Study on the feeding characteristics of pulverized coal for entrained-flow gasification

In this paper, the experimental activity was carried out on five pulverized coals with different particle sizes taken from the industrial demonstration plant of SE-Gasifier Pulverized Coal Gasification in Nanjing, China. Flow properties of pulverized coal including powder cohesion, angle of internal friction and tensile strength were determined by the rotational shear cell accessory of Freeman FT4 Powder Rheometer. These pulverized coal samples were further discharged from a bench-scale discharge system and an industrial device in the SE gasification industrial plant. The effects of mean particle size, fine contents and hopper pressure on the flow properties and the discharge of pulverized coal were discussed. The tensile strength was used to correlate with the feeding characteristics of pulverized coal and proved to be an effective indicator to describe the powder feeding performance. A combination of a continuum approach and a particle-particle approach was therefore built to predict the tensile strength. The model, considered the elastic deformation, was further modified by taking into account the effect of particle size distribution. The predicted tensile strengths were compared with those obtained from the Mohr-Coulomb approach, giving errors mostly below +/- 25%. It was therefore considered as a valuable way to provide reference for the evaluation of feeding characteristics of pulverized coal for entrained-flow gasification. (C) 2019 Elsevier B.V. All rights reserved.