SOLID STATE POLYMERIZATION OF PET IN FIXED BED REACTOR
Qiu Gao, Shi Weizhen, Lu Yuande, Huang Nanxun, Tang Zhilian(China Textile University)Yang Jinkui, Cai Yuzhong, Wang Weimin (Shanghai No.14 Chemical Fibre Plant)
The PET Solid State Polymerization was studied in a fixed bed reactor with nitrogen, as carrying gas, flowing through it. In order to avoid sticking between chips, prepolymerization had been done at a temperature below the sticking point for certain time before the SSP happened at high temperature. The kinetics of PET SSP in a single chip was appropriately simulated with a model combining diffusion rate with reaction rate. The model indicates that the SSP reaction rate from the core to the surface of the chip increases steadily. This is due to gradual reduction of the concentrations of byproducts such as ethylene glycol and water.The effects of the reaction temperature, the concentration of byproducts in the inert carrying gas stream and the particle size on the SSP reaction can also be explained by using this model.