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Abstract: Multi-component separation by distillation is known as a conventional method in chemical processes. In this study the effects of feed splitting on three classical arrangements (with and without heat integration) were investigated in order to reduce the total annual cost (TAC). Ternery mixture separation (propane, butane and pentane) by distillation was selected as a case study. An optimization problem was defined based on the effective parameters affecting the total annual cost. Optimum values for decision variables were calculated by applying the genetic algorithm. Calculation results showed that the heat integration procedure in the feed splitting method reduced the TAC significantly. It was also indicated that the prefractionator arrangement with heat integration resulted in the greatest decrease in the total annual cost. [Copyright &y& Elsevier]

• 93 different processes in the ETBE production have been optimized and compared. • In the pervaporation process, series-parallel arrangement along with recycle streams is used. • Combination of HIDiC, FS, and HI methods was used to reduce the energy consumption. • All process parameters are considered as the optimization variables. A new process configuration consisting of hybrid pervaporation (PV) (with series–parallel arrangement and recycle streams)–distillation column (DC) or reactive distillation (RD) with a hybrid feed splitting-heat integrated distillation column (HIDiC) – heat integration method was proposed to produce ETBE. To evaluate the performance of the proposed method, 92 different processes for producing ETBE by RD columns, pressure swing distillation, PV, liquid–liquid extraction column or their combinations were optimized and compared to the new configuration. The PV modules were placed in four sections: before the column, next to distillate, next to bottom product and next to side stream. All process parameters in DC or RD, PV and heat integration were considered optimization variables, and all variables were simultaneously optimized by a hybrid GA–PSO algorithm. The proposed configuration reduced TAC by at least 30% and a maximum of 62% compared with other process configurations. This can be attributed to the use of PV instead of distillation columns, series–parallel arrangement instead of series and parallel arrangements in the PV process to reduce energy consumption and membrane area and also the use of heat integration between internal DC flows and PV streams to eliminate the need for hot utility. [ABSTRACT FROM AUTHOR]

• Rather than PSD and ED methods, PV was used in methanol recovery section in the TAME process. • For the first time,combination of HIDiC, feed splitting, and heat integration was used to save energy. • The heat integration between internal streams of RD column and retentate streams of PV was investigated. • All process parameters (especially PV parameters) were considered as optimization parameters. This study combines feed splitting, internal heat integration, and heat integration between Pervaporation (PV) retentate streams and internal streams of reactive distillation (RD) column employed in TAME production in an attempt to optimize energy consumption in the process. All process parameters in the RD column, PV membrane process, and process energy consumption were optimized simultaneously. Further, the possibility of heat exchange between hot and cold streams was investigated by the optimization algorithm in internal heat integration in the RD column (R-HIDiC) as well as heat integration between retentate streams in PV modules and internal streams in the RD column. Accordingly, the number of heat exchangers and the heat exchange ratio of the streams was determined by the optimization algorithm. The Total Annual Cost (TAC) was adopted as the objective function to be optimized by a combination of Genetic Algorithm (GA) and Particle Swarm Optimization (PSO) algorithm. Twelve different processes were optimized and compared. Optimization results suggest that the hybrid R-HIDiC–PV process with feed splitting and heat integration reduced the energy consumption by 42 % and TAC by 45 % compared to the hybrid PV–RD process and by 47 % and 48 %, respectively, compared to the hybrid RD–Pressure swing distillation process. [ABSTRACT FROM AUTHOR]

• Rather than PSD and ED methods, PV was used in methanol recovery section in the TAME process. • Heat integration was conducted by combining R-HIDiC and PV. • All process parameters (especially PV parameters) were considered as optimization parameters. • Heat transfer fraction and number of heat exchangers in R-HIDiC were obtained by the optimization algorithm. The TAME production process involves two main steps. The first step pertains to the reactions that lead to the synthesis of TAME, and the second step to the separation of TAME and recovery of methanol. Part of the TAME reaction and separation is carried out in a reactive distillation (RD) column. The product at the top of the RD column is a methanol- and C 5 -containing azeotropic mixture which can be isolated through pressure swing distillation (PSD) and extractive distillation (ED) methods. In this paper, the mixture was isolated through the pervaporation (PV) process, and all parameters related to RD and PV were considered as optimization variables, in particular the PV-related parameters such as the permeate stream pressure, the number of modules, and the temperature of inflow to each module. All variables were optimized simultaneously. The GA and PSO algorithms were combined to optimize the process and, additionally, total annual cost (TAC) was used as the objective function. The internally heat integrated distillation column (HIDiC) method was used to reduce the RD column energy costs, and the number of heat exchangers between the two rectifying and stripping sections was obtained using the optimization algorithm. The results showed that the hybrid PV/R-HIDiC process with heat integration was the best arrangement, resulting in a TAC reduction of 30% and 40% compared to the hybrid PV/RD process and the hybrid PSD/RD process, respectively. In this case, the number of trays in rectifying and stripping sections is respectively 22 and 6. The number of heat exchangers obtained by R-HIDiC method is 5, the number of PV modules is 11 and permeate pressure equals 18 as the most important parameters obtained from the optimization algorithm. [ABSTRACT FROM AUTHOR]

A new structured packing with the specific surface area of 2100 m 2 m −3 (PACK-2100) was characterized through experimental and numerical studies to evaluate its performance in the distillation column. For serving this purpose, various operational conditions were studied to assess the main parameters such as wet pressure drop and liquid holdup of PACK-2100. The results indicate that the wet pressure drop and hold up values are enhanced in comparison to commercial ones. In addition, the pressure drop slowly increases from 0.5 to 25 millibar per meter of packing as mass flow rates of air and liquid flow are increased. In the similar manner, the holdup is raised from 12% to 33%. The numerical simulations were also performed to describe the flow pattern inside of the PACK-2100. The computational results confirmed that the liquid stream fall on the surface of packing forming the uniform film. The present study introduces the new packing of PACK-2100 with superior characteristics for special application in the systems with a low separation factor. [ABSTRACT FROM AUTHOR]