Diffusive mass transfer and protein removal in the alkaline cleaning of a jellylike whey protein fouling layer

Single steps in cleaning a fouled heat exchanger surface eventually determine the cleaning kinetic and thus the overall performance of a cleaning process. Up to date the complex mechanisms of the mutual supportive processes in cleaning are not yet fully understood. This contribution presents a stepwise approach to investigate the individual process steps starting with the diffusion of the cleaning agent NaOH into a WPI gel, studied at stationary and flow conditions. In the experiments, temperature affected both the diffusion step and the subsequent removal but to different extents. This was further specified and it was found that there is an induction time for the release of disengaged proteins, accounting for the speed of the temperature dependent degrading reactions.

Automated summary

The individual steps in cleaning a fouled heat exchanger surface play a crucial role in determining the overall performance of the cleaning process. However, the complex mechanisms of the mutual supportive processes involved in cleaning are not fully understood yet. This study presents a stepwise approach to investigate the diffusion of the cleaning agent NaOH into a WPI gel under stationary and flow conditions. Temperature was found to affect both the diffusion step and the subsequent removal of proteins, but to different extents.