Flowsheets Flowrates, industrial

In distillation calculations, molar flowrates and compositions are usually employed. Let us assume that the fresh feed flowrate is lOOkmol/h, the feed temperature is 25°C, and the feed pressure is 1.3 atm. These are entered in the middle of the window. The feed composition is 50 mol% IPA and 50 mol% water to represent a typical waste stream from semiconductor industry. The composition can be entered in terms of mole or mass fractions, or it can be entered in terms of component molar or mass flowrates. In our example, we use the dropdown arrow to change to Mole-Frac and enter the appropriate values. Repeat the same procedure to enter the feed-stream data of the entrainer feed (FFl) as can be seen in the flowsheet given in Figure 3.1. 

The economic optimal process flowsheet was obtained by minimization of the total annual cost (TAG) with five design variables IPA distillate composition (XD2) in the recovery column, total number of stages for the heterogeneous azeotropic column and the recovery column (Ni and N2), and the two feed stages (Api and Apa). The product specification of IPA is set to be ultrapure (99.9999 mol%) to be used in the semi-conductor industry. The product specification of water is set to be 99.9 mol%. In each simulation run, the IPA product specification is achieved by varying the reboiler duty of the heterogeneous azeotropic column, and the water product specification is achieved by varying the reboiler duty of the recovery column. The entrainer makeup flowrate will be very small to balance the entrainer loss from the two bottom streams. 

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