Investigation on iron ore for the oxygen carrier aided combustion

Abstract

By partly replacing the conventional bed materials in the circulating fluidized bed (CFB) with oxygen carrier, the uniform distribution of temperature and oxygen in the CFB can be enhanced by the oxygen-carrier-aided combustion (OCAC) technology, which is of benefit to reduce the NOx emission during the combustion.In this work, the performance of oxygen carrier (OC) is firstly identified and optimized by various mass ratios of OC to SiO2 (Φ), i.e., 0:100, 50:50 and 100:0, and the superficial gas velocity (Ug: 3Umf, 4.5 Umf and 6.0 Umf; Umf is the minimal fluidized gas velocity) in a batch fluidized bed reactor using two kinds of iron ores as OC (the mass fraction of active phase, Fe2O3, are 47% and 90%, defined as 47Fe and 90Fe) in OCAC of Chifeng lignite. Secondly, the effect of the key operational parameter, i.e., air-to-fuel ratio (λ = 0.8, 1.0 and 1.2), on the gas concentrations, carbon conversion, CO2 yield and NO conversion were evaluated during the continuous experiment. At last, the apparent morphology and crystalline phase of used 90Fe is characterized by SEM and XRD, respectively. An improved CO2 yield and low NO conversion are simultaneously achieved by the OCAC technology.