Staged stripping of light alkanes. a supply of heavy (non-volatile) crude oil from a particular reserve contains a propane mole fraction of 0.04, which is stripped by contacting the crude with pure super-heated steam in a trayed stripping tower. the final mole fraction of propane in the crude must be ≤ 0.002. the temperature is held constant at 500 k, and the total pressure is 3 atm. the vapor flow rate of steam is 10.5 kg-mol min-1 while the liquid flow rate for the crude oil-propane mixture is 315 kg-mol min-1 . the vapor-liquid equilibria for propane in steam, compared to within crude oil, is given by y(propane) =25*x(propane). in this case, steam is an inert gas and will not condense.

a.) plot the operating and equilibrium line on a single graph. do not assume that ln = ln+1 or that vn = vn+1 for this problem (i. e., you need to exactly relate yn to xn+1 using the mass balance for ~ 6 points between x1 and xn+1).

b.) compare your answer from part a. to the operating line you would have found if you had assumed the system was dilute. would that be a good assumption in this case?

c.) using your plot, determine the number of equilibrium stages (i. e., the number of trays) needed for this separation.

d.) use the analytical kremser equation with the value of agm to calculate the number of stages needed.