Heat Exchanger Network Synthesis on Gas Separation Plant No.2 (GSP2) in Thailand

Energy conservation is one of the most common concerns in gas separation plants. It plays a key role in energy and operating cost saving of their high-energy consuming processes. Although many research works on heat exchanger network (HEN) synthesis has been extensively studied for more than 40 years, most of them have limitations on computational time and feasibility due to their mathematical difficulties. Thus, they are impractical for large problems as industrial cases. In this work, a strategy for HEN synthesis was presented and applied to the industrial case of gas separation plant no.2 (GSP2) in Thailand consisting of twelve hot and eleven cold process streams. The strategy for HEN synthesis is a combination of Pinch Technology, the well-known thermodynamics-based approach, and mathematical programming based on the stage-wise superstructure model. HEN was synthesized in two parts; above and below pinch, corresponding to the optimal pinch temperature as well as the heat recovery approach temperature (HRAT) predicted by Pinch Analysis in order to assure near-optimal design. The HEN was then improved by a mathematical model applying relaxation technique based on a concept of loop and path toward better design with less complexity. According to the industrial case of GSP2, the proposed strategy for HEN synthesis is effective where a good solution can be obtained with reasonable computational time.