hello everyone.... I am doing the computer simulation for the heteroazeotropic distillation. i am supposed to use a decanter for liquid-liquid phase splitting and also made the ternary plot. almost all literatures i studied describes the significance of decanter in a monotonous way.... like the bottom product of the concentrator column and the aqueous outlet from the decanter fall in two different distillation regions which enable the separation. How do I get the insight or the theory or explanation what happens if I don’t use the decanter. Which of the streams fall in the same distillation region and hinder our distillation? (The top product of the concentrator column is the ternary azeotrope) I am waiting for positive response for you
Computer simulation has long been recognised as a useful tool in improved process operation and design studies. Commercial simulation packages now available for batch distillation studies typically assume constant tray efficiency. Here, on the basis of both practical work and computer simulation, the effects of tray efficiency variation with tray liquid composition on model accuracy and column performance are investigated. For the heterogeneous azeotropic distillation configuration, a column will be designed to act as both the pre-concentrator column and the recovery column in the process. The fresh feed together with the aqueous outlet stream from decanter is fed into this combined column with the bottom product of near pure water and the top product is fed into the heterogeneous azeotropic column. The bottom product of this heterogeneous azeotropic column is pure ethanol and the top vapor of this column will be close to the lowest boiling point of the ternary system (ternary azeotrope). This top vapor stream after condensation can naturally separate into two liquid phases with the organic phase containing entrainer which can be recycled back to this heterogeneous azeotropic column to aid the separation and the aqueous outlet stream is fed into the combined column as mentioned previously. The Total Annual Cost (TAC) will be used as the objective function to be minimized for the above two-column design. Possible alternative entrainers will be compared to obtain the optimized flowseet with the lowest TAC. Heteroextractive distillation is, as the name indicates, a hybrid process where heteroazeotropic and extractive distillation are combined in a single process. The process requires the addition of an entrainer that forms a heteroazeotrope with only one (preferably) of the original components and at the same time interacts with the original components and changes its relative volatility. Since the added entrainer is double-effective, the process becomes very attractive
thank you prem baboo....well.... i think i couldnt put it in the right way.... but my query is what happens when we dont use the decanter..... what makes the distillation impossible when i dont use it.... thank you.... hope to get some more and useful replies
Dear Shanti,
Please see the link, when we dont use decanter.
regards,
Prem baboo
https://books.google.co.in/books?id=7QbUAgAAQBAJ&pg=PA306&lpg=PA306&dq=dont+use+the+decanter.....+what+makes+the+distillation+impossible&source=bl&ots=ZM0HvPPyy1&sig=e2psaR3_Z8YiCxbOyZOWmwL9mZg&hl=en&sa=X&ved=0ahUKEwjuy9ybgvzKAhXBSI4KHb7-BnEQ6AEIMDAD
the use of decanter depends on your azeotropes properties. i give an example for you, please see my article Journal of the Taiwan Institute of Chemical Engineers 44 (2013)577–585. A you see, there are two possible azeotropes to be formed at overhead and the overhead is combination of thus two azeotropes. in order to guarantee phase splitting and also to obtain pure components, some additional water is added to purify the stream. if we do not use decanter, proper phase separation is not obtained and a mixture of two azeotropes are existed at overhead.
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