System and method for treating solid waste

Abstract

The invention discloses a system and method for treating solid waste. The system comprises a pretreatment unit, a drying unit, a pyrolysis unit and a screening unit. The pyrolysis unit comprises: an inner cylinder and an outer cylinder. The inner cylinder can be rotatably arranged to form a pyrolysis space in the inner cylinder. The inner wall of the inner cylinder is provided with spiral blades. The front end of the inner cylinder is provided with a dry material inlet, and the rear end of the inner cylinder is provided with a solid material outlet. The outer cylinder is sleeved on the inner cylinder to form a combustion space. The combustion space is provided with a pyrolysis oil and gas pipeline. One end of the pyrolysis oil and gas pipeline is connected with the pyrolysis space, and the other end of the pyrolysis oil and gas pipeline extends in the combustion space. A primary air inlet and a secondary air inlet are provided on the outer cylinder near the other end of the pyrolysis oil and gas pipeline. The secondary air inlet and the other end of the pyrolysis oil and gas pipeline are staggered. A heat exchange flue gas outlet is provided on the outer cylinder away from the other end of the pyrolysis oil and gas pipeline. The heat exchange flue gas outlet and the drying cold air outlet are connected with the drying hot air inlet.

Description

Technical Field

[0001] The present invention belongs to the technical field of solid waste utilization, and in particular relates to a system and method for treating solid waste. Background Art

[0002] Anaerobic pyrolysis of solid organic waste has good effects in reducing solid waste, making it harmless and recycling it, and is considered to be a promising way to dispose of solid organic waste. The biochar produced by pyrolysis has the advantages of large specific surface area and high porosity, and is a relatively good building material and soil conditioner with broad application prospects. The utilization of pyrolysis oil and gas is relatively complex. Currently, the commonly used methods are: (1) directly entering the burner for combustion after leaving the furnace to produce flue gas, which is then recycled to the system; (2) washing and purifying in a water washing tower after leaving the furnace, and then separating oil and water to prepare clean fuels and chemicals. However, the current utilization methods still have certain technical barriers in the process of industrial application, such as: (1) tar condensation is prone to occur during direct reuse, blocking pipelines and burners, and causing unstable combustion process; (2) washing and then burning or preparing other chemicals has a higher added value, but produces a large amount of dusty and oily wastewater, which is difficult to separate oil and water and difficult to reuse tar.

[0003] Therefore, the existing solid waste pyrolysis technology needs to be improved. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems in the related art to a certain extent. To this end, one purpose of the present invention is to provide a system and method for treating solid waste, which not only effectively solves the problem of difficult pipe coking or oily wastewater caused by water washing during the pyrolysis stage of the existing solid waste treatment process, but also realizes the resource utilization of organic solid waste and reduces costs.

[0005] In one aspect of the present invention, the present invention provides a system for treating solid waste. According to an embodiment of the present invention, the system comprises:

[0006] A pretreatment unit, wherein the pretreatment unit has a solid waste inlet, an inorganic material outlet, and an organic material outlet;

[0007] A drying unit, wherein the drying unit has an organic material inlet, a dry hot air inlet, a dry material outlet and a dry cold air outlet, and the organic material inlet is connected to the organic material outlet;

[0008] A pyrolysis unit, the pyrolysis unit comprising:

[0009] An inner cylinder, wherein the inner cylinder is rotatably arranged, a pyrolysis space is formed inside the inner cylinder, and spiral blades are arranged on the inner wall of the inner cylinder, and a dry material inlet is arranged at the front end of the inner cylinder, and the dry material inlet is connected to the dry material outlet through a feed spiral, and a solid material outlet is arranged at the rear end of the inner cylinder;

[0010] An outer cylinder, wherein the outer cylinder is sleeved on the inner cylinder, and a combustion space is formed between the inner cylinder and the outer cylinder, wherein a pyrolysis oil and gas pipeline is provided in the combustion space, wherein one end of the pyrolysis oil and gas pipeline is communicated with the pyrolysis space, and the other end of the pyrolysis oil and gas pipeline extends in the combustion space, and a primary air inlet and a secondary air inlet are provided on the outer cylinder near the other end of the pyrolysis oil and gas pipeline, and the secondary air inlet is staggered with the other end of the pyrolysis oil and gas pipeline, and a heat exchange flue gas outlet is provided on the outer cylinder away from the other end of the pyrolysis oil and gas pipeline, and the heat exchange flue gas outlet and the dry cold air outlet are connected to the dry hot air inlet;

[0011] A screening device is provided, wherein the screening device has a solid material inlet, a pyrolytic carbon outlet and a solid waste outlet, and the solid material inlet is connected to the solid material outlet via a spiral discharging machine provided with a cooling jacket.

[0012] The system for treating solid waste according to an embodiment of the present invention supplies solid waste to a pretreatment unit to remove large pieces of metal and other materials that cause the screw conveyor to be entangled / stuck, and then dries the obtained organic material in a drying unit and sends it to the inner cylinder of a pyrolysis unit for pyrolysis. As the inner cylinder rotates, the dry material therein is tumbled, so that the heating surface of the material is uniform, and at the same time, the spiral blades on the inner wall of the inner cylinder continuously push the material in the inner cylinder forward, and an outer cylinder is sleeved on the inner cylinder, and a pyrolysis oil and gas pipeline is arranged in a combustion space formed between the inner cylinder and the outer cylinder. One end of the pyrolysis oil and gas pipeline is connected to the pyrolysis space in the inner cylinder, and the other end extends in the combustion space, and a primary air inlet and a secondary air inlet are provided in the outer cylinder near the other end of the pyrolysis oil and gas pipeline. The air inlet, that is, the pyrolysis oil and gas generated by the pyrolysis of the cylinder in the pyrolysis unit is introduced into the combustion space through the pyrolysis oil and gas pipeline to be mixed with the primary air for combustion. The combustion flue gas generated by the combustion is matched with the secondary air to provide a heat source for the pyrolysis reaction in the inner cylinder. The heat exchange flue gas obtained after heat exchange is matched with a part of the dry cold air and then supplied to the drying unit and used as dry hot air, thereby solving the problem that the pyrolysis oil and gas are condensed in the pyrolysis process of the prior art, which blocks the pipeline and burner, and the pyrolysis oil and gas are washed with water before being burned or other chemicals to produce a large amount of oil-containing wastewater, which is difficult to treat. The solid material containing pyrolysis carbon obtained in the cylinder of the pyrolysis unit can be separated by screening to obtain pyrolysis carbon, which can be used as a soil conditioner, etc., to improve economic benefits. Therefore, the use of this system not only effectively solves the problem that the pyrolysis oil and gas in the pyrolysis stage in the existing solid waste treatment process is difficult to extract due to coking of the pipeline or washing with water to produce oil-containing wastewater, but also realizes the resource utilization of organic solid waste and reduces costs.

[0013] In addition, the system for processing solid waste according to the above embodiment of the present invention may also have the following additional technical features:

[0014] In some embodiments of the present invention, the pyrolysis oil and gas pipeline extends along the length direction of the inner cylinder, and one end of the pyrolysis oil and gas pipeline is close to the front end of the inner cylinder, and the heat exchange flue gas outlet is arranged close to the front end of the inner cylinder. In this way, the residence time of the pyrolysis oil and gas in the combustion space after combustion and secondary air distribution can be extended, thereby improving the heat exchange efficiency.

[0015] In some embodiments of the present invention, the pyrolysis unit comprises a plurality of pyrolysis oil and gas pipelines, which are arranged at intervals along the circumferential direction of the outer peripheral wall of the inner cylinder, and the other ends of the pyrolysis oil and gas pipelines extend at different positions. Thus, the pyrolysis space in the inner cylinder can be heated evenly, thereby improving its pyrolysis efficiency.

[0016] In some embodiments of the present invention, a plurality of openings are provided on the other end of the pyrolysis oil and gas pipeline, thereby achieving full combustion of the pyrolysis oil and gas.

[0017] In some embodiments of the present invention, a baffle is provided in the combustion space, thereby improving the heat exchange efficiency of the combustion flue gas.

[0018] In some embodiments of the present invention, the above system further includes: a cyclone separator, the cyclone separator having a dry cold air inlet, a separated cold air outlet and a particle outlet, the dry cold air inlet is connected to the dry cold air outlet, and the separated cold air outlet is connected to the secondary air inlet.

[0019] In some embodiments of the present invention, the system further comprises: an exhaust gas purification unit having an exhaust gas inlet and a qualified exhaust gas outlet, wherein the exhaust gas inlet is connected to the post-separation cold air outlet.

[0020] In another aspect of the present invention, the present invention proposes a method for treating solid waste using the above system. According to an embodiment of the present invention, the method comprises:

[0021] (1) supplying solid waste to the pretreatment unit for pretreatment to obtain inorganic materials and organic materials;

[0022] (2) supplying the organic material to the drying unit to exchange heat with the dry hot air, so as to obtain dry material and dry cold air;

[0023] (3) The dried material is supplied to the inner cylinder of the pyrolysis unit through a feed screw for pyrolysis reaction, and the obtained pyrolysis oil and gas is supplied to the combustion space through the pyrolysis oil and gas pipeline to heat the inner cylinder after combustion with the primary air and mixing with the secondary air, thereby obtaining solid material and heat exchange flue gas, and the heat exchange flue gas is mixed with a part of the dry cold air and returned to step (2) for use as the dry hot air;

[0024] (4) The solid material is supplied to the screening device through a screw discharger provided with a cooling jacket for screening treatment to obtain pyrolytic carbon and solid waste.

[0025] The method for treating solid waste according to an embodiment of the present invention is to supply the solid waste to a pretreatment unit to remove large pieces of metal and other materials that cause the screw conveyor to be entangled / stuck, and then the obtained organic material is dried by a drying unit and sent to the inner cylinder of a pyrolysis unit for pyrolysis. As the inner cylinder rotates, the dry material therein is tumbled, so that the heating surface of the material is uniform, and at the same time, the spiral blades on the inner wall of the inner cylinder continuously push the material in the inner cylinder forward, and an outer cylinder is sleeved on the inner cylinder, and a pyrolysis oil and gas pipeline is arranged in a combustion space formed between the inner cylinder and the outer cylinder, one end of the pyrolysis oil and gas pipeline is connected to the pyrolysis space in the inner cylinder, and the other end extends in the combustion space, and a primary air inlet and a secondary air inlet are arranged in the outer cylinder near the other end of the pyrolysis oil and gas pipeline. The air inlet, that is, the pyrolysis oil and gas generated by the pyrolysis of the cylinder in the pyrolysis unit is introduced into the combustion space through the pyrolysis oil and gas pipeline to be mixed with the primary air for combustion. The combustion flue gas generated by the combustion is matched with the secondary air to provide a heat source for the pyrolysis reaction in the inner cylinder. The heat exchange flue gas obtained after heat exchange is matched with a part of the dry cold air and then supplied to the drying unit and used as dry hot air, thereby solving the problem that the pyrolysis oil and gas are condensed in the pyrolysis process of the prior art, which blocks the pipeline and burner, and the pyrolysis oil and gas are washed with water before burning or making other chemicals to produce a large amount of oil-containing wastewater, which is difficult to treat. The solid material containing pyrolytic carbon obtained in the cylinder of the pyrolysis unit can be separated by screening to obtain pyrolytic carbon, which can be used as a soil conditioner, etc., to improve economic benefits. Therefore, the use of this method not only effectively solves the problem that the pyrolysis oil and gas in the pyrolysis stage in the existing solid waste treatment process is difficult to extract due to pipeline coking or water washing, but also realizes the resource utilization of organic solid waste and reduces costs.

[0026] In addition, the method for treating solid waste according to the above embodiment of the present invention may also have the following additional technical features:

[0027] In some embodiments of the present invention, the above method further includes: (5) supplying another part of the dry cold air obtained in step (2) to a cyclone dust collector for separation treatment to obtain separated cold air and particles, and returning a part of the separated cold air to step (3) for use as the secondary air.

[0028] In some embodiments of the present invention, the above method further comprises: (6) supplying another part of the separated cold air to an exhaust gas purification unit for purification treatment so as to obtain exhaust gas that meets the standards.

[0029] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0031] Figure 1 is a schematic diagram of the structure of a system for processing solid waste according to an embodiment of the present invention;

[0032] Figure 2 is a schematic diagram of the longitudinal cross-section structure of a pyrolysis unit in a system for treating solid waste according to an embodiment of the present invention;

[0033] Figure 3 is a schematic diagram of the structure of a system for processing solid waste according to yet another embodiment of the present invention;

[0034] Figure 4 is a schematic flow chart of a method for treating solid waste according to an embodiment of the present invention;

[0035] Figure 5 The figure is a flow chart of a method for treating solid waste according to another embodiment of the present invention. DETAILED DESCRIPTION

[0036] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0037] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0038] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0040] In one aspect of the present invention, the present invention provides a system for treating solid waste. Figure 1-3 The system includes: a pretreatment unit 100, a drying unit 200, a pyrolysis unit 300 and a screening device 400.

[0041] According to an embodiment of the present invention, referring to Figure 1 The pretreatment unit 100 has a solid waste inlet 101, an inorganic material outlet 102 and an organic material outlet 103, and is suitable for pretreatment of solid waste to separate inorganic materials and organic materials. Specifically, solid waste includes sludge, garbage screen material, waste tires, waste plastics, agricultural and forestry waste, biogas residue and other solid wastes rich in organic matter, and the main purpose of the pretreatment unit is to crush or shape the material according to the properties of the material, and remove large pieces of metal and other inorganic materials that can cause the screw conveyor to entangle / jam; at the same time, as the garbage classification proceeds, high calorific value materials and low calorific value materials can be reasonably mixed so that the calorific value of the material itself is balanced with the energy required by the system (calculated based on the actual material calorific value and the system).

[0042] According to an embodiment of the present invention, referring to Figure 1The drying unit 200 has an organic material inlet 201, a drying hot air inlet 202, a drying material outlet 203 and a drying cold air outlet 204. The organic material inlet 201 is connected to the organic material outlet 103 and is suitable for exchanging heat between the organic material obtained above and the drying hot air to obtain the drying material and the drying cold air. Specifically, the organic material and the drying hot air can be indirectly or directly contacted for heat exchange, and the temperature in the drying unit is maintained at 200-250°C, the organic material stays in the drying unit for 40-90 minutes, and the moisture content of the obtained drying material is not higher than 20wt%.

[0043] According to an embodiment of the present invention, referring to Figure 1 and 2 The pyrolysis unit 300 includes an inner cylinder 31 and an outer cylinder 32 .

[0044] According to a specific embodiment of the present invention, referring to Figure 2 The inner cylinder 31 is rotatable in the horizontal direction, a pyrolysis space 33 is formed in the inner cylinder 31, and a spiral blade 311 is provided on the inner wall of the inner cylinder 31. As the inner cylinder 31 rotates, the dry material rolls in the inner cylinder 31, and the spiral blade 311 pushes the dry material entering the pyrolysis space 33 forward, and a dry material inlet 301 is provided at the front end of the inner cylinder 31, and the dry material inlet 301 is connected to the dry material outlet 203 through a feeding screw (not shown), and a solid material outlet 302 is provided at the rear end of the inner cylinder 31.

[0045] According to another specific embodiment of the present invention, Figure 1 and 2The outer cylinder 32 is sleeved on the inner cylinder 31, and a combustion space 34 is formed between the inner cylinder 31 and the outer cylinder 32. The combustion space 34 is provided with a pyrolysis oil and gas pipeline 35. One end 351 of the pyrolysis oil and gas pipeline 35 is connected to the pyrolysis space 33, and the other end 352 of the pyrolysis oil and gas pipeline 35 extends in the combustion space 34, that is, the pyrolysis oil and gas generated in the pyrolysis space 33 is directly introduced into the combustion space 34 through the pyrolysis oil and gas pipeline 35, and a primary air inlet 303 and a secondary air inlet 304 are provided on the outer cylinder 32 near the other end 352 of the pyrolysis oil and gas pipeline 35. The secondary air inlet 304 is staggered with the other end 352 of the pyrolysis oil and gas pipeline 35, so as to avoid the secondary air blown in to blow out the flame of the pyrolysis oil and gas, that is, to introduce The pyrolysis oil and gas in the combustion space 34 are mixed with the primary air and burned, and the obtained combustion flue gas is then mixed with the secondary air to heat the inner cylinder 31, providing a heat source for the pyrolysis of the dry material in the pyrolysis space 33 in the inner cylinder 31, and a heat exchange flue gas outlet 305 is provided on the outer cylinder 32 at the other end 352 away from the pyrolysis oil and gas pipeline 35, that is, the residence time of the combustion flue gas in the combustion space 34 is extended to improve the heat exchange efficiency, and the heat exchange flue gas obtained after heat exchange is discharged from the heat exchange flue gas outlet 305, and the heat exchange flue gas outlet 305 and the dry cold air outlet 204 are connected to the dry hot air inlet 202, that is, the heat exchange flue gas after heat exchange is mixed with a part of the dry cold air obtained by the above-mentioned drying unit 200 and supplied to the drying unit 200 for use as dry hot air. The inventors have discovered that the present application improves the existing pyrolysis unit so that the pyrolysis oil and gas generated by the pyrolysis of the inner cylinder is directly supplied to the combustion space through a pipeline for combustion to provide heat for the inner cylinder. This not only reduces the pyrolysis unit's dependence on external energy, but also solves the problems of the prior art pyrolysis process in which tar condenses when the pyrolysis oil and gas is discharged, thereby clogging the pipeline and the burner, and the pyrolysis oil and gas is washed with water before combustion or production of other chemicals to produce a large amount of oil-containing wastewater, which is difficult to treat.

[0046] Further, refer to Figure 2The pyrolysis oil and gas pipeline 35 extends along the length direction of the inner cylinder 31, and one end 351 of the pyrolysis oil and gas pipeline 35 is close to the front end of the inner cylinder 31, and the heat exchange flue gas outlet 305 is arranged close to the front end of the inner cylinder 31, that is, the pyrolysis oil and gas generated in the pyrolysis space 33 is discharged from a position close to the front end of the inner cylinder 31 and then supplied to the combustion space 34 through the pyrolysis oil and gas pipeline 35. The heat exchange flue gas outlet 305 is arranged close to the front end of the inner cylinder 31, which can extend the residence time of the combustion flue gas and the secondary air in the combustion space after the air is matched, thereby improving the heat exchange efficiency. Preferably, a plurality of pyrolysis oil and gas pipelines 35 may be arranged in the combustion space 33, and the plurality of pyrolysis oil and gas pipelines 35 may be arranged at intervals along the circumferential direction of the outer wall of the inner cylinder 31, and the other ends 352 of the pyrolysis oil and gas pipelines 35 may extend at different positions, wherein the number of pyrolysis oil and gas pipelines 35 may correspond one-to-one to the number of primary air inlets 303, or one primary air inlet 303 may be provided for several pyrolysis oil and gas pipelines 35, and similarly, the number of secondary air inlets 304 may correspond one-to-one to the number of pyrolysis oil and gas pipelines 35, or one secondary air inlet 304 may be provided for several pyrolysis oil and gas pipelines 35. Those skilled in the art may make a choice according to actual needs, and preferably, the extension positions of the other ends 352 of the pyrolysis oil and gas pipelines 35 may increase successively along the circumferential direction of the outer wall of the inner cylinder 31, thereby ensuring uniform heating of the inner cylinder and improving the heat exchange efficiency in the inner cylinder. Furthermore, in order to fully burn the pyrolysis oil and gas supplied to the pyrolysis oil and gas pipeline 35, a plurality of openings (not shown) are provided on the other end 352 of the pyrolysis oil and gas pipeline 35, that is, the pyrolysis oil and gas supplied through the pyrolysis oil and gas pipeline 35 is mixed with the primary air and burned after being ejected through the plurality of openings. At the same time, in order to further improve the heat exchange efficiency between the combustion flue gas and the secondary air after being matched with the inner cylinder 31, a baffle (not shown) is preferably provided in the combustion space 34, which can increase the residence time of the combustion flue gas and the secondary air after being matched with the combustion space, and at the same time, can realize the turbulence effect of the combustion flue gas and the secondary air after being matched with the combustion space to achieve the purpose of turbulence and improve the heat exchange efficiency. It should be noted that technical personnel in this field can select the number of pyrolysis oil and gas pipelines 35 according to actual needs, as long as the inner cylinder 31 can be heated evenly. At the same time, the present application has no special restrictions on the size of multiple openings on the other end 352 of the pyrolysis oil and gas pipeline 35, as long as the pyrolysis oil and gas supplied through the pyrolysis oil and gas pipeline 35 and the primary air can be fully burned. In addition, the present application has no strict restrictions on the specific type of baffle, as long as the above-mentioned increase in the residence time of the combustion flue gas and the secondary air after the air distribution in the combustion space can be achieved, and the turbulence effect of the combustion flue gas and the secondary air after the air distribution in the combustion space can be achieved.

[0047] According to an embodiment of the present invention, referring to Figure 1The screening device 400 has a solid material inlet 401, a pyrolytic carbon outlet 402 and a solid waste outlet 403. The solid material inlet 401 is connected to the solid material outlet 302 through a screw discharger (not shown) provided with a cooling jacket, and is suitable for screening the solid material containing pyrolytic carbon obtained by the pyrolysis unit 300, so as to separate pyrolytic carbon and solid waste containing glass, bricks and metals, etc. The pyrolytic carbon obtained after screening the solid material can be used as a soil conditioner. It should be noted that those skilled in the art can select the specific type of the screening device according to actual needs, as long as the separation of pyrolytic carbon can be achieved.

[0048] The system for treating solid waste according to an embodiment of the present invention supplies solid waste to a pretreatment unit to remove large pieces of metal and other materials that cause the screw conveyor to be entangled / stuck, and then dries the obtained organic material in a drying unit and sends it to the inner cylinder of a pyrolysis unit for pyrolysis. As the inner cylinder rotates, the dry material therein is tumbled, so that the heating surface of the material is uniform, and at the same time, the spiral blades on the inner wall of the inner cylinder continuously push the material in the inner cylinder forward, and an outer cylinder is sleeved on the inner cylinder, and a pyrolysis oil and gas pipeline is arranged in a combustion space formed between the inner cylinder and the outer cylinder. One end of the pyrolysis oil and gas pipeline is connected to the pyrolysis space in the inner cylinder, and the other end extends in the combustion space, and a primary air inlet and a secondary air inlet are provided in the outer cylinder near the other end of the pyrolysis oil and gas pipeline. The air inlet, that is, the pyrolysis oil and gas generated by the pyrolysis of the cylinder in the pyrolysis unit is introduced into the combustion space through the pyrolysis oil and gas pipeline to be mixed with the primary air for combustion. The combustion flue gas generated by the combustion is matched with the secondary air to provide a heat source for the pyrolysis reaction in the inner cylinder. The heat exchange flue gas obtained after heat exchange is matched with a part of the dry cold air and then supplied to the drying unit and used as dry hot air, thereby solving the problem that the pyrolysis oil and gas are condensed in the pyrolysis process of the prior art, which blocks the pipeline and burner, and the pyrolysis oil and gas are washed with water before being burned or other chemicals to produce a large amount of oil-containing wastewater, which is difficult to treat. The solid material containing pyrolysis carbon obtained in the cylinder of the pyrolysis unit can be separated by screening to obtain pyrolysis carbon, which can be used as a soil conditioner, etc., to improve economic benefits. Therefore, the use of this system not only effectively solves the problem that the pyrolysis oil and gas in the pyrolysis stage in the existing solid waste treatment process is difficult to extract due to coking of the pipeline or washing with water to produce oil-containing wastewater, but also realizes the resource utilization of organic solid waste and reduces costs.

[0049] For further reference, Figure 3 The system further includes: a cyclone separator 500 and an exhaust gas purification unit 600.

[0050] According to an embodiment of the present invention, the cyclone separator 500 has a dry cold air inlet 501, a separated cold air outlet 502 and a particle outlet 503, the dry cold air inlet 501 is connected to the dry cold air outlet 204, the separated cold air outlet 502 is connected to the secondary air inlet 304, and is suitable for cyclone dust removal of another part of the dry cold air obtained by the drying unit 200, separating particles and separated cold air, and supplying a part of the separated cold air to the pyrolysis unit 300 for use as secondary air. Preferably, the cyclone separator is a cyclone separator made of high temperature resistant material.

[0051] According to an embodiment of the present invention, the tail gas purification unit 600 has a tail gas inlet 601 and a standard tail gas outlet 602, the tail gas inlet 601 is connected to the separated cold air outlet 502, and is suitable for purifying and removing dust from another part of the separated cold air obtained above, so as to achieve standard tail gas emission. Specifically, the tail gas purification unit includes a cyclone dust collector, a water washing tower, an alkali washing tower, a deodorizing device, an activated carbon adsorption device, etc., and those skilled in the art can select according to actual needs, as long as the tail gas can be discharged in a standard manner.

[0052] As described above, the system for processing solid waste according to the embodiment of the present invention has at least one of the following beneficial effects:

[0053] (1) The present application arranges the pyrolysis oil and gas pipeline in the inner ring system of the combustion space formed by the inner cylinder and the outer cylinder of the pyrolysis unit, so that the pyrolysis oil and gas generated in the inner cylinder are directly burned in the combustion space, thereby avoiding coking and blockage of the pyrolysis oil and gas transmission pipeline;

[0054] (2 The present application sets the pyrolysis oil and gas pipelines in the combustion space to different lengths so that the pyrolysis oil and gas are evenly released along the rotation direction of the furnace body, and is equipped with a separate primary air and secondary air introduction system to ensure uniform temperature of the entire furnace body, reduce deformation of the furnace body or tearing of welds caused by uneven temperature, and extend the service life of the pyrolysis furnace;

[0055] (3) The pyrolysis oil and gas generated by pyrolysis in the present application is directly burned in the combustion space outside the inner cylinder. The heat after combustion directly heats the inner cylinder, and the heat utilization rate is high;

[0056] (4) The inner cylinder of the pyrolysis unit of the present application rotates continuously, and the dried material rotates along with the spiral blades arranged on the inner wall of the inner cylinder and the heating surface is continuously replaced, so that the heating is uniform and the pyrolysis effect is good.

[0057] In another aspect of the present invention, the present invention provides a method for treating solid waste using the above system. Figure 4 and 5 , the method comprising:

[0058] S100: Supplying solid waste to a pretreatment unit for pretreatment

[0059] In this step, the solid waste is supplied to the pretreatment unit for pretreatment to obtain inorganic materials and organic materials. Specifically, the solid waste includes sludge, garbage screen material, waste tires, waste plastics, agricultural and forestry waste, biogas residue and other solid wastes rich in organic matter, and the main purpose of the pretreatment unit is to crush or shape the material according to the nature of the material, and remove the inorganic materials such as large pieces of metal that can cause the screw conveyor to entangle / jam; at the same time, as the garbage classification proceeds, the high calorific value material and the low calorific value material can be reasonably mixed so that the calorific value of the material itself is balanced with the energy required by the system (calculated according to the actual material calorific value and the system).

[0060] S200: Supply organic materials to the drying unit for heat exchange with dry hot air

[0061] In this step, the organic material obtained above is supplied to the drying unit for heat exchange with the drying hot air, so as to obtain the dried material and the drying cold air. Specifically, the organic material and the drying hot air can be indirectly or directly contacted for heat exchange, and the temperature in the drying unit is maintained at 200-250° C., the residence time of the organic material in the drying unit is 40-90 minutes, and the moisture content of the obtained dried material is not higher than 20wt%.

[0062] S300: The dry material is supplied to the inner cylinder of the pyrolysis unit through the feeding screw for pyrolysis reaction, and the obtained pyrolysis oil and gas are supplied to the combustion space through the pyrolysis oil and gas pipeline, and after combustion with the primary air and air matching with the secondary air, the inner cylinder is heated, and the heat exchange flue gas is matched with a part of the dry cold air and then returns to step S200.

[0063] In this step, the dry material obtained above is supplied to the inner cylinder of the pyrolysis unit through the feed screw for pyrolysis reaction, and the obtained pyrolysis oil and gas are supplied to the combustion space through the pyrolysis oil and gas pipeline, and then burned with the primary air and matched with the secondary air to provide heat for the inner cylinder, so that the dry material undergoes pyrolysis reaction in the inner cylinder to obtain solid material, and the combustion flue gas in the combustion space is matched with the secondary air and then heat-exchanged with the inner cylinder to obtain heat-exchanged flue gas, and the heat-exchanged flue gas is matched with a part of the dry cold air and returned to step S200 for use as dry hot air. The inventor found that the present application improves the existing pyrolysis unit so that the pyrolysis oil and gas generated by the pyrolysis of the inner cylinder are directly supplied to the combustion space through the pipeline for combustion and matched with the secondary air to provide heat for the inner cylinder, which not only reduces the dependence of the pyrolysis unit on external energy, but also solves the problem that the pyrolysis oil and gas are extracted in the pyrolysis process of the prior art, resulting in tar condensation and blocking of the pipeline and burner, and the problem that the pyrolysis oil and gas are washed with water and then burned or other chemicals are produced to generate a large amount of oil-containing wastewater, which is difficult to treat.

[0064] S400: The solid material is fed to the screening device through a screw discharger with a cooling jacket for screening.

[0065] In this step, the solid material obtained by the above pyrolysis process is supplied to a screening device through a screw discharger provided with a cooling jacket for screening treatment, so as to obtain pyrolytic carbon and solid waste containing glass, bricks and metals, etc. The pyrolytic carbon obtained after screening the solid material can be used as a soil conditioner. It should be noted that those skilled in the art can select the specific type of the screening device according to actual needs, as long as the separation of pyrolytic carbon can be achieved.

[0066] The method for treating solid waste according to an embodiment of the present invention is to supply the solid waste to a pretreatment unit to remove large pieces of metal and other materials that cause the screw conveyor to be entangled / stuck, and then the obtained organic material is dried by a drying unit and sent to the inner cylinder of a pyrolysis unit for pyrolysis. As the inner cylinder rotates, the dry material therein is tumbled, so that the heating surface of the material is uniform, and at the same time, the spiral blades on the inner wall of the inner cylinder continuously push the material in the inner cylinder forward, and an outer cylinder is sleeved on the inner cylinder, and a pyrolysis oil and gas pipeline is arranged in a combustion space formed between the inner cylinder and the outer cylinder, one end of the pyrolysis oil and gas pipeline is connected to the pyrolysis space in the inner cylinder, and the other end extends in the combustion space, and a primary air inlet and a secondary air inlet are arranged in the outer cylinder near the other end of the pyrolysis oil and gas pipeline. The air inlet, that is, the pyrolysis oil and gas generated by the pyrolysis of the cylinder in the pyrolysis unit is introduced into the combustion space through the pyrolysis oil and gas pipeline to be mixed with the primary air for combustion. The combustion flue gas generated by the combustion is matched with the secondary air to provide a heat source for the pyrolysis reaction in the inner cylinder. The heat exchange flue gas obtained after heat exchange is matched with a part of the dry cold air and then supplied to the drying unit and used as dry hot air, thereby solving the problem that the pyrolysis oil and gas are condensed in the pyrolysis process of the prior art, which blocks the pipeline and burner, and the pyrolysis oil and gas are washed with water before burning or making other chemicals to produce a large amount of oil-containing wastewater, which is difficult to treat. The solid material containing pyrolytic carbon obtained in the cylinder of the pyrolysis unit can be separated by screening to obtain pyrolytic carbon, which can be used as a soil conditioner, etc., to improve economic benefits. Therefore, the use of this method not only effectively solves the problem that the pyrolysis oil and gas in the pyrolysis stage in the existing solid waste treatment process is difficult to extract due to pipeline coking or water washing, but also realizes the resource utilization of organic solid waste and reduces costs.

[0067] For further reference, Figure 5 , the above method further comprises:

[0068] S500: another part of the dry cold air obtained in step S200 is supplied to the cyclone dust collector for separation, and a part of the separated cold air is returned to step S300 for use as secondary air

[0069] In this step, another part of the dry cold air obtained in step S200 is supplied to the cyclone dust collector for separation treatment to obtain separated cold air and particles, and a part of the separated cold air is returned to step S300 for use as secondary air. Preferably, the cyclone separator is a cyclone separator made of high temperature resistant material.

[0070] S600: The other part of the separated cold air is supplied to the exhaust gas purification unit for purification

[0071] In this step, another part of the separated cold air is supplied to the tail gas purification unit for purification treatment to obtain tail gas that meets the standards. Specifically, the tail gas purification unit includes a cyclone dust collector, a water scrubber, an alkali scrubber, a deodorizing device, and an activated carbon adsorption device, etc. Those skilled in the art can select them according to actual needs, as long as the tail gas can be discharged in compliance with the standards.

[0072] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0073] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A system for treating solid waste, characterized in that: include: A pretreatment unit, wherein the pretreatment unit has a solid waste inlet, an inorganic material outlet, and an organic material outlet; A drying unit, wherein the drying unit has an organic material inlet, a dry hot air inlet, a dry material outlet and a dry cold air outlet, and the organic material inlet is connected to the organic material outlet; A pyrolysis unit, the pyrolysis unit comprising: An inner cylinder, wherein the inner cylinder is rotatably arranged, a pyrolysis space is formed in the inner cylinder, a spiral blade is arranged on the inner wall of the inner cylinder, a dry material inlet is arranged at the front end of the inner cylinder, the dry material inlet is connected to the dry material outlet via a feed spiral, and a solid material outlet is arranged at the rear end of the inner cylinder; An outer cylinder, wherein the outer cylinder is sleeved on the inner cylinder, and a combustion space is formed between the inner cylinder and the outer cylinder, wherein a pyrolysis oil and gas pipeline is provided in the combustion space, wherein one end of the pyrolysis oil and gas pipeline is communicated with the pyrolysis space, and the other end of the pyrolysis oil and gas pipeline extends in the combustion space, and a primary air inlet and a secondary air inlet are provided on the outer cylinder near the other end of the pyrolysis oil and gas pipeline, and the secondary air inlet is staggered with the other end of the pyrolysis oil and gas pipeline, and a heat exchange flue gas outlet is provided on the outer cylinder away from the other end of the pyrolysis oil and gas pipeline, and the heat exchange flue gas outlet and the dry cold air outlet are connected to the dry hot air inlet; A screening device, wherein the screening device has a solid material inlet, a pyrolytic carbon outlet and a solid waste outlet, and the solid material inlet and the solid material outlet are connected via a screw discharger provided with a cooling jacket; The pyrolysis oil and gas pipeline extends along the length direction of the inner cylinder, and one end of the pyrolysis oil and gas pipeline is close to the front end of the inner cylinder, and the heat exchange flue gas outlet is arranged close to the front end of the inner cylinder; It comprises a plurality of pyrolysis oil and gas pipelines, which are arranged at intervals along the circumferential direction of the outer peripheral wall of the inner cylinder, and the other ends of the pyrolysis oil and gas pipelines extend at different positions; The other end of the pyrolysis oil and gas pipeline is provided with a plurality of openings.

2. The system according to claim 1, characterized in that A baffle is arranged in the combustion space.

3. The system according to claim 1, characterized in that Further including: A cyclone separator, wherein the cyclone separator has a dry cold air inlet, a separated cold air outlet and a particle outlet, wherein the dry cold air inlet is connected to the dry cold air outlet, and the separated cold air outlet is connected to the secondary air inlet.

4. The system according to claim 3, characterized in that Further including: The tail gas purification unit comprises a tail gas inlet and a standard tail gas outlet, wherein the tail gas inlet is connected to the post-separation cold air outlet.

5. A method for treating solid waste using the system according to any one of claims 1 to 4, characterized in that: include: (1) supplying solid waste to the pretreatment unit for pretreatment to obtain inorganic materials and organic materials; (2) supplying the organic material to the drying unit to exchange heat with the dry hot air, so as to obtain dry material and dry cold air; (3) The dried material is supplied to the inner cylinder of the pyrolysis unit through the feed screw for pyrolysis reaction, and the obtained pyrolysis oil and gas is supplied to the combustion space through the pyrolysis oil and gas pipeline to heat the inner cylinder after combustion with the primary air and mixing with the secondary air, thereby obtaining solid material and heat exchange flue gas, and the heat exchange flue gas is mixed with a part of the drying cold air and returned to step (2) for use as the drying hot air; (4) The solid material is supplied to the screening device through a screw discharger provided with a cooling jacket for screening treatment, so as to obtain pyrolytic carbon and solid waste.

6. The method according to claim 5, characterized in that Further including: (5) Another part of the dry cold air obtained in step (2) is supplied to a cyclone dust collector for separation to obtain separated cold air and particles, and a part of the separated cold air is returned to step (3) for use as the secondary air.

7. The method according to claim 6, characterized in that Further including: (6) Another portion of the separated cold air is supplied to an exhaust gas purification unit for purification so as to obtain exhaust gas that meets the standards.

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