Question

2500 lbm/h of fresh fruit juice containing 88 wt% water and 12 wt% solids is sent to an evaporator. 75% of the water (by mass) is removed in the evaporator, producing a concentrated product. Determine the amount of water evaporated (in kg/s) and the concentration of solids (in wt%) in the product stream. Draw a flow chart.

Answer 1

Flow chart

Feed entering = 2500 lb/hr it contains 88% water, so water= 2500*88/100=2200 lb/hr solids =2500-2200= 300 lb/hr

Water evaporated= 75% of the water= 2200*75/100= 1650 lb/hr =1650*0.4535/(60*60) kg/s ( 1lb=0.4535 kg) =0.2078 kg/sec

Outlet contains water= 2200-1650 lb/hr and juice= 300 lb/hr

At the outlet : water =550 lb/hr and juice =300 lb/hr

composition : water =100*(550/550+300)= 64.7% and water =100-64.7= 35.3%