Application of multi-objective evaluation based on decision variables in teaching:Extractive distillation separation of isobutene/isobutane
[Objective]Taking the separation of isobutene/isobutane by conventional and side-stream extractive distillation as the research object,the optimization design of conventional and side-stream extractive distillation was conducted based on decision variables.[Methods]A multi-objective evaluation was conducted from the perspectives of energy,economy,thermodynamics,and environment.The optimal operating parameters for the conventional and side-stream extractive distillation and solvent recovery columns were obtained through the optimization of decision variables.Two extractive distillation processes were optimized with TAC as the target,and the optimal feed stage,extractant feed stage,and number of theoretical and sideline extraction stages were obtained.[Results]The TAC of the optimized conventional and side-stream extractive distillation was 3.26 × 106 and 3.1 × 106 $/year,their TEC was 14 041.9 and 13717.87 kW,and their CO2 emissions were 4 831 and 4 714kg/h,respectively.Compared with those of the conventional extractive distillation process,the CO2 emissions,TAC,and TEC of the side-stream extractive distillation were reduced by 2.4％,5.2％,and 2.4％,respectively.The thermodynamic efficiency increased from 22.4％of the conventional extractive distillation to 23.2％of the side-stream extractive distillation.These results show that,in terms of economic and environmental benefits,the side-stream extractive distillation had greater advantages than the conventional extractive distillation.With two extractive distillation design schemes,students'innovative thinking is stimulated,and new distillation technologies and methods are explored.[Conclusions]Through multi-objective evaluation methods,students'practical ability in distillation operations and awareness of energy saving and consumption reduction are cultivated,enhancing their awareness of energy efficiency and sustainable development concepts,which is conducive to improving their enthusiasm for learning and strengthening their innovative ability in engineering practice.
extractive distillationdecision variablesmulti-objective evaluationengineering practice
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