Validated scale-up procedure to predict blockage condition for fluidized dense-phase pneumatic conveying systems
This paper presents results of an ongoing investigation into modelling fluidized dense-phase pneumaticconveying of powders. For the reliable design of dense-phase pneumatic conveying systems, an accurateestimation of the blockage boundary condition or the minimum transport velocity requirement is of sig-nificant importance. The existing empirical models for fine powder conveying in fluidized dense-phasemode are either based on only a particular pipeline and product or have not been tested for their accuracyunder a wide range of scale-up conditions. In this paper, a validated test design procedure has been devel-oped to accurately scale-up the blockage boundary with the help of a modelling format that employs solidsloading ratio and Froude number at pipe inlet conditions using conveying data of two different samplesof fly ash, electro-static precipitation (ESP) dust and cement (particle densities: 2197–3637 kg/m3; loose poured bulk densities: 634-1070 kg/m3; median size: 7-30 um). The developed models (in power func-tion format) have been used to predict the blockage boundary for larger diameter and longer pipelines (e.g.models based on 69 mm ID x 168 m long pipe have been scaled up to 105 mm ID and 554 m length). The predicted blockage boundaries for the scale-up conditions were found to provide better accuracy compared to the existing models.