文摘
Chemical looping combustion (CLC) is a novel technique, which exhibits the merit of CO<sub>2sub> inherent separation and has been proposed as one of the most promising routes for CO<sub>2sub> capture and sequestration (CCS). The economically feasible and environmentally benign oxygen carrier (OC) is of critical importance for the successful implementation of CLC processes for industrial application. Natural iron ore, known as a kind of particularly cheap mineral material, has been verified as an appropriate OC candidate. However, there are differences among the iron ores with variable contents of active and inert phases, which may eventually result in diverse performance in CLC processes. In this work, CLC performance of hematite from Australia (AH) and China (CH) were systematically compared in a batch fluidized bed reactor, using two low-rank coals: Victorian brown coal (VC) from Australia and Inner Mongolia coal from China as fuels. The results showed that the maximum CO<sub>2sub> yield was 0.92 at 1000 °C under the match of CH OC with VC coal, even though the active phase composition of CH OC was relatively low. It demonstrates that the amount of active phase in OC was not the only determinant for OC selection. Moreover, the reactivity of CH OC was more sensitive to temperature and showed higher reactivity at elevated operational temperature (1000 °C), when comparing with that of AH OC. The inert compounds were significantly conducive to maintaining the porous structure of the OC at high temperature. The results are useful for the design and optimization of a CLC plant, and the application of CH with VC was found to be the optimum match in in situ gasification CLC (iG-CLC) among all the tests.