Enhancement of single mixed refrigerant natural gas liquefaction process through process knowledge inspired optimization and modification

This study examined the enhancement of the single mixed refrigerant (SMR) natural gas liquefaction process. The effects of the main parameters, such as mixed refrigerant (MR) composition and operating pressures on the compression energy requirement were investigated. A process knowledge inspired decision-making method was exploited for liquefied natural gas process optimization. The results showed that the proposed optimization methodology is simple and effective in determining the optimal operating conditions and could save up to 30.6% in terms of the compressor duty compared to the base case. In addition, the proposed optimization methodology provides process understanding, which is essential to process engineers. Another benefit of the proposed methodology is that it can be applied to any MR liquefaction cycle. The use of heavier refrigerants, such as isobutane and isopentane, and the addition of a NG compressor were examined to improve the energy efficiency of the SMR process. The effect of the intercooler outlet temperature on energy saving was also considered. The synergistic effects of those modifications on improving the performance of the liquefaction process were investigated. (C) 2016 Elsevier Ltd. All rights reserved.