申論題

3. It is desired to produce 1000 kg/h of Na₃PCO₄ • I2H₂O crystals from a feed solution containing 5.6 wt% Na₃PO₄ and traces of impurity. The original solution is first evaporated in an evapprator to a 35 wt% Na₃PO₄ solution and then cooled to 293 K in a crystallizer, where the hydrated crystals and a mother liquor solution are removed. One out of every 10 kg of mother liquor is discarded to waste to get rid of the impurities, and the remaining mother liquor is recycled to the evaporator. The solubility of Na₃PO₄ at 293 K is 9.91 wt%. Calculate the kg/h of feed solution and kg/h of water evaporated. (25%)