Page 106 - Separation process engineering

D2.* Two flash distillation chambers are hooked together as shown in the diagram. Both are at 1 atm
pressure. The feed to the first drum is a binary mixture of methanol and water that is 55 mol%
methanol. Feed flow rate is 10,000 kmol/h. The second flash drum operates with (V/F) = 0.7 and
2
the liquid product composition is 25 mol% methanol. Equilibrium data are given in Table 2-7.
a. What is the fraction vaporized in the first flash drum?

b. What are y , y , x , T , and T ?
2
1
1
1
2

D3. We are separating a mixture of methanol and water in a flash drum at 1.0 atm pressure. Use the
equilibrium data listed in Table 2-7. Feed rate is 10.0 kmol/h.

a. The feed is 40 mol% methanol and 60% of the feed is vaporized. Find mole fractions and flow
rates of vapor and liquid products. Estimate the temperatures by linear interpolation for both
vapor and liquid products.

b. The feed is 40 mol% methanol, the product temperatures are both 78.0°C. Find the mole
fractions of liquid and vapor products and V/F.
c. We desire a vapor product that is 80 mol% methanol and want to operate at V/F = 0.3. What
must the feed composition be?

D4. We have a mixture that is 20 mol% propane, 35 mol% n-butane, and 45 mol% n-hexane. If a flash