Post-processing method of polypropylene powder

Abstract

The invention discloses a post-treatment method for polypropylene powder, which belongs to the field of petrochemical industry. For the existing polypropylene post-treatment process, "the polypropylene powder that leaves the polymerization system and undergoes preliminary gas / solid separation or enters the dryer, is indirectly heated by steam and nitrogen, removes hydrocarbons in the powder, and then enters the steam Nitrogen and water vapor are passed into the steamer to deactivate the catalyst; or enter the degassing chamber, and nitrogen containing water vapor is passed into the degassing chamber to improve: instead of passing nitrogen into the dryer, water vapor is passed into the dryer, and the It is transformed into a steam dryer that recovers hydrocarbons and deactivates the catalyst. The polymer after removing hydrocarbons enters the steamer (or degassing chamber, the same below), and nitrogen without water vapor is added into the steamer to deactivate the steam. The steamer is transformed into a dehumidifier for removing water vapor in the powder. The invention can completely recover the hydrocarbons leaving the polymerization system in an economical way, reduce unit consumption and energy consumption, and completely solve the problem of environmental protection.

Description

technical field [0001] The invention belongs to the field of petrochemical industry. Background technique [0002] The content of the present invention relates to a method for deactivating, removing and economically recovering the hydrocarbons carried in the powder in the process of producing polypropylene, the residual catalyst in the polypropylene powder after leaving the polymerization reactor. [0003] As we all know, after the synthesis of polypropylene, the polypropylene powder leaving the polymerization system carries a certain amount of hydrocarbons, some of which are dissolved in the polymer and some are free. The purpose of post-treatment of polypropylene powder is to remove these The carried hydrocarbons are removed, and at the same time, the residual catalyst (including catalyst and aluminum alkyl) in the powder is deactivated. The above process of removing hydrocarbons is generally called degassing or devolatilization (or drying), and the process of decomposing...

AI Technical Summary

Problems solved by technology

But still can not completely solve the problem of reducing unit consumption

Owing to not feeding nitrogen in the drier, the hydrocarbons carried when the polypropylene powder enters the steamer by the drier are compared with Japanese Patent Laid-Open No. 58-157807, No. 56-139520 (Mitsui Oil & Chemical) when passing nitrogen in the drier. When the dryer enters the steamer, it carries more hydrocarbons, which brings environmental problems when the exhaust gas of the steamer is discharged.

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