Retrofit for a Gas Separation Plant by Pinch Technology

This study focuses on retrofit of the PTT gas separation plant applying pinch technology. The prime objective is to maximize the energy recovery of the process via several tools including Problem Table Algorithm (PTA), Grand Composite Curve (GCC), Grid Diagram, and Column Grand Composite Curve (CGCC). The entire process consists of three main parts, distillation columns, heat exchanger networks, and the refrigeration system. There are thirteen hot and six cold streams with fourteen heat exchangers. Existing network is an unpinch process with ΔTmin lower than the threshold ΔTmin of 21ºC and the minimum temperature approach (ΔTmin) is observed around 1.06ºC. The column grand composite curve (CGCC) of Deethanizer and Depropanizer reveal the scope of energy recovery via side reboiling and feed preheating. The maximum energy saving can be obtained approximately 13.32% by integrating with heat exchanger network of background process. This reduces the annual energy cost about 6125989.118 US$/yr. In order to achieve it, the capital investment is necessary but the annual cost saving will be enough to recover the cost in less than one year.