Model for attrition in sorption-enhanced chemical-looping reforming in fluidized beds

A jet attrition model is developed to predict the evolution of the particle size distribution in fluidized beds. This model predicts changes in particle size distribution due to impact attrition in the jet region as a function of operating parameters – temperature, particle impact velocity and time. The model provides good agreement with experimental results for iron and hematite as oxygen carriers, with limestone and lime as CO₂ sorbent at temperatures from 20 to 800 °C and jet velocities from 59 to 221 m/s. It is found that fragmentation, abrasion, and material fatigue over the attrition duration must be considered. Two fitting parameters considering fatigue by material properties and repeated collisions are applied in this model, with their values determined based on nonlinear least squares regression following the evolution of the particle size distribution.