Mathematical model and parameter estimation for gas-phase ethylene/hexene copolymerization with metallocene catalyst

作者：Kou B; McAuley KB^*; Hsu JCC; Bacon DW

来源：Macromolecular Materials and Engineering, 2005, 290(6): 537-557.

DOI：10.1002/mame.200400392

• estimability
• gas-phase polymerization
• metallocene
• modeling
• parameter estimation
• polyethylene

Models were developed to simulate gas-phase ethylene/hexene copolymerization using a silica-supported (BuCp)(2)ZrCl2 catalyst in a semi-batch laboratory reactor. The models are able to predict ethylene consumption rate, gas composition drift during the experimental runs, as well as I number-and weight-average molecular weight, and short-chain branching levels, and triad sequence distributions of copolymer removed from the reactor at the end of each run. A single-site model was first developed, but it failed to accurately predict the molecular weight data and its distribution. Sequentially, a two-site model was built to improve model predictions. Parameter estimability analysis was performed to guide model simplification and to ensure that the Parameter estimation problem would be well conditioned. After model simplification, which reduced the number of unknown parameters from 55 to 37, the parameters were estimated and good fitting of most experimental data was obtained. The simplified two-site model was validated using the data from four extra experimental runs, which were not employed in the parameter estimation process. Most of the model predictions fall within the 95% confidence intervals of the experimental data.

• 出版日期2005-6-24