Household garbage resource recycling method and system

Abstract

The invention provides a household garbage resource recycling method and system, and the household garbage resource recycling method comprises the following steps: dehydrating household garbage to obtain dehydrated garbage; and the dehydrated garbage is subjected to screening treatment, and the light combustible is obtained. And the light combustible materials are subjected to drying treatment, and dry garbage is obtained. The dry garbage is subjected to anaerobic pyrolysis treatment, and carbon powder is obtained. Wherein pyrolysis non-condensable gas generated in the pyrolysis process is combusted to generate high-temperature flue gas which is used as heat for pyrolysis, and medium-temperature flue gas generated after pyrolysis is used for drying the light combustible materials. The light combustible materials are separated and extracted from the household garbage through a physical separation method, the carbon powder is prepared through anaerobic pyrolysis of a thermal chemical method, and the method is mild in condition, simple and easy to obtain, low in energy consumption and high in carbon powder recovery rate and has a good market prospect.

Description

Technical Field

[0001] This application relates to the technical field of resource recovery of domestic waste, and particularly relates to a method and system for resource recovery of domestic waste. Background Art

[0002] With the acceleration of the urbanization process, the generation amount of domestic waste increases year by year. How to effectively treat this waste has become a global environmental problem. At present, the treatment methods of domestic waste mainly include landfill, incineration, etc. However, these traditional methods have many deficiencies. For example, the landfill method occupies a large amount of land resources, and the incineration method has a high construction cost and a large carbon emission. Summary of the Invention

[0003] This application provides a method and system for resource recovery of domestic waste to solve at least some of the problems in the related technologies.

[0004] In a first aspect, an embodiment of this application provides a method for resource recovery of domestic waste, including:

[0005] Performing dehydration treatment on domestic waste to obtain dehydrated waste;

[0006] Performing screening treatment on the dehydrated waste to obtain light combustibles;

[0007] Performing drying treatment on the light combustibles to obtain dry waste;

[0008] Performing anaerobic pyrolysis treatment on the dry waste to obtain carbon powder; wherein, the heat generated by burning the non-condensable gas generated during pyrolysis is used as the heat for pyrolysis, and the medium-temperature flue gas generated after pyrolysis is used to dry the light combustibles.

[0009] Optionally, the performing screening treatment on the dehydrated waste to obtain light combustibles includes:

[0010] Performing crushing and primary magnetic separation treatment on the dehydrated waste to remove magnetic substances in the dehydrated waste and obtain first-stage treated waste;

[0011] Performing primary screening treatment on the first-stage treated waste to remove the undersize material and obtain the oversize material;

[0012] Performing secondary magnetic separation treatment on the oversize material to remove magnetic substances in the first-stage oversize material and obtain second-stage treated waste;

[0013] Performing secondary screening treatment on the second-stage treated waste to remove the undersize material and obtain the light combustibles.

[0014] Optionally, the primary screening of the first-stage treated waste includes: subjecting the first-stage treated waste to primary screening through a screening machine with a sieve plate, where the sieve plate is selected with a grading aperture, and the aperture range is 30 - 80 mm; and / or

[0015] The secondary screening of the second-stage treated waste includes: subjecting the second-stage treated waste to secondary screening through a winnowing machine, and the winnowing machine has multiple levels of wind force.

[0016] Optionally, the drying treatment of the light combustibles to obtain dry waste includes:

[0017] Subjecting the light combustibles to drying treatment through a drying system, and after drying, the moisture content of the dry waste is 8.0 - 18.0 wt%, and the material temperature is 80 - 150 °C.

[0018] Optionally, the anaerobic pyrolysis treatment of the dry waste includes:

[0019] Subjecting the dry waste to anaerobic pyrolysis treatment through a pyrolysis system to remove magnetic substances in the dehydrated waste. The pyrolysis temperature is 280 - 480 °C, the pyrolysis time is 40 - 240 min, and the internal cylinder working pressure of the pyrolysis system is within the range of +50 - +200 Pa of slightly positive pressure.

[0020] In a second aspect, an embodiment of the present application provides a domestic waste resource recovery system, including:

[0021] A dehydration system for dehydrating domestic waste to obtain dehydrated waste;

[0022] A screening system for screening the dehydrated waste to obtain light combustibles;

[0023] A drying system for drying the light combustibles to obtain dry waste;

[0024] A pyrolysis system for subjecting the dry waste to anaerobic pyrolysis treatment to obtain carbon powder; the pyrolysis system is connected to the drying system;

[0025] A gas furnace connected to the pyrolysis system;

[0026] Among them, the non-condensable gas generated during pyrolysis enters the gas furnace from the pyrolysis system to burn and generate high-temperature flue gas. The high-temperature flue gas enters the pyrolysis system from the gas furnace as heat for pyrolysis, and the medium-temperature flue gas generated after pyrolysis enters the drying system from the pyrolysis system to dry the light combustibles.

[0027] Optionally, the screening system includes:

[0028] A crusher for crushing the dewatered garbage.

[0029] A magnetic separator for removing magnetic substances from the dewatered garbage.

[0030] A screening machine and / or a winnowing machine for screening out light combustibles from the dewatered garbage; wherein, the screening machine includes one of a drum screen, a bouncing screen, and a vibrating screen, the screening machine has a sieve plate, and the sieve plate is selected with a grading aperture, and the aperture range is 30 - 80 mm; the winnowing machine has multiple levels of wind power.

[0031] Optionally, the dewatering system includes one of a vertical compressor, a horizontal compressor, a screw compressor, and a belt compressor; and / or

[0032] The drying system includes one of a pneumatic dryer and a fluidized bed dryer; and / or

[0033] The pyrolysis system includes a rotary kiln.

[0034] Optionally, the pyrolysis system includes a reactor, and a coke cleaning device is provided in the reactor for removing the carbon black layer attached to the inner wall of the reactor.

[0035] Optionally, it further includes a control system, which is electrically connected to the dewatering system, the screening system, the drying system, the pyrolysis system, and the gas furnace, and is used to control the operating parameters of the dewatering system, the screening system, the drying system, the pyrolysis system, and the gas furnace.

[0036] The domestic waste resource recovery method provided by this application uses a physical separation method to separate and extract light combustibles from domestic waste, and uses a thermochemical method for oxygen-free pyrolysis to prepare carbon powder. The above methods are all mild in conditions, simple and easy to obtain, low in energy consumption, and high in carbon powder recovery rate, and have good market prospects.

[0037] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit this application. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The accompanying drawings here are incorporated into the specification and constitute a part of this specification, showing the embodiments consistent with this application, and are used together with the specification to explain the principles of this application.

[0039] Figure 1 Shown is a flowchart of the domestic waste resource recovery method according to an exemplary embodiment of this application;

[0040] Figure 2 Shown is a flowchart of the domestic waste resource recovery method according to another exemplary embodiment of this application;

[0041] Figure 3 The following is a block diagram of a domestic waste resource recovery system according to an exemplary embodiment of the present application;

[0042] Figure 4 The following is a block diagram of a domestic waste resource recovery system according to another exemplary embodiment of the present application;

[0043] Figure 5 The following is a schematic diagram of a domestic waste resource recovery system and method according to an exemplary embodiment of the present application. Detailed implementation manners

[0044] Here, the exemplary embodiments will be described in detail, and the examples are shown in the drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementation manners described in the following exemplary embodiments do not represent all implementation manners consistent with the present application. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0045] To better understand the technical solution of the present application, the domestic waste resource recovery method and system of the present application will be described in detail below with reference to the drawings. Without conflict, the features in the following embodiments and implementation manners can be combined with each other.

[0046] See Figure 1 As shown, an embodiment of the present application provides a domestic waste resource recovery method, including steps S1 - S4:

[0047] Step S1, dehydrate the domestic waste to obtain dehydrated waste. Compress and dehydrate the domestic waste, and extrude the water in the domestic waste by applying an external force to reduce the water content of the domestic waste. Optionally, a vertical compressor, a horizontal compressor, a screw compressor, a belt compressor or other compression dehydration equipment can be selected as the dehydration system to reduce the water content of the domestic waste.

[0048] Step S2, screen the dehydrated waste to obtain light combustibles. Extract the light combustibles from the dehydrated waste through screening.

[0049] Step S3, dry the light combustibles to obtain dry waste. After drying, further reduce the water content and weight of the light combustibles.

[0050] Step S4, perform anaerobic pyrolysis on the dry waste to obtain carbon powder. Among them, the pyrolysis non - condensable gas generated during pyrolysis is burned to generate high - temperature flue gas as the heat for pyrolysis, and the medium - temperature flue gas generated after pyrolysis is used to dry the light combustibles.

[0051] In domestic waste, light combustibles (such as plastics, paper, etc.) account for a large proportion and have a relatively high calorific value. By extracting and effectively utilizing them, not only can the volume and weight of the waste be reduced, the treatment cost be lowered, but also they can be converted into clean resources, realizing the resource utilization of the waste. As a method for treating organic solid waste, the pyrolysis technology has the advantages of high treatment efficiency, low pollution, high resource recovery rate, etc., and can convert light combustibles into carbon powder. As an important industrial raw material, carbon powder has wide applications in the fields of metallurgy, chemical industry, environmental protection, etc. Therefore, through the above technical solutions, the light combustibles in domestic waste can be extracted and converted into carbon powder through pyrolysis technology, realizing the resource recovery of biochemical waste.

[0052] The domestic waste resource recovery method provided by this application uses a physical separation method to separate and extract light combustibles from domestic waste, and uses a thermochemical method for oxygen-free pyrolysis to prepare carbon powder. The above methods are all mild in conditions, simple and easy to obtain, low in energy consumption, and high in carbon powder recovery rate, and have good market prospects. Based on the effective treatment and resource utilization of domestic waste, this application aims to achieve the efficient conversion and energy reuse of domestic waste through innovative processes for extracting light combustibles from domestic waste and pyrolysis, providing new solutions for the environmental protection and energy fields.

[0053] See Figure 2 As shown, in some optional embodiments, in step S2, the step of screening the dehydrated waste to obtain light combustibles may further include steps S21 - S24:

[0054] In step S21, the dehydrated waste is crushed and subjected to primary magnetic separation to remove magnetic substances in the dehydrated waste, obtaining first-stage treated waste. Crushing the dehydrated waste releases the waste in the membrane bag to ensure that the waste in the membrane bag can be effectively released, which is beneficial to the subsequent recovery of light combustibles. Then, magnetic separation technology is used to recover the magnetic substances therein, realizing resource reuse. Optionally, a crusher can be selected for crushing treatment, and a suspended magnetic separator that can be installed above the conveyor belt can be selected as the magnetic separation equipment for magnetic separation treatment.

[0055] In step S22, the first-stage treated waste is subjected to primary screening to remove the undersize, obtaining the oversize. Through screening treatment, the undersize is removed to separate the light oversize.

[0056] In step S23, the oversize is subjected to secondary magnetic separation to remove magnetic substances in the first-stage oversize, obtaining second-stage treated waste. Secondary magnetic separation is carried out to further recover the possibly remaining magnetic substances using magnetic separation technology.

[0057] Step S24: Perform secondary screening on the second-stage treated waste, remove the undersize material, and obtain the light combustibles. By performing secondary screening, the light combustibles can be further refined and extracted, thus achieving efficient separation of the light combustibles in domestic waste.

[0058] Among them, in the above step S21, the primary screening of the first-stage treated waste may include: performing primary screening on the first-stage treated waste through a screening machine with a sieve plate, and the sieve plate is selected with a grading aperture, and the aperture range is 30-80 mm. It can be understood that after the domestic waste is bag-broken and screened, the sieve plate of the screening machine can be set with graded and segmented screening apertures, and the aperture range can be set to 30-80 mm to ensure effective removal of heavy inorganic substances in the waste. Optionally, screening equipment such as a drum screen, a bouncing screen, or a vibrating screen can be selected as the screening machine.

[0059] In the above step S24, the secondary screening of the second-stage treated waste may include: performing secondary screening on the second-stage treated waste through a winnowing machine, and the winnowing machine has multiple levels of wind power. In this way, the second-stage treated waste after secondary magnetic separation enters the winnowing system to winnow and extract the light combustibles therein. Optionally, a three-stage horizontal wind power winnowing machine can be selected as the winnowing equipment. Materials with different specific gravities in domestic waste are diverted in three directions under the action of wind, and the light combustibles enter the conveyor belt of the rear duct and are discharged. The winnowing rate of the light combustibles can reach 80-90%.

[0060] In some alternative embodiments, in the above step S3, the drying treatment of the light combustibles to obtain dry waste may include: drying the light combustibles through a drying system, and the moisture content of the dry waste after drying is 8.0-18.0 wt%, and the material temperature is 80-150 °C. Among them, the light combustibles can enter the material drying system through the plant conveyor belt. Optionally, a drying machine such as a pneumatic dryer or a fluidized bed dryer can be selected for the drying system, and the high-moisture-content light combustibles are heated and dried by means of wall heating. After drying, the moisture content of the dry waste is 8.0-18.0 wt%, and the temperature of the dried material is controlled at 80-150 °C.

[0061] In some alternative embodiments, in step S4 above, the anaerobic pyrolysis treatment of the dry waste may include: subjecting the dry waste to anaerobic pyrolysis treatment through a pyrolysis system to obtain carbon powder. The pyrolysis temperature is 280 - 480 °C, the pyrolysis time is 40 - 240 min, and the working pressure inside the inner cylinder of the pyrolysis system is within the range of +50 to +200 Pa of slightly positive pressure. Optionally, a pyrolysis furnace such as a rotary kiln can be used as the pyrolysis system. The pyrolysis temperature of the light combustibles is controlled at 280 - 480 °C, and the pyrolysis time is controlled at 40 - 240 min. The pyrolysis furnace uses flexible thermal sealing technology to achieve stable sealing under continuous feeding and discharging, and controls the working pressure inside the inner cylinder of the pyrolysis furnace to always be stable within the range of +50 to +200 Pa of slightly positive pressure, avoiding the inhalation of oxygen-containing air and ensuring that the reaction is controlled under anaerobic conditions.

[0062] Furthermore, the pyrolysis system may include a reactor, and an on-line coke cleaning device can be arranged inside the reactor, which avoids the attachment of a carbon black layer with good heat insulation properties formed during the pyrolysis process of the waste material on the inner wall of the reactor, and does not affect the problem of heat transfer from the high-temperature pyrolysis flue gas in the outer jacket of the reactor to the waste material inside the reactor through the partition wall, nor does it affect the heat transfer efficiency between the high-temperature pyrolysis flue gas and the material.

[0063] In some alternative embodiments, in step S4 above, the non-condensable gas generated during pyrolysis is combusted to generate high-temperature flue gas, and the high-temperature flue gas is used as the heat for pyrolysis; the medium-temperature flue gas obtained by cooling the high-temperature flue gas after pyrolysis is used to dry the light combustibles. It can be understood that the pyrolysis oil and gas generated by the pyrolysis system are sent into a gas furnace through a pipeline, mixed with the combustion-supporting air distributed at multiple points and combusted to generate high-temperature flue gas, and then the high-temperature flue gas is sent back to the pyrolysis system through a pipeline as the heat for pyrolysis to provide a heat source for the pyrolysis treatment. Furthermore, the medium-temperature flue gas generated by the pyrolysis system can be sent into the drying system as a heat source for drying the light combustibles. The low-temperature flue gas generated by the drying system is discharged after being treated.

[0064] In some alternative embodiments, the above steps such as dehydration treatment, screening treatment, magnetic separation treatment, air separation treatment, drying treatment, anaerobic pyrolysis treatment, etc., as well as the dehydration equipment, crusher, magnetic separator, screening machine, air separator, dryer, pyrolysis furnace, etc. used in each step, can all adopt a computer control system (abbreviated as DCS control system) based on PLC and upper computer with advanced technology and reliable performance to centrally monitor, operate and decentralizedly control the various equipment and machines on the production line. Moreover, the operating parameters of the above steps, including crushing particle size, screening aperture ratio, air separation rate, drying temperature and time, pyrolysis temperature and pyrolysis time, etc., can all be optimized to improve the extraction efficiency of the light combustibles and the quality of the pyrolysis carbon powder.

[0065] See Figure 3As shown in the figure, an embodiment of the present application provides a domestic waste resource recovery system for implementing the domestic waste resource recovery method described in the above embodiments and implementation manners. The domestic waste resource recovery system may include:

[0066] A dehydration system 10 for dehydrating domestic waste to obtain dehydrated waste. In this way, the domestic waste is compressed and dehydrated by the dehydration system 10, and the water in the domestic waste is squeezed out by applying an external force to reduce the water content of the domestic waste. Optionally, the dehydration system 10 includes one of a vertical compressor, a horizontal compressor, a screw compressor, and a belt compressor. That is, a compression dehydration device such as a vertical compressor, a horizontal compressor, a screw compressor, or a belt compressor can be selected as the dehydration system 10 to reduce the water content of the domestic waste.

[0067] A screening system 20 for screening the dehydrated waste to obtain light combustibles. Through the screening of the screening system 20, light combustibles are extracted from the dehydrated waste. It should be noted that both the dehydration system 10 and the screening system 20 can be connected to a photocatalytic deodorization device, and during the dehydration treatment and screening treatment, further deodorization optimization treatment of the garbage odor can be realized.

[0068] A drying system 30 for drying the light combustibles to obtain dry waste. After the drying treatment by the drying system 30, the water content and weight of the light combustibles are further reduced. By drying the light combustibles through the drying system, the water content of the dry waste after drying is 8.0 - 18.0 wt%, and the material temperature is 80 - 150 °C. Among them, the light combustibles can enter the material drying system through the factory conveyor belt. Optionally, the drying system 30 includes one of a pneumatic dryer and a fluidized bed dryer. That is, the drying system can select a pneumatic dryer, a fluidized bed dryer, etc. Optionally, the drying system can select dryers such as a pneumatic dryer and a fluidized bed dryer, and adopt the method of indirect wall heating to realize the heating and drying of light combustibles with high water content.

[0069] A pyrolysis system 40 for carrying out anaerobic pyrolysis treatment on the dry waste to obtain carbon powder. The pyrolysis system 40 is connected to the drying system 30. By carrying out anaerobic pyrolysis treatment on the dry waste through the pyrolysis system 40, carbon powder is obtained. Optionally, the pyrolysis system 40 includes a rotary kiln, that is, the pyrolysis system 40 can adopt a pyrolysis furnace such as a rotary kiln. The pyrolysis temperature of the light combustibles is controlled at 280 - 480 °C, and the pyrolysis time is controlled at 40 - 240 min. The pyrolysis furnace realizes stable sealing under continuous feeding and discharging through flexible thermal sealing technology, and controls the working pressure of the inner cylinder of the pyrolysis furnace to be always stable within the range of +50 - +200 Pa of slightly positive pressure, avoiding the inhalation of oxygen-containing air, and ensuring that the reaction is controlled under anaerobic conditions.

[0070] A gas furnace 50 is connected to the pyrolysis system 40. During pyrolysis, the non-condensable gas generated enters the gas furnace 50 from the pyrolysis system 40 and burns to produce high-temperature flue gas. The high-temperature flue gas enters the pyrolysis system 40 from the gas furnace 50 as heat for pyrolysis. The medium-temperature flue gas generated after pyrolysis enters the drying system 30 from the pyrolysis system 40 to dry the light combustibles. It can be understood that the pyrolysis oil and gas generated by the pyrolysis system 40 are sent into the gas furnace 50 through a pipeline, mixed with the combustion-supporting air distributed at multiple points and burned to produce high-temperature flue gas, and then the high-temperature flue gas is sent back to the pyrolysis system 40 through a pipeline as heat for pyrolysis to provide heat for pyrolysis treatment. Further, the medium-temperature flue gas generated by the pyrolysis system 40 can be sent into the drying system 30 as a heat source to dry the light combustibles. The low-temperature flue gas generated by the drying system 30 is discharged after treatment.

[0071] In domestic waste, light combustibles (such as plastics, paper, etc.) account for a large proportion and have a high calorific value. By extracting and effectively utilizing them, not only can the volume and weight of the waste be reduced, the treatment cost be lowered, but also they can be converted into clean resources to achieve the resource utilization of waste. As a method for treating organic solid waste, pyrolysis technology has the advantages of high treatment efficiency, low pollution, high resource recovery rate, etc., and can convert light combustibles into carbon powder. As an important industrial raw material, carbon powder has a wide range of applications in the fields of metallurgy, chemical industry, environmental protection, etc. Therefore, through the above technical solutions, the light combustibles in domestic waste can be extracted and converted into carbon powder by pyrolysis technology, realizing the resource recovery of biochemical waste.

[0072] The domestic waste resource recovery system provided by this application uses physical separation methods to separate and extract light combustibles from domestic waste, and uses thermochemical methods for oxygen-free pyrolysis to prepare carbon powder. The above methods are all mild in conditions, simple and easy to obtain, low in energy consumption, and high in carbon powder recovery rate, with good market prospects. Based on the effective treatment and resource utilization of domestic waste, this application aims to achieve the efficient conversion and energy reuse of domestic waste through innovative processes for extracting light combustibles and pyrolysis from domestic waste, providing new solutions for the environmental protection and energy fields.

[0073] In some alternative embodiments, the screening system 20 includes:

[0074] A crusher for crushing the dewatered waste.

[0075] A magnetic separator for removing magnetic substances from the dewatered waste. Optionally, a suspended magnetic separator that can be installed above the conveyor belt can be selected as the magnetic separation equipment for magnetic separation treatment.

[0076] A screening machine and a winnowing machine are used to screen out light combustibles from the dewatered garbage. Among them, the screening machine includes one of a drum screen, a bounce screen, and a vibrating screen. That is, screening equipment such as a drum screen, a bounce screen, and a vibrating screen can be selected as the screening machine. The screening machine has a sieve plate, and the sieve plate is selected with a grading aperture, and the aperture range is 30-80 mm. The winnowing machine has multiple levels of wind power. Optionally, a three-stage horizontal wind power winnowing machine can be selected as the winnowing equipment.

[0077] Optionally, after domestic waste is dewatered, the dewatered garbage can be crushed and subjected to primary magnetic separation treatment by a crusher and a magnetic separator to remove magnetic substances in the dewatered garbage and obtain first-stage treated garbage. Then, the first-stage treated garbage is subjected to primary screening treatment by a screening machine to remove the undersize material and obtain the oversize material, ensuring the effective removal of heavy inorganic substances in the garbage. Then, the oversize material is subjected to secondary magnetic separation treatment by a magnetic separator to remove magnetic substances in the first-stage oversize material and obtain second-stage treated garbage. Then, the second-stage treated garbage is subjected to secondary screening treatment by a winnowing machine to remove the undersize material and obtain the light combustibles.

[0078] It can be understood that after domestic waste is dewatered, it can first be crushed by a crusher to release the garbage in the membrane bag to ensure the effective release of the garbage in the membrane bag, which is beneficial to the subsequent recovery of light combustibles. Then, the magnetic separation technology of the magnetic separator is used to recover the magnetic substances therein to realize resource reuse. After being screened by a screening machine to remove the undersize material, the light oversize material is separated. Then, it undergoes secondary magnetic separation by a magnetic separator to further recover the magnetic substances that may remain by using the magnetic separation technology. Then, after undergoing secondary screening treatment by a winnowing machine, materials with different specific gravities in domestic waste are diverted in three directions under the action of wind. The light combustibles enter the rear air duct conveyor belt and are discharged. The winnowing rate of the light combustibles can reach 80-90%, and the light combustibles are further refined and extracted, thus realizing the efficient separation of light combustibles in domestic waste.

[0079] In some alternative embodiments, the pyrolysis system 40 may include a reactor, and a coke cleaning device is provided in the reactor for removing the carbon black layer adhering to the inner wall of the reactor. It can be understood that an on-line coke cleaning device can be arranged in the reactor, which avoids the problem that the carbon black layer with good heat insulation properties formed during the pyrolysis process of the garbage material adheres to the inner wall of the reactor, does not affect the problem of the heat transfer of the high-temperature pyrolysis flue gas between the outer jacket of the reactor to the garbage material in the reactor through the partition wall, and does not affect the heat transfer efficiency between the high-temperature pyrolysis flue gas and the material.

[0080] See Figure 4As shown, in some alternative embodiments, the domestic waste resource recovery system may further include a control system 60, which is electrically connected to the dehydration system 10, the screening system 20, the drying system 30, the pyrolysis system 40, and the gas furnace 50, and is used to control the operating parameters of the dehydration system 10, the screening system 20, the drying system 30, the pyrolysis system 40, and the gas furnace 50. Optionally, the control system 60 may adopt a computer control system (abbreviated as DCS control system) based on PLC and upper computer with advanced technology and reliable performance.

[0081] It can be understood that for the above steps such as dehydration treatment, screening treatment, magnetic separation treatment, air separation treatment, drying treatment, and anaerobic pyrolysis treatment, as well as the dehydration equipment, crushers, magnetic separators, screening machines, air separators, dryers, pyrolysis furnaces, etc. used in each step, the DCS control system can be adopted to centrally monitor, operate, and disperse control the various equipment and machines on the production line. And the operating parameters of the above steps, including crushing particle size, screening aperture ratio, air separation rate, drying temperature and time, pyrolysis temperature and pyrolysis time, etc., can be optimized to improve the extraction efficiency of light combustibles and the quality of pyrolytic carbon powder.

[0082] See Figures 1 to 5 As shown, the domestic waste resource recovery method and system provided by the embodiments of the present application can extract light combustibles from domestic waste and synergistically prepare carbon powder by pyrolysis. The steps processed by the dehydration system 10 and the screening system 20 can be regarded as the light combustible extraction section (abbreviated as section one), and the steps processed by the drying system 30 and the pyrolysis system 40 can be regarded as the section for pyrolytic preparation of carbon powder from light combustibles (abbreviated as section two).

[0083] In section one, for the extraction of light combustibles: First, the domestic waste is compressed and dehydrated by the dehydration system to effectively reduce its moisture content. Then, the dehydrated waste is crushed by a crusher to release the waste in the membrane bag, and the magnetic separation technology of the magnetic separator is used to recover the magnetic substances therein. Subsequently, through the screening treatment of the screening machine, the light oversize materials are separated, and the undersize materials are recycled to the storage bin. Then, secondary magnetic separation is carried out by the magnetic separator to further recover the possibly remaining magnetic substances. Finally, through the air separation technology of the air separator, the light combustibles are further finely extracted. The oversize materials are stored as light combustibles in the light combustible storage tank, and the undersize materials are recycled to the storage bin, thereby realizing the efficient separation of light combustibles from domestic waste.

[0084] In the second section, pyrolysis is used to prepare carbon powder: the light combustibles extracted in the first section are sent to the drying system for drying. The dried light combustibles are then sent to the pyrolysis system for low-temperature pyrolysis to prepare carbon powder. The heat source for the pyrolysis treatment can be provided by the pyrolysis non-condensable gas generated by the pyrolysis system. The pyrolysis non-condensable gas burns in the gas furnace to produce high-temperature flue gas, which can enter the pyrolysis system and be used for heat for pyrolysis of light combustibles. The medium-temperature flue gas after pyrolysis can enter the drying system for drying light combustibles. The low-temperature flue gas after drying is treated and discharged out of the drying system to meet the standards.

[0085] The following are two embodiments of the method and system for recycling domestic waste provided by the embodiments of the present application:

[0086] Example 1, taking a domestic waste treatment project in southern Hebei as an example, the production line processes 450 tons of domestic waste per day. The project first crushes the garbage through a crusher, and then uses a magnetic separator to recover the magnetic material. Next, the domestic waste is screened through a drum screen, and the sieve plates are graded. The apertures are divided into two types: 30mm and 50mm. The front 3 / 5 is 30mm, and the rear 2 / 5 is 50mm. Subsequently, the screened material is sent to the air separator for air separation. The air separator adopts a three-stage sorting mode. After the screened material is air-separated, the magnetic material is further separated by a magnetic separator. Under the condition of stable operation of the equipment, 25-35wt% of light combustibles can be separated from domestic waste. The above-mentioned light combustibles were then moved to the laboratory for subsequent testing. First, the light combustibles were dried (the moisture content was controlled at 10wt%), and then moved into the pyrolysis system for anaerobic pyrolysis. Under the reaction conditions of 300°C pyrolysis temperature and 60min reaction time, the calorific value of the collected pyrolysis non-condensable gas was tested to be 30 (1±5%) MJ / kg, and the calorific value of the obtained pyrolysis carbon was tested to be 18 (1±10%) MJ / kg.

[0087] Example 2: Taking a domestic waste treatment project in a certain place in southern Hebei as an example, the daily treatment capacity of this production line is 450 tons of domestic waste. First, the waste is crushed by a crusher, and then a magnetic separator is used to recover magnetic substances. Next, the domestic waste is screened by a vibrating screen. The sieve plates are classified, and the aperture sizes are of two types: 30 mm and 50 mm. The front 3 / 5 is 30 mm, and the rear 2 / 5 is 50 mm. Subsequently, the oversize is sent to a winnower for winnowing. The winnower adopts a three-stage separation mode. After the oversize is winnowed, a magnetic separator is used to further separate magnetic substances. Under the condition of stable operation of the equipment, 25 - 35 wt% of light combustibles can be separated from the domestic waste. Subsequently, the above-mentioned light combustibles are transferred to the laboratory for subsequent tests. First, the light combustibles are dried (the moisture content is controlled at 10 wt%), and then transferred to a pyrolysis system for anaerobic pyrolysis. Under the conditions of a pyrolysis temperature of 450 °C and a reaction time of 90 min, the calorific value of the non-condensable gas obtained by pyrolysis is tested to be 25(1 ± 5%) MJ / kg, and the calorific value of the pyrolytic carbon obtained is tested to be 15(1 ± 10%) MJ / kg.

[0088] It should be understood that the present application is not limited to the precise structures that have been described above and shown in the drawings, and various modifications and changes can be made without departing from its scope. The scope of the present application is only limited by the appended claims.

Claims

1. A method for recycling domestic waste, characterized in that: include: Dehydrating the domestic waste to obtain dehydrated waste; Screening the dehydrated garbage to obtain light combustibles; Drying the light combustibles to obtain dry garbage; The dry garbage is subjected to anaerobic pyrolysis treatment to obtain carbon powder; wherein, the pyrolysis non-condensable gas generated during the pyrolysis process is burned to generate high-temperature flue gas as heat for pyrolysis, and the medium-temperature flue gas generated after the pyrolysis is used to dry the light combustibles.

2. The method for recycling domestic waste according to claim 1, characterized in that: The dehydrated garbage is screened to obtain light combustibles, including: The dehydrated garbage is crushed and subjected to a magnetic separation treatment to remove magnetic substances in the dehydrated garbage to obtain first-stage processed garbage; The first-stage processed garbage is subjected to a screening process to remove the undersize matter and obtain the oversize matter; The oversize material is subjected to secondary magnetic separation treatment to remove magnetic substances in the first-stage oversize material to obtain second-stage treated garbage; The second-stage treated waste is subjected to secondary screening treatment to remove the undersize material to obtain the light combustible material.

3. The method for recycling domestic waste according to claim 2, characterized in that: The first-stage processed garbage is subjected to a screening process, comprising: the first-stage processed garbage is subjected to a screening process by a screening machine having a screening plate, wherein the screening plate has a graded aperture, and the aperture range is 30 to 80 mm; and / or The second-stage processed garbage is subjected to secondary screening treatment, comprising: the second-stage processed garbage is subjected to secondary screening treatment by a winnowing machine, wherein the winnowing machine has multiple levels of wind force.

4. The method for recycling domestic waste according to claim 1, characterized in that: The step of drying the light combustibles to obtain dry garbage comprises: The light combustibles are dried by the drying system, and after drying, the moisture content of the dry garbage is 8.0-18.0wt%, and the material temperature is 80-150°C.

5. The method for recycling domestic waste according to claim 1, characterized in that: The step of subjecting the dry garbage to anaerobic pyrolysis treatment comprises: The dry garbage is subjected to anaerobic pyrolysis treatment through a pyrolysis system to remove magnetic substances in the dehydrated garbage. The pyrolysis temperature is 280-480°C, the pyrolysis time is 40-240 minutes, and the inner cylinder working pressure of the pyrolysis system is within the micro-positive pressure range of +50-+200Pa.

6. A system for recycling domestic waste, characterized in that: include: A dehydration system, used for dehydrating domestic waste to obtain dehydrated waste; A screening system, used for screening the dehydrated garbage to obtain light combustibles; A drying system, used for drying the light combustibles to obtain dry garbage; A pyrolysis system, used for subjecting the dry garbage to anaerobic pyrolysis to obtain carbon powder; The pyrolysis system is in communication with the drying system; a gas furnace, connected to the pyrolysis system; Among them, the pyrolysis non-condensable gas generated during the pyrolysis process enters the gas furnace from the pyrolysis system to burn and produce high-temperature flue gas. The high-temperature flue gas enters the pyrolysis system from the gas furnace as heat for pyrolysis. The medium-temperature flue gas generated after pyrolysis enters the drying system from the pyrolysis system to dry the light combustible material.

7. The system for recycling domestic waste according to claim 6, characterized in that: The screening system comprises: A crusher, used for crushing the dehydrated garbage; A magnetic separator for removing magnetic substances from the dehydrated garbage; The screening machine and the air separator are used to screen the dehydrated garbage to obtain light combustibles; wherein the screening machine includes one of a drum screen, a bouncing screen, and a vibrating screen, and the screening machine has a screen plate, and the screen plate has a graded aperture with an aperture range of 30 to 80 mm; the air separator has multi-level wind force.

8. The system for recycling domestic waste according to claim 7, characterized in that: The dehydration system comprises one of a vertical compressor, a horizontal compressor, a screw compressor, and a belt compressor; and / or The drying system comprises one of an air flow dryer and a fluidized bed dryer; and / or The pyrolysis system includes a rotary kiln.

9. The system for recycling domestic waste according to claim 6, characterized in that: The pyrolysis system comprises a reactor, wherein a coke removal device is arranged in the reactor for removing the carbon black layer attached to the inner wall of the reactor.

10. The system for recycling domestic waste according to claim 6, characterized in that: It also includes a control system, which is electrically connected to the dehydration system, the screening system, the drying system, the pyrolysis system and the gas furnace, and is used to control the operating parameters of the dehydration system, the screening system, the drying system, the pyrolysis system and the gas furnace.

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