Cleaning of solid behenic acid residue from stainless‐steel surfaces

A rotating disk apparatus was used to study the removal of C14 labeled docosanoic (behenic) acid from stainless steel. The liquid cleaning behavior was studied as a function of temperature, surface morphology, and fluid flow. A mass‐transfer model was proposed to describe the removal of behenic acid from stainless steel using a rotating disk apparatus. The cleaning rates computed from the mass‐transfer model were compared with experimental observations; it was found that at low temperatures the removal was a function of rotation speed. At higher temperatures, however, the removal rate was independent of the disk rotation speed. In some cases the predicted rate of behenic acid removal differed significantly from the observed data. A plausible explanation for these variations is that the residues are removed by the combined effects of dissolution and the shearing of large clusters of solid behenic acid crystals. The temperature‐dependent behavior of the cleaning data was analyzed using an activation‐energy‐based model.