Disclosed is a method for recovering and re-employing ionic surfactants
from solutions, dispersions and emulsions of water and liquid hydrocarbons, by
the addition of a second non-aqueous polar phase and an inorganic salt which changes
the ionic strength of the surfactant and causes the surfactant to partition principally
into the non-aqueous second polar phase. More specifically, the method applies
to recovering hydrate growth inhibitor/modifying compounds, with cationic surfactants
such as ammonium, phosphonium and sulphonium alkylated compounds from the effluent
of hydrocarbon production wells; the effluent including water, hydrate inhibitor
compound, at least one additional polar solvent and inorganic salt. Sufficient
additional ions of inorganic salt, and if necessary, an alcohol/glycol are added
to the effluent to form a second polar phase that is less polar than the aqueous
phase, into which the hydrate inhibitor can then dissolve and be separated from
the effluent.