Optimization of Integrated Low-Temperature Gas Separation Processes Using SA Method and Different Refrigerants

In low-temperature processes, heat rej ected from separation columns is removed byrefrigeration systems to heat sinks (reboilers & pre-heaters), process streams, otherrefrigeration streams, or external utilities. the need for efficient utilization andrecovery of energy in sub-ambient gas separation processes is still challenging.performance and reliability of simulated annealing (sa) for simultaneous design andoptimization ofsuch systems has been investigated previously. in this work, the effec t ofdifferent refrigerants satisfy ing a set ofprocess cooling duties at different temperaturesis addressed. cost reduction can be realized by encompassing both effective screeningofheat-integrated separation columns and selecting the best refrigerants. a 29.7% costsavings has been shown through a case study. afterwards, a comprehensivethermodynamic analysis has been carried out on achieved solution s to verify theaccuracy of existing shortcut models and robustness ofoptimized structure. it has beenshown that exergy analysis using two different approaches (i.e. stream wise and unitoperation wise) are the same, which indicate the accuracy of the used models.moreover, we have indicated that both utility costs and exergy losses can be consideredas an objective fun ction when optimizing the designs.