Biomass pyrolysis poly-generation device with gas circulation system and biomass pyrolysis poly-generation method

Abstract

The invention relates to the field of high-value utilization of organic solid wastes, in particular to a biomass pyrolysis poly-generation device with a gas circulation system, which comprises a pretreatment furnace, a low-temperature pyrolysis furnace, a high-temperature carbonization furnace, a condenser and a combustor. In addition, the invention also provides a pyrolysis poly-generation method, raw materials pass through the pretreatment furnace and then enter the low-temperature pyrolysis furnace for pyrolysis, pyrolysis gas is subjected to separation and condensation treatment to obtain high-combustion-performance bio-oil, non-condensable gas is combusted to obtain carbon dioxide-rich high-temperature flue gas, the carbon dioxide-rich high-temperature flue gas and pyrolytic carbon enter the high-temperature carbonization furnace, and the high-temperature carbonization furnace is used for carbonization. The pyrolytic carbon is further carbonized into activated carbon, and waste heat is recycled for the pretreatment process. Pretreatment, low-temperature pyrolysis and high-temperature carbonization are coupled in one system, carbon dioxide-rich high-temperature flue gas obtained through pyrolysis gas combustion is used for providing an activating agent and heat for the carbonization process, waste heat generated in the high-temperature carbonization process is used for providing heat needed by pretreatment, and efficient pyrolysis and carbonization co-production is achieved.

Description

Technical Field

[0001] The invention relates to the field of high-value utilization of organic solid waste, and in particular to a biomass pyrolysis polygeneration device and method with a gas circulation system. Background Art

[0002] With the gradual depletion of fossil energy and the intensification of environmental pollution, the development and utilization of renewable energy has become an urgent need for the world. Biomass, as a widely existing renewable resource, is green, pollution-free and has low carbon dioxide emissions. Pyrolysis technology is a very important means of biomass utilization, which can transform low-grade biomass resources into products with higher added value, which not only improves the utilization quality of biomass energy but also improves its utilization efficiency.

[0003] During the pyrolysis process, the moisture content of the raw material has a significant impact on the entire pyrolysis process. The presence of water will absorb part of the heat, reduce the temperature of the pyrolysis reaction, and slow down the reaction rate. At the same time, raw materials with high moisture content will increase the water content and oxygen content in the bio-oil during the pyrolysis process, and will also cause the calorific value of the pyrolysis gas to decrease. By properly drying and pre-treating the raw materials, the moisture content can be reduced, the efficiency of the pyrolysis reaction and the quality of the products can be optimized, thereby improving the economy of the pyrolysis process and the application value of the products. Chinese patent CN202211008135.3 discloses a system and method for improving the continuous baking-pyrolysis of biomass, which improves the energy density of the raw material by coupling baking before pyrolysis, and the bio-oil components obtained after pyrolysis are significantly improved, and the water content and oxygen content of the obtained bio-oil are significantly reduced. In addition, biochar, as an important solid phase product in the pyrolysis process, is regarded as an environmentally friendly multifunctional material, which is characterized by not only a large specific surface area and pore size. However, compared with activated carbon, the processing efficiency and stability of biochar are still relatively low, resulting in great limitations in the application of biochar. In order to improve the quality of biochar, carbon dioxide activation is an important biochar activation method. During the activation process of biochar, carbon dioxide can generate a pore structure dominated by micropores or mesopores, with a larger specific surface area, which is suitable for applications such as macromolecular gas adsorption and air purification. It is worth noting that the pyrolysis process of biomass often produces a large amount of non-condensable gas, including CO2, CO, CH4, etc., which will produce CO2-rich gas after combustion, which can be used for the activation of pyrolytic carbon.

[0004] However, currently, separate reaction devices are generally used for biomass roasting pretreatment and biochar activation, and they are carried out in independent processes. It is impossible to achieve coordinated regulation in the same reaction process. At the same time, both pretreatment and pyrolysis require a certain temperature, which greatly increases the power consumption of the entire process route and has poor technical and economic efficiency.

[0005] Therefore, it is urgent to develop simple and efficient biomass pyrolysis equipment for the co-production of activated carbon and bio-oil with high combustion performance, avoid complex pretreatment, pyrolysis and carbonization equipment, and at the same time improve energy utilization efficiency to achieve high-value utilization and resource utilization of biomass. Summary of the invention

[0006] 1. Technical issues to be resolved

[0007] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a biomass pyrolysis polygeneration device and method with a gas circulation system to solve the problem of low utilization efficiency of biomass in the prior art.

[0008] (II) Technical solution

[0009] In order to achieve the above-mentioned object, the biomass pyrolysis polygeneration device with a gas circulation system of the present invention comprises:

[0010] A pretreatment furnace, wherein the pretreatment furnace is a hollow tube arranged obliquely, the head end of the pretreatment furnace is lower than the tail end, a feed port is provided at the top of the head end of the pretreatment furnace, a circulating feeder is provided inside the pretreatment furnace, and a plurality of feeding baffles are spaced apart on the circulating feeder; a liquid discharge port is provided at the bottom of the head end of the pretreatment furnace, and a waste heat flue gas recovery port is also provided at the head end of the pretreatment furnace;

[0011] A low-temperature pyrolysis furnace, wherein the low-temperature pyrolysis furnace is a hollow tube arranged obliquely, the end of the low-temperature pyrolysis furnace is lower than the head end, and the end of the pretreatment furnace is butt-jointed with and connected to the head end of the low-temperature pyrolysis furnace; a pyrolysis screw feeder is arranged inside the low-temperature pyrolysis furnace, a pyrolysis gas outlet is arranged at the top of the end of the low-temperature pyrolysis furnace, and a pyrolysis charcoal outlet is arranged at the bottom of the end of the low-temperature pyrolysis furnace;

[0012] A high-temperature carbonization furnace, wherein the high-temperature carbonization furnace is a horizontally arranged hollow tube, and a carbonization screw feeder is arranged inside the high-temperature carbonization furnace; the pyrolytic carbon outlet is connected to the head end of the high-temperature carbonization furnace, and an activated carbon outlet is arranged at the bottom of the end of the high-temperature carbonization furnace, and a waste heat flue gas outlet is arranged at the end of the high-temperature carbonization furnace, and the waste heat flue gas outlet is connected to the waste heat flue gas recovery port;

[0013] A condenser, wherein the inlet of the condenser is connected to the pyrolysis gas outlet, and the condenser is also provided with a liquid product outlet;

[0014] A burner, wherein the inlet of the burner is connected to the outlet of the condenser, and the outlet of the burner is connected to the head end of the high-temperature carbonization furnace.

[0015] Optionally, the pretreatment furnace is a hollow square tube;

[0016] The low-temperature pyrolysis furnace and the high-temperature carbonization furnace are both hollow tubes with a D-shaped cross-section. The tops of the low-temperature pyrolysis furnace and the high-temperature carbonization furnace are both flat walls, and a smoke exhaust channel is formed between the flat wall and the corresponding pyrolysis screw feeder or the carbonization screw feeder.

[0017] Optionally, the angle formed by the axis of the pretreatment furnace and the axis of the low-temperature pyrolysis furnace is 90° to 120°.

[0018] Optionally, an upwardly protruding material blocking baffle is provided at the bottom of the joint between the end of the pretreatment furnace and the head end of the low-temperature pyrolysis furnace; the feeding baffle is a soft plate, and the material blocking baffle is arranged parallel to the feeding baffle; the gap between the material blocking baffle and the wall of the circulating loader is 1 to 3 mm.

[0019] Optionally, the interval between adjacent feeding baffles is 20 to 50 mm; the angle between the circulating feeder and the feeding baffle is 45° to 135°; and the gap between the feeding baffle and the inner wall of the pretreatment furnace is 1 to 3 mm.

[0020] Optionally, the outer diameter of the spiral blade of the pyrolysis screw feeder is 0.5 to 0.8 times the outer diameter of the spiral blade of the carbonization screw feeder; the pitch of the spiral blade of the pyrolysis screw feeder is 2 to 5 times the pitch of the spiral blade of the carbonization screw feeder.

[0021] Optionally, the circulating loader is a conveyor belt.

[0022] Furthermore, the present invention also provides a pyrolysis polygeneration method, which is implemented based on the above-mentioned biomass pyrolysis polygeneration device with a gas circulation system, and comprises:

[0023] S1, the circulating feeder rotates clockwise, driving the feeding baffle to move, and the pyrolysis screw feeder and the carbonization screw feeder rotate at a set speed; at the same time, the low-temperature pyrolysis furnace and the high-temperature carbonization furnace are heated to the set temperature respectively;

[0024] S2, adding raw materials from the feed port, the feed baffle drives the raw materials to move in the pretreatment furnace, and under the baking effect of the pretreatment furnace and the extrusion effect of the feed baffle, the raw materials are fed into the low-temperature pyrolysis furnace after removing excess moisture;

[0025] S3, the raw material is heated in the low-temperature pyrolysis furnace and undergoes a pyrolysis reaction to produce pyrolysis char and pyrolysis gas; the pyrolysis gas enters the condenser through the pyrolysis gas outlet, the pyrolysis oil obtained after condensation and separation is discharged from the liquid product outlet, and the remaining incondensable gas enters the burner for combustion to generate carbon dioxide-rich high-temperature flue gas, and the carbon dioxide-rich high-temperature flue gas and pyrolysis char enter the high-temperature carbonization furnace together;

[0026] S4. The high-temperature flue gas rich in carbon dioxide generated by the burner enters the high-temperature carbonization furnace, and the pyrolytic carbon is further heated in the high-temperature carbonization furnace, and a carbonization reaction occurs under the physical activation of the high-temperature flue gas rich in carbon dioxide, thereby generating waste heat flue gas and activated carbon; the activated carbon is discharged through the activated carbon outlet and collected, and the waste heat flue gas is sent back to the pretreatment furnace through the waste heat flue gas outlet.

[0027] Optionally, the temperature of the pretreatment furnace is provided by the waste heat flue gas from the high-temperature carbonization furnace, and the temperature of the pretreatment furnace is 150-200°C; the temperature of the low-temperature pyrolysis furnace is electrically heated, and the temperature of the low-temperature pyrolysis furnace is 400-600°C; the temperature of the high-temperature carbonization furnace is provided by the high-temperature flue gas rich in carbon dioxide from the burner, and the temperature of the high-temperature carbonization furnace is 800-1000°C; the temperature of the condenser is 0-20°C.

[0028] (III) Beneficial effects

[0029] The technical solution of the present invention provides a biomass pyrolysis multi-generation device and method with a gas circulation system, which couples pretreatment, low-temperature pyrolysis and high-temperature carbonization in one device, uses the waste heat generated in the high-temperature carbonization process to provide the required heat for the pretreatment stage, and uses the high-temperature flue gas rich in carbon dioxide obtained by burning pyrolysis gas to provide heat and activator for the carbonization process, effectively improving the energy utilization efficiency. The biomass raw material first enters the pretreatment furnace, and the initial pretreatment of the raw material is achieved through the extrusion of the feeding baffle on the circulating feeder and the heat provided by the waste heat flue gas. After removing moisture, it enters the low-temperature pyrolysis furnace for pyrolysis reaction to generate pyrolysis gas and pyrolysis char. The pyrolysis gas enters the condenser for separation and condensation to obtain liquid products with low moisture content and low oxygen content and non-condensable high calorific value gas. The non-condensable high calorific value gas enters the burner for combustion to obtain carbon dioxide-rich high-temperature flue gas. The carbon dioxide-rich high-temperature flue gas and pyrolysis char enter the high-temperature carbonization furnace together. Under the physical activation of the carbon dioxide-rich high-temperature flue gas, it is further carbonized into a pore structure dominated by micropores or mesopores, with a larger specific surface area, and more stable and adsorption capacity. The waste heat is recycled to the pretreatment process to form a multi-product system that jointly generates a variety of high-value products, improves the utilization rate of waste heat and the comprehensive utilization efficiency of energy, and also improves the utilization efficiency of biomass resources.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] (1) High space utilization: No additional auxiliary equipment is required, and the raw material pretreatment, pyrolysis and carbonization reaction sections are arranged in the same furnace body. The device structure is compact and the space utilization is improved.

[0032] (2) High energy utilization rate: The waste heat flue gas recovery method can recycle the pyrolysis gas generated during the pyrolysis process, which not only reduces dependence on external energy, but also improves the overall energy efficiency of the system, further reduces energy waste, and reduces operating costs.

[0033] (3) Flexible process control: The pretreatment furnace, low-temperature pyrolysis furnace and high-temperature carbonization furnace operate independently, and by adjusting the operating parameters of different furnaces, efficient processing of different biomass materials can be achieved, which has good process flexibility.

[0034] (4) Co-production of high-value products: The device couples the pretreatment, pyrolysis and carbonization processes to simultaneously produce a variety of valuable products, including bio-oil and activated carbon with high combustion performance. Biomass raw materials can be converted into a variety of usable resources to the maximum extent, thereby improving the overall economic benefits.

[0035] (5) Environmentally friendly: The pyrolysis and carbonization of biomass reduces the pollution emissions caused by traditional combustion. At the same time, the recycling of pyrolysis gas also reduces waste gas emissions, helps reduce carbon footprint, meets environmental protection requirements, and is significantly environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic structural diagram of a biomass pyrolysis polygeneration device with a gas circulation system according to the present invention.

[0037] [Description of Reference Numerals]

[0038] 1: pretreatment furnace; 11: feed port; 12: circulating feeder; 13: feed baffle; 14: drain port;

[0039] 2: low temperature pyrolysis furnace; 21: pyrolysis screw feeder; 22: pyrolysis gas outlet; 23: pyrolysis carbon outlet; 24: material blocking baffle;

[0040] 3: High temperature carbonization furnace; 31: Carbonization screw feeder; 32: Activated carbon outlet; 33: Waste heat flue gas outlet;

[0041] 4: condenser; 41: liquid product outlet;

[0042] 5: Burner. DETAILED DESCRIPTION

[0043] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below through specific implementation modes in conjunction with the accompanying drawings.

[0044] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0045] In addition, in the present invention, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0046] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; "connection" can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0047] See also Figure 1 The present invention provides a biomass pyrolysis polygeneration device with a gas circulation system, which includes a pretreatment furnace 1, a low-temperature pyrolysis furnace 2, a high-temperature carbonization furnace 3, a condenser 4 and a burner 5.

[0048] The pretreatment furnace 1 is a hollow tube arranged at an angle, the head end of the pretreatment furnace 1 is lower than the tail end, a feed port 11 is provided at the top of the head end of the pretreatment furnace 1, a circulating feeder 12 is provided inside the pretreatment furnace 1, and a plurality of feeding baffles 13 are distributed at intervals on the circulating feeder 12; a liquid discharge port 14 is provided at the bottom of the head end of the pretreatment furnace 1, and a waste heat flue gas recovery port is also provided at the head end of the pretreatment furnace 1. The raw materials enter from the head end of the pretreatment furnace 1, and under the gravity of the raw materials and the pushing action of the feeding baffle 13, the full contact between the raw materials and the hot gas is enhanced, the pretreatment effect is improved, and the subsequent pyrolysis process is made more uniform and efficient.

[0049] Among them, the pretreatment furnace 1 can be preferably a hollow square tube. The circulating feeder 12 is preferably a conveyor belt, which is supported by a pair of rollers rotatably installed on the side wall of the pretreatment furnace 1. When the circulating feeder 12 rotates clockwise, the upper side of the circulating feeder 12 moves from the head end to the end of the pretreatment furnace 1. The conveyor belt feeder can smoothly convey the raw materials, avoiding the material stirring and compression caused by the screw feeder, ensuring that the raw materials remain loose when in contact with hot air, thereby improving the dehydration effect. Moreover, the feeding baffle 13 is arranged on the conveyor belt, and the raw materials can be evenly conveyed in layers, so that each layer of raw materials can be dehydrated, thereby improving the pretreatment effect.

[0050] The low-temperature pyrolysis furnace 2 is a hollow tube arranged obliquely, the end of the low-temperature pyrolysis furnace 2 is lower than the head end, and the end of the pretreatment furnace 1 is connected to and connected with the head end of the low-temperature pyrolysis furnace 2; a pyrolysis screw feeder 21 is arranged inside the low-temperature pyrolysis furnace 2, a pyrolysis gas outlet 22 is arranged at the top of the end of the low-temperature pyrolysis furnace 2, and a pyrolysis charcoal outlet 23 is arranged at the bottom of the end of the low-temperature pyrolysis furnace 2. The end of the pyrolysis screw feeder 21 is stably supported for rotation by a double bearing structure.

[0051] The high-temperature carbonization furnace 3 is a horizontally arranged hollow tube, a carbonization screw feeder 31 is arranged inside the high-temperature carbonization furnace 3, the pyrolytic carbon outlet 23 is connected to the head end of the high-temperature carbonization furnace 3, an activated carbon outlet 32 ​​is arranged at the bottom of the end of the high-temperature carbonization furnace 3, a waste heat flue gas outlet 33 is arranged at the end of the high-temperature carbonization furnace 3, and the waste heat flue gas outlet 33 is connected to the waste heat flue gas recovery port.

[0052] Among them, in a preferred embodiment, the low-temperature pyrolysis furnace 2 and the high-temperature carbonization furnace 3 are both hollow tubes with a D-shaped cross-section, which include an arc wall and a plurality of flat walls (specifically, three flat walls form a square tube with a notch on one side), and the arc wall is connected to the notch of the square tube to form a hollow tube with a D-shaped cross-section. After installation, the flat wall is located at the top, and a smoke exhaust channel is formed between the flat wall and the corresponding pyrolysis screw feeder 21 or the carbonization screw feeder 31. Among them, the pyrolysis gas outlet 22 and the waste heat flue gas outlet 33 are respectively connected to the corresponding smoke exhaust channels. The screw feeder is located in the corresponding arc wall, and there is an independent space extended by the flat wall above the screw feeder. The large amount of flue gas generated by pyrolysis will not accumulate and stay, thereby reducing the possibility of coking and blockage, and at the same time reducing the secondary reaction of the pyrolysis gas.

[0053] The present invention docks the pretreatment furnace 1 and the low-temperature pyrolysis furnace 2, and then cooperates with the horizontally arranged high-temperature carbonization furnace 3 to form a triangular structure, which has the following advantages: First, the head end of the pretreatment furnace 1 is lower than the tail end, which can give full play to the gravity of the raw materials and the pushing effect of the feeding baffle 13, which is conducive to the full contact between the raw materials and the hot gas. Secondly, the tail end of the low-temperature pyrolysis furnace 2 is lower than the head end and is tilted. The gravity is used to make the raw materials slide down naturally, which reduces the dependence on mechanical conveying equipment and reduces energy consumption. Thirdly, the raw materials go through the pretreatment, pyrolysis and carbonization stages in sequence, which helps to better control the temperature and reaction time of each stage, and can also maximize the use of waste heat, improve thermal efficiency, and at the same time reduce the floor space of the equipment and improve space utilization.

[0054] In the present invention, the inlet of the condenser 4 is connected to the pyrolysis gas outlet 22, and the condenser 4 is also provided with a liquid product outlet 41; the inlet of the burner 5 is connected to the outlet of the condenser 4, and the outlet of the burner 5 is connected to the head end of the high-temperature carbonization furnace 3. The pyrolysis gas enters the condenser 4, and the separation and condensation treatment can obtain a liquid product rich in high-value products and a non-condensable high calorific value gas. The non-condensable high calorific value gas enters the burner 5 for combustion to obtain a high-temperature flue gas rich in carbon dioxide. The high-temperature flue gas rich in carbon dioxide obtained by the combustion of the pyrolysis gas can provide heat and an activator for the carbonization process.

[0055] The present invention couples pretreatment, low-temperature pyrolysis and high-temperature carbonization in one device, utilizes the waste heat generated in the high-temperature carbonization process to provide the required heat for the pretreatment stage, effectively saves energy consumption, utilizes the high-temperature flue gas rich in carbon dioxide obtained by burning pyrolysis gas to provide heat and activator for the carbonization process, and effectively improves energy utilization efficiency. The biomass raw material first enters the pretreatment furnace 1, and the initial pretreatment of the raw material is achieved through the extrusion effect of the feed baffle 13 on the circulating feeder 12 and the heat provided by the waste heat flue gas. After removing moisture, it enters the low-temperature pyrolysis furnace 2 for pyrolysis reaction to generate pyrolysis gas and pyrolysis char. The pyrolysis gas enters the condenser 4 for separation and condensation to obtain liquid products with low moisture content and low oxygen content, as well as non-condensable high calorific value gas. The non-condensable high calorific value gas enters the burner 5 for combustion to obtain carbon dioxide-rich high-temperature flue gas. The carbon dioxide-rich high-temperature flue gas and the pyrolysis char enter the high-temperature carbonization furnace 3 together. Under the physical activation of the carbon dioxide-rich high-temperature flue gas, it is further carbonized into a pore structure mainly composed of micropores or mesopores, with a larger specific surface area, and more stable and adsorption capacity. At the same time, the waste heat is recycled to the pretreatment process to form a multi-product system that jointly generates a variety of high-value products, thereby improving the utilization rate of waste heat and the comprehensive utilization efficiency of energy, as well as the utilization efficiency of biomass resources. In summary, by coupling pretreatment, low-temperature pyrolysis and high-temperature carbonization into one system, pretreatment is used to improve the quality of low-temperature pyrolysis and high-temperature carbonization products, and the waste heat generated by the high-temperature carbonization process is used to provide the required heat for pretreatment, efficient co-production of pyrolysis and carbonization is achieved, which has the advantages of efficient energy utilization, energy saving and environmental protection.

[0056] In a preferred embodiment, a plurality of feed baffles 13 located on the same side of the circulating feeder 12 are parallel to each other and evenly spaced, and the interval between adjacent feed baffles 13 can be preferably 20-50 mm; the angle between the circulating feeder 12 and the feed baffle 13 can be preferably 45°-135°; the gap between each edge (two side edges and one top edge) of the feed baffle 13 and the inner wall surface corresponding to the pretreatment furnace 1 can be preferably 1-3 mm. The angle formed by the axis of the pretreatment furnace 1 and the axis of the low-temperature pyrolysis furnace 2 can be preferably 90°-120°.

[0057] In addition, a material blocking baffle 24 protruding upward is provided at the bottom of the joint between the end of the pretreatment furnace 1 and the head end of the low-temperature pyrolysis furnace 2; the material blocking baffle 24 is a hard plate (made of rigid material), and the feeding baffle 13 is a soft plate (made of flexible material and elastically deformable), and the material blocking baffle 24 is arranged in parallel with the feeding baffle 13; the gap between the material blocking baffle 24 and the wall of the circulating feeder 12 can preferably be 1 to 3 mm. When the circulating feeder 12 rotates, if the feeding baffle 13 hits the material blocking baffle 24, the feeding baffle 13 will be squeezed to elastic deformation and can pass through the gap between the material blocking baffle 24 and the circulating feeder 12, and the feeding baffle 13 can restore its original shape after passing through the gap. Moreover, since the material blocking baffle 24 is located at the bottom of the docking point, and the raw materials are transported from the head end to the end on the upper side of the circulating loader 12, when the raw materials reach the end of the pretreatment furnace 1, they will be blocked by the material blocking baffle 24 and can only enter the head end of the low-temperature pyrolysis furnace 2, and can no longer return to the head end of the pretreatment furnace 1. The material blocking baffle 24 greatly improves the efficiency of raw material transportation.

[0058] In addition, in a preferred embodiment, the outer diameter of the spiral blade of the pyrolysis screw feeder 21 is 0.5 to 0.8 times the outer diameter of the spiral blade of the carbonization screw feeder 31; the pitch of the spiral blade of the pyrolysis screw feeder 21 is 2 to 5 times the pitch of the spiral blade of the carbonization screw feeder 31. The larger pitch of the pyrolysis screw feeder 21 helps to reduce the residence time of the material in the equipment and avoid excessive reaction or secondary reaction of the material during the pyrolysis process. The smaller pitch of the carbonization screw feeder 31 can extend the residence time of the material in the equipment. This is particularly important for the activation process of activated carbon. Extending the residence time can enable the material to fully contact the reaction atmosphere, improve the carbonization and activation efficiency, and thus obtain a more active activated carbon product. At the same time, in order to maintain the smoothness of the material flow in the equipment and avoid material accumulation, the outer diameter of the spiral blade needs to be appropriately adjusted. When the pitch increases, the outer diameter is smaller, and when the pitch decreases, the outer diameter is larger to ensure fast and uniform material delivery.

[0059] Furthermore, the present invention also provides a pyrolysis polygeneration method, which is implemented based on the above-mentioned biomass pyrolysis polygeneration device with a gas circulation system, and comprises:

[0060] S1, the circulating feeder 12 rotates clockwise, driving the feeding baffle 13 to move, and the pyrolysis screw feeder 21 and the carbonization screw feeder 31 rotate at a set speed driven by the corresponding motors; at the same time, the low-temperature pyrolysis furnace 2 and the high-temperature carbonization furnace 3 are heated to the set temperature respectively;

[0061] S2, raw materials are added from the feed port 11, and the feed baffle 13 drives the raw materials to move in the pretreatment furnace 1. Under the baking of the pretreatment furnace 1 and the extrusion effect of the feed baffle 13, the raw materials are free of excess moisture, and the pretreated raw materials (under the combined effect of low-temperature baking in the pretreatment furnace 1 and the extrusion of the flexible feed baffle 13, the pretreatment effect is enhanced, and after the excess moisture is evaporated, the rigid material blocking baffle 24 is blocked) are sent to the low-temperature pyrolysis furnace 2;

[0062] S3, the raw material is heated in the low-temperature pyrolysis furnace 2 and undergoes a pyrolysis reaction to produce pyrolytic carbon and pyrolytic gas; the pyrolytic gas enters the condenser 4 through the pyrolytic gas outlet 22, and the pyrolytic oil with low water content and low oxygen content obtained after condensation and separation is discharged from the liquid product outlet 41, and the remaining non-condensable gas enters the burner 5 for combustion to generate high-temperature flue gas rich in carbon dioxide, and the pyrolytic carbon enters the high-temperature carbonization furnace 3 through the pyrolytic carbon outlet 23;

[0063] S4, the high-temperature flue gas rich in carbon dioxide generated by the burner 5 enters the high-temperature carbonization furnace 3, the pyrolytic carbon is further heated in the high-temperature carbonization furnace 3, and a carbonization reaction occurs under the physical activation of the high-temperature flue gas rich in carbon dioxide, generating waste heat flue gas and activated carbon; the activated carbon is discharged through the activated carbon outlet 32 ​​and collected, and the waste heat flue gas is sent back to the pretreatment furnace 1 through the waste heat flue gas outlet 33.

[0064] Among them, the temperature of the pretreatment furnace 1 is provided by the waste heat flue gas from the high-temperature carbonization furnace 3, and the temperature of the pretreatment furnace 1 is 150-200°C; the temperature of the low-temperature pyrolysis furnace 2 is electrically heated, and the temperature of the low-temperature pyrolysis furnace 2 is 400-600°C, and the temperature of the high-temperature carbonization furnace 3 is provided by the high-temperature flue gas rich in carbon dioxide from the burner 5, and the temperature of the high-temperature carbonization furnace 3 is 800-1000°C; the temperature of the condenser 4 is 0-20°C.

[0065] The following is a detailed description of a method for pyrolysis polygeneration using a biomass pyrolysis polygeneration device with a gas circulation system through specific embodiments, wherein each embodiment uses a device with a substantially same structure.

[0066] Example 1

[0067] The inner cross-section of the pretreatment furnace 1 is a 300mm×300mm square and a length of 800mm; the circulating feeder 12 is placed in the pretreatment furnace 1, and the feeding baffles 13 are evenly distributed. The interval between adjacent feeding baffles 13 is 20mm, the angle between the feeding baffle 13 and the circulating feeder 12 is 45°, and the gap between the feeding baffle 13 and the inner wall of the pretreatment furnace 1 is 2mm; the inner diameter of the inner cross-section of the arc wall of the low-temperature pyrolysis furnace 2 is 300mm, the outer diameter is 420mm, and the length is 100 0mm; the low-temperature pyrolysis furnace 2 is connected to the pretreatment furnace 1 at an angle of 90°, and a material blocking baffle 24 is arranged in the middle; the shaft diameter of the pyrolysis screw feeder 21 is 100mm, the outer diameter of the spiral blade is 296m, and the pitch is 20mm; the inner diameter of the inner section of the arc wall of the high-temperature carbonization furnace 3 is 400mm, the outer diameter is 560mm, and the length is 1200mm; the shaft diameter of the carbonization screw feeder 31 is 150mm, the outer diameter of the spiral blade is 396mm, and the pitch is 5mm.

[0068] Bagasse with a moisture content of 30.8% is used as a raw material and fed into the pretreatment furnace 1. The average temperature in the furnace is 150°C, and the rotation speed of the circulating feeder 12 is 1r / min. After baking pretreatment, the moisture content drops below 6.5%. Under the interaction of the feeding baffle 13 and the material blocking baffle 24, the pretreated raw material is fed into the low-temperature pyrolysis furnace 2 with a temperature set to 400°C. The rotation speed of the pyrolysis screw feeder 21 is 10r / min. Under the promotion of the pyrolysis screw feeder 21, the raw material is rapidly heated and a pyrolysis reaction occurs. The pyrolysis gas enters the condenser 4 and is rapidly separated and condensed. The liquid phase yield is 39.8wt%, the water content of the bio-oil is 30.8%, the oxygen content is 40.1%, and the remaining incondensable gas (calorific value is 11.5MJ / Nm 3 ) enters the burner 5 for combustion to obtain carbon dioxide-rich high-temperature flue gas, in which carbon dioxide accounts for 90.9%; the carbon dioxide-rich high-temperature flue gas enters the high-temperature carbonization furnace 3 from the outlet of the burner 5, and the pyrolytic carbon enters the high-temperature carbonization furnace 3 with a temperature set to 900°C through the pyrolytic carbon outlet 23. The speed of the carbonization screw feeder 31 is 5r / min. Under the push of the carbonization screw feeder 31, the raw material is further heated, and activated carbon is formed under the activation of the carbon dioxide-rich high-temperature flue gas from the burner 5. The waste heat flue gas enters the pretreatment furnace 1 through the waste heat flue gas outlet 33 to provide the heat required for pretreatment.

[0069] The final specific surface area is 946.7 cm 2 / g, and the activated carbon mainly composed of micropores with an average pore size of 9.8nm, realizes the multi-product utilization of pyrolysis of biomass waste.

[0070] Example 2

[0071] The difference between this embodiment and the embodiment 1 is that the distribution of the circulating feeder 12 and the structure of the connection with the pretreatment furnace 1 and the low-temperature pyrolysis furnace 2 are changed. The feeding baffles 13 are evenly distributed on the circulating feeder 12, the interval between adjacent feeding baffles 13 is 15 mm, the angle between the feeding baffles 13 and the circulating feeder 12 is 60°, the low-temperature pyrolysis furnace 2 is connected to the pretreatment furnace 1 through the middle, the angle is 120°, and a material blocking baffle 24 is arranged in the middle.

[0072] Sawdust with a moisture content of 25.4% is used as a raw material and is fed into the pretreatment furnace 1. The average temperature in the furnace is 150°C, and the rotation speed of the circulating feeder 12 is 0.5r / min. After baking pretreatment, the moisture content drops below 8.4%. Under the interaction of the feeding baffle 13 and the material blocking baffle 24, the pretreated raw material is fed into the low-temperature pyrolysis furnace 2 with a temperature set at 350°C. The rotation speed of the pyrolysis screw feeder 21 is 15r / min. Under the promotion of the pyrolysis screw feeder 21, the raw material is rapidly heated and a pyrolysis reaction occurs. The pyrolysis gas enters the condenser 4 and is rapidly separated and condensed. The liquid phase yield is 31.9wt%, the water content of the bio-oil is 32.8%, the oxygen content is 39.7%, and the remaining incondensable gas (calorific value is 10.3MJ / Nm 3 ) enters the burner 5 for combustion, and obtains carbon dioxide-rich high-temperature flue gas, in which carbon dioxide accounts for 92.2%; the carbon dioxide-rich high-temperature flue gas enters the high-temperature carbonization furnace 3 from the outlet of the burner 5, and the pyrolytic carbon enters the high-temperature carbonization furnace 3 with a temperature set to 1000°C through the pyrolytic carbon outlet 23. The rotation speed of the carbonization screw feeder 31 is 3r / min. Under the push of the carbonization screw feeder 31, the raw material is further heated, and activated carbon is formed under the activation of the carbon dioxide-rich high-temperature flue gas from the burner 5. The waste heat flue gas enters the pretreatment furnace 1 through the waste heat flue gas outlet 33 to provide the heat required for pretreatment.

[0073] The final specific surface area is 1255.8cm 2 / g, and the activated carbon mainly composed of micropores with an average pore size of 6.5nm, realizes the multi-product utilization of pyrolysis of biomass waste.

[0074] Example 3

[0075] The present embodiment differs from the first embodiment in that the feeding baffles 13 are evenly distributed on the circulating feeder 12, and the interval between adjacent feeding baffles 13 is 30 mm.

[0076] Poplar wood with a moisture content of 28.7% is used as a raw material and is fed into the pretreatment furnace 1. The average temperature in the furnace is 200°C, and the rotation speed of the circulating feeder 12 is 0.6r / min. After baking pretreatment, the moisture content drops below 6.1%. Under the interaction of the feeding baffle 13 and the material blocking baffle 24, the pretreated raw material is fed into the low-temperature pyrolysis furnace 2 with a temperature set to 580°C. The rotation speed of the pyrolysis screw feeder 21 is 17r / min. Under the promotion of the pyrolysis screw feeder 21, the raw material is rapidly heated and a pyrolysis reaction occurs. The pyrolysis gas enters the condenser 4 and is rapidly separated and condensed. The liquid phase yield is 30.1wt%, the water content of the bio-oil is 30.8%, the oxygen content is 39.4%, and the remaining incondensable gas (calorific value is 12.1MJ / Nm 3 ) enters the burner 5 for combustion to obtain carbon dioxide-rich high-temperature flue gas, in which carbon dioxide accounts for 88.5%; the carbon dioxide-rich high-temperature flue gas enters the high-temperature carbonization furnace 3 from the outlet of the burner 5, and the pyrolytic char enters the high-temperature carbonization furnace 3 with a temperature set to 700°C through the pyrolytic char outlet 23. The speed of the carbonization screw feeder 31 is 2.5r / min. Under the push of the carbonization screw feeder 31, the raw material is further heated up, and activated carbon is formed under the activation of the carbon dioxide-rich high-temperature flue gas from the burner 5. The waste heat flue gas enters the pretreatment furnace 1 through the waste heat flue gas outlet 33 to provide the heat required for pretreatment.

[0077] The final specific surface area is 523.3 cm 2 / g, and the activated carbon mainly composed of mesopores with an average pore size of 22.5nm, realizes the multi-product utilization of pyrolysis of biomass waste.

[0078] Example 4

[0079] The present embodiment differs from the first embodiment in that the angle between the feed baffle 13 and the circulating loader 12 is 135°, the low-temperature pyrolysis furnace 2 is connected to the pretreatment furnace 1 through a central passage at an angle of 110°, and a material blocking baffle 24 is provided in the middle.

[0080] Bagasse with a moisture content of 15.9% is used as a raw material and fed into the pretreatment furnace 1. The average temperature in the furnace is 180°C, and the rotation speed of the circulating feeder 12 is 0.4r / min. After baking pretreatment, the moisture content drops below 4.1%. Under the interaction of the feeding baffle 13 and the material blocking baffle 24, the pretreated raw material is fed into the low-temperature pyrolysis furnace 2 with a temperature set to 550°C. The rotation speed of the pyrolysis screw feeder 21 is 19r / min. Under the promotion of the pyrolysis screw feeder 21, the raw material is rapidly heated and a pyrolysis reaction occurs. The pyrolysis gas enters the condenser 4 and is rapidly separated and condensed. The liquid phase yield is 38.8wt%, the water content of the bio-oil is 32.1%, the oxygen content is 37.7%, and the remaining incondensable gas (calorific value is 9.9MJ / Nm 3) enters the burner 5 for combustion to obtain carbon dioxide-rich high-temperature flue gas, in which carbon dioxide accounts for 91.2%; the carbon dioxide-rich high-temperature flue gas enters the high-temperature carbonization furnace 3 from the outlet of the burner 5, and the pyrolytic char enters the high-temperature carbonization furnace 3 with a temperature set to 850°C through the pyrolytic char outlet 23. The speed of the carbonization screw feeder 31 is 3r / min. Under the push of the carbonization screw feeder 31, the raw material is further heated up, and activated carbon is formed under the activation of the carbon dioxide-rich high-temperature flue gas from the burner 5. The waste heat flue gas enters the pretreatment furnace 1 through the waste heat flue gas outlet 33 to provide the heat required for pretreatment.

[0081] The final specific surface area is 688.0 cm 2 / g, and the activated carbon mainly composed of mesopores with an average pore size of 19.5nm, realizes the multi-product utilization of pyrolysis of biomass waste.

[0082] It should be understood that the above description of the specific embodiments of the present invention is only for illustrating the technical route and features of the present invention, and its purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly, but the present invention is not limited to the above specific implementation methods. Any changes or modifications made within the scope of the claims of the present invention should be included in the protection scope of the present invention.

Claims

1. A biomass pyrolysis polygeneration device with a gas circulation system, characterized in that: include: A pretreatment furnace (1), wherein the pretreatment furnace (1) is a hollow tube arranged at an angle, the head end of the pretreatment furnace (1) is lower than the tail end, a feed port (11) is provided at the top of the head end of the pretreatment furnace (1), a circulating feeder (12) is provided inside the pretreatment furnace (1), and a plurality of feed baffles (13) are spaced apart on the circulating feeder (12); a liquid discharge port (14) is provided at the bottom of the head end of the pretreatment furnace (1), and a waste heat flue gas recovery port is also provided at the head end of the pretreatment furnace (1); A low-temperature pyrolysis furnace (2), wherein the low-temperature pyrolysis furnace (2) is a hollow tube arranged obliquely, the end of the low-temperature pyrolysis furnace (2) is lower than the head end, and the end of the pretreatment furnace (1) is butt-jointed with and connected to the head end of the low-temperature pyrolysis furnace (2); a pyrolysis screw feeder (21) is arranged inside the low-temperature pyrolysis furnace (2), a pyrolysis gas outlet (22) is arranged at the top of the end of the low-temperature pyrolysis furnace (2), and a pyrolysis charcoal outlet (23) is arranged at the bottom of the end of the low-temperature pyrolysis furnace (2); A high-temperature carbonization furnace (3), wherein the high-temperature carbonization furnace (3) is a horizontally arranged hollow tube, and a carbonization screw feeder (31) is arranged inside the high-temperature carbonization furnace (3); the pyrolytic carbon outlet (23) is connected to the head end of the high-temperature carbonization furnace (3), an activated carbon outlet (32) is arranged at the bottom of the end of the high-temperature carbonization furnace (3), and a waste heat flue gas outlet (33) is arranged at the end of the high-temperature carbonization furnace (3), and the waste heat flue gas outlet (33) is connected to the waste heat flue gas recovery port; A condenser (4), wherein the inlet of the condenser (4) is connected to the pyrolysis gas outlet (22), and the condenser (4) is also provided with a liquid product outlet (41); A burner (5), wherein the inlet of the burner (5) is connected to the outlet of the condenser (4), and the outlet of the burner (5) is connected to the head end of the high-temperature carbonization furnace (3).

2. The biomass pyrolysis polygeneration device with a gas circulation system according to claim 1, characterized in that: The pretreatment furnace (1) is a hollow square tube; The low-temperature pyrolysis furnace (2) and the high-temperature carbonization furnace (3) are both hollow tubes with a D-shaped cross-section. The tops of the low-temperature pyrolysis furnace (2) and the high-temperature carbonization furnace (3) are both flat walls, and a smoke exhaust channel is formed between the flat wall and the corresponding pyrolysis screw feeder (21) or the carbonization screw feeder (31).

3. The biomass pyrolysis polygeneration device with a gas circulation system according to claim 1, characterized in that: The angle formed by the axis of the pretreatment furnace (1) and the axis of the low-temperature pyrolysis furnace (2) is 90° to 120°.

4. The biomass pyrolysis polygeneration device with a gas circulation system according to claim 1, characterized in that: A material blocking baffle (24) protruding upward is provided at the bottom of the joint between the end of the pretreatment furnace (1) and the head end of the low-temperature pyrolysis furnace (2); the feed baffle (13) is a soft plate, and the material blocking baffle (24) is arranged parallel to the feed baffle (13); the gap between the material blocking baffle (24) and the wall of the circulation feeder (12) is 1 to 3 mm.

5. The biomass pyrolysis polygeneration device with a gas circulation system according to claim 1, characterized in that: The interval between adjacent feeding baffles (13) is 20 to 50 mm; the angle between the circulating feeder (12) and the feeding baffle (13) is 45° to 135°; and the gap between the feeding baffle (13) and the inner wall of the pretreatment furnace (1) is 1 to 3 mm.

6. The biomass pyrolysis polygeneration device with a gas circulation system according to claim 1, characterized in that: The outer diameter of the spiral blade of the pyrolysis screw feeder (21) is 0.5 to 0.8 times the outer diameter of the spiral blade of the carbonization screw feeder (31); and the pitch of the spiral blade of the pyrolysis screw feeder (21) is 2N5 times the pitch of the spiral blade of the carbonization screw feeder (31).

7. The biomass pyrolysis polygeneration device with a gas circulation system according to claim 1, characterized in that: The circulating feeder (12) is a conveyor belt.

8. A pyrolysis polygeneration method, which is implemented based on the biomass pyrolysis polygeneration device with a gas circulation system according to any one of claims 1 to 7, characterized in that: The pyrolysis polygeneration method comprises: S1, the circulating feeder (12) rotates clockwise, driving the feeding baffle (13) to move, and the pyrolysis screw feeder (21) and the carbonization screw feeder (31) rotate at a set speed; at the same time, the low-temperature pyrolysis furnace (2) and the high-temperature carbonization furnace (3) are heated to the set temperature respectively; S2, raw materials are added from the feed port (11), the feed baffle (13) drives the raw materials to move in the pretreatment furnace (1), and under the baking effect of the pretreatment furnace (1) and the squeezing effect of the feed baffle (13), the raw materials are fed into the low-temperature pyrolysis furnace (2) after excess moisture is removed from the raw materials; S3, the raw material is heated in the low-temperature pyrolysis furnace (2) and undergoes a pyrolysis reaction to produce pyrolysis char and pyrolysis gas; the pyrolysis gas enters the condenser (4) through the pyrolysis gas outlet (22), the pyrolysis oil obtained after condensation and separation is discharged from the liquid product outlet (41), and the remaining incondensable gas enters the burner (5) for combustion to generate carbon dioxide-rich high-temperature flue gas, and the carbon dioxide-rich high-temperature flue gas and the pyrolysis char enter the high-temperature carbonization furnace (3) together; S4. The high-temperature flue gas rich in carbon dioxide generated by the burner (5) enters the high-temperature carbonization furnace (3), and the pyrolytic carbon is further heated in the high-temperature carbonization furnace (3). A carbonization reaction occurs under the physical activation of the high-temperature flue gas rich in carbon dioxide, thereby generating waste heat flue gas and activated carbon; the activated carbon is discharged through the activated carbon outlet (32) and collected, and the waste heat flue gas is sent back to the pretreatment furnace (1) through the waste heat flue gas outlet (33).

9. The pyrolysis polygeneration method according to claim 8, characterized in that: The temperature of the pretreatment furnace (1) is provided by the waste heat flue gas from the high-temperature carbonization furnace (3), and the temperature of the pretreatment furnace (1) is 150-200°C; the temperature of the low-temperature pyrolysis furnace (2) is electrically heated, and the temperature of the low-temperature pyrolysis furnace (2) is 400-600°C; the temperature of the high-temperature carbonization furnace (3) is provided by the high-temperature flue gas rich in carbon dioxide from the burner (5), and the temperature of the high-temperature carbonization furnace (3) is 800-1000°C; the temperature of the condenser (4) is 0-20°C.

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