The triple effect evaporator, each effect of which has 1500 ft of the heating surface is to be used to concentrate a solution possessing a negligible boiling point elevation from 5% solids to 40% solids. The 40% liquor is quite viscous and the 5% solution is at 180F, so as a mixed feed, in order II-III-I is to be used. The steam available is at 250 F and a vacuum corresponding to 110 oF is maintained in the last effect. It is to be expected that the overall heat transfer coefficients are 300, 500 and 400 BTU/hr-ft2-0F in the 1st, 2nd and 3rd effects, respectively. The specific heat of the solution can be taken as 1, the condensate all leave at condensing steam temperature and radiation is negligible. Calculate the pounds of 5% liquor that can be concentrated per hour and the steam economy that can be expected.