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Unformatted text preview: ontinued) Exercise 7.41 (continued) (b) From Eq. (742), Eo = 13.3  66.7 log Take the viscosity as that of the feed = 0.34 cP Eo = 13.3  66.7 log (0.34) = 44.6% This is poor agreement with the performance data. (c) From Eq. (743), Eo = 50.3()0.226 At the feed composition, x = 0.36 and y = 0.71. Therefore, from Eqs (219) and (221 combined, the relative volatility is, = ( y/x)/[(1  y)/(1  x)] = (0.71/0.36)/(0.29/0.64) = 4.4 Exercise 7.41 (continued)
Analysis:
Eo = 50.3[(4.4)(0.34)]0.226 = 45.9% Now correct for length of liquid path from Fig. 7.5. Column diameter = 6 ft. Assume length of liquid path = 70% of column diameter = 0.7(6) = 4.2 ft. From Fig. 7.5, correction to be added = 10%. Therefore corrected Eo = 45.9 + 10 = 55.9% This also appears to be low. (d) From Eq. (656), NOG =  ln (1  EOV). Therefore, EOV = 1  exp(NOG) Use Eqs. (662, (664), (666), and (667) as in Example 6.7. Carry out the calculations at the bottom tray based on methanol diffusion. Conditions are: Molar flow...
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 Spring '06
 selebi
 Distillation, pH, Mass Transfer

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