CN-122015431-A - Low-temperature closed-loop circulating fluidization drying system

CN122015431ACN 122015431 ACN122015431 ACN 122015431ACN-122015431-A

Abstract

The invention discloses a low-temperature closed-loop circulating fluidized drying system, which relates to drying of dimethyl azodiisobutyrate and aims to solve the problems that in the prior art, the dimethyl azodiisobutyrate is high in drying temperature and easy to form a molten state, and the drying efficiency is low and the drying quality cannot be ensured due to the fact that crystal forms are damaged. The vertical boiling fluidization device in the system is used for drying materials, the dust removal device is used for efficiently intercepting solid particles in nitrogen, the low-temperature cooling recovery device is used for spraying low temperature water and absorbing organic solvents in nitrogen, the micro-thermal adsorption device is used for removing moisture in nitrogen and obtaining low-temperature dry nitrogen, the low-temperature dry nitrogen is recycled to the vertical boiling fluidization device, the drying temperature of the wet product of the dimethyl azodiisobutyrate is controlled to be 15 ℃ or below, the drying efficiency of the wet product of the dimethyl azodiisobutyrate is greatly improved through the drying system, and the quality of the wet product of the dimethyl azodiisobutyrate is also greatly improved.

Inventors

LI QIU
YIN KEMING
JIANG YU
TANG DAJIA
WANG JIE
MA YI

Assignees

四川能投永立化工有限责任公司

Dates

Publication Date: 20260512
Application Date: 20241108

Claims (6)

1. A low-temperature closed-loop circulating fluidization drying system is characterized by comprising a vertical boiling fluidization device, a dust removal device, a low-temperature cooling recovery device and a micro-thermal adsorption device which are sequentially arranged and form a closed loop; The vertical boiling fluidization device comprises a fluidized bed body, wherein a feed inlet is formed in one side of the upper side surface of the fluidized bed body, a material distributing and dispersing mechanism is arranged in the fluidized bed body and comprises a connecting rod arranged in the fluidized bed body, a plurality of material distributing plates are uniformly distributed on the outer side surface of the connecting rod, gaps are formed between the material distributing plates, the connecting rod is obliquely connected with two ends, a vibration device is arranged, and a material blowing mechanism is arranged in the fluidized bed body and lower than the material distributing and dispersing mechanism; the dust removing device comprises a box body, an in-box partition plate for dividing the box body into two or more chambers, an ash bucket and an ash discharging valve which are arranged at the bottom of the chambers, a filtering system and an ash removing system which are arranged in the chambers, and a top cover which is arranged at the top of the chambers, wherein the chambers are respectively provided with an air inlet pipe and an air outlet pipe; The low-temperature cooling recovery device sprays an absorbent into the nitrogen, the absorbent absorbs the organic solvent in the nitrogen, and the nitrogen after the organic solvent is removed enters the micro-thermal adsorption device; The micro-thermal adsorption device comprises an input subsystem, an output subsystem and two heating filter devices with the same structure, wherein the input end of the input subsystem is connected with the output end of the air compressor, the output end of the input subsystem is respectively communicated with the two heating filter devices, the output ends of the two heating filter devices are communicated with the input end of the output subsystem, the output end of the output subsystem outputs to air utilization equipment, and the two heating filter devices alternately work.
2.A low-temperature closed-circuit circulating fluidized drying system is characterized in that a blowing mechanism comprises a fluidized bed body, a plurality of inclined scrapers are uniformly distributed on the front side and the rear side of the fluidized bed body, shafts are rotatably arranged between the scrapers on the front side and the rear side of the fluidized bed body, a drum with hollowed surfaces is arranged between the shafts, a motor is arranged on one side of the fluidized bed body and at the position corresponding to one shaft, one end of the motor, which extends out of the fluidized bed body, is fixedly connected with one end of the shaft, the other end, which extends out of the fluidized bed body, of the shaft, is sleeved with gears meshed with each other, through holes are formed in the other end, which extends out of the fluidized bed body, the through holes are matched with the drum, connecting pipes are inserted in the through holes, spiral air outlet pipes are formed in one end, which extends into the drum, air outlet holes are uniformly distributed on the outer side of the fluidized bed body, a plurality of air outlet holes are uniformly distributed between a material separating and blowing mechanism, pipelines are formed in the air outlet holes, the pipelines are formed in the air outlet holes, a cyclone is formed in the air outlet pipe, a cyclone is connected with a cyclone, a material blowing mechanism is arranged in the fluidized bed body, and is arranged below the blowing mechanism, the cyclone is matched with the discharging end, and the discharging mechanism is discharged, the connecting pipe is arranged, a connecting pipe, and a spiral supporting leg is arranged, and a vibration reducing mechanism is arranged below the vibration reducing mechanism.
3. The low-temperature closed-loop circulating fluidized drying system of claim 1, wherein the temperature of low-temperature circulating nitrogen blown into the vertical boiling fluidization device is not more than 15 ℃, and the material to be dried in the vertical boiling fluidization device is 0-5 ℃ of crystallized material.
4. The low-temperature closed-loop circulating fluidized drying system according to claim 1, wherein the absorbent sprayed in the low-temperature cooling recovery device is low-temperature water at 5 ℃, and the absorbent absorbs the organic solvent to form water-saturated nitrogen, and the temperature of the water-saturated nitrogen is 5-8 ℃.
5. A low-temperature closed-circuit circulating fluidized drying system according to claim 1, wherein the low-temperature circulating nitrogen with dew point lower than-40 ℃ is obtained after the nitrogen is dried by the micro-thermal adsorption device, and is recycled to the vertical boiling fluidization device after being regulated to 15 ℃.
6. The low-temperature closed-circuit circulating fluidized drying system of claim 1, further comprising an induced air device, wherein the induced air device is positioned in a closed loop consisting of a vertical boiling vibration fluidization device, a dust removal device, a low-temperature cooling recovery device and a micro-thermal adsorption device, and nitrogen is driven to circularly flow in the closed loop by an induced air fan of the induced air device.

Description

Low-temperature closed-loop circulating fluidization drying system Technical Field The invention belongs to the technical field of chemical product production, relates to drying of dimethyl azodiisobutyrate, and particularly relates to a low-temperature closed-loop circulating vertical fluidized bed drying system for drying dimethyl azodiisobutyrate. Background Dimethyl azodiisobutyrate is an important free radical initiator and is mainly used for polymerization of olefin, acrylic acid and esters thereof, and is used for polymerization of styrene to obtain polymer containing ester end groups and can be hydrolyzed to generate a product containing carboxyl end groups. Dimethyl azodiisobutyrate belongs to heat-sensitive materials, is easy to decompose at high temperature, has a low melting point and is reported in literature to have a melting point range of 22-28 ℃. The invention with the application number 201811386205.2 also discloses a preparation method of the dimethyl azodiisobutyrate, which comprises the steps of firstly adding 2,2' -azobisisobutyronitrile, methanol and dichloroethane into a reactor with stirring and reflux devices, starting stirring, slowly dripping thionyl chloride under cooling, controlling the material temperature and keeping the temperature for reaction, dripping cold water after the reaction is finished for hydrolysis reaction, standing for first layering after the hydrolysis reaction is finished, washing an organic phase obtained after the first layering with water and carrying out second layering, carrying out reduced pressure distillation on the organic phase obtained after the second layering until dichloroethane is completely distilled and recovered, and cooling the liquid azobisisobutyrate dimethyl ester at a low temperature to obtain a white solid azobisisobutyrate dimethyl ester product, wherein the content (HPLC) of the white solid azobisisobutyrate dimethyl ester product is more than 98%, and the yield is 85-95%. The method uses cheaper thionyl chloride to replace hydrogen chloride gas, the thionyl chloride is in a liquid state at normal temperature, the speed and the dosage are convenient to control during dripping, and the reaction time is shortened to 6 hours. As in the above patent, prior art reports have focused on improving the synthesis of dimethyl azodiisobutyrate. For example, the invention patent with the application number 201610526787.4 discloses a synthesis method of dimethyl azodiisobutyrate, which comprises the steps of (1) condensing, adding azodiisobutyronitrile, methanol and isophorone into a reaction container, adding phosphorus trichloride solution for reaction, centrifuging to obtain azoimine methyl ether hydrochloride solid material, (2) hydrolyzing, adding pure water into a hydrolysis container, adding azoimine methyl ether hydrochloride solid material into the hydrolysis container for hydrolysis, (3) phase separation, putting the hydrolyzed material liquid into a phase separation container, carrying out phase separation by using a phase transfer agent cetyl trimethyl ammonium chloride, (4) recrystallizing, and (5) drying. The invention also relates to a synthesis method thereof, and the process route and the raw materials are optimally designed, so that the raw materials are environment-friendly and nontoxic, the reaction is stable and easy to control, and the safety of the reaction is greatly improved. In the drying aspect, the method is simply described as that the dimethyl azodiisobutyrate wet product is placed in a drying chamber to be dried for 24 hours, and the drying temperature is less than or equal to 25 ℃. In the prior art, the drying of the dimethyl azodiisobutyrate is carried out in a drying chamber, but the drying time of the drying method is long, the selected drying temperature reaches the melting point temperature of the dimethyl azodiisobutyrate, the product is extremely easy to form a molten state, the crystal form is damaged, the solvent carried by the wet product is coated in the molten body and is difficult to remove, the drying efficiency is low, and the drying quality is difficult to ensure. In addition, the drying mode of the drying chamber generally requires manual transportation or auxiliary mechanical transportation of wet solid materials into and out of the box body, the sealing performance in the transportation process is poor, the organic solvent in the wet product can volatilize to form an unorganized exhaust gas, the environment is polluted, the manual labor intensity is high, the operation environment is poor, and the equipment treatment capacity is low. Disclosure of Invention The invention aims to solve the problems that in the prior art, dimethyl azodiisobutyrate is high in drying temperature, a molten state is easy to form, a crystal form is damaged, the final drying efficiency is low, and the drying quality is difficult to ensure, and provides a low-temperature closed-loop circulating fluidized drying system. T