CN-121988239-A - System and method for continuously synthesizing aluminum alkoxide by slurry bed reactor

CN121988239ACN 121988239 ACN121988239 ACN 121988239ACN-121988239-A

Abstract

The invention relates to a system and a method for continuously synthesizing aluminum alkoxide by a slurry bed reactor, which are mainly technically characterized in that metal aluminum powder and C3-C14 alcohol are fully mixed to form mixed slurry of aluminum and organic alcohol and react in the reactor, meanwhile, the reaction process is optimized, aluminum alkoxide is continuously synthesized, the self-catalysis of the aluminum alkoxide is utilized to initiate the reaction, and an exogenous catalyst is not required to be introduced. Compared with the prior art, the self-catalytic reaction of the added metal aluminum powder can be realized, the reaction rate is effectively improved, the alcohol injection supply assembly is introduced at the bottom, reactants are supplemented, meanwhile, impact flow is formed at the lower part of the screen, aluminum layering on the screen continuously vibrates, powder accumulation is prevented from blocking meshes, meanwhile, the suspension state of the powder can be maintained, the metal aluminum can be completely reacted, the heat recovery system is arranged at the top of the reaction, the hydrogen and the alcohol generated in the reaction process are orderly mixed and can be cooled, and the reactor is prevented from bumping.

Inventors

LI CHUNCHENG
ZHOU YONGXIAN
HE QIUPING
ZHANG ZIJIAN
YANG CHUNWEI
ZHANG JIA

Assignees

上海绿强新材料有限公司

Dates

Publication Date: 20260508
Application Date: 20251222

Claims (10)

1. The system for continuously synthesizing aluminum alkoxide by using a slurry bed reactor is characterized by comprising a reactor (1), wherein a heat recovery area is arranged at the upper part in the reactor (1), two groups of parallel staggered guide impellers (2) and spray nozzles (6) communicated with an alcohol condensation reflux pipeline (13) are arranged in the heat recovery area, a slurry reaction area (5) is arranged at the lower part, a screen (7) is arranged at the bottom of the slurry reaction area (5), an alcohol spray nozzle (10) communicated with an alcohol feed pipeline (15) is arranged at the bottom of the screen (7), and a raw material spray nozzle (9) communicated with an aluminum powder alcohol solution slurry feed pipeline (14) is arranged above the slurry reaction area (5); The top of the reactor (1) is provided with a mixed steam pipeline (11), and the mixed steam pipeline (11) is respectively connected with a top hydrogen pipeline (12) and an alcohol condensation reflux pipeline (13) after passing through the heat exchanger (4).
2. The system for continuously synthesizing aluminum alkoxide by a slurry bed reactor according to claim 1, wherein the number of impeller blades of each of the two sets of impellers (2) is 6 to 10, the radial length of the blades is 330 to 450mm, the inclination angle of the blades is 15 to 45 degrees, and the pitch (angular direction) of the blades is 30 to 60 degrees.
3. The system for continuously synthesizing aluminum alkoxide in slurry bed reactor according to claim 1, wherein the reactor (1) has a bottom portion provided with a reactant discharge line (19), and the reactant discharge line (19) is connected back to the reactor (1) through a circulation line; The alcohol feed line (15) is also connected to the alcohol condensate return line (13) via a make-up alcohol feed line (20).
4. The system for continuously synthesizing aluminum alkoxide by using the slurry bed reactor according to claim 1, wherein the number of the spray nozzles (6) is 8-12, and the inward inclination angle of the nozzles is 15-30 degrees; The number of the alcohol spray nozzles (10) is 8, the 8 groups of nozzles are in cross-shaped layout, 4 spray heads are distributed on each group of nozzles, the dip angle of each spray head is 0-45 degrees, and the diameter of each spray head is 0.5-1.5 mm; the mesh number of the screen (7) is 200-350, and the screen is made of stainless steel, fiber or polytetrafluoroethylene.
5. A method for continuously synthesizing aluminum alkoxides using the system of any one of claims 1 to 4, comprising the steps of: s1, after metal aluminum powder and saturated alcohol are fully mixed, the obtained aluminum alkoxide powder slurry is added into a slurry reaction zone (5) of a reactor (1) through a raw material spray nozzle (9), the temperature in the reactor (1) is raised to the boiling state of the saturated alcohol, and a mixed solution of aluminum alkoxide obtained by reaction and unreacted saturated alcohol is discharged from a reactant discharge pipeline (19) at the bottom of the reactor (1); S2, intercepting the metal aluminum powder which is not fully reacted in a slurry reaction zone (5) through a screen (7), continuously supplementing saturated alcohol through an alcohol spray nozzle (10) in the reaction process to promote reaction balance, and simultaneously forming impact flow at the lower part of the screen (7) by the supplemented saturated alcohol to ensure that aluminum on the screen (7) continuously vibrates in a layered manner, so that powder accumulation is prevented from blocking meshes, a reaction liquid is in a fluidization state-like process through the saturated alcohol sprayed out of the alcohol spray nozzle (10), and the suspension state of the powder is maintained to ensure that the metal aluminum is fully reacted; and the steam generated by the S3 reaction is guided by the guide impeller (2), and is subjected to heat exchange with alcohol reflowed by the alcohol condensation reflow pipeline (13) in the heat recovery area, so that the alcohol is condensed and reflowed to the slurry reaction area (5), and the explosion boiling in the reaction process is avoided.
6. The method for continuously synthesizing aluminum alkoxide according to claim 5, wherein the saturated alcohol is one of aliphatic alcohols of 3 to 14 carbon atoms, the particle size of the metal aluminum powder is 100 to 400 meshes, the mass ratio of the metal aluminum powder to the saturated alcohol is 1 (4 to 20), the temperature of the reactor (1) is 95 to 180 ℃, and the pressure is 0.12 to 0.30 MPa.
7. The method for continuously synthesizing aluminum alkoxide according to claim 5, wherein the mass ratio of the amount of the saturated alcohol added in the step S2 to the amount of the raw material added in the step S1 is 0.7 to 1.0:1.
8. The method for continuously synthesizing aluminum alkoxide according to claim 5, wherein the volume ratio of the slurry reaction zone (5) to the reactor (1) is 1 (5-6).
9. The method for continuously synthesizing aluminum alkoxide according to claim 5, wherein steam generated by the reaction is guided in the reactor by two groups of guide impellers (2) to form an S-shaped air channel, and the air flow rate is 0.5-3 m/S; the jet flow of the spray nozzle (6) is 0.4-1.0L/min; The spraying rate of the alcohol spray nozzle (10) is 1.0-10.0 m/s.
10. The method for continuously synthesizing aluminum alkoxide according to claim 5, wherein a part of the reaction product discharged from the reactant discharge line (19) is circulated and flowed into the reactor (1) by the circulation pump (3) to react, and the ratio of the circulation material to the reaction effluent is 1 (3-5).

Description

System and method for continuously synthesizing aluminum alkoxide by slurry bed reactor Technical Field The invention relates to the field of aluminum alkoxide synthesis, in particular to a system and a method for continuously synthesizing aluminum alkoxide by a slurry bed reactor. Background Aluminum alkoxide (or aluminum alkoxide) is an important chemical intermediate, and has wide application in the fields of high-purity aluminum oxide ceramic precursors, medical synthesis, catalysts, carrier materials, semiconductor material preparation and the like. Currently, the main processes for the industrial production of aluminum alkoxides include ziegler (substitution reaction of aluminum alkyls with alcohols) and direct alcoholysis of metallic aluminum with alcohols. The Ziegler-Natta process can produce high purity product, but has the advantages of harsh reaction conditions, difficult process control, extremely sensitive environment humidity and less adoption at present. Therefore, the synthesis of aluminum alkoxides by reacting metallic aluminum with alcohols is the dominant process route. However, the reaction is a strong exothermic process, and simultaneously, along with hydrogen generation, heat is easy to accumulate in a reaction system, so that alcohol steam and hydrogen are azeotroped, a 'bumping' phenomenon is caused, and the safety of equipment and the process stability are challenged. To cope with the above problems, various improvements have been proposed in the prior art. For example, patent CN112898127B discloses a method for continuously preparing high purity aluminum isopropoxide in a microchannel reactor, by adding a catalyst and arc-shaped design of the inner wall of the reactor, turbulent contact of aluminum particles with alcohol liquid is promoted, so as to prolong the reaction time and increase the reaction rate. In the patent CN111187147A, a kettle reactor is used for continuously synthesizing aluminum alkoxide, and alcohol steam is refluxed by an external condenser, so that hydrogen separation and alcohol recycling are realized. Patent CN113694851B proposes to prevent the bumping problem through real-time supervision reation kettle and the pressure differential of environment, in time clears up the condensation pipeline, avoids pressure accumulation to lead to bumping. U.S. patent No. 4590289 designs a reactor structure with a wide upper part and a narrow lower part, and sectional feeding of alcohol from different positions to inhibit the material flushing risk caused by bumping. However, the above prior art mostly uses bulk or granular aluminum as a raw material. Although such aluminum sources can moderately slow the exothermic strength of the reaction, their limited specific surface area results in slow initiation of the reaction and low overall production efficiency. Although the initiation can be promoted by adding catalysts such as aluminum chloride, mercury chloride and the like, impurity ions can be introduced, and the difficulty and cost of subsequent separation and purification are increased. In contrast, the adoption of aluminum powder as a raw material can obviously increase the reaction interface and accelerate the reaction initiation and progress, but the aluminum powder is easy to agglomerate and accumulate in use, so that the alcohol solution is difficult to fully contact with the aluminum powder, and the reaction efficiency and the conversion rate of the aluminum are possibly reduced. Although the US2845447 tries to use aluminum powder as raw material, the aluminum utilization rate is reduced by adopting a proportioning mode of insufficient alcohol amount to avoid bumping. In summary, how to avoid using external catalysts, not only can utilize the high reactivity of aluminum powder, but also can effectively solve the problem of bumping caused by accumulation, uneven contact and concentrated reaction heat, thereby realizing the efficient, safe and continuous production of aluminum alkoxide, and still being a technical problem to be solved in the field. Disclosure of Invention The invention aims to overcome the defects of the prior art and provide a system and a method for continuously synthesizing aluminum alkoxide by using a slurry bed reactor, which realize the efficient, safe and continuous production of aluminum alkoxide. The invention can be realized by the following technical scheme that the system for continuously synthesizing aluminum alkoxide by a slurry bed reactor comprises a reactor, wherein the upper part in the reactor is provided with a heat recovery area, the heat recovery area is provided with two groups of guide impellers which are staggered in parallel and a spray nozzle communicated with an alcohol condensation reflux pipeline, the lower part is provided with a slurry reaction area, the bottom of the slurry reaction area is provided with a screen, the bottom of the screen is provided with an alcohol spray nozzle communicated with an alcohol feed pipel