A system and method for preparing catalysts by internal circulation enhanced jet pyrolysis
By enhancing the jet-driven pyrolysis system through internal circulation and improving the reactor structure and process parameters, the problems of poor mixing, uneven temperature, and low efficiency in catalyst preparation were solved, achieving efficient preparation of high-quality iron-carbon catalysts and improving mass and heat transfer efficiency and product quality.
Patent Information
- Application Number
- CN202311430847.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-10-31
- Publication Date
- 2025-10-28
- Estimated Expiration
- 2043-10-31
AI Technical Summary
In the existing technology, there are problems such as poor two-phase mixing, uneven temperature, unstable product quality, low system efficiency and serious pollution in the catalyst preparation process. In particular, when preparing iron-carbon catalysts, mechanical stirring causes serious catalyst damage and makes it difficult to control the particle size.
An internal circulation enhanced jet pyrolysis system is adopted. By improving the reactor structure, adjusting the iron-carbon ratio, configuring internal and external circulation loops and heating jackets, and combining multi-stage heating and multi-stage reaction, the internal circulation jet bed utilizes the internal and external circulation and upper and lower circulation modes, combined with the conveying and extrusion of the screw unloader and the solid material sealing of the material sealing unit, to achieve multi-stage heating and multi-stage reaction, promote gas-solid and solid-solid mixing, extend the residence time of solid particles, and improve temperature uniformity and product quality.
This method enables the efficient preparation of high-quality carbon-based catalysts, improves mass and heat transfer efficiency and reaction rate, enhances the pore distribution structure and adsorption performance of the product, significantly improves system efficiency, and avoids the problems of catalyst breakage and particle size control.
Smart Images
Figure CN117244485B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a system and method for preparing catalysts (such as iron-carbon catalysts) by internal circulation enhanced jet pyrolysis of metal-containing (such as iron) solid waste. Background Technology
[0002] Current research on iron-containing solid waste treatment mainly focuses on incineration, pyrolysis, and gasification. Iron resource utilization is low. Iron-carbon catalysts are generally prepared using fossil fuel-based and biomass-based carbon-based materials, employing impregnation, hydrothermal, and sol-gel methods. Unit operations are mostly stirred tank reactors, but due to mechanical agitation, catalyst damage is severe, and particle size control is difficult. Fluidized bed reactors offer uniform and controllable temperature, compact structure, and low energy consumption, providing significant advantages in two-phase and three-phase mixing. Internal circulation sputtered beds, a special type of fluidized bed, not only promote multiphase turbulence and mixing, improve mass and heat transfer efficiency and reaction rate, and increase system efficiency, but also enable product diversification and precise particle size control, achieving multi-product co-production. They can be used to prepare various adsorbents, catalysts, and functional carbon materials, possessing significant technological advantages and broad application prospects. Summary of the Invention
[0003] The purpose of this invention is to solve the problems of poor two-phase mixing, uneven temperature, unstable product quality, low system efficiency, and serious pollution in the traditional catalyst preparation process. By improving additives and reactor structure and optimizing various process parameters, multi-stage heating and multi-stage reaction are achieved in one reactor, which improves the uniformity of bed temperature and the stability of product quality, enhances the pore distribution structure and adsorption performance of carbon-based materials, and efficiently prepares iron-carbon catalysts. By controlling process parameters, product distribution is improved.
[0004] The technical solution to achieve the objective of this invention is: a system and method for preparing catalysts by internal circulation enhanced jet pyrolysis. The system includes, in sequence, a raw material feeding unit, an internal circulation jet bed pyrolysis unit, a screw unloader, a material sealing unit, a material circulation unit, a pyrolysis gas condenser, a pyrolysis gas purification unit, a circulating gas purification unit, and a solid product discharge unit. The raw material feeding unit includes, in sequence, a raw material conveyor, a locked hopper, a roller extruder, and a screw feeder. The screw feeder is connected to the internal circulation jet bed pyrolysis unit. The internal circulation jet bed pyrolysis unit is connected to the screw unloader, a combustion unit, and two cyclone separators. Cyclone separator one is connected to the internal circulation jet bed pyrolysis unit, the screw unloader, and the pyrolysis gas condenser. The pyrolysis gas condenser is connected to the pyrolysis gas purification unit. The pyrolysis gas purification unit... The system is connected to the combustion unit, the steam generation unit, and the internal circulation jetting bed pyrolysis unit. The steam generation unit is connected to the screw feeder, the screw feeder is connected to the roller extruder and the internal circulation jetting bed pyrolysis unit, the cyclone separator II is connected to the circulating gas purification unit and the internal circulation jetting bed pyrolysis unit, the screw unloader is connected to the material sealing unit, and the material sealing unit is connected to the material circulation unit. The solid product discharge unit includes cyclone separator III, a high-level solid product collection tank, cyclone separator IV, and a low-level solid product collection tank. The material circulation unit is connected to cyclone separator II, cyclone separator III, and cyclone separator IV. Cyclone separator III is connected to the high-level solid product collection tank and the circulating gas purification unit, and cyclone separator IV is connected to the low-level solid product collection tank and the circulating gas purification unit.
[0005] The aforementioned system for preparing catalysts using internal circulation enhanced jet pyrolysis comprises an internal circulation jet bed pyrolysis unit including a settling section, a conical section, an internal circulation cylinder, and a heating section. The internal circulation jet bed pyrolysis unit adopts a vertical structure combining internal and external circulation, upper and lower circulation, and multi-stage heating. The internal circulation cylinder is located at the bottom of the internal circulation jet bed pyrolysis unit and is centrally symmetrical. The flue gas from the combustion unit enters the bottom of the internal circulation jet bed pyrolysis unit and flows upward through the internal circulation cylinder. Solid particles are jetted upward along the internal circulation cylinder with the flue gas and are ejected from the top of the internal circulation cylinder. The ejected solids fall to the bottom along the channel between the internal circulation cylinder and the inner wall of the internal circulation jet bed pyrolysis unit. A portion of the falling solid particles recirculates back into the internal circulation cylinder, achieving an efficient combination of upper and lower circulation and internal and external circulation. Another portion of the solid particles are discharged to the screw unloader. After gas-solid separation by the cyclone separator, the solid particles enter the bottom of the internal circulation jet bed pyrolysis unit through a pipe and are placed outside the internal circulation cylinder. The heating section is located outside the conical section and uses microwave irradiation, electromagnetic induction heating, or electric heating.
[0006] The aforementioned system for preparing catalysts by internal circulation enhanced jet pyrolysis employs an inclined slope mechanism for the material sealing unit. Inside the material sealing unit, baffles are arranged, with a certain gap between the baffles and the slope below to allow solid particles to pass through. The accumulation of solid particles forms a material seal to prevent cross-contamination.
[0007] The aforementioned system for preparing catalysts via enhanced internal circulation jet pyrolysis involves a screw feeder connected to an internal circulation jet bed pyrolysis unit and a cyclone separator via a pipeline. Solid particles flow from the bottom of the internal circulation jet bed pyrolysis unit and enter the screw feeder. After gas-solid separation in the cyclone separator, the solid particles flow downwards into the screw feeder. The screw pitch of the screw feeder gradually decreases, with the minimum pitch being 50% of the screw blade diameter, thus forming a conveying and extrusion-type material seal to prevent cross-venting at both ends. The solid particles conveyed by the screw feeder enter the material seal unit through the outlet and are located inside the material seal unit's partition, thus accumulating to form a material seal. The combination of screw extrusion and solid particle accumulation material seal promotes the isolation between the internal circulation jet bed pyrolysis unit and the material circulation unit, preventing cross-venting at both ends and improving system stability and safety.
[0008] In the aforementioned system for preparing catalysts by internal circulation enhanced jet pyrolysis, the steam generated by the steam generation unit enters the bottom of the settling section of the internal circulation jet pyrolysis unit from a tangential position, thereby forming a swirling steam inlet mode, which promotes particle settling and gas-solid contact, prolongs the solid residence time, and improves the pyrolysis depth, thus improving system efficiency. The steam inlet is located on the settling section side at the junction of the settling section and the conical section.
[0009] In the aforementioned system for preparing catalysts by enhanced internal circulation jet pyrolysis, the hot flue gas from the steam generation unit is connected to the jacket of the screw feeder through a pipeline, thereby indirectly heating the screw feeder with the hot flue gas. The hot flue gas exiting the jacket of the screw feeder enters the hollow shaft of the roller extruder, indirectly heating the raw materials inside the roller extruder, thus improving the system efficiency.
[0010] The present invention has the following positive effects: (1) The system of the present invention, by improving the reactor structure, adjusting the iron-carbon ratio, arranging the internal and external circulation loops, configuring the heating jacket, and developing the thermal integration technology that combines indirect and direct heating, has constructed a system with multi-stage heating, multi-stage reaction, internal circulation turbulence and internal and external circulation, to prepare high-quality carbon-based products and realize the multi-product production of gas and solid products; (2) The internal circulation cylinder of the internal circulation jet bed pyrolysis unit forms a multi-element mixing mode of internal and external circulation and upper and lower circulation of solid particles, which strengthens gas-solid mixing, promotes gas-solid-solid heat and mass transfer, and improves reaction efficiency. The heating section is located outside the conical section and adopts microwave irradiation, electromagnetic induction heating or electric heating to form a heating mode that combines direct heating of flue gas and external heating of the heater, which improves temperature uniformity, improves gas-solid mixing, and improves product quality; (3) Through the conveying and extrusion of the screw unloader and the solid material sealing of the material sealing unit, the internal circulation jet bed pyrolysis unit and the material circulation unit are realized. Effective isolation prevents cross-contamination between the two ends. The material circulation unit returns the solid particles to the internal circulation spray bed pyrolysis unit, forming an external large circulation of solid particles and coupling with the internal circulation of the internal circulation spray bed pyrolysis unit. This prolongs the residence time of solid particles, promotes gas-solid-solid-solid mixing turbulence, and improves the pyrolysis depth. (4) The steam from the steam generation unit enters the internal circulation spray bed pyrolysis unit tangentially. The steam inlet is located at the junction of the settling section and the conical section, close to the settling section side, forming a steam swirl steam inlet mode. This promotes gas-solid turbulence, prolongs the solid residence time, and improves the pyrolysis depth and gas-solid separation efficiency. (5) The hot flue gas generates steam through the steam generation unit. The hot flue gas stream enters the heating jacket of the screw feeder to indirectly heat the raw material inside the screw. Then, the hot flue gas enters the hollow shaft of the roller extruder to indirectly heat the raw material inside. This forms a high-efficiency thermal integration technology of direct and indirect heating of hot flue gas, which greatly improves the system efficiency. Attached Figure Description
[0011] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein...
[0012] Figure 1 This is a schematic diagram of the system and structure of the present invention;
[0013] in:
[0014] 1. Internal circulation jet bed pyrolysis unit; 2. Settling section; 3. Conical section; 4. Internal circulation cylinder; 5. Screw unloader; 6. Material sealing unit; 7. Material circulation unit; 8. Heating section; 9. Raw material conveyor; 10. Locking hopper; 11. Roller extruder; 12. Screw feeder; 13. Cyclone separator I; 14. Pyrolysis gas condenser; 15. Pyrolysis gas purification unit; 16. Combustion unit; 17. Steam generation unit; 18. Cyclone separator II; 19. Circulating gas purification unit; 20. Cyclone separator III; 21. High-level solid product collection tank; 22. Cyclone separator IV; 23. Low-level solid product collection tank. Detailed Implementation
[0015] (Example 1, see...) Figure 1 )
[0016] This embodiment includes a raw material feeding unit, an internal circulation jet-driven pyrolysis unit 1, a screw unloader 5, a material sealing unit 6, a material circulation unit 7, a pyrolysis gas condenser 14, a pyrolysis gas purification unit 15, a circulating gas purification unit 19, and a solid product discharging unit, all connected in sequence. The raw material feeding unit includes a raw material conveyor 9, a locked hopper 10, a roller extruder 11, and a screw feeder 12, all connected in sequence. The screw feeder 12 is connected to the internal circulation jet-driven pyrolysis unit 1. The internal circulation jet-driven pyrolysis unit 1 is connected to the screw unloader 5, a combustion unit 16, a cyclone separator 13, and a cyclone separator 18. The cyclone separator 13 is connected to the internal circulation jet-driven pyrolysis unit, the screw unloader 5, and the pyrolysis gas condenser 14. The pyrolysis gas condenser 14 is connected to the pyrolysis gas purification unit 15. The pyrolysis gas purification unit 15 is connected to the combustion unit 16. The combustion unit 16 is connected to steam... Steam generation unit 17 is connected to internal circulation jetting bed pyrolysis unit 1. Steam generation unit 17 is connected to the jacket of screw feeder 12. Screw feeder 12 is connected to roller extruder 11 and internal circulation jetting bed pyrolysis unit 1. Cyclone separator 2 18 is connected to circulating gas purification unit 19 and internal circulation jetting bed pyrolysis unit 1. Screw unloader 5 is connected to material sealing unit 6. Material sealing unit 6 is connected to material circulation unit 7. Solid product discharge unit includes cyclone separator 3, solid product high-level collection tank, cyclone separator 4 and solid product low-level collection tank. Material circulation unit 7 is connected to cyclone separator 2 18, cyclone separator 3 20 and cyclone separator 4 22. Cyclone separator 3 20 is connected to solid product high-level collection tank 21 and circulating gas purification unit 19. Cyclone separator 4 22 is connected to solid product low-level collection tank 23 and circulating gas purification unit 19.
[0017] Using iron-containing sludge (such as dyeing and printing sludge) as raw material, the pre-dried sludge is conveyed to the outside of the inner circulation cylinder 4 of the inner circulation sputtering bed pyrolysis unit 1 through the roller extruder 11 and screw feeder 12 of the raw material feeding unit. The heat source for sludge pre-drying is the waste heat of flue gas. The sludge entering the inner circulation sputtering bed pyrolysis unit 1 has a moisture content of less than 30%. The hot flue gas from the combustion unit 16 enters the bottom of the inner circulation cylinder 4 of the inner circulation sputtering bed pyrolysis unit 1. The flue gas and solid particles in the inner circulation cylinder 4 are ejected upward and fluidized. The solid particles are ejected from the top of the inner circulation cylinder 4 and fall into the annular channel between the inner circulation cylinder 4 and the inner wall of the inner circulation sputtering bed pyrolysis unit 1. The solid particles form a flow pattern of internal ejection, vertical circulation, and internal and external circulation, which promotes gas-solid and solid-solid mixing and improves mass transfer. In terms of heat transfer and reaction efficiency, the gas ejected from the top of the inner circulation cylinder 4 enters the settling section 2. After gas-solid separation by the cyclone separator 13, the solids flow into the screw unloader 5. The gas is then processed by the pyrolysis gas condenser 14 and the pyrolysis gas purification unit 15 before entering the combustion unit 16. Part of the flue gas enters the inner circulation jet bed pyrolysis unit 1, and the other part enters the steam generation unit 17 to generate steam. The steam enters the bottom of the settling section 2 of the inner circulation jet bed pyrolysis unit 1 tangentially, promoting gas-solid mixing and turbulence, prolonging the solid phase residence time, and improving mass and heat transfer efficiency and pyrolysis depth. The heating section 8 is located outside the conical section 3, and the heating method is microwave irradiation, which works in conjunction with flue gas heating to form a multi-stage heating system that combines direct and indirect heating for high-efficiency thermal integration. The flue gas stream from the steam generating unit 17 enters the heating jacket of the screw feeder 12, and then enters the hollow shaft of the roller extruder 11 to heat the raw materials in the raw material feeding unit, thereby improving system efficiency. The screw unloader 5 transports the solids discharged from the bottom of the internal circulation sputtering bed pyrolysis unit 1 and the solids separated by the cyclone separator 13 to the material sealing unit 6. The material sealing unit 6 adopts a sloping structure and is equipped with two baffles inside. Each baffle is 20mm away from the bottom. The material sealing unit 6 receives solid particles inside the baffles. The solid particles flow through the gap between the baffles and the bottom to the material circulation unit 7 step by step. The material circulation unit 7 uses air as the conveying gas. The air conveys the solid particles to the cyclone separator 2 (18) and the solid product discharge unit. Including cyclone separator three (20), solid product high-level collection tank (21), cyclone separator four (22), and solid product low-level collection tank (23), after gas-solid separation in cyclone separator two (18), the gas enters the circulating gas purification unit 19, and the solid enters the conical section (3) of the inner circulating spray bed pyrolysis unit 1, thus forming a multi-dimensional circulation mode combining the upper and lower circulation of the inner circulation cylinder 4, the inner and outer circulation, and the material circulation unit 7, which prolongs the solid residence time, improves the pyrolysis depth and system efficiency. The gas from cyclone separator three (20) and cyclone separator four (22) enters the circulating gas purification unit 19, and the solid is collected by the solid product high-level collection tank (21) and the solid product low-level collection tank (23) and output as solid product.
[0018] (Example 2, see) Figure 1 )
[0019] The difference between this embodiment and embodiment 1 is that the raw material is a mixture of fruit shells and ferric nitrate. After impregnation, mixing, filtration and pre-drying, it is transported to the internal circulation spouting bed pyrolysis unit 1 as raw material. The material sealing unit 6 is equipped with three partitions, each partition leaving a 30mm gap with the bottom. The material circulation unit 7 uses carbon dioxide as the conveying gas and is recycled. The other system components are the same as in embodiment 1.
[0020] (See Example 3) Figure 1 )
[0021] The difference between this embodiment and embodiment 1 is that the raw material is a mixture of corn stalks and ferric chloride. After impregnation, mixing, filtration and pre-drying, it is transported to the internal circulation spouting bed pyrolysis unit 1 as raw material. The material sealing unit 6 is equipped with four partitions, each partition leaving a 35mm gap with the bottom. The material circulation unit 7 uses nitrogen as the conveying gas and is used in a cyclic manner. The other system components are the same as in embodiment 1.
[0022] (See Example 4) Figure 1 )
[0023] The difference between this embodiment and embodiment 1 is that the raw material is a mixture of sawdust and ferric sulfate. After impregnation, mixing, filtration and pre-drying, it is transported to the internal circulation spouting bed pyrolysis unit 1 as raw material. The material sealing unit 6 is equipped with five partitions, each partition leaving a 40mm gap with the bottom. The material circulation unit 7 uses the flue gas after the raw material is dried and cooled as the conveying gas. The other system components are the same as in embodiment 1.
[0024] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A system for preparing catalysts by internal circulation enhanced jet pyrolysis, comprising, in sequence, a raw material feeding unit, an internal circulation jet bed pyrolysis unit (1), a screw unloader (5), a material sealing unit (6), a material circulation unit (7), a pyrolysis gas condenser (14), a pyrolysis gas purification unit (15), a circulating gas purification unit (19), and a solid product discharge unit. The raw material feeding unit comprises, in sequence, a raw material conveyor (9), a closed hopper (10), a roller extruder (11), and a screw feeder (12). The internal circulation jetting bed pyrolysis unit (1) is connected to the screw unloader (5), the combustion unit (16), the cyclone separator one (13) and the cyclone separator two (18). The cyclone separator one (13) is connected to the internal circulation jetting bed pyrolysis unit (1), the screw unloader (5) and the pyrolysis gas condenser (14). The pyrolysis gas condenser (14) is connected to the pyrolysis gas purification unit (15). The pyrolysis gas purification unit (15) is connected to the combustion unit (16). The combustion unit ( 16) and steam generating unit (17), internal circulation jetting bed pyrolysis unit (1) are connected; steam generating unit (17) and screw feeder (12) are connected; screw feeder (12) and roller extruder (11), internal circulation jetting bed pyrolysis unit (1) are connected; cyclone separator II (18) and circulating gas purification unit (19), internal circulation jetting bed pyrolysis unit (1) are connected; screw unloader (5) and material sealing unit (6) are connected; material sealing unit (6) and material circulation unit (7) are connected; solid product The discharge unit includes cyclone separator three (20), high-level solid product collection tank (21), cyclone separator four (22) and low-level solid product collection tank (23). The material circulation unit (7) is connected to cyclone separator two (18), cyclone separator three (20) and cyclone separator four (22). Cyclone separator three (20) is connected to high-level solid product collection tank (21) and circulating gas purification unit (19). Cyclone separator four (22) is connected to low-level solid product collection tank (23) and circulating gas purification unit (19). Steam from the steam generating unit (17) enters tangentially into the bottom of the settling section (2) of the internal circulation sputtering bed pyrolysis unit (1). The steam inlet is located on the side of the settling section (2) at the junction of the settling section (2) and the conical section (3). The flue gas stream from the steam generating unit (17) is connected to the jacket of the screw feeder (12) through a pipe. The flue gas from the jacket of the screw feeder (12) is connected to the hollow shaft of the roller extruder (11).
2. The system for preparing a catalyst by internal circulation enhanced jet pyrolysis according to claim 1, characterized in that... The internal circulation jetting bed pyrolysis unit (1) includes a settling section (2), a conical section (3), an internal circulation cylinder (4), and a heating section (8). The internal circulation jetting bed pyrolysis unit (1) adopts a vertical structure combining internal and external circulation, upper and lower circulation, and multi-stage heating. The internal circulation cylinder (4) is placed at the bottom of the internal circulation jetting bed pyrolysis unit (1) and is symmetrically positioned at the center. The cyclone separator II (18) is connected to the internal circulation jetting bed pyrolysis unit (1) through a pipe. The pipe below the cyclone separator II (18) enters the internal circulation jetting bed pyrolysis unit (1) and is placed outside the internal circulation cylinder (4). The heating section (8) is placed outside the conical section (3). The heating section (8) adopts microwave irradiation, electromagnetic induction heating, or electric heating.
3. The system for preparing a catalyst by internal circulation enhanced jet pyrolysis according to claim 1, characterized in that: The material sealing unit (6) adopts an inclined slope mechanism. The material sealing unit (6) is equipped with a partition, and there is a gap between the partition and the slope below.
4. The system for preparing a catalyst by internal circulation enhanced jet pyrolysis according to claim 1, characterized in that: The screw unloader (5) is connected to the internal circulation spray bed pyrolysis unit (1) and cyclone separator (13) through a pipeline. The screw pitch of the screw unloader (5) gradually decreases and the minimum screw pitch is 50% of the screw blade diameter. The discharge port of the screw unloader (5) is located inside the partition of the material sealing unit (6).
Citation Information
Patent Citations
System for preparing catalyst through internal circulation reinforced spouted pyrolysis
CN221753242U