A process method for thermal sorting and quality improvement of domestic waste and the upgraded biomass powder obtained therefrom

Abstract

The present invention provides a process method for thermal sorting and quality improvement of domestic waste and the quality-improved biomass powder obtained therefrom, relating to the technical field of solid waste treatment. The process method comprises the following steps: coarsely crushing domestic waste to obtain crushed materials with a particle size ≤ 100 mm; subjecting the crushed materials to ripening and dehydration, and performing drying after the leachate flows out to obtain dried materials; performing primary drying on the dried materials to obtain first dried materials; performing hot air separation on the first dried materials to respectively obtain heavy substances and light substances; performing X-ray separation on the heavy substances to respectively obtain organic substances and inert substances; jointly performing secondary drying on the light substances and the organic substances to obtain second dried materials; sequentially performing baking, cooling, primary crushing and primary screening on the second dried materials to respectively obtain oversize materials and undersize materials; performing secondary crushing and secondary screening on the undersize materials to obtain quality-improved biomass powder.

Description

Technical Field

[0001] The present invention relates to the technical field of solid waste treatment, and in particular to a process for thermally sorting and upgrading domestic waste and upgraded biomass powder obtained thereby. Background Art

[0002] Traditional methods of domestic waste treatment mainly include landfill and incineration. Although the landfill method has a low cost, it occupies a large amount of land resources for a long time, and there is a risk of leachate from garbage contaminating groundwater and soil. The incineration method can effectively reduce the volume of garbage, but dioxins and other harmful substances may be produced in the process, posing a threat to the environment and human health. In addition, these two traditional methods cannot achieve the resource utilization of garbage, resulting in a huge waste of resources. Therefore, exploring more efficient and environmentally friendly domestic waste sorting and treatment technologies to achieve the resource utilization, reduction and harmlessness of garbage is a key issue that needs to be urgently addressed in the current field of solid waste treatment technology.

[0003] In view of the fact that most domestic waste is collected and disposed of in a naturally mixed manner, in order to solve the above problems, thermal sorting technology has gradually become a research hotspot in recent years, especially the introduction of pyrolysis and baking technologies, which provide new ideas for the efficient treatment of domestic waste. Thermal sorting technology mainly uses a series of process flows such as heating, drying, and screening to effectively separate and classify mixed waste by utilizing the differences in physical properties between different substances; at the same time, thermal sorting technology can effectively destroy the structure of organic matter in the waste through high temperature, reduce the moisture content, increase the calorific value, and promote the separation of inert matter and organic matter, laying the foundation for subsequent resource utilization.

[0004] At present, there are already some technical solutions for the thermal sorting and quality improvement of domestic waste, but most of them have disadvantages such as low sorting accuracy, high energy consumption, and complex operation. For example, some sorting methods can only separate some recyclables in the waste, and the removal effects on organic matters and other impurities are not good (such as an automatic sorting device for recyclable domestic waste disclosed in CN202410204718.6, a domestic waste automatic sorting system disclosed in CN201910708528.7, and a domestic waste sorting device with a closed domestic waste storage disclosed in CN201710202688.5). In addition, although some methods can achieve higher sorting effects, they are difficult to be popularized and used due to high equipment investment costs, large operating energy consumption, etc. (such as a domestic waste pretreatment system based on high-pressure extrusion disclosed in CN201710043977.5, a system and method for treating domestic waste disclosed in CN201710154378.0, a system and method for treating domestic waste disclosed in CN201611192907.8, and a method for applying microwave hydrothermal method to the disposal of domestic waste incineration fly ash disclosed in CN201610472920.2). Finally, there are also some methods that directly apply heat treatment technology to untreated mixed domestic waste, resulting in problems such as high energy consumption, unstable treatment effects, and difficult control of product quality (such as a low-energy consumption domestic waste high-pressure extrusion dry-wet separation device and method disclosed in CN201710044253.2), etc.

[0005] Therefore, the current waste treatment methods often have several problems: 1. It is difficult to fully crush the waste, and due to the high water content of the waste, it is easy to adhere to the inner wall of the crusher, making it difficult for some waste to be crushed again; 2. The composition of domestic waste is complex, with a large amount of plastics and a lot of organic matters. The existing sorting methods are difficult to fully separate various different substances, and it is easy to cause plastics and organic matters to be discharged into the environment again, causing pollution; 3. A large amount of landfill leachate is generated, and the landfill leachate has high COD and BOD contents, and the cycle for removing water is long and the efficiency is low; 4. After the waste is dewatered, it is generally dried by hot air, and the obtained material is then baked or pyrolyzed for resource utilization. However, the hot air drying method is not sufficient, and the material entering the baking device or pyrolysis device still has a certain water content, resulting in insufficient baking and serious adhesion of the internal waste; 5. The product yield obtained by the existing waste baking or pyrolysis technology is low, the energy loss is large, the energy consumption is high, and the problem of dioxin cannot be completely solved.

[0006] In view of this, the present invention is specifically proposed. Summary of the Invention

[0007] In view of the deficiencies of the prior art, the purpose of the present invention is to provide a process method for thermal sorting and upgrading of domestic waste and the upgraded biomass powder obtained therefrom. The process method is a domestic waste thermal sorting and upgrading process method that integrates pretreatment, efficient separation and deep upgrading. Through multiple processes such as coarse crushing, ripening and dehydration, drying, primary drying, hot air separation, X-ray separation, secondary drying, baking, cooling, crushing and screening of domestic waste, finally, high-value upgraded biomass powder is obtained. The present invention aims to achieve the effective separation and upgrading of each component in domestic waste through a series of scientific and reasonable process steps, especially for the organic component, to improve its utilization value as a fuel or raw material through deep treatment, and at the same time reduce the negative impact of inert substances on the subsequent treatment process. It not only improves the sorting efficiency, but also effectively solves the problems existing in the traditional treatment methods, has the characteristics of simple operation and low energy consumption, and has good economic and environmental protection in practical applications. The process method of the present invention prepares upgraded biomass powder by baking domestic waste, improves the fuel characteristics, obtains upgraded biomass powder with high calorific value, the energy is more concentrated, and the energy yield is high, realizing the full resource utilization of domestic waste and no dioxin emission in environmental protection.

[0008] In order to achieve the above object of the present invention, the following technical solutions are specifically adopted:

[0009] In the first aspect, the present invention provides a process method for thermal sorting and upgrading of domestic waste, and the process method includes the following steps:

[0010] The crushed material is subjected to ripening and dehydration, and after the leachate flows out, it is dried to obtain a dried material;

[0011] The dried material is subjected to primary drying to obtain a first dried material;

[0012] The first dried material is subjected to hot air separation to obtain heavy matter and light matter respectively;

[0013] The heavy matter is subjected to magnetic separation, vortex separation, color separation and X-ray separation to obtain magnetic metal (iron), non-magnetic metal (copper, aluminum, etc.), glass, organic matter and inert matter respectively;

[0014] The light matter and the organic matter are jointly subjected to secondary drying to obtain a second dried material;

[0015] The second dried material is successively subjected to baking, cooling, primary crushing and primary screening to obtain oversize and undersize respectively;

[0016] The undersize is subjected to secondary crushing and secondary screening to obtain upgraded biomass powder;

[0017] The inert residue obtained by X-ray separation is made into sand and gravel by a sand making machine.

[0018] In the present invention, through the above process steps of thermal sorting and upgrading of domestic waste, the domestic waste is recycled and converted into upgraded biomass powder with high calorific value and high quality, which is convenient for storage and transportation, enriches the process route of backend treatment, and realizes the reduction, harmlessness and resource treatment of domestic waste. Moreover, the method can prepare upgraded biomass powder with uniform composition, high purity and high energy density by upgrading and increasing the efficiency of domestic waste at low cost and on a large scale. No dioxin is generated during the conversion process, solving the problem of dioxin treatment in the traditional domestic waste incineration treatment method. At the same time, the amount of flue gas generated in this method is small, the amount of dust carried by the flue gas is low, and the pollution to the environment is small.

[0019] Preferably, the specific steps of the coarse crushing include:

[0020] The domestic waste is fed into a coarse crusher through a grab bucket or a conveyor for coarse crushing. The crushed materials are screened to obtain crushed materials with a particle size ≤ 100 mm and crushed materials with a particle size > 100 mm. The crushed materials with a particle size > 100 mm are returned to the coarse crusher for further coarse crushing and screening until the particle size of the obtained materials is ≤ 100 mm.

[0021] Preferably, the coarse crusher is a low-speed coarse crusher. There are two hydraulically or motor-driven rotors arranged in the crushing chamber of the low-speed coarse crusher; cutter heads are fixed on the shafts of the two hydraulically or motor-driven rotors; double-row self-aligning roller bearings are arranged at the fixed ends of the two hydraulically driven rotors, and two thrust self-aligning roller bearings are arranged at the follower ends of the two hydraulically driven rotors.

[0022] In the present invention, the above configuration of the low-speed coarse crusher can not only enable the rotor to withstand tangential and radial stresses, but also enable the rotor to eliminate axial stress when encountering flexible and hard materials that are difficult to break or cannot be broken, protecting the blades / cutter shafts and the supporting / transmission bearings from damage. The crushing of domestic waste is realized through the comprehensive effect of tearing, shearing and extrusion, thereby significantly improving the crushing efficiency, improving the crushing effect and reducing the number of repeated cycle coarse crushings.

[0023] Preferably, the two hydraulically driven rotors include a first hydraulically driven rotor and a second hydraulically driven rotor; wherein, the rotation directions of the first hydraulically driven rotor and the second hydraulically driven rotor are opposite, and the rotational speed of the first hydraulically driven rotor is 8 - 50 r / min, for example, it can be 8 r / min, 10 r / min, 15 r / min, 20 r / min, 25 r / min, 30 r / min, 35 r / min, 40 r / min, 45 r / min, 50 r / min, etc., and the rotational speed of the second hydraulically driven rotor is 10 - 50 r / min, for example, it can be 10 r / min, 15 r / min, 20 r / min, 25 r / min, 30 r / min, 35 r / min, 40 r / min, 45 r / min, 50 r / min, etc.; the rotational speeds of the first hydraulically driven rotor and the second hydraulically driven rotor are different, so as to tear the material.

[0024] Preferably, the cutter heads fixed on the shafts of the two hydraulically driven rotors include: moving cutters opposite to each other in pairs, and stationary cutters in the middle at equal intervals between each group of adjacent moving cutters.

[0025] Preferably, a screen is provided at the bottom of the coarse crusher, and the aperture of the screen holes of the screen is 100 mm.

[0026] Preferably, the ripening temperature is 40 - 50 °C, for example, it can be 40 °C, 42 °C, 44 °C, 46 °C, 48 °C, 50 °C, etc., and the ripening time is 4 - 9 days, for example, it can be 4 days, 5 days, 6 days, 7 days, 8 days, 9 days, etc.

[0027] Preferably, the specific steps of the ripening include:

[0028] Transfer the crushed material to the garbage storage tank, conduct the first ventilation on the 1st - 3rd day, and ensure that the oxygen content in the air flow is 15 - 18%, and the ventilation rate is 0.2 - 0.3 L·kg -1 DM·min -1 , and the temperature of the air flow is 25 - 28 °C; after the end of the first ventilation, turn the material, conduct the second ventilation on the 3rd - 9th day, and ensure that the oxygen content in the air flow is 18 - 20%, and the ventilation rate is 0.3 - 0.4 L·kg -1 DM·min -1 , and the temperature of the air flow is 22 - 25 °C.

[0029] In the present invention, by carrying out ripening and dehydration under the above - mentioned specific conditions of oxygen content and ventilation rate, it is ensured that at a lower ripening temperature, the leachate is accelerated to flow out from the crushed garbage material, and it can also ensure that the leachate flows out more fully, thereby significantly improving the ripening efficiency and reducing the subsequent drying difficulty.

[0030] Preferably, the drying includes heat drying and / or light drying.

[0031] Preferably, the heat drying is carried out through heating pipes arranged at the bottom of the garbage storage tank, and the heating pipes are filled with water vapor and / or hot water.

[0032] Preferably, the flow rate of the water vapor and / or hot water in the heating pipes keeps the temperature in the storage tank at 40-80 °C, such as 40 °C, 45 °C, 50 °C, 55 °C, 60 °C, 65 °C, 70 °C, 75 °C, 80 °C, etc.

[0033] In the present invention, when controlling the temperature by using the water vapor or hot water pipes for heat exchange with the waste heat at the back end, the flow rate of the water vapor or hot water is regulated to control the temperature.

[0034] Preferably, the light drying includes: spraying the hydrogel solution into the garbage storage tank to form a hydrogel film on the surface of the crushed material, and performing light irradiation under sunlight to evaporate the solution in the garbage leachate to complete the drying of the garbage.

[0035] In the present invention, when using light drying, a hydrogel film is formed on the surface of the crushed material. This hydrogel film can absorb and retain the moisture between the garbage, and can quickly form a hydrogel-vapor interface under the drive of light irradiation, significantly improving the evaporation efficiency through light evaporation, and at the same time achieving the purpose of low-energy consumption and high-speed drying of the garbage leachate.

[0036] Preferably, the thickness of the hydrogel film is 0.1-1 mm, such as 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, etc.

[0037] Preferably, the hydrogel film includes a hydrophilic hydrogel matrix and a photothermal material doped in the hydrophilic hydrogel matrix; wherein, the doping amount of the photothermal material accounts for 0.5-5% of the total mass of the hydrogel film, such as 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, etc.

[0038] In the present invention, the hydrogel film is based on a hydrophilic hydrogel, and a certain amount of photothermal material is doped therein. The hydrophilicity of the hydrophilic hydrogel is used to improve the water adsorption, and the loading of the photothermal material is used to provide energy for the conversion of liquid water into gaseous water molecules, so as to further improve the evaporation rate of water, making the drying of the garbage controllable and sufficient.

[0039] Preferably, the hydrophilic hydrogel matrix comprises any one or a combination of at least two of polyvinyl alcohol, polyethylene glycol, sodium polyacrylate, sodium alginate, sodium carboxymethyl cellulose, or chitosan.

[0040] Preferably, the photothermal material comprises any one or a combination of at least two of graphene, carbon nanotubes, graphite powder, or carbon black.

[0041] Preferably, the specific steps of the primary drying include:

[0042] Transfer the dried material to a primary dryer for drying to obtain a first dried material; wherein, the moisture content of the hydrophilic material in the first dried material is reduced to less than 30%, for example, it can be 30%, 28%, 26%, 24%, 22%, 20%, 18%, 16%, 14%, 12%, 10%, etc., and the moisture content of the hydrophobic material in the first dried material is reduced to less than 5%, for example, it can be 5%, 4%, 3%, 2%, 1%, etc.

[0043] Among them, the hydrophilic material comprises any one or a combination of at least two of paper products, textile products, or kitchen waste (such as melon rinds, fruit peels, leftover rice, leftover dishes, etc.); the hydrophobic material comprises any one or a combination of at least two of plastics, foams, metals, glasses, ceramic chips, or stones.

[0044] In the present invention, the primary dryer is an indirect heating heat conduction dryer, including a paddle dryer, a horizontal disk dryer, a steam tube rotary dryer, etc.; the parameters of the primary dryer include: the heating medium is steam at 150 - 200 °C, for example, it can be 150 °C, 160 °C, 170 °C, 180 °C, 190 °C, 200 °C, etc.; the discharge temperature of the primary dryer is 80 - 100 °C, for example, it can be 80 °C, 85 °C, 90 °C, 95 °C, 100 °C, etc.

[0045] Preferably, the light substances comprise any one or a combination of at least two of plastics, paper products, textile products, or foam products; and / or, the heavy substances comprise any one or a combination of at least two of kitchen waste such as melon rinds, fruit peels, leftover rice, and leftover dishes (such as melon rinds, fruit peels, leftover rice, leftover dishes, etc.), bones, metals, glasses, ceramic chips, woods, or stones.

[0046] In the present invention, due to the certain density difference between the light substances and the heavy substances, the light substances and the heavy substances can be separated by adjusting the wind speed, and the air separation process is all completed in a moving air flow field; the loose materials are separated by volume and mass under the combined action of their own gravity, inertia, and air flow drag force; the materials with different densities obtain different types of final products under the action of the air flow.

[0047] Preferably, a horizontal air separator is used for the air separation.

[0048] Preferably, the air temperature of the horizontal air classifier is 100-150 °C, for example, it can be 100 °C, 110 °C, 120 °C, 130 °C, 140 °C, 150 °C.

[0049] Preferably, the air direction of the air separation is 10-20°, for example, it can be 10°, 11°, 12°, 13°, 14°, 15°, 16°, 17°, 18°, 19°, 20°, etc., and the air speed of the air separation is 8-20 m / s, for example, it can be 8 m / s, 10 m / s, 12 m / s, 14 m / s, 16 m / s, 18 m / s, 20 m / s, etc.

[0050] Preferably, the X-ray separator includes two electron X-ray sources, a strong one and a weak one, and independent sensors with two kinds of sensitivities corresponding thereto; the organic matters include any one or a combination of at least two of plastics, vegetable leaves, melon rinds, fruit peels, bones, papers or bamboo and wood; and / or, the inert matters include any one or a combination of at least two of porcelain chips, sandy soil or stones.

[0051] In the present invention, the heavy matters are subjected to X-ray separation, and are separated according to different density images of the materials to obtain organic matters and inert matters respectively; in addition, the light matters and the organic matters selected by X-ray are simultaneously subjected to secondary drying, because after primary drying, there is still a small amount of moisture in the materials, and the moisture in the materials is further reduced through secondary drying to facilitate the baking of the materials.

[0052] Preferably, the moisture content of the second dried material is 5-8%, for example, it can be 5%, 6%, 7%, 8%, etc.

[0053] Preferably, the temperature of the second dried material is 100-120 °C, for example, it can be 100 °C, 105 °C, 110 °C, 115 °C, 120 °C, etc.

[0054] Preferably, the secondary drying uses a direct gas-contact dryer, including any one of a multi-layer belt dryer, a rotary drum dryer or a fluidized bed dryer.

[0055] Preferably, the heat source for the secondary drying is hot air and / or hot flue gas, and the temperature of the hot air and / or hot flue gas is 180-350 °C, for example, it can be 180 °C, 190 °C, 200 °C, 210 °C, 220 °C, 230 °C, 240 °C, 250 °C, 260 °C, 270 °C, 280 °C, 290 °C, 300 °C, 310 °C, 320 °C, 330 °C, 340 °C, 350 °C, etc.

[0056] Preferably, the baking temperature is 210 - 250 °C, such as 210 °C, 220 °C, 230 °C, 240 °C, 250 °C, etc., and the baking time is 20 - 40 min, such as 20 min, 25 min, 30 min, 35 min, 40 min, etc.

[0057] Preferably, a rotary roaster is used for the baking.

[0058] Preferably, the baking heat carrier is recycled baking gas, and the temperature of the recycled baking gas is 250 - 300 °C, such as 250 °C, 260 °C, 270 °C, 280 °C, 290 °C, 300 °C, etc.

[0059] Preferably, a hammer crusher is used for the primary crushing.

[0060] In the present invention, a hammer crusher is used for the primary crushing. The hammer crusher applies an impact force to the material when the rotating hammer heads move at high speed, causing it to break; it mainly consists of a casing, a rotor, hammer heads, a sieve plate, etc. This crusher has a simple structure, convenient operation, and can efficiently complete the crushing process.

[0061] Preferably, the particle size of the oversize material > 5 mm, such as 5.1 mm, 5.5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, etc., and the particle size of the undersize material ≤ 5 mm, such as 5 mm, 4 mm, 3 mm, 2 mm, 1 mm, 0.5 mm, etc.

[0062] Preferably, the main processes of the primary crushing and primary screening include:

[0063] (a) Feeding: The material enters the interior of the crusher through the feed inlet, and the size of the feed inlet is adapted to the specifications and output of the crusher;

[0064] (b) High-speed rotation: The rotor inside the crusher rotates at high speed. There are multiple hammer heads on the rotor, and these hammer heads have a large linear velocity due to the high-speed rotation;

[0065] (c) Impact crushing: After the material enters the crusher, it is impacted by the high-speed rotating hammer heads and thus broken. The impact force is the main force for crushing and can effectively break the material;

[0066] (d) Grinding effect: In addition to impact crushing, the material in the crusher is also subject to a grinding effect because the material will rub and collide with the inner wall of the casing, the sieve plate, and the hammer heads on the rotor during the crushing process;

[0067] (e)Particle size screening: The crushed material passes through the sieve plate. There are sieve holes of a certain size on the sieve plate. The material larger than the sieve holes will be left on the sieve plate for further crushing, while the material smaller than the sieve holes will pass through the sieve plate and be discharged as the finished product;

[0068] (f)Discharging: The finished product material is discharged from the discharge port. The size of the discharge port can be adjusted to control the size of the finished product material. Unqualified large particle materials may re-enter the crusher for re-crushing.

[0069] Preferably, in step (b), the rotational speed of the rotor inside the crusher is 750 - 1500 rpm, for example, it can be 750 rpm, 800 rpm, 850 rpm, 900 rpm, 1000 rpm, 1100 rpm, 1200 rpm, 1300 rpm, 1400 rpm, 1500 rpm, etc. The linear velocity of the hammer head is 25 - 70 m / s, for example, it can be 25 m / s, 30 m / s, 35 m / s, 40 m / s, 45 m / s, 50 m / s, 55 m / s, 60 m / s, 65 m / s, 70 m / s, etc.

[0070] Preferably, in step (c), the impact force of the hammer head is 300 - 500 N, for example, it can be 300 N, 350 N, 400 N, 450 N, 500 N, etc.

[0071] Preferably, in step (e), the particle size of the oversize material remaining on the sieve plate > 5 mm, for example, it can be 5.1 mm, 5.5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, etc.; the particle size of the undersize material discharged through the sieve plate ≤ 5 mm, for example, it can be 5 mm, 4 mm, 3 mm, 2 mm, 1 mm, 0.5 mm, etc.

[0072] Preferably, the process method further includes the following steps: After separating the metal from the oversize material through eddy current separation and magnetic separation, coking materials are obtained; returning the coking materials to the baking step for re-baking and / or returning the coking materials to the primary crushing step for re-crushing.

[0073] Among them, during eddy current separation, the materials are sorted and classified by an eddy current separator. When the eddy current separator works, a high-frequency alternating strong magnetic field will occur on the outer surface of the sorting roller. When the metal enters the strong magnetic field separation area, eddy currents will be induced inside the metal block. The magnetic field generated by this eddy current is opposite to the direction of the original magnetic field, and there is a repulsive force. The effect of this repulsive force can throw the metal block forward to achieve separation. Among them, magnetic separation uses the characteristics of whether different materials have magnetism. Through a magnetic separator, the magnetic useful materials can be extracted from the non-magnetic materials to achieve the purpose of separating the two.

[0074] Preferably, the secondary crushing is carried out by a five-roll differential grinding machine.

[0075] In the present invention, the secondary crushing is carried out by a five-roll differential grinding machine, which can further grind the material to obtain a powder with a particle size meeting the requirements. The differential grinding machine includes a frame, a differential roll group, a cooling and forming roll group, and a temperature control component. The differential roll group includes a low-speed roll, a medium-speed roll, and a high-speed roll, and a gear group for driving the differential rolls to rotate. The cooling and forming roll group includes a low-speed cooling roll, a high-speed cooling roll, and a gear for driving them to rotate. The temperature control component is a high-pressure and high-temperature water temperature machine, a heating pipeline, a refrigerating machine, and a cooling pipeline. Thus, the temperature control component can control the surface temperature of the cooling rolls and the differential rolls. Using this five-roll machine can not only fully grind the material, but also reduce the influence of temperature on the grinding effect in cooperation with the temperature control component.

[0076] Preferably, the differential grinding machine includes a differential roll group; wherein, the differential roll group includes a low-speed roll, a medium-speed roll, and a high-speed roll; the rotation speed ratio of the low-speed roll, the medium-speed roll, and the high-speed roll is 1:(3 - 5):(7 - 9); the rotation speed of the low-speed roll is 15 - 30 rpm.

[0077] Preferably, the differential grinding machine includes a cooling and forming roll group; wherein, the cooling and forming roll group includes a low-speed cooling roll and a high-speed cooling roll; the rotation speed ratio of the low-speed cooling roll and the high-speed cooling roll is 1:(1.14 - 1.19); the rotation speed of the low-speed cooling roll is 20 - 30 rpm; the temperatures of the low-speed cooling roll and the high-speed cooling roll are independently 10 - 20 °C.

[0078] In a second aspect, the present invention provides a quality-improved biomass powder, which is prepared by the process method of thermal sorting and quality improvement of domestic waste as described in the first aspect.

[0079] Preferably, the particle size of the quality-improved biomass powder is 500 - 899 μm.

[0080] Preferably, the specific surface area of the quality-improved biomass powder is 158 - 242 m 2 / g.

[0081] Preferably, the total moisture content of the quality-improved biomass powder is ≤ 3%.

[0082] Preferably, the ash content of the quality-improved biomass powder is below 15%.

[0083] Preferably, the energy density of the quality-improved biomass powder is 12.5 - 30 MJ / kg.

[0084] Preferably, the gasification time of the quality-improved biomass powder when completely gasified at a temperature of 1300 °C is < 7 s.

[0085] Compared with the prior art, the present invention has the following beneficial effects:

[0086] (1) The process method of the present invention is a domestic waste thermal sorting and upgrading process method that integrates pretreatment, efficient separation, and deep upgrading. Through multiple processes such as coarse crushing, ripening and dehydration, drying, primary drying, hot air separation, X-ray separation, secondary drying, baking, cooling, crushing, and screening of domestic waste, high-value-added upgraded biomass powder is finally obtained.

[0087] (2) The process method of the present invention realizes the effective separation and upgrading of each component in domestic waste. Especially for the organic component, its utilization value as fuel or raw material is improved through deep treatment, while reducing the negative impact of inert substances on the subsequent treatment process. It not only improves the sorting efficiency but also effectively solves the problems existing in traditional treatment methods, and has the characteristics of simple operation and low energy consumption.

[0088] (3) The present invention realizes the resource utilization of domestic waste by performing low-temperature baking on domestic waste, converting it into high-calorific value and high-quality upgraded biomass powder, which is convenient for storage and transportation, enriches the backend treatment process route, and realizes the reduction, harmlessness, and resource utilization of domestic waste; the process method can convert domestic waste into high-quality upgraded biomass powder at low cost and on a large scale, and no dioxin is generated during the conversion process, solving the problem of dioxin treatment in traditional domestic waste incineration treatment methods; moreover, the flue gas volume generated by the process method of the present invention is small, the dust volume carried by the flue gas is low, and the environmental pollution is small. Description of the Drawings

[0089] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0090] Figure 1 It is a flowchart of the process method for the thermal sorting and upgrading of domestic waste according to the present invention. Detailed Embodiments

[0091] Unless otherwise defined herein, scientific and technical terms used in conjunction with the present invention shall have the meanings commonly understood by those of ordinary skill in the art. The meanings and scopes of the terms should be clear. However, in any case of potential ambiguity, the definitions provided herein shall prevail over any dictionary or extrinsic definition. In this application, unless otherwise specified, the use of "or" means "and / or". In addition, the use of the term "including" and other forms is non-restrictive.

[0092] It should be noted that specific details are set forth in the following description to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar generalizations without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0093] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0094] The present invention will be further described below through embodiments. Unless otherwise specified, the materials in the embodiments are prepared according to existing methods or directly purchased from the market.

[0095] Embodiment 1

[0096] This embodiment provides a process method for thermal sorting and quality improvement of domestic waste. As Figure 1 shown, the process method includes the following steps:

[0097] S1. Coarse crushing:

[0098] The domestic waste is fed into the coarse crusher through a grab for coarse crushing. After screening, crushed materials with a particle size ≤ 100 mm and crushed materials with a particle size > 100 mm are obtained respectively. The crushed materials with a particle size > 100 mm are returned to the coarse crusher for re - coarse crushing and screening. The crushing needs to be repeated 3 times, and the particle size of the materials obtained by coarse crushing is all ≤ 100 mm.

[0099] Among them, the coarse crusher is a low - speed coarse crusher. Two hydraulically driven rotors are arranged in the crushing chamber of the low - speed coarse crusher; cutter heads are fixed on the shafts of the two hydraulically driven rotors; double - row self - aligning roller bearings are configured at the fixed ends of the two hydraulically driven rotors, and two thrust self - aligning roller bearings are configured at the follower ends of the two hydraulically driven rotors.

[0100] Among them, the two hydraulic-driven rotors include a first hydraulic-driven rotor and a second hydraulic-driven rotor; the rotation directions of the first hydraulic-driven rotor and the second hydraulic-driven rotor are opposite, and the rotation speed of the first hydraulic-driven rotor is 50 r / min, and the rotation speed of the second hydraulic-driven rotor is 10 r / min; the rotation speeds of the first hydraulic-driven rotor and the second hydraulic-driven rotor are different, so as to tear the material; the cutter heads fixed on the shafts of the two hydraulic-driven rotors include: 5 groups of moving cutters opposite to each other in pairs, and static cutters in the middle at equal intervals between each adjacent pair of moving cutters. A screen is provided at the bottom of the coarse crusher, and the aperture of the screen holes of the screen is 100 mm.

[0101] S2. Ripening dehydration - drying:

[0102] (a) Transfer the crushed material to the garbage storage tank, and co-ripen and dehydrate for 6 days at 45°C to allow the leachate to flow out of the garbage material; among them, the first ventilation is carried out on the 1st - 2nd day, and the oxygen content in the air flow is ensured to be 16%, and the ventilation rate is 0.25 L·kg -1 DM·min -1 , and the temperature of the air flow is 26°C; after the first ventilation ends, turn the material, and the second ventilation is carried out on the 3rd - 6th day, and the oxygen content in the air flow is ensured to be 19%, and the ventilation rate is 0.35 L·kg -1 DM·min -1 , and the temperature of the air flow is 23°C;

[0103] (b) Spray the hydrogel solution into the garbage storage tank to form a hydrogel film with an average thickness of 0.5 mm on the surface of the crushed material (the hydrogel film includes a polyvinyl alcohol matrix and graphene doped in the polyvinyl alcohol matrix; among them, the doping amount of graphene is 2%), and carry out light irradiation for 60 min under sunlight at 25°C to evaporate the solution in the garbage leachate, complete the drying of the garbage, and obtain a dried material with a water content of 38%.

[0104] S3. Primary drying:

[0105] Transfer the dried material to a primary dryer for primary drying to obtain a first dried material; the moisture content of the hydrophilic materials in the first dried material is reduced to 20%, and the moisture content of the hydrophobic materials is reduced to 2%; the hydrophilic materials include kitchen waste such as paper products, textile products, melon rinds, fruit peels, and leftovers; the hydrophobic materials include plastics, foams, metals, glasses, porcelain chips, stones, etc.;

[0106] Among them, the parameters of the primary drying include: using a paddle dryer, the heating medium is steam at 200°C, the discharge temperature of the primary dryer is 100°C, and the heat transfer area of the paddle drying is 280 m 2, the power of the paddle dryer is 45 kW, the rotational speed of the paddles is 12 r / min, and the effective volume of the paddle dryer is 12.8 m 3 .

[0107] S4. Hot air separation by air classifier:

[0108] The first dried material is separated by hot air using a horizontal air classifier to obtain heavy materials and light materials respectively; the light materials include any one or at least two combinations of plastics, paper products, textile products or foam products; and / or, the heavy materials include any one or at least two combinations of kitchen waste such as melon rinds, fruit peels and leftovers, bones, metals, glass, porcelain chips, wood or stones;

[0109] Among them, the inlet shape of the horizontal air classifier is rectangular, the height of the inlet is 500 mm, the height of the center position of the inlet is 1550 mm, and the air temperature is 150°C; the direction of the air separation is 15°, and the air speed is 10 m / s.

[0110] S5. X-ray separation by X-ray separator:

[0111] The heavy materials are separated by X-ray using an X-ray separator to obtain organic materials and inert materials respectively. The X-ray separator includes two electron X-ray sources with strong and weak intensities and corresponding independent sensors with two sensitivities; the organic materials include any one or at least two combinations of plastics, vegetable leaves, melon rinds, fruit peels, bones, paper or bamboo and wood; the inert materials include any one or at least two combinations of porcelain chips, sandy soil or stones.

[0112] S6. Secondary drying:

[0113] The light materials obtained in S4 and the organic materials obtained in S5 are mixed and jointly dried by a multi-layer belt dryer for secondary drying to obtain a second dried material with a water content of 5%, and the temperature of the second dried material is 120°C;

[0114] Among them, the heat source for the secondary drying is hot air, the temperature of the hot air is 350°C, and the intensity of the secondary drying is 10 kg water / m 2 ·h; the conveyor belt for the secondary drying is a plate conveyor belt; among them, the plate conveyor belt is made of a stainless steel thin plate with a thickness of 1 mm, and 1.5 mm×6 mm long strip-shaped punching holes are provided on the plate conveyor belt, and the hole opening rate is 20%; the width of the conveyor belt is 2.0 m and the length is 30 m; the thickness of the material layer formed by the light materials and the organic materials is 50 mm, and the load of the material layer is 500 kg / m 2 ; the total resistance of the conveyor belt and the material layer is 350 Pa; the cross-flow velocity of the drying medium in the multi-layer belt dryer is 1.0 m / s.

[0115] S7. Baking:

[0116] Transfer the second dried material to a baking device and bake it at 230 °C for 40 min to obtain a baked material; wherein, the baking is carried out using a rotary drum baking machine; the baking heat carrier is recycled baking gas, and the temperature of the recycled baking gas is 300 °C.

[0117] S8. Cooling

[0118] Cool the baked material at a cooling rate of 5 °C / min to 25 °C and cool it at this temperature for 40 min to catalyze the material and obtain a cooled baked material.

[0119] S9. Primary crushing and primary screening:

[0120] Carry out primary crushing and primary screening on the cooled baked material in sequence, ensuring that the average processing rate of this process is 80 t / h; wherein, the process of primary crushing and primary screening includes:

[0121] (a) Feeding: The material enters the interior of the crusher through the feeding port, and the size of the feeding port is adapted to the specifications and output of the crusher;

[0122] (b) High-speed rotation: The rotor inside the crusher rotates at a high speed. There are multiple hammers on the rotor, and these hammers have a large linear velocity due to high-speed rotation; wherein, the rotational speed of the rotor inside the crusher is 1000 rpm, and the linear velocity of the hammers is 70 m / s;

[0123] (c) Impact crushing: After the material enters the crusher, it is impacted by the high-speed rotating hammers and thus broken. The impact force is the main force for crushing and can effectively break the material; the impact force of the hammers is 450 N;

[0124] (d) Grinding effect: In addition to impact crushing, the material in the crusher will also be subject to a grinding effect because the material will rub and collide with the inner wall of the machine shell, the screen plate, and the hammers on the rotor during the crushing process;

[0125] (e) Particle size screening: The crushed material passes through the screen plate. There are screen holes of a certain size on the screen plate. Materials larger than the screen holes will be left on the screen plate for further crushing, and materials smaller than the screen holes will pass through the screen plate and be discharged as finished products; wherein, the particle size of the oversize material left on the screen plate > 5 mm (accounting for 25%); the particle size of the undersize material discharged through the screen plate ≤ 5 mm (accounting for 75%).

[0126] (f) Discharge: The finished product material is discharged from the discharge port, and the size of the discharge port can be adjusted to control the size of the finished product material. Unqualified large particle materials may re-enter the crusher for re-crushing.

[0127] S10, Secondary crushing and secondary screening:

[0128] After subjecting the undersize material to secondary crushing using a five-roll differential grinder, secondary screening is then carried out to obtain upgraded biomass powder.

[0129] Among them, the differential grinder includes a differential roll group; among them, the differential roll group includes a low-speed roll, a medium-speed roll, and a high-speed roll; the speed ratio of the low-speed roll, the medium-speed roll, and the high-speed roll is 1:3:9; the speed of the low-speed roll is 30 rpm; the differential grinder includes a cooling and forming roll group; the cooling and forming roll group includes a low-speed cooling roll and a high-speed cooling roll; the speed ratio of the low-speed cooling roll and the high-speed cooling roll is 1:1.19; the speed of the low-speed cooling roll is 30 rpm; the temperature of the low-speed cooling roll is 12 °C, and the temperature of the high-speed cooling roll is 18 °C.

[0130] Example 2

[0131] This embodiment provides a process method for thermal sorting and upgrading of domestic waste, as Figure 1 shown, the process method includes the following steps:

[0132] S1, Coarse crushing:

[0133] The domestic waste is fed into a coarse crusher through a conveyor for coarse crushing, and the crushed materials with a particle size ≤ 100 mm and the crushed materials with a particle size > 100 mm are obtained through screening. The crushed materials with a particle size > 100 mm are returned to the coarse crusher for re-coarse crushing and screening. The crushing needs to be repeated 5 times until the particle size of the materials obtained by coarse crushing is all ≤ 100 mm.

[0134] Among them, the coarse crusher is a low-speed coarse crusher, and there are two motor-driven rotors arranged in the crushing chamber of the low-speed coarse crusher; knife heads are fixed on the shafts of the two motor-driven rotors; double-row self-aligning roller bearings are configured at the fixed ends of the two motor-driven rotors, and two thrust self-aligning roller bearings are configured at the follower ends of the two motor-driven rotors.

[0135] Among them, the two motor-driven rotors include a first motor-driven rotor and a second motor-driven rotor; the rotation directions of the first motor-driven rotor and the second motor-driven rotor are opposite, and the speed of the first motor-driven rotor is 8 r / min, and the speed of the second motor-driven rotor is 50 r / min; the different speeds of the first motor-driven rotor and the second motor-driven rotor tear the material. The knife heads fixed on the shafts of the two motor-driven rotors include: 5 groups of moving knives opposite to each other in pairs, and static knives in the middle at equal intervals between each group of adjacent moving knives. A screen is provided at the bottom of the coarse crusher, and the aperture of the screen holes of the screen is 100 mm.

[0136] S2. Curing and dehydration - drying:

[0137] (a) Transfer the crushed materials to the garbage storage tank, and co - cure for 9 days at 40°C for dehydration, allowing the leachate to flow out of the garbage materials. Among them, for the first 1 - 3 days, the first ventilation is carried out, and the oxygen content in the air flow is ensured to be 15%, and the ventilation rate is 0.3 L·kg -1 DM·min -1 , and the temperature of the air flow is 28°C. After the first ventilation ends, the materials are turned over. For the 4 - 9 days, the second ventilation is carried out, and the oxygen content in the air flow is ensured to be 18%, and the ventilation rate is 0.4 L·kg -1 DM·min -1 , and the temperature of the air flow is 25°C;

[0138] (b) Spray the hydrogel solution into the garbage storage tank to form a hydrogel film with an average thickness of 0.5 mm on the surface of the crushed materials (the hydrogel film includes a chitosan matrix and carbon nanotubes doped in the chitosan matrix; among them, the doping amount of the carbon nanotubes is 2%). Carry out light irradiation under sunlight at 25°C for 50 min to evaporate the solution in the garbage leachate, complete the drying of the garbage, and obtain dried materials with a water content of 39%.

[0139] S3. Primary drying:

[0140] Transfer the dried materials to a primary dryer for primary drying to obtain the first dried materials. The moisture content of the hydrophilic materials in the first dried materials is reduced to 25%, and the moisture content of the hydrophobic materials is reduced to 3%. The hydrophilic materials include kitchen waste such as paper products, textile products, melon rinds, fruit peels, leftovers, etc.; the hydrophobic materials include plastics, foams, metals, glasses, ceramic chips, stones, etc.;

[0141] The primary dryer is an indirect - heating heat - conduction dryer, and here a horizontal disk dryer is used. The parameters of the primary dryer include: the heating medium is steam at 150°C, and the discharge temperature of the primary dryer is 80°C.

[0142] S4. Hot - air separation by winnowing:

[0143] Use a horizontal winnowing machine to carry out hot - air separation on the first dried materials to obtain heavy substances and light substances respectively. The light substances include any one or at least two combinations of plastics, paper products, textile products, or foam products; and / or, the heavy substances include any one or at least two combinations of kitchen waste such as melon rinds, fruit peels, leftovers, bones, metals, glasses, ceramic chips, woods, or stones;

[0144] Among them, the inlet of the horizontal air classifier is rectangular, with a height of 500 mm and the height of the center position of the inlet is 1550 mm; the air temperature is 100 °C; the air separation direction is 15° and the air velocity is 15 m / s.

[0145] S5. X-ray separation:

[0146] Perform X-ray separation on the heavy substances to obtain organic matter and inert substances respectively. The X-ray separator includes two strong and weak electron X-ray sources and independent sensors with two sensitivities corresponding thereto; the organic matter includes any one or at least two combinations of plastic, vegetable leaves, melon rinds, fruit shells, bones, paper or bamboo and wood; the inert substances include any one or at least two combinations of porcelain chips, sandy soil or stones.

[0147] S6. Secondary drying:

[0148] Mix the light substances obtained in S4 and the organic matter obtained in S5 and jointly perform secondary drying using a rotary drum dryer to obtain a second dried material.

[0149] Among them, the temperature of the second dried material is 100 °C; the drying medium is hot flue gas and the temperature of the hot flue gas is 180 °C.

[0150] S7. Baking:

[0151] Transfer the second dried material to a baking device and bake it at 210 °C for 20 min to obtain a baked material. The baking heat carrier is circulating baking gas and the temperature of the circulating baking gas is 250 °C.

[0152] S8. Cooling

[0153] Cool the baked material, cool it down to 25 °C at a cooling rate of 5 °C / min and cool it at this temperature for 60 min to embrittle the material and obtain a cooled baked material.

[0154] S9. Primary crushing and primary screening:

[0155] Perform primary crushing and primary screening on the cooled baked material in sequence, ensuring that the average processing rate of this process is 50 t / h; among them, the process of primary crushing and primary screening includes:

[0156] (a) Feeding: The material enters the inside of the crusher through the feeding port, and the size of the feeding port is adapted to the specifications and output of the crusher.

[0157] (b)High-speed rotation: The rotor inside the crusher rotates at high speed. There are multiple hammers on the rotor, and these hammers have a relatively large linear velocity due to the high-speed rotation. Among them, the rotational speed of the rotor inside the crusher is 1000 rpm, and the linear velocity of the hammers is 50 m / s.

[0158] (c)Impact crushing: After the material enters the crusher, it is impacted by the hammers rotating at high speed and thus broken. The impact force is the main force for crushing and can effectively crush the material. The impact force of the hammers is 400 N.

[0159] (d)Grinding effect: In addition to impact crushing, the material inside the crusher will also be subject to a grinding effect because the material will rub and collide with the inner wall of the machine shell, the sieve plate, and the hammers on the rotor during the crushing process.

[0160] (e)Particle size screening: The crushed material passes through the sieve plate. There are sieve holes of a certain size on the sieve plate. Materials larger than the sieve holes will be left on the sieve plate for further crushing, while materials smaller than the sieve holes will pass through the sieve plate and be discharged as finished products. Among them, the particle size of the oversize material left on the sieve plate > 5 mm (accounting for 27%); the particle size of the undersize material discharged through the sieve plate ≤ 5 mm (accounting for 73%).

[0161] (f)Discharging: The finished product material is discharged from the discharge port. The size of the discharge port can be adjusted to control the size of the finished product material. Unqualified large-particle materials may re-enter the crusher for re-crushing.

[0162] S10. Secondary crushing and secondary screening:

[0163] The undersize material is subjected to secondary crushing by a five-roll differential grinding machine and then subjected to secondary screening to obtain upgraded biomass powder.

[0164] Among them, the differential grinding machine includes a differential roll group. Among them, the differential roll group includes a low-speed roll, a medium-speed roll, and a high-speed roll. The rotational speed ratio of the low-speed roll, the medium-speed roll, and the high-speed roll is 1:5:8. The rotational speed of the low-speed roll is 25 rpm. The differential grinding machine includes a cooling and forming roll group. The cooling and forming roll group includes a low-speed cooling roll and a high-speed cooling roll. The rotational speed ratio of the low-speed cooling roll and the high-speed cooling roll is 1:1.15. The rotational speed of the low-speed cooling roll is 30 rpm. The temperature of the low-speed cooling roll is 15 °C, and the temperature of the high-speed cooling roll is 19 °C.

[0165] Example 3

[0166] This example provides a process method for thermal sorting and upgrading of domestic waste, as Figure 1 shown. The process method includes the following steps:

[0167] S1. Coarse crushing:

[0168] Domestic waste is fed into the coarse crusher by a grab for coarse crushing. After screening, crushed materials with a particle size ≤ 100 mm and crushed materials with a particle size > 100 mm are obtained respectively. The crushed materials with a particle size > 100 mm are returned to the coarse crusher for re - coarse crushing and screening. The crushing needs to be repeated 3 times until the particle size of the materials obtained by coarse crushing is all ≤ 100 mm;

[0169] Among them, the coarse crusher is a low - speed coarse crusher. There are two hydraulically driven rotors arranged in the crushing chamber of the low - speed coarse crusher; knife heads are fixed on the shafts of the two hydraulically driven rotors; double - row self - aligning roller bearings are configured at the fixed ends of the two hydraulically driven rotors, and two thrust self - aligning roller bearings are configured at the follower ends of the two hydraulically driven rotors;

[0170] Among them, the two hydraulically driven rotors include a first hydraulically driven rotor and a second hydraulically driven rotor; the first hydraulically driven rotor and the second hydraulically driven rotor rotate in opposite directions, and the rotational speed of the first hydraulically driven rotor is 15 r / min, and the rotational speed of the second hydraulically driven rotor is 30 r / min; the knife heads fixed on the shafts of the two hydraulically driven rotors include: 5 groups of moving knives opposite to each other in pairs, and static knives in the middle at equal intervals between each group of adjacent moving knives. A screen is provided at the bottom of the coarse crusher, and the aperture of the screen holes of the screen is 100 mm.

[0171] S2. Ripening dehydration - drying:

[0172] (a) Transfer the crushed materials to the garbage storage tank and co - ripen for 9 days at 40 °C for dehydration to allow leachate to flow out from the garbage materials; among them, the first ventilation is carried out on the 1st - 3rd day, and the oxygen content in the air flow is ensured to be 18%, and the ventilation rate is 0.2 L·kg -1 DM·min -1 , and the temperature of the air flow is 25 °C; after the first ventilation ends, the materials are turned over, and the second ventilation is carried out on the 4th - 9th day, and the oxygen content in the air flow is ensured to be 20%, and the ventilation rate is 0.3 L·kg -1 DM·min -1 , and the temperature of the air flow is 22 °C;

[0173] (b) Spray the hydrogel solution into the garbage storage tank to form a hydrogel film with an average thickness of 0.5 mm on the surface of the crushed materials (the hydrogel film includes a sodium carboxymethylcellulose matrix and graphite powder doped in the sodium carboxymethylcellulose matrix; among them, the doping amount of the graphite powder is 2%). Irradiate under sunlight at 25 °C for 60 min to evaporate the solution in the garbage leachate, complete the drying of the garbage, and obtain dried materials with a water content of 37%.

[0174] S3. Primary drying:

[0175] Transfer the dried material to a paddle dryer for primary drying to obtain a first dried material; the moisture content of the hydrophilic material in the first dried material is reduced to 20%, and the moisture content of the hydrophobic material is reduced to 1%.

[0176] Among them, the parameters of primary drying include: using a steam tube rotary dryer; the heating medium is steam at 180 °C, and the discharge temperature of the primary dryer is 90 °C.

[0177] S4. Hot air separation:

[0178] Separate the first dried material by a horizontal air separator to obtain heavy matter and light matter respectively;

[0179] Among them, the shape of the air inlet of the horizontal air separator is rectangular, the height of the air inlet is 500 mm, the height of the center position of the air inlet is 1550 mm, and the air temperature is 120 °C; the direction of the air separation is 15°, and the air speed is 20 m / s.

[0180] S5. X-ray separation:

[0181] Perform X-ray separation on the heavy matter to obtain organic matter and inert matter respectively. The X-ray separator includes two electron X-ray sources, a strong one and a weak one, and independent sensors with two sensitivities corresponding to them; the organic matter includes any one or at least two combinations of plastics, vegetable leaves, melon rinds, fruit husks, bones, paper or bamboo and wood; the inert matter includes any one or at least two combinations of porcelain chips, sand or stones.

[0182] S6. Secondary drying:

[0183] Mix the light matter obtained in S4 and the organic matter obtained in S5 and jointly perform secondary drying using a fluidized bed dryer to obtain a second dried material, and the moisture content in the second dried material is 7%;

[0184] Among them, the temperature of the second dried material is 110 °C; the heat source for secondary drying is hot flue gas, and the temperature of the hot flue gas is 320 °C.

[0185] S7. Baking:

[0186] Transfer the second dried material to a baking device and bake it at 250 °C for 30 minutes to obtain a baked material. The baking uses a rotary drum baking machine, and the baking heat carrier is circulating baking gas, and the temperature of the circulating baking gas is 280 °C.

[0187] S8. Cooling

[0188] Cool the baked material at a cooling rate of 5 °C / min to 25 °C and cool it at this temperature for 50 min to catalyze the material, obtaining the cooled baked material.

[0189] S9. Primary crushing and primary screening:

[0190] Perform primary crushing and primary screening on the cooled baked material in sequence, ensuring that the average processing rate of this process is 100 t / h; wherein, the process of primary crushing and primary screening includes:

[0191] (a) Feeding: The material enters the interior of the crusher through the feeding port, and the size of the feeding port is adapted to the specifications and output of the crusher;

[0192] (b) High-speed rotation: The rotor inside the crusher rotates at high speed. There are multiple hammers on the rotor, and these hammers have a large linear velocity due to high-speed rotation; wherein, the rotational speed of the rotor inside the crusher is 1500 rpm, and the linear velocity of the hammers is 70 m / s;

[0193] (c) Impact crushing: After the material enters the crusher, it is impacted by the hammers rotating at high speed and thus broken. The impact force is the main force for crushing and can effectively crush the material; the impact force of the hammers is 500 N;

[0194] (d) Grinding effect: In addition to impact crushing, the material in the crusher will also be subject to a grinding effect because the material will rub and collide with the inner wall of the casing, the screen plate, and the hammers on the rotor during the crushing process;

[0195] (e) Particle size screening: The crushed material passes through the screen plate. There are screen holes of a certain size on the screen plate. The material larger than the screen holes will be left on the screen plate for further crushing, and the material smaller than the screen holes will pass through the screen plate and be discharged as the finished product; wherein, the particle size of the oversize material left on the screen plate > 5 mm (accounting for 26%); the particle size of the undersize material discharged through the screen plate ≤ 5 mm (accounting for 74%).

[0196] (f) Discharge: The finished product material is discharged from the discharge port, and the size of the discharge port can be adjusted to control the size of the finished product material. Unqualified large-particle materials may re-enter the crusher for re-crushing.

[0197] S10. Secondary crushing and secondary screening:

[0198] After secondary crushing the undersize material with a five-roll differential grinder, perform secondary screening to obtain the upgraded biomass powder;

[0199] Among them, the differential grinding machine includes a differential roll set; among them, the differential roll set includes a low-speed roll, a medium-speed roll, and a high-speed roll; the rotational speed ratio of the low-speed roll, the medium-speed roll, and the high-speed roll is 1:4:8; the rotational speed of the low-speed roll is 25 rpm; the differential grinding machine includes a cooling and forming roll set; the cooling and forming roll set includes a low-speed cooling roll and a high-speed cooling roll; the rotational speed ratio of the low-speed cooling roll and the high-speed cooling roll is 1:1.18; the rotational speed of the low-speed cooling roll is 30 rpm; the temperature of the low-speed cooling roll is 17 °C, and the temperature of the high-speed cooling roll is 19 °C.

[0200] Example 4

[0201] This example provides a process method for thermal sorting and quality improvement of domestic waste. The difference from Example 1 is that the oversize materials obtained after the first-stage screening in S9 are sequentially subjected to eddy current separation and magnetic separation to separate metals, obtaining coking materials; the coking materials are returned to the step of S7 baking for baking again, and other steps are the same as those in Example 1.

[0202] Example 5

[0203] This example provides a process method for thermal sorting and quality improvement of domestic waste. The difference from Example 1 is that the oversize materials obtained after the first-stage screening in S9 are sequentially subjected to eddy current separation and magnetic separation to separate metals, obtaining coking materials; the coking materials are returned to the step of S9 primary crushing for crushing again, and other steps are the same as those in Example 1.

[0204] Example 6

[0205] This example provides a process method for thermal sorting and quality improvement of domestic waste. The difference from Example 1 is that in step (b) of S2 during the drying process, no hydrogel is added, and the following method is used for drying treatment:

[0206] Heating pipes are arranged at the bottom of the garbage storage tank, steam is introduced into the heating pipes, the flow rate of the steam is set to 0.42 m / s to ensure that the temperature of the garbage storage tank is maintained at 45 ± 2 °C, and at the same time, solar light is used to dry the materials. Under these conditions, it takes at least 24 h of drying to reduce the water content of the dried materials to 38%.

[0207] Example 7

[0208] This example provides a process method for thermal sorting and quality improvement of domestic waste. The difference from Example 1 is that in S1, only one hydraulic drive rotor is provided, and the rotational speed of the hydraulic drive rotor is increased to 60 r / min. The cutter heads fixed on the shafts of the two hydraulic drive rotors include: 10 groups of moving knives opposite to each other in pairs, and static knives in the middle at equal intervals between each group of adjacent moving knives;

[0209] The results show that domestic waste is fed into the coarse crusher through a grab for coarse crushing, and crushed materials with a particle size ≤ 100 mm and crushed materials with a particle size > 100 mm are obtained respectively. The crushed materials with a particle size > 100 mm are returned to the coarse crusher for coarse crushing again. Coarse crushing needs to be repeated 7 times before the particle size of all the crushed materials can be ≤ 100 mm.

[0210] Example 8

[0211] This example provides a process method for thermal sorting and quality improvement of domestic waste. The difference from Example 1 lies in the different steps of ripening and dehydration, which are specifically as follows:

[0212] Transfer the crushed materials to the waste storage tank, and co-ripen and dehydrate at 45 °C for 6 days to allow the leachate to flow out from the waste materials. Among them, the first ventilation is carried out on the 1st - 3rd day, and the oxygen content in the air flow is ensured to be 19%, and the ventilation rate is 0.35 L·kg -1 DM·min -1 , and the temperature of the air flow is 23 °C. After the first ventilation ends, turn the materials. The second ventilation is carried out on the 4th - 6th day, and the oxygen content in the air flow is ensured to be 16%, and the ventilation rate is 0.25 L·kg -1 DM·min -1 , and the temperature of the air flow is 26 °C;

[0213] The results show that after drying in step (b) the same as in Example 1, dried materials with a water content of 42% are obtained.

[0214] Example 9

[0215] This example provides a process method for thermal sorting and quality improvement of domestic waste. The difference from Example 1 is that the steps of primary drying and secondary drying are interchanged, that is, S3 uses a multi-layer belt dryer for primary drying (the process parameters are the same as in Example 1); S6 uses a paddle dryer for secondary drying (the process parameters are the same as in Example 1);

[0216] The results show that the water content of hydrophilic materials in the first dried materials is 32%, and the water content of hydrophobic materials is 7%; the average water content in the second dried materials is 9%.

[0217] Example 10

[0218] This example provides a process method for thermal sorting and quality improvement of domestic waste. The difference from Example 1 is that in S9, the primary crushing no longer uses a hammer crusher, but uses a low-speed coarse crusher for primary crushing in S1 (the process parameters are the same as in Example 1) and then screens through a sieve with a pore size of 5 mm;

[0219] The results show that the content of oversize particles with a particle size > 5 mm remaining on the sieve is as high as 82%, while the content of undersize particles discharged through the sieve is only 18%.

[0220] Example 11

[0221] This example provides a process method for thermal sorting and quality improvement of domestic waste. The difference from Example 1 is that in S10, the differential roller group of the secondary crusher is set differently from that in Example 1. Specifically:

[0222] The differential grinder includes a differential roller group; among them, the differential roller group includes a low-speed roller and a high-speed roller; the speed ratio of the low-speed roller to the high-speed roller is 1:3; the speed of the low-speed roller is 40 rpm; the differential grinder includes a cooling and forming roller group;

[0223] The cooling and forming roller group includes a cooling roller; the speed of the cooling roller is 18 rpm; the temperature of the cooling roller is 15 °C.

[0224] Comparative Example 1

[0225] This comparative example provides a process method for thermal sorting and quality improvement of domestic waste. The difference from Example 1 is that the step of S1 coarse crushing is not carried out, and other settings are the same as those in Example 1.

[0226] Comparative Example 2

[0227] This comparative example provides a process method for thermal sorting and quality improvement of domestic waste. The difference from Example 1 is that the step of S2 (a) ripening and dehydration is not carried out, and the step of (b) drying is directly carried out, and other settings are the same as those in Example 1.

[0228] Comparative Example 3

[0229] This comparative example provides a process method for thermal sorting and quality improvement of domestic waste. The difference from Example 1 is that the step of S2 (b) drying is not carried out. After S1 ripening and dehydration, it is directly filtered through a filter screen, and the obtained wet material is directly subjected to primary drying, and other settings are the same as those in Example 1.

[0230] Comparative Example 4

[0231] This comparative example provides a process method for thermal sorting and quality improvement of domestic waste. The difference from Example 1 is that the step of S3 primary drying is not carried out, and other settings are the same as those in Example 1.

[0232] Comparative Example 5

[0233] This comparative example provides a process method for thermal sorting and quality improvement of domestic waste. The difference from Example 1 is that the step of S6 secondary drying is not carried out, and other settings are the same as those in Example 1.

[0234] Comparative Example 6

[0235] This comparative example provides a process method for thermal sorting and quality improvement of domestic waste. The difference from Example 1 is that the step of S8 cooling is not carried out, and other settings are the same as those in Example 1.

[0236] Comparative Example 7

[0237] This comparative example provides a process method for thermal sorting and quality improvement of domestic waste. The difference from Example 1 is that the steps of primary crushing and primary screening of S9 are not carried out, and other settings are the same as those in Example 1.

[0238] Comparative Example 8

[0239] This comparative example provides a process method for thermal sorting and quality improvement of domestic waste. The difference from Example 1 is that the steps of secondary crushing and secondary screening of S10 are not carried out, and other settings are the same as those in Example 1.

[0240] Test Example 1

[0241] Test samples: The upgraded biomass powder prepared by the process methods provided in Examples 1 to 11, and the upgraded biomass powder prepared by the process methods provided in Comparative Examples 1 to 8;

[0242] The test results are shown in Table 1 below:

[0243] Table 1

[0244]

[0245] As shown in the results of Table 1, the average particle size of the upgraded biomass powder prepared by the process method of the present invention is 500 - 899 μm, the specific surface area is 158 - 242 m 2 / g, the energy density is 12.5 - 30.0 MJ / kg, the ash content is as low as below 15%, the water content is as low as below 3%, and the total yield is above 86.38%. This shows that the process method of the present invention performs low-temperature baking on domestic waste, realizes resource utilization, carbonizes domestic waste, and prepares an upgraded biomass powder with uniform composition and high energy density by improving the quality and efficiency of domestic waste, which can be further used for the preparation of green energy and enriches the subsequent process route.

[0246] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A process for hot sorting and quality improvement of domestic waste, characterized in that: The process comprises the following steps: The domestic waste is roughly crushed to obtain crushed materials with a particle size of ≤100 mm; The crushed material is matured and dehydrated, and dried after the leachate flows out to obtain a dried material; The specific steps of the maturation include: transferring the crushed materials to the garbage storage tank, performing the first ventilation on the 1st to 3rd day, and ensuring that the oxygen content in the wind flow is 15-18% and the ventilation rate is 0.2-0.3 L·kg -1 DM·min -1 , the air temperature is 25~28℃; after the first ventilation, turn the material, and conduct the second ventilation on the 3rd to 9th day, and ensure that the oxygen content in the air flow is 18~20%, and the ventilation rate is 0.3~0.4 L·kg -1 DM·min -1 , the temperature of the wind flow is 22~25℃; Wherein, the drying is light drying; the light drying comprises: spraying a hydrogel solution into a garbage storage tank to form a hydrogel film on the surface of the crushed material, irradiating the solution under sunlight to evaporate the solution in the garbage leachate, and completing the drying of the garbage; the hydrogel film comprises a hydrophilic hydrogel matrix and a photothermal material doped in the hydrophilic hydrogel matrix; wherein the doping amount of the photothermal material accounts for 0.5-5% of the total mass of the hydrogel film; The dried material is subjected to primary drying to obtain a first dried material; The first dried material is subjected to hot air separation to obtain heavy matter and light matter respectively; The heavy substances are subjected to magnetic separation, vortex separation, color separation and X-ray separation to obtain magnetic metals, non-magnetic metals, glass, organic matter and inert matter respectively; The light matter and the organic matter are subjected to secondary drying together to obtain a second dried material; The second dried material is sequentially baked, cooled, first-stage crushed and first-stage screened to obtain an oversize material and an undersize material, respectively; The screened material is subjected to secondary crushing and secondary screening to obtain improved biomass powder; The inert residue obtained by the X-ray separation is processed into sand and gravel by a sand making machine.

2. The process for hot sorting and upgrading of domestic waste according to claim 1 is characterized in that: The specific steps of the coarse crushing include: The domestic garbage is fed into the coarse crusher through a grab bucket or a conveyor for coarse crushing and screening to obtain crushed materials with a particle size ≤100 mm and crushed materials with a particle size >100 mm. The crushed materials with a particle size >100 mm are returned to the coarse crusher for coarse crushing and screening again until the particle size of the obtained materials is ≤100 mm.

3. The process for hot sorting and upgrading of domestic waste according to claim 2 is characterized in that: The coarse crusher is a low-speed coarse crusher, and two hydraulically driven rotors are arranged in the crushing chamber of the low-speed coarse crusher; cutter heads are fixed on the shafts of the two hydraulically driven rotors; double-row self-aligning roller bearings are arranged at the fixed ends of the two hydraulically driven rotors, and two thrust self-aligning roller bearings are arranged at the following ends of the two hydraulically driven rotors.

4. The process for thermal sorting and upgrading of domestic waste according to claim 3 is characterized in that: The two hydraulically driven rotors include a first hydraulically driven rotor and a second hydraulically driven rotor; wherein the first hydraulically driven rotor and the second hydraulically driven rotor have opposite rotation directions, and the rotation speed of the first hydraulically driven rotor is 8-50 r / min, and the rotation speed of the second hydraulically driven rotor is 10-50 r / min; the first hydraulically driven rotor and the second hydraulically driven rotor have different rotation speeds, thereby tearing the material.

5. The process for hot sorting and upgrading of domestic waste according to claim 3 is characterized in that: The cutter heads fixed on the shafts of the two hydraulically driven rotors include: moving cutters facing each other in pairs, and stationary cutters spaced equidistantly between each group of adjacent moving cutters.

6. The process for thermal sorting and upgrading of domestic waste according to claim 3 is characterized in that: A screen is provided at the bottom of the low-speed coarse crusher, and the screen hole diameter of the screen is 100 mm.

7. The process for hot sorting and upgrading of domestic waste according to claim 1 is characterized in that: The aging temperature is 40-50° C., and the aging time is 4-9 days.

8. The process for hot sorting and upgrading of domestic waste according to claim 1, characterized in that: The thickness of the hydrogel film is 0.1-1 mm.

9. The process for hot sorting and upgrading of domestic waste according to claim 1 is characterized in that: The hydrophilic hydrogel matrix includes any one of polyvinyl alcohol, polyethylene glycol, sodium polyacrylate, sodium alginate, sodium carboxymethyl cellulose or chitosan, or a combination of at least two of them.

10. The process for hot sorting and upgrading of domestic waste according to claim 1, characterized in that: The photothermal material includes any one of graphene, carbon nanotubes, graphite powder or carbon black, or a combination of at least two of them.

11. The process for thermal sorting and upgrading of domestic waste according to claim 1 is characterized in that: The specific steps of the primary drying include: The dried material is transferred to a primary dryer for drying to obtain a first dried material; wherein the moisture content of the hydrophilic material in the first dried material is reduced to below 30%, and the moisture content of the hydrophobic material in the first dried material is reduced to below 5%; The hydrophilic material includes any one of paper products, textile products or kitchen waste or a combination of at least two of them; the hydrophobic material includes any one of plastic, foam, metal, glass, porcelain or stone or a combination of at least two of them.

12. The process for hot sorting and upgrading of domestic waste according to claim 11, characterized in that: The primary dryer is an indirect heating heat conduction dryer, including any one of a paddle dryer, a horizontal disc dryer or a steam tube rotary dryer.

13. The process for thermal sorting and upgrading of domestic waste according to claim 11, characterized in that: The parameters of the primary dryer include: the heating medium is steam at 150-200°C, and the discharge temperature of the primary dryer is 80-100°C.

14. The process for hot sorting and upgrading of domestic waste according to claim 1, characterized in that: The light material includes any one of plastic, paper products, textile products or foam products, or a combination of at least two of them; and / or, the heavy material includes any one of kitchen waste, bones, metals, glass, porcelain chips, wood or stones, or a combination of at least two of them.

15. The process for hot sorting and upgrading of domestic waste according to claim 1, characterized in that: The air separation adopts a horizontal air separator.

16. The process for thermal sorting and upgrading of domestic waste according to claim 15, characterized in that: The wind temperature of the horizontal air separator is 100-150°C.

17. The process for thermal sorting and upgrading of domestic waste according to claim 1, characterized in that: The wind direction of the air separation is 10-20°, and the wind speed of the air separation is 8-20 m / s.

18. The process for hot sorting and upgrading of domestic waste according to claim 1, characterized in that: The X-ray sorting machine used in the X-ray sorting and separation includes two strong and weak electronic X-ray sources and two independent sensors with corresponding sensitivities; The organic matter includes any one of plastic, vegetable leaves, melon peel, fruit shell, bone, paper or bamboo or wood, or a combination of at least two of them; and / or the inert matter includes any one of porcelain pieces, sand or stone, or a combination of at least two of them.

19. The process for thermal sorting and upgrading of domestic waste according to claim 1, characterized in that: The moisture content of the second dried material is 5-8%.

20. The process for hot sorting and upgrading of domestic waste according to claim 1, characterized in that: The temperature of the second drying material is 100-120°C.

21. The process for hot sorting and upgrading of domestic waste according to claim 1, characterized in that: The secondary drying adopts an airflow direct contact dryer, including any one of a multi-layer belt dryer, a rotary drum dryer or a fluidized bed dryer.

22. The process for hot sorting and upgrading of domestic waste according to claim 1, characterized in that: The heat source for the secondary drying is hot air and / or hot flue gas, and the temperature of the hot air and / or hot flue gas is 180-350°C.

23. The process for thermal sorting and upgrading of domestic waste according to claim 1, characterized in that: The baking temperature is 210-250° C., and the baking time is 20-40 min.

24. The process for hot sorting and upgrading of domestic waste according to claim 1, characterized in that: The baking is carried out using a rotary drum baking machine.

25. The process for hot sorting and upgrading of domestic waste according to claim 1, characterized in that: The heat carrier used in the baking is circulating baking gas, and the temperature of the circulating baking gas is 250-300°C.

26. The process for hot sorting and upgrading of domestic waste according to claim 1, characterized in that: The first-stage crushing adopts a hammer crusher.

27. The process for thermal sorting and upgrading of domestic waste according to claim 1, characterized in that: The particle size of the material on the sieve is greater than 5 mm, and the particle size of the material under the sieve is ≤5 mm.

28. The process for hot sorting and upgrading of domestic waste according to claim 1, characterized in that: The process method also includes the following steps: separating the metal from the screen material by eddy electric separation and magnetic separation to obtain a coked material; returning the coked material to the baking step for baking again and / or returning the coked material to the primary crushing step for crushing again.

29. The process for hot sorting and upgrading of domestic waste according to claim 1, characterized in that: The secondary crushing adopts a five-roller differential speed grinding machine.

30. The process for thermal sorting and upgrading of domestic waste according to claim 29, characterized in that: The five-roller differential grinding mill includes a differential roller group; wherein the differential roller group includes a low-speed roller, a medium-speed roller and a high-speed roller; the speed ratio of the low-speed roller, the medium-speed roller and the high-speed roller is 1:(3~5):(7~9); the speed of the low-speed roller is 15~30 rpm.

31. The process for thermal sorting and upgrading of domestic waste according to claim 30, characterized in that: The differential grinder includes a cooling forming roller group; wherein the cooling forming roller group includes a low-speed cooling roller and a high-speed cooling roller; the speed ratio of the low-speed cooling roller and the high-speed cooling roller is 1:(1.14~1.19); the speed of the low-speed cooling roller is 20~30 rpm; the temperature of the low-speed cooling roller and the high-speed cooling roller is independently 10~20°C.

32. An improved biomass powder, characterized in that: The upgraded biomass powder is prepared by the process for thermal sorting and upgrading of domestic waste as described in any one of claims 1 to 31.

33. The upgraded biomass powder according to claim 32, characterized in that: The particle size of the upgraded biomass powder is 500-899 μm.

34. The upgraded biomass powder according to claim 32, characterized in that: The specific surface area of ​​the upgraded biomass powder is 158-242 m 2 / g.

35. The upgraded biomass powder according to claim 32, characterized in that: The total moisture content of the upgraded biomass powder is ≤3%.

36. The upgraded biomass powder according to claim 32, characterized in that: The ash value of the upgraded biomass powder is less than 15%.

37. The upgraded biomass powder according to claim 32, characterized in that: The energy density of the upgraded biomass powder is 12.5-30 MJ / kg.

38. The upgraded biomass powder according to claim 32, characterized in that: The gasification time for the upgraded biomass powder to be completely gasified at a temperature of 1300° C. is less than 7 s.

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