Presenter: David Workman, Nalco Company, Naperville, IL. Coauthor(s): Thomas Lindley and Brian Ornay, Nalco Company, Naperville, IL.
Water conservation has become part of the industrial landscape. Corporate sustainability goals necessitate that every process be examined, and CIP processes are not exempt. Cleaning and sanitizing of process equipment can account for up to 20% of a plant’s total water use. A key step in the CIP process is the rinse cycle, with its removal of process cleaning and sanitizing chemicals prior to the next stage in the CIP or the re-introduction of product. Accurate determination of the CIP rinse cycle endpoint is problematic with current methods that employ indirect sensors and/or timers to indicate when a rinse stage is complete. These methods often lead to (a) over-rinsing to ensure process cleaning, and sanitizing chemicals are removed, resulting in excess water usage; or (b) an under-rinsed cycle that can compromise product integrity. An inert fluorescent tracer can be introduced into the CIP process to provide accurate determination of rinse stage endpoint. Tracking the tracer concentration decay during the rinse cycle provides a real-time methodology to accurately quantify the removal of the CIP solution being used. The rinse endpoint is then targeted to an acceptable residual CIP solution concentration, which protects product integrity while optimizing water usage by prevention of over-rinsing. Controlling the rinse endpoint based on the direct measurement of a CIP solution component (inert fluorescent tracer) eliminates plant and operational variations (such as tank location, tank volume, flow rate variations, and seasonal water quality changes) from the endpoint determination. Distinct rinse cycle set points are established for both cleaning and sanitizing cycles. Rinse cycle endpoints can be data-logged, and individual CIP Circuits can be tracked and trended to monitor for system characteristic changes that may currently go unnoticed. This new application is built upon Nalco’s 3D TRASAR technology for boilers and cooling towers and 20 plus years of fluorescence experience. The inert tracer is caustic, oxidant resistant, and stable in most CIP process conditions. The detection limit of the tracer is well below FDA guidelines for process additives. Results from a successful implementation at a regional craft brewer will be discussed where >25% decrease in rinse times was noted.
Dave Workman is a staff scientist at Nalco Company in Naperville, IL. During a 20-year career with Nalco, Dave has worked on a variety of water- and process-centric projects, including multiple TRASAR applications. Before coming to Nalco, he received a Ph.D. degree in chemistry from The Ohio State University and completed a post-doctoral study at the Massachusetts Institute of Technology.