A garbage hydrogen production pretreatment system and pretreatment process

Abstract

The waste hydrogen production pretreatment system and pretreatment process of the present invention include a silo, which comprises, from bottom to top, a sedimentation layer, an air separation layer, and a suspension layer. A garbage inlet is connected to the silo wall on the side of the silo corresponding to the air separation layer, and the garbage inlet is connected to a pneumatic conveying mechanism, which delivers the garbage into the air separation layer within the silo. A first fan is connected to the silo wall on the side of the silo corresponding to the sedimentation layer, which delivers fluidizing air into the silo. A slit channel is provided on one side of the bottom of the silo. A horizontal extension channel connected to the silo inner cavity is provided on the side of the top of the silo opposite the garbage inlet. A second fan is connected to the end of the horizontal extension channel, and a filter is provided in the extension channel. A vertically arranged collecting pipe is connected to the portion of the extension channel between the filter and the silo inner cavity. The process of the present invention can improve the drying rate, ensure the uniformity of the drying effect, and reduce mechanical equipment failures. Compared with existing processes, it can improve the drying time by about 30%.

Description

Technical Field

[0001] The present invention belongs to the technical field of domestic waste treatment, and in particular relates to a waste hydrogen production pretreatment system and a pretreatment process. Background Art

[0002] Currently, incineration is the primary method for disposing of domestic waste (accounting for over 60%). While it can reduce waste volume, high-temperature combustion results in significant waste heat loss, and its energy efficiency is generally below 25%, resulting in energy waste. This method of converting the chemical energy of domestic waste into electricity is essentially a "low-value utilization" model.

[0003] Hydrogen energy has attracted considerable attention as a green energy source. Municipal waste contains 40%-60% organic matter (plastics, biomass, etc.), which can be specifically converted into green hydrogen through thermochemical conversion, thus achieving the dual benefits of waste resource utilization and clean energy production. However, the complex composition and high moisture content of municipal waste necessitate pretreatment before further gasification and hydrogen production.

[0004] Municipal solid waste is rich in organic raw materials (such as biomass and rubber), which can be converted into high-value products such as hydrogen, methanol, and sustainable aviation fuel through thermochemical conversion. Municipal solid waste has a high moisture content (50%-60%), complex composition, and widely varying physical properties. Before entering the gasifier to produce syngas, the solid waste must be pretreated to achieve dryness and uniform properties. The existing pretreatment process for municipal solid waste gasification and hydrogen production generally involves crushing, drying, baking, screening, and grinding. Raw municipal solid waste with a moisture content of 50%-60% is fed into a crusher for crushing, then dried in a drying unit, typically a rotary kiln or drum. The dried waste enters a low-temperature pyrolysis carbonization unit for baking and charcoal production. It is then sorted to remove impurities such as sand, stone, and glass. The pyrolytic charcoal is then ground and fed into the gasifier for gasification.

[0005] The current pretreatment process for hydrogen production from domestic waste has the following problems:

[0006] (1) Most existing processes use rotary kilns or drums to dry garbage, which has the disadvantages of poor drying effect and large equipment size.

[0007] Municipal solid waste has a high moisture content, necessitating drying during hydrogen production pretreatment. Current drying equipment primarily utilizes rotary kilns or drums for direct and indirect heating. Drying wet solid waste in rotary kilns and drums relies primarily on heat conduction, but the low thermal conductivity of municipal solid waste results in poor heat transfer and prolonged drying times. Furthermore, large temperature gradients within the drying reactor lead to significant moisture fluctuations in the outlet material. High moisture content in the inlet material can easily lead to feed blockage.

[0008] (2) The existing waste hydrogen production pretreatment process is relatively long

[0009] Existing pretreatment processes for hydrogen production from municipal solid waste mostly utilize a series connection of equipment, such as a crusher + dryer + baking equipment + sorting equipment + grinding. Each process in this process relies on independent equipment, resulting in a lengthy pretreatment process.

[0010] (3) The existing waste hydrogen production pretreatment process is unstable and has many mechanical equipment failures.

[0011] Existing pretreatment processes for hydrogen production from municipal solid waste mostly use mechanical equipment for sorting and drying. This equipment often involves moving parts, making it prone to mechanical failures during operation and resulting in unstable operations. Furthermore, this large number of moving parts results in high energy consumption. Summary of the Invention

[0012] To address the above technical issues, the present invention proposes a novel pretreatment process for producing hydrogen from household waste gasification. Compared to existing processes, this process improves drying rates, ensures uniform drying results, and reduces mechanical equipment failures. Furthermore, it reduces the processing time by approximately 30%.

[0013] In order to achieve the above technical objectives, the present invention adopts the following technical means:

[0014] A garbage hydrogen production pretreatment system, comprising:

[0015] The silo body comprises, from bottom to top, a sedimentation layer, an air separation layer, and a suspension layer. A garbage inlet is connected to a silo wall on one side of the silo body corresponding to the air separation layer. The garbage inlet is connected to a pneumatic conveying mechanism. The pneumatic conveying mechanism is provided with a first garbage crushing unit. The garbage crushed by the first garbage crushing unit can be conveyed into the air separation layer in the silo body along the tangential direction of the silo wall through the pneumatic conveying mechanism.

[0016] A first fan is connected to a silo wall on one side of the silo corresponding to the sediment layer, and is configured to deliver fluidizing air with a temperature range of 80-250°C into the silo. An air distribution plate is provided inside the silo above the air outlet of the first fan. One end of the air distribution plate is connected to an inner wall of one side of the silo, and the other end is arranged downwardly and connected to one end of a baffle. The other end of the baffle is connected to the silo bottom. A narrow slit channel is formed between the baffle and the inner wall on the other side of the silo for the heavy waste to be discharged from the silo.

[0017] A horizontal extension channel is provided on the side of the top of the bin body opposite to the garbage inlet and communicates with the inner cavity of the bin body. The end of the horizontal extension channel is connected to a second fan for inducing air, and a filter is provided in the horizontal extension channel.

[0018] A vertically arranged material collecting pipe is connected to the lower side wall of the horizontally extending channel between the filter screen and the inner cavity of the bin body. The upper end of the material collecting pipe is connected to the interior of the horizontally extending channel, and the lower end of the material collecting pipe is connected to the extrusion conveying mechanism, the baking equipment and the grinding mill in sequence;

[0019] A first star-shaped discharge valve is installed between the lower end of the collecting pipe and the feed port of the extrusion conveying mechanism.

[0020] Beneficial effects: good garbage drying effect and high efficiency:

[0021] In the drying and air separation equipment, the garbage is in direct contact with the hot fluidized air, which has a high heat transfer efficiency. By controlling the fluidization speed, the garbage is kept in a turbulent state in the fluidization zone, and the mutual collision and friction between the garbage particles can further enhance the heat transfer efficiency.

[0022] Integrated design of drying and air separation, with shorter process flow:

[0023] Utilizing the density differences between light and heavy waste, the separation of light and heavy components of primary waste is achieved within a single drying and air separation device. Heavy waste flows out of the reactor from the bottom, between the baffle and the reactor wall. Light waste dries in the fluidized bed. As water evaporates, its density decreases. Driven by airflow, it enters the suspended layer, passes through the filter screen, and enters the vertically arranged collection pipe.

[0024] Garbage is now screened partially instead of fully, reducing the pressure on sorting equipment:

[0025] The waste that emerges from the bottom of the dry air separation equipment is heavy waste, primarily consisting of large, non-fluidizable organic waste. In addition, denser materials like metal and stone are also concentrated in the heavy waste. Therefore, the dry air separation equipment has already performed a preliminary sorting of the waste. In the subsequent fine sorting process, only the heavy waste is sorted, thus separating inorganic components like metal and stone from the raw waste, significantly reducing the pressure on the sorting equipment.

[0026] Reduced mechanical equipment and increased process stability:

[0027] The warehouse can greatly reduce the number of mechanical sorting equipment in the existing process and greatly reduce the failure rate of mechanical equipment, thereby ensuring the stable operation of the project.

[0028] In an optional embodiment, the pneumatic conveying mechanism includes:

[0029] The first garbage crushing unit has its discharge port connected to the throat of the venturi tube through a first pipe. One end of the venturi tube is connected to the air outlet of the third fan used to send garbage into the air separation layer in the silo, and the other end is connected to the inner cavity of the silo along the tangential direction of the silo wall of a silo; a second star-shaped unloading valve is installed on the first pipe.

[0030] Beneficial effects: Using Venturi for pneumatic conveying can greatly improve the efficiency of garbage transportation. At the same time, pneumatic conveying can better seal the pipeline and prevent odor from overflowing.

[0031] In an optional embodiment, the extrusion conveying mechanism is a variable diameter screw conveyor, and the diameter of the variable diameter screw conveyor gradually decreases along the conveying direction.

[0032] Beneficial effect: The compression in the variable diameter spiral increases the density of domestic garbage, and the air inside the garbage is discharged during the compression process to ensure the oxygen-free atmosphere required for subsequent baking.

[0033] In an optional embodiment, the method further includes:

[0034] An optical sorting and screening machine, wherein the bottom of the slit channel is connected to the optical sorting and screening machine via a second pipe, and the optical sorting and screening machine is used to screen the heavy waste into organic waste and non-organic waste; a third star-shaped discharge valve is installed on the second pipe;

[0035] The second garbage crushing unit is used to crush the organic garbage screened by the optical screening machine again to further reduce the particle size of this part of the garbage; the organic garbage crushed by the second garbage crushing unit is transported to the first garbage crushing unit again through the third pipeline and enters the air separation layer inside the warehouse through the Venturi tube.

[0036] Beneficial effects: The heavy component garbage coming out of the reactor passes through the optical screening machine to separate the heavy organic garbage from sand, stone and metal substances. The heavy organic garbage is then transported to the crusher for fine crushing, and then added to the crusher for crushing to further reduce the particle size of this part of the garbage. After crushing, it is added to the drying and air separation equipment again.

[0037] In an optional embodiment, the connection end of the venturi tube and the chamber body has a downward slope of 1-3°.

[0038] Beneficial effect: The delivery pipe where the venturi tube is located has a slope of 1-3 degrees, which can prevent garbage from clogging the pipe.

[0039] In an optional embodiment, a rib plate is provided on the inner wall surface of the bin body located at the air separation layer.

[0040] Beneficial effect: By setting ribs on the wall, the flow field in the reactor is increased by turbulent kinetic energy, further strengthening the interphase heat exchange and improving the drying efficiency.

[0041] In an optional embodiment, the angle between the air distribution plate and the horizontal direction is 15-20°, and the angle between the baffle and the horizontal direction is 45-60°.

[0042] Beneficial Effect: Because the air distribution plate is set at a certain angle, greater than the repose angle of the domestic waste, the airflow loosens the heavier domestic waste and causes it to fall along the air distribution plate into the narrow gap between the baffle and the wall of the drying and air separation equipment. The air distribution plate is connected to the baffle, and there is a gap between the baffle and the reactor wall. The angle between the baffle and the horizontal direction is 45-60 degrees.

[0043] In an optional embodiment, a scraping brush that moves periodically is provided on the filter screen.

[0044] The present invention further discloses a pretreatment process based on the waste hydrogen production pretreatment system, wherein the raw waste is crushed by a first waste crushing unit on a pneumatic conveying mechanism, and the particle size of the crushed waste is between 20 and 30 mm; the crushed waste is pneumatically conveyed by the pneumatic conveying mechanism and enters the bin along a tangential nozzle, and the tangential injection into the equipment forms a vortex;

[0045] The first fan blows hot air of no less than 80℃ into the bottom of the silo. The hot air enters the silo under the action of the air distribution plate. By controlling the wind speed, the garbage is stratified in the silo. The garbage entering the silo by pneumatic conveying first enters the air separation layer. The heavier components will gradually settle in the sedimentation layer at the bottom of the silo due to the greater gravity.

[0046] An air distribution plate 8 is provided at the bottom of the drying fluidized bed. As the air distribution plate is arranged downwardly and is larger than the repose angle of the domestic waste, the heavier domestic waste will fall along the air distribution plate into the narrow channel between the baffle and the wall of the bin under the loosening effect of the air flow, and the heavy waste will be discharged from the bin;

[0047] Light garbage stays in the air separation layer for a period of time. In this area, heat exchange occurs between the garbage and the high-temperature fluidized air, thereby increasing the temperature and evaporating the water. At the same time, the collision between the garbage particles will enhance the drying effect. During the drying process, the moisture content of the garbage gradually decreases, and the gravity decreases, turning it into light garbage and entering the suspension layer. Thereafter, it enters the horizontal extension channel under the action of the induced draft fan, and is separated into gas and solid under the action of the filter screen. The low-temperature gas is discharged through the filter screen, and the solid garbage falls into the collection pipe under the action of gravity.

[0048] The moisture content of the garbage in the collecting pipe is 20%-25%. It enters the extrusion conveying mechanism for compression to increase the density of the garbage, and the air inside the garbage is discharged during the compression process to ensure the oxygen-free atmosphere required for subsequent baking. The compressed garbage is sent to the baking equipment for low-temperature baking. The baking temperature is between 150-250℃ and the residence time is 1-2h. Under low-temperature baking, the garbage will produce semi-coke, which is further added to the grinder for grinding. The particle size of the ground carbon powder is 200-300um, which is used as the raw material for entrained bed or fluidized bed gasification.

[0049] Furthermore, thermal oil is used as the heat transfer medium in the baking equipment. The heat transfer between the thermal oil and the garbage is indirect heat transfer. The temperature difference between the inlet and outlet of the thermal oil does not exceed 10°C. The energy required by the baking equipment comes from electricity or the combustion of pyrolysis gas generated by baking. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 This is a schematic structural diagram of the waste hydrogen production pretreatment system of the present invention;

[0051] Among them, 1 is the conveyor belt; 2 is the first garbage crushing unit; 3 is the second star-shaped unloading valve; 4 is the third fan; 5 is the Venturi tube; 6 is the bin body; 7 is the heavy garbage outlet; 8 is the air distribution plate; 9 is the baffle; 10 is the third star-shaped unloading valve; 11 is the optical screening machine; 12 is the second garbage crushing unit; 13 is the light garbage outlet; 14 is the filter screen; 17 is the second fan; 18 is the collecting pipe; 19 is the first star-shaped unloading valve; 20 is the variable diameter screw conveyor; 21 is the baking equipment; 22 is the long-term electric thermal oil furnace; 23 is the grinding mill; 24 is the first fan.

[0052] Figure 2 is a schematic cross-sectional view of the warehouse body;

[0053] Among them, 15 is the rib plate; 16 is the garbage entrance. DETAILED DESCRIPTION

[0054] The technical solution of the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can have a clearer understanding of the technical solution of the present invention.

[0055] Example 1: Figure 1 As shown, a waste hydrogen production pretreatment system includes:

[0056] The silo 6 comprises, from bottom to top, a sedimentation layer, an air separation layer, and a suspension layer. A garbage inlet 16 is connected to a silo wall on one side of the silo 6 corresponding to the air separation layer. The garbage inlet 16 is connected to a pneumatic conveying mechanism. The pneumatic conveying mechanism is provided with a first garbage crushing unit 2. The garbage crushed by the first garbage crushing unit 2 can be transported by the pneumatic conveying mechanism along the tangent direction of the silo wall of the silo 6 into the air separation layer within the silo 6.

[0057] A first fan 24 is connected to the silo wall on one side of the silo body 6 corresponding to the sediment layer, and is used to deliver high-temperature fluidizing air into the silo body. The temperature of the high-temperature fluidizing air ranges from 80°C to 250°C. An air distribution plate 8 is provided inside the silo body 6 above the air outlet of the first fan 24. One end of the air distribution plate 8 is connected to the inner wall of one side of the silo body 6, and the other end is arranged downwardly and connected to one end of a baffle 9. The other end of the baffle 9 is connected to the bottom of the silo. A narrow slit channel is formed between the baffle 9 and the inner wall on the other side of the silo body 6 for the heavy component waste to be discharged from the silo.

[0058] A horizontal extension channel is provided on the top of the bin body 6 on the side opposite to the garbage inlet 16 and connected to the inner cavity of the bin body 6. The end of the horizontal extension channel is connected to a second fan 17 for inducing air, and a filter 14 is provided in the extension channel.

[0059] A vertically arranged collecting pipe 18 is connected to the lower side wall of the extension channel between the filter screen 14 and the inner cavity of the bin. The upper end of the collecting pipe 18 is connected to the interior of the extension channel, and the lower end of the collecting pipe 18 is connected to the extrusion conveying mechanism, the baking device 21 and the grinding mill 23 in sequence.

[0060] A first star-shaped discharge valve 19 is installed between the lower end of the collecting pipe 18 and the feed port of the extrusion conveying mechanism.

[0061] In the drying and air separation equipment, the garbage is in direct contact with the hot fluidized air, which has a high heat transfer efficiency. By controlling the fluidization speed, the garbage is kept in a turbulent state in the fluidization zone, and the mutual collision and friction between the garbage particles can further enhance the heat transfer efficiency.

[0062] Utilizing the density differences between light and heavy waste, the separation of light and heavy components of primary waste is achieved within a single drying and air separation device. Heavy waste flows out of the reactor from the bottom, between the baffle and the reactor wall. Light waste dries in the fluidized bed. As water evaporates, its density decreases. Driven by airflow, it enters the suspended layer, passes through the filter screen, and enters the vertically arranged collection pipe.

[0063] The waste that emerges from the bottom of the dry air separation equipment is heavy waste, primarily consisting of large, non-fluidizable organic waste. In addition, denser materials like metal and stone are also concentrated in the heavy waste. Therefore, the dry air separation equipment has already performed a preliminary sorting of the waste. In the subsequent fine sorting process, only the heavy waste is sorted, thus separating inorganic components like metal and stone from the raw waste, significantly reducing the pressure on the sorting equipment.

[0064] The warehouse can greatly reduce the number of mechanical sorting equipment in the existing process and greatly reduce the failure rate of mechanical equipment, thereby ensuring the stable operation of the project.

[0065] As a further preferred embodiment of the technical solution of embodiment 1 of the present invention, the pneumatic conveying mechanism includes:

[0066] The first garbage crushing unit 2 has its discharge port connected to the throat of the venturi tube 5 through a first pipe. One end of the venturi tube 5 is connected to the outlet of the third fan 4 that conveys 80-100°C, and the other end is connected to the inner cavity of the silo 6 along the tangential direction of the silo wall of a silo 6; a second star-shaped discharge valve 3 is installed on the first pipe.

[0067] As a further preferred embodiment of the technical solution of Example 1 of the present invention, the extrusion conveying mechanism is a variable diameter screw conveyor 20, the diameter of which gradually decreases along the conveying direction. The waste enters the variable diameter screw conveyor 20 for compression, increasing its density. During the compression process, air inside the waste is expelled to ensure an oxygen-free atmosphere required for subsequent baking.

[0068] As a further preferred embodiment of the present invention, the connection end of the venturi tube 5 and the bin body 6 has a downward slope of 1-3 degrees. The delivery pipe where the venturi tube 5 is located has a slope of 1-3 degrees to avoid garbage blockage in the pipe.

[0069] As a further preferred embodiment of the technical solution of Example 1 of the present invention, a rib plate 15 is provided on the inner wall of the hopper located at the air separation layer. By providing the rib plate 15 on the wall, the turbulent kinetic energy of the flow field in the reactor is increased, further strengthening the interphase heat exchange and improving the drying efficiency.

[0070] As a further preferred embodiment of the technical solution in Example 1 of the present invention, the air distribution plate 8 is positioned at an angle of 15-20° with the horizontal, and the baffle 9 is positioned at an angle of 45-60° with the horizontal. Because the air distribution plate is tilted at a certain angle, greater than the repose angle of the domestic waste, heavier domestic waste, loosened by airflow, can fall along the air distribution plate into the narrow gap between the baffle 9 and the wall of the drying and air separation equipment. The air distribution plate and baffle are connected, with a gap between the baffle and the reactor wall, and the baffle is positioned at an angle of approximately 45-60° with the horizontal.

[0071] As a further preferred embodiment of the technical solution of Example 1 of the present invention, a scraping brush that moves periodically is provided on the filter screen.

[0072] The detailed process flow of Example 1 of the present invention is as follows: Raw waste is fed via a conveyor belt to the first waste crushing unit 2 for crushing, resulting in a waste particle size between 20 and 30 mm. The crushed waste is discharged through a second star-shaped discharge valve 3 to the mouth of a venturi tube 5 in the conveying pipe. Pneumatically conveyed by a third blower 4, the crushed waste is transported to a silo 6. The conveying pipe, where the venturi tube 5 is located, has a slope of 1-3° to prevent waste from clogging the pipe.

[0073] The garbage enters the bin body 6 along the tangential nozzle under the action of pneumatic conveying. The tangential injection into the equipment will form a vortex. At the same time, a rib plate 15 is set on the wall of the bin body to enhance the turbulence inside the bin body, thereby enhancing the heat transfer effect between the gas and solid phases.

[0074] Hot air at 100-120°C is introduced into the bottom of the silo by the first fan 24, and the hot air enters the equipment body under the action of the air distribution plate 8. Due to the large differences in the shapes and densities of the various components of the garbage, after entering the silo, the wind speed is controlled to cause the domestic garbage to be stratified in the reactor. The silo can be divided into three layers from bottom to top. The bottom is the sedimentation layer, the middle is the air separation layer, and the top is the suspension layer. Garbage that enters the silo by pneumatic conveying first enters the air separation layer. Heavier components, such as sand, glass, metal and heavy garbage, will gradually settle at the bottom to form a sedimentation layer due to their greater gravity.

[0075] An air distribution plate 8 is installed at the bottom of the drying fluidized bed, angled 15-20° from the horizontal. Because the plate's inclination is greater than the waste's angle of repose, the airflow loosens heavier waste, allowing it to fall along the plate and into the narrow gap between the baffle plate 9 and the wall of the drying and air separation equipment. The plate connects to the baffle, leaving a gap between the baffle plate and the reactor wall. The baffle plate maintains an angle of 45-60° from the horizontal. Heavy waste is discharged from the bin through a third star-shaped discharge valve 10.

[0076] The light waste remains in the air separation layer for a period of time. Within this area, heat exchange occurs between the domestic waste and the high-temperature fluidizing air, causing the temperature to rise and moisture to evaporate. Simultaneously, the collisions between the domestic waste particles enhance the drying effect. During the drying process, the moisture content of the domestic waste gradually decreases, and after its gravity decreases, it becomes light waste and enters the suspension layer. It then flows out of the bin through the light waste outlet 13 under the action of the second fan 17. The waste exits the filter 14 for gas-solid separation. The low-temperature gas is discharged through the filter 14, and the solid waste falls into the collection pipe 18 under the action of gravity.

[0077] A periodically moving scraper is provided on the filter to prevent the filter from being blocked.

[0078] The first star-shaped discharge valve 19 discharges the waste from the collection pipe, simultaneously sealing the entire system. The discharged, relatively dry waste, with a moisture content of approximately 20%, enters the variable-diameter screw conveyor 20 for compression to increase the density of the domestic waste. During the compression process, air is expelled from the waste to ensure an oxygen-free atmosphere required for subsequent roasting. The compressed waste is then fed into a roasting unit 21 for low-temperature roasting at a temperature between 150-250°C and a residence time of approximately 1-2 hours. To ensure temperature uniformity in the roasting unit, thermal oil is used as the heat transfer medium to heat the roasting unit. Heat transfer between the thermal oil and the waste is indirect. This method ensures a relatively uniform temperature within the roasting reactor, with a temperature difference between the thermal oil inlet and outlet of no more than 10°C. The energy required for the roasting unit can be generated by electricity or by the combustion of pyrolysis gases generated during roasting. Low-temperature roasting of the domestic waste produces semi-coke, which is then fed into a pulverizer 23 for grinding. The resulting carbon powder has a particle size of approximately 200-300 μm and can be used as feedstock for entrained or fluidized bed gasification.

[0079] Example 2: This example differs from Example 1 in that it further comprises: an optical screening machine, wherein the bottom of the slit channel is connected to the optical screening machine via a second pipe, and the optical screening machine is used to screen the heavy waste into organic waste and non-organic waste; a third star-shaped discharge valve is installed on the second pipe;

[0080] The second garbage crushing unit is used to crush the organic garbage screened by the optical screening machine again to further reduce the particle size of this part of the garbage; the organic garbage crushed by the second garbage crushing unit is transported to the first garbage crushing unit again through the third pipeline and enters the air separation layer inside the warehouse through the Venturi tube.

[0081] The heavy component garbage coming out of the reactor passes through the optical screening machine to separate the heavy organic garbage from sand, stone and metal substances. The heavy organic garbage is then transported to the second garbage crushing unit for fine crushing to further reduce the particle size of this part of the garbage. After crushing, it is transported to the first garbage crushing unit again and added to the drying and air separation equipment through the Venturi tube.

[0082] After finalization, the design was validated through pilot testing. This pilot test directly treated raw wet garbage with a moisture content of approximately 55%, with a processing capacity of 500 kg / h. Before the experiment, the raw garbage was crushed to a particle size of approximately 20 mm. The experimental process was conducted entirely using the patented technology, with a drying hot air temperature of 160°C. The moisture content and separation performance of the dried garbage were statistically analyzed, as shown in Tables 1 and 2, respectively. As shown in Table 1, the moisture content of the dried garbage met the design target, fluctuating around 20%. As shown in Table 2, after passing through the drying and air separation equipment, approximately 15%-18% of the heavy waste fraction was separated, with a significant increase in the proportion of inorganic materials such as sand and stone in the heavy waste fraction. While the proportion of sand and stone in the raw garbage fraction was approximately 3.5%, after air separation, the proportion of these inorganic materials exceeded 10% of the heavy waste fraction, indicating that the inorganic heavy fraction had been enriched, significantly reducing equipment pressure during subsequent separation.

[0083] Table 1: Measurement of moisture content of garbage after drying

[0084]

[0085] Table 2: Statistics of drying and sorting effects

[0086]

[0087] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A waste hydrogen production pretreatment system, characterized in that: include: The silo body comprises, from bottom to top, a sedimentation layer, an air separation layer, and a suspension layer. A garbage inlet is connected to a silo wall on one side of the silo body corresponding to the air separation layer. The garbage inlet is connected to a pneumatic conveying mechanism. The pneumatic conveying mechanism is provided with a first garbage crushing unit. The garbage crushed by the first garbage crushing unit can be conveyed into the air separation layer in the silo body along the tangential direction of the silo wall through the pneumatic conveying mechanism. A first fan for delivering fluidizing air into the silo is connected to a silo wall on one side of the silo corresponding to the sedimentation layer; an air distribution plate is provided inside the silo above the air outlet of the first fan, one end of the air distribution plate is connected to an inner wall of one side of the silo, and the other end is arranged downwardly and connected to one end of a baffle, the other end of the baffle is connected to the silo bottom, and a narrow slit channel is formed between the baffle and the inner wall on the other side of the silo for the heavy component garbage to be discharged from the silo; A horizontal extension channel is provided on the side of the top of the bin body opposite to the garbage inlet and communicates with the inner cavity of the bin body. The end of the horizontal extension channel is connected to a second fan for inducing air, and a filter is provided in the horizontal extension channel. A vertically arranged material collecting pipe is connected to the lower side wall of the horizontally extending channel between the filter screen and the inner cavity of the bin body. The upper end of the material collecting pipe is connected to the interior of the horizontally extending channel, and the lower end of the material collecting pipe is connected to the extrusion conveying mechanism, the baking equipment and the grinding mill in sequence; A first star-shaped discharge valve is installed between the lower end of the collecting pipe and the feed port of the extrusion conveying mechanism.

2. The waste hydrogen production pretreatment system according to claim 1, characterized in that: The pneumatic conveying mechanism comprises: The first garbage crushing unit has its discharge port connected to the throat of the venturi tube through a first pipe. One end of the venturi tube is connected to the air outlet of the third fan used to send garbage into the air separation layer in the silo, and the other end is connected to the inner cavity of the silo along the tangential direction of the silo wall of a silo; a second star-shaped unloading valve is installed on the first pipe.

3. The waste hydrogen production pretreatment system according to claim 1, characterized in that: The extrusion conveying mechanism is a variable diameter screw conveyor, and the diameter of the variable diameter screw conveyor gradually decreases along the conveying direction.

4. The waste hydrogen production pretreatment system according to claim 2, characterized in that: Also includes: An optical sorting and screening machine, wherein the bottom of the slit channel is connected to the optical sorting and screening machine via a second pipe, and the optical sorting and screening machine is used to screen the heavy waste into organic waste and non-organic waste; a third star-shaped discharge valve is installed on the second pipe; The second garbage crushing unit is used to crush the organic garbage screened by the optical screening machine again to further reduce the particle size of the garbage; The organic waste crushed by the second waste crushing unit is transported again to the first waste crushing unit through the third pipeline and enters the air separation layer inside the bin through the venturi tube.

5. The waste hydrogen production pretreatment system according to claim 2, characterized in that: The connection end of the venturi tube and the bin body has a downward slope of 1-3 degrees.

6. The waste hydrogen production pretreatment system according to claim 1, characterized in that: A rib plate is provided on the inner wall of the bin body located at the air separation layer.

7. The waste hydrogen production pretreatment system according to claim 1, characterized in that: The angle between the air distribution plate and the horizontal direction is 15-20 degrees, and the angle between the baffle and the horizontal direction is 45-60 degrees.

8. The waste hydrogen production pretreatment system according to claim 1, characterized in that: A scraping brush that moves periodically is arranged on the filter screen.

9. A pretreatment process based on the waste hydrogen production pretreatment system according to any one of claims 1 to 8, characterized in that: The original garbage is crushed by the first garbage crushing unit on the pneumatic conveying mechanism. The particle size of the crushed garbage is between 20-30mm. The crushed garbage enters the bin along the tangential nozzle under the pneumatic conveying action of the pneumatic conveying mechanism. The tangential injection into the equipment will form a vortex. The first fan blows hot air at a temperature of no less than 80°C into the bottom of the silo. The hot air enters the silo through the air distribution plate. By controlling the wind speed, the garbage is stratified in the silo. The garbage that enters the silo through pneumatic conveying first enters the air separation layer. The heavier components will gradually settle in the sedimentation layer at the bottom of the silo due to the greater gravity. An air distribution plate is installed at the bottom of the drying fluidized bed. As the air distribution plate is tilted downward, which is larger than the repose angle of domestic waste, the heavier domestic waste will fall into the narrow channel between the baffle and the wall of the silo along the air distribution plate under the loosening effect of the air flow, and the heavy waste will be discharged from the silo. Lightweight waste stays in the air separation layer for a period of time. In the air separation layer, heat exchange occurs between the waste and the fluidized air at a temperature of not less than 80°C, thereby increasing the temperature and evaporating the water. At the same time, the collision between the waste particles will enhance the drying effect. During the drying process, the moisture content of the waste gradually decreases, and the gravity decreases, turning it into light waste and entering the suspension layer. Thereafter, it enters the horizontal extension channel under the action of the induced draft fan, and undergoes gas-solid separation under the action of the filter screen. The low-temperature gas after heat exchange is discharged through the filter screen, and the solid waste falls into the collection pipe under the action of gravity. The moisture content of the garbage in the collecting pipe is 20%-25%. It enters the extrusion conveying mechanism for compression to increase the density of the garbage, and the air inside the garbage is discharged during the compression process to ensure the oxygen-free atmosphere required for subsequent baking. The compressed garbage is sent to the baking equipment for low-temperature baking. The baking temperature is between 150-250℃ and the residence time is 1-2h. Under low-temperature baking, the garbage will produce semi-coke, which is further added to the grinder for grinding. The particle size of the ground carbon powder is 200-300um, which is used as the raw material for entrained bed or fluidized bed gasification.

10. The pretreatment process of the waste hydrogen production pretreatment system according to claim 9, characterized in that: Thermal oil is used as the heat transfer medium in the baking equipment. The heat transfer between the thermal oil and the garbage is indirect. The temperature difference between the inlet and outlet of the thermal oil does not exceed 10°C. The energy required by the baking equipment comes from electricity or the combustion of baking pyrolysis gas.

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