Applications of pinch technology for energy conservation

Abstract

The natural gas separation process is an extremely high energy-consuming process. It consists of distillation units and cryogenic heat exchangers requiring refrigerant. This leads to high operating costs. This study focuses on the gas separation unit I which has three main distillation columns: a demethanizer, deethananizer, and depropanizer. A simulation model of the columns was created using the Pro/II software program and the pinch technology technique to determine the excess energy by modifying the existing process to reach high energy savings. The pinch analysis was divided into two parts: distillation column targeting and heat exchanger networks (HENS). The simulation model gave equilibrium and thermodynamics data used for generating column grand composite curves (CGCCs) and column composite curve (CCCs). The demethanizer was modeled as four conventional columns connected in the series and a pinch point was found on CGCC which meant that this column was energy efficient. The depropanizer had one pinch point found in CGCC, while pinch point was not found in CGCC of the deethanizer. The background process was studied using six hot streams and seven cold streams to generate a composite curve for the process.