Particles attrition of binary mixtures in the coal-fueled chemical looping system based on fluidized bed

Abstract

In this work, a reactive air jet attrition device with auto-recording and collection of elutriated fines was developed. Results established insights into the physiochemical interaction and further correlated attrition behaviors between char and oxygen carriers under various operation modes. The attrition rate increased by over 110% upon the introduced CO2, which brought in the significant effect of thermochemical stress, similarly in effects of the increased char addition ratio and the decreased sizes of char or hematite in different extents. For the char-hematite co-attrition process, the elutriated carbon loss of char with poor mechanical strength was found to be over 10%, while the reactive iron loss of hematite was found to be 6.3%, and was enriched in elutriated fines. The reaction-derived thermochemical stress and the collision-derived mechanical stress jointly controls the particle attrition during the cyclic transformation of oxygen carrier particles in coal-fueled chemical looping fluidization, especially significant in its reduction stage.