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Mathematical Models for Improved Wet Pressing Technology
D. Bezanovic
Project description:
In paper production, water is removed from the paper web in two sections. The first one is a press-section, in which water is squeezed out of the paper web and into the felt by applying a pressure pulse, as the paper together with the felt passes through a press nip. Excessive water is removed in the dryer-section, by an expensive and energy consuming process. Therefore, even a small improvement in efficiency of the press-section leads to a significant saving of the energy consumption and, moreover, the total drying time.
This motivates a better understanding of the press-section. Consequently, during the past forty years a lot of research, both experimental and theoretical has performed in order to understand this process. This research led to the development of extended nip presses, new felts with higher permeabilities, multi-layered felts, application of heat flux.
Still, big challenges remain in order to thoroughly understand the pressing process. Additional knowledge need to be acquired for the influence of the air, mechanical behavior of the paper web, magnitude and the direction of flow, etc.
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