Cutting crude behaviour
15 Jan 2000
Fouling on surfaces occurs widely in the process industry. Effective process plant cleaning is necessary, but even if cleaning is automated it is rarely optimised. The removal of oil films from metal surfaces is a common problem in the metal finishing and oil transportation areas.
Michael Bird and Sam Espig have just completed a three year project at Bath on the removal of crude oil films using aqueous detergents. The project was supported by the EPSRC and International Products Corporation, New Jersey, US.
Bird and Espig constructed a rig which enabled stainless steel test pieces to be fouled and cleaned in situ.
They investigated a range of alkali, surfactant and chemical cocktail cleaners and found that an alcohol ethoxylate (an anionic surfactant) was the most effective cleaning agent. Cleaning was investigated as a function of detergent, concentration, temperature and flow.
Visual observation of the cleaning process enabled Bird and Espig to find the mechanisms of oil deposit removal. The process was also described mathematically, to find the rate limiting step.
A substantial amount of previous research, at other centres, concentrated on surfactant formulation chemistry for cleaning applications.
Before Bird and Espig's work little was known about the practical situation of surfactant cleaning, the importance of thermo-hydraulics and mechanisms of oil removal.
Bird told PE: `As a result of this project we have the prerequisite knowledge needed to optimise industrial oil cleaning to minimise cost, downtime or environmental impact.'
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