Conference Dates

July 1-6, 2007

First Page



Molecular modelling approach was utilized to describe detailed fouling mechanism caused by crystallization. The interest was on the heat transfer surfaces, which were manufactured from titanium and stainless steel. With ab initio calculations, the role of the surface oxide layer structure of titanium and stainless steel on fouling was investigated. The surface structure of titanium and stainless steel were assumed to consist of rutile (TiO2) and dichromium trioxide (Cr2O3), respectively. It was found that the inorganic fouling depends strongly on the oxide layer structure and the existence of hydroxyl groups on the surface. Based on the results, two mechanistically different fouling categories were found. When the surface hydroxyl groups exist, the fouling can take place via condensation reactions with species containing hydroxyl groups. On surfaces without the surface hydroxyl groups, fouling takes place preferably via adsorption of ions.