Detailed Molecular Structure Modeling – A Path Forward to Designing Application Properties of ldPE

This paper describes a step on the ambitious aim to design application properties of ldPE by first simulating the detailed molecular structure of a high-pressure tubular reactor product. The reactor of a certain configuration produces under well-defined operating conditions. The next step is to correlate the structure with the application properties. Finally, the sequence will be reversed in order to deduce the operating conditions, which lead to the desired product quality. Two-dimensional distributions, in molecular weight and branching frequency, as well a two compartment models with a core and a shell stream were simulated and compared with experimental results. Therefore, CFD simulations were carried out to discretize the reaction medium. Samples were taken from both pilot and commercial plants. The TREF-SEC analytical method was successfully applied in order to measure the microscopic structure of the material. The tremendous numerical problems were solved with the help of the software PREDICI.