Estimate the pressure drop in the column of Examples 21.4 and 21.5 if the weir height is 4 in.

Examples 21.5

Estimate the efficiency of the distillation column in Example 21.4. The feed viscosity is 0.25 cP. Then calculate the number of actual trays in the column and the column height.

Example 21.4

A distillation column that has a total condenser and a partial reboiler is fed 500 kmol/h of an equimolar mixture of pentane and hexane. The feed is saturated liquid. It is necessary to produce outlet streams containing 95 mol% pentane and 99 mol% hexane. The distillation column contains a partial reboiler and a total condenser and operates at 1.4 times the minimum reflux ratio, which is a reflux ratio of 1.06. It has been determined that the column requires 15 equilibrium stages with the feed on Stage 5. The pressure at the bottom of the column is 2 bar. Assume that the McCabe-Thiele approximation is valid.

1. Determine the exit flowrates, D and B.

2. Determine all of the internal flowrates.

3. Determine the required column diameter for sieve trays with a 24-

in tray spacing operating at 75% of flooding with 88% active area.

Transcribed Image Text:

Data provided: Pentane Hexane A Antoine Coefficients 6.85296 6.87601 B 1064.84 1171.17 с 232.012 224.408 SG 0.626 0.655