Biomass and log synergistic carbonization process based on multi-energy coupling and intelligent control

Abstract

The invention discloses a biomass and log synergistic carbonization process based on multi-energy coupling and intelligent control, relates to the technical field of biomass carbonization energy utilization, and couples and integrates continuous carbonization of a biomass material prepared from agriculture and forestry solid waste and batch dry distillation carbonization of a log material. Continuous carbonization of a biomass material prepared from agriculture and forestry solid waste and batch destructive distillation carbonization of a log material are coupled and integrated, so that two different carbonization processes can realize heat energy coupling circulation, wood vinegar and tar are not generated in the carbonization process, flue gas is completely converted into heat energy through high-temperature combustion, the heat energy self-circulation utilization rate reaches 82%, and the energy consumption is low. And the comprehensive energy consumption is reduced by 76%. Moreover, intelligent control and accurate temperature control are realized, wood vinegar and tar are not generated in the carbonization process, and the device is environment-friendly and energy-saving.

Description

Technical Field

[0001] This invention relates to the field of biomass carbonization energy utilization technology, specifically to a biomass and log co-carbonization process based on multi-energy coupling and intelligent control. Background Technology

[0002] Biomass carbonization technology is a type of biomass thermochemical conversion technology. It involves heating chopped or shaped biomass raw materials in a limited or oxygen-free environment to cause internal molecular decomposition, resulting in biochar, wood vinegar, wood tar, and non-condensable gaseous products. Biochar can be used as a high-quality energy source, soil conditioner, reducing agent, slow-release fertilizer carrier, and carbon dioxide sequestration agent, and is widely applied in carbon sequestration and emission reduction, water purification, heavy metal adsorption, and soil improvement.

[0003] Current biochar preparation methods all involve pyrolyzing and carbonizing biomass under anaerobic high-temperature conditions. However, the high-temperature pyrolysis process of biomass is complex, involving both endothermic and exothermic phenomena, and the use of external heating makes it difficult to stabilize and control the pyrolysis temperature, which is prone to rise. This not only reduces the biochar yield but also alters the carbon structure of the biochar produced by the high-temperature environment. The bonds between carbon atoms are very stable and difficult to combine with functional groups, resulting in biochar that retains only a strong adsorption effect but has almost completely lost its surface and biological activity, becoming what is commonly known as dead biochar. When used as a soil conditioner, this type of biochar can adsorb a large amount of nutrients from the soil, but due to the stable structure between carbon atoms, it is difficult to be decomposed and utilized as a carbon source for microorganisms. Moreover, existing biochar processing equipment is mostly an integrated design, resulting in poor biomass flowability and mutual interference between the drying and pyrolysis processes, which not only wastes energy but also affects the staged temperature control of biomass during carbonization. Another prominent issue is that most existing carbonization equipment has a simple structure, only capable of carbonizing biomass pellets, resulting in significant heat loss during the carbonization process. In contrast, log charcoal, a high-density solid wood charcoal, is a pure natural charcoal made from whole pieces of wood in an oxygen-deficient environment. It has high density, long burning time, high calorific value, low ash content, and produces a unique wood aroma when burned. Log charcoal (especially fruitwood charcoal) provides stable and sustained high temperatures and imparts a unique smoky flavor to food, making it popular in professional barbecues and high-end restaurants. Research reveals that there are currently no precedents for the efficient integrated processing of agricultural and forestry solid waste carbonization and log carbonization. Summary of the Invention

[0004] To address the shortcomings of the aforementioned technologies, this invention provides a biomass and log co-carbonization process based on multi-energy coupling and intelligent control.

[0005] The technical solution adopted by the present invention to achieve the above-mentioned technical effects is as follows:

[0006] The biomass and log co-carbonization process based on multi-energy coupling and intelligent control integrates the continuous carbonization of biomass materials made from agricultural and forestry solid waste with the batch dry distillation carbonization of log materials. The process steps include:

[0007] S1. Initial preheating: using natural gas to carbonize the biomass continuous carbonization reactor and batch dry distillation of logs.

[0008] The reactor is preheated until its internal temperature reaches 400°C;

[0009] S2, primary thermal coupling, after preheating to 400℃, is continuously carbonized into biomass via a conveying system.

[0010] The reactor is continuously fed, causing the biomass to rapidly release high-temperature pyrolysis gas at 400℃ into the thermal combustion chamber of the biomass continuous carbonization reactor and the log batch dry distillation carbonization reactor, where it is burned. The high-temperature pyrolysis gas from the combustion undergoes primary heat exchange with the log batch dry distillation carbonization reactor, further preheating the reactor until the internal temperature of the biomass continuous carbonization reactor reaches 500-650℃, at which point the biomass carbonization is completed and the cooled output is completed.

[0011] S3, continuous biomass carbonization cycle operation, continuously releasing high levels of biomass carbonization energy during the process.

[0012] The self-sustaining combustion of the thermally pyrolyzed gas provides thermal energy for the continuous biomass carbonization reactor and the batch dry distillation carbonization reactor for logs.

[0013] S4. After the temperature inside the log batch dry distillation carbonization reactor is raised to above 700°C, the logs are then conveyed through the conveying system.

[0014] Feed one batch of logs into the dry distillation and carbonization reactor until the logs fill the interior and then seal it.

[0015] S5, secondary thermal coupling, enables the logs to rapidly release a large amount of high-temperature pyrolysis gas into the thermal combustion chamber under high-temperature and oxygen-deficient conditions of 700℃ and burn it until the temperature in the thermal combustion chamber rises to about 800℃, thus realizing the dry distillation and calcination of the logs.

[0016] S6. After the log material in the previous batch of log carbonization reactor in step S4 is calcined for 60 minutes, it is fed to another batch of log carbonization reactor through the conveying system until the log material fills the interior and then it is sealed.

[0017] S7. After the log material in the dry distillation and carbonization reactor of the next batch of logs in step S6 is calcined for 60 minutes, the charcoal obtained by calcining the log material in the dry distillation and carbonization reactor of the previous batch of logs after 120 minutes is sent to the multi-stage cooling system. Then, step S4 continues, so that the dry distillation and carbonization reactor of the previous batch of logs and the dry distillation and carbonization reactor of the next batch of logs work alternately.

[0018] S8, three-stage thermal energy coupling, exchanges the 700-800℃ high-temperature flue gas discharged after the pyrolysis gas is fully combusted in the thermal energy combustion chamber with biomass materials, log materials, or steam boiler exhaust gas for heat exchange.

[0019] Preferably, in the above-mentioned biomass and log co-carbonization process based on multi-energy coupling and intelligent control, the log batch dry distillation carbonization reactor maintains a slight negative pressure of -50 to -100 Pa.

[0020] Preferably, in the above-mentioned biomass and log co-carbonization process based on multi-energy coupling and intelligent control, the thermal combustion chamber is connected to an online pyrolysis gas component analyzer equipped with a GC-MS system to monitor the concentration of pyrolysis gas in the thermal combustion chamber in real time. When the concentration of pyrolysis gas is greater than 500 ppm, the self-sustaining combustion of pyrolysis gas is automatically started, and the combustion of natural gas stops.

[0021] Preferably, in the above-mentioned biomass and log co-carbonization process based on multi-energy coupling and intelligent control, the multi-stage cooling system includes a first-stage rapid cooling and a second-stage slow cooling. The first-stage rapid cooling uses low-temperature nitrogen injection to quickly cool the high-temperature log charcoal to 300°C. The second-stage slow cooling uses a circulating water-cooled wall to gradually cool the log charcoal, which has been rapidly cooled to 300°C, to 60°C.

[0022] Preferably, in the above-mentioned biomass and log co-carbonization process based on multi-energy coupling and intelligent control, the purity of the low-temperature nitrogen gas used in the first-stage rapid cooling is ≥99.5%, and the water temperature of the circulating water-cooled wall used in the second-stage slow cooling is 40℃.

[0023] Preferably, in the above-mentioned biomass and log co-carbonization process based on multi-energy coupling and intelligent control, both the biomass continuous carbonization reactor and the log batch dry distillation carbonization reactor are made of long straight metal boxes, arranged horizontally, and the metal boxes are made of 253MA high-temperature resistant steel.

[0024] Preferably, in the above-mentioned biomass and log co-carbonization process based on multi-energy coupling and intelligent control, the biomass continuous carbonization reactor uses a rotary chain plate to drive the material movement, and the feed inlet and discharge outlet are located at the same end of the box, wherein the feed inlet is located at the top of the box and the discharge outlet is located at the bottom of the box. The log batch dry distillation carbonization reactor uses a hydraulic propulsion system to realize automatic feeding and discharging, wherein the feed inlet is located at the front end of the box and the discharge outlet is located at the rear end of the box.

[0025] Preferably, in the above-mentioned biomass and log co-carbonization process based on multi-energy coupling and intelligent control, the length-to-diameter ratio of the biomass continuous carbonization reactor and the log batch dry distillation carbonization reactor is 18:1, and the inner wall is provided with a silicon carbide wear-resistant layer.

[0026] The beneficial effects of this invention are as follows: By coupling and integrating the continuous carbonization of biomass materials made from agricultural and forestry solid waste with the batch dry distillation carbonization of log materials, this invention enables two different carbonization processes to achieve thermal energy coupling and circulation. No wood acetic acid or tar is produced during the carbonization process, and the flue gas is completely converted into heat energy through high-temperature combustion, achieving a heat energy self-circulation utilization rate of 82% and reducing overall energy consumption by 76%. Moreover, it achieves intelligent control and precise temperature control. Detailed Implementation

[0027] To provide a further understanding of the present invention, the invention will be further described below with reference to specific embodiments:

[0028] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or a connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0029] Embodiments of this invention propose a biomass and log co-carbonization process based on multi-energy coupling and intelligent control, which integrates the continuous carbonization of biomass materials made from agricultural and forestry solid waste with the batch dry distillation carbonization of log materials. The process steps include:

[0030] S1. Initial preheating: using natural gas to carbonize the biomass continuous carbonization reactor and batch dry distillation of logs.

[0031] The reactor is preheated until its internal temperature reaches 400°C;

[0032] S2, primary thermal coupling, after preheating to 400℃, is continuously carbonized into biomass via a conveying system.

[0033] The reactor is continuously fed, causing the biomass to rapidly release high-temperature pyrolysis gas at 400℃ into the thermal combustion chamber of the biomass continuous carbonization reactor and the log batch dry distillation carbonization reactor, where it is burned. The high-temperature pyrolysis gas from the combustion undergoes primary heat exchange with the log batch dry distillation carbonization reactor, further preheating the reactor until the internal temperature of the biomass continuous carbonization reactor reaches 500-650℃, at which point the biomass carbonization is completed and the cooled output is completed.

[0034] S3, continuous biomass carbonization cycle operation, continuously releasing high levels of biomass carbonization energy during the process.

[0035] The self-sustaining combustion of the thermally pyrolyzed gas provides thermal energy for the continuous biomass carbonization reactor and the batch dry distillation carbonization reactor for logs.

[0036] S4. After the temperature inside the log batch dry distillation carbonization reactor is raised to above 700°C, the logs are then conveyed through the conveying system.

[0037] Feed one batch of logs into the dry distillation and carbonization reactor until the logs fill the interior and then seal it.

[0038] S5, secondary thermal coupling, enables the logs to rapidly release a large amount of high-temperature pyrolysis gas into the thermal combustion chamber under high-temperature and oxygen-deficient conditions of 700℃ and burn it until the temperature in the thermal combustion chamber rises to about 800℃, thus realizing the dry distillation and calcination of the logs.

[0039] S6. After the log material in the previous batch of log carbonization reactor in step S4 is calcined for 60 minutes, it is fed to another batch of log carbonization reactor through the conveying system until the log material fills the interior and then it is sealed.

[0040] S7. After the log material in the dry distillation and carbonization reactor of the next batch of logs in step S6 is calcined for 60 minutes, the charcoal obtained by calcining the log material in the dry distillation and carbonization reactor of the previous batch of logs after 120 minutes is sent to the multi-stage cooling system. Then, step S4 continues, so that the dry distillation and carbonization reactor of the previous batch of logs and the dry distillation and carbonization reactor of the next batch of logs work alternately.

[0041] S8, three-stage thermal energy coupling, exchanges the 700-800℃ high-temperature flue gas discharged after the pyrolysis gas is fully combusted in the thermal energy combustion chamber with biomass materials, log materials, or steam boiler exhaust gas for heat exchange.

[0042] Furthermore, in a preferred embodiment of the present invention, a slight negative pressure of -50 to -100 Pa is maintained inside the log batch dry distillation carbonization reactor. The thermal combustion chamber is connected to an online pyrolysis gas component analyzer equipped with a GC-MS coupled system to monitor the concentration of pyrolysis gas inside the thermal combustion chamber in real time. When the concentration of pyrolysis gas exceeds 500 ppm, the self-sustaining combustion of the pyrolysis gas is automatically initiated, and the combustion of natural gas ceases.

[0043] Furthermore, in a preferred embodiment of the present invention, the multi-stage cooling system includes a primary rapid cooling stage and a secondary slow cooling stage. The primary rapid cooling stage employs low-temperature nitrogen injection to rapidly cool the high-temperature charcoal to 300°C. The secondary slow cooling stage employs a circulating water-cooled wall to gradually cool the charcoal from 300°C to 60°C. As a preferred embodiment, the purity of the low-temperature nitrogen used in the primary rapid cooling stage is ≥99.5%, and the water temperature of the circulating water-cooled wall used in the secondary slow cooling stage is 40°C.

[0044] Furthermore, in a preferred embodiment of the present invention, both the biomass continuous carbonization reactor and the log batch carbonization reactor are constructed from long, straight metal boxes arranged horizontally. The metal boxes are made of 253MA high-temperature resistant steel. Specifically, the biomass continuous carbonization reactor uses a rotary chain plate to move the material. The inlet and outlet are located at the same end of the box, with the inlet at the top and the outlet at the bottom. The log batch carbonization reactor uses a hydraulic propulsion system for automatic feeding and discharging. The inlet is located at the front end of the box, and the outlet at the rear end. The hydraulic propulsion system is driven by a servo motor, with a push rod stroke accuracy of ±0.5mm and a pushing speed adjustable from 0.2-0.5m / min.

[0045] Furthermore, in a preferred embodiment of the present invention, the length-to-diameter ratio of both the biomass continuous carbonization reactor and the log batch dry distillation carbonization reactor is 18:1, and the inner wall is provided with a silicon carbide wear-resistant layer.

[0046] Multiple experimental data show that this invention can reduce natural gas consumption to 0.03 m³ / T of char. The 700-800℃ high-temperature flue gas discharged after complete combustion in the thermal combustion chamber exchanges heat with the boiler's tail gas, and the waste heat from this tail gas can enable the steam boiler to produce 10T / h of steam (pressure 0.8MPa, 150℃), or be used for pre-drying of biomass and log materials. This invention does not produce wood acetic acid or tar during the carbonization process, making it environmentally friendly and energy-saving.

[0047] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection claimed by the appended claims and their equivalents is defined.

Claims

1. A biomass and log co-carbonization process based on multi-energy coupling and intelligent control, characterized in that, The continuous carbonization of biomass materials made from agricultural and forestry solid waste is coupled and integrated with the batch dry distillation carbonization of log materials. The process steps include: S1. Initial preheating: The biomass continuous carbonization reactor and the log batch dry distillation carbonization reactor are preheated with natural gas until their internal temperature reaches 400°C. S2, First-stage thermal coupling: After preheating to 400℃, the biomass is continuously fed to the continuous biomass carbonization reactor through the conveying system, so that the biomass can quickly release high-temperature pyrolysis gas at 400℃ into the thermal combustion chamber of the continuous biomass carbonization reactor and the log batch dry distillation carbonization reactor and burn. The high-temperature pyrolysis gas from the combustion has a first-stage heat exchange with the log batch dry distillation carbonization reactor, which further preheats the log batch dry distillation carbonization reactor until the internal temperature of the continuous biomass carbonization reactor rises to 500-650℃, at which point the biomass carbonization is completed and the cooled output is output. S3. The biomass continuous carbonization cycle works repeatedly. The high-temperature pyrolysis gas continuously released during the biomass carbonization process is self-sustainingly combusted to provide thermal energy for the biomass continuous carbonization reactor and the log batch dry distillation carbonization reactor. S4. After the temperature inside the log batch dry distillation carbonization reactor is raised to above 700°C, the log batch dry distillation carbonization reactor is fed into one of the log batches through the conveying system until the logs fill the interior and then it is sealed. S5, secondary thermal coupling, enables the logs to rapidly release a large amount of high-temperature pyrolysis gas into the thermal combustion chamber under high-temperature and oxygen-deficient conditions of 700℃ and burn it until the temperature in the thermal combustion chamber rises to about 800℃, thus realizing the dry distillation and calcination of the logs. S6. After the log material in the previous batch of log carbonization reactor in step S4 is calcined for 60 minutes, it is fed to another batch of log carbonization reactor through the conveying system until the log material fills the interior and then it is sealed. S7. After the log material in the dry distillation and carbonization reactor of the next batch of logs in step S6 is calcined for 60 minutes, the charcoal obtained by calcining the log material in the dry distillation and carbonization reactor of the previous batch of logs after 120 minutes is sent to the multi-stage cooling system. Then, step S4 continues, so that the dry distillation and carbonization reactor of the previous batch of logs and the dry distillation and carbonization reactor of the next batch of logs work alternately. S8, three-stage thermal energy coupling, exchanges the 700-800℃ high-temperature flue gas discharged after the pyrolysis gas is fully combusted in the thermal energy combustion chamber with biomass materials, log materials, or steam boiler exhaust gas for heat exchange.

2. The biomass and log co-carbonization process based on multi-energy coupling and intelligent control according to claim 1, characterized in that, The log batch dry distillation carbonization reactor maintains a slight negative pressure of -50 to -100 Pa.

3. The biomass and log co-carbonization process based on multi-energy coupling and intelligent control according to claim 1, characterized in that, The thermal combustion chamber is connected to an online pyrolysis gas component analyzer equipped with a GC-MS system to monitor the concentration of pyrolysis gas in the thermal combustion chamber in real time. When the concentration of pyrolysis gas is greater than 500 ppm, the self-sustaining combustion of pyrolysis gas is automatically started, and the combustion of natural gas stops.

4. The biomass and log co-carbonization process based on multi-energy coupling and intelligent control according to claim 1, characterized in that, The multi-stage cooling system includes a first-stage rapid cooling and a second-stage slow cooling. The first-stage rapid cooling uses low-temperature nitrogen injection to quickly cool the high-temperature raw charcoal to 300°C. The second-stage slow cooling uses a circulating water-cooled wall to gradually cool the raw charcoal, which has been rapidly cooled to 300°C, to 60°C.

5. The biomass and log co-carbonization process based on multi-energy coupling and intelligent control according to claim 4, characterized in that, The purity of the low-temperature nitrogen gas used in the first-stage rapid cooling is ≥99.5%, and the water temperature of the circulating water-cooled wall used in the second-stage slow cooling is 40℃.

6. The biomass and log co-carbonization process based on multi-energy coupling and intelligent control according to claim 1, characterized in that, Both the biomass continuous carbonization reactor and the log batch dry distillation carbonization reactor are made of long, straight metal boxes arranged horizontally, and the metal boxes are made of 253MA high-temperature resistant steel.

7. The biomass and log co-carbonization process based on multi-energy coupling and intelligent control according to claim 6, characterized in that, The biomass continuous carbonization reactor uses a rotary chain plate to move the material. The feed inlet and discharge outlet are located at the same end of the box, with the feed inlet at the top of the box and the discharge outlet at the bottom of the box. The log batch dry distillation carbonization reactor uses a hydraulic propulsion system to achieve automatic feeding and discharging, with the feed inlet at the front end of the box and the discharge outlet at the rear end of the box.

8. The biomass and log co-carbonization process based on multi-energy coupling and intelligent control according to claim 6, characterized in that, The length-to-diameter ratio of both the biomass continuous carbonization reactor and the log batch dry distillation carbonization reactor is 18:1, and the inner wall is provided with a silicon carbide wear-resistant layer.