Investigation of the properties and composition of a concentrate of spent Inkam-1 emulsion as a corrosion inhibitor

Abstract

The processing of discharge cutting fluids by membrane methods yields a concentrate consisting of petroleum products and surfactants. A gas chromatography–mass spectrometry study of the chemical composition has revealed the presence in the concentrate of dicyclohexylamine, which is a corrosion inhibitor according to published data. Therefore, it has been proposed to use the concentrate as a steel corrosion inhibitor for oilfield equipment. The physicochemical properties of the inhibitor have been determined, and corrosion tests for steel of Steel 20 grade have been carried out using the gravimetric method. To improve the protective properties of the inhibitor, the spent-coolant concentrate has been treated with a 1 M NaOH solution (to increase the pH) and modified by admixing oxypropylated diethylene glycol. According to the testing data, the degree of protection of Steel 20 was 78.5%. The resulting concentrate can be used as an inhibitor to protect pipelines against the corrosive effects of formation water. The composition of additives that can enhance the inhibitory characteristics of the concentrate has also been determined by testing.