The composition of the feed to a debutanizer is given below. Make a preliminary design for a column to recover 98% of the n-butane overhead and 95% of the isopentane from the column base. The column will operate at 14 bar and the feed will be at its boiling point. Use the shortcut meth- ods and follow the procedure set out below. Use the De Priester charts in Dadyburjor (1978) to determine the relative volatility if solving by hand. The liquid viscosity can be estimated using the data given in Appendix C (available in the online material at booksite.Elsevier.com/Towler). 

 Feed composition:

a. Investigate the effect of reflux ratio on the number of theoretical stages. 

b. Select the optimum reflux ratio. 

c. Determine the number of stages at this reflux ratio. 

d. Estimate the stage efficiency. 

e. Determine the number of real stages. 

f. Estimate the foed point. 

g. Estimate the column diameter.

kg/h propane 910 isobutane i-C4 180 n-butane n-C4 270 isopentane nomal pentanc i-Cs 70 n-Cs 90 nomal hexane n-C. 20