Process method for improving quality of household garbage by hot sorting and quality-improved biomass powder obtained by process method

Abstract

The invention provides a process method for improving quality of household garbage through thermal sorting and quality-improved biomass powder obtained through the process method, and relates to the technical field of solid waste treatment. The technological method comprises the following steps that the household garbage is subjected to coarse crushing, and a crushed material with the particle size smaller than or equal to 100 mm is obtained; curing and dehydrating the crushed material, and drying after percolate flows out to obtain a dried material; performing primary drying on the dried material to obtain a first dried material; carrying out hot air separation on the first dry material to respectively obtain a heavy substance and a light substance; carrying out X-ray separation on the heavy substance to respectively obtain an organic matter and an inert matter; carrying out secondary drying on the light substance and the organic matter to obtain a second dried material; the second dry material is sequentially subjected to baking, cooling, primary crushing and primary screening, and oversize products and undersize products are obtained respectively; and carrying out second-stage crushing and second-stage screening on the screen underflow to obtain the 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] With the acceleration of global urbanization, the amount of domestic waste is showing a sharp growth trend. According to data from the United Nations Environment Program, the amount of urban domestic waste generated worldwide exceeds 2 billion tons per year, and this figure is still growing at a rate of about 3% per year. It not only occupies a large amount of land resources, but also causes serious environmental pollution problems such as groundwater pollution, soil pollution and air pollution if not handled properly. Therefore, how to deal with domestic waste efficiently and environmentally friendly has become one of the major challenges of global environmental governance.

[0003] 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.

[0004] 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.

[0005] At present, there are some technical solutions for hot 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 part of the recyclables in the garbage, but have poor removal effects on organic matter and other impurities (such as an automatic sorting device for recyclable domestic waste disclosed in CN202410204718.6, an automatic sorting system for domestic waste 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 a high sorting effect, they are difficult to promote and use due to high equipment investment costs and high operating energy consumption (such as the domestic waste pretreatment system based on high-pressure extrusion disclosed in CN201710043977.5, the system and method for treating domestic waste disclosed in CN201710154378.0, the system and method for treating domestic waste disclosed in CN201611192907.8, and a method for treating fly ash from incineration of domestic waste disclosed in CN201610472920.2). Finally, there are some methods that directly apply heat treatment technology to mixed domestic waste without pretreatment, which has problems such as high energy consumption, unstable treatment effect, and difficult to control product quality (such as the low-energy domestic waste high-pressure extrusion dry-wet separation equipment and method disclosed in CN201710044253.2).

[0006] Therefore, the current garbage disposal methods often have several problems: 1. It is difficult to fully crush the garbage, and due to the high water content of the garbage, it is easy to stick to the inner wall of the crusher, making it difficult for some garbage to be crushed again; 2. The composition of domestic garbage is complex, with a large amount of plastic and organic matter. The existing sorting method is difficult to fully separate the different substances, which can easily lead to the re-discharge of plastic and organic matter into the environment to cause pollution; 3. The amount of garbage leachate generated is large, the COD and BOD content in the leachate is high, and the cycle of removing moisture is long and the efficiency is low; 4. After the garbage is dehydrated, it is generally dried by hot air, and the obtained material is then baked or pyrolyzed for resource utilization, but the hot air drying method is not sufficient, so that the material entering the baking device or pyrolysis device still has a certain amount of moisture, resulting in insufficient baking and serious internal garbage adhesion; 5. The product yield obtained by the existing garbage baking or pyrolysis technology is low, the energy loss is large, the energy consumption is high, and the problem of dioxins cannot be completely solved.

[0007] In view of this, the present invention is proposed. Summary of the invention

[0008] In view of the deficiencies in 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 thereby. The process method is a process method for thermal sorting and upgrading of domestic waste that integrates pretreatment, efficient separation and deep upgrading. The domestic waste is subjected to multiple processes such as coarse crushing, aging and dehydration, drying, primary drying, hot air separation, X-ray separation, secondary drying, baking, cooling, crushing and screening, and finally high value-added upgraded biomass powder is obtained. The present invention aims to achieve effective separation and upgrading of various components in domestic waste through a series of scientific and reasonable process steps, especially for organic components, to improve their utilization value as fuel or raw materials through deep processing, while reducing the negative impact of inert substances on subsequent processing processes, which not only improves the sorting efficiency, but also effectively solves the problems existing in traditional treatment methods. It has the characteristics of simple operation and low energy consumption, and has good economy and environmental protection in practical applications. The process method of the present invention prepares upgraded biomass powder by baking domestic waste, improves fuel properties, obtains upgraded biomass powder with high calorific value, has more concentrated energy, and has a high energy yield, thereby achieving full resource utilization of domestic waste and being environmentally friendly without dioxin emissions.

[0009] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0010] In a first aspect, the present invention provides a process for hot sorting and upgrading of domestic waste, the process comprising the following steps:

[0011] The crushed material is matured and dehydrated, and dried after the leachate flows out to obtain a dried material;

[0012] The dried material is subjected to primary drying to obtain a first dried material;

[0013] The first dried material is subjected to hot air separation to obtain heavy matter and light matter respectively;

[0014] The heavy substances are subjected to magnetic separation, vortex separation, color separation and X-ray separation to obtain magnetic metals (iron), non-magnetic metals (copper, aluminum, etc.), glass, organic matter and inert matter respectively;

[0015] The light matter and the organic matter are subjected to secondary drying together to obtain a second dried material;

[0016] 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;

[0017] The screened material is subjected to secondary crushing and secondary screening to obtain improved biomass powder;

[0018] The inert residue obtained by the X-ray separation is processed into sand and gravel by a sand making machine.

[0019] In the present invention, through the above-mentioned process steps of hot sorting and upgrading of domestic waste, domestic waste is recycled and converted into high calorific value, high-quality upgraded biomass powder, which is convenient for storage and transportation, enriches the back-end processing process route, and realizes the reduction, harmlessness and resource treatment of domestic waste. And the method can be prepared at low cost and on a large scale to upgrade the quality and efficiency of domestic waste and convert it into upgraded biomass powder with uniform component materials, high purity and high energy density. No dioxins are generated during the conversion process, which solves the problem of dioxin treatment in traditional domestic waste incineration treatment methods. At the same time, the amount of flue gas generated in the method is small, the amount of dust carried by the flue gas is low, and the pollution to the environment is small.

[0020] Preferably, the specific steps of the coarse crushing include:

[0021] 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 ≤100mm and crushed materials with a particle size >100mm. The crushed materials with a particle size >100mm are returned to the coarse crusher for coarse crushing and screening again until the particle size of the obtained materials is ≤100mm.

[0022] Preferably, the coarse crusher is a low-speed coarse crusher, and two hydraulically or motor-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 or motor-driven rotors; the fixed ends of the two hydraulically driven rotors are equipped with double-row spherical roller bearings, and the following ends of the two hydraulically driven rotors are equipped with two thrust spherical roller bearings.

[0023] In the present invention, the configuration of the above-mentioned low-speed coarse crusher not only enables the rotor to withstand tangential and radial stresses, but also eliminates axial stress when the rotor encounters flexible, high-hardness materials that are difficult to crush or cannot be crushed, and protects the blade / knife shaft and support / transmission bearings from damage. The crushing of domestic garbage is achieved through the combined effects of tearing, shearing and squeezing, thereby significantly improving the crushing efficiency, thereby improving the crushing effect and reducing the number of repeated cycles of coarse crushing.

[0024] Preferably, 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 directions of rotation, and the rotation speed of the first hydraulically driven rotor is 8 to 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 rotation speed of the second hydraulically driven rotor is 10 to 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 first hydraulically driven rotor and the second hydraulically driven rotor have different rotation speeds, thereby tearing the material.

[0025] Preferably, 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.

[0026] Preferably, a screen is provided at the bottom of the coarse crusher, and the screen has a mesh size of 100 mm.

[0027] Preferably, the aging temperature is 40-50°C, for example, 40°C, 42°C, 44°C, 46°C, 48°C, 50°C, etc., and the aging time is 4-9 days, for example, 4 days, 5 days, 6 days, 7 days, 8 days, 9 days, etc.

[0028] Preferably, the specific steps of ripening include:

[0029] The crushed materials are transferred to the garbage storage tank, and the first ventilation is carried out on the 1st to 3rd day, and the oxygen content in the wind flow is ensured to be 15-18%, and the ventilation rate is 0.2-0.3 L·kg -1 DM·min -1 , the air flow 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 0.3-0.4L·kg -1 DM·min -1 , the wind flow temperature is 22 ~ 25 ℃.

[0030] In the present invention, by carrying out maturation and dehydration under the above-mentioned specific conditions of oxygen content and ventilation rate, it is ensured that at a lower maturation temperature, the outflow of leachate from the crushed garbage material is accelerated, and it is also ensured that the leachate flows out more fully, thereby significantly improving the maturation efficiency and reducing the difficulty of subsequent drying.

[0031] Preferably, the drying includes heating drying and / or light drying.

[0032] Preferably, the heating and drying is carried out through a heating pipe arranged at the bottom of the garbage storage tank, and the heating pipe is filled with water vapor and / or hot water.

[0033] Preferably, the flow rate of water vapor and / or hot water in the heating pipe maintains the temperature in the storage tank at 40-80°C, for example, it can be 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, etc.

[0034] In the present invention, when the temperature is controlled by utilizing the water vapor or hot water pipeline for heat exchange of the rear end waste heat, the flow rate of the water vapor or hot water can be adjusted to control the temperature.

[0035] Preferably, 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 material under sunlight to evaporate the solution in the garbage leachate, and completing the drying of the garbage.

[0036] In the present invention, when light drying is adopted, a hydrogel film is formed on the surface of the crushed material, and the hydrogel film can absorb and retain moisture between the garbage. Driven by light, a hydrogel-steam interface can be quickly formed, and light evaporation can be performed to significantly improve the evaporation efficiency, while achieving the purpose of low-energy consumption and high-speed drying of garbage leachate.

[0037] Preferably, the thickness of the hydrogel film is 0.1-1 mm, for example, 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.

[0038] Preferably, 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, for example, it can be 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, etc.

[0039] In the present invention, the hydrogel membrane is based on a hydrophilic hydrogel, into which a certain amount of photothermal material is doped. The hydrophilicity of the hydrophilic hydrogel is used to improve the adsorption of water, and the load of the photothermal material is used to provide energy for converting liquid water into gaseous water molecules, so as to further increase the evaporation rate of water, thereby making the drying of the garbage controllable and sufficient.

[0040] Preferably, the hydrophilic hydrogel matrix comprises any one of polyvinyl alcohol, polyethylene glycol, sodium polyacrylate, sodium alginate, sodium carboxymethyl cellulose or chitosan, or a combination of at least two thereof.

[0041] Preferably, the photothermal material includes any one of graphene, carbon nanotubes, graphite powder or carbon black, or a combination of at least two of them.

[0042] Preferably, the specific steps of the primary drying include:

[0043] 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%, 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 below 5%, for example, it can be 5%, 4%, 3%, 2%, 1%, etc.

[0044] The hydrophilic material includes any one of paper products, textile products or kitchen waste (such as melon peels, fruit shells, leftovers, leftovers, etc.) 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.

[0045] In the present invention, the primary dryer is an indirect heating heat conduction dryer, including a paddle dryer, a horizontal disc dryer, a steam tube rotary dryer, etc.; the parameters of the primary dryer include: the heating medium is steam at 150 to 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 to 100°C, for example, it can be 80°C, 85°C, 90°C, 95°C, 100°C, etc.

[0046] Preferably, the light materials include any one of plastics, paper products, textile products or foam products, or a combination of at least two of them; and / or, the heavy materials include any one of kitchen waste such as melon peels, fruit shells, leftovers, etc. (e.g. melon peels, fruit shells, leftovers, etc.), bones, metals, glass, porcelain pieces, wood or stones, or a combination of at least two of them.

[0047] In the present invention, since there is a certain density difference between light materials and heavy materials, light materials and heavy materials can be separated by adjusting the wind speed, and the entire air separation process is completed in a moving airflow field; loose materials are separated by volume and mass under the combined action of their own gravity, inertia and airflow drag; materials with different densities are separated under the action of airflow to obtain different types of final products.

[0048] Preferably, the air separation adopts a horizontal air separator.

[0049] Preferably, the wind temperature of the horizontal air separator is 100-150°C, for example, it can be 100°C, 110°C, 120°C, 130°C, 140°C, or 150°C.

[0050] Preferably, the wind 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 wind speed of the air separation is 8-20m / s, for example, it can be 8m / s, 10m / s, 12m / s, 14m / s, 16m / s, 18m / s, 20m / s, etc.

[0051] Preferably, the X-ray sorting machine includes two electron X-ray sources, strong and weak, and two independent sensors with corresponding sensitivities; the organic matter includes any one of plastic, vegetable leaves, melon rinds, fruit shells, bones, 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 stones, or a combination of at least two of them.

[0052] In the present invention, heavy materials are selected by X-rays, and separated according to the different density images of the materials, to obtain organic matter and inert matter respectively; in addition, light materials and the organic matter selected by X-rays are simultaneously subjected to secondary drying, because after the primary drying, the materials still contain a small amount of moisture, and the moisture in the materials is further reduced by secondary drying, which facilitates the baking of the materials.

[0053] Preferably, the moisture content of the second dried material is 5-8%, for example, 5%, 6%, 7%, 8%, etc.

[0054] Preferably, the temperature of the second drying material is 100-120°C, for example, 100°C, 105°C, 110°C, 115°C, 120°C, etc.

[0055] Preferably, 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.

[0056] 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.

[0057] Preferably, the baking temperature is 210-250°C, for example, 210°C, 220°C, 230°C, 240°C, 250°C, etc., and the baking time is 20-40min, for example, 20min, 25min, 30min, 35min, 40min, etc.

[0058] Preferably, the baking is carried out using a rotary baking machine.

[0059] Preferably, the baking heat carrier is circulating baking gas, and the temperature of the circulating baking gas is 250-300°C, for example, 250°C, 260°C, 270°C, 280°C, 290°C, 300°C, etc.

[0060] Preferably, the primary crushing adopts a hammer crusher.

[0061] In the present invention, a hammer crusher is used for primary crushing. The hammer crusher applies impact force to the material when the rotating hammer moves at high speed to crush it. It is mainly composed of a casing, a rotor, a hammer head, a screen plate, etc. This crusher has a simple structure, is easy to operate, and can efficiently complete the crushing process.

[0062] Preferably, the particle size of the above-sieve material is greater than 5 mm, for example, it may be 5.1 mm, 5.5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, etc., and the particle size of the below-sieve material is ≤5 mm, for example, it may be 5 mm, 4 mm, 3 mm, 2 mm, 1 mm, 0.5 mm, etc.

[0063] Preferably, the main process of the primary crushing and primary screening includes:

[0064] (a) Feeding: The material enters the crusher through the feed port. The size of the feed port should be adapted to the specifications and output of the crusher.

[0065] (b) High-speed rotation: The rotor inside the crusher rotates at high speed. There are multiple hammers on the rotor. These hammers have a large linear speed due to the high-speed rotation;

[0066] (c) Impact crushing: After the material enters the crusher, it is impacted by the high-speed rotating hammer and thus crushed. The impact force is the main force of crushing and can effectively crush the material;

[0067] (d) Grinding effect: In addition to impact crushing, the material will also be subjected to grinding effect inside the crusher. This is because the material will rub and collide with the inner wall of the casing, the screen plate and the hammer head on the rotor during the crushing process;

[0068] (e) Particle size screening: The crushed material passes through a sieve plate with sieve holes of a certain size. The material larger than the sieve holes will be retained on the sieve plate for further crushing, while the material smaller than the sieve holes will be discharged through the sieve plate and become the finished product;

[0069] (f) Discharge: Finished materials are discharged from the discharge port, the size of which can be adjusted to control the size of the finished materials. Unqualified large particles may re-enter the crusher for re-crushing.

[0070] Preferably, in step (b), the rotation speed of the rotor inside the crusher is 750-1500rpm, for example, it can be 750rpm, 800rpm, 850rpm, 900rpm, 1000rpm, 1100rpm, 1200rpm, 1300rpm, 1400rpm, 1500rpm, etc., and the linear speed of the hammer head is 25-70m / s, for example, it can be 25m / s, 30m / s, 35m / s, 40m / s, 45m / s, 50m / s, 55m / s, 60m / s, 65m / s, 70m / s, etc.

[0071] Preferably, in step (c), the impact force of the hammer head is 300-500N, for example, it can be 300N, 350N, 400N, 450N, 500N, etc.

[0072] Preferably, in step (e), the particle size of the oversize material remaining on the sieve plate is greater than 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 is ≤5 mm, for example, it can be 5 mm, 4 mm, 3 mm, 2 mm, 1 mm, 0.5 mm, etc.

[0073] Preferably, the process method further 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.

[0074] Among them, during eddy current sorting, the materials are sorted and classified by an eddy current separator. When the eddy current separator is working, a high-frequency alternating strong magnetic field will be generated on the surface of the sorting roller. When the metal enters the strong magnetic field sorting area, an eddy current will be induced inside the metal block. The magnetic field generated by this eddy current is opposite to the original magnetic field, and there is a mutual repulsion effect. The effect of this repulsion force can throw the metal block forward to achieve separation. Among them, magnetic separation uses the magnetic or non-magnetic characteristics of different materials. The magnetic separator can be used to extract the useful magnetic materials from the non-magnetic materials to achieve the purpose of separating the two.

[0075] Preferably, the secondary crushing adopts a five-roller differential speed grinding mill.

[0076] In the present invention, the secondary crushing adopts a five-roller differential grinder, which can further grind the material to obtain powder that meets the required particle size. The differential grinder includes a frame, a differential roller group, a cooling and forming roller group, and a temperature control component. The differential roller group includes: a low-speed roller, a medium-speed roller and a high-speed roller, and a gear group that drives the differential roller to rotate. The cooling and forming roller group includes a low-speed cooling roller, a high-speed cooling roller and a gear that drives them to rotate. The temperature control component is a high-pressure and high-temperature water temperature machine, a heating pipeline, a refrigerator and a cooling pipeline, and then the temperature control component can control the surface temperature of the cooling roller and the differential roller. The use of this five-roller machine can not only fully grind the material, but also reduce the influence of temperature on the grinding effect in conjunction with the temperature control component.

[0077] Preferably, the differential grinder comprises a differential roller group; wherein the differential roller group comprises 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 15-30rpm.

[0078] Preferably, 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 20~30rpm; the temperature of the low-speed cooling roller and the high-speed cooling roller is independently 10~20℃.

[0079] In a second aspect, the present invention provides an upgraded biomass powder, which is prepared by the process for thermal sorting and upgrading of domestic waste as described in the first aspect.

[0080] Preferably, the particle size of the upgraded biomass powder is 500 to 899 μm.

[0081] Preferably, the specific surface area of ​​the upgraded biomass powder is 158 to 242 m 2 / g.

[0082] Preferably, the total moisture content of the upgraded biomass powder is ≤3%.

[0083] Preferably, the ash value of the upgraded biomass powder is less than 15%.

[0084] Preferably, the energy density of the upgraded biomass powder is 12.5 to 30 MJ / kg.

[0085] Preferably, the gasification time for the upgraded biomass powder to be completely gasified at a temperature of 1300° C. is less than 7 seconds.

[0086] Compared with the prior art, the present invention has the following beneficial effects:

[0087] (1) The process method described in the present invention is a process method for thermal sorting and upgrading of domestic waste that integrates pretreatment, efficient separation and deep upgrading. The process involves performing coarse crushing, maturation and dehydration, drying, primary drying, hot air separation, X-ray separation, secondary drying, baking, cooling, crushing and screening on the domestic waste to finally obtain high value-added upgraded biomass powder.

[0088] (2) The process method of the present invention can effectively separate and improve the components of domestic waste, especially the organic components, by deep processing to improve their utilization value as fuel or raw materials, while reducing the negative impact of inert matter on subsequent treatment processes. 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.

[0089] (3) The present invention converts domestic waste into high-calorific value, high-quality upgraded biomass powder by low-temperature baking, which is convenient for storage and transportation, enriches the back-end processing process route, and achieves 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 dioxins are generated during the conversion process, thus solving the problem of dioxin treatment in traditional domestic waste incineration treatment methods. In addition, the process method of the present invention generates a small amount of flue gas, a low amount of dust carried by the flue gas, and little pollution to the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0090] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0091] Figure 1 This is a flow chart of the process method for thermal sorting and quality improvement of domestic waste according to the present invention. DETAILED DESCRIPTION

[0092] 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 meaning and scope of the terms should be clear, however, in the case of any potential ambiguity, the definitions provided herein take precedence over any dictionary or external definitions. In this application, unless otherwise stated, the use of "or" means "and / or". In addition, the use of the term "including" and other forms is non-limiting.

[0093] It should be noted that specific details are described in the following description to facilitate a full understanding of the present invention. However, the present invention can be implemented in a variety of other ways different from those described herein, and those skilled in the art can make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0094] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0095] The present invention is further described below by way of examples. Unless otherwise specified, the materials in the examples are prepared according to existing methods or directly purchased from the market.

[0096] Example 1

[0097] This embodiment provides a process for hot sorting and quality improvement of domestic waste, such as Figure 1 As shown, the process comprises the following steps:

[0098] S1. Coarse crushing:

[0099] The domestic garbage is fed into the coarse crusher through a grab bucket for coarse crushing and screening to obtain crushed materials with a particle size of ≤100mm and crushed materials with a particle size of >100mm. The crushed materials with a particle size of >100mm are returned to the coarse crusher for coarse crushing and screening again. The crushing needs to be repeated 3 times, and the particle size of the materials obtained by coarse crushing is ≤100mm.

[0100] 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; the fixed ends of the two hydraulically driven rotors are equipped with double-row self-aligning roller bearings, and the following ends of the two hydraulically driven rotors are equipped with two thrust self-aligning roller bearings;

[0101] 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 have opposite directions of rotation, and the rotation speed of the first hydraulically driven rotor is 50r / min, and the rotation speed of the second hydraulically driven rotor is 10r / min; the rotation speeds of the first hydraulically driven rotor and the second hydraulically driven rotor are different, thereby tearing the materials; the cutter heads fixed on the axes of the two hydraulically driven rotors include: 5 groups of moving cutters facing each other, and a static cutter in the middle of each group of adjacent moving cutters spaced equidistantly, and a screen is provided at the bottom of the coarse crusher, and the screen hole diameter of the screen is 100mm.

[0102] S2, Ripening, Dehydration and Drying:

[0103] (a) The crushed material is transferred to a garbage storage tank and aged for 6 days at 45°C to dehydrate the material, so that leachate flows out of the garbage material; wherein, the first ventilation is performed on the first to second day, and the oxygen content in the wind flow is ensured to be 16%, and the ventilation rate is 0.25 L·kg -1 DM·min -1 , the air flow temperature is 26℃; after the first ventilation, turn the material, and conduct the second ventilation on the 3rd to 6th day, and ensure that the oxygen content in the air flow is 19%, and the ventilation rate is 0.35L·kg -1 DM·min -1 , the temperature of the wind flow is 23°C;

[0104] (b) spraying the hydrogel solution into a 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; wherein the doping amount of the graphene is 2%), and irradiating the crushed material under sunlight at 25° C. for 60 min to evaporate the solution in the garbage leachate, thereby completing the drying of the garbage and obtaining a dried material with a water content of 38%.

[0105] S3, primary drying:

[0106] The dried material is transferred to a primary 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 2%; the hydrophilic material includes paper products, textile products, melon peels, fruit shells, leftovers and other kitchen waste; the hydrophobic material includes plastics, foams, metals, glass, porcelain chips, stones, etc.;

[0107] The parameters of the primary drying include: using a paddle dryer, the heating medium is 200°C steam, the discharge temperature of the primary dryer is 100°C, and the heat transfer area of ​​the paddle dryer is 280m 2 The power of the paddle dryer is 45kW, the speed of the paddle is 12r / min, and the effective volume of the paddle dryer is 12.8m 3 .

[0108] S4, hot air separation:

[0109] The first dried material is subjected to hot air separation by a horizontal air separator to obtain heavy matter and light matter respectively; the light matter comprises any one of plastic, paper products, textile products or foam products or a combination of at least two thereof; and / or the heavy matter comprises any one of kitchen waste such as melon peels, fruit shells, leftovers, bones, metals, glass, porcelain pieces, wood or stones or a combination of at least two thereof;

[0110] Among them, the air inlet of the horizontal air separator is rectangular in shape, the height of the air inlet is 500mm, the height of the center of the air inlet is 1550mm, and the wind temperature is 150°C; the wind direction of the air separation is 15°, and the wind speed is 10m / s.

[0111] S5, X-ray separation:

[0112] The heavy matter is subjected to X-ray separation to obtain organic matter and inert matter respectively, the X-ray separator comprises two electron X-ray sources, strong and weak, and two independent sensors with corresponding sensitivities; the organic matter comprises 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; the inert matter comprises any one of porcelain pieces, sand or stone, or a combination of at least two of them.

[0113] S6, Secondary Drying:

[0114] The light material obtained in S4 and the organic matter obtained in S5 are mixed and subjected to secondary drying in a multi-layer belt dryer to obtain a second dried material having a moisture content of 5% and a temperature of the second dried material of 120° C.;

[0115] The heat source of the secondary drying is hot air, the temperature of the hot air is 350°C, and the intensity of the secondary drying is 10kg water / m 2 h; the secondary drying conveyor belt is a plate conveyor belt; wherein the plate conveyor belt is made of a stainless steel sheet with a thickness of 1 mm, and is provided with 1.5 mm × 6 mm long strip punching holes, with an opening rate of 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 matter and organic matter is 50 mm, and the load of the material layer is 500 kg / m 2 ; The total resistance through the conveyor belt and the material layer is 350Pa; the flow velocity of the drying medium in the multi-layer belt dryer is 1.0m / s.

[0116] S7. Baking:

[0117] The second dried material is transferred to a baking device and baked at 230° C. for 40 minutes to obtain a baked material; wherein the baking is carried out using a rotary drum baking machine; the baking heat carrier is circulating baking gas, and the temperature of the circulating baking gas is 300° C.

[0118] S8, Cooling

[0119] The roasted material was cooled to 25° C. at a cooling rate of 5° C. / min, and cooled at this temperature for 40 minutes to catalyze the material, thereby obtaining a cooled roasted material.

[0120] S9, primary crushing and primary screening:

[0121] The cooled roasted material is subjected to primary crushing and primary screening in sequence, ensuring that the average processing rate of this process is 80 t / h; wherein the primary crushing and primary screening process includes:

[0122] (a) Feeding: The material enters the crusher through the feed port. The size of the feed port should be adapted to the specifications and output of the crusher.

[0123] (b) High-speed rotation: The rotor inside the crusher rotates at a high speed, and there are multiple hammers on the rotor. These hammers have a large linear velocity due to the high-speed rotation; wherein the rotation speed of the rotor inside the crusher is 1000 rpm, and the linear velocity of the hammers is 70 m / s;

[0124] (c) Impact crushing: After the material enters the crusher, it is impacted by the high-speed rotating hammer and thus crushed. The impact force is the main force of crushing and can effectively crush the material. The impact force of the hammer is 450N;

[0125] (d) Grinding effect: In addition to impact crushing, the material will also be subjected to grinding effect inside the crusher. This is because the material will rub and collide with the inner wall of the casing, the screen plate and the hammer head on the rotor during the crushing process;

[0126] (e) Particle size screening: The crushed material passes through a sieve plate with sieve holes of a certain size. The material larger than the sieve holes will be retained on the sieve plate for further crushing, while the material smaller than the sieve holes will be discharged through the sieve plate to become the finished product. Among them, the particle size of the sieve-surface material retained on the sieve plate is greater than 5mm (accounting for 25%); the particle size of the sieve-surface material discharged through the sieve plate is ≤5mm (accounting for 75%).

[0127] (f) Discharge: Finished materials are discharged from the discharge port, the size of which can be adjusted to control the size of the finished materials. Unqualified large particles may re-enter the crusher for re-crushing.

[0128] S10, secondary crushing and secondary screening:

[0129] The screened material is subjected to secondary crushing by a five-roll differential speed grinder, and then subjected to secondary screening to obtain improved biomass powder;

[0130] Wherein, the differential grinder 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 1:3:9; the speed of the low-speed roller is 30rpm; the differential grinder includes a cooling and forming roller group; the cooling and 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 1:1.19; the speed of the low-speed cooling roller is 30rpm; the temperature of the low-speed cooling roller is 12°C, and the temperature of the high-speed cooling roller is 18°C.

[0131] Example 2

[0132] This embodiment provides a process for hot sorting and quality improvement of domestic waste, such as Figure 1 As shown, the process comprises the following steps:

[0133] S1. Coarse crushing:

[0134] The domestic garbage is conveyed into the coarse crusher through a conveyor for coarse crushing and screening to obtain crushed materials with a particle size of ≤100mm and crushed materials with a particle size of >100mm. The crushed materials with a particle size of >100mm are returned to the coarse crusher for coarse crushing and screening again. The crushing needs to be repeated 5 times until the particle size of the coarse crushed materials is ≤100mm.

[0135] The coarse crusher is a low-speed coarse crusher, and two motor-driven rotors are arranged in the crushing chamber of the low-speed coarse crusher; cutter heads are fixed on the shafts of the two motor-driven rotors; the fixed ends of the two motor-driven rotors are equipped with double-row self-aligning roller bearings, and the following ends of the two motor-driven rotors are equipped with two thrust self-aligning roller bearings;

[0136] Among them, the two motor-driven rotors include a first motor-driven rotor and a second motor-driven rotor; the first motor-driven rotor and the second motor-driven rotor have opposite directions of rotation, and the rotation speed of the first motor-driven rotor is 8r / min, and the rotation speed of the second motor-driven rotor is 50r / min; the first motor-driven rotor and the second motor-driven rotor have different rotation speeds, thereby tearing the materials, and the cutter heads fixed on the axes of the two motor-driven rotors include: 5 groups of moving cutters facing each other, and a static cutter in the middle of each group of adjacent moving cutters with equal distances between them, and a screen is provided at the bottom of the coarse crusher, and the screen hole diameter of the screen is 100mm.

[0137] S2, Ripening, Dehydration and Drying:

[0138] (a) The crushed material is transferred to a garbage storage tank and aged for 9 days at 40°C to dehydrate the material, so that leachate flows out of the garbage material; wherein, the first ventilation is performed on the 1st to 3rd day, and the oxygen content in the wind flow is ensured to be 15%, and the ventilation rate is 0.3L·kg -1 DM·min -1 , the air flow temperature is 28℃; after the first ventilation, turn the material, and conduct the second ventilation on the 4th to 9th day, and ensure that the oxygen content in the air flow is 18%, and the ventilation rate is 0.4L·kg -1 DM·min -1 , the temperature of the wind flow is 25℃;

[0139] (b) spraying 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 chitosan matrix and carbon nanotubes doped in the chitosan matrix; wherein the doping amount of the carbon nanotubes is 2%), and irradiating the crushed material under sunlight at 25° C. for 50 min to evaporate the solution in the garbage leachate, thereby completing the drying of the garbage and obtaining a dried material with a water content of 39%.

[0140] S3, primary drying:

[0141] The dried material is transferred to a primary 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 25%, and the moisture content of the hydrophobic material is reduced to 3%; the hydrophilic material includes paper products, textile products, melon peels, fruit shells, leftovers and other kitchen waste; the hydrophobic material includes plastics, foams, metals, glass, porcelain chips, stones, etc.;

[0142] The primary dryer is an indirect heating heat conduction dryer, and a horizontal disc dryer is used here; the parameters of the primary dryer include: the heating medium is 150°C steam, and the discharge temperature of the primary dryer is 80°C.

[0143] S4, hot air separation:

[0144] The first dried material is subjected to hot air separation by a horizontal air separator to obtain heavy matter and light matter respectively; the light matter comprises any one of plastic, paper products, textile products or foam products or a combination of at least two thereof; and / or the heavy matter comprises any one of kitchen waste such as melon peels, fruit shells, leftovers, bones, metals, glass, porcelain pieces, wood or stones or a combination of at least two thereof;

[0145] Among them, the air inlet of the horizontal air separator is rectangular in shape, the height of the air inlet is 500mm, and the height of the center of the air inlet is 1550mm; the wind temperature is 100°C; the wind direction of the air separation is 15°, and the wind speed is 15m / s.

[0146] S5, X-ray separation:

[0147] The heavy matter is subjected to X-ray separation to obtain organic matter and inert matter respectively, the X-ray separator comprises two electron X-ray sources, strong and weak, and two independent sensors with corresponding sensitivities; the organic matter comprises 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; the inert matter comprises any one of porcelain pieces, sand or stone, or a combination of at least two of them.

[0148] S6, Secondary Drying:

[0149] The light material obtained in S4 and the organic matter obtained in S5 are mixed and subjected to secondary drying in a rotary drum dryer to obtain a second dried material;

[0150] Wherein, the temperature of the secondary drying material is 100°C; the drying medium is hot flue gas, and the temperature of the hot flue gas is 180°C.

[0151] S7. Baking:

[0152] The second dried material is transferred to a baking device and baked at 210°C for 20 minutes to obtain a baked material. The baking heat carrier is a circulating baking gas, and the temperature of the circulating baking gas is 250°C.

[0153] S8, Cooling

[0154] The baked material was cooled to 25° C. at a cooling rate of 5° C. / min, and cooled at this temperature for 60 min to embrittle the material, thereby obtaining a cooled baked material.

[0155] S9, primary crushing and primary screening:

[0156] The cooled roasted material is subjected to primary crushing and primary screening in sequence, ensuring that the average processing rate of this process is 50 t / h; wherein the primary crushing and primary screening process includes:

[0157] (a) Feeding: The material enters the crusher through the feed port. The size of the feed port should be adapted to the specifications and output of the crusher.

[0158] (b) High-speed rotation: The rotor inside the crusher rotates at a high speed, and there are multiple hammers on the rotor. These hammers have a large linear velocity due to the high-speed rotation; wherein the rotation speed of the rotor inside the crusher is 1000 rpm, and the linear velocity of the hammers is 50 m / s;

[0159] (c) Impact crushing: After the material enters the crusher, it is impacted by the high-speed rotating hammer and thus crushed. The impact force is the main force of crushing and can effectively crush the material. The impact force of the hammer is 400N;

[0160] (d) Grinding effect: In addition to impact crushing, the material will also be subjected to grinding effect inside the crusher. This is because the material will rub and collide with the inner wall of the casing, the screen plate and the hammer head on the rotor during the crushing process;

[0161] (e) Particle size screening: The crushed material passes through a sieve plate with sieve holes of a certain size. The material larger than the sieve holes will be retained on the sieve plate for further crushing, while the material smaller than the sieve holes will be discharged through the sieve plate to become the finished product. Among them, the particle size of the sieve-surface material retained on the sieve plate is greater than 5mm (accounting for 27%); the particle size of the sieve-surface material discharged through the sieve plate is ≤5mm (accounting for 73%).

[0162] (f) Discharge: Finished materials are discharged from the discharge port, the size of which can be adjusted to control the size of the finished materials. Unqualified large particles may re-enter the crusher for re-crushing.

[0163] S10, secondary crushing and secondary screening:

[0164] The screened material is subjected to secondary crushing by a five-roll differential speed grinder, and then subjected to secondary screening to obtain improved biomass powder;

[0165] Wherein, the differential grinder 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 1:5:8; the speed of the low-speed roller is 25rpm; the differential grinder includes a cooling and forming roller group; the cooling and 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 1:1.15; the speed of the low-speed cooling roller is 30rpm; the temperature of the low-speed cooling roller is 15°C, and the temperature of the high-speed cooling roller is 19°C.

[0166] Example 3

[0167] This embodiment provides a process for hot sorting and quality improvement of domestic waste, such as Figure 1 As shown, the process comprises the following steps:

[0168] S1. Coarse crushing:

[0169] The domestic garbage is fed into the coarse crusher through a grab bucket for coarse crushing and screening to obtain crushed materials with a particle size of ≤100mm and crushed materials with a particle size of >100mm. The crushed materials with a particle size of >100mm are returned to the coarse crusher for coarse crushing and screening again. The crushing needs to be repeated 3 times until the particle size of the coarse crushed materials is ≤100mm.

[0170] 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; the fixed ends of the two hydraulically driven rotors are equipped with double-row self-aligning roller bearings, and the following ends of the two hydraulically driven rotors are equipped with two thrust self-aligning roller bearings;

[0171] 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 have opposite directions of rotation, and the rotation speed of the first hydraulically driven rotor is 15r / min, and the rotation speed of the second hydraulically driven rotor is 30r / min; the cutter heads fixed on the axes of the two hydraulically driven rotors include: 5 groups of moving cutters facing each other, and static cutters in the middle of each group of adjacent moving cutters spaced equidistantly, and a screen is provided at the bottom of the coarse crusher, and the screen hole diameter of the screen is 100mm.

[0172] S2, Ripening, Dehydration and Drying:

[0173] (a) The crushed material is transferred to a garbage storage tank and aged for 9 days at 40°C to dehydrate the material, so that leachate flows out of the garbage material; wherein, the first ventilation is performed on the 1st to 3rd day, and the oxygen content in the wind flow is ensured to be 18%, and the ventilation rate is 0.2L·kg -1 DM·min -1 , the air temperature is 25℃; after the first ventilation, turn the material, and conduct the second ventilation on the 4th to 9th day, and ensure that the oxygen content in the air is 20%, and the ventilation rate is 0.3L·kg -1 DM·min -1 , the temperature of the wind flow is 22°C;

[0174] (b) spraying 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 sodium carboxymethyl cellulose matrix and graphite powder doped in the sodium carboxymethyl cellulose matrix; wherein the doping amount of the graphite powder is 2%), and irradiating the material under sunlight at 25° C. for 60 min to evaporate the solution in the garbage leachate, thereby completing the drying of the garbage and obtaining a dried material with a water content of 37%.

[0175] S3, primary drying:

[0176] The dried material is transferred 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%;

[0177] The parameters of the primary drying include: using a steam tube rotary dryer; the heating medium is 180°C steam, and the discharge temperature of the primary dryer is 90°C.

[0178] S4, hot air separation:

[0179] The first dried material is separated by air separation using a horizontal air separator to obtain heavy matter and light matter respectively;

[0180] Among them, the air inlet of the horizontal air separator is rectangular in shape, the height of the air inlet is 500mm, the height of the center of the air inlet is 1550mm, and the wind temperature is 120°C; the wind direction of the air separation is 15°, and the wind speed is 20m / s.

[0181] S5, X-ray separation:

[0182] The heavy matter is subjected to X-ray separation to obtain organic matter and inert matter respectively, the X-ray separator comprises two electron X-ray sources, strong and weak, and two independent sensors with corresponding sensitivities; the organic matter comprises 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; the inert matter comprises any one of porcelain pieces, sand or stone, or a combination of at least two of them.

[0183] S6, Secondary Drying:

[0184] The light material obtained in S4 and the organic matter obtained in S5 are mixed and subjected to secondary drying in a fluidized bed dryer to obtain a second dried material, wherein the moisture content of the second dried material is 7%;

[0185] The temperature of the second drying material is 110°C; the heat source of the secondary drying is hot flue gas, and the temperature of the hot flue gas is 320°C.

[0186] S7. Baking:

[0187] The second dried material is transferred to a baking device and baked at 250°C for 30 minutes to obtain a baked material. The baking is carried out using a rotary drum baking machine. The baking heat carrier is circulating baking gas. The temperature of the circulating baking gas is 280°C.

[0188] S8, Cooling

[0189] The roasted material was cooled to 25° C. at a cooling rate of 5° C. / min, and cooled at this temperature for 50 min to catalyze the material, thereby obtaining a cooled roasted material.

[0190] S9, primary crushing and primary screening:

[0191] The cooled roasted material is subjected to primary crushing and primary screening in sequence, ensuring that the average processing rate of this process is 100 t / h; wherein the primary crushing and primary screening process includes:

[0192] (a) Feeding: The material enters the crusher through the feed port. The size of the feed port should be adapted to the specifications and output of the crusher.

[0193] (b) High-speed rotation: The rotor inside the crusher rotates at a high speed, and there are multiple hammers on the rotor. These hammers have a large linear velocity due to the high-speed rotation; wherein the rotation speed of the rotor inside the crusher is 1500rpm, and the linear velocity of the hammers is 70m / s;

[0194] (c) Impact crushing: After the material enters the crusher, it is impacted by the high-speed rotating hammer head and thus crushed. The impact force is the main force of crushing and can effectively crush the material. The impact force of the hammer head is 500N;

[0195] (d) Grinding effect: In addition to impact crushing, the material will also be subjected to grinding effect inside the crusher. This is because the material will rub and collide with the inner wall of the casing, the screen plate and the hammer head on the rotor during the crushing process;

[0196] (e) Particle size screening: The crushed material passes through a sieve plate with sieve holes of a certain size. The material larger than the sieve holes will be retained on the sieve plate for further crushing, while the material smaller than the sieve holes will be discharged through the sieve plate to become the finished product. Among them, the particle size of the sieve-surface material retained on the sieve plate is greater than 5mm (accounting for 26%); the particle size of the sieve-surface material discharged through the sieve plate is ≤5mm (accounting for 74%).

[0197] (f) Discharge: Finished materials are discharged from the discharge port, the size of which can be adjusted to control the size of the finished materials. Unqualified large particles may re-enter the crusher for re-crushing.

[0198] S10, secondary crushing and secondary screening:

[0199] The screened material is subjected to secondary crushing by a five-roll differential speed grinder, and then subjected to secondary screening to obtain improved biomass powder;

[0200] Wherein, the differential grinder 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 1:4:8; the speed of the low-speed roller is 25rpm; the differential grinder includes a cooling and forming roller group; the cooling and 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 1:1.18; the speed of the low-speed cooling roller is 30rpm; the temperature of the low-speed cooling roller is 17°C, and the temperature of the high-speed cooling roller is 19°C.

[0201] Example 4

[0202] This embodiment provides a process method for thermal sorting and upgrading of domestic waste. The difference from Embodiment 1 is that the sieve material obtained after the primary screening in S9 is subjected to eddy-electric separation and magnetic separation in sequence to separate the metal to obtain a coked material; the coked material is returned to the baking step of S7 for baking again, and the other steps are consistent with Embodiment 1.

[0203] Example 5

[0204] This embodiment provides a process method for hot sorting and upgrading of domestic waste. The difference from Embodiment 1 is that the screened material obtained after the primary screening in S9 is subjected to eddy-electric separation and magnetic separation in turn to separate the metal to obtain a coked material; the coked material is returned to the primary crushing step of S9 to be crushed again, and the other steps are consistent with Embodiment 1.

[0205] Example 6

[0206] This embodiment provides a process for hot sorting and quality improvement of domestic waste. The difference from Embodiment 1 is that no hydrogel is added during the drying process of step (b) of S2, and the drying process is performed in the following manner:

[0207] A heating pipe is set at the bottom of the garbage storage tank, and water vapor is introduced into the heating pipe. The flow rate of water vapor is set to 0.42m / s to ensure that the temperature of the garbage storage tank is maintained at 45±2°C. At the same time, the material is dried by sunlight. Under this condition, at least 24 hours of drying is required to reduce the water content of the dried material to 38%.

[0208] Example 7

[0209] This embodiment provides a process method for hot sorting and upgrading of domestic waste, which is different from Embodiment 1 in that, in S1, only one hydraulically driven rotor is provided, and the rotation speed of the hydraulically driven rotor is increased to 60 r / min, and the cutter heads fixed on the shafts of the two hydraulically driven rotors include: 10 groups of moving cutters facing each other, and a stationary cutter in the middle of each group of adjacent moving cutters spaced equidistantly;

[0210] The results show that: the domestic waste is fed into the coarse crusher through a grab bucket for coarse crushing, and crushed materials with a particle size ≤100mm and crushed materials with a particle size >100mm are obtained respectively. The crushed materials with a particle size >100mm are returned to the coarse crusher for coarse crushing again. The crushing needs to be repeated 7 times before the particle size of the materials obtained by coarse crushing can all be ≤100mm.

[0211] Example 8

[0212] This embodiment provides a process for hot sorting and quality improvement of domestic waste, which is different from the embodiment 1 in that the steps of ripening and dehydration are different, as shown below:

[0213] The crushed material is transferred to a garbage storage tank and aged for 6 days at 45°C to dehydrate, so that the leachate flows out of the garbage material; the first ventilation is carried out on the 1st to 3rd day, and the oxygen content in the wind flow is ensured to be 19%, and the ventilation rate is 0.35L·kg -1 DM·min -1 , the air flow temperature is 23℃; after the first ventilation, turn the material, and conduct the second ventilation on the 4th to 6th day, and ensure that the oxygen content in the air flow is 16%, and the ventilation rate is 0.25L·kg -1 DM·min -1 , the temperature of the wind flow is 26°C;

[0214] The results showed that after drying in the same step (b) as in Example 1, a dried material with a water content of 42% was obtained.

[0215] Example 9

[0216] This embodiment provides a process method for thermal sorting and upgrading of domestic waste. The difference from Embodiment 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 consistent with those of Embodiment 1); S6 uses a paddle dryer for secondary drying (the process parameters are consistent with those of Embodiment 1);

[0217] The results showed that the moisture content of the hydrophilic material in the first dried material was 32%, and the moisture content of the hydrophobic material was 7%; the average moisture content of the second dried material was 9%.

[0218] Example 10

[0219] This embodiment provides a process for hot sorting and upgrading of domestic waste. The difference from Embodiment 1 is that the primary crushing of S9 no longer uses a hammer crusher, but uses a low-speed coarse crusher for coarse crushing of S1 (the process parameters are the same as those of Embodiment 1), and then uses a sieve with an aperture of 5 mm for screening;

[0220] The results showed that the content of the particles with a diameter of more than 5 mm remaining on the sieve was as high as 82%, while the content of the particles discharged through the sieve was only 18%.

[0221] Embodiment 11

[0222] This embodiment provides a process for hot sorting and quality improvement of domestic waste. The difference from the embodiment 1 is that the setting of the differential roller group of the differential grinding machine in S10 and the secondary crushing is different from that in the embodiment 1, specifically:

[0223] The differential grinding machine comprises a differential roller set; wherein the differential roller set comprises 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 grinding machine comprises a cooling forming roller set;

[0224] The cooling forming roller group includes a cooling roller; the rotation speed of the cooling roller is 18 rpm; the temperature of the cooling roller is 15°C.

[0225] Comparative Example 1

[0226] This comparative example provides a process method for hot sorting and upgrading of domestic waste. The difference from Example 1 is that the S1 coarse crushing step is not performed, and the other settings are consistent with Example 1.

[0227] Comparative Example 2

[0228] This comparative example provides a process method for thermal sorting and upgrading of domestic waste. The difference from Example 1 is that step (a) of maturation and dehydration in S2 is not performed, and step (b) of drying is performed directly. Other settings are consistent with Example 1.

[0229] Comparative Example 3

[0230] This comparative example provides a process method for thermal sorting and upgrading of domestic waste. The difference from Example 1 is that the drying step (b) of step S2 is not performed, and the wet material obtained after maturation and dehydration in S1 is directly filtered through a filter screen, and the obtained wet material is directly subjected to primary drying. The other settings are consistent with Example 1.

[0231] Comparative Example 4

[0232] This comparative example provides a process method for thermal sorting and upgrading of domestic waste. The difference from Example 1 is that the S3 primary drying step is not performed, and the other settings are consistent with Example 1.

[0233] Comparative Example 5

[0234] This comparative example provides a process method for thermal sorting and upgrading of domestic waste. The difference from Example 1 is that the S6 secondary drying step is not performed, and the other settings are consistent with Example 1.

[0235] Comparative Example 6

[0236] This comparative example provides a process method for thermal sorting and quality improvement of domestic waste. The difference from Example 1 is that the S8 cooling step is not performed, and the other settings are consistent with Example 1.

[0237] Comparative Example 7

[0238] This comparative example provides a process method for hot sorting and upgrading of domestic waste. The difference from Example 1 is that the first-level crushing and first-level screening steps of S9 are not performed, and the other settings are consistent with Example 1.

[0239] Comparative Example 8

[0240] This comparative example provides a process method for hot sorting and upgrading of domestic waste. The difference from Example 1 is that the secondary crushing and secondary screening steps of S10 are not performed, and the other settings are consistent with Example 1.

[0241] Test Example 1

[0242] 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;

[0243] The test results are shown in Table 1 below:

[0244] Table 1

[0245]

[0246]

[0247] As shown in Table 1, the average particle size of the upgraded biomass powder prepared by the process of the present invention is 500-899 μm, and the specific surface area is 158-242 m 2 / g, energy density is 12.5-30.0MJ / kg, ash value is as low as below 15%, water content is as low as below 3%, and total yield is above 86.38%. This shows that the process method of the present invention bakes domestic waste at low temperature, recycles it, realizes carbonization of domestic waste, and prepares biomass powder with uniform component materials and high energy density, which can be further used for the preparation of green energy, enriching the back-end process route.

[0248] 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 it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, 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 ≤100mm; The crushed material is matured and dehydrated, and dried after the leachate flows out to obtain a dried material; 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 subjected to baking, cooling, primary crushing and primary screening 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 of ≤100mm and crushed materials with a particle size of >100mm. The crushed materials with a particle size of >100mm are returned to the coarse crusher for coarse crushing and screening again until the particle size of the obtained materials is ≤100mm. Preferably, the coarse crusher is a low-speed coarse crusher, and two hydraulic or motor-driven rotors are arranged in the crushing chamber of the low-speed coarse crusher; cutter heads are fixed on the shafts of the two hydraulic or motor-driven rotors; the fixed ends of the two hydraulically driven rotors are provided with double-row self-aligning roller bearings, and the following ends of the two hydraulically driven rotors are provided with two thrust self-aligning roller bearings; Preferably, 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 directions of rotation, and the speed of the first hydraulically driven rotor is 8-50 r / min, and the speed of the second hydraulically driven rotor is 10-50 r / min; the speeds of the first hydraulically driven rotor and the second hydraulically driven rotor are different, thereby tearing the material; Preferably, 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 set of adjacent moving cutters; Preferably, a screen is provided at the bottom of the coarse crusher, and the screen has a mesh size of 100 mm.

3. 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; Preferably, the specific steps of ripening include: The crushed materials are transferred to the garbage storage tank, and the first ventilation is carried out on the 1st to 3rd day, and the oxygen content in the wind flow is ensured to be 15-18%, and the ventilation rate is 0.2-0.3 L·kg -1 DM·min -1 , the air flow 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 0.3-0.4L·kg -1 DM·min -1 , the temperature of the wind flow is 22-25℃; Preferably, the drying includes heating drying and / or light drying; Preferably, the heating and drying is carried out through a heating pipe arranged at the bottom of the garbage storage tank, and the heating pipe is filled with water vapor and / or hot water; Preferably, the flow rate of water vapor and / or hot water in the heating pipe maintains the temperature in the storage tank at 40-80°C; Preferably, 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 material under sunlight to evaporate the solution in the garbage leachate, and completing the drying of the garbage; Preferably, the thickness of the hydrogel film is 0.1 to 1 mm; Preferably, 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 to 5% of the total mass of the hydrogel film; 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; Preferably, the photothermal material includes any one of graphene, carbon nanotubes, graphite powder or carbon black, or a combination of at least two of them.

4. The process for hot 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; Preferably, 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; Preferably, 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.

5. The process for hot sorting and upgrading of domestic waste according to claim 1 is 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, metal, glass, porcelain, wood or stone or a combination of at least two of them; Preferably, the air separation adopts a horizontal air separator; Preferably, the wind temperature of the horizontal air separator is 100-150°C; Preferably, the wind direction of the wind separation is 10-20°, and the wind speed of the wind separation is 8-20 m / s.

6. The process for hot sorting and upgrading of domestic waste according to claim 1 is 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; Wherein, 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 thereof; and / or, the inert matter includes any one of porcelain pieces, sand or stone, or a combination of at least two thereof; Preferably, the moisture content of the second dried material is 5-8%; Preferably, the temperature of the second drying material is 100-120°C; Preferably, 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; 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.

7. The process for hot sorting and upgrading of domestic waste according to claim 1 is characterized in that: The baking temperature is 210-250° C., and the baking time is 20-40 min. Preferably, the baking is carried out using a rotary drum baking machine; Preferably, the heat carrier used in the baking is circulating baking gas, and the temperature of the circulating baking gas is 250-300°C.

8. The process for hot sorting and upgrading of domestic waste according to claim 1 is characterized in that: The first-stage crushing adopts a hammer crusher; Preferably, 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; Preferably, the process method further 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.

9. The process for hot sorting and upgrading of domestic waste according to claim 1 is characterized in that: The secondary crushing adopts a five-roller differential speed grinding machine; Preferably, the differential grinding machine comprises a differential roller set; wherein the differential roller set comprises 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 15-30rpm; Preferably, 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 20~30rpm; the temperature of the low-speed cooling roller and the high-speed cooling roller is independently 10~20℃.

10. An improved biomass powder, characterized in that: The upgraded biomass powder is prepared by the process for upgrading the quality of domestic waste by thermal sorting as claimed in claim 1; Preferably, the particle size of the upgraded biomass powder is 500 to 899 μm; Preferably, the specific surface area of ​​the upgraded biomass powder is 158 to 242 m 2 / g; Preferably, the total moisture content of the upgraded biomass powder is ≤3%; Preferably, the ash value of the upgraded biomass powder is less than 15%; Preferably, the energy density of the upgraded biomass powder is 12.5 to 30 MJ / kg; Preferably, the gasification time for the upgraded biomass powder to be completely gasified at a temperature of 1300° C. is less than 7 seconds.

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