Method for continuously drying polycarbonate

Abstract

The invention belongs to the technical field of drying, and relates to a method for continuously drying polycarbonate, polycarbonate powdery materials are firstly fed into a pneumatic drying accelerator, superheat steam is simultaneously fed, in a pneumatic drying bushing, the polycarbonate powdery materials and the superheat steam concurrently flow forwards, are subjected to heat and mass transfer, and most solvent and water removal to complete the flow drying; then, the materials are mixed up with the steam flow to enter a cyclone drier, the materials and the steam do rotational motion along the inner wall to be subjected to fierce mass and heat transfer, then enter a cyclone separator to realize gas-solid separation for completing the cyclone drying; and the gas which is separated by the cyclone separator enters a solvent recovery system after being filtered by a bag-type dust collector, and the materials enter a primary fluidized bed to be mixed with high-temperature dry air, are subjected to full fluidization and heat transfer to remove the water content, enter a secondary fluidized bed to be cooled to normal temperature, and then enter the next process. The method has a simple technology, is easy to control in operation, has high thermal efficiency, saves energy sources, is environment-friendly, and has a good drying effect, large solvent recovery amount and obvious benefits.

Description

Technical field: [0001] The invention belongs to the technical field of drying, and relates to a new process for desolventizing, dehydrating and hot air dehydrating polycarbonate by using steam, in particular to a continuous drying method for polycarbonate. Background technique: [0002] Usually, polycarbonate powder materials contain 15-35% of water and low boiling point solvents such as dichloromethane, dichloroethane, etc., and these water and solvents need to be removed during the drying process to ensure the content of the material product. The water content is below 500ppm and the good performance of polycarbonate; in addition, the low boiling point solvent needs to be recycled, which can not only save costs, but also help protect the environment. Chinese patent CN200610045528.6 uses high-temperature air as the heating and conveying medium, respectively adopts pulsed airflow drying and fluidized bed drying to dry chlorinated polyethylene, the former removes surface wat...

AI Technical Summary

Problems solved by technology

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art, seek to design and provide a polycarbonate drying process with high thermal efficiency, low equipment investment, and continuous operation, using casing airflow drying, cyclone drying and fluidized bed drying The combination of three methods realizes the drying function; the airflow drying adopted has the dual functions of drying and transportation. The drying pipe is a casing type, and the superheated steam is used to transport and directly heat the material in the pipe to realize the airflow drying. Heating the material strengthens the heat transfer effect, facilitates solvent recovery, and overcomes the problem of pipeline blockage caused by condensation of the feeding material; the cyclone dryer reduces the pressure drop and failure rate during the airflow drying process, and completely removes the solvent in the material The removal is clean, and the length of the airflow drying sleeve is shortened under the condition of ensuring material transportation, which is suitable for continuous large-scale production; these two drying methods are mainly to recover solvent and remove surface water, while the deep drying of water is carried out in a fluidized bed The fluidized bed drying adopts the method of hot air drying and cooling two-stage fluidized bed in series, which can ensure the moisture content and temperature requirements of the material product drying, and effectively use energy to save costs

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