Model For Propylene Polymerization Research Articles

The influence of catalyst flow rate and superficial gas velocity on the modified two‐phase model for propylene polymerization in a gas‐phase fluidized bed reactor

AbstractOlefin polymerization, especially of propylene in gas‐phase fluidized bed reactors, is increasingly prevalent because of its ability to handle the continuous process, among other advantages. The challenge for modelling this process is solving the high nonlinearity phenomena in such a system. This research studies the influence of catalyst flow rate and superficial gas velocity on the modified two‐phase model. The catalyst flow rates were set at 1 × 10−4, 2 × 10−4, and 3 × 10−4 kg/s, while the superficial flow rates were set at 0.35, 0.5, and 0.65 m/s. Production rate, reactor temperature, and heat‐loss flow rate were found to be proportional to catalyst flow rate and inversely proportional to superficial gas velocity. Heat loss through the fluidized bed wall had an influence only on the reactor temperature. Finally, predicted reactor temperatures corresponded closely to the pilot plant data, with deviations smaller than 0.5%.

Modeling of propylene polymerization with long chain branching

Abstract A kinetic model has been proposed to describe the propylene polymerization process with long chain branching for a twin catalyst system to fit the experimental evolution of molecular weights, polydispersity index of atactic polypropylene, isotactic polypropylene and the grafting density at different catalyst and cocatalyst concentrations. Kinetic parameters are estimated by real coded genetic algorithm (an evolutionary optimization technique) from experimental data available in open literature. The validated model has the capability of predicting the branching density as a function of catalyst addition pattern, catalyst ratios and copolymerization time. Further, the validated model has been used to calculate the ‘molecular weight long chain branching distribution’. Parametric sensitivity study has been conducted to analyze the effect of kinetic parameters on the long chain branching formation and other molecular properties of the polymer.