A rotary down-draft straw pyrolysis carbon and gas co-production device

Abstract

The present invention discloses a rotary down-draft straw pyrolysis carbon and gas co-production device, which includes a pyrolysis cylinder, a carbon discharging device, and a bracket for supporting the pyrolysis cylinder and the carbon discharging device; the pyrolysis cylinder includes an upper cylinder body, a middle cylinder body, and a lower cylinder body, wherein the middle cylinder body can rotate around the cylinder axis, a pressure feeder is arranged at the top of the middle cylinder body, and stirring rods and air inlet rods are arranged on the inner wall of the middle cylinder body; the carbon discharging device includes a conical rotary cylinder, a spiral carbon conveying plate, and a spiral carbon discharging cylinder; the conical rotary cylinder is arranged at the bottom of the lower cylinder body, the spiral carbon conveying plate is fixedly connected inside the conical rotary cylinder, a water inlet cavity is arranged at the bottom of the conical rotary cylinder, the water inlet cavity is connected to a water tank through a water conveying pipe, and the bottom of the water inlet cavity is communicated with the feeding port of the spiral carbon discharging cylinder; the rotary down-draft straw pyrolysis carbon and gas co-production device in the present invention can solve the problems of slagging, bridging, and arching during the pyrolysis and conveying of materials, and greatly improve the carbon discharging sealing performance and stability of the system.

Description

Technical Field

[0001] The present invention relates to the technical field of pyrolysis equipment, and in particular to a rotary downdraft straw pyrolysis carbon and gas co-production equipment. Background Art

[0002] Currently, the working principle of existing downdraft pyrolysis equipment is as follows: materials enter the pyrolysis reactor through a feeder. When the materials reach a certain height, feeding stops, and pyrolysis starts after ignition. When pyrolysis proceeds to a certain extent, the generated biochar is discharged through a carbon discharging device; the pyrolysis gas is discharged through the exhaust port of the equipment. Patent No. CN105505469A mentions a downdraft fixed bed gasification steam power generation co-production device, including a gasification system and a power generation system. The gasification system includes a feeding device, a primary air inlet, a secondary air inlet, a material pusher, a grate, etc.; the power generation system includes a gas combustion chamber, a pyrolysis gas blower, a cyclone separator, a desulfurization chamber, etc. The materials enter the gasification furnace through the feeding device for pyrolysis gasification, and the material pusher is used to stir the materials during the pyrolysis process. However, the material pusher is fixed on the rotating shaft and has low strength. Patent No. CN110819387A mentions a closed downdraft gasification furnace, including a furnace body, a top bin, a gas-locking discharging valve, a paving reducer, a paving scraper, fuel, a grate, an ash baffle cone, a gas chamber, a furnace plate, a lower end cover of the cone, a gas pipe, a blower, an air inlet pipe, a carbon discharging conveyor, a carbon discharging gas-locking device, and a pressure relief port. After the materials enter the furnace, the paving scraper flattens the materials, and the generated combustible gas enters the gas chamber through the grate with pores on the surface, and finally the gas is sent to the purification equipment through the gas pipe, preventing dust and flue gas from escaping during feeding. However, the carbon discharging sealing device adopted in this invention has poor sealing performance and a risk of material blockage.

[0003] The technical problems existing in the prior art are as follows:

[0004] 1) When biomass raw materials are pyrolyzed, especially corn straw, the materials have poor fluidity and contain alkali metals. When the pyrolysis temperature reaches above 750°C, the alkali metals in the straw will precipitate, causing the raw materials to stick together to form lumpy substances. These lumpy substances are very hard, which will not only affect the pyrolysis process but also damage the equipment. Existing equipment generally installs stirring rods inside the furnace body and continuously stirs during the pyrolysis process. However, due to the high temperature inside the furnace and the heavy materials, the stirring rods and motors are prone to damage.

[0005] 2) Due to the high temperature in the pyrolysis zone and the small particle size of the materials, slagging often occurs, and the lumps formed by slagging are extremely likely to block the discharging device, which not only damages the discharging device but also affects the operation of the equipment.

[0006] 3) Since the pyrolysis process needs to be carried out in an oxygen-free or low-oxygen environment, the sealing effect of the equipment is required to be very high. For down-draft pyrolysis equipment, the raw materials in the pyrolyzer can be divided into a sealing layer, a transition layer, a pyrolysis layer, and a carbonization layer from top to bottom. Since there are still a sealing layer and a transition layer above the pyrolysis layer, special consideration is generally not required for sealing during feeding. However, if no special treatment is carried out during carbon discharge, it will cause the pyrolysis reactor to be directly connected to the external space, allowing external air to pour into the reactor, seriously affecting the pyrolysis reaction process. At the same time, the newly generated biochar has a very high temperature, and spontaneous combustion will occur when it comes into direct contact with air. Existing equipment generally realizes equipment sealing by installing devices such as a rotary air lock and a rotary valve at the carbon discharge port, but such devices generally have a relatively complex structure and poor working effects, and often have problems such as material jamming. In terms of cooling, a condenser is usually sleeved outside the carbon discharge device to cool the biochar, but this method has poor condensation effect, and the condenser is also prone to failure problems after long-term operation. Summary of the Invention

[0007] The purpose of the present invention is to provide a rotary down-draft straw pyrolysis carbon and gas co-production equipment to solve the problems existing in the above-mentioned prior art, so that materials are not prone to slagging and bridging during the pyrolysis and transportation processes, and the carbon discharge sealing and stability of the system are greatly improved.

[0008] To achieve the above purpose, the present invention provides the following solutions:

[0009] The present invention provides a rotary down-draft straw pyrolysis carbon and gas co-production equipment, including a pyrolysis cylinder, a carbon discharge device, and a bracket supporting the pyrolysis cylinder and the carbon discharge device; the pyrolysis cylinder includes an upper section cylinder body, a middle section cylinder body, and a lower section cylinder body arranged in sequence from top to bottom, wherein the middle section cylinder body can rotate around the cylinder axis, a pressure feeder is arranged at the top of the middle section cylinder body, stirring rods and air inlet rods are arranged on the inner wall of the middle section cylinder body, and external air is introduced into the middle section cylinder body through the air inlet rods; the carbon discharge device includes a conical rotary cylinder, a spiral carbon conveyor plate, and a spiral carbon discharge cylinder; the conical rotary cylinder is arranged at the bottom of the lower section cylinder body, the spiral carbon conveyor plate is fixedly connected inside the conical rotary cylinder, a water inlet cavity is arranged at the bottom of the conical rotary cylinder, the water inlet of the water inlet cavity is connected to a water tank through a water delivery pipe, and the bottom of the water inlet cavity is communicated with the feed inlet of the spiral carbon discharge cylinder; an extrusion screw is arranged inside the spiral carbon discharge cylinder, a conical carbon discharge pipe is arranged at the discharge end of the spiral carbon discharge cylinder, and the diameter of the conical carbon discharge pipe gradually becomes smaller along the carbon discharge direction.

[0010] Preferably, a feed inlet is arranged at the top of the upper section cylinder body, an ignition port is arranged on one side of the top of the barrel wall of the lower section cylinder body, and an exhaust pipe is arranged on the other side of the barrel wall of the lower section cylinder body.

[0011] Preferably, a feeding level gauge is provided on the inner wall of the upper section cylinder body, and a discharging level gauge is provided on the inner wall of the middle section cylinder body.

[0012] Preferably, the middle section cylinder body is driven to rotate by a first motor, the first motor is arranged on one side of the bracket, and the power output shaft of the first motor drives the middle section cylinder body to rotate around the axis of the cylinder body through gear transmission.

[0013] Preferably, a pair-roller carbon discharging device is arranged in the lower section cylinder body, and the pair-roller carbon discharging device includes multiple groups of meshing discharging rollers.

[0014] Preferably, the top cylinder body of the conical rotary cylinder is a flared cylinder body with a top diameter larger than the bottom diameter.

[0015] Preferably, the conical rotary cylinder is driven to rotate by a second motor, the second motor is arranged on one side of the bracket, and the power output shaft of the second motor drives the conical rotary cylinder to rotate around the axis of the cylinder body through gear transmission.

[0016] Preferably, the carbon discharging port of the conical carbon discharging pipe faces a carbon collecting box, a water storage tank is arranged at the bottom of the carbon collecting box, and water filtering holes are arranged on the bottom plate of the carbon collecting box.

[0017] Preferably, the cylinder body of the spiral carbon discharging cylinder is obliquely arranged upwards, and the position of the feeding port is lower than the position of the discharging port, and the carbon collecting box is arranged at the bottom of the conical carbon discharging pipe.

[0018] Preferably, a lower water level gauge is provided on the inner wall of the water inlet cavity, and an upper water level gauge is provided on the inner wall of the conical rotary cylinder.

[0019] The present invention has achieved the following beneficial technical effects compared with the prior art:

[0020] 1. The rotary down-draft straw pyrolysis carbon and gas co-production equipment provided by the present invention is a rotary internal heating pyrolysis reactor. The rotary cylinder is internally provided with stirring rods and a pressing device. By the rotation of the cylinder body, the heat transfer, mass transfer and fluidity of the material are enhanced, effectively overcoming problems such as poor material fluidity and slagging caused by uneven heating, and greatly improving the system operation stability and the quality of biochar.

[0021] 2. The rotary down-draft straw pyrolysis carbon and gas co-production equipment provided by the present invention adopts a combined pair-roller carbon discharging device with multiple groups of meshing discharging rollers, forming multiple gaps, which can improve the uniformity of the down-draft air flow, improve the flow field in the pyrolysis zone, and reduce the slagging risk; the spike-tooth discharging rollers can actively crush small pieces of slag, effectively reducing the risk of material blockage.

[0022] 3. The rotary down-draft straw pyrolysis carbon and gas co-production equipment provided by the present invention is provided with a conical rotary multi-stage sealed carbon discharging system. The conical carbon discharging device is internally provided with a spiral carbon conveying plate, which overcomes the bridging and arching phenomena during the discharging process of straw-based biochar and improves the stability of carbon discharging in the system; the spiral extrusion carbon discharging mechanism is combined with water-sealed carbon discharging to ensure the carbon discharging tightness throughout the whole process of starting up and normal operation of the equipment. The combination of conical rotation, spiral extrusion and initial water seal greatly improves the carbon discharging tightness and stability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0024] Figure 1 It is a schematic structural diagram of the rotary down-draft straw pyrolysis carbon and gas co-production equipment in the present invention;

[0025] In the figure: 1 - water tank; 2 - lower water level gauge; 3 - upper water level gauge; 4 - lower section cylinder; 5 - ignition port; 6 - intake rod; 7 - stirring rod; 8 - lower material level gauge; 9 - upper section cylinder; 10 - upper material level gauge; 11 - feed inlet; 12 - pressure feeder; 13 - middle section cylinder; 14 - exhaust pipe; 15 - pair-roller carbon discharger; 16 - spiral carbon conveying plate; 17 - conical rotary cylinder; 18 - conical carbon discharging pipe; 19 - carbon collecting box; 20 - spiral carbon discharging cylinder; 21 - water delivery pipe; 22 - support. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0027] The purpose of the present invention is to provide a rotary down-draft straw pyrolysis carbon and gas co-production equipment to solve the problems existing in the prior art.

[0028] In order to make the above objects, features and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the drawings and specific embodiments.

[0029] The rotary down-draft straw pyrolysis carbon and gas co-production equipment in this embodiment, such as Figure 1As shown in the figure, it includes a pyrolysis cylinder, a carbon discharging device, and a bracket for supporting the pyrolysis cylinder and the carbon discharging device; the pyrolysis cylinder includes an upper cylinder body 9, a middle cylinder body 13, and a lower cylinder body 4 arranged in sequence from top to bottom. The upper cylinder body 9, the middle cylinder body 13, and the lower cylinder body 4 are all supported on the bracket by support rods. Among them, a feed inlet 11 is arranged at the top of the upper cylinder body 9. The middle cylinder body 13 can rotate around the cylinder axis. A pressure feeder 12 is arranged at the top of the middle cylinder body 13. Stirring rods 7 and air inlet rods 6 are arranged on the inner wall of the middle cylinder body 13. External air is introduced into the middle cylinder body 13 through the air inlet rods 6. A pair-roller carbon discharger 15 is arranged in the lower cylinder body 4. The pair-roller carbon discharger 15 is composed of multiple groups of meshing discharge rollers. An ignition port 5 is arranged on one side of the top of the cylinder wall of the lower cylinder body 4, and an exhaust pipe 14 is arranged on the other side of the cylinder wall of the lower cylinder body 4; the carbon discharging device includes a conical rotary cylinder 17, a spiral carbon conveying plate 16, and a spiral carbon discharging cylinder 20; the conical rotary cylinder 17 is arranged at the bottom of the lower cylinder body 4. The spiral carbon conveying plate 16 is fixedly connected inside the conical rotary cylinder 17. A water inlet cavity is arranged at the bottom of the conical rotary cylinder 17. The water inlet of the water inlet cavity is connected to a water tank 1 through a water pipe 21. The bottom of the water inlet cavity is communicated with the feed inlet of the spiral carbon discharging cylinder 20; an extrusion screw is arranged inside the spiral carbon discharging cylinder 20. A conical carbon discharging pipe 18 is arranged at the discharging end of the spiral carbon discharging cylinder 20. The diameter of the conical carbon discharging pipe 18 gradually decreases along the carbon discharging direction.

[0030] In this specific embodiment, a feeding level gauge 10 is arranged on the inner wall of the upper cylinder body 9, and a discharging level gauge 8 is arranged on the inner wall of the middle cylinder body 13; a lower water level gauge 2 is arranged on the inner wall of the water inlet cavity, and an upper water level gauge 3 is arranged on the inner wall of the conical rotary cylinder 17.

[0031] In this specific embodiment, the middle cylinder body 13 is driven to rotate by a first motor. The first motor is arranged on one side of the bracket. The power output shaft of the first motor drives the middle cylinder body 13 to rotate around the axis of the cylinder through gear transmission.

[0032] In this specific embodiment, the top cylinder body of the conical rotary cylinder 17 is a flared cylinder body with a top diameter larger than the bottom diameter.

[0033] In this specific embodiment, the conical rotary cylinder 17 is driven to rotate by a second motor. The second motor is arranged on one side of the bracket. The power output shaft of the second motor drives the conical rotary cylinder 17 to rotate around the axis of the cylinder through gear transmission.

[0034] In this specific embodiment, the nozzle of the conical carbon discharging pipe 18 faces a carbon collecting box 19. A water storage tank is arranged at the bottom of the carbon collecting box 19. Filter water holes are arranged on the bottom plate of the carbon collecting box 19; the cylinder body of the spiral carbon discharging cylinder 20 is arranged obliquely upward, and the position of the feed inlet is lower than the position of the discharging outlet. The carbon collecting box 19 is arranged at the bottom of the conical carbon discharging pipe 18.

[0035] In the rotary down-draft straw pyrolysis carbon and gas co-production equipment of the present invention, during operation, the water in the water tank 1 is first transported to the reactor through the water delivery pipe 21. When the water level reaches the upper water level gauge 3, the water injection stops. At this time, the reactor is in a water seal state. When the water level is lower than the lower water level gauge 2, the water injection continues. The material enters the reactor through the feed inlet 11. The material accumulates in the cylinder. When the material level reaches the upper material level gauge 10, the feeding stops. The material surface is flattened under the action of the pressure feeder 12, and the material is compacted. After the feeding is completed, ignition is carried out through the ignition port 5, and the material starts to pyrolyze. During the pyrolysis process, the stirring rod 7 plays a role in stirring the material to prevent the material from slagging. The air inlet rod 6 is responsible for providing oxygen during the pyrolysis process to improve the gas production rate of the equipment. When the material level is lower than the lower material level gauge 8, the feeding device starts to feed continuously. The biochar generated by pyrolysis is broken by the roller carbon discharging device 15 and falls into the conical rotary cylinder 17. The spiral carbon conveying plate 16 rotates together with the conical rotary cylinder 17 to transport the biochar in the cylinder downward. When the biochar reaches the bottom, it is transported outward under the action of the spiral carbon discharging cylinder 20. Under the action of the conical carbon discharging pipe 18, the water-containing biochar is extruded and discharged. Through extrusion, part of the water can be removed, and the carbon discharging port can also be blocked to enhance the sealing performance. The conical carbon discharging pipe 18 is connected to the equipment through a flange. For the biochar produced from different materials, the carbon discharging pipe with the corresponding taper can be replaced. The biochar falls into the carbon collection box 19 through the conical carbon discharging pipe 18. The bottom of the carbon collection box 19 is provided with a bottom plate with round holes and a water storage tank for separating and collecting the water contained in the biochar.

[0036] The present invention uses specific examples to elaborate on the principle and implementation mode of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation mode and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A rotary down-draft straw pyrolysis carbon and gas co-production device, characterized in that: It includes a pyrolysis cylinder, a carbon discharging device, and a bracket for supporting the pyrolysis cylinder and the carbon discharging device; the pyrolysis cylinder includes an upper section cylinder body, a middle section cylinder body, and a lower section cylinder body arranged in sequence from top to bottom, wherein the middle section cylinder body can rotate around the cylinder axis, a pressure feeder is arranged at the top of the middle section cylinder body, stirring rods and air inlet rods are arranged on the inner wall of the middle section cylinder body, and external air is introduced into the middle section cylinder body through the air inlet rods; the carbon discharging device includes a conical rotary cylinder, a spiral carbon conveying plate, and a spiral carbon discharging cylinder; the conical rotary cylinder is arranged at the bottom of the lower section cylinder body, the spiral carbon conveying plate is fixedly connected inside the conical rotary cylinder, a water inlet cavity is arranged at the bottom of the conical rotary cylinder, the water inlet of the water inlet cavity is connected to a water tank through a water conveying pipe, and the bottom of the water inlet cavity is communicated with the feed inlet of the spiral carbon discharging cylinder; an extrusion screw is arranged inside the spiral carbon discharging cylinder, a conical carbon discharging pipe is arranged at the discharging end of the spiral carbon discharging cylinder, and the diameter of the conical carbon discharging pipe gradually becomes smaller along the carbon discharging direction; A feed inlet is arranged at the top of the upper section cylinder body, an ignition port is arranged on one side of the top of the barrel wall of the lower section cylinder body, and an exhaust pipe is arranged on the other side of the barrel wall of the lower section cylinder body; A material upper level gauge is arranged on the inner wall of the upper section cylinder body, and a material lower level gauge is arranged on the inner wall of the middle section cylinder body.

2. The rotary down-draft straw pyrolysis carbon and gas co-production equipment according to claim 1, characterized in that: The middle section cylinder body is driven to rotate by a first motor, the first motor is arranged on one side of the bracket, and the power output shaft of the first motor drives the middle section cylinder body to rotate around the axis of the cylinder body through gear transmission.

3. The rotary down-draft straw pyrolysis carbon and gas co-production equipment according to claim 1, characterized in that: A pair-roller carbon discharging device is arranged inside the lower section cylinder body, and the pair-roller carbon discharging device includes multiple groups of meshing discharging rollers.

4. The rotary down-draft straw pyrolysis carbon and gas co-production equipment according to claim 1, characterized in that: The top cylinder body of the conical rotary cylinder is a flared cylinder body with a top diameter larger than the bottom diameter.

5. The rotating down-draft straw pyrolysis carbon and gas co-production equipment according to claim 1, characterized in that: The conical rotary cylinder is driven to rotate by a second motor, the second motor is arranged on one side of the bracket, and the power output shaft of the second motor drives the conical rotary cylinder to rotate around the axis of the cylinder body through gear transmission.

6. The rotating down-draft straw pyrolysis carbon and gas co-production equipment according to claim 1, wherein: The carbon discharging port of the conical carbon discharging pipe faces a carbon collecting box, a water storage tank is arranged at the bottom of the carbon collecting box, and water filtering holes are arranged on the bottom plate of the carbon collecting box.

7. The rotary down-draft straw pyrolysis carbon and gas co-production equipment according to claim 6, characterized in that: The cylinder body of the spiral carbon discharging cylinder is arranged obliquely upward, and the position of the feed inlet of the spiral carbon discharging cylinder is lower than the position of the discharging outlet, and the carbon collecting box is arranged at the bottom of the conical carbon discharging pipe.

8. The rotary down-draft straw pyrolysis carbon and gas co-production equipment according to claim 1, characterized in that: A lower water level gauge is arranged on the inner wall of the water inlet cavity, and an upper water level gauge is arranged on the inner wall of the conical rotary cylinder.

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