Question

A gas stream contains 40 mol% n-hexane in nitrogen (N2) and flows at 6600 L/min, 60◦C, and 1 atm from a soybean oil extraction process. You are to use a condenser to liquefy and recover nhexane to recycle back to the oil extraction process. The current process specifications call for the condenser to operate at 15◦C. A liquid condensate stream is produced that is in equilibrium with the exiting gas stream.

(a) (15) Perform a degree-of-freedom (DoF) analysis to demonstrate you have enough information to calculate all the unknowns labeled on the flowchart. (b) (15) Write a complete set of equations for determining the unknown variables. Identify what each equation represents, (e.g. balance on , etc.). Fill in all known values and necessary unit conversions but do no arithmetic. If vapor pressures are needed, just write p ∗ i (T) where i is the species and T is the temperature value or temperature variable you intend to use in the equation. Outline an efficient procedure for solving the equations by numbering the equations in the order you will solve them and circling the variables for which you will solve. No algebra or numerical calculations. (c) (10) Using flowchart variables and/or flowchart amounts, write an expression for the percent recovery of n-hexane as liquid condensate. Fill in all known values and necessary unit conversions but do no arithmetic.

Answer 1