Question: an evaporationcrystallization process is used to recover solid potassium sulfate...
An evaporation-crystallization process is used to recover solid potassium sulfate (K2SO4) from an aqueous solution. The fresh feed contains 20 wt% K2SO4. A wet filter cake is produced in the crystallizer-filter that contains two phases: a solid K2SO4 crystal phase and a 40 wt% K2SO4 liquid solution. The ratio of solid crystals to solution is 10 kg crystals/kg solution. The filtrate, which also contains 40 wt% K2SO4, is mixed with the fresh feed and recycled to the evaporator. The evaporator removes 45% of the water fed to the evaporator at a flow rate of 175 kg/s. Calculate: a) The overall recovery of solid K2SO4 (%) b) The recycle ratio (recycle flow rate to fresh feed) c) The composition of the stream leaving the evaporator.
CORRECT ANSWERS ARE: a) 96.2% b) 1.59 c) 46.42 wt% K2SO4 and 53.58 wt% water