Process Analysis And Simulation Of Polypropylene Production In A Plant

At present, more than half of the production capacity of polypropylene in China is produced by the Spheripol-loop technology of HIMONT Co. Therefore, it is of great importance to carry out simulation and mathematical modeling of the process in order to solve the academic or technological problems involved therein and to further enhance the development and economic benefits of the technology in our nation.In this paper, first, a detailed analysis is presented to ascertain those factors which could affect the manufactures and the characteristics of the manufacture process in view of the practical situation. Based on the analysis, an one dimensional continuous plug-flow model for the polymerization in the loop reactor is set up. The model can be used to predict the distributions of parameters of interest in the inner of the loop reactor along the axial direction. Comparison of the model results with the data taken on line yields satisfactory agreement. Besides, the results showed that the reactor system can be modeled as a CSTR, while the flow in the reactor is strictly plug-like.Secondly, we discussed the relationship between the melt flow index and average molecule weight. We researched the behavior of the melt flow index on line and developed a model for prediction of the transient and the time mean values of MFR. The model is solved by the improved Gauss-Newton algorithm. The results were tested by the measured data and satisfactory agreement is obtained.Finally, we set up a series of sub-models according to the critical factors limiting the manufactures in auxiliary system respectively and carried out computation. We investigated the productive abilities of every part of the system at present. The corresponding results we obtained will give valuable references to the further technology improvement.