The production process of PP(4)

Gas phase bulk method

Process features: (1) no solvent is introduced into the system, and propylene monomer is polymerized in gas phase in the reactor; (2) the process is short, the equipment is few, the production is safe, and the production cost is low; (3) the polymerization reactor includes fluidized bed (carbon union / shell unipoi process), vertical stirred bed (BASF novolen process) and horizontal stirred bed (Amoco / El Paso process).

The typical representative of gas phase bulk method is Unipol gas phase process of Dow Chemical Company. Unipol gas-phase polypropylene process is a kind of gas-phase fluidized bed polypropylene process developed by UCCP and shell in the 1980s. It is a successful process of transplanting the fluidized bed process applied in polyethylene production into polypropylene production. The process uses a high-efficiency catalyst system, the main catalyst is a high-efficiency carrier catalyst, and the cocatalyst is triethyl aluminum and electron donor.

The Unipol process is simple, flexible, economical and safe; the process can produce a full range of products including homopolymers, random copolymers and impact copolymers with only a few equipment, which can adjust the operating conditions in a large operating range and keep the product performance uniform. Due to the small number of equipment used, the maintenance workload is small and the reliability of the device is improved. Due to the limitation of the reaction dynamics of the fluidized bed and the low operating pressure, the material storage in the system is reduced, which makes the process safer than other processes, and there is no danger of overpressure of the equipment when the accident is out of control.

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