Biomass carbonization system and method

Abstract

The invention relates to the field of biomass recycling, in particular to a biomass carbonization system which comprises a fluidized bed dryer, a carbonization furnace and a combustor. The method comprises the following steps: (1) in the fluidized bed dryer, drying a biomass raw material by using a gas drying medium to obtain a dried material; (2) in a carbonization furnace, pyrolyzing and carbonizing the dried material by using first flue gas generated by a combustor to obtain charcoal and pyrolysis gas, and discharging the first flue gas after heat release as second flue gas; (3) in the combustor, first flue gas is obtained after the pyrolysis gas is combusted; the gas drying medium is second flue gas and / or third flue gas obtained after heat exchange between air and biochar at high temperature. Through gradient utilization of hot flue gas and cyclic utilization of pyrolysis byproducts, the energy utilization rate of the system is greatly improved, the fluidized bed dryer can treat different kinds of large-batch biomass, and the biomass carbonization capacity is greatly improved.

Description

Technical Field

[0001] The present invention relates to the field of biomass resource utilization, and in particular to a system and method for biomass carbonization. Background Art

[0002] Biomass refers to various organic substances produced through photosynthesis. It is a renewable resource, abundant in my country. Biomass can be dried and carbonized to produce biochar. It can also be gasified through hydrogen-enriched reforming to produce synthesis gas, which can then be synthesized into methanol or synthetic ammonia. This enables resource recycling, replaces traditional energy sources such as coal and oil, and reduces pollution and carbon emissions at the source. In agriculture, biochar can increase soil fertility and improve soil structure. In environmental remediation, it can be used to treat water and air pollution. Therefore, biomass carbonization technology has enormous development potential.

[0003] CN 221071403 U discloses a straw biomass carbonization production system. This method utilizes a negative pressure oxygen-free carbonization furnace as the main component for a complete straw carbonization process from farmland to factory. The negative pressure oxygen-free carbonization furnace is equipped with several layers of sealed hoods and an in-furnace conveying mechanism, which improves the utilization of the space within the pyrolysis furnace. After straw is recovered, it is fed into the negative pressure oxygen-free carbonization furnace for carbonization. After carbonization, the biochar and byproducts are collected through condensation. However, the negative pressure oxygen-free carbonization furnace used in this carbonization system is complex in design and relatively expensive. Furthermore, the biomass is not dried before carbonization, and moisture in the biomass affects the carbonization rate.

[0004] CN 106118701 A discloses a high-charcoal-yielding biomass carbonization process. This method optimizes the full-process process parameters of biomass carbonization, improving the biochar yield and the recovery rate of other products. After pretreatment, the biomass raw material is compacted and carbonized in an open carbonization furnace. After carbonization, the flue gas is treated and products such as biochar and wood vinegar are recovered. However, the carbonization furnace of this carbonization process is open, and the anaerobic or anoxic environment within the furnace is not controlled. This may cause organic matter loss in the biomass during carbonization. Moreover, the amount of biomass that can be processed by this method is very small, making it difficult to apply on a large scale.

[0005] In addition, mainstream biomass dryers use rotary kilns or reactor structures. Although rotary kilns can dry continuously, they suffer from high heat loss from exhaust gas, which reduces biomass utilization. Reactors cannot dry continuously and have low processing capacity.

[0006] In summary, the current biomass carbonization technology still has problems such as low carbon yield, small processing capacity, and insufficient biomass utilization. Summary of the Invention

[0007] The purpose of the present invention is to solve the problems mentioned in the background technology and provide a system and method for biomass carbonization, which can realize the large-scale production of biochar while achieving efficient biomass utilization.

[0008] In order to achieve the above objectives, the present invention provides a biomass carbonization system in a first aspect, the system comprising a fluidized bed dryer, a carbonization furnace and a burner.

[0009] The fluidized bed dryer utilizes a gas drying medium to fluidize and dry the biomass raw material to be carbonized, thereby obtaining a dried material and discharging waste gas.

[0010] The carbonization furnace is used to utilize the heat of the first flue gas generated by the burner to pyrolyze and carbonize the dried material, so that the dried material is pyrolyzed to obtain biochar and pyrolysis gas, and the first flue gas after heat release is discharged as the second flue gas;

[0011] The burner is used for burning fuel including the pyrolysis gas to obtain first flue gas.

[0012] Preferably, the system further comprises a crusher and / or a purification unit, wherein

[0013] The crusher is used to reduce the particle size of the biomass raw material entering the fluidized bed dryer to facilitate the transportation of the biomass raw material and subsequent fluidized bed drying; and / or

[0014] The purification unit is used to remove pollutants including dust and acidic gases from the waste flue gas discharged from the fluidized bed dryer, ensuring that the waste flue gas meets emission standards.

[0015] Preferably, the fluidized bed dryer comprises a shell, a raw material inlet, a gas drying medium inlet, a movable plate and an air distribution plate; wherein,

[0016] The movable plate is longitudinally arranged in the shell, and is used to divide the interior of the shell into a drying area on the right and a separation area on the left. A gap is left between the top of the movable plate and the top of the shell to form a first communication port. The height of the first communication port is adjustable by moving the movable plate up and down.

[0017] The drying zone and the separation zone are connected via the first communication port;

[0018] The air distribution plate is arranged at the lower part of the drying area, thereby dividing the drying area into an air inlet chamber and a drying chamber located above the air inlet chamber;

[0019] The air inlet chamber is further provided with the gas drying medium inlet, and the air inlet chamber is used to introduce the gas drying medium from the gas drying medium inlet and distribute the gas drying medium through the air distribution plate and then enter the drying chamber upward;

[0020] The drying chamber sidewall is further provided with the raw material inlet, and the drying chamber is used to fluidize and dry the biomass raw material from the raw material inlet using the gas drying medium, and to deliver the dried gas-solid mixture material into the separation zone from the first connecting port;

[0021] The separation zone is provided with a drying material outlet and a waste flue gas outlet. The separation zone is used to perform gas-solid separation on the gas-solid mixture material, and the separated solid material is sent out from the drying material outlet as a drying material, and the separated gas material is sent out from the waste flue gas outlet.

[0022] A second aspect of the present invention provides a method for carbonizing biomass using the system, comprising the following steps:

[0023] (1) In the fluidized bed dryer, the biomass raw material is dried using a gas drying medium to obtain a dried material;

[0024] (2) In the carbonization furnace, the dried material is pyrolyzed and carbonized using the first flue gas generated by the burner to obtain biochar and pyrolysis gas, and the first flue gas after heat release is discharged as the second flue gas;

[0025] (3) In the burner, the pyrolysis gas is burned to obtain a first flue gas, which is circulated for pyrolysis carbonization.

[0026] Compared with the prior art, the present invention has the following technical effects:

[0027] First, the biomass carbonization system of the present invention significantly improves the overall biomass energy utilization rate through the cascaded utilization of hot flue gas and the recycling of biomass pyrolysis byproducts. Specifically, the byproducts of carbonization and pyrolysis are burned, generating a first flue gas that provides energy for the carbonization and pyrolysis of biomass in the carbonization furnace. The second flue gas, generated by exchanging heat between the high-temperature biochar and air, provides energy for the fluidized bed dryer and / or serves as an oxidant to be blown into the burner, improving combustion efficiency. Furthermore, the system can process large quantities of biomass and is well-adapted to a variety of biomass types.

[0028] 2. In the biomass carbonization system of the present invention, the fluidized bed dryer adjusts the moisture content of the biomass by setting the height of the movable plate, and realizes the gas-solid separation of the drying material and the exhaust gas through structural design, which can control the moisture content of the drying material below 15%, reducing the energy consumption required for removing moisture during the subsequent pyrolysis and carbonization of the drying material, and improving the utilization rate of the pyrolysis gas generated by the carbonization furnace.

[0029] 3. In the biomass carbonization system of the present invention, the fluidized bed dryer utilizes a heat source to directly contact and dry the biomass to be dried, which greatly improves the biomass drying capacity of the equipment and simultaneously improves the biomass carbonization capacity.

[0030] Fourth, in the biomass carbonization system of the present invention, the separation zone in the fluidized bed dryer utilizes an internal separation principle, avoiding the space waste, equipment redundancy, and increased risk of clogging caused by external cyclone separators. Compared to conventional rotary kiln or reactor dryers, the fluidized bed dryer of the present invention offers superior heat exchange and enables rapid biomass drying.

[0031] 5. In the biomass carbonization system of the present invention, the carbonization furnace uses a burner to generate first flue gas to perform low-temperature carbonization on the dried biomass, which can minimize the generation of biomass gas and tar and increase the yield of biochar. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A schematic diagram of a biomass carbonization system provided by the present invention.

[0033] Figure 2 A schematic diagram of a fluidized bed dryer provided by the present invention, wherein:

[0034] 1-shell, 2-raw material inlet, 3-drying material outlet, 4-gas drying medium inlet, 5-waste flue gas outlet, 6-movable plate, 7-air distribution plate, 8-air hole, 9-drying chamber, 10-air inlet chamber, 11-first connecting port, 12-partition, 13-second connecting port, 14-third connecting port, 15-baffle. DETAILED DESCRIPTION

[0035] The following further describes the technical solutions and effects of the present invention in conjunction with specific embodiments and examples. The following embodiments and examples are intended only to illustrate the present invention and are not intended to be limited to the following embodiments and examples. Simple modifications to the present invention that utilize the concepts of the present invention fall within the scope of protection claimed herein.

[0036] like Figure 1 As shown, the first aspect of the present invention provides a biomass carbonization system, the system comprising a fluidized bed dryer ( Figure 1 dryer in Chinese), carbonizing furnace and burner.

[0037] In the present invention, the fluidized bed dryer utilizes a gas drying medium to fluidize and dry the biomass raw material to be carbonized, thereby obtaining a dried material and discharging waste gas.

[0038] like Figure 2As shown, the fluidized bed dryer includes a shell 1, a raw material inlet 2, a gas drying medium inlet 3, a movable plate 6 and an air distribution plate 7.

[0039] In the present invention, the movable plate 6 is longitudinally arranged in the shell 1, and is used to divide the interior of the shell into a drying area on the right and a separation area on the left, wherein a gap is left between the top of the movable plate 6 and the top of the shell 1 to form a first connecting port 11, and the height of the first connecting port 11 is adjustable through the longitudinal movement of the movable plate 6.

[0040] In the present invention, the drying zone and the separation zone are connected via a first communication port 11 , and the selective discharge of the biomass raw material in the drying chamber 9 is controlled by adjusting the size of the first communication port 11 (ie, the height of the movable plate 6 ).

[0041] Specifically, as the drying gas passes through air distribution plate 7 via air holes 8, the biomass feedstock entering drying chamber 9 via feedstock inlet 2 gradually becomes fluidized. Due to density, biomass with high density (i.e., high moisture content) resides in the lower layers of drying chamber 9, while biomass with low density (i.e., low moisture content) floats in the upper layers. Adjusting the height of movable plate 6 controls the floating height of the biomass within drying chamber 9, allowing biomass with different moisture contents to be selectively removed, achieving precise control of the moisture content of the dried material.

[0042] In the present invention, the air distribution plate 6 is arranged at the lower part of the drying zone, thereby dividing the drying zone into an air inlet chamber 10 and a drying chamber 9 located above the air inlet chamber 10 .

[0043] In some embodiments, the air inlet chamber 10 may be composed of one or more small air chambers, each small air chamber or multiple small air chambers corresponding to a gas drying medium inlet 4, and each gas drying medium inlet 4 can pass through gas drying media of different temperatures and pressures.

[0044] In some embodiments, the air distribution plate 7 is tilted in the housing 1 , with an angle of 2-10° with the horizontal plane, and the raw material inlet 2 is located on the upward side of the air distribution plate 7 .

[0045] Preferably, the air distribution plate 7 is connected to the side wall of the housing 1 in a detachable manner;

[0046] Preferably, the surface of the air distribution plate 7 contains a plurality of air holes 8 with a spacing of 2-8 mm.

[0047] The inventors have found that the inclined arrangement of the air distribution plate 7 is conducive to the flow of biomass toward the separation zone during the fluidization process, thereby achieving a trend of the wet biomass material gradually drying from the inlet to the separation zone.

[0048] In some embodiments, air distribution plates 7 are constructed from round steel or / and steel pipes, with a spacing of 1-20 mm between the round steel or / and steel pipes to form channels for the fluidizing medium, promoting biomass fluidization. Adjusting the spacing between the round steel or / and steel pipes allows for flexible processing of biomass from different sources.

[0049] In the present invention, the air inlet chamber 10 is further provided with a gas drying medium inlet 4 , and the air inlet chamber 10 is used to introduce the gas drying medium from the gas drying medium inlet 2 and distribute it through the air distribution plate 7 before entering the drying chamber 9 upwards.

[0050] In the present invention, a raw material inlet 2 is further provided on the side wall of the drying chamber 9. The drying chamber 9 is used to fluidize and dry the biomass raw material from the raw material inlet 2 using a gas drying medium, and to deliver the dried gas-solid mixture material into the separation zone from the first connecting port 11.

[0051] In the present invention, the separation zone is provided with a drying material outlet 3 and a waste flue gas outlet 5. The separation zone is used to perform gas-solid separation on the gas-solid mixture material, and the separated solid material is sent out as drying material from the drying material outlet 3, and the gas material is sent out from the waste flue gas outlet 5.

[0052] In some embodiments, the bottom of the separation zone is conical, and the drying material outlet 3 is arranged at the lowest end of the conical bottom of the separation zone.

[0053] In some embodiments, a partition 12 is further provided in the separation zone, and the partition 12 extends downward from the top of the separation zone and leaves a gap with the bottom of the separation zone to form a second connecting port 13. The partition 12 divides the separation zone into a preliminary gas-solid separation area on the right and a secondary gas-solid separation area on the left; wherein, the top of the preliminary gas-solid separation area is connected to the drying chamber 9 through the first connecting port 11, and the bottom of the preliminary gas-solid separation area is connected to the secondary gas-solid separation area through the second connecting port 13.

[0054] Further explanation: the waste flue gas outlet 5 is arranged at the upper part of the secondary gas-solid separation area and the lower part of the third connecting port 14. The waste flue gas outlet 5 can be provided with a deflector 15, the center of the arc of which points to the center of the waste flue gas outlet 5, so that the waste flue gas rotates around the waste flue gas outlet 5 and is discharged.

[0055] Through the above structure, the exhaust gas and large-size biomass particles can be separated in the dryer, reducing the number of subsequent equipment and the equipment footprint.

[0056] In some embodiments, a third communication port 14 is further provided above the partition 12, connecting the primary gas-solid separation region with the upper portion of the secondary gas-solid separation region. This port 14 is positioned above the exhaust gas outlet 5. This structure primarily increases the exhaust gas flow rate through the third communication port 14, which then reverses the exhaust gas flow through the housing 1, creating a swirling flow around the exhaust gas outlet 5 and achieving solid-gas separation through centrifugal force and gravity. The separated large-particle biomass is discharged through the second communication port 13 to the drying material outlet 3.

[0057] Preferably, the preliminary gas-solid separation area is located directly above the drying material outlet 3 .

[0058] The inventors discovered that the exhaust gas outlet 5 and the preliminary gas-solid separation area on the right side form an internal circulation, and solid-gas separation is achieved by centrifugal force. The solid material is discharged from the drying material outlet 3 through the bottom (the second connecting port 13), and the mixture of gaseous material (mainly exhaust gas, also called the fourth flue gas) and small-particle drying material still flows in from the third connecting port 14 on the right side of the exhaust gas outlet 5, thereby ensuring the effectiveness of gas-solid separation.

[0059] In some embodiments, the drying material outlet 3 of the fluidized bed dryer is equipped with a star-shaped discharge valve or other unloading equipment to achieve uniform discharge of biomass and prevent the entry of external air. The drying material outlet 3 of the fluidized bed dryer is also provided with multiple humidity sensors to monitor the moisture content of the drying material.

[0060] The inventors have discovered that the star-shaped discharge valve not only controls the discharge speed, but also plays a sealing role, preventing gas leakage or external air from entering the shell 1, thereby preventing the gas from breaking the flow track of the fourth flue gas, that is, destroying the fourth flue gas from flowing through the third connecting port 14 and then entering the exhaust gas outlet 5, thereby reducing or failing to achieve the gas-solid separation effect of the fourth flue gas.

[0061] In the present invention, the carbonization furnace is used to utilize the heat of the first flue gas generated by the burner to pyrolyze and carbonize the dried material, so that the dried material is pyrolyzed to obtain biochar and pyrolysis gas, and the first flue gas after heat release is discharged as the second flue gas.

[0062] Preferably, the carbonization furnace is connected to the gas drying medium inlet 2 via a second flue gas pipe, so as to feed the second flue gas into the air inlet chamber 10 as at least part of the gas drying medium; and / or

[0063] The third flue gas obtained by heat exchange between air and the biochar obtained by pyrolysis is sent to the gas drying medium inlet 2 as part of the gas drying medium through the third flue gas pipe.

[0064] In some embodiments, the gas drying medium is a second flue gas obtained by heat release of the first flue gas, and / or a third flue gas generated by heat exchange between air and biochar at a high temperature.

[0065] In some embodiments, the carbonization furnace is a rotary kiln or a spiral structure, which can reduce the loss of organic matter during carbonization. The carbonization furnace is heated by flue gas indirect heating, so there is no problem of separation of the gas drying medium and the pyrolysis gas.

[0066] Preferably, the carbonization furnace is provided with a temperature sensor (such as an infrared temperature sensor) for real-time monitoring of the working conditions in the furnace and an air supply port for blowing air in to adjust the furnace temperature. The air supply port can be provided at the first flue gas inlet or separately.

[0067] In the present invention, the burner is used to burn fuel including the pyrolysis gas to obtain the first flue gas, which has a higher temperature than the second flue gas.

[0068] In some embodiments, the system further comprises a crusher and / or a purification unit, wherein

[0069] The crusher is used to reduce the particle size of the biomass raw material entering the fluidized bed dryer to facilitate the transportation of the biomass raw material and subsequent fluidized bed drying;

[0070] The purification unit is used to remove pollutants including dust and acidic gases from the waste flue gas discharged from the fluidized bed dryer (i.e., the gas material discharged from the waste flue gas outlet 5), ensuring that the gas material (i.e., waste flue gas, or called the fourth flue gas) meets the emission standards.

[0071] Preferably, the purification unit is provided with a dust removal device (such as a Buchner dust collector in the art) and a gas purification device in sequence along the gas flow direction.

[0072] More preferably, the gas purification device can be selected from the art, such as a purification tower filled with alkaline liquid for removing acidic gases in waste flue gas; the dust removal device can be selected from the Buchner dust collector in the art.

[0073] A second aspect of the present invention provides a method for carbonizing biomass using the above system, the method comprising the following steps:

[0074] (1) In the fluidized bed dryer, the biomass raw material is dried using a gas drying medium to obtain a dried material;

[0075] (2) In the carbonization furnace, the dried material is pyrolyzed and carbonized using the first flue gas generated by the burner to obtain biochar and pyrolysis gas, and the first flue gas after heat release is discharged as the second flue gas;

[0076] (3) In the burner, the pyrolysis gas is burned to obtain a first flue gas, which is circulated for pyrolysis carbonization.

[0077] In some embodiments, in step (1), the biomass raw material has a wide range of sources and can be selected from at least one of plant biomass, animal biomass, microbial biomass and organic waste; wherein,

[0078] The plant biomass may be selected from wood, crops and their by-products, leaves, grasses; and / or

[0079] The animal biomass may be selected from animal manure; and / or

[0080] The microbial biomass may be selected from algae, fungi; and / or

[0081] The organic waste can be selected from municipal solid waste, domestic garbage, and sludge from sewage treatment plants.

[0082] In some embodiments, in step (1), the particle size of the biomass raw material is ≤150 mm, and the moisture content of the dried material is ≤15%.

[0083] Preferably, in step (1), the gas drying medium is the second flue gas obtained after the first flue gas releases heat, and / or the third flue gas generated after heat exchange between air and biochar at high temperature.

[0084] In some embodiments, in step (1), the gaseous material (i.e., waste flue gas, also referred to as fourth flue gas) generated after the drying is discharged after dust removal and removal of acidic gases.

[0085] In some embodiments, in step (2), when the pyrolysis carbonization is performed, the temperature in the carbonization furnace is 300-350° C., and the residence time of the dried material in the carbonization furnace is ≤10 min. The temperature and residence time can be controlled by the feed rate of the dried material and the amount of air blown into the air supply port.

[0086] The inventors have discovered that by controlling the feed rate of the drying material, the temperature and time of pyrolysis carbonization, the oxygen content in the carbonization furnace and other conditions, the carbonization rate of the biomass can be increased, more biochar can be obtained without producing tar and wood vinegar, and the charcoal yield of the dry biomass can reach more than 76%.

[0087] The inventors have discovered that excessively high temperatures in the carbonization furnace will exacerbate the loss of volatile matter in biomass. The system proposed in the present invention enables biomass to produce the most biochar, rather than biomass gas and tar. Biochar is conducive to storage and transportation and is one of the raw materials for biomass entrained flow gasification to produce methanol.

[0088] In some embodiments, in step (2), the high-temperature biochar is initially cooled to 100°C using air, thereby obtaining the third flue gas and the initially cooled biochar. Subsequently, the initially cooled biochar is further cooled (e.g., by water cooling) to below 50°C to obtain low-temperature biochar that is convenient for collection and storage.

[0089] Preferably, the temperature of the biochar after heat exchange is less than 80°C.

[0090] Preferably, the temperature of the second flue gas is 100-200°C

[0091] In some embodiments, in step (3), the pyrolysis gas is directly fed into a burner for combustion. If a large amount of the first flue gas is required in step (2), the burner may be supplemented with fuel, such as at least one selected from biomass, natural gas, and fuel oil. During the combustion of the pyrolysis gas and / or fuel, the second flue gas may be introduced as an oxidant instead of air to improve combustion efficiency.

[0092] In some embodiments, at least one of the gas drying medium, pyrolysis gas, first flue gas, second flue gas, third flue gas and fourth flue gas (gas material or waste flue gas) mentioned in the method is transported by a method well known in the art, such as by an induced draft fan.

[0093] In some embodiments, the system and method provided by the present invention can be used for large-scale biomass carbonization, with a biomass processing capacity of more than 20 t / h.

Claims

1. A biomass carbonization system, characterized in that: The system includes a fluidized bed dryer, a carbonization furnace and a burner. The fluidized bed dryer utilizes a gas drying medium to fluidize and dry the biomass raw material to be carbonized, thereby obtaining a dried material and discharging waste gas. The carbonization furnace is used to utilize the heat of the first flue gas generated by the burner to pyrolyze and carbonize the dried material, so that the dried material is pyrolyzed to obtain biochar and pyrolysis gas, and the first flue gas after heat release is discharged as the second flue gas; The burner is used for burning fuel including the pyrolysis gas to obtain first flue gas.

2. The system according to claim 1, wherein: The system further comprises a crusher and / or a cleaning unit, wherein The crusher is used to reduce the particle size of the biomass raw material entering the fluidized bed dryer to facilitate the transportation of the biomass raw material and subsequent fluidized bed drying; and / or The purification unit is used to remove pollutants including dust and acidic gases from the waste flue gas discharged from the fluidized bed dryer, ensuring that the waste flue gas meets emission standards.

3. The system according to claim 1 or 2, characterized in that The fluidized bed dryer comprises a shell, a raw material inlet, a gas drying medium inlet, a movable plate and an air distribution plate; wherein, The movable plate is longitudinally arranged in the shell, and is used to divide the interior of the shell into a drying area on the right and a separation area on the left. A gap is left between the top of the movable plate and the top of the shell to form a first communication port. The height of the first communication port is adjustable by moving the movable plate up and down. The drying zone and the separation zone are connected via the first communication port; The air distribution plate is arranged at the lower part of the drying area, thereby dividing the drying area into an air inlet chamber and a drying chamber located above the air inlet chamber; The air inlet chamber is further provided with the gas drying medium inlet, and the air inlet chamber is used to introduce the gas drying medium from the gas drying medium inlet and distribute the gas drying medium through the air distribution plate and then enter the drying chamber upward; The drying chamber sidewall is further provided with the raw material inlet, and the drying chamber is used to fluidize and dry the biomass raw material from the raw material inlet using the gas drying medium, and to deliver the dried gas-solid mixture material into the separation zone from the first connecting port; The separation zone is provided with a drying material outlet and a waste flue gas outlet. The separation zone is used to perform gas-solid separation on the gas-solid mixture material, and the separated solid material is sent out from the drying material outlet as a drying material, and the separated gas material is sent out from the waste flue gas outlet.

4. The system according to any one of claims 1 to 3, characterized in that The carbonization furnace is connected to the gas drying medium inlet via a second flue gas pipe, so as to deliver the second flue gas as at least part of the gas drying medium into the air inlet chamber; and / or The third flue gas obtained by heat exchange between air and the biochar obtained by pyrolysis is sent into the gas drying medium inlet as part of the gas drying medium through the third flue gas pipe.

5. The system according to any one of claims 1 to 4, characterized in that The bottom of the separation zone is conical, and the drying material outlet is arranged at the lowest end of the conical bottom of the separation zone; The separation zone is further provided with a partition plate, which extends downward from the top of the separation zone and is spaced apart from the bottom of the separation zone to form a second communication port. The partition plate divides the separation zone into a primary gas-solid separation zone on the right and a secondary gas-solid separation zone on the left. The top of the primary gas-solid separation zone is connected to the drying chamber via the first communication port, and the bottoms of the primary gas-solid separation zone and the secondary gas-solid separation zone are connected via the second communication port. Preferably, a third communication port is further provided on the upper portion of the partition plate for connecting the upper portion of the preliminary gas-solid separation region with the upper portion of the secondary gas-solid separation region, and the third communication port is higher than the exhaust gas outlet; More preferably, the exhaust gas outlet is arranged at the upper part of the secondary gas-solid separation area; More preferably, the preliminary gas-solid separation area is located directly above the drying material outlet.

6. The system according to any one of claims 1 to 5, characterized in that The air distribution plate is tilted in the housing, with an angle of 2-10° to the horizontal plane; Preferably, the raw material inlet is located on the upward side of the air distribution plate; Preferably, the air distribution plate is connected to the side wall of the shell in a detachable manner; Preferably, the surface of the air distribution plate contains air holes with a spacing of 2-8 mm.

7. The system according to any one of claims 1 to 6, characterized in that The drying material outlet of the fluidized bed dryer is provided with a humidity sensor and a sealing device; and / or The carbonization furnace is a rotary kiln or a spiral structure; Preferably, the carbonization furnace is provided with a temperature sensor and an air supply port.

8. A method for carbonizing biomass using the system according to any one of claims 1 to 7, the method comprising the following steps: (1) In the fluidized bed dryer, the biomass raw material is dried using a gas drying medium to obtain a dried material; (2) In the carbonization furnace, the dried material is pyrolyzed and carbonized using the first flue gas generated by the burner to obtain biochar and pyrolysis gas, and the first flue gas after heat release is discharged as the second flue gas; (3) In the burner, the pyrolysis gas is burned to obtain a first flue gas, which is circulated for pyrolysis carbonization.

9. The method according to claim 8, characterized in that In step (1), The biomass raw material is selected from at least one of plant biomass, animal biomass, microbial biomass and organic waste; preferably, the particle size of the biomass raw material is ≤150 mm, and the moisture content of the dried material is ≤15%; and / or The gas material generated after the drying is discharged after dust removal and acid gas removal; and / or The gas drying medium is a second flue gas obtained by heat release from the first flue gas, and / or a third flue gas generated by heat exchange between air and biochar at high temperature; Preferably, the temperature of the second flue gas is 100-200°C; Preferably, the temperature of the biochar after heat exchange is less than 80°C; Preferably, the heat exchange method includes: first using air to initially cool the high-temperature biochar to 100°C, while obtaining the third flue gas, and then further cooling the initially cooled biochar to below 50°C through water cooling heat exchange.

10. The method according to claim 8 or 9, characterized in that In step (2), when the pyrolysis carbonization is carried out, The temperature in the carbonization furnace is 300-350°C; and / or The residence time of the dried material in the carbonization furnace is ≤10 min.

Images