EXTRACTIVE DIVIDED WALL DISTILLATION COLUMN: DESIGN .1 AND OPTIMIZATION

Abstract

Distilkition is widely used as a separation technique but it consumes more energy. Therefore it's nccessary to find efficient design which will reduce energy consumption maintaining sime desired purity. Many attempts have been made in this direction. Petlyuk proposed a promising. thermally integrated design which is highly energy efficient. Further, divided wall CCthI11fl (DWC) was introduced in which fully thermally coupled Petlyuk column configuration was implemented in one single column by providing single vertical wall dividing column into two parts. Out of these two parts, one works as pre or post fractionator, and othcr as main column. Thermodynamically both Petlyuk column and DWC are equivalent. 1 )ividcd wall column (DWC) finds many applications in the field of separation of liquid iiikture, viz., separation of three or more component mixture, separation of azeotropic In Ntules. extractive distillation, reactive distillation, etc. Examples of extractive distillation 6.1 include separation of aromatic compounds, aqueous alcohol solutions, mixture of liv diocarbons, etc. Amount of energy consumed is the major operating cost factor; therefore optimal design is obtained in terms of minimum energy consumption without compromising with the product quality. Design variables such as reflux ratio operating parameter such as feed temperature extracting agent flow rate and its temperature have significant effect on optimal design. In the plesent study we designed and optimized extractive dividing wall distillation column for dehydration of hio-ethanol. We used RADFRAC model of ASPEN PLUS simulator and N ftl'l, as property method. in the study we found that for economical and efficient operation proper design of column is iniportant, proper operating parameters like reflux ratio, total number of stages, operating InessLire, are important similarly feed condition such as temperature and flow rate also important for economic and efficient operation. By selecting proper teed temperature of In \lure to be separated, we can get desired purity with minimum or optimum expenses in terms of rehoiler duty and condenser duty. As we have seen with increment in feed lemperature recovery of pure ethanol increases but beyond certain value recovery continues to increase but quality decreases continuously along with continuous increase in reboiler duty. lhercforc we have to select optimum point in which we recover maximum ethanol with nax i mU ni purity.