Reduction Kinetics of Ilmenite Ore as an Oxygen Carrier for Pressurized Chemical Looping Combustion of Methane

Abstract

Reduction kinetics of ilmenite ore as an oxygen carrier for methane chemical looping combustion under elevated pressures was studied using a pressurized thermogravimetric analyzer (PTGA). The reduction phase of the experiments was carried out in a mixture of methane and nitrogen with carbon dioxide and/or steam to simulate an actual combustion environment. The oxidation phase of the experiments was carried out with air. Effects of the temperature (1123–1223 K), total pressure (0.6–1.6 MPa), methane partial pressure (0.23–0.64 MPa), and particle size (45–300 μm) were studied. Tests were also carried out to examine the effect of higher redox cycle numbers on the performance of ilmenite ore. The results showed that increasing the total pressure reduced the rate of conversion during ilmenite ore reduction, e.g., when the total pressure increased from 0.9 to 1.6 MPa, the reduction conversion rate decreased by 6–14% depending upon the reaction temperature because the negative effect of the pressure was less pro...