Evaluation and Development of a Prototype Electrokinetic Sonic Amplitude (ESA) System for On-Line Measurement of Charge in Papermaking Process Streams

The papermaking industry uses an abundance of chemicals to control the process of papermaking. These chemicals are used to control everything from paper strength to brightness. Due to the natural variability of products used in papermaking, the chemistry of the process is heavily monitored. Cationic (charge) demand is one of the most important parameters in process control of papermaking. High variations in cationic demand result in off-spec final product or paper breaks resulting in wasted production and downtime. Both of these results are costly for papermakers due to higher energy consumption and loss of revenue. Currently, cationic demand is measured off-line in a laboratory setting with a heavily diluted specimen taking up to hours for results. The industry need is for an on-line, real-time measurement of cationic demand at higher consistencies to provide control feedback for the addition of cationic polymers for finely-tuned control of the paper process. Electrokinetic sonic amplitude (ESA) is a method for measuring particle charge and size, which has been employed in the semiconductor industry for several years. While this technology is generally geared for smaller particles (micron size) instead of paper fibers (millimeter size), this project researched the idea of using ESA to measure cationic demand in a real-time setting at high pulp consistencies. Within the scope and schedule of this project, the feasibility of the ESA technology for use in an on-line instrument was inconclusive. Further engineering is required to generate a sufficient ESA signal from the paper pulp to obtain reliable and consistent measurements. Future research in this area will help to further tailor the technology for application to paper streams. The ESA technology continues to remain a viable option for on-line charge demand measurements in the papermaking process and future research should continue in this area to address technical and mechanical issues associated with its implementation.