Concentrating aq. effluents contg. calcium sulphate and glycerol - by spraying into hot gas stream, using insufficient heat to cause complete drying

摘要

A mixt. of effluent water and waste prods. is concd. to a dry solids content which is considerably above the satn. point, by spraying the liq. effluent mixt. into a hot gas stream such that the ratio of (a) the difference in heat content of the hot gas on entry to and exit from the system per unit of time and (b) the amt. of heat required for complete evaporation of the liq. phase in the sprayed mixt. in the same period, is 1. The process is esp. useful for treating effluents such as those obtd. in the edible oil and oilseed processing industry, contg. CaSO4 and glycerol. Due to the low concn., combustion of such wastes requires large amts. of energy. Normal evaporators cannot be used due to the satn. phenomena which occur as the concn. of the mixt. rises. Spray drying cannot be used to severe caking which occurs due to the glycerol content of the material.