Question

Feed saline (salt) water containing 5 wt% dissolved solids and the balance water enters an evaporator plant. The purpose of the evaporator plant is to concentrate the saline solution and to reduce its volume before discharge to a nearby waste storage dam. The feed saline water entering the evaporator unit is concentrated by a factor of 5 (wt% basis). The throughput of the evaporator is limited to 150 kg/h. When the feed saline water flowrate exceeds 150 kg/h, the excess feed water (flow above 150 kg/h) is bypassed around the evaporator and mixed with the concentrated saline water. The combined stream is then discharged to the storage dam. If the flowrate of the feed brine solution entering the plant is 200 kg/h, determine:

a) the flowrate of the concentrated brine water (evaporated plus bypassed) going to the waste storage dam

b) the composition of this concentrated brine water. Show the full systematic mass balance approach.

Answer 1