Examining SrCuO2 as an oxygen carrier for chemical looping combustion

Abstract

This paper contains the results of research work on chemical looping combustion (CLC). CLC is one of the most promising combustion technologies and has the main advantage of producing a concentrated CO2 stream, which is obtained after water condensation without any energy penalty for CO2 separation. The objective of this work was to study the chemical looping reaction performance for a novel spinel-type oxygen carrier. The SrCuO2 was tested for the purpose of CLC for power generation, and hydrogen was utilized as a syngas component. SrCuO2 was prepared as a powder. Reactivity tests were performed under isothermal conditions for multiple redox cycles using a thermogravimetric (TG) analyzer (Netzsch STA 409 PG Luxx). For the reduction, 3 % H2 was used, and for the oxidation cycle, air was used. The effect of both reaction temperature (600-800 °C) and reducing/oxidizing cycles (five cycles at each temperature) on the reaction performance of the oxygen carrier samples developed in this study was evaluated. The stability, oxygen transport capacity and reaction rates were analyzed based on experimental TG data. The material was systematically investigated by scanning electron microscopy, X-ray diffraction measurements, N2 porosimetry, particle size distribution and studying the melting behavior. Investigation of the oxidation/reduction behavior of SrCuO2 showed stable chemical looping performance, with great recyclability after continuous multiple redox reactions maintaining the chemical properties. Moreover, excellent oxygen capacity was maintained within cycling combustion tests. Furthermore, the oxygen carrier sample attained a high melting temperature, which provides attractive thermal resistivity. For comparison purposes, another Cu-based oxygen carrier was prepared and analyzed in the same manner. The CuO/TiO2 carrier transported similar amounts of oxygen to the fuel, but its stability to reaction was questionable. The promising results obtained from CLC allowed us to conclude that SrCuO2 is possibly a capable and suitable candidate for CLC for power generation.