A diffusion-driven model for deposit removal during water rinse

The objective of this study is to develop a model that is based on water diffusion for predicting the cleaning procedure during water rinse of Clean-in-Place operation. The kinetics of dairy foulant generated by using dairy product was analysed. The foulants removal with three different moisture contents (6.7%, 13.4%, and 39.3%) and four different wall shear stresses (WSS, 0.013, 0.39, 0.84, and 2.42 Pa) were evaluated. It was found that the lag time decreased with increase of WSS. In addition, the maximal removal and cleaning rate was found to increase along with the elevation of the wall shear stress. Moisture contents of the deposit determines the minimum magnitude of the wall shear stress to initiate the removal process. By combining the water diffusion and removal kinetics obtained from the experiment, a model to describe the removal of the deposits has been developed. Diffusion assuming 1-D infinite plate was used to simulate the change in moisture content. The model confirms that the foulants with a higher initial moisture content is more rapidly removed. Furthermore, the foulant removal is affected by the permeation of water into foulants as well as the wall shear stress.