Abstract: A method is disclosed by which vapour is cleaned of gaseous impurities during evaporation of polluted liquids. Vapour is conducted via a boiler, a compressor to a heat exchanger (12) in which condensation takes place. In order to clean the vapour, a scrubber (14) is arranged between the boiler (3) and the heat exchanger (12), in which the vapour is scrubbed in several steps (17, 18) at different pH values. Thus, the step (17) is an acid step, whereas the step (18) is an alkaline step. In this manner, the vapour for condensation may be conducted into the heat exchanger and be condensed in order to remove a clean condensate without pollution of acid or alkaline substances.

Abstract: A method of separating water from an aqueous emulsion using a minimum of energy includes heating the aqueous emulsion in a sump, conveying concentrated emulsion from the sump to a heat exchanger so as to pass therethrough back to the sump, circulating water vapor and non-condensable gases from the sump through a compressor to raise its temperature and passing the heated water vapor and non-condensable gases through the heat exchanger to condense and heat the concentrated emulsion therein and evaporate water therefrom, a thermostat filled with water and water vapor, together with first and second pressure switches respectively communicating with the sump and the external atmosphere and the heat exchanger and the external atmosphere, maintaining a temperature differential between 0.5.degree. and 3.degree. C. between the aqueous emulsion in the sump and the temperature of the compressed water vapor and noncondensable gases.