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Question 4 Potassium dichromate (K2Cr2O7) is to be recovered from 25 wt. % aqueous solution. The solution is joined by a recycle stream and fed to a crystallizer/centrifuge where enough water is removed so the solution is 85 wt% water. Exiting the crystallizer are the crystals with 10% of the solution, and the remaining solution which forms the recycle stream. The filter cake, which contains 85 wt.% crystals and the rest solution is fed to a dryer where it is contacted with dry air. The remaining water is evaporated, leaving pure potassium dichromate crystals. The air leaves the dryer with 0.08 mol fraction water. For a production rate of 1000 kg/h of potassium dichromate crystals, determine the: • water evaporated in the crystallizer/centrifuge • mass flow rate of the recycle stream • moles of air that flow through the dryer mg kg/hr na mol 0.08 mol H20/mol 0.92 mol air/mol 1000 kg solids/hr m, kg/hr 0.25 kg KD/kg 0.75 kg H,0/kg Drier m. kg/hr m2 kg/hr Crystallizer/ 0.85 kg solids/kg / Centrifuge 0.15 kg soln/kg 0.15 kg KD/kg Recycled solution 0.85 kg H20/kg mg kg/hr 0.15 kg KD/kg 0.85 kg H,0/kg n, mol air