Device and method for photo-thermal preparation of biochar

Abstract

The invention belongs to the technical field of biochar preparation, and particularly relates to photothermal biochar preparation equipment, a furnace body is internally provided with a separation layer, the separation layer is internally provided with a vertical spiral feeding body, the vertical spiral feeding body comprises a rotating shaft and blades which are connected, the rotating shaft is rotatably connected with the furnace body, the blades are in clearance fit with the separation layer, and the rotating shaft and the blades are made of heat conduction materials; the top of the furnace body is provided with a Fresnel condensing lens with a rotatable inclination angle, and the Fresnel condensing lens is used for focusing sunlight to the top end of the rotating shaft; the furnace body comprises a shell, the shell comprises a quartz outer tube, a vacuum layer and a metal inner tube coated with a heat absorption layer from outside to inside, a spiral flow deflector surrounding a partition layer is arranged between the metal inner tube of the shell and the partition layer, and a groove type solar reflector used for converging sunlight to the shell is arranged on one side of the furnace body. The invention aims to effectively reduce the problems of high energy consumption and energy waste in the biochar production process by adopting solar energy as a pyrolysis energy source. The invention also provides a method for photo-thermal preparation of biochar.

Description

Technical Field

[0001] The present invention belongs to the technical field of biochar preparation, and in particular relates to a device and method for preparing biochar by photothermal method. Background Art

[0002] Zhejiang Province is rich in bamboo resources, and it is imperative to further explore the value of bamboo resources. Biochar, especially bamboo charcoal, has a complex pore structure and good surface properties. The porous high carbon content structure makes it have a strong physical adsorption capacity for gas and liquid, and can be converted into activated carbon and other high value-added chemicals. It can be widely used in gas purification, sewage treatment and other fields, and can also be used as a catalyst in the chemical industry and smelting industry.

[0003] At present, most of the technical applications with biochar products as the main purpose use intermittent pyrolysis process, which has the disadvantages of low biochar yield, low production efficiency and economic benefits; while the technology using continuous pyrolysis process has the disadvantages of complex device structure, difficult sealing, high device cost, etc. In addition, the current biochar preparation process mainly uses electricity or fire to provide the energy required for biomass pyrolysis. Its preparation process has problems such as high energy consumption, high cost, and complex equipment, making it difficult to achieve industrial large-scale batch production. Summary of the invention

[0004] The purpose of the present invention is to provide a device and method for preparing biochar by photothermal method, which effectively reduces the high energy consumption and energy waste problems in the biochar production process by adopting solar energy as the energy source for pyrolysis of biochar, and realizes continuous feeding and continuous discharging of biochar with a relatively simple structure, thereby realizing continuous production of biochar.

[0005] In order to achieve the above technical objectives, the technical solution adopted by the present invention is as follows:

[0006] In a first aspect, the present invention provides a device for preparing biochar by photothermal method, comprising a cylindrical furnace body, a smoke outlet is arranged at the top of the furnace body, a discharge port is arranged at the bottom of the furnace body, a partition layer is arranged in the furnace body, the partition layer divides the interior of the furnace body into a carbonization inner zone and a carbonization outer zone, and the carbonization inner zone and the carbonization outer zone are connected at the top of the furnace body; a vertical spiral feed body is arranged in the partition layer, the vertical spiral feed body comprises a connected rotating shaft and blades, the rotating shaft is rotatably connected to the furnace body, the blades are gap-matched with the partition layer, a feeding port penetrating the side wall of the furnace body is arranged on the bottom side wall of the vertical spiral feed body, the rotating shaft and the blades are made of heat-conducting material, a Fresnel focusing lens with a rotatable inclination angle is arranged on the top of the furnace body, and the Fresnel focusing lens is used to focus sunlight on the top of the rotating shaft;

[0007] The furnace body includes a shell, which comprises a quartz outer tube, a vacuum layer and a metal inner tube coated with a heat-absorbing layer from the outside to the inside. A spiral guide plate surrounding the isolation layer is provided between the metal inner tube and the isolation layer of the shell. A trough-type solar reflector for converging sunlight onto the shell is provided on one side of the furnace body.

[0008] Optionally, the feed port is connected to a feed bin for placing granular materials. The feed bin is provided to meet the continuous production requirements, and the feed bin for accumulating granular materials also plays a role in sealing the feed port to a certain extent.

[0009] Optionally, the particle size of the granular material is less than 1 cm. Control of the particle size helps to ensure the pyrolysis carbonization effect.

[0010] Optionally, the flue gas outlet is connected to a one-way valve for connecting to an external flue gas separation and treatment device, so as to collect the flue gas generated during the pyrolysis reaction.

[0011] Optionally, the discharge port is connected to a discharge valve, and a carbon storage tank is provided at the outlet of the discharge valve. The discharge valve is used to seal the discharge port, and the carbon storage tank is used to collect the finished biochar.

[0012] Optionally, the furnace body is arranged on a support, and a motor for driving the rotating shaft to rotate is arranged at the bottom of the support. The motor is used to drive the rotating shaft to rotate, and the retention time of the material in the spiral feed body is controlled.

[0013] Optionally, a dispersion guide plate is provided on the top of the partition layer to help the intermediate biochar after pyrolysis to fall onto the spiral guide plate.

[0014] In a second aspect, the present invention provides a method for preparing biochar by photothermal heat, which is applicable to the device for preparing biochar by photothermal heat as described in the above technical solution, and the method comprises the following steps:

[0015] S1, crush the material into particles, and the material enters the vertical spiral feed body through the feed port;

[0016] S2. Under good lighting conditions, the Fresnel focusing lens focuses on the top of the rotating shaft, so that the vertical spiral feeder forms a high-temperature pyrolysis area and a low-temperature drying area from top to bottom, and the granular material moves from bottom to top in the vertical spiral feeder, gradually moving from the low-temperature drying area to the high-temperature pyrolysis area;

[0017] S3, the trough-type solar reflector focuses sunlight onto the outer shell, so that a low-temperature carbonization and drying area is formed between the metal inner tube and the isolation layer; the carbonized intermediate product of the material moved to the top of the vertical spiral feed body in step S2 falls onto the spiral guide plate and slides downward under the action of gravity;

[0018] S4. Collect the carbonized dry biochar through the discharge port, collect other products through the flue gas outlet, and continuously feed and produce under the condition that light permits.

[0019] The invention adopting the above technical solution has the following advantages:

[0020] 1. The present invention arranges a Fresnel focusing lens to focus sunlight on the top of the rotating shaft, so that the vertical spiral feed body forms a high-temperature pyrolysis area and a low-temperature drying area from top to bottom, that is, a carbonization inner area; a trough-type solar reflector is arranged to focus sunlight on the outer shell, so that a low-temperature carbonization and drying area is formed between the metal inner tube and the partition layer, that is, a carbonization outer area; the granular material moves from bottom to top in the vertical spiral feed body and is gradually dried until it reaches a temperature range suitable for the pyrolysis reaction, and a large amount of products such as biochar are generated. The generated biochar products fall into the low-temperature carbonization and drying area, so that the biochar products are fully carbonized and a stable pore structure is formed. Compared with conventional biochar products, the water content is lower, and its stability and storage life are longer.

[0021] 2. The present invention combines Fresnel focusing lenses and trough-type solar reflectors, utilizes the high conversion rate of Fresnel focusing lenses to provide a heat source for drying and high-temperature pyrolysis, and utilizes the trough-type solar reflectors to provide a uniform low-temperature carbonization and drying heat source, making full use of solar energy as a biochar pyrolysis energy source, effectively reducing the high energy consumption and energy waste problems in the biochar production process, and realizing continuous feeding and continuous discharging of biochar with a relatively simple structure, thereby realizing continuous production of biochar. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention can be further illustrated by the non-limiting examples given in the accompanying drawings;

[0023] Figure 1 This is a schematic diagram of the overall structure of the device in Example 1 of the present invention;

[0024] Figure 2 is a cross-sectional schematic diagram of a furnace body in Example 1 of the present invention;

[0025] Figure 3 This is a flowchart of the steps of the preparation method in Example 2 of the present invention.

[0026] Among them: 1-furnace body, 11-smoke outlet, 12-discharge port, 13-partition layer, 131-feed port, 14-vertical spiral feed body, 141-rotating shaft, 142-blade, 2-Fresnel focusing lens, 15-shell, 151-quartz outer tube, 152-vacuum layer, 153-metal inner tube, 16-spiral guide plate, 3-trough solar reflector, 4-feed bin. DETAILED DESCRIPTION

[0027] The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that in the drawings or descriptions of the specification, similar or identical parts use the same figure numbers, and the implementation methods not shown or described in the drawings are forms known to ordinary technicians in the relevant technical field. In addition, the directional terms mentioned in the embodiments, such as "upper", "lower", "top", "bottom", "left", "right", "front", "back", etc., are only referenced to the directions of the drawings and are not used to limit the scope of protection of the present invention.

[0028] Example 1

[0029] like Figures 1-2 As shown, a photothermal device for preparing biochar of the present invention comprises a cylindrical furnace body 1, the furnace body 1 has a closed hollow cavity, the furnace body 1 is arranged on a support, the furnace body 1 comprises a shell 15, the shell 15 comprises a quartz outer tube 151, a vacuum layer 152 and a metal inner tube 153 coated with a heat absorption layer from outside to inside, a spiral guide plate 16 surrounding the isolation layer 13 is arranged between the metal inner tube 153 of the shell 15 and the isolation layer 13, and a trough solar reflector 3 for converging sunlight onto the shell 15 is arranged on one side of the furnace body 1. The trough solar reflector 3 is rotatably mounted on the mounting frame of the support, and is used to adjust the inclination angle of the trough solar reflector 3, so that the trough solar reflector 3 can adjust the angle with the movement of the sun. In order to realize automatic adjustment, an existing automatic adjustment system such as a thermal radiation meter, a servo motor and a corresponding controller can also be arranged, and the specific structure and principle are not repeated here.

[0030] A flue gas outlet 11 is provided at the top of the furnace body 1, and the flue gas outlet 11 is connected to a one-way valve for connecting to an external flue gas separation and treatment device; a discharge port 12 is provided at the bottom of the furnace body 1, and the tail end of the spiral guide plate 16 is aligned with the discharge port 12, and the discharge port 12 is connected to a discharge valve, and a charcoal storage tank is provided at the outlet of the discharge valve, and the discharge of biochar is controlled by the discharge valve. The discharge port 12 can also be provided with a flap structure, which includes a rotatable flap, and a spring is connected to the bottom of the flap. When the weight of the biochar falling on the flap exceeds the preset elastic force of the flap, the flap opens downward to realize discharge; when the amount of biochar generated is insufficient, the flap remains in a horizontal closed state under the action of the spring to maintain the airtight state of the furnace body 1.

[0031] A partition layer 13 is provided in the furnace body 1. The partition layer 13 is cylindrical and is arranged coaxially with the furnace body 1. The partition layer 13 divides the interior of the furnace body 1 into a carbonization inner zone and a carbonization outer zone. A dispersion guide plate is provided on the top of the partition layer 13. The carbonization inner zone and the carbonization outer zone are connected at the top of the partition layer 13. A spiral feeder 14 is provided in the partition layer 13. The spiral feeder 14 includes a connected rotating shaft 141 and a blade 142. The blade 142 is spirally wound around the rotating shaft 141 by welding. The rotating shaft 141 is rotatably connected to the furnace body 1. A motor for driving the rotating shaft 141 to rotate is provided at the bottom of the support. The blade 142 is in gap fit with the partition layer 13. A feed port 131 penetrating the side wall of the furnace body 1 is provided on the bottom side wall of the partition layer 13. The feed port 131 is connected to a feed bin 4 for placing granular materials. The particle size of the granular materials is less than 1 cm, but the particle size is greater than the gap distance between the blade 142 and the partition layer 13. It is understandable that the feed port 131 can adopt a smooth pipe with an inclined setting so that the material in the feed bin 4 slides to the spiral feed body 14, or an existing spiral feeder can be used to ensure stable feeding and control the feeding speed.

[0032] The rotating shaft 141 and the blades 142 are made of heat-conducting materials, such as heat-resistant metals or alloys such as copper and aluminum. A Fresnel focusing lens 2 with a rotatable inclination angle is provided on the top of the furnace body 1. The Fresnel focusing lens 2 is used to focus sunlight onto the top of the rotating shaft 141; specifically, the Fresnel focusing lens 2 is rotatably mounted on a mounting frame on the top of the furnace body 1, and is used to adjust the inclination angle of the Fresnel focusing lens 2, so that the Fresnel focusing lens 2 can adjust its angle as the sun moves. In order to achieve automatic adjustment, an existing thermal radiation meter, a servo motor and a corresponding controller and other automatic adjustment systems can also be set. The specific structure and principle will not be repeated here.

[0033] The carbonization inner zone includes a low-temperature drying zone and a high-temperature pyrolysis zone. Specifically, the Fresnel focusing lens 2 focuses sunlight to the top of the rotating shaft 141, so that the end of the entire spiral feed body 14 close to the top becomes a high-temperature pyrolysis zone with a higher temperature, and the end away from the top becomes a low-temperature drying zone with a relatively low temperature. The granular material moves slowly from bottom to top in the spiral feed body 14, and gradually moves from the low-temperature drying zone to the high-temperature pyrolysis zone. After the biomass material enters the spiral feed body 14 from the feed port 131, it is slowly transported upward with the rotating blades 142, and is initially dried and dehydrated from the low-temperature drying zone at the bottom. When it reaches the high-temperature pyrolysis zone, the biomass raw material is carbonized in large quantities, and the generated flue gas is discharged from the flue gas outlet 11 to the external flue gas separation and treatment equipment to obtain biogas, wood vinegar, wood tar and other products. The generated biochar accumulates on the top of the spiral feed body 14 and falls onto the spiral guide plate 16 through the dispersion guide plate provided on the top of the partition layer 13.

[0034] The carbonized outer zone includes a low-temperature carbonization and drying area. Specifically, since a trough-type solar reflector 3 for converging sunlight onto the shell 15 is provided on one side of the furnace body 1, the trough-type solar reflector 3 converges sunlight onto the outer shell, so that a low-temperature carbonization and drying area is formed between the metal inner tube 153 and the isolation layer 13. The biochar falling onto the spiral guide plate 16 slowly slides downward under the action of gravity, which increases the retention time of the biochar and allows the biochar to be fully carbonized and dried.

[0035] It can be understood that in this embodiment, in order to ensure that the preparation process conditions of biochar meet the requirements, in this embodiment, three existing temperature sensors are also provided on the furnace body 1, which are respectively arranged at the top, middle and bottom of the furnace body 1. The temperature sensors are electrically connected to the existing controller for detecting the temperature of each area. The number of temperature sensors can be adjusted according to actual conditions.

[0036] It can be understood that, in the present embodiment, the furnace body 1 and the spiral feed body 14 are arranged in a vertical state, but based on the characteristics of such existing spiral feed bodies, in some other embodiments, when the Fresnel focusing lens 2 and the trough-type solar reflector 3 are synchronously adjusted in angle, the spiral feed body 14 can also be arranged in an inclined state, and its maximum inclination angle is limited to the extent that the biochar falling on the spiral guide plate 16 can still slide slowly downward under the action of gravity.

[0037] Example 2

[0038] like Figure 3 As shown, a method for preparing biochar by photothermal method of the present invention is applicable to the device for preparing biochar by photothermal method in any one of Embodiment 1, and the method comprises the following steps:

[0039] S1. The material is crushed into particles, and the material enters the spiral feed body 14 through the feed port 131; the biomass raw material, such as bamboo that meets the requirements, is first crushed, and the particle size is controlled to be less than 1 cm; the material is accumulated in the feed bin 4, the feed bin 4 can be sealed, and the discharge port 12 is connected to a normally closed discharge valve, so that the interior of the furnace body 1 becomes an anaerobic pyrolysis reaction place that is almost isolated from air;

[0040] S2. Under good lighting conditions, the Fresnel focusing lens 2 focuses sunlight on the top of the rotating shaft 141, so that the spiral feed body 14 forms a high-temperature pyrolysis area and a low-temperature drying area from top to bottom, and the granular material moves from bottom to top in the spiral feed body 14, and gradually moves from the low-temperature drying area to the high-temperature pyrolysis area; since the heat source at the top of the rotating shaft 141 is conducted to the bottom, there must be a certain loss, so that the temperature of the entire spiral feed body 14 rises from bottom to top, and the granular material moves from bottom to top in the spiral feed body 14 and is gradually dried until it reaches a temperature range suitable for pyrolysis reaction, and when it reaches the top of the spiral feed body 14, a large amount of products such as biochar are generated;

[0041] S3, the trough type solar reflector 3 focuses sunlight onto the outer shell, so that a low-temperature carbonization and drying area is formed between the metal inner tube 153 and the isolation layer 13; the carbonized intermediate product of the material moved to the top of the spiral feed body 14 in step S2 falls onto the spiral guide plate 16 and slides downward under the action of gravity; the ordinary trough type solar reflector has a heat collection peak temperature lower than that of the Fresnel focusing lens, but its heat collection is more uniform, so the uniform low-temperature carbonization and drying area formed between the metal inner tube 153 and the isolation layer 13 makes the biochar product fully carbonized and forms a stable pore structure, and compared with conventional biochar products, the moisture content is lower, and its stability and storage life are longer.

[0042] S4. The carbonized and dried biochar is collected through the discharge port 12, and other products are collected through the flue gas outlet 11. The feed is continuously fed and the production is continuous when light is permitted.

[0043] The method in this embodiment is applicable to the equipment in Example 1, so that by using solar energy as the energy source for biochar pyrolysis, the high energy consumption and energy waste problems in the biochar production process can be effectively reduced. With a relatively simple structure, continuous feeding and continuous discharging of biochar can be achieved, thereby realizing continuous production of biochar.

[0044] The above is a detailed introduction to a device and method for preparing biochar by photothermal method provided by the present invention. The description of the specific embodiment is only used to help understand the method and its core idea of ​​the present invention. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A device for preparing biochar by photothermal method, comprising a cylindrical furnace body (1), a smoke outlet (11) being provided at the top of the furnace body (1), and a discharge port (12) being provided at the bottom of the furnace body (1), characterized in that: A partition layer (13) is provided in the furnace body (1), and the partition layer (13) divides the interior of the furnace body (1) into a carbonization inner zone and a carbonization outer zone, and the carbonization inner zone and the carbonization outer zone are connected at the top of the furnace body (1); a spiral feeder (14) is provided in the partition layer (13), and the spiral feeder (14) comprises a connected rotating shaft (141) and blades (142), and the rotating shaft (141) is rotatably connected to the furnace body (1), The blades (142) are fitted with a gap between the insulating layer (13); the bottom side wall of the spiral feed body (14) is provided with a feed port (131) penetrating the side wall of the furnace body (1); the rotating shaft (141) and the blades (142) are made of heat-conducting material; the top of the furnace body (1) is provided with a Fresnel focusing lens (2) with a rotatable inclination angle; the Fresnel focusing lens (2) is used to focus sunlight onto the top of the rotating shaft (141); The furnace body (1) comprises a shell (15), wherein the shell (15) comprises, from outside to inside, a quartz outer tube (151), a vacuum layer (152), and a metal inner tube (153) coated with a heat absorption layer; a spiral guide plate (16) surrounding the isolation layer (13) is provided between the metal inner tube (153) of the shell (15) and the isolation layer (13); and a trough-type solar reflector (3) for converging sunlight onto the shell (15) is provided on one side of the furnace body (1).

2. The device for preparing biochar by photothermal method according to claim 1, characterized in that: The feed port (131) is connected to a feed bin (4) for placing granular materials.

3. The device for preparing biochar by photothermal method according to claim 2, characterized in that: The particle size of the granular material is less than 1 cm.

4. The device for preparing biochar by photothermal method according to claim 1, characterized in that: The smoke outlet (11) is connected to a one-way valve for connecting to external smoke separation and treatment equipment.

5. The device for preparing biochar by photothermal method according to claim 1, characterized in that: The discharge port (12) is connected to a discharge valve, and a carbon storage tank is provided at the outlet of the discharge valve.

6. The device for preparing biochar by photothermal method according to claim 1, characterized in that: The furnace body (1) is arranged on a support, and a motor for driving the rotating shaft (141) to rotate is arranged at the bottom of the support.

7. The device for preparing biochar by photothermal method according to claim 1, characterized in that: A dispersion guide plate is provided on the top of the partition layer (13).

8. A method for preparing biochar by photothermal method, applicable to the device for preparing biochar by photothermal method as claimed in any one of claims 1 to 7, characterized in that: The method comprises the following steps: S1, crushing the material into particles, and the material enters the spiral feed body (14) through the feed port (131); S2. Under good lighting conditions, the Fresnel focusing lens (2) is focused on the top of the rotating shaft (141), so that the spiral feed body (14) forms a high-temperature pyrolysis area and a low-temperature drying area from top to bottom, and the granular material moves from bottom to top in the spiral feed body (14), and gradually moves from the low-temperature drying area to the high-temperature pyrolysis area; S3, the trough-type solar reflector (3) focuses sunlight onto the outer shell, so that a low-temperature carbonization and drying area is formed between the metal inner tube (153) and the isolation layer (13); the carbonized intermediate product of the material moved to the top of the spiral feed body (14) in step S2 falls onto the spiral guide plate (16) and slides downward under the action of gravity; S4. The dry biochar after carbonization is collected through the discharge port (12), and other products are collected through the flue gas outlet (11). The feed is continuously fed and the production is continuous when light is permitted.

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