Effect of calcination/carbonation and oxidation/reduction on attrition of binary solid species in sorption-enhanced chemical looping reforming

The effects of chemical reactions on the attrition of oxygen carrier particles and CO2 sorbent based on a chemical looping reforming (CLR) process with intrinsic CO2 capture were analyzed. Iron/hematite as an oxygen carrier, and limestone/lime as a CO2 sorbent were tested in a jet attrition apparatus. Attrition tests were conducted with particles of a single species and with binary solid mixtures, for different temperatures, different gas species and ranges of gas concentrations, varied to the reactions. Material properties were measured to investigate how the chemical conversion of particle species affects the attrition in both single-species, and two-species environments. Iron oxidation decreased the particle crushing strength, forming a porous iron oxide layer on the surface. When hematite was reduced with CH4, the proportions of reduced iron oxides increased the intrinsic crushing strength on the surface. For limestone, calcination increased the attrition due to a decrease in the intrinsic particle crushing strength. Lime carbonation reduced attrition because of increasing ductility and sintering, as well as the formation of a limestone surface layer of carbonate. Particle attrition increased when two solid species were mixed together, due to the increasing frequency of inter-particle collisions.