Separation Process Principles- 2n - Seader & Henley - Solutions Manual

1 in the forward direction from 0 to 1 and 01in the

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Unformatted text preview: te a 10-stage extraction unit for the given conditions. The model converged in 12 iterations, with the results given below. The product compositions differ little from those computed for 1 stage. Also, the interstage flow rates are almost constant for stages 1 to 7. Thus, a significant separation is not possible for any number of stages. The reason for this is clear if a line on the above ternary diagram is drawn from the feed point [30 mol% (2) at 0 mol% (3)] to the solvent point [100 mol% (3)]. This line is almost collinear with a tie line. Regardless of the number of stages and the number of equilibrium stages, a significant separation of cyclopentane and cyclohexane can not be made. Exercise 10.43 Subject: Liquid-liquid extraction of acetic acid from water by ethyl acetate at 100oF Given: Feed of 6,660 lb/h of acetic acid and 23,600 lb/h of water. Solvent of 68,600 lb/h of ethyl acetate and 2,500 lb/h of water. Ccountercurrent-flow extractor. Assumptions: NRTL equation for activity coefficients using the following parameters: I Ethyl acetate Ethyl acetate Water Find: J Water Acetic acid Acetic acid BIJ 166.36 643.30 -302.63 BJI 1190.1 -702.57 -1.683 αIJ 0.2 0.2 0.2 Number of equilibrium stages to extract 99.5% of the acetic acid. Analysis: The Extract model of Chemcad was used starting with 2 equilibrium stages and increasing by one until 99.5% extraction was achieved. For each run, convergence was achieved in 12 to 13 iterations. The results were: No. of stages % Extraction of Acetic acid 2 90.59 3 96.68 4 98.80 5 99.56 6 99.86 The results show that 5 stages are needed, but 6 stages is safer. Detailed results for 6 stages are: Exercise 11.1 Subject: Azeotropes and approximate residue curve map for the system n-hexane methanol - methyl acetate at 1 atm Given:. Ternary system n-hexane - methanol - methyl acetate at 1 atm. Find: All binary and ternary azeotropes from suitable references. Approximate residue curve map showing distillation boundaries. Type of node for each azeotrope and pure component. Analysis: The following azeotrope data were obtained from the "Handbook of Chemistry and Physics" or the 6th edition of "Perry's Chemical Engineers' Handbook": At 1 atm, the molecular weights and boiling points of the three components are: Component Molecular weight Normal b. pt., oC n-Hexane 86.17 69.0 Methanol 32.04 64.7 Methyl acetate 74.08 57.0 Binary azeotropes (all minimum boiling): Mixture, A/B Boiling pt., oC n-Hexane/Methanol 50.6 n-Hexane/Methyl acetate 51.8 Methanol/Methyl acetate 53.5 Wt% A/B 39.3/60.7 19.0/81.0 Ternary azeotrope (minimum boiling): Mixture, A/B/C Boiling pt., oC Wt% A/B/C n-Hexane/Methanol/ Methyl acetate 47.4 48.6/14.6/36.8 Mol% A/B 49.0/51.0 35.8/64.2 35.2/64.8 Mol% A/B/C 37.2/30.1/32.7 An approximate residue curve map on a right triangular diagram, of the type developed in Fig. 11.7, is shown on the next page. From that diagram, which includes approximate distillation boundaries, the following types...
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This document was uploaded on 02/24/2014 for the course CBE 2124 at NYU Poly.

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