Conference Dates

May 18-22, 2003

First Page



Deposits formed on the surface of heat treatment equipment in the dairy industry compromise product quality and process efficiency. Frequent cleaning is needed to ensure consumer safety and optimal process operation. Cleaning solutions generally have a high environmental impact; the need is to minimize their use. We have studied the physics and chemistry of cleaning at two length scales of measurement: (i) the effect of cleaning chemical and water on deposits within a plate heat exchanger (PHE), and (ii) the effect of process variables on small fouled disks. The chemical nature of cleaning of dairy deposits is shown clearly by the effect of using pulses of water within a PHE cleaning cycle: cleaning stops for proteins, in contrast to the cleaning of starch pastes from surfaces. Different modes of cleaning can be identified from cleaning of the disks, and effects of physics and chemistry can be separated to some extent.