FIELD: crude oil treatment. SUBSTANCE: in particular, invention concerns profound dehydration and desalting of stable emulsions of high- viscosity high-sulfur oils with high content of suspended impurities. Preparation procedure: surfactant is mixed with polysaccharide, in particular galactomannan, at weight ratio (0.05- 2.0):(0.01-1.0). Resultant mixture is supplemented by modified starch at weight ratio surfactant/galactomannan/starch = (0.05-2.0): (0.01-1.0):(0.1- 3.0) and further by stabilizing additive, notably potassium sorbate and/or sodium benzoate, observing weight ratio surfactant/galactomannan/stabilizing additive = (0.05-2.0):(0.01-1.0):(0.001-0.5) or surfactant/galactomannan/modified starch/stabilizing additive = (0.05- 2.0):(0.01-1.0):(0.1-3.0):(0.001-0.5). Advantageously, thus obtained demulsifier is dissolved to concentration 0.06 to 7.5 wt % in water or in mixture of water with glycol or aromatic alcohol C1-C3 at vigorous stirring. This composition is added to oil emulsion at vigorous stirring in mill-type mixer. EFFECT: increased efficiency of multifunctional demulsifier. 5 cl, 20 ex
