The present invention relates to a demulsification additive composition for demulsification of water-in-oil emulsion caused due to wash water in the crude oil, wherein the composition comprises: (a) one or more demulsifiers (the component (a)); and (b) a compound selected from the group comprising glyoxal, neutralized glyoxal, glyoxal derivative and a mixture thereof (the component (b)), and (c) further comprises phosphoric acid (the component (c)). The present invention also relates to a method of using the present demulsification additive composition for demulsification of water-in-oil emulsion caused due to wash water in the crude oil.
The present invention also relates to a method for demulsification of water-in-oil emulsion caused due to wash water in the crude oil by employing the present demulsification additive composition.