Glauber's salt, na2so4.10h2o, is to be produced in a swenson-walker crystalliser by cooling from 300 k to 290 k a solution of anhydrous na2s04 which saturates at 290 k. cooling water enters and leaves the unit at 280 k and 285 k respectively and evaporation effect is negligible. the concentration of salt in the feed is 0.40 kg/kg water and the solubility of anhydrous na2s04 in water is 14 kg/100 kg water at 290 k, the mean heat capacity of the liquor is 3.8 kj/kg k and the heat of crystallisation is 57.5 kw. for the crystalliser, the available heat transfer area is 3 m2/m length, the overall coefficient of heat transfer is 0.15 kw/m2 k. take 1 kg of feed solution as the basis and the flow as countercurrent. i) determine the length of the crystallizer required to process 0.25 kg/s of the product ii) if a concurrent flow system is used with the same temperatures conditions for the cooling water, what would be the length of the crystalliser? iii) which flow system would you recommend and give a reason