Column with External Decanter and Recycle

Assuming that the composition of the top vapor stream reaches the ternary azeotrope (with the minimum temperature of the whole system), the compositions of both the AO and the OR can be estimated. With the known fresh-feed flowrate and the lever rule, the flowrate of the OR and the makeup flowrate can be estimated by the inner and outer material balance envelopes, respectively. Second, from the tie-line information and the lever rule, the flowrate of the AO stream can also be estimated. Thirdly, by using the outer material balance envelop and the lever mle, the bottom flowrate can further be estimated. Finally by using the inner material balance envelop and the lever mle, the top vapor flowrate can be estimated. 

With a converged flowsheet simulation mn, the design specJvary function in RadFrac can be used to set the purity of the bottoms product stream. Note that, because there is only one operating specification for the stripper, only one design spec jvary can be used. 

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