Biomass continuous carbonization kiln and application thereof

Abstract

The invention relates to the technical field of biomass carbonization, in particular to a biomass continuous carbonization kiln based on a double-layer rotary kiln structure and application of the biomass continuous carbonization kiln. A biomass continuous carbonization kiln comprises a rotary kiln body, a heating box body and a sealing system. According to the invention, preheating and carbonization are carried out in sections through the inner and outer layer guide plates, the carbonization time is prolonged by 30%, and the product yield is improved by 15%; oxygen permeation is controlled through triple sealing, the deflagration risk is reduced, and safety is good; heat energy closed-loop utilization: flue gas purification, tail gas backdraft and waste heat drying are integrated, comprehensive energy consumption is reduced by 25%, flue gas waste heat is fully recycled, heat energy is utilized in a stepped mode, energy consumption is low, and environment-friendly production is achieved; the explosion-proof device is linked with the cooling system, so that the problem of passive protection only depending on buffer filler in the prior art is effectively solved, and the safety controllability is high.

Description

Technical Field

[0001] The present invention relates to the technical field of biomass carbonization, and particularly relates to a biomass continuous carbonization kiln based on a double-layer rotary kiln structure and its application. Background Art

[0002] Biomass carbonization technology mainly converts biomass into high-value biochar, combustible gas and heat energy through pyrolysis. In the prior art, most carbonization devices are intermittent kilns or single-layer rotary kilns. In the actual production process, the following problems exist: 1. Low carbonization efficiency: The intermittent kiln needs to feed and discharge materials frequently, with a long cycle and limited production capacity. 2. Insufficient heat energy utilization: The waste heat of the flue gas is not fully recovered, and some equipment only undergoes simple combustion treatment without realizing cascade utilization. 3. Difficult oxygen content control: The design of the micro-negative pressure or micro-positive pressure system is imperfect, which is likely to cause oxygen infiltration and pose a risk of deflagration. 4. Safety defects: Improper treatment of carbonization tail gas or lack of explosion-proof devices pose safety hazards. Summary of the Invention

[0003] In view of the technical defects mentioned in the background art, the present invention provides a biomass continuous carbonization kiln based on a double-layer rotary kiln structure. By optimizing the material flow path, heat energy utilization and safety control, the present invention realizes the efficient and continuous carbonization of biomass, and at the same time solves the problems of high energy consumption, low carbonization efficiency, difficult oxygen content control and safety hazards existing in the prior art.

[0004] To achieve the above technical objectives, the technical solution adopted by the present invention is: a biomass continuous carbonization kiln, comprising a rotary kiln body, a heating box body, and a sealing system; a spiral feeding mechanism is arranged at the head end of the rotary kiln body, a set of roller support mechanisms for realizing the rotation of the rotary kiln body is sleeved on the rotary kiln body, and is respectively arranged on both sides of the heating box body, and each roller support mechanism is equipped with a driving device; it also includes an explosion-proof mechanism and a waste heat recovery and utilization module; The double-layer structure sleeved inside and outside the rotary kiln body includes an inner layer channel and an outer layer channel; inner layer channel guide plates and outer layer channel guide plates are evenly distributed on the inner side walls of the inner layer channel and the outer layer channel, and the inclination directions of the inner and outer layer channel guide plates are opposite; An inlet is installed on the spiral feeding mechanism; the outside of the output end of the spiral feeding mechanism is connected to a discharge gas collecting hood through a connecting piece, and the discharge gas collecting hood is sleeved outside the head end of the rotary kiln body; The heating box body is arranged in the middle of the rotary kiln body and is movably wrapped outside the rotary kiln body; a burner group is arranged at the lower part of the heating box body; The explosion-proof mechanism includes a pressure relief explosion-proof valve, which is installed at the tail end of the rotary kiln body; The waste heat recovery module includes a heat exchanger, a flue gas pipeline and a combustible gas pipeline; one end of the flue gas pipeline is connected to the hot flue gas pipeline on the top of the heating box, and after passing through the heat exchanger, the other end of the flue gas pipeline is connected to the drying bin; one end of the combustible gas pipeline is connected to the combustible gas outlet on the top of the discharge gas collecting hood, and the other end is connected to the burner at the bottom of the heating box.

[0005] As a preferred technical solution: the guide plates of the inner and outer channels are both arranged in multi-threaded segmented spirals, and the two directions are opposite; in the rotary kiln body, the material falls freely from the kiln head to the kiln tail of the inner channel to the kiln tail of the outer channel, and then is transported from the kiln tail of the outer channel to the kiln head of the outer channel.

[0006] As a preferred technical solution: the micro-negative pressure system includes an oxygen content sensor and an induced draft fan; the oxygen content sensor is arranged on the discharge air collecting hood, and the induced draft fan is arranged on the rear end pipeline of the discharge air collecting hood outlet; the oxygen content sensor and the induced draft fan are interlocked and controlled to control the oxygen concentration to be ≤5%.

[0007] As a preferred technical solution: a first sealing mechanism is installed on the discharge gas collecting hood to achieve sealing between the discharge gas collecting hood and the outer side of the rotary kiln body; the first sealing mechanism includes a plurality of layered sealing plates and graphite blocks evenly distributed along the circumference of the side port of the discharge gas collecting hood; the graphite blocks are evenly distributed along the circumference of the outer side surface of the rotary kiln body; the layered sealing plate, the upper end of which is connected to the discharge gas collecting hood, and the lower end of which overlaps the upper surface of the graphite block on the outer circumference of the rotary kiln body.

[0008] As a preferred technical solution: a second sealing mechanism is arranged on both side end faces of the heating box to achieve sealing between the heating box and the outer side of the rotary kiln body; the second sealing mechanism includes a plurality of layered sealing plates evenly distributed along the circumference of the side port of the discharge gas collecting hood; the layered sealing plate, the upper end of which is connected to the side of the heating box, and the lower end of which overlaps the outer side of the rotary kiln body.

[0009] As a preferred technical solution: the layered sealing plates are fish scales, silicon-aluminum composite plates, and fish scales from top to bottom; one end is fixed to the side of the discharge gas collecting hood or the circumferential inclined plates at both ends of the heating box through a connector, and the other end is overlapped on the rotary kiln body; its outer side is tightened by a steel wire rope, and the entire sealing structure is tightly held by a counterweight hammer.

[0010] As a preferred technical solution: the lower part of the discharge gas collecting hood wrapped around the kiln head end of the rotary kiln body is the carbonized particle outlet, which is connected to the water-cooling spiral mechanism. The biochar is cooled by the water-cooling spiral mechanism, and the water-cooling spiral machine and the inside of the kiln body also maintain an oxygen-free and slightly negative pressure.

[0011] As a preferred technical solution: the explosion-proof mechanism is installed on the outside of the kiln tail end of the rotary kiln body, including a pressure relief explosion-proof valve, and an aluminum sheet with a thickness of 2-5 mm is used as a pressure relief point at the kiln tail position.

[0012] As a preferred technical solution: the head end of the inner channel of the rotary kiln body extends out of the head end of the outer channel, and the discharge gas collecting hood is arranged outside the ends of the two; the output end of the spiral feeding mechanism passes through the side wall of the discharge gas collecting hood and extends into the inner channel of the rotary kiln body.

[0013] The application of a biomass continuous carbonization kiln is carried out according to the following steps: S1. Equipment preparation The equipment starts, the burner heats the rotary kiln body, and the temperature inside the kiln body rises to the set temperature; S2, preheating stage The dried biomass pellets are fed into the inner channel through the feed port of the spiral feeder mechanism, and are transported from the kiln head to the kiln tail through the inner channel guide plate. The whole process preheats the materials to 200-300℃. S3, Carbonization stage The materials in the inner channel fall into the outer channel at the rear end of the kiln, and the guide plate of the outer channel transports the materials from the rear end of the kiln to the front end of the kiln. The burner in the heating box continuously heats the outer channel to generate biochar and combustible gas. S4. Exhaust gas treatment After dust removal and condensation, part of the combustible gas returns to the burner for heating; the other part is used for drying or storage of raw materials or for other purposes; S5. Product Collection A water-cooling spiral mechanism is installed at the outlet of the carbonized particles. The biochar is cooled by the water-cooling spiral mechanism. The water-cooling spiral mechanism maintains an oxygen-free and slightly negative pressure like the inside of the rotary kiln. The cooled biochar is packaged and stored. Compared with the prior art, the present invention has the following beneficial effects: 1. Double-layer material guide structure: The present invention realizes preheating and carbonization in stages through inner and outer material guide plates, which prolongs the carbonization time by 30% and increases the product yield by 15%; 2. Micro-negative pressure collaborative sealing: The present invention controls oxygen infiltration through triple sealing, reduces the risk of explosion, and has good safety; 3. Closed-loop utilization of heat energy: integrating flue gas purification, exhaust gas backfire and waste heat drying, reducing comprehensive energy consumption by 25%, fully recovering and reusing flue gas waste heat, step-by-step utilization of heat energy, low energy consumption and environmentally friendly production; 4. Modular safety design: The explosion-proof device is linked with the cooling system, which effectively solves the passive protection problem of existing technologies that only rely on buffer fillers, and has strong safety and controllability. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the structure of the present invention (the water-cooling spiral mechanism is not shown).

[0015] Figure 2 This is the enlarged detail view in the present invention.

[0016] Figure 3 This is the schematic diagram of the pipeline layout in the present invention.

[0017] Figure 4 is the schematic diagram of the layout position of the water-cooled spiral mechanism in the present invention.

[0018] Figure 5 is Figure 4 the schematic diagram in the A-A direction in

[0019] In the figure: 1 - spiral feeding mechanism, 1-1 feeding port, 2 - discharge gas collecting hood, 2-1 combustible gas outlet, 2-2 carbonized particle outlet, 3-1 first sealing device, 3-2 second sealing mechanism, 4 - rotary kiln body, 4-1 inner layer channel, 4-2 outer layer channel, 4-3 inner layer channel guide plate, 4-4 outer layer channel guide plate, 5 - driving device, 6 - roller support mechanism, 7 - heating box, 7-1 heating box hot flue gas pipeline, 7-2 burner, 8 - explosion-proof mechanism, 9 - water-cooled spiral mechanism, 10 - oxygen content sensor, 11 - temperature sensor. Detailed implementation manners

[0020] The following further describes the present invention with reference to the drawings and embodiments.

[0021] Refer to the attached Figures 1-5 As shown in the figure, the biomass continuous carbonization kiln disclosed by the present invention includes a rotary kiln body 4, a heating box 7, and a sealing system. The spiral feeding mechanism 1 is arranged at the head end of the rotary kiln body 4. A set of roller support mechanisms 6 for realizing the rotation of the rotary kiln body are sleeved on the rotary kiln body 4, and are respectively arranged on both sides of the heating box 7. Each roller support mechanism 6 is equipped with a driving device 5; it also includes an explosion-proof mechanism 8 and a waste heat recovery and utilization module.

[0022] As a preferred embodiment, the entire double-layer structure of the rotary kiln body is supported by two sets of roller support mechanisms before and after and realizes rotation. The rollers in the roller support mechanism are sleeved on the outside of the rotary kiln body 4, and the driving device drives the idler wheels, and the idler wheels drive the rollers to rotate.

[0023] As a preferred technical solution, the rotary kiln body 4 is a double-layer structure with an inner and outer sleeve, including an inner layer channel 4-1 and an outer layer channel 4-2. The diameter of the inner layer channel is smaller than that of the outer layer channel. Inner layer channel guide plates 4-3 and outer layer channel guide plates 4-4 are uniformly distributed on the inner side walls of the inner layer channel 4-1 and the outer layer channel 4-2. The inclination directions of the inner and outer layer channel guide plates are opposite, as shown in Figure 1The rotary kiln body 4 is divided into an inner layer (preheating section) and an outer layer (carbonization section), and the material flow direction is controlled by respective guiding plates; the guiding plates of the inner and outer layer channels are both arranged in a multi-threaded segmented spiral shape, and the two have opposite directions; the material in the rotary kiln body falls freely from the kiln head to the kiln tail of the inner layer channel, then to the kiln tail of the outer layer channel, and is then pushed and conveyed from the kiln tail of the outer layer channel to the kiln head of the outer layer channel, extending the carbonization time and improving the carbonization uniformity.

[0024] A feed inlet 1-1 is installed on the spiral feeding mechanism 1; the outer side of the output end of the spiral feeding mechanism 1 is connected to the discharge gas collecting hood 2 through connecting parts such as flanges and bolts, and the discharge gas collecting hood 2 is sleeved outside the kiln head end of the rotary kiln body 4. The head end of the inner layer channel 4-1 of the rotary kiln body 4 extends out of the head end of the outer layer channel 4-2, and the discharge gas collecting hood 2 covers the outside of the ends of both. The output end of the spiral feeding mechanism 1 passes through the side wall of the discharge gas collecting hood 2 and extends into the inner layer channel 4-1 of the rotary kiln body 4. A first sealing mechanism 3-1 is installed on the discharge gas collecting hood 2 to achieve the sealing between the discharge gas collecting hood 2 and the outside of the rotary kiln body 4.

[0025] As a preferred embodiment, the first sealing mechanism 3-1 includes a plurality of layered sealing plates and graphite blocks 3-4 evenly distributed along the circumference of the side port of the discharge gas collecting hood 2. The graphite blocks 3-4 are the bottom layer and are evenly distributed along the circumference of the outer side of the rotary kiln; the layered sealing plates, the upper end of which is connected to the discharge gas collecting hood 2, and the lower end of which overlaps with the upper surface of the graphite blocks 3-4.

[0026] The heating box body 7 is arranged in the middle of the rotary kiln body 4, and the whole heating box body 7 is wrapped outside the rotary kiln body, and both ends are ensured to prevent the hot flue gas from leaking through the second sealing mechanism. A burner group 7-2 is arranged at the lower part of the heating box body 7, and a hot oxygen pipeline 7-1 is arranged at the top of the heating box body 7. Second sealing mechanisms 3-2 are arranged on both side end faces of the heating box body 7 to achieve the sealing between the heating box body 7 and the outside of the rotary kiln body 4. The second sealing mechanism 3-2 includes layered sealing plates evenly distributed along the circumference of the side port of the discharge gas collecting hood 2. Among the layered sealing plates, the upper layer is fish scale pieces 3-5, the middle layer is a silicon-aluminum composite plate 3-3, and the lower layer is fish scale pieces 3-5. Using the fish scale pieces 3-5 in the lower layer can enhance the wear resistance of the sealing structure and improve the service life of the sealing device. One end of the three is fixed to the circumferential inclined plates at both ends of the heating box body 7 through bolts, and the other end is lapped on the rotary kiln body 4, and the three are held tightly against the rotary kiln body through steel wires and counterweight hammers. The heating box body 7 is internally filled with a certain thickness of heat insulation cotton to reduce the heat transfer from the inside of the box body to the outside. There is a hot flue gas pipeline 7-1 at the upper part of the heating box body 7 for discharging the hot flue gas in the box body.

[0027] As a preferred embodiment, the layered sealing plates are fish scales 3-5, silicon-aluminum composite plates 3-3, and fish scales 3-5 from top to bottom. One end of the layered sealing plates is fixed to the circumferential inclined plates at both ends of the heating box 7 by bolts and other connectors, and the other end is overlapped on the rotary kiln body 4; the outer side of the layered sealing plates is fastened by steel wire ropes, and the whole sealing structure is tightly held by the rotary kiln body 4 by a counterweight hammer.

[0028] The micro-negative pressure system includes an oxygen content sensor 10 and an induced draft fan; the oxygen content sensor 10 is arranged on the discharge gas collecting hood 2, and the induced draft fan is arranged on the rear end pipeline of the discharge gas collecting hood outlet 2, so as to extract the combustible gas generated by the carbonization reaction from the discharge gas collecting hood 2 and send it to the burner or other purposes; the oxygen content sensor and the induced draft fan are interlocked and controlled to control the oxygen concentration to be maintained at ≤5%.

[0029] The lower part of the discharge gas collection hood 2 wrapped around the kiln head end of the rotary kiln body 4 is the carbonized particle outlet 2-2, which is connected to the water-cooling spiral mechanism 9. The biochar is cooled by the water-cooling spiral mechanism 9, and the water-cooling spiral mechanism 9 and the inside of the kiln body also maintain an oxygen-free and slightly negative pressure. The discharge gas collection hood 2 completely wraps the kiln head part of the rotary kiln body 4. The materials coming from the outer channel fall from the kiln head part. The lower part of the discharge gas collection hood 2 is a prism structure, which is larger at the top and smaller at the bottom. It collects the materials falling from the kiln head part. The end of the carbonized particle outlet 2-2 at the lower part of the discharge gas collection hood 2 is welded with a square flange. The flange is connected to the feed port flange of the water-cooling spiral mechanism 9 with bolts and other connectors. The material directly enters the water-cooling spiral mechanism from the outlet of the discharge gas collection hood 2, so that an oxygen-free and slightly negative pressure environment can be maintained.

[0030] The heating box 7 outside the kiln body has multiple burners 7-2 built in it. When the equipment is initially working, it needs external combustible gas (such as natural gas) to burn to provide a heat source. After the biomass starts to carbonize, the combustible gas (such as CO, CH4) produced is sent to the burner through the fan to burn, providing a heat source for biomass carbonization. After purification, part of the carbonized tail gas is returned to the combustion chamber for recycling, and the remaining tail gas is used to dry the biomass raw materials, realizing the cascade utilization of thermal energy.

[0031] The rotary kiln body 4 and the discharge gas collecting hood 22 use a triple sealing structure consisting of fish scales + silicon-aluminum composite plates + fish scales + graphite blocks to maintain a slight negative pressure (-10~-50 Pa) in the kiln and inhibit oxygen infiltration. The oxygen content sensor monitors in real time and adjusts the frequency of the induced draft fan in a linked manner to ensure that the oxygen concentration is less than 5%.

[0032] The explosion-proof mechanism 8 includes a pressure relief explosion-proof valve, which is installed outside the tail end of the rotary kiln body 4. At the tail end of the kiln, an aluminum sheet with a thickness of 2-5 mm is used as the pressure relief point. The aluminum sheet on the explosion-proof valve is very thin and has a cross line drawn in the middle. When an explosion occurs inside the kiln, due to the low strength of the aluminum sheet, it will burst first, quickly relieve the pressure, prevent other parts of the equipment from being damaged, and control the bursting direction and pressure relief path through the above structural design. Using an aluminum sheet with a suitable thickness as the pressure relief point can not only meet the structural strength of a slightly negative pressure inside the kiln but also burst instantly when deflagration occurs in the system, quickly releasing the pressure. This pressure relief explosion-proof valve has a fast response speed and good sealing performance. By controlling the bursting direction and pressure relief path through the structural design, secondary injuries can be avoided. When deflagration occurs in the system, it can quickly release the pressure and prevent the overall explosion of the system.

[0033] The waste heat recovery module includes a heat exchanger, a flue gas gas transmission pipeline, and a combustible gas gas transmission pipeline; one end of the flue gas gas transmission pipeline is connected to the hot flue gas pipeline 7-1 at the top of the heating box body 7. After passing through the heat exchanger, the other end of the flue gas gas transmission pipeline is connected to the drying bin; one end of the combustible gas gas transmission pipeline is connected to the combustible gas outlet 2-1 at the top of the discharge gas collection hood 2, and the other end is connected to the burner 7-2 at the lower part of the heating box body 7. The carbonized biochar is cooled to below 40°C by a water-cooled screw conveyor to avoid spontaneous combustion. The combustion flue gas heats the air through the heat exchanger for drying biomass particles, reducing the moisture content of the raw material to below 15% and improving the carbonization efficiency. The lower part of the discharge gas collection hood 2 is installed with a water-cooled screw to cool the carbonized biochar and prevent the biochar from spontaneous combustion at high temperatures.

[0034] The working process of the present invention is as follows: S1. Equipment preparation The equipment is started, and the burner 7-2 is ignited to heat the rotary kiln body 4 until the set temperature is reached inside the kiln. S2. Preheating stage The biomass particle material after drying (moisture content ≤ 15%) is fed into the inner channel 4-1 through the feed inlet 1-1 of the screw feeding mechanism 1, and the material is sent from the head end of the kiln to the tail end through the inner channel deflector 4-3. During the whole process, the material is preheated to 200-300°C. S3. Carbonization stage The material in the inner channel 4-1 falls into the outer channel 4-2 at the tail end of the kiln, and the material is conveyed from the tail end to the head end again by relying on the outer channel deflector 4-4. The burner 7-2 in the heating box body 7 continuously heats the outer channel 4-2, and carbonization occurs at 500-800°C for about 20 minutes to generate biochar and combustible gas. S4. Tail gas treatment After the combustible gas is dust-removed and condensed, about 40% of it is returned to the burner 7-2 in the heating box 7 to heat the rotary kiln body 4, and the remaining about 60% can be used for raw material drying or storage or for other purposes. The hot flue gas in the heating box 7 is transported through the hot flue gas pipe 7-1 above to the external air heat exchanger. After heat exchange, the flue gas is discharged after dust removal and purification, and the hot air can be used for drying raw materials or for other purposes.

[0035] S5. Product collection A water-cooled spiral mechanism is installed at the position of the carbonized particle outlet 2-2. The biochar is cooled by the water-cooled spiral mechanism. The water-cooled spiral mechanism, like the inside of the rotary kiln body 4, maintains an anaerobic and slightly negative pressure to prevent the high-temperature biomass carbon from spontaneous combustion. The cooled biomass carbon is packaged and stored.

Claims

1. A biomass continuous carbonization kiln, comprising a rotary kiln body, a heating box body, and a sealing system; a spiral feeding mechanism is arranged at the head end of the rotary kiln body, a set of ring support mechanisms for realizing the rotation of the rotary kiln body is sleeved on the rotary kiln body, and they are respectively arranged on both sides of the heating box body, and each ring support mechanism is equipped with a driving device; characterized in that: It also includes explosion-proof mechanism and waste heat recovery module; The rotary kiln body has a double-layer structure with inner and outer layers, including an inner channel and an outer channel; inner channel guide plates and outer channel guide plates are evenly distributed on the inner side walls of the inner channel and the outer channel, and the inner and outer channel guide plates are inclined in opposite directions; The spiral feeding mechanism is provided with a feeding port; the outer side of the output end of the spiral feeding mechanism is connected to the discharge gas collecting hood through a connecting piece, and the discharge gas collecting hood is sleeved on the outer side of the kiln head end of the rotary kiln body; The heating box is arranged in the middle of the rotary kiln body and is movably wrapped around the outer side of the rotary kiln body; a burner group is arranged at the lower part of the heating box; The explosion-proof mechanism includes a pressure relief explosion-proof valve installed at the kiln tail end of the rotary kiln body; The waste heat recovery module includes a heat exchanger, a flue gas pipeline and a combustible gas pipeline; one end of the flue gas pipeline is connected to the hot flue gas pipeline on the top of the heating box, and after passing through the heat exchanger, the other end of the flue gas pipeline is connected to the drying bin; one end of the combustible gas pipeline is connected to the combustible gas outlet on the top of the discharge gas collecting hood, and the other end is connected to the burner at the bottom of the heating box.

2. The biomass continuous carbonization kiln according to claim 1, wherein: The guide plates of the inner and outer channels are arranged in multi-threaded segmented spirals in opposite directions. Inside the rotary kiln body, the materials fall freely from the kiln head to the kiln tail of the inner channel to the kiln tail of the outer channel, and then are transported from the kiln tail of the outer channel to the kiln head of the outer channel.

3. The biomass continuous carbonization kiln according to claim 1, characterized in that: The micro-negative pressure system comprises an oxygen content sensor and an induced draft fan; the oxygen content sensor is arranged on the discharge air collecting hood, and the induced draft fan is arranged on the rear end pipeline of the discharge air collecting hood outlet; the oxygen content sensor and the induced draft fan are interlocked and controlled to control the oxygen concentration to be ≤5%.

4. The biomass continuous carbonization kiln according to claim 1, wherein: A first sealing mechanism is installed on the discharge gas collecting hood to achieve sealing between the discharge gas collecting hood and the outer side of the rotary kiln body; the first sealing mechanism includes a plurality of layered sealing plates and graphite blocks evenly distributed along the circumference of the side port of the discharge gas collecting hood; the graphite blocks are evenly distributed along the circumference of the outer side of the rotary kiln body; the layered sealing plate, the upper end of which is connected to the discharge gas collecting hood, and the lower end of which is overlapped with the upper surface of the graphite block on the outer circumference of the rotary kiln body.

5. The biomass continuous carbonization kiln according to claim 1, wherein: A second sealing mechanism is arranged on both side end surfaces of the heating box body to achieve sealing between the heating box body and the outer side of the rotary kiln body; the second sealing mechanism comprises a plurality of layered sealing plates evenly distributed along the circumference of the side port of the discharge gas collecting hood; the layered sealing plate has an upper end connected to the side surface of the heating box body and a lower end overlapped with the outer side of the rotary kiln body.

6. The biomass continuous carbonization kiln according to claim 4 or 5, characterized in that: The layered sealing plates are fish scales, silicon-aluminum composite plates, and fish scales from top to bottom; one end is fixed to the side of the discharge gas collecting hood or the circumferential inclined plates at both ends of the heating box through a connector, and the other end is overlapped on the rotary kiln body; the outer side is tightened by a steel wire rope, and the entire sealing structure is tightly held by a counterweight hammer.

7. The biomass continuous carbonization kiln according to claim 1, wherein: The lower part of the discharge gas collecting hood wrapped around the kiln head end of the rotary kiln body is the carbonized particle outlet, which is connected to the water-cooling spiral mechanism. The biochar is cooled by the water-cooling spiral mechanism, and the water-cooling spiral machine and the inside of the kiln body also maintain an oxygen-free and slightly negative pressure.

8. The biomass continuous carbonization kiln according to claim 1, wherein: The explosion-proof mechanism is installed on the outside of the kiln tail end of the rotary kiln body, including a pressure relief explosion-proof valve, and an aluminum sheet with a thickness of 2-5 mm is used as a pressure relief point at the kiln tail position.

9. The biomass continuous carbonization kiln according to claim 1, characterized in that: The head end of the inner channel of the rotary kiln body extends out of the head end of the outer channel, and the discharge gas collecting hood is arranged outside the ends of both; the output end of the screw feeding mechanism passes through the side wall of the discharge gas collecting hood and extends into the inner channel of the rotary kiln body.

10. An application of the biomass continuous carbonization kiln as described in claim 1, characterized in that, Proceed as follows: S1. Equipment preparation Start the equipment, and the burner heats the rotary kiln body until the temperature inside the kiln rises to the set temperature. S2. Preheating stage The dried biomass particle material is fed into the inner channel through the feed inlet of the screw feeding mechanism, and the material is sent from the head end of the kiln to the tail end through the baffle plate in the inner channel. During the whole process, the material is preheated to 200 - 300 °C. S3. Carbonization stage The material in the inner channel falls into the outer channel at the tail end of the kiln, and the material is transported from the tail end to the head end again by relying on the baffle plate in the outer channel. The burner in the heating box continuously heats the outer channel to generate biochar and combustible gas. S4. Tail gas treatment After the combustible gas is dust-removed and condensed, a part of it returns to the burner for heating; another part is used for raw material drying or storage or for other purposes. S5. Product collection A water-cooled screw mechanism is installed at the carbonized particle outlet position. The biochar is cooled by the water-cooled screw mechanism. The water-cooled screw mechanism keeps the same anaerobic and slightly negative pressure as the inside of the rotary kiln body. The cooled biomass charcoal is packaged and stored.

Images