One thousand kilograms per hour of a mixture containing equal parts by mass of methanol and water is distilled. Product streams leave the top and the bottom of the distillation column. The flow rate of the bottom stream is measured and found to be 673 kg/h, and the overhead stream is analyzed and found to contain 96.0 wt % methanol. a) Draw and label a flowchart of the process and the degree-of-freedom analysis.
b) Calculate the mass and mole fractions of methanol and the molar flow rates of methanol and water in the bottom product stream.
c) Suppose the bottom product stream is analyzed and the mole fraction of methanol is found to be significantly higher than the value calculated in part b). List as many possible reasons for the discrepancy as you can think of. Include in your list possible violations of assumptions made in part b).