Experimental study on high concentration entrainment of ultrafine powder

High concentration entrainment of ultrafine powder could strengthen the preparation of ultrafine products in a suspension bed, which can significantly reduce production costs, save energy, and improve productivity in certain industry fields. The ultrafine powder possesses extremely high surface area which can strengthen gas-solid chemical reactions on the particle surfaces, however, it also can easily make particles more agglomerate, resulting in entrainment hard to achieve. The objective of this study was to gain deeper insight into the fulfillment of high concentration entrainment of ultrafine powder. Coarse particles (Geldart B) were mixed to help break the aggregates formed by ultrafine particles and promote the entrainment of ultrafine powder. Additionally, the combined effects of vibration intensity (Gamma) agitation rate (omega), fluidization number of silicon particles (N-si), and the ratio of static bed height to diameter (H) on entrainment were also studied using orthogonal method. What's more, the optimal mass ratio of powder to gas (lambda) reaches 0.228 at ambient temperature. which is 3 times more than the results of our previous researches. The increase in gas temperature (T) is theoretically detrimental to entrainment due to the increased surface forces and enhanced agglomeration. However, by adjusting T to 443 K which is 50% higher than ambient temperature can further increase lambda to 0341. In this paper, the mechanism and roles of the above factors on entrainment are investigated and the temperature effect is analyzed as a focus. (C) 2018 Elsevier B.V. All rights reserved.