This research is designed to optimize energy consumption based on exergy analysis of distillation unit # 2 of Isfahan Oil Refinery. Based on this goal, the process unit was initially simulated by Aspen Plus software, and the gained results was validated by daily data. Then, based on exergy analysis, equipment with highest exergy loss and lowest exergy efficiency were identified. Results of exergy analysis indicate that atmospheric and vacuum distillation towers have highest exergy loss and by considering various operating characteristics of the processing unit, there is high potential for optimization of the unit. In the next step, in order to identify most effective operational characteristics on exergy loss and efficiency, sensitivity analysis was performed on the towers. Finally, optimization of the unit was performed by application of the jellyfish search algorithm on two objective functions of energy consumption and exergy loss. In order to validate the optimization results of the jellyfish search algorithm and eva‎luate its operation, optimization was also done by the differential evolution algorithm and results of the both algorithms were compared. The optimization results using the jellyfish search algorithm by the objective function of energy consumption indicated that amounts of energy consumptions can be reduced by 3.53% for fuel, 4.43% for steam and 5.07% for electricity, which these results lead to annual cost reduction of 942 thousand US dollars, i.e., 268.5 billion Rials. These values are by using the differential evolution algorithm for the objective function of energy consumption are 2.4% for fuel, 3% for steam and 3.1% for electricity which are equivalent to annual cost reduction of 642 thousand US dollars. The optimization results using the jellyfish search algorithm based on objective function of exergy loss indicated that the amounts of energy consumptions can be reduced by 3.31% for fuel, 3.71% for steam and 3.4% for electricity. These values lead to annual cost reduction of 880 thousand US dollars, equal to 250 billion Rials an. These values based on application of differential evolution algorithm for exergy loss objective function are 1.95% for fuel, 2.54% for steam and consumption of 2.55% for electricity which results in annual cost reduction of 518 thousand dollars. Finally, to compare the performance of these two algorithms, it was found that the JSA algorithm has a better performance for the both objective functions of exergy loss and energy consumption.

محسن محمدي , مسعود بهشتي

محسن محمدي , محمدرضا احساني