Simulation and optimization of the molecular weight distribution in a non-ideal polymerization reactor

Molecular weight distribution (MWD) is essential for describing the microstructural quality of a polymer. In the past decade, the simulation and optimization of the MWD of a polymerization process have received considerable attention. However, most studies are limited to ideal reactors, such as CSTRs. However, in large-scale industrial reactors, imperfect mixing often leads to a non-uniform distribution. The commercial software Fluent is used in this study to simulate free radical polymerization by the method of moments and computational fluid dynamics (CFD). An interface is designed in-house to extend the simulation to MWD calculation. Given a specific MWD curve as the target, process optimization is performed by combining CFD and MWD calculations in the in-house developed interface between C language and Fluent. A non-ideal tubular reactor is demonstrated for the low-density polyethylene process.