary materials. The main material and auxiliary materials are thoroughly mixed and stirred evenly. Step 3): The mixture is processed into granules using pressure molding technology; Step 4): The mixture is pressure-formed into wet-based columnar particles with a diameter of 5-10 mm and a length of 5-10 mm. The wet-based columnar particles are sent to the inlet of the horizontal rotary aerobic pyrolysis furnace. The wet-based columnar particles are then subjected to preheating and drying in the waste heat tail gas section, rotation in the low-temperature aerobic pyrolysis section, and short-term treatment in the instantaneous combustion section to obtain dry-based particles. Step 5): The dry-based particles are cured in a wet curing tank by water mist humidification and electric heating temperature control to obtain the biochar ceramic particles.

6. The method of dry abrasive washing with biochar ceramsite and semi-plasticized recycled plastic aggregate according to claim 5, characterized in that, Step 2): The moisture content of the main material is 40-60%, and the total mass of the main material accounts for 40%-60%; the fly ash, phosphogypsum and lime in the auxiliary materials are mixed in a mass ratio of 8:1:(1-1.5), and the total mass of the auxiliary materials accounts for 40-60%; the main and auxiliary materials are respectively added to an intermittently running horizontal mixing tank by screw conveyor and then fully mixed evenly. Step 3): The moisture content of the wet-based columnar particles is 30-40%; Step 4): The temperature rise of the waste heat exhaust gas preheating and drying section is 100-200℃, and the moisture content of the wet base columnar particles is reduced to 20-30%; the temperature of the low temperature aerobic pyrolysis section is 250-350℃, and the particle slow rotation residence time is 30-50 minutes; the instantaneous combustion treatment is 250-350℃. Step 5): Electric heating temperature control at 45-55℃, curing time 4-6 days.

7. The friction dry cleaning method for adding biochar ceramsite and semi-plasticized recycled plastic aggregate as described in any one of claims 1-2, characterized in that, The amount of semi-plasticized recycled plastic aggregate added is 1-5 times the amount of lightweight material fed; the particle size of the semi-plasticized recycled plastic aggregate is 20-30mm.

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