Anti-scaling biomass hydrothermal cracking tank and hydrothermal cracking equipment

Abstract

The invention discloses an anti-scaling biomass hydrothermal cracking tank and hydrothermal cracking equipment, and belongs to the technical field of biomass treatment. The problems that in the prior art, scaling of the inner wall of a hydrothermal cracking tank and the outer wall of a heating pipe influences the heating performance of the heating pipe and the production capacity of the hydrothermal cracking tank, and at least one of the inner wall of the hydrothermal cracking tank and the outer wall of the heating pipe cannot be cleaned due to the fact that the top end of the hydrothermal cracking tank is of a closed structure are solved. The hydrothermal cracking tank comprises a reaction cavity, a heating pipe and a steam nozzle, the heating pipe is arranged in the reaction cavity and used for heating biomass in the reaction cavity, and the steam nozzle is arranged at the bottom of the reaction cavity and used for blowing steam into the reaction cavity. The method can be used for biomass hydrothermal cracking.

Description

Technical Field

[0001] This invention belongs to the field of biomass treatment technology, and particularly relates to an anti-scaling biomass hydrothermal pyrolysis tank and hydrothermal pyrolysis equipment. Background Technology

[0002] Biomass pyrolysis typically requires the installation of heating tubes in the pyrolysis equipment to heat the biomass to the temperature required for hydrothermal pyrolysis.

[0003] However, in practical applications, since the temperature of the medium (usually heat transfer oil) that provides heat to the hydrothermal pyrolysis tank can reach 300°C or even 350°C, the inner wall of the hydrothermal pyrolysis tank and the outer wall of the heating tube are in direct contact with biomass. During the hydrothermal pyrolysis process, the material is easily adhered. After prolonged heating, the biomass on the wall will carbonize and scale (e.g., crust and / or gel), which will greatly affect the heat transfer performance of the heating tube and thus affect the production capacity of the hydrothermal pyrolysis tank.

[0004] In the prior art, the top of the hydrothermal pyrolysis tank is usually open, serving as both an inlet for material entry and a means for operators to clean the inner wall of the hydrothermal pyrolysis tank and the outer wall of the heating tubes using mechanical, hydraulic, or pneumatic methods after the tank has been emptied. However, if the top of the hydrothermal pyrolysis tank is a closed structure, descaling cannot be achieved by the above methods. Summary of the Invention

[0005] In view of the above analysis, the present invention aims to provide an anti-scaling biomass hydrothermal pyrolysis tank and hydrothermal pyrolysis equipment to solve at least one of the following problems in the prior art: scaling on the inner wall of the hydrothermal pyrolysis tank and the outer wall of the heating tube affects the heating performance of the heating tube and the production capacity of the hydrothermal pyrolysis tank; and the top of the hydrothermal pyrolysis tank is a closed structure, which makes it impossible to clean the inner wall of the hydrothermal pyrolysis tank and the outer wall of the heating tube.

[0006] The present invention provides a scale-resistant biomass hydrothermal pyrolysis tank, including a reaction chamber, a heating pipe and a steam nozzle. The heating pipe is located in the reaction chamber and is used to heat the biomass in the reaction chamber. The steam nozzle is located at the bottom of the reaction chamber and is used to inject steam into the reaction chamber.

[0007] Furthermore, the steam nozzle has a reaction spray mode and a descaling spray mode;

[0008] When the biomass in the reaction chamber is subjected to hydrothermal pyrolysis, the steam nozzle is in reaction blowing mode and the steam nozzle is opened intermittently.

[0009] After the biomass hydrothermal pyrolysis in the reaction chamber is completed and discharged, the steam nozzle is in descaling mode and the steam nozzle is continuously open.

[0010] Furthermore, the anti-scaling biomass hydrothermal pyrolysis tank also includes a spray water nozzle, which is located at the top of the reaction chamber.

[0011] Furthermore, the spray nozzle has a reaction-off mode and a descaling-on mode;

[0012] When the biomass in the reaction chamber is subjected to hydrothermal pyrolysis, the spray water nozzle is in the reaction shutdown mode and the spray water nozzle is in the closed state.

[0013] After the biomass hydrothermal pyrolysis in the reaction chamber is completed and discharged, the spray water nozzles are in the descaling on mode and the spray water nozzles are in the on state.

[0014] Furthermore, the heating element includes a heating coil and a heating connecting pipe, with two adjacent heating coils connected by the heating connecting pipe.

[0015] Furthermore, there are multiple heating coils, which are arranged along the axial direction of the reaction chamber.

[0016] Furthermore, the heating coils are coaxially arranged with the reaction chamber, and multiple heating coils are evenly distributed.

[0017] Furthermore, there are multiple heating connection pipes, and two adjacent heating coils are connected through multiple heating pipes.

[0018] Furthermore, the number of heating coils is 2 to 4, and the number of connecting heating tubes between two adjacent heating coils is 4 to 6.

[0019] The present invention also provides a hydrothermal pyrolysis device, characterized in that it includes the above-mentioned anti-scaling biomass hydrothermal pyrolysis tank.

[0020] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0021] A) The anti-scaling biomass hydrothermal pyrolysis tank provided by this invention optimizes the biomass hydrothermal pyrolysis reaction process and efficiently solves the scaling problem, achieving the dual functions of "reaction enhancement" and "equipment maintenance," significantly improving the practicality and economy of the equipment. Simultaneously, the switching between the two modes can be completed automatically in conjunction with the reaction process, requiring no manual intervention or opening of the tank top cover, greatly simplifying the operation steps and improving the automation level of equipment operation.

[0022] B) The anti-scaling biomass hydrothermal pyrolysis tank provided by the present invention has a steam nozzle in reaction spray mode. The steam spray can disturb the biomass material in the reaction chamber, break the local temperature and concentration gradient, and make the biomass more fully contacted with heat and steam, avoiding local overheating or incomplete reaction caused by material accumulation, and improving the overall efficiency of hydrothermal pyrolysis.

[0023] C) The anti-scaling biomass hydrothermal pyrolysis tank provided by this invention, after the reaction is completed and the material is discharged, the steam nozzle switches to the "continuously open" descaling spray mode, using high-temperature and high-pressure steam to flush the inner wall of the reaction chamber and the outer wall of the heating tube. Through physical flushing (airflow impact force) and thermal decomposition (high temperature steam softens and removes scale), residual scale is efficiently removed, avoiding scale accumulation that affects subsequent heating efficiency or contaminates the material.

[0024] D) The anti-scaling biomass hydrothermal pyrolysis tank provided by this invention features a spray nozzle that can flexibly switch between reaction-off mode and descaling-on mode according to the process stage, making it perfectly suited for the entire "reaction-discharge-cleaning" process of biomass hydrothermal pyrolysis. Specifically, on the one hand, the reaction-off mode of the spray nozzle provides a stable and undisturbed reaction environment for the biomass hydrothermal pyrolysis reaction, avoiding the impact on reaction efficiency due to accidental opening of the spray nozzle; on the other hand, the nozzle is located at the top of the reaction chamber, and during the descaling-on stage, it directionally flushes the inner wall of the reaction chamber and the outer wall of the heating tube from top to bottom, utilizing the gravity and impact force of the water flow to thoroughly flush the two areas. Compared with traditional bottom water inlet or side flushing, it can act more directly on the scale adhesion surface, thereby significantly improving the scale removal efficiency.

[0025] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0026] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0027] Figure 1 This is a schematic diagram of the anti-scaling biomass hydrothermal pyrolysis tank provided in Embodiment 1 of the present invention;

[0028] Figure 2 This is a schematic diagram of the hydrothermal pyrolysis equipment provided in Embodiment 2 of the present invention;

[0029] Figure 3 This is a schematic diagram of the structure of the disturbance fins in the hydrothermal pyrolysis equipment provided in Embodiment 2 of the present invention;

[0030] Figure 4 This is a schematic diagram of the spiral feeder in the hydrothermal pyrolysis equipment provided in Embodiment 2 of the present invention.

[0031] Figure label:

[0032] 1-Mixing tank; 2-Agitator shaft; 3-Agitator blades; 4-Agitator fins; 401-Central shaft; 402-Blade blade; 5-Screw feeder; 501-Screw housing; 502-Screw shaft; 503-Screw auger blades; 6-Plunger pump; 7-Reaction chamber; 8-Heating coil; 9-Heating connection pipe; 10-Steam nozzle; 11-Spray water nozzle. Detailed Implementation

[0033] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0034] Example 1

[0035] This embodiment provides an anti-scaling biomass hydrothermal pyrolysis tank. See [link to relevant documentation]. Figure 1 It includes a reaction chamber 7, a heating pipe and a steam nozzle 10. The heating pipe is located in the reaction chamber 7 and is used to heat the biomass in the reaction chamber 7. The steam nozzle 10 is located at the bottom of the reaction chamber 7 and is used to blow steam into the reaction chamber 7.

[0036] Specifically, the steam nozzle 10 has a reaction spray mode and a descaling spray mode.

[0037] When the biomass in the reaction chamber 7 is subjected to hydrothermal pyrolysis, the steam nozzle 10 is in the reaction blowing mode and the steam nozzle 10 is opened intermittently, for example, it is opened for 1 to 2 minutes every 8 to 15 minutes.

[0038] After the biomass hydrothermal pyrolysis in the reaction chamber 7 is completed and discharged, the steam nozzle 10 is in the descaling spray mode and the steam nozzle 10 is continuously open.

[0039] Compared with existing technologies, the anti-scaling biomass hydrothermal pyrolysis tank provided in this embodiment can optimize the biomass hydrothermal pyrolysis reaction process and efficiently solve the scaling problem, realizing the dual functions of "reaction enhancement" and "equipment maintenance," significantly improving the practicality and economy of the equipment. At the same time, the switching between the two modes can be completed automatically in conjunction with the reaction process, without manual intervention or opening the tank top cover, greatly simplifying the operation steps and improving the automation level of equipment operation.

[0040] Specifically, the steam nozzle 10 is in the reaction spray mode. The steam spray can disturb the biomass material in the reaction chamber 7, break the local temperature and concentration gradient, and make the biomass more fully contacted with heat and steam. This avoids local overheating or incomplete reaction caused by material accumulation and improves the overall efficiency of hydrothermal pyrolysis.

[0041] After the reaction is completed and the material is discharged, the steam nozzle 10 switches to the "continuously open" descaling spray mode, using high-temperature and high-pressure steam to flush the inner wall of the reaction chamber 7 and the outer wall of the heating tube. Through physical flushing (airflow impact force) and thermal decomposition (high temperature steam softens and removes scale), residual scale is efficiently removed, avoiding scale accumulation that may affect subsequent heating efficiency or contaminate the material.

[0042] In order to flush the inner wall of the reaction chamber 7 and the outer wall of the heating tube from the top of the reaction chamber 7 and improve the cleaning effect, the above-mentioned anti-scaling biomass hydrothermal pyrolysis tank also includes a spray water nozzle 11. The spray water nozzle 11 is located at the top of the reaction chamber 7 and has a reaction off mode and a descaling on mode.

[0043] When the biomass in the reaction chamber 7 is subjected to hydrothermal pyrolysis, the spray water nozzle 11 is in the reaction shutdown mode and the spray water nozzle 11 is in the closed state.

[0044] After the biomass hydrothermal pyrolysis in the reaction chamber 7 is completed and discharged, the spray water nozzle 11 is in the descaling on mode and the spray water nozzle 11 is in the on state.

[0045] In this way, the spray nozzle 11 can flexibly switch between reaction shutdown mode and descaling on mode according to the process stage, making it perfectly suited for the entire "reaction-discharge-cleaning" process of biomass hydrothermal pyrolysis. Specifically, on the one hand, the reaction shutdown mode of the spray nozzle 11 can provide a stable and undisturbed reaction environment for the biomass hydrothermal pyrolysis reaction, avoiding the impact on reaction efficiency due to accidental opening of the spray nozzle 11; on the other hand, the nozzle is located at the top of the reaction chamber 7, and during the descaling on stage, it directionally flushes the inner wall of the reaction chamber 7 and the outer wall of the heating tube from top to bottom. Utilizing the gravity and impact force of the water flow, the two areas are thoroughly flushed. Compared with traditional bottom water inlet or side flushing, it can act more directly on the scale adhesion surface, thereby significantly improving the scale removal efficiency.

[0046] In order to improve the heating uniformity of the biomass in the reaction chamber 7 by the heating tube, the structure of the heating tube specifically includes a heating coil 8 and a heating connecting tube 9. There are multiple heating coils 8, which are arranged along the axial direction of the reaction chamber 7. For example, the heating coils 8 are coaxially arranged with the reaction chamber 7, and the multiple heating coils 8 are evenly arranged.

[0047] Two adjacent heating coils 8 are connected by a heating connecting pipe 9. That is, one end of the heating connecting pipe 9 is connected to one of the heating coils 8, and the other end of the heating connecting pipe 9 is connected to the other heating coil 8. For example, there are multiple heating connecting pipes 9, and two adjacent heating coils 8 are connected by multiple heating pipes.

[0048] In this way, on the one hand, multiple heating coils 8 are evenly arranged along the axial direction of the reaction chamber 7, which is equivalent to dividing the heating area in the reaction chamber 7 into multiple independent but mutually cooperating heating sections, ensuring that biomass at different axial heights is within the target heating temperature range; on the other hand, the heating coils 8 are coaxially arranged with the reaction chamber 7, which means that the distance between the heating coils 8 and the inner wall of the reaction chamber 7 is equal. This concentric structure allows the thermal resistance at each radial point to be consistent and the heat flux density to be uniform when heat is transferred from the heating coils 8 to the center of the reaction chamber 7.

[0049] On the other hand, by setting multiple connecting heating tubes, the heating medium (e.g., heat transfer oil) can be diverted, so that the flow rate and velocity of the heating medium between adjacent heating coils 8 are uniform, avoiding temperature differences between heating coils 8 caused by uneven distribution of heating medium; at the same time, multiple connecting heating tubes are equivalent to establishing multiple thermal bridges between adjacent heating coils 8, which can not only transfer the sensible heat of the heating medium, but also supplement the heat between heating coils 8 through the heat radiation and heat conduction of the heating connecting tubes 9 themselves, further reducing local temperature fluctuations in the reaction chamber 7.

[0050] From the perspective of flow resistance and structure, for example, the number of heating coils 8 is 2 to 4, and the number of connecting heating tubes between two adjacent heating coils 8 is 4 to 6.

[0051] Example 2

[0052] This embodiment provides a hydrothermal pyrolysis device, including the anti-scaling biomass hydrothermal pyrolysis tank provided in Embodiment 1.

[0053] Compared with the prior art, the beneficial effects of the hydrothermal pyrolysis equipment provided in this embodiment are basically the same as those of the anti-scaling biomass hydrothermal pyrolysis tank provided in Embodiment 1, and will not be described in detail here.

[0054] Understandably, in order to achieve biomass conveying and feeding, the aforementioned hydrothermal pyrolysis equipment also includes a mixing tank 1, a screw feeder 5, and a plunger pump 6 connected in sequence. The discharge port of the plunger pump 6 is connected to the inlet of the hydrothermal pyrolysis tank. See [link to relevant documentation]. Figure 2 .

[0055] For example, the biomass is manure and straw. The manure and straw are fed into the mixing tank 1 at the same time. In the mixing tank 1, the straw is further crushed and mixed evenly with the manure before being fed into the screw feeder 5. The screw feeder 5 further mixes and crushes the manure and straw mixture and feeds it into the plunger pump 6. The plunger pump 6 feeds the mixture into the hydrothermal pyrolysis tank for hydrothermal pyrolysis reaction.

[0056] In practical applications, straw is a fibrous, porous solid material with low density, large volume, and lack of fluidity. It also separates into layers with manure, making it impossible for the straw to be squeezed and transported by the plunger pump 6. In order to achieve full mixing and simultaneous feeding of manure and straw, the above-mentioned hydrothermal pyrolysis equipment also includes a stirring shaft 2, stirring blades 3, and agitator fins 4 located in the mixing tank 1. One end of the stirring blades 3 is fixedly connected to the stirring shaft 2, and the other end of the stirring blades 3 is suspended. One end of the agitator fins 4 is fixedly connected to the stirring blades 3, and the other end of the agitator fins 4 is suspended. The stirring blades 3 and the agitator fins 4 form a dendritic structure. In this way, the dendritic structure formed by the stirring blades 3 and the agitation fins 4 increases the agitation of manure and straw within the mixing tank 1, causing the manure and straw to flow back vertically within the mixing tank 1. During repeated contact with the stirring blades 3 and agitation fins 4, the straw fibers are broken down into small particles, further crushing the straw during the mixing process. This ensures thorough mixing of manure and straw, resolving the stratification caused by differences in density and enabling simultaneous feeding of the mixed manure and straw. Furthermore, since manure contains a large number of microorganisms (bacteria, fungi, actinomycetes, etc.), these microorganisms can decompose high-molecular-weight organic matter such as cellulose, hemicellulose, and lignin in straw. For example, cellulose-decomposing bacteria can secrete cellulase to break down cellulose in straw into smaller molecules such as glucose; lignin-decomposing bacteria (such as white-rot fungi) can destroy the structure of lignin through oxidation, making the hard structure of straw loose.

[0057] In order to break down the fibers in the straw in multiple directions, for example, the stirring blade 3 is spiral-shaped, see [reference needed]. Figure 2 The stirring blade 3 has a blade-like edge, and its spiral diameter gradually decreases as it moves away from the stirring shaft 2. This type of stirring blade 3, with its spiral blade-like structure, can break down the straw fibers from multiple directions.

[0058] The spiral diameter of the stirring blade 3 remains unchanged. Along the direction that gradually moves away from the stirring shaft 2, the spiral diameter of the stirring blade 3 gradually decreases, which makes the stirring force of the stirring blade 3 closer to the stirring shaft 2 stronger and the centrifugal force generated larger, while the stirring force of the stirring blade 3 further away from the stirring shaft 2 is weaker and the centrifugal force generated smaller, further promoting the mixing in the vertical direction.

[0059] For the structure of the disturbance fin 4, see [link to documentation]. Figure 3It includes a central shaft 401 and multiple blades 402 disposed on the outer wall of the central shaft 401. The fixed end of the central shaft 401 is fixedly connected to the stirring blades 3, and the suspended end of the central shaft 401 is suspended. Each blade 402 is arranged radially along the central shaft 401, and the multiple blades 402 are evenly arranged circumferentially along the central shaft 401 in a divergent arrangement. The suspended end of the central shaft 401 is a pointed tip. The upper and lower end faces of the blades 402 are both blade structures. In this way, on the one hand, when the straw contacts the tip of the stirring blades 4 along its own axial direction, the tip of the central shaft 401 can break the straw fiber bundles along the axial direction of the straw, thereby reducing the diameter of the straw. On the other hand, when the straw contacts the blade structure of the blades 402 along its own transverse direction, the multi-directionally arranged blades 402 can also break the straw fibers, thereby reducing the length of the straw and achieving thorough crushing of the straw.

[0060] In order to achieve the up-and-down disturbance and backflow of manure and straw, the structure of the mixing blade 3 is such that, along the direction gradually away from the mixing shaft 2 (i.e. from the fixed end of the mixing blade 3 to the suspended end of the mixing blade 3), the lower end face of the mixing blade 3 is set horizontally, and the upper end face of the mixing blade 3 is inclined downward.

[0061] To allow sufficient feeding and backflow space at the top of the mixing tank 1, a gap is provided between the suspended end of the stirring blades 3 and the side wall of the constant-diameter section, allowing the manure and straw in the straight section to flow and mix fully within the gap. Thus, manure and straw are fed into the mixing tank 1 from the top, and under the influence of gravity and feeding pressure, they flow downwards along the gaps between the stirring blades 3 and between the suspended end of the stirring blades 3 and the side wall of the constant-diameter section. When the manure and straw are submerged in the mixing blades 3, under the action of the mixing blades 3, the manure and straw will flow downward along the gap between the suspended end of the mixing blades 3 and the side wall of the constant diameter section. At the same time, the gap between the mixing blades 3 will flow upward, thus forming vertical disturbance and backflow. This allows the manure and straw to come into contact with the same mixing blades 3 and disturbance fins 4 multiple times in the mixing tank 1. Furthermore, it generates mixing in the vertical direction and can also break up the stratification between the manure and straw, achieving full mixing of the manure and straw.

[0062] For details regarding the structure of the screw feeder 5, please refer to [link / reference]. Figure 4 It includes a screw conveyor housing 501 and a screw shaft 502 and a spiral screw conveyor blade 503 disposed within the screw conveyor housing 501. The screw shaft 502 passes through the screw conveyor housing 501 along the axial direction of the screw conveyor housing 501 and is mounted inside the screw conveyor housing 501. The spiral screw conveyor blade 503 is sleeved on the screw shaft 502.

[0063] To further compress and crush the mixture of manure and straw and ensure continuous feeding, and to create pre-pressure at the inlet of the plunger pump 6, specifically, the spiral diameter of the auger blades 503 gradually decreases along the direction from the inlet to the outlet of the auger housing 501. This results in a higher conveying capacity of the auger blades 503 near the inlet of the auger housing 501 and a lower conveying capacity near the outlet, causing the mixture of manure and straw to accumulate at the outlet of the auger housing 501, where it is continuously compressed and crushed. This pre-pressure is then applied to the inlet of the plunger pump 6 to ensure the stability of the plunger pump 6 during material conveying.

[0064] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A fouling-resistant biomass hydrothermal pyrolysis tank, characterized by, The anti-fouling biomass hydrothermal cracking tank comprises a reaction cavity, a heating pipe arranged in the reaction cavity for heating biomass in the reaction cavity, and a steam nozzle arranged at the bottom of the reaction cavity for spraying steam into the reaction cavity.

2. The anti-fouling biomass aquathermolysis tank of claim 1, wherein, The steam nozzle has a reaction spraying mode and a descaling spraying mode. When the biomass in the reaction cavity is subjected to hydrothermal cracking, the steam nozzle is in the reaction spraying mode and is intermittently opened. When the biomass in the reaction cavity is discharged after hydrothermal cracking, the steam nozzle is in the descaling spraying mode and is continuously opened.

3. The anti-fouling biomass aquathermolysis tank of claim 1, wherein, The anti-fouling biomass hydrothermal cracking tank further comprises a water spraying nozzle arranged at the top of the reaction cavity.

4. The anti-fouling biomass aquathermolysis tank of claim 3, wherein, The water spraying nozzle has a reaction closing mode and a descaling opening mode. When the biomass in the reaction cavity is subjected to hydrothermal cracking, the water spraying nozzle is in the reaction closing mode and is closed. When the biomass in the reaction cavity is discharged after hydrothermal cracking, the water spraying nozzle is in the descaling opening mode and is opened.

5. The anti-fouling biomass aquathermolysis tank of claim 1, wherein, The heating pipe comprises a heating coil and a heating connecting pipe.

6. The anti-fouling biomass aquathermolysis tank of claim 5, wherein, The number of the heating coils is multiple, and the multiple heating coils are arranged along the axial direction of the reaction cavity.

7. The anti-fouling biomass aquathermolysis tank of claim 6, wherein, The heating coil is coaxially arranged with the reaction cavity, and the multiple heating coils are uniformly arranged.

8. The anti-fouling biomass aquathermolysis tank of claim 6, wherein, The number of the heating connecting pipes is multiple, and adjacent two heating coils are connected by the multiple heating connecting pipes.

9. The anti-fouling biomass aquathermolysis tank of claim 8, wherein, The number of the heating coils is 2-4, and the number of the connecting heating pipes between adjacent two heating coils is 4-6.

10. A hydrothermal cracking apparatus, characterized by, The anti-fouling biomass hydrothermal cracking tank comprises a reaction cavity, a heating pipe arranged in the reaction cavity for heating biomass in the reaction cavity, and a steam nozzle arranged at the bottom of the reaction cavity for spraying steam into the reaction cavity. The steam nozzle has a reaction spraying mode and a descaling spraying mode. When the biomass in the reaction cavity is subjected to hydrothermal cracking, the steam nozzle is in the reaction spraying mode and is intermittently opened. When the biomass in the reaction cavity is discharged after hydrothermal cracking, the steam nozzle is in the descaling spraying mode and is continuously opened. The anti-fouling biomass hydrothermal cracking tank further comprises a water spraying nozzle arranged at the top of the reaction cavity. The water spraying nozzle has a reaction closing mode and a descaling opening mode. When the biomass in the reaction cavity is subjected to hydrothermal cracking, the water spraying nozzle is in the reaction closing mode and is closed. When the biomass in the reaction cavity is discharged after hydrothermal cracking, the water spraying nozzle is in the descaling opening mode and is opened. The heating pipe comprises a heating coil and a heating connecting pipe. The number of the heating coils is multiple, and the multiple heating coils are arranged along the axial direction of the reaction cavity. The heating coil is coaxially arranged with the reaction cavity, and the multiple heating coils are uniformly arranged. The number of the heating connecting pipes is multiple, and adjacent two heating coils are connected by the multiple heating connecting pipes. The number of the heating coils is 2-4, and the number of the connecting heating pipes between adjacent two heating coils is 4-6. The anti-fouling biomass hydrothermal cracking tank comprises a reaction cavity, a heating pipe arranged in the reaction cavity for heating biomass in the reaction cavity, and a steam nozzle arranged at the bottom of the reaction cavity for spraying steam into the reaction cavity. The steam nozzle has a reaction spraying mode and a descaling spraying mode. When the biomass in the reaction cavity is subjected to hydrothermal cracking, the steam nozzle is in the reaction spraying mode and is intermittently opened. When the biomass in the reaction cavity is discharged after hydrothermal cracking, the steam nozzle is in the descaling spraying mode and is continuously opened. The anti-fouling biomass hydrothermal cracking tank further comprises a water spraying nozzle arranged at the top of the reaction cavity. The water spraying nozzle has a reaction closing mode and a descaling opening mode. When the biomass in the reaction cavity is subjected to hydrothermal cracking, the water spraying nozzle is in the reaction closing mode and is closed. When the biomass in the reaction cavity is discharged after hydrothermal cracking, the water spraying nozzle is in the descaling opening mode and is opened. The heating pipe comprises a heating coil and a heating connecting pipe. The number of the heating coils is multiple, and the multiple heating coils are arranged along the axial direction of the reaction cavity. The heating coil is coaxially arranged with the reaction cavity, and the multiple heating coils are uniformly arranged. The number of the heating connecting pipes is multiple, and adjacent two heating coils are connected by the multiple heating connecting pipes. The number of the heating coils is 2-4, and the number of the connecting heating pipes between adjacent two heating coils is 4-6. The anti-fouling biomass hydrothermal cracking tank comprises a reaction cavity, a heating pipe arranged in the reaction cavity for heating biomass in the reaction cavity, and a steam nozzle arranged at the bottom of the reaction cavity for spraying steam into the reaction cavity. The steam nozzle has a reaction spraying mode and a descaling spraying mode. When the biomass in the reaction cavity is subjected to hydrothermal cracking, the steam nozzle is in the reaction spraying mode and is intermittently opened. When the biomass in the reaction cavity is discharged after hydrothermal cracking, the steam nozzle is in the descaling spraying mode and is continuously opened. The anti-fouling biomass hydrothermal cracking tank further comprises a water spraying nozzle arranged at the top of the reaction cavity. The water spraying nozzle has a reaction closing mode and a descaling opening mode. When the biomass in the reaction cavity is subjected to hydrothermal cracking, the water spraying nozzle is in the reaction closing mode and is closed. When the biomass in the reaction cavity is discharged after hydrothermal cracking, the water spraying nozzle is in the descaling opening mode and is opened. The heating pipe comprises a heating coil and a heating connecting pipe. The number of the heating coils is multiple, and the multiple heating coils are arranged along the axial direction of the reaction cavity. The heating coil is coaxially arranged with the reaction cavity, and the multiple heating coils are uniformly arranged. The number of the heating connecting pipes is multiple, and adjacent two heating coils are connected by the multiple heating connecting pipes. The number of the heating coils is 2-4, and the number of the connecting heating pipes between adjacent two heating coils is 4-6. The anti-fouling biomass hydrothermal cracking tank comprises a reaction cavity, a heating pipe arranged in the reaction cavity for heating biomass in the reaction cavity, and a steam nozzle arranged at the bottom of the reaction cavity for spraying steam into the reaction cavity. The steam nozzle has a reaction spraying mode and a descaling spraying mode. When the biomass in the reaction cavity is subjected to hydrothermal cracking, the steam nozzle is in the reaction spraying mode and is intermittently opened. When the biomass in the reaction cavity is discharged after hydrothermal cracking, the steam nozzle is in the descaling spraying mode and is continuously opened. The anti-fouling biomass hydrothermal cracking tank further comprises a water spraying nozzle arranged at the top of the reaction cavity. The water spraying nozzle has a reaction closing mode and a descaling opening mode. When the biomass in the reaction cavity is subjected to hydrothermal cracking, the water spraying nozzle is in the reaction closing mode and is closed. When the biomass in the reaction cavity is discharged after hydrothermal cracking, the water spraying nozzle is in the descaling opening mode and is opened. The heating pipe comprises a heating coil and a heating connecting pipe. The number of the heating coils is multiple, and the multiple heating coils are arranged along the axial direction of the reaction cavity. The heating coil is coaxially arranged with the reaction cavity, and the multiple heating coils are uniformly arranged. The number of the heating connecting pipes is multiple, and adjacent two heating coils are connected by the multiple heating connecting pipes. The number of the heating coils is 2-4, and the number of the connecting heating pipes between adjacent two heating coils is 4-6. The anti-fouling biomass hydrothermal cracking tank comprises a reaction cavity, a heating pipe arranged in the reaction cavity for heating biomass in the reaction cavity, and a steam nozzle arranged at the bottom of the reaction cavity for spraying steam into the reaction cavity. The steam nozzle has a reaction spraying mode and a descaling spraying mode. When the biomass in the reaction cavity is subjected to hydrothermal cracking, the steam nozzle is in the reaction spraying mode and is intermittently opened. When the biomass in the reaction cavity is discharged after hydrothermal cracking, the steam nozzle is in the descaling spraying mode and is continuously opened. The anti-fouling biomass hydrothermal cracking tank further comprises a water spraying nozzle arranged at the top of the reaction cavity. The water spraying nozzle has a reaction closing mode and a descaling opening mode. When the biomass in the reaction cavity is subjected to hydrothermal cracking, the water spraying nozzle is in the reaction closing mode and is closed. When the biomass in the reaction cavity is discharged after hydrothermal cracking, the water spraying nozzle is in the descaling opening mode and is opened. The heating pipe comprises a heating coil and a heating connecting pipe. The number of the heating coils is multiple, and the multiple heating coils are arranged along the axial direction of the reaction cavity. The heating coil is coaxially arranged with the reaction cavity, and the multiple heating coils are uniformly arranged. The number of the heating connecting pipes is multiple, and adjacent two heating coils are connected by the multiple heating connecting pipes. The number of the heating coils is 2-4, and the number of the connecting heating pipes between adjacent two heating coils is 4-6. The anti-fouling biomass hydrothermal cracking tank comprises a reaction cavity, a heating pipe arranged in the reaction cavity for heating biomass in the reaction cavity, and

Images