Data for the equilibrium of water and n-butanol at 1.0 atmosphere are given in Table 8-5. Plot y_w vs. x_w. A feed of 100.0 kmol/h that is 20.0 mol% water is fed to flash chamber A, which is the first of two flash chambers. The vapor from flash chamber A is 40.0 mol% water. This vapor is then partially condensed and fed to flash chamber B. In flash chamber B, 40.0% of the vapor from chamber A is condensed.

a. What are the flow rates Lwater,A and VA, and what is the value of Xwater,A?

b. What are the flow rates LB and VB, and what are the values of Xwater, B and Ywater,B?

c. Suppose we changed the operation of chamber B so that enough vapor was condensed to give a liquid mole fraction of X_{water, B} = 0.200 mole fraction water. If X_{water, B} = 0.200, what are Y_water,B, L_B, and V_B? We could now recycle liquid L_B to the feed (also 20.0% water) and produce only V_B,new and L_A, new as products. Calculate the new flow rates when L_B with water mole fraction 0.200 is recycled.

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D4. A mixture of methanol and water is sent to a flash distillation drum operating at 1.0 atm. Feed rate is 10.0 kmol/h. The feed before the valve in Figure 2-1 is at 102.0C and a pressure of 5.0 bar. Equilibrium data are in Table 2-8. a. Feed is 40.0 mol% methanol and V/F = 0.60. Find V, L, y, x, Tdrum. b. Feed is 40.0 mol% methanol and T = 78.0C. Find y, x, V, and L. c. V/F = 0.300. Vapor product is 80.0 mol % methanol. Find x, V, L, and z. d. If the drum is adiabatic, how would you determine Q for the flash drum for these three problems?