Phenomenological model of moisture redistribution in porcelain stoneware spray-dried powder stored in silo

Porcelain stoneware powder requires at least 24 h of silo storage to stabilize temperature and moisture content after spray-drying. Homogeneity is crucial to produce dimensionally stable tiles. The objective was to model moisture redistribution in granules of different sizes using phenomenological formulation. An original multiscale approach incorporated segregation into the coupled mass/heat transfer equations. Finite element method numerically solved and accurately estimated moisture content in fines, intermediate, and coarse granules in accordance with industrial data. The starting moisture content difference of 3.19% between coarse and fine granules was reduced to 1.62% and 0.88% for 24 h and 48 h storage times, respectively. Output temperature estimates agreed with measurements (maximum error of 17%). Higher thermal gradients evidenced the cooling effect as moisture content increased in all granules at the wall, observed as condensed water in the actual system. This model could be applied to any material in storage within a center-filled silo.

Schlagworte

Granular material

Mass and heat transfer

Multiscale model

Porcelain stoneware

silo

DDC Class

620.1: Engineering Mechanics and Materials Science

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Phenomenological model of moisture redistribution in porcelain stoneware spray-dried powder stored in silo