Numerical Analysis of Industrial Styrene Polymerization in Nonideal Tower Reactors

An integrated model combining computational fluid dynamics (CFD) with polymerization kinetics was developed to investigate the industrial styrene thermal polymerization process. The comprehensive kinetic model was coupled with the CFD model by user-defined function (UDF) codes based on the method of moments. Meanwhile, a simulation based on the ideal reactor model was conducted. The results predicted by CFD, including the monomer conversion, molecular weight, and molecular weight distribution described by Flory’s distribution, compared satisfactorily with the plant data and exhibited higher accuracy than those of the ideal reactor model. A higher reaction temperature and a lower volume flow rate result in a higher monomer conversion and a wider molecular weight distribution. The increase of rotational speed of helical ribbon impellers improves the mixing efficiency and uniformity of species concentration in the stirred sections. The CFD model could provide valuable guidance for the optimization of operation conditions and the design of nonideal reactors.