Research On Numerical Simulation Of Industrial Polyester Reactor Based On MATLAB

In this paper,a mathematical model of the esterification system,pre-polycondensation system and final polycondensation system of a polyester production plant with an annual output of 500,000 tons is established.The numerical simulation is carried out using MATLAB,and the components of each reactor at the liquid phase outlet are obtained.Concentration and technical indicators are compared and analyzed with design values.This paper examines the influence trend of process conditions on the parameters at the liquid phase outlet of the first esterification reactor,the second pre-polycondensation reactor and the final polycondensation reactor,and gives the corresponding adjustment measures for the process conditions to improve the technical indicators.The esterification rate,degree of polymerization,concentration of BHET and concentration of PET at the liquid phase outlet of the first esterification reactor and the second esterification reactor,the relative errors of their simulated values and design values are within 5%and 3%,respectively.The volumes of the first esterification reactor and the second esterification reactor are about 146 m3 and 40 m3,respectively,and the time consumed during the start-up process is about 30 h and 7 h,respectively.For the first esterification reactor,if it is necessary to further improve the technical indicators at the liquid phase outlet,measures can be taken to increase the temperature,reduce the pressure,and appropriately reduce the EG/PTA molar ratio of the slurry.The relative error of the esterification rate,degree of polymerization and PET concentration at the liquid phase outlet of the first pre-polycondensation reactor and the second pre-polycondensation reactor are within 2%and 5%of the simulated value and the design value,respectively.The volumes of the first pre-polycondensation reactor and the second pre-polycondensation reactor are about 30 m3 and 93 m3,respectively,and the time consumed during the start-up process is about 5 h and 20 h,respectively.For the second pre-polycondensation reactor,if it is necessary to further improve the technical indicators at the liquid phase outlet,measures can be taken to reduce the pressure.The esterification rate,degree of polymerization,concentration of PET and mass fraction of DEG at the liquid phase outlet of the final polycondensation reactor are all within 1%of the relative error between their simulated and designed values.The final polycondensation reactor has a volume of about 78 m3 and a tube length of 15 m.For the final polycondensation reactor,if it is necessary to further improve the technical indicators at the liquid phase outlet,measures can be taken to lower the temperature,reduce the pressure,and reduce the residence time of the material.