Problem 1 (35 points). A liquid stream consisting of 7.0 mole\% n-butane and the balance a heavy nonvolatile hydrocarbon is fed to the top of a stripping column, where it is contacted with an upwardflowing stream of nitrogen. The residual liquid leaves the bottom of the column containing all of the heavy hydrocarbon, 5.0% of the butane entering the column, and a negligible amount of dissolved nitrogen. Part a) (15 points) Draw and completely label a process flow diagram representing this system. Part b) (15 points) The highest possible butane mole fraction in the exiting gas is that in equilibrium with the butane in the entering liquid (a condition that would require an infinitely tall column to achieve). Using Raoult's law to relate the mole fractions of butane in the entering liquid and exiting gas, calculate the molar feed-stream ratio (mol gas fed/mol liquid fed) corresponding to this limiting condition. Part c (5 points) Suppose the actual mole fraction of butane in the exit gas is 85.0% of its theoretical maximum value and the percentage stripped ( 95.0% ) is the same as in the first part of the problem. Calculate the ratio (mol gas fed/ /mol liquid fed) for this case