Condensers optimum water flow rate

The design conditions set the values of q and and the heat capacity of water may ordinarily be approximated as 1 Btu/(lbX°F). Therefore, Eq. (52) shows that the flow rate of the cooling water is fixed if the temperature of the water leaving the condenser (t2) is fixed. Under these conditions, the optimum flow rate of cooling water can be found directly from the optimum value of t2-The annual cost for cooling water is wHyCw. From Eq. (52),... 

Optimum flow rate of cooling water in condenser, 368-371... 

We desire to use a distillation column to separate an ethanol-water mixture. The column has a total condenser, a partial reboiler, and a saturated liquid reflux. The feed is a saturated liquid of composition 0.10 mole fraction ethanol and a flow rate of 250 mol/hr. A bottoms mole fraction of 0.005 and a distillate mole fraction of 0.75 ethanol is desired. The external reflux ratio is 2.0. Assuming constant molar overflow, find the flowrates, the number of equilibrium stages, optimum feed plate location, and the liquid and vapor compositions leaving the fourth stage from the top of the column. Pressure is 1 atm. 

With oxygen present a much lower selectivity was attained in acetic acid/CCAld condensations than with either water present or with no additive. Although CCA production was greater, this did not enhance the production of ketones. It was impossible to say whether the inhibition resulted from more total oxidation or from deactivation of active sites for condensation. Flint et al. found that the yield to 4-heptanone from butanol was maximized at a butanol/oxygen ratio of 6/1, using a 40% Ce02/MgO catalyst, at one particular flow rate. At other flow rates the optimum ratio varied from 3/1 to 1/1. They also found that butanol conversion was positive order with respect to oxygen. But they con-... 

D20. A distillation column with a total condenser and a partial reboiler is separating ethanol and water at 1 kg cm pressure. Feed is 0.32 mole fraction ethanol and is at 30° C. Feed flow rate is 100 kmol/h. The distillate product is a saturated liquid, and the distillate is 80 mol% ethanol. The condenser removes 2,065,113 kcal/h. The bottoms is 0.04 mole fraction ethanol. Assume that CMO is valid. Find the number of stages and the optimum feed stage location. 

The feed flow rate is 2000 kmol/day. Feed is 48 mol% methanol and 52 mol% water and is a subcooled liquid. For every 4 moles of feed, 1 mole of vapor must condense inside the column. Distillate conposition is 92 mol% methanol. Reflux is a saturated liquid, and Lq/D = 1.0. Bottoms conposition is 8 mol% methanol. Boilup ratio is V/B = 0.5. Equilibrium data are given in Table 2-7. Assume that CMO is valid. Find the optimum feed plate location and the total number of equilibrium stages required. 

El. A system known as a punp-around is shown below. Saturated liquid is withdrawn from stage 2 above the partial reboiler, and the liquid is returned to stage 3 (assume it is still a saturated liquid). Pump-around rate is P = 40.0 kmol/h. The column is separating methanol and water at 101.3 kPa. The feed flow rate is 100.0 kmol/h. The feed is 60.0 mol% methanol and 40.0 mol% water. The feed is saturated liquid. We desire a bottoms product that is 2.5 mol% methanol. The distillate product should be 95.0 mol% methanol. The column has a total condenser and the reflux is a saturated liquid. Assume CMO. Use (L/D) = 2.0 x (L/D)Tnin- Data are given in Table 2-7. Find Xp, the optimum feed stage and total number of equilibrium stages required. 

E3. A distillation column with at total condenser and a total reboiler is separating ethanol from water. Reflux is returned as a saturated liquid, and boilup is returned as a saturated vapor. CMO can be assumed. Assume that the stages are equilibrium stages. Column pressure is 1 atm. A saturated liquid feed that is 32 mol% ethanol is fed to the column at 1000 kmol/h. The feed is to be input on the optimum feed stage. We desire a distillate conposition of 80 mol% ethanol and a bottoms conposition that is 2 mol% ethanol. A liquid side stream is removed on the eighth stage from the top of the column at a flow rate of S = 457.3 kmol/h. This liquid is sent to an intermediate reboiler and vaporized to a saturated vapor, which is returned to the column at its optimum feed location. The external reflux ratio is Lq/D = 1.86. Find the optimum feed locations of the feed and... 

---