Continuous Prepolymerization Technology for Propylene Polymerization

At present, in most of the gas-phase propylene polymerization processes, catalyst is directly added into reactor without any pre-treatment. As a result, too many fines and agglomerations are formed in the polymer particles, which play a negative influence on the stability of plant operation. Batch prepolymerization technology leaves high amount of residual solvent in the final products, which limits their applications in the fields of food packaging, medical supplies, and so on.
The problems mentioned above can be solved effectively by using SINOPEC’s technology — continuous prepolymerization technology for gas-phase polymerization of propylene. For the processes without prepolymerization unit, application of this technology will bring greatly improvement on the operation stability of the plant and greatly increase of the catalytic activity, and reduce the production cost. For the processes using batch prepolymerization technology, application of continuous prepolymerization technology can not only eliminate the residual solvent in the final products, but also decrease the production cost because solvent is no longer used.
In the continuous prepolymerization technology, the operating pressure and operating temperature in the reactor are 2.5-3.6 MPa and 0-30 ºC respectively, and the mean residence time of the catalyst in the reactor is 5-30 min. The detailed process conditions depend on the practical situation of the plant.