3. problem) A continuous fractionation distillation column with a flow rate of 30,000 kg/h will be designed to separate a mixture containing 42% benzene and 58% toluene with 97% benzene in the top product and 98% toluene in the bottom product by weight. The recovery (reflux) rate is determined to be 2.8 per 1 mole of product. Benzene and toluene form an ideal system with a relative volatility of 1.8. The molar latent heat values for benzene and toluene are 7360 and 7960 cal/gmol, respectively. The molecular weights for benzene and toluene are 78 and 92 g/mol, respectively. The feed has a boiling point of 95C at 1 atm pressure.

a) Calculate the upper and lower product quantities in mol/hr.

b) Determine the ideal number of stages and the stage at which the feed is made for the following three different cases.

i) If the feed is liquid at boiling point

ii) Feed liquid at 20C (specific heat of 0.44 cal/gC),

iii) A mixture containing two-thirds liquid and one-third vapor in the feed

c) If steam with a gauge pressure of 20 lbf/in2 (1.36 atm) is used for heating, heat losses neglecting and assuming that the recovery (reflux) is a saturated fluid, the above How much steam is required per hour for each of the three cases?

d) If cooling water enters the condenser at 32C and leaves at 48C, how many cubic meters per hour is cooling water needed?