Modeling Of Propylene Polymeriation

Propylene polymerization on heterogeneous catalyst belongs to anion coordination polymerization, which kinetic mechanism is very complex and have not been made clear completely yet. As the polymerization processes are various and the used catalysts are different, it is important to build mathematical models and conduct simulation on computer, which can provide basis for the design of optimization and control system of polymerization reactors.A steady model of industry polypropylene reactors is developed, which comprises mass balance equations, energy balance equations, vapor-liquid phase balance equations and reaction kinetic equations, can predict the important process variable, such as productivity, slurry density, liquid hydrogen concentration, the fraction of catalyst in macroparticle. Not only the key results are computed, but also the steady-state behavior of the reactor is interpreted and analyzed theoretically through the energy balance. The kinetic parameters come from the articles and are corrected in the calculation.The dynamic model is also based on mass balance, energy balance and vapor-liquid phase balance. By computer simulation, the change trend of the key process variables against the reactive time is calculated and the influence on the slurry density of continuous stirred tank reactor imposed by operational variables is 'Studied, which laid basis for the optimal design of advanced control system and grade transition process.This paper also develops a dynamic model of polypropylene molecular weight distribution and predicts the mean number average molecular weight, mean weight average molecular weight and disperse index. By computer simulation, the influence on the molecular weight of polypropylene by various process parameters is analyzed, which provides basis for the design of qualities control system for Propylene polymerization.