Modeling Potassium Capture by Aluminosilicate, Part 1: Kaolin

Additives rich in Si and Al such as kaolin may be applied PF biomass boilers to fix alkali metals species that are more benign than the salts released combustion. In this study, models for reaction of gas-phase potassium with particles developed conditions appearing short residence times, high temperatures, small size additive particles. The between gaseous components has been modeled a shrinking core model (SCM) uniform conversion (UCM). SCM takes into account effects chemical kinetics, diffusion gas film surrounding particle, product layer, thermochemical equilibrium on progress. UCM covers particles, equilibrium. Both able accommodate change temperature, particle size, time, component concentration. Literature data from experiments an entrained flow-reactor (EFR) at 800–900 °C were used derive kinetic rate coefficients KOH. then evaluated against experimental KCl, KOH, K2CO3, K2SO4 covering temperatures 800–1450 °C, sizes 4–14 μm, times 0.8–1.9 s, salt/additive molar ratios 0.05–0.96. evaluation indicated both suitable wide range conditions, but captured effect better. modeling outcomes suggested if time was long enough, would major limitation capturing by concentrations. At lower however, mainly limited kinetics. mass-transfer less critical under investigated conditions. can local relevant using biomass.