Concentration of encrusting liquids salt water or effluent - by mixing with liquid possessing higher affinity for tube surfaces

摘要

A method of evaporating a crust-forming or corrosive solution at given pressures and temps. consists of mixing the soln. with a heat transfer liquid which does not boil at these pressures and temps; the heat of the mixt. is utilised for evaporating the soln, the gas expanding at the soln. boiling pressure, and a portion of the heat of condensation is recovered and utilised in a number of heat exchangers for pre-heating the mixt. This recovered condensation heat is transferred through metal heat exchange surfaces, the heat transfer liq. utilised possesses a higher affinity for these metal heat exchange surfaces than the soln, and the mixt. is of such a proportion that the ratio of heat transfer liquid/solution is sufficiently large for the former to constitute the closed phase and the latter the dispersed phase. Pref., in a multi-stage system, this ratio in a given stage is smaller than the ratio of the hotter mixt. supplied to this stage and generating the heat of evaporation. The pref. liquids used are mineral, plant or animal oil, waste oil, synthetic oil, high-boiling organic liquid, dilute waste acids or mixtures of these.