Applications of pinch technology (heat exchanger network design and process heat integration)

Abstract

Gas separation process is one of the cryogenic processes. The operating expenditures for this process are dominated by the refrigerant cost. To reduce the cost, the energy saving is needed. Pinch technology is one of the energy saving techniques. This technique provides the opportunities for energy saving by process modifications. In this research, two applications of pinch technology, distillation column targeting and heat exchanger network modifications, were applied to PTT gas separation plant unit I. The commercial simulation software; Aspen Plus and Aspen Pinch, were employed in this work. The result for distillation column targeting showed that all distillation columns; demethanizer, deethanizer, and depropanizer, were optimized at the design conditions. In the design case study of heat exchanger network modifications, the value of minimum temperature difference (∆Tmin) should be selected appropriately. In this work, the value of 2 K was used. The results showed that the energy requirements were reduced from 12.18 to 7.80 MW for cold utilities, which corresponds to US$ 71,018.60/yr of operating cost saving. Finally, thermodynamic efficiency of the process was improved from 14.01 to 15.91 %