Environmentally Friendly Emulsion Breakers: Vision or Reality?

Abstract

Abstract With the ever-growing demand for more environmentally friendly oilfield chemicals, classic oilfield chemistries are no longer acceptable and new chemical systems are required. Future oil production will still require efficient dehydration and desalting of crude oil. In addition, the protection of the affected environment will be of increased significance. The industrial availability of ethylene oxide in the 1940s firstly allowed the design of nonionic surfactants for emulsion breaking. With the development of ethylene oxide / propylene oxide block copolymers, the first highly efficient crude oil demulsifers were available. The addition of ethylene oxide / propylene oxide to alkylphenol formaldehyde resins and to oligoamines yielded emulsion breakers that performed sufficiently at low concentrations. To achieve the future requirements of environmentally acceptable oilfield chemicals, emulsion breakers with low toxicity and high biodegradability are needed. Due to the fact that nonionic alkoxylate based polymeric surfactants have in general a low toxicity, biodegradation was identified as the major bottle neck. Above described polyether type chemistries usually show low biodegradation due to their high molecular weights, especially in marine biodegradation tests (OECD 306) which are often required. Alkylphenol resins have an improved biodegradation profile in comparison to the polyether types, but some serious toxicity issues. Polyesters are well known as highly biodegradable polymers with low toxicity and a lot of effort was made to design polyester based demulsifers. This paper describes the development of biodegradable alkoxylated polyester dendrimers for breaking oil/water emulsions.