Process Heat Integration between Distillation Columns for Ethylene Hydration Process

Abstract

Distillation is a separation technique widely used in the chemical industry and highly energy consuming. The trends of energy price are rising continuously due to the limitation of energy supply and the increase of its demands. There are many ways to improve energy efficiency. Columns targeting is one of them by applying pinch technology for improving distillation columns of the existing process to reduce the energy consumption and the operating cost. By column targeting, columns can be modified by changing reflux ratio, preheating feed, or adding side reboilers and/or side condensers. The use of Column Grand Composite Curve (CGCC) shows the scope of each modification. The results from column targeting can be integrated with the background process by heat exchanger network (HEN) using mathematical programming to help reduce energy usage. The case study of the ethanol production by ethylene hydration is simulated for this study, containing three distillation columns. Process heat integration by using graphical method of column targeting and mathematical programming is applied. The HEN design with maximum net present value (NPV) is selected as the best design.