Acontinuous distillation column with reflux is to be designed to separate 30, 000 kg/h of a mixture of 40 wt% benzene and 60 wt% toluene into an overhead product containing 97 wt% benzene and a bottom product of 98 wt% toluene. a reflux ratio of 3.5 mol distillate to 1 mol of product is to be used. the molal latent heats of benzene and toluene are 7360 and 7960 cal/g mol, respectively. benzene and toluene form a nearly ideal solution with a relative volatility of about 2.5. the feed has a bubble point of 95 °c at a pressure of 1.0 atm.
(a) calculate the moles of overhead product and bottom product per hour.
(b) determine the number of ideal plates and the position of the feed plate
(i) if the feed is liquid at its boiling point;
(ii) if the feed is liquid at 20 °c (specific heat 0.44 cal/g. °c);
(iii) if the feed is a mixture of two-thirds vapor and one- third liquid.
(c) if steam at 1.36 atm gauge is used for heating, how much steam is required per hour for each of the above three cases, neglecting heat losses and assuming the reflux is a saturated liquid.
(d) if cooling water enters the condenser at 25 °c and leaves at 40 °c, how much cooling water is required, in cubic meters per hour? what is the cooling load of the condenser in kw?