Drag Reduction Characteristics of Micro-Fibrillated Cellulose Suspensions, 2011 PaperCon Conference

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Drag reduction characteristics of micro-fibrillated cellulose (MFC) suspensions are evaluated in a fully developed turbulent pipe flow. Drag reduction is estimated from pressure drop measurements obtained with a differential pressure sensor mounted on the up- and down-stream ends of a 3.0 m long pipe, part of the 1000 liter, pilot-scale flow loop. Two pipe diameters are considered, namely 45mm and 57mm, with flow rates ranging from 300 – 1000 l/min. MFC concentration has been chosen in the range 0.02 – 0.2% by mass and is compared with the flow of water under identical conditions at room temperature.

In the fully turbulent regime, the rheology of the suspensions is shown to be identical to that of water. Drag reduction is found to increase with flow rate and with MFC concentration up to 0.15%, after which it was found to decrease. A maximum drag reduction of approximately 9% was observed in each pipe. Further, the flow 0.02% MFC suspension increased the drag in the 57mm pipe at lower flow rates. Results from this study may have implications on turbulence damping during forming, energy reduction during paper-making processes and in the design and operation of MFC production.