Development of Polymer Properties Prediction System for Operation of PE Reactor

Efficient operation of the polyethylene (PE) process is greatly dependent on the correct prediction or estimation of the properties including melt index, density and production rate. However, direct measurement of resin property has limitation due to cost of measuring equipment and long measurement period. Although product drops are made every few minutes to remove resin from a reactor, they vary in size and do not occur at a precisely known frequency. These problems make the difficulty of the real-time control of the product quality and lead to yield off-spec products, resulting in economic losses. For this reason, resin property in polyethylene process must be inferred or calculated from other process variables that are directly measured. The combination of online and offline measurement equipment information based on the process model not only improves the measurement performance of the quality variable but also contributes to the control performance of the product property. In this study, we developed some calculation methods based on material and energy balance around the reactor can be used to estimate the resin property in a PE process.