Energy, economic and environment assessment of membrane-cryogenic hybrid recovery propane process — Process simulation and life cycle assessment

Abstract

Prevention and control of volatile organic compounds (VOCs) is one of the principal directions of air pollution control. Propane is not only a typical gas of VOCs but also a high value product. In this work, membrane-cryogenic hybrid processes to recover propane from nitrogen were studied by process simulation. Meanwhile, life cycle assessment methods were also used to assess the environmental impact of the entire life cycle process. Performance evaluation of the hybrid process was quantified in three aspects: energy, economic, and environment. The evaluation results indicated that it has more environmental and economic benefits to recover propane from 1.0 to 5.0% C3H8/N2. The energy consumption and recovery cost could decrease significantly. The lowest propane recovery costs are 984 USD/ton (1.0% C3H8/N2) and 234 USD/ton (5.0% C3H8/N2), respectively. At the same time, the environmental impact (excepted water resources consumption) generated by the hybrid process is substantially lower than by the cryogenic process. Pollutants output of hybrid processes is less than one-third of the cryogenic process. Climate change (GWP) can reduce from 2.37 × 104 kg CO2 eq to 4.54 × 103 kg CO2 eq to recover 1 ton propane from 1.0% C3H8/N2. Compared to propane processes produced from natural gas or liquefied petroleum gas, the environmental impacts caused by the hybrid processes are not much more than. In general, the membrane-cryogenic hybrid process is a green and economical technology to recover propane.