Due to the increasing in the greenhouse gas emissions, the world is shifting towards the green fuels. In this regard, natural gas and natural gas liquids (NGLs) are considered to be the attractive options. In this study, the simulation of the NGLs fractionation process was performed using Aspen HYSYS. The single and multi-objective optimizations were done based on the Genetic Algorithm method. The energy consumption, recovery of propane and butane, and economic analysis were selected as the objective functions for optimisation studies. Also, the feed temperature, feed molar flow rate, and the trays number of the column are design variables. Based on the consideration of the multi-objective optimisation (Maximum Profit-Minimum power), with increasing the profit, the power increases. Also, a cluster data for the temperature of feed gas can be seen at about 68.2 °C. With increasing the feed molar flow rate, the profit and power increases. Two other cases of the multi-objective optimizations were done: Minimum Power-Maximum Recovery and the Maximum Profit-Maximum Recovery. The optimum conditions of the process were found in these optimizations studies. Also, the results showed that the simultaneous optimisation of three objective functions should be accounted for a comprehensive optimisation of the process.
OmidbakhshAmiri et al. (2025) studied this question.