. This system works as water and benzene are high immiscible and the partition coefficient (K’ _D ) for dioxane from the water to the benzene phase is about 1.3.

You work for a smaller chemical manufacturer that is thinking about getting into the dioxane business. The pilot scale reactor that they are designing will produce a 30 wt% dioxane in water solution at the rate of 2000 kg/hr. They want to recover 98% of the dioxane using a fresh benzene feed. Because of storage capacity and environmental permit limitations, they are limited to a benzene flow rate of no more than 5000 kg/hr. How many cross-current stages are needed to meet the required recovery rate with the benzene flow rate limitation (assume an equal flow rate to each stage)? How many countercurrent stages are needed accomplish the same recovery rate with the same benzene flow rate limitation? When comparing the number of stages needed for the two cascade systems, are the relative values what you would expect? Why or why not?