Optimisation of commercial production processes for polyester resins

Abstract

This thesis describes the work undertaken for the Teaching Company organised between BIP Chemicals Ltd and the University of Aston, Department of Chemical Engineering and Applied Chemistry. The overall aim of the scheme was to examine the process parameters involved in commercial polyester production and recommend new procedures to ensure both consistent process operations and product quality. The specific reactions involved in the preparation of polyester resins are discussed along with commercial manufacturing methods. The traditional quality control testing methods are described in order to compare with the techniques developed in the Teaching Company, i.e new control tests to determine the solids and ash content of polyesters. The result has been a significant reduction in test time and improved reproducibility of measurement. Therefore, hold-ups associated with awaiting results are reduced, thus increasing plant availability, resulting in a potential increase in production equivalent to £652,548 pa additional contribution. The data are recorded to a higher degree of accuracy than is achievable by the standard test method, providing a firm basis on which to measure improved product quality. The installation of a mass flow meter into the distillate line of one reactor has provided an additional control parameter, i.e the water removed from reaction can be measured, thus providing a better understanding of the course of the reaction and control of the overhead equipment. Optimisation of existing equipment, such as an ultrasonic homogeniser and the cooling water flow rates to the overhead equipment, have further improved productivity by 37% on one of the smaller reactors.The research work has been highly successful, with new control strategies and new test methods improving productivity and hence providing the potential for large financial returns.