Techniques for improving mixing quality, PaperCon 2014

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Assessing the quality of additives dosage and subsequent mixing can be difficult. In this work we present a set of techniques which can be used to assess the mixing quality of wet-end as well as assessing flow conditions which can promote and/or be detrimental to mixing quality. In the first part of this work we show how mixing quality can be studied at pilot-scale through studying the addition of cationic blue colour in a paper stock. Here, we show how the addition of cationic blue colour in place of retention polymers during production can reveal both transient and steady state flaws with the dosage and mixing strategy. We also show how more advanced measurement techniques, namely magnetic resonance imaging (MRI) and ultrasonic velocimetry profiling (UVP) can be used to assess non-uniformities in flow conditions which could deteriorate mixing. We also discuss practical and operational considerations when using these approaches.