Multi-section tandem fluidized bed reaction system

Abstract

The utility model relates to a multi-section tandem fluidized bed reaction system in the technical field of gas-solid fluidized beds. The multi-section tandem fluidized bed reaction system comprises a gas-solid separation area, a multi-section tandem reaction area and a solid material receiving and circulating area which are sequentially communicated from top to bottom, the gas-solid separation area is sequentially provided with a gas collection chamber, an upper separation chamber and a lower separation chamber from top to bottom, a plurality of gas phase outlets are uniformly distributed on the inner top wall of the upper separation chamber and are communicated with a filter of the gas collection chamber, and the lower separation chamber is provided with a plurality / group of cyclone separators of which the gas phase outlets are communicated with the upper separation chamber; the cyclone separators are in one-to-one correspondence connection with the gas phase outlets of the sectional reaction zones of the multi-section series reaction zone and the circulating part of the solid material receiving and circulating zone; according to the fluidized bed reaction system disclosed by the utility model, each reaction area is communicated with the lower separation chamber of the gas-solid separation area through the respective gas phase outlet line, and the outlet pressure is completely the same, so that the pressure of the fluidized bed reaction system can be kept stable, and materials in each reaction area are prevented from being mixed.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of gas-solid fluidized bed, especially to a multi-section series fluidized bed reaction system. BACKGROUND

[0002] Fluidized bed reactor is more and more concerned in the field of chemical vapor deposition (CVD) due to its high heat and mass transfer efficiency, uniform bed temperature and large operation flexibility. By using fluidized bed CVD technology, a layer or multiple layers of functional thin film or coating can be uniformly coated on the surface of ultra-fine solid particles, greatly improving their performance and application fields. For example, by using fluidized bed CVD technology to coat silicon and / or amorphous carbon on the surface of ultra-fine graphite, the capacity, stability and rate performance of lithium-ion batteries can be greatly improved.

[0003] However, the particle size of ultra-fine solid particles used for fluidized bed coating is generally less than 20 μm, which belongs to C-type particles according to Geldart particle classification method. There is strong van der Waals force and electrostatic force between the particles, and phenomena such as channeling, caking, agglomeration or surging are easy to occur during fluidization process, causing bed pressure instability and serious deterioration of coating effect. This phenomenon is particularly prominent in the commonly used upflow fluidized bed. In addition, the above coating reactions are mostly strong endothermic reactions, and heat needs to be continuously supplied to the system during the reaction process. To solve this problem, the existing technology generally uses external heating furnace for fixed fluidized bed reactor or uses rotary tunnel kiln reactor mode, which has the common disadvantage of low reaction efficiency, uneven coating layer or agglomeration phenomenon, and is difficult to apply to the coating process of multiple raw materials, becoming a technical problem to be solved in the field of ultra-fine solid particle coating.

[0004] The existing Chinese utility model patent CN114950283B discloses a fluidized reaction equipment for superfine particle surface coating and its use method. Superfine particles are circulated between the down-flow fluidized reaction zone and the up-flow fluidized reaction zone multiple times to achieve uniform coating of the superfine particle surface, better solving the problems of fluidization and wall adhesion reaction in the superfine particle fluidization CVD coating technology, and improving the yield and quality of superfine powder coating materials. However, since the down-flow bed reactor has only one, the residence time of superfine particles in it is limited, and each coating raw material needs multiple circulation reactions to achieve sufficient coating layer thickness, and each production cycle can only complete the coating process of one raw material, still existing many problems such as low product yield and difficulty in switching different coating raw materials. Chinese utility model patent CN105130727B discloses a three-stage series fluidized bed reactor for methanol-to-olefin reaction and a method for preparing olefins by using the reactor. The reaction products and unreacted methanol raw materials are separated from the catalyst and then enter the next stage reactor for continuous reaction. The catalyst continuously flows in the three-stage reactor. The first-stage reactor adopts a fast bed, the second-stage reactor adopts a turbulent bed, and the third-stage reactor adopts a bubbling bed. The utility model realizes the staged use of the catalyst by using a multi-stage series reactor, maximizes the performance of the catalyst, and reduces the carbon burning load of the regenerator. However, since the utility model is developed for the characteristics of the methanol-to-olefin reaction, the reactor is in the form of an up-flow fluidized bed, and each stage reactor adopts a parallel arrangement mode. The catalyst meets the technical requirements of ordinary fluidized bed B-type particles, and the catalyst particles need to be continuously up-flow back-mixed fluidized in the reactor. Therefore, the residence time of the catalyst in the same reactor is greatly different, which is completely unsuitable for the fluidization and coating process of C-type superfine particles. Chinese utility model patent CN102766480B discloses a solid organic fuel two-stage series fluidized bed pyrolysis gasification device, which includes a first-stage fluidized bed reactor and a second-stage fluidized bed reactor arranged in series, a gas-solid separation device, and a gas-liquid separation device. The combustion or gasification of the organic solid fuel is first carried out in the first-stage fluidized bed reactor. The high-temperature flue gas or fuel gas discharged is sent to the second-stage fluidized bed reactor for gasification or pyrolysis. The unburned solids of the second-stage fluidized bed and the newly entered organic solid raw materials are used as the combustion raw materials of the first-stage fluidized bed. The advantages are that the heat released during the combustion or gasification of the organic solid fuel is fully utilized, the pyrolysis gas quality is improved, and high-quality high-calorific-value solid fuel, fuel gas, and tar products can be produced. Although the two-stage fluidized bed of the utility model adopts an up-down series form, the reactors are all up-flow fluidized beds, and the raw material supply process is completely different from the fluidized bed CVD coating. Therefore, it is also not suitable for the fluidization and coating process of C-type superfine particles.

[0005] Therefore, we designed a multi-stage series fluidized bed reaction system. The utility model discloses a kind of multi-section series fluidized bed reaction systems, to solve the problems of short single reactor residence time, cannot continuously heat solid particles, need solid particles multiple circulation to reach enough coating layer thickness, and only complete one raw material coating process in each production cycle, simultaneously realize multiple raw material coating and improve target product yield in multi-section series down-flow fluidized bed reaction system.

[0006] In order to overcome the deficiencies in the background art, the utility model discloses a kind of multi-section series fluidized bed reaction systems, to solve the problems of short single reactor residence time, cannot continuously heat solid particles, need solid particles multiple circulation to reach enough coating layer thickness, and only complete one raw material coating process in each production cycle, simultaneously realize multiple raw material coating and improve target product yield in multi-section series down-flow fluidized bed reaction system.

[0007] To achieve the above-mentioned utility model purposes, the utility model adopts the following technical solutions:

[0008] A kind of multi-section series fluidized bed reaction system, including by upper to lower sequentially communicating gas-solid separation zone, multi-section series reaction zone and solid material receiving circulation zone;

[0009] The gas-solid separation zone has a gas collection chamber, an upper separation chamber and a lower separation chamber from top to bottom in sequence, a plurality of gas phase outlets of the upper separation chamber are uniformly distributed on the top wall and connected to the filter of the gas collection chamber, a plurality of cyclone separators of the lower separation chamber are connected to the gas phase outlets of the upper separation chamber, and the cyclone separators are connected to the gas phase outlets of each section of the multi-section series reaction zone and the circulation part of the solid material receiving circulation zone in one-to-one correspondence;The top of the gas collection chamber is connected with a tail gas outlet line, and the bottom of the upper separation chamber and the lower separation chamber is provided with a discharge channel corresponding to the feed inlet of the multi-section series reaction zone.

[0010] Preferably, the bottom of the upper separation chamber and the lower separation chamber is inclined from top to bottom, and the lower end of the bottom of the lower separation chamber is provided with a separation zone discharge pipe connected to the solid particle injection preheating zone, and the lower end of the bottom of the upper separation chamber is provided with an upper separation chamber discharge pipe with the discharge port close to the separation zone discharge pipe.

[0011] Preferably, the upper separation chamber discharge pipe is attached to the inner side wall of the lower separation chamber, and the lower end of the upper separation chamber discharge pipe is located directly above the upper end of the separation zone discharge pipe.

[0012] Preferably, the section of the multi-section series reaction zone has a reactor and a storage device connected from top to bottom, the inner cavity of the reactor is provided with a distributor and a material disperser with a stepped shape and without a bottom, the side wall of the distributor is connected with a coating raw material feed line, the bottom of the storage device is connected with a loose air feed line, and the bottom of the storage device is connected to the next section or the solid material receiving circulation zone through a plug valve.

[0013] Wherein, the outer periphery of the reactor dense phase zone and the outer periphery of the storage device are wrapped with a reaction heater;The gas phase outlet of the top of the reactor is connected to the corresponding cyclone separator.

[0014] Preferably, the reaction heater adopts a heater with the functions of zoned heating and temperature control.

[0015] Preferably, the distributor is located at the joint of the material disperser and the reactor.

[0016] Preferably, the solid material receiving and circulating zone comprises a feed pipe with an upper end in communication with the corresponding multi-stage serially connected reaction zone, a product tank connected to the lower end of the feed pipe, a solid product sampling assembly, a riser and a riser air duct in communication with the feed pipe, wherein the upper end of the riser is connected to the corresponding cyclone separator, and the outlet of the riser air duct corresponds to the inlet of the riser.

[0017] Preferably, a solid particle charging and preheating zone is arranged between the gas-solid separation zone and the multi-stage serially connected reaction zone.

[0018] Preferably, the solid particle charging and preheating zone comprises an intermediate tank with a top feed port in communication with the discharge channel of the gas-solid separation zone, a solid particle charging line in communication with the top feed port of the intermediate tank, an intermediate tank heater wrapped around the periphery of the intermediate tank, and a feed control valve arranged at the bottom of the intermediate tank and in communication with the feed port of the multi-stage serially connected reaction zone.

[0019] Preferably, the multi-stage serially connected reaction zone is arranged in a straight line from top to bottom, inclined downward or in a Z shape.

[0020] Due to the adoption of the above technical solutions, the utility model has the following beneficial effects:

[0021] 1. Each reaction zone is in communication with the lower separation chamber of the gas-solid separation zone through a respective gas phase outlet line, and since the outlet pressures are completely the same, the pressure of the fluidized bed reaction system can be kept stable, and the materials of the reaction zones can be prevented from being mixed;

[0022] 2. The combination of the multi-stage serially connected downflow type fluidized bed reactor increases the residence time of the solid particles in the reaction system, and solves the problem of insufficient residence time of a single downflow bed reactor;

[0023] 3. The lower part of each reaction zone is provided with a heater that can be independently heated and temperature controlled, and the solid particles that have undergone coating reaction are heated and warmed multiple times, and sufficient heat is provided for the subsequent coating reaction;

[0024] 4. Different reaction zones can use the same coating raw material or different coating raw materials, and the solid particles can be coated multiple times in the same raw material atmosphere, or the solid particles can be coated with multiple raw materials and multiple layers in one pass, thereby improving the coating efficiency of the solid particles and the product yield;

[0025] 5. Each reactor employs a bottomless, trapezoidal material disperser at the bottom. Utilizing the upward lifting effect of the fluidizing and loosening air in the storage section, a stable dense-phase bed is formed at the bottom of the reactor, prolonging the reaction time of solid particles.

[0026] 6. The gas-solid separation zone and the multi-reaction zone are stacked in series, which avoids the solid particles being lifted multiple times between different reactors, reduces equipment wear and fine powder generation, and helps to improve the yield of coated products and extend the service life of the equipment.

[0027] 7. The gas-solid separation zone is divided into multiple independent areas. A combination of cyclone separation and filtration separation is used for solid-containing gas, which significantly improves the gas-solid separation efficiency and the recovery rate of ultrafine solid particles, reduces the dust content of exhaust gas, and helps protect the production environment.

[0028] In summary, compared with the existing technology, this utility model solves the problems of short residence time in a single reactor and inability to continuously reheat solid particles in the C-type ultrafine particle fluidized bed CVD coating technology. It can realize multiple relay coating under the same raw material conditions, as well as multi-layer coating of different raw materials in a single pass, which is conducive to improving the yield and output of the target product, enhancing the stability of the fluidized bed reaction system, and reducing equipment investment and dust pollution. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the present invention.

[0030] In the diagram: I. Gas-solid separation zone:

[0031] 1-1. Exhaust gas outlet line; 1-2. Gas collection chamber; 1-3. Filter; 1-4. Upper separation chamber; 1-5. Circulating material cyclone separator; 1-6. Three-stage counter-cyclone separator; 1-7. Two-stage counter-cyclone separator; 1-8. One-stage counter-cyclone separator; 1-9. Lower separation chamber; 1-10. Upper partition of separation chamber; 1-11. Lower partition of separation chamber; 1-12. Upper separation chamber discharge pipe; 1-13. Separation zone discharge pipe;

[0032] II. Solid Particle Injection Preheating Zone:

[0033] 2-1. Solid pellet filling line; 2-2. Intermediate tank; 2-3. Intermediate tank heater; 2-4. Feed control valve;

[0034] III. First Reaction Zone:

[0035] 3-1, first reactor; 3-2, first reactor heater; 3-3, first reactor distributor; 3-4, first reactor material disperser; 3-5, first reactor material accumulator; 3-6, first reactor downcomer; 3-7, first reactor stop valve; 3-8, first reactor feed preheater; 3-9, first reactor fluidization air preheater; 3-10, first reactor gas phase outlet line;

[0036] IV, second reaction zone:

[0037] 4-1, second reactor; 4-2, second reactor heater; 4-3, second reactor distributor; 4-4, second reactor material disperser; 4-5, second reactor material accumulator; 4-6, second reactor downcomer; 4-7, second reactor stop valve; 4-8, second reactor feed preheater; 4-9, second reactor fluidization air preheater; 4-10, second reactor gas phase outlet line;

[0038] V, third reaction zone:

[0039] 5-1, third reactor; 5-2, third reactor heater; 5-3, third reactor distributor; 5-4, third reactor material disperser; 5-5, third reactor material accumulator; 5-6, third reactor downcomer; 5-7, third reactor stop valve; 5-8, third reactor feed preheater; 5-9, third reactor fluidization air preheater; 5-10, third reactor gas phase outlet line;

[0040] VI, solid material receiving and recycling zone:

[0041] 6-1, lift gas preheater; 6-2, solid product sampling assembly; 6-3, discharge control valve; 6-4, product tank; 6-5, recycle control valve; 6-6, lift tube;

[0042] 7, first recycle line; 7-1, first reactor gas phase valve; 8, second recycle line; 8-1, second reactor gas phase valve; 9, third recycle line; 9-1, third reactor gas phase valve;

[0043] S, solid particles; F1, first coating feed material; F2, first fluidization air; F3, second coating feed material; F4, second fluidization air; F5, third coating feed material; F6, third fluidization air; F7, lift gas; P1, offgas; P2, intermediate sample; P3, solid product. DETAILED DESCRIPTION

[0044] The utility model can be explained in detail by the following examples, the purpose of the utility model is disclosed in all technical improvements within the scope of the utility model, in the description of the utility model, it is understood that, if there are terms "upper", "lower", "front", "rear", "left", "right" and so on indicate the orientation or position relation, only with the drawing of the application, for the convenience of describing the utility model, it is understood that, if there are terms "end", "side", "end", "side", "transverse", "longitudinal" and so on indicate the orientation or position relation, only the length and width of the corresponding component, namely "end" indicates the head and tail area of the length direction of the corresponding component, "side" indicates the head and tail area of the width direction of the corresponding component, for the convenience of describing the utility model, not indicating or suggesting that the device or element must have a specific orientation.

[0045] Combining the drawings Figure 1 A multi-section series fluidized bed reaction system, the gas-solid separation zone I, the multi-section series reaction zone and the solid material receiving and circulating zone VI are sequentially communicated from top to bottom, according to the need, the solid particle charging and preheating zone II can also be arranged between the gas-solid separation zone I and the multi-section series reaction zone.

[0046] For the convenience of description, the multi-section series reaction zone is described as having three sectional reaction zones, from top to bottom, the first reaction zone III, the second reaction zone IV and the third reaction zone V are sequentially arranged, wherein.

[0047] At this time, the reaction system includes the gas-solid separation zone I, the solid particle charging and preheating zone II, the first reaction zone III, the second reaction zone IV, the third reaction zone V and the solid material receiving and circulating zone VI, the gas-solid separation zone I is located at the uppermost end of the whole reaction system, sequentially communicating the solid particle charging and preheating zone II, the first reaction zone III, the second reaction zone IV, the third reaction zone V and the solid material receiving and circulating zone VI from top to bottom, the connecting channels between them are mainly used for the flow of the solid particles from top to bottom, the solid material receiving and circulating zone VI is communicated with the gas-solid separation zone I through the upward movement of the lifting pipe 6-6, the solid particles which do not meet the coating requirements are lifted to the gas-solid separation zone I, thus establishing the circulation of most of the solid particles in the reaction system; the gas phase products of the first reaction zone III, the second reaction zone IV and the third reaction zone V are communicated with the gas-solid separation zone I through the corresponding gas phase outlet lines 3-10, 4-10 and 5-10, and the high-efficiency separation of gas and solid is completed through the combined means of cyclone separation + filtration, a small amount of superfine solid particle powder carried out by the gas phase products and the lifting wind is recovered, at the same time, the pressure of the reaction system can be kept stable, and the mutual stringing of the materials of the sectional reaction zones is prevented;

[0048] The gas-solid separation zone I is a place for separating all gas phases and solid phases of the reaction system, including the tail gas outlet line 1-1, the gas collection chamber 1-2, the filter 1-3, the upper separation chamber 1-4, the circulating material cyclone separator 1-5, the three-stage cyclone separator 1-6, the two-stage cyclone separator 1-7, the one-stage cyclone separator 1-8, the lower separation chamber 1-9, the upper separation chamber partition plate 1-10, the lower separation chamber partition plate 1-11, the upper separation chamber discharge pipe 1-12, and the separation zone discharge pipe 1-13. The gas-solid separation zone I is divided into three isolated areas, i.e., the gas collection chamber 1-2, the upper separation chamber 1-4, and the lower separation chamber 1-9, from top to bottom by the upper and lower separation chamber partition plates. According to the need, the gas collection chamber 1-2 is a flat cylindrical body, the top of which is communicated with the tail gas outlet line 1-1, and the bottom, i.e., the upper separation chamber partition plate 1-10, is sealed and installed with a plurality of filters 1-3 with gas phase outlets facing the gas collection chamber 1-2. According to the need, the pore size of the filter 1-3 is 1 μm. The filter 1-3 functions to filter and separate the solid particle fines not removed by the cyclone separator, greatly reduces the content of solid particles in the discharged tail gas, and maximizes the yield of solid particles. The bottom of the upper separation chamber 1-4, i.e., the lower separation chamber partition plate 1-11, is an inclined structure. It should be noted that the angle between the bottom of the upper separation chamber 1-4 and the horizontal plane must be greater than the angle of repose of the solid particles used. The gas phase outlet lines of the one-stage cyclone separator 1-8, the two-stage cyclone separator 1-7, the three-stage cyclone separator 1-6, and the circulating material cyclone separator 1-5 pass through the lower separation chamber partition plate 1-11 and are communicated with the upper separation chamber 1-4. The lower separation chamber 1-9 in the lower area of the gas-solid separation zone I is installed with the one-stage cyclone separator 1-8, the two-stage cyclone separator 1-7, the three-stage cyclone separator 1-6, and the circulating material cyclone separator 1-5, and the lower bottom thereof is an inclined structure. It should be noted that the angle between the bottom of the lower separation chamber 1-9 and the horizontal plane must be greater than the angle of repose of the solid particles used.

[0049] According to the need, the one-stage cyclone separator 1-8, the two-stage cyclone separator 1-7, the three-stage cyclone separator 1-6, and the circulating material cyclone separator 1-5 can adopt a single-stage single-unit mode or a multi-stage mode of multiple units in series or parallel.

[0050] The upper separation chamber discharge pipe 1-12 is installed at the position of the lowest point of the separation chamber close to the wall and extends downward to the position close to the lower part of the middle part of the lower separation chamber, so as to guide the solid particle fines collected in the upper separation chamber 1-4 into the lower separation chamber 1-9. The separation zone discharge pipe 1-13 is located at the lowest end of the lower separation chamber 1-9, the outlet of which is communicated with the top of the intermediate tank 2-2, so as to circulate the solid particles collected in the gas-solid separation zone I back to the intermediate tank 2-2.

[0051] The solid particle charging preheating zone II is a place for charging and preheating of fresh solid particles in the reaction system, and comprises a solid particle charging line 2-1, an intermediate tank 2-2, an intermediate tank heater 2-3 and a feed control valve 2-4; the solid particle charging line 2-1 and the separation zone discharge pipe 1-13 are connected to the top of the intermediate tank, and the intermediate tank heater 2-2 is wrapped outside the intermediate tank 2-2 to heat the solid particles entering the intermediate tank to the required temperature for the first coating reaction; the feed control valve 2-4 is installed on the discharge pipe line at the bottom of the intermediate tank to accurately control the flow of solid particles into the first reactor 3-1;

[0052] The first reaction zone III is a place for the first coating reaction of the solid particles in the reaction system, and comprises a first reactor 3-1, a first reactor heater 3-2, a first reactor distributor 3-3, a first reactor material disperser 3-4, a first reactor storage 3-5, a first reactor discharge pipe 3-6, a first reactor valve 3-7, a first reactor raw material preheating assembly 3-8, a first reactor fluidization loosening air preheating assembly 3-9 and a first reactor gas phase outlet line 3-10; wherein the first reactor 3-1 is located at the uppermost part of the first reaction zone III, and is sequentially connected downward to the first reactor storage 3-5, the first reactor valve 3-7 and the first reactor discharge pipe 3-6; the upper part of the first reactor 3-1 is cylindrical, and the lower part is a stepped form without a bottom first reactor material disperser 3-4, which can utilize the lifting effect of the upward flow of the fluidization loosening air in the first reactor storage 3-5 to form a stable dense phase bed at the lower part of the first reactor heater 3-2, thereby prolonging the residence time of the solid particles in the first reactor heater 3-2 and being beneficial to increasing the thickness of the coating layer; the first reactor distributor 3-3 is located at the joint of the first reactor cylinder and the first reactor material disperser 3-4, and the first reactor distributor 3-3 penetrates the side wall of the first reactor heater 3-2 cylinder to be connected with the first coating raw material feeding line and the first reactor raw material preheating assembly 3-8; that is, the first coating raw material enters the first reactor distributor 3-3 through the first coating raw material feeding line; the first reactor storage 3-5 is equal in diameter to the first reactor 3-1 cylinder and is sealingly connected to the lower part of the first reactor 3-1; the first reactor loosening air feeding line enters the bottom of the first reactor storage 3-5 from the side after passing through the first reactor loosening air preheating assembly 3-9; that is, the first reactor fluidization loosening air F2 enters the first reactor storage 3-5 through the first reactor loosening air feeding line; the first reactor heater 3-2 is wrapped outside the lower dense phase section of the first reactor and the first reactor storage 3-5; according to the need, the first reactor heater 3-2 can adopt a partition heating and temperature control mode corresponding to the above two regions to realize the function of flexible adjustment of the temperature of different regions and conveniently realize the re-heating of the solid particles after the coating reaction; the first reactor gas phase outlet line 3-10 is connected to the top of the first reactor heater 3-2 and is connected with the first reactor cyclone separator 1-8 through a rotary induction line 7; the first reaction zone III is connected with the second reaction zone IV through the first reactor discharge pipe 3-6;

[0053] It should be noted that the first distributor 3-3 uses existing equipment, and its specific structure and working principle will not be described again here.

[0054] It should be noted that: the first reactor storage device 3-5 is open at the top, and the upper edge of the first reactor material disperser 3-4, the upper edge of the first reactor storage device 3-5, and the lower edge of the first reactor 3-1 are connected together.

[0055] The second reaction zone IV and the third reaction zone V are the secondary and tertiary coating reaction sites for solid particles in this reaction system, respectively. Their structural composition and connection methods are exactly the same as those of the first reaction zone I, depending on the requirements. The solid particles flowing out of the previous reaction zone undergo the same process as those in the first reaction zone, which will not be elaborated here. It should only be noted that: the secondary coating material F3 in the second reaction zone IV enters the second reaction zone IV through the secondary coating material feed line; the secondary fluidizing loosening air F4 in the second reaction zone IV enters the second reaction zone IV through the secondary loosening air feed line; the tertiary coating material F5 in the third reaction zone V enters the third reaction zone V through the tertiary coating material feed line; and the tertiary fluidizing loosening air F6 in the third reaction zone V enters the third reaction zone V through the tertiary loosening air feed line.

[0056] Depending on the needs, the number of reaction zones III, IV, and V can be reduced to two or increased to three or more; their arrangement can be supplementary. Figure 1 The “Z” shape shown can also be a layout that tilts to the left or right from top to bottom. This series of multiple reaction zones, which are stacked one on top of the other, increases the residence time of solid particles in the reaction system, solves the problem of insufficient residence time in a single downward-flowing bed reactor, and also avoids the solid particles being lifted multiple times between different reactors, reducing equipment wear and the generation of fine powder. This is conducive to improving the yield of coated products and extending the service life of the equipment.

[0057] Solid material receiving and recycling zone VI is the place for sampling and analysis of solid particles after coating reaction, product recovery, and recycling of solid particles that do not meet the coating thickness requirements. It includes lifting air preheating component 6-1, solid product sampling component 6-2, discharge control valve 6-3, product tank 6-4, circulation control valve 6-5, and lifting pipe 6-6. The third reaction zone V's three-stage discharge pipe 5-6 is inclined downward and sequentially connected to lifting pipe 6-6, solid product sampling component 6-2, discharge control valve 6-3, and product tank 6-4. Lifting air preheating component 6-1 is connected to the inlet end (lowest end) of lifting pipe 6-6, and the outlet end of lifting pipe 6-6 is connected to the circulating material cyclone separator 1-5 in the gas-solid separation zone.

[0058] It should be noted that the heaters, preheating components and solid product sampling components mentioned above all use existing equipment, and their structure and operating principles will not be described again here.

[0059] A method for using a multi-stage down-flow fluidized bed reaction system, comprising the following steps:

[0060] Process I, solid particle charging and preheating

[0061] Solid particles S are added into the intermediate tank 2-2 along the solid particle charging line 2-1, and are preheated to the required temperature for the first coating reaction by the intermediate tank heater 2-3, and then enter the top of the first reactor 3-1 at a certain flow rate through the feed control valve 2-4;

[0062] Process II, first coating reaction

[0063] The solid particles entering the top of the first reactor 3-1 flow downward uniformly, and the first coating raw material F1 is heated to a predetermined temperature by the first raw material preheating assembly 3-8, and then enters the first reactor 3-1 from the first reactor distributor 3-3 located at the lower part of the first reactor 3-1. The upward first coating raw material F1 and the downward hot solid particles are in countercurrent contact to form a coating layer with a certain thickness on the surface of the solid particles. The solid particles after the first coating enter the first reactor storage tank 3-5 through the first material distributor 3-4, and are in a loose fluidized state under the action of the first fluidizing and loosening air F2 preheated by the first fluidizing and loosening air preheating assembly 3-9, and are re-heated to the required temperature for the second coating reaction by the first heater 3-2. Then, the first reactor valve 3-7 and the first discharge pipe 3-6 are used to feed the second reactor 4-1 from the top of the second reactor. The presence of the first fluidizing and loosening air F2 promotes the heating speed of the solid particles, and the upward movement of the first fluidizing and loosening air F2 from the first material distributor 3-4 also limits the flow of the first coating particles from the first reactor 3-1 into the first reactor storage tank 3-5, which helps to form a dense phase section at the bottom of the first reactor 3-1, and prolongs the residence time and reaction time of the first coating particles in the first reactor 3-1. The first gas phase product carrying a small amount of solid particle fine powder enters the first cyclone separator 1-8 in the gas-solid separation zone along the first gas phase outlet line 3-10 and the first cyclone line 7. If necessary, the first fluidizing and loosening air F2 is an inert gas, preferably nitrogen;

[0064] Process III, second coating reaction

[0065] The primary coated solid particles entering the second reactor 4-1, under the action of the secondary coating raw material F3, the secondary fluidization loosening air F4 and the secondary heater 4-2, undergoes a similar reaction and reheating process as the process two, and the secondary gas phase product carrying a small amount of solid particles enters the secondary cyclone separator 1-7 in the gas-solid separation zone along the secondary gas phase outlet line 4-10 and the secondary cyclone induction line 8, and the secondary coated particles in the secondary storage 4-5, after being preheated again, enter the third reactor 5-1 from the top of the third reactor through the secondary valve 4-7 and the secondary discharge pipe 4-6 at a certain flow rate; the secondary coating raw material F3 can be the same as the primary coating raw material F1 or different from the primary coating raw material F1; according to the needs, the secondary fluidization loosening air F4 is an inert gas, preferably nitrogen;

[0066] Process four, tertiary coating reaction

[0067] The secondary coated solid particles entering the third reactor 5-1, under the action of the tertiary coating raw material F5, the tertiary fluidization loosening air F6 and the tertiary heater 5-2, undergoes a similar reaction and reheating process as the process two, and the tertiary gas phase product carrying a small amount of solid particle fines enters the tertiary cyclone separator 1-6 in the gas-solid separation zone along the tertiary gas phase outlet line 5-10 and the tertiary cyclone induction line 9, and the tertiary coated particles in the tertiary storage 5-5, after being preheated, enter the solid material receiving and circulating zone VI through the tertiary valve 5-7 and the tertiary discharge pipe 5-6 at a certain flow rate; the tertiary coating raw material F5 can be the same as the primary coating raw material F1 and the secondary coating raw material F3, or different from the primary coating raw material F1 and the secondary coating raw material F3; according to the needs, the secondary fluidization loosening air F4 is an inert gas, preferably nitrogen;

[0068] Process five, receiving and circulating of solid material

[0069] The tertiary coated particles flowing out of the tertiary discharge pipe 5-6 are divided into three paths, the first path communicates with the solid product sampling assembly 6-2, the second path communicates with the discharge control valve 6-3 and the product tank 6-4, and the third path communicates with the lifting pipe 6-6; the intermediate product P2 is sampled through the solid product sampling assembly 6-2, if P2 is qualified, the circulating control valve 6-5 is closed, the discharge control valve 6-3 is opened, and the qualified solid particles are sent into the product tank 6-4 along the second path as the solid product P3; if P2 is unqualified, the circulating control valve 6-5 is opened, the discharge control valve 6-3 is closed, and under the action of the lifting air F7 preheated by the lifting air preheating assembly 6-1, is transported to the circulating material cyclone separator 1-5 in the gas-solid separation zone I along the lowest end of the lifting pipe 6-6; according to the needs, the lifting air F7 is an inert gas, preferably nitrogen;

[0070] Process six, gas-solid separation

[0071] The gas-solid flow entering the first-stage cyclone separator 1-8, the second-stage cyclone separator 1-7, the third-stage cyclone separator 1-6 and the circulating material cyclone separator 1-5 is subjected to gas-solid separation in the corresponding cyclone separator, the separated solid particles flow down along the cyclone separator leg to the inclined bottom plate of the lower separation chamber 1-9, and slide along the bottom plate to the lowest point of the lower separation chamber; the gas containing a small amount of solid particle fine powder flowing upward from the cyclone separator gas outlet enters the upper separation chamber 1-4, the gas therein passes through the filter 1-3 into the gas collection chamber 1-2, and exits the multi-stage series fluidized bed reaction system along the tail gas outlet line 1-1 as tail gas P1, the solid particle fine powder intercepted by the filter 1-3 falls onto the inclined lower separation chamber partition plate 1-11, and slides along the lower separation chamber partition plate 1-11 to the upper separation chamber lower discharge pipe 1-12, and then flows downward from the upper separation chamber lower discharge pipe 1-12 into the lower separation chamber 1-9, and together with the solid particle fine powder flowing down from the cyclone separator leg of the lower separation chamber, enters the intermediate tank 2-2 from the top along the separation zone discharge pipe 1-13, thus completing the circulation coating process of the solid particle material.

[0072] It should be noted that if it is necessary to control the thickness of the coating layer formed on the surface of the solid particles by the same coating material, the thickness of the coating layer can be controlled by adjusting the flow rate of the solid particle injection preheating zone feed control valve, using the same coating material in different reaction zones, and using a combination thereof. If the above-mentioned means still fails to achieve the required coating layer thickness, the solid particle circulation coating method can be used again. If two or more coating materials are used for coating, and the thickness of the coating layer of each material is required, the circulation coating can be switched to another material after the coating requirement of one material is met. The smaller the solid particle circulation amount or the more the circulation times, the thicker the coating layer, and vice versa.

[0073] Example 1: The reaction system comprises two reaction zones in series, each reaction zone uses the same coating material and different temperature conditions, and the solid particles pass through once without circulation.

[0074] Specifically, the solid particles S to be coated are graphite particles with a D50 particle size of 8 μm; the first-stage coating material F1 and the second-stage coating material F3 are both a mixture of acetylene (C2H2) and hydrogen (H2), wherein the molar ratio of acetylene is 0.30; the first-stage fluidization loosening air F2 and the second-stage fluidization loosening air F4 are high-purity nitrogen with a purity of 99.999%; the stripping air is ordinary nitrogen with a purity of 99.9%;

[0075] The first-stage gas phase valve 7-1 and the second-stage gas phase valve 8-1 are opened.

[0076] The 24 kg graphite particles are fed into the intermediate tank 2-2 along the solid particle feeding line 2-1, the intermediate tank heater 2-4 is turned on to preheat the graphite particles in the intermediate tank 2-2 to 920±5℃, the feeding control valve 2-4 is opened to feed the preheated graphite particles into the first reactor 3-1 of the first reaction zone I at a rate of 6 kg / h; the first reaction coating feedstock F1 preheated to 750±3℃ by the first reaction raw material preheating assembly 3-9 is fed into the first reactor from the bottom at a flow rate of 1000 NL / h, the C2H2 gas goes up along the reactor, contacts the descending hot graphite particles and reacts chemically, the C2H2 is decomposed into H2 and amorphous carbon at high temperature, and the amorphous carbon coats the surface of the graphite particles to form a carbon coating layer; the bed center temperature of the first reactor 3-1 is controlled at 760±5℃, and the operating pressure is controlled at 65±2 KPaG; since the reaction is an endothermic reaction, the temperature of the graphite particles after the reaction is reduced to about 750℃; the once-coated graphite particles flow into the first reaction storage tank 3-5 from the first reaction material distributor 3-4, the high-purity nitrogen gas preheated to about 800℃ by the first reaction fluidization loosening air preheating assembly 3-9 is introduced into the first reaction storage tank 3-5 at a flow rate of 280 NL / h to make the graphite particles in the first reaction storage tank 3-5 in a loose fluidized state; the first reaction heater 3-2 is turned on to reheat the once-coated graphite particles in the lower dense phase section of the first reactor 3-1 and the first reaction storage tank 3-5 to 950±5℃; the first reaction fluidization loosening air F2 goes up into the first reactor 3-1 from the first reaction material distributor 3-4 after passing through the first reaction storage tank 3-5 to form a dense phase section in the lower part of the first reactor 3-1; the fluidization loosening air mixed with the H2 generated in the reaction process goes out of the first reactor from the first reaction gas phase outlet line 3-10, and then enters the first reaction cyclone 1-8 located in the gas-solid separation zone I along the cyclone line 7 for gas-solid separation;

[0077] The opening of the check valve 3-7 is controlled so that the once-coated graphite particles flow downward along a check downcomer 3-6 into the second reactor 4-1 at a rate of 6 kg / h; the once-coated feedstock F3 preheated to 780±3°C by the preheating assembly 3-9 is introduced into the bottom of the second reactor 4-1 at a flow rate of 1200 NL / h from the second reactor distributor 4-3, and the C2H2 gas flows upward along the reactor, contacts the downward flowing hot graphite particles and chemically reacts with them, and the C2H2 is decomposed into H2 and amorphous carbon at high temperature, which coats the surface of the graphite particles to form a carbon coating layer; the bed center temperature of the second reactor 4-1 is controlled at 790±5°C, and the operating pressure is controlled at 65±2 KPaG; since the reaction is an endothermic reaction, the temperature of the graphite particles after the reaction is reduced to about 780°C; the once-coated graphite particles flow into the second reactor storage 4-5 from the second reactor material disperser 4-4, high-purity nitrogen preheated to about 800°C by the second reactor fluidization loosening air preheating assembly 4-9 is introduced into the second reactor storage 4-5 at a flow rate of 260 NL / h to make the graphite particles in the second reactor storage 4-5 in a loose fluidized state; the second reactor fluidization loosening air F2 flows upward into the second reactor 3-1 from the second reactor material disperser 4-4 after passing through the second reactor storage 4-5, and forms a dense phase in the lower part of the second reactor; the fluidization loosening air mixed with the H2 generated in the reaction process flows out of the second reactor from the second reactor gas phase outlet line 4-10, and then flows along the second cyclone guide line 8 into the second reactor cyclone 1-7 located in the gas-solid separation zone I for gas-solid separation;

[0078] The operating temperature of the gas-solid separation zone I is controlled at 790±5°C, and the operating pressure is the same as the pressure of each reaction zone; the ultra-fine graphite particles separated from the first reactor cyclone 1-8, the second reactor cyclone 1-7 and the filter 1-3 flow downward along the separation zone outflow pipe into the intermediate tank 2-2 to continue to participate in the coating reaction;

[0079] Due to the reduction of the solid particle feed amount and the increase of the coating feedstock feed amount, after two times of amorphous carbon coating, sampling and analysis are performed through the solid product sampling assembly 6-2, and the analysis results show that the thickness of the amorphous carbon on the surface of the twice-coated graphite particles meets the technical requirements, and the graphite particles do not need to be coated again; the second reactor heater 4-2 and the circulation control valve 6-6 are closed, the discharge control valve 6-3 is opened, and all the qualified products are transferred into the product tank 6-4.

[0080] In this embodiment, the same coating feedstock is used in two reactors in series, and the once-through process is adopted, and a total of 24.64 kg of graphite particle coating products meeting the requirements are obtained.

[0081] In Example Two, the reaction system comprises two reaction zones in series, each reaction zone uses the same coating feedstock and the same reaction conditions, and the solid particles are coated in a circulation manner.

[0082] Specifically, the solid S to be coated is graphite particles with a D50 particle size of 8 μm; the first coating raw material F1 and the second coating raw material F3 are both mixtures of acetylene (C2H2) and hydrogen (H2), with a molar ratio of acetylene of 0.15; the first fluidization loosening air F2 and the second fluidization loosening air F4 are both high-purity nitrogen with a purity of 99.999%; the stripping air is ordinary nitrogen with a purity of 99.9%;

[0083] The first reaction gas phase valve 7-1 and the second reaction gas phase valve 8-1 are opened;

[0084] 20 kg of graphite particles are added to the intermediate tank 2-2 along the solid particle filling line 2-1, the intermediate tank heater 2-4 is turned on, and the graphite particles in the intermediate tank 2-2 are preheated to 950±5℃, the feed control valve 2-4 is opened, and the preheated graphite particles enter the first reactor 3-1 of the first reaction zone I at a rate of 10 kg / h; the first reaction gas phase valve 7-1 is opened, and the first reaction gas phase outlet line 7 is connected to the first reaction gas phase inlet line 8-1; the first reaction raw material preheating assembly 3-9 is preheated to 800±3℃, and the first reaction raw material F1 enters the bottom of the first reactor at a flow rate of 1500 NL / h from the first reaction distributor 3-3; C2H2 gas flows upward along the reactor, contacts the downward flowing hot graphite particles, and chemically reacts with them; C2H2 decomposes into H2 and amorphous carbon at high temperatures, and the amorphous carbon forms a carbon coating layer on the surface of the graphite particles; the bed center temperature of the first reactor 3-1 is controlled at 780±5℃, and the operating pressure is controlled at 75±2 KPaG; since the reaction is endothermic, the temperature of the graphite particles after the reaction is reduced to about 770℃; the once-coated graphite particles flow into the first reaction material reservoir 3-5 from the first reaction material disperser 3-4, the first reaction fluidization loosening air preheating assembly 3-9 is preheated to about 800℃ high-purity nitrogen, which is introduced into the first reaction material reservoir 3-5 at a flow rate of 320 NL / h and causes the graphite particles in it to be in a loose fluidized state; the first reaction heater 3-2 is turned on, and the once-coated graphite particles in the lower dense phase section of the first reactor 3-1 and the first reaction material reservoir 3-5 are re-heated to 950±5℃; the first reaction fluidization loosening air F2 passes through the first reaction material reservoir 3-5, flows upward into the first reactor 3-1 from the first reaction material disperser 3-4, and forms a dense phase section in the lower part of the reactor; the fluidization loosening air mixed with the H2 generated in the reaction process flows out of the first reactor from the first reaction gas phase outlet line 3-10, and then enters the first reaction cyclone 1-8 in the gas-solid separation zone I along the first reaction cyclone line 7 for gas-solid separation;

[0085] The second reaction zone uses the same raw materials and feed amounts, operating conditions, and operating procedures as the first reaction zone;

[0086] The sampling analysis by the solid product sampling assembly 6-2 shows that the thickness of the amorphous carbon on the surface of the twice-coated graphite particles does not meet the technical requirements, and needs to be coated again. The second reverse heater 4-2 and the circulation control valve 6-6 are opened, and the discharge control valve 6-3 is closed. The lifting air preheating assembly 6-1 is used to preheat the lifting air F7 to 790±5℃, and the unqualified twice-coated graphite particles are sent into the gas-solid separation zone by the lifting pipe 6-6 and the lifting air F7, and are separated by the circulating material cyclone 1-5.

[0087] The operating temperature of the gas-solid separation zone I is controlled to be 790±5℃, and the operating pressure is the same as the pressure of each reaction zone. The ultra-fine graphite particles separated from the first reverse cyclone 1-8, the second reverse cyclone 1-7, the circulating material cyclone 1-5 and the filter 1-3 are sent into the intermediate tank 2-2 along the separation zone discharge pipe, and continue to participate in the coating reaction.

[0088] In this embodiment, the same coating raw material is used in two reactors in series for two circulation processes, and a total of 24.43 kg of graphite particle coating products meeting the requirements are obtained.

[0089] In this embodiment, the same coating raw material is used in two reactors in series for two circulation processes, and a total of 24.43 kg of graphite particle coating products meeting the requirements are obtained.

[0090] Specifically, the solid S to be coated is graphite particles with a D50 particle size of 8 μm. The first reverse coating raw material F1, the second reverse coating raw material F3 and the third reverse coating raw material F5 all use a mixture of acetylene (C2H2) and hydrogen (H2), and the molar ratio of acetylene is 0.15. The first reverse fluidizing and loosening air F2, the second reverse fluidizing and loosening air F4, and the third reverse fluidizing and loosening air F6 are high-purity nitrogen with a purity of 99.999%. The stripping air is ordinary nitrogen with a purity of 99.9%.

[0091] The first reverse gas phase valve 7-1, the second reverse gas phase valve 8-1 and the third reverse gas phase valve 9-1 are opened.

[0092] 50 kg of graphite granules are added to intermediate tank 2-2 along solid granule filling line 2-1. Intermediate tank heater 2-4 is turned on to preheat the graphite granules in intermediate tank 2-2 to 950±5℃. Feed control valve 2-4 is opened, allowing the preheated graphite granules to enter the first reactor 3-1 of the first reaction zone I at a rate of 10 kg / h. First-reaction coating feedstock F1, preheated to 750±3℃ by first-reaction feedstock preheating component 3-9, enters the bottom of the first reactor from first-reaction distributor 3-3 at a flow rate of 2000 NL / h. C2H2 gas rises along the reactor, contacts the descending hot graphite granules, and undergoes a chemical reaction. C2H2 decomposes into H2 and amorphous carbon at high temperature, and the amorphous carbon coats the surface of the graphite granules, forming a carbon coating layer. The bed center temperature of the first reactor 3-1 is controlled at 780±5℃, and the operating pressure is controlled at 70±2 kPaG. Because this reaction is endothermic, the temperature of the graphite granules decreases after the reaction. The temperature is approximately 780℃. The once-coated graphite particles flow from the primary reactor material disperser 3-4 into the primary reactor storage tank 3-5. High-purity nitrogen gas, preheated to approximately 800℃ by the primary reactor fluidization loosening air preheating component 3-9, is introduced into the primary reactor storage tank 3-5 at a flow rate of 300 NL / h, placing the graphite particles in a loose fluidized state. The primary reactor heater 3-2 is then activated, allowing the once-coated graphite particles from the lower dense phase section of the first reactor 3-1 and the primary reactor storage tank 3-5 to pass through. The temperature is raised to 950±5℃; the fluidizing loosening air F2 of the first reactor passes through the first reactor storage tank 3-5 and then enters the first reactor 3-1 from the first reactor material disperser 3-4, causing a dense phase section to form in the lower part of the reactor; the fluidizing loosening air entering the dense phase section of the first reactor mixes with the H2 generated in the reaction process and exits the first reactor from the first reactor gas phase outlet line 3-10, and then enters the first reactor vortex separator 1-8 located in the gas-solid separation zone I along the first vortex guide line 7 for gas-solid separation;

[0093] Open the first plug valve 3-7, and the graphite particles that have been coated once will descend along the first feed pipe 3-6 into the second reactor 4-1;

[0094] The second reaction zone IV and the third reaction zone V use the exact same reaction conditions as the first reaction zone III;

[0095] The operating temperature of gas-solid separation zone I is controlled at 790±5℃, and the operating pressure is the same as that of each reaction zone. The ultrafine graphite particles separated from the first counter-rotating fraction 1-8, the second counter-rotating fraction 1-7, the third counter-rotating fraction 1-6 and the filter 1-3 go down the discharge pipe of the separation zone into the intermediate tank 2-2 to continue to participate in the coating reaction.

[0096] After undergoing three coating reactions, the graphite particles enter the solid material receiving and circulation zone VI through the three-reaction feed pipe 5-6. Sampling and analysis are performed by the solid product sampling component 6-2. The analysis results show that the thickness of the amorphous carbon on the surface of the graphite particles after three coating reactions meets the technical requirements and does not need to be recycled and coated again. The circulation control valve 6-6 is closed and the discharge control valve 6-3 is opened, and all qualified products are transferred into the product tank 6-4.

[0097] In this embodiment, three reactors with the same coating raw material were connected in series and passed through the process in one go, obtaining a total of 54.10 kg of graphite granule coating product that met the requirements.

[0098] Example 4: The multi-stage series-connected downward fluidized bed reaction system comprises four reaction zones connected in series. The first and second reaction zones are used for coating silicon, using the same coating raw materials (methylsilane, SiH4 + hydrogen, H2) and reaction conditions, with a molar ratio of SiH4 to H2 of 0.20. The third and fourth reaction zones are used for coating amorphous carbon, using the same coating raw materials (acetylene, C2H2 + hydrogen, H2) and reaction conditions, with a molar ratio of C2H2 to H2 of 0.20.

[0099] The solid S to be coated is graphite particles with a D50 particle size of 8 μm; the loosening air for the first, second, third, and fourth reverse-fluidization processes is high-purity nitrogen with a purity of 99.999%; the air-lifting air is ordinary nitrogen with a purity of 99.9%.

[0100] Open the gas phase valves on the swirl lines leading to the gas-solid separation zone from each reactor;

[0101] 30kg graphite particles are added into the intermediate tank 2-2 along the solid particle feeding line 2-1, the intermediate tank heater 2-4 is turned on to preheat the graphite particles therein to 720±5℃, and the operating pressure is controlled at 80±3KPaG; the feed control valve 2-4 is opened to make the preheated graphite particles enter the first reactor 3-1 in the first reaction zone at a rate of 10kg / h; the SiH4 coated graphite particles preheated to 380±2℃ by the first reactor raw material preheating assembly 3-9 enter the bottom of the first reactor at a flow rate of 1800NL / h from the first reactor distributor 3-3, the SiH4 gas goes up along the reactor, contacts with the descending hot graphite particles and reacts chemically, the SiH4 is decomposed into H2 and Si at high temperature, and the Si coats the surface of the graphite particles; since the reaction is an exothermic reaction, the bed center temperature of the first reactor 3-1 is controlled at 740±5℃ by reducing the feed temperature and the preheating temperature of the graphite particles, and the operating pressure is controlled at 80±3KPaG; the once-coated graphite particles flow into the first reactor storage 3-5 from the first reactor material distributor 3-4, and the high-purity nitrogen preheated to about 400℃ by the first reactor fluidization loosening air preheating assembly 3-9 is introduced into the first reactor storage 3-5 at a flow rate of 300NL / h to make the graphite particles therein in a loose fluidized state; in order to reduce the temperature of the once-coated graphite particles, the first reactor heater 3-2 is turned off, and the once-coated particles are cooled to 720±5℃ by using high-purity nitrogen;

[0102] The coating raw material, operating conditions and operating process of the second reactor in the second reaction zone are the same as those of the first reactor described above; before the third coating reaction is carried out, the particles after the second coating reaction need to be heated to a temperature required for the third coating reaction, the second reactor fluidization loosening air preheated to 800±5℃ at a flow rate of 300NL / h is turned on, the second reactor heater 3-2 is turned on to preheat the graphite particles after the second coating reaction to 920±5℃; the opening of the second reactor stop valve 4-7 is controlled to make the second-coated particles enter the third reactor 5-1 along the second reactor discharge pipe 3-6 at a flow rate of 10kg / h;

[0103] The three-refluxed coated raw material C2H2 preheated to 750±3℃ by the three-reflux raw material preheating assembly 5-8 enters the third reactor bottom from the three-reflux distributor 5-3 at a flow rate of 2000 NL / h, and the C2H2 gas goes up along the reactor and contacts with the downward graphite particles which have undergone two silicon coating reactions, and the C2H2 decomposes into H2 and amorphous carbon at high temperature, and the carbon coating reaction continues to occur at the periphery of the silicon coating layer to form an amorphous carbon coating layer; the bed center temperature of the third reactor 5-1 is controlled at 800±5℃, and the operating pressure is controlled at 70±2 KPaG; since the reaction is an endothermic reaction, the temperature of the graphite particles after the reaction is reduced to about 790℃; the graphite particles which have undergone once carbon coating flow into the three-reflux storage tank 5-5 from the three-reflux material disperser 5-4, high-purity nitrogen preheated to about 800℃ by the three-reflux fluidization loosening air preheating assembly 5-9 is introduced into the three-reflux storage tank 5-5 at a flow rate of 350 NL / h to make the graphite particles in the three-reflux storage tank 5-5 in a loose fluidization state; the three-reflux heater 5-2 is turned on to reheat the once carbon coated graphite particles in the three-reflux storage tank 5-5 and the lower dense phase section of the third reactor 5-1 to 920±5℃; the three-reflux fluidization loosening air F6 goes through the three-reflux storage tank 5-5 and then goes up from the three-reflux material disperser 5-4 into the first reactor 5-1 to form a dense phase section in the lower part of the reactor; the fluidization loosening air entering the dense phase section of the third reactor mixes with the H2 generated in the reaction process, and then goes out of the third reactor from the three-reflux gas phase outlet line 5-10 and then enters the three-reflux cyclone 1-6 located in the gas-solid separation zone I along the three-cyclone lead line 9 for gas-solid separation;

[0104] The fourth reaction zone uses the same coated raw materials and feed amounts as the third reaction zone, and the operating conditions and operating steps are also the same as the third reaction zone;

[0105] The operating temperature of the gas-solid separation zone I is controlled at 790±5℃, and the operating pressure is the same as that of each reaction zone; the ultra-fine particle size graphite particles separated from the first, second, third, fourth, and filter cyclones go down along the separation zone discharge pipe into the intermediate tank 2-2 to continue to participate in the coating reaction;

[0106] After the silicon coating in the first and second reaction zones and the amorphous carbon coating in the third and fourth reaction zones, the product meets the technical requirements, and there is no need for graphite particle circulation coating, and a total of 32.24 kg of graphite coated products meeting the requirements are obtained in this embodiment.

[0107] The utility model discloses the part of not detailed is prior art, for the person skilled in the art, apparently the utility model is not limited to the details of the above exemplary embodiments, and can realize the utility model with other specific forms without departing from the spirit or basic characteristics of the utility model, therefore, no matter from which point, should be regarded as exemplary, and is non - limitative, aims at including all changes in the meaning and range of equivalent elements in the utility model.

Claims

1. A multi-stage, series flow bed reactor system, characterized by: The gas-solid separation zone, the multi-stage series reaction zone and the solid material receiving and circulating zone are sequentially connected from top to bottom. The gas-solid separation zone has a gas collection chamber, an upper separation chamber and a lower separation chamber from top to bottom, the upper separation chamber is provided with a plurality of filters on the top wall for connecting the gas collection chamber, the lower separation chamber is provided with a plurality of cyclone separators for connecting the upper separation chamber, and the cyclone separators are connected with the gas phase outlets of the multi-stage series reaction zone and the circulating part of the solid material receiving and circulating zone one by one.

2. The multi-zone, series flow reactor system of claim 1, wherein: The top of the gas collection chamber is connected with a tail gas outlet line, and the bottom of the upper separation chamber and the lower separation chamber is provided with a discharge channel corresponding to the feed inlet of the multi-stage series reaction zone.

3. The multi-zone, series flow reactor system of claim 2, wherein: The bottom of the upper separation chamber and the lower separation chamber is inclined from top to bottom, and the lower end of the bottom of the lower separation chamber is provided with a separation zone discharge pipe corresponding to the solid particle charging and preheating zone.

4. The multi-zone, series flow reactor system of claim 1, wherein: The bottom of the upper separation chamber is provided with an upper separation chamber discharge pipe with the discharge port close to the separation zone discharge pipe. The upper separation chamber discharge pipe is attached to the inner side wall of the lower separation chamber, and the lower end of the upper separation chamber discharge pipe is located directly above the upper end of the separation zone discharge pipe.

5. The multi-zone, series flow reactor system of claim 4, wherein: The multi-stage series reaction zone has a reactor and a storage device connected from top to bottom, the reactor is provided with a distributor and a material disperser with an unsealed bottom, the side wall of the distributor is connected with a raw material feeding line, the bottom of the storage device is connected with a loose air feeding line, and the bottom of the storage device is connected with the next stage reaction zone or the solid material receiving and circulating zone through a plug valve.

6. The multi-zone, series flow reactor system of claim 4, wherein: The reactor and the storage device are wrapped with a reaction heater.

7. The multi-zone, series-connected fluidized bed reaction system according to claim 1, characterized by: The reaction heater has a partition heating and temperature control function.

8. The multi-zone, series-connected fluidized bed reaction system according to claim 1, characterized by: The distributor is located at the joint of the material disperser and the reactor.

9. The multi-zone, series flow reactor system of claim 8, wherein: The solid material receiving and circulating zone includes a feeding pipe connected with the multi-stage series reaction zone, a product tank connected with the lower end of the feeding pipe, a solid product sampling assembly, a lifting pipe and a lifting air duct connected with the feeding pipe, wherein the upper end of the lifting pipe is connected with a corresponding cyclone separator, and the outlet of the lifting air duct corresponds to the inlet of the lifting pipe.

10. The multi-zone, series-connected fluidized bed reaction system according to claim 1, characterized by: The gas-solid separation zone and the multi-stage series reaction zone are provided with a solid particle charging and preheating zone. The solid particle charging and preheating zone includes an intermediate tank connected with the discharge channel of the gas-solid separation zone through a top feed inlet, the top feed inlet of the intermediate tank is also connected with a solid particle charging line, the intermediate tank is wrapped with an intermediate tank heater, and the bottom of the intermediate tank is provided with a feed control valve corresponding to the feed inlet of the multi-stage series reaction zone. The multi-stage series reaction zone is arranged in a straight line from top to bottom or in a Z shape.

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