Crud Formation

Crud refers to a viscous interphase layer that forms in many technical settlers, which may or may not affect the settler performance. In process design, in some cases it is impossible to find appropriate operating conditions, where crud formation can be avoided. In such systems, the crud layer may build up over time, which then has to be removed in so-called crud days, where the operation is stopped, the crud removed and treated separately. It has been shown by Ruckes and others that one form of crud is induced by fine solid particles, which have the tendency to adsorb on the drop surface and thus to stabilize the drops in so-called Pickering emulsions. Ruckes also showed that effects of impurities on crud-forming systems are much more pronounced than their influence on solids-free dispersions. While the principal occurrence and behavior of crud has already been characterized by Ruckes, current efforts are directed at a deeper understanding of crud formation, which will be the basis for deriving systematic methods to avoid or to deal with crud.

Publications

• S. Ruckes, A. Pfennig: Untersuchungen zum Einfluss von Mulm auf das Abscheideverhalten organisch- wässriger Stoffsysteme. Final Project Report, 2010. 
• M. Henschke, L.H. Schlieper, A. Pfennig: Determination of a coalescence parameter from batch-settling experiments. Chem. Eng. J. 85 (2002) 369–378. 

Contact(s) : PFENNIG Andreas