This grant provides funding for the development of a process control strategy for the control of moisture content in paper manufacturing. The control strategy will utilize as feedback, estimates of the moisture content of the paper as it is being manufactured. The vacuum dewatering process, in addition to the thermal drying process, will be used as the control actuators. The estimates of the moisture content will be based on surrogate measurements which are measurement of quantities that are more easily measurable than moisture content, but are related to moisture content. To develop this control strategy, constitutive models that govern the water removal process in vacuum dewatering will first be developed. Suitable surrogate variables will be identified and models that describe how they relate to moisture content will be developed. These models will be validated in both static and dynamic dewatering environments. Based on the developed models for dewatering and for the surrogate measurements, algorithms for estimating moisture content will be developed. Control algorithms will then be developed, analyzed, optimized, simulated, and finally, experimentally tested.
If successful, the results of this research will lead to improvement in the quality of moisture content control in paper manufacture. Accurate and uniform moisture content is critical for paper to be curl free, cockle free and not cause printer and copiers to jam. In addition, reduction in energy expenditure is also expected as the energy intensive thermal drying process will be more efficiently utilized. The constitutive models developed in this research will improve the fundamental understanding of vacuum dewatering, which in turn will lead to improved designs for future paper machines.