Evaluation of calcium chloride for synergistic demulsification of super heavy oil wastewater

Calcium chloride (CaCl₂) is used together with cationic poly (dimethylamine-co-epichlorohydrin) (P-DcE) and cationic polyacrylamine (CPAM) to demulsify super heavy oil wastewater. A new reverse emulsion breaker (REB) with the optimal ratio of P-DcE to CaCl₂ to CPAM of 20:600:1.2 (m/m) can remove 98.04% mineral oil and 94.48% COD. Compared to P-DcE used alone and P-DcE supplemented with concentrated sulfuric acid to enhance demulsification, the advantages of the REB are high removal rates for mineral oil and COD, low cost, and environmental friendliness. GC-MS indicates that the REB can remove more organic compounds such as mineral oils than other agents and most of the residues are oilfield chemicals such as corrosion inhibitors, scale inhibitors, biocides, and demulsifiers. The REB, which exhibits good efficiency in anaerobic digestion and synergistic demulsification of SHOW arising from CaCl₂, is efficient, safe, and economical. © 2012 Elsevier B.V.