EXPERIMENT STUDY OF REACTIVITY AND MORPHOLOGICAL CHANGE OF CAO-BASED CHEMICAL LOOPING PARTICAL IN CYLIC CARBONATION-CALCINATIOIN REACTIONS

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2013-05

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The Ohio State University

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The essence of The Ohio State University (OSU) Chemical Looping Processes (CLPs) is cyclic gas-solid reaction. CaO-based cyclic reaction is one of the basic OSU CLPs. Reactivity and recyclability of solid reactants are two major issues which are deteriorated through the morphological properties of solid reactants in the cyclic CaO-CO2 reactions. Particle development is mostly focused on optimizing fresh morphological and anti-sintering properties. The goal of this study is to investigate the deactivation mechanism of CaO-based calcium looping particles. The reactivity of “Fresh CaO” and “Sintered CaO” are compared through varying reaction time to study the effect of time on the resulting particle reactivity. The effect of reaction temperature on CaO is studied by comparison between 700℃ and 800℃ sintering in Thermo Gravimetric Analyzer (TGA). Through comparing the CO2 capture capacities, the surface area and pore volume of CaO after three and six reaction cycles with Surface Area & Pore Size Analyzer (BET), the effects of cyclic CaO-CO2 reactions can be found. Ionic diffusion through the calcite layer during the reaction of CaO and CO2 is also studied through analyzing the cross-section area of partially-reacted CaO tablets through the Scanning Electron Microscope (SEM) and Energy Dispersive X-Ray analysis. The data shows that, non-structural ion (CO32-) is the dominating ion in the CaO-CO2 cyclic reactions and particle development should focus on improving the initial morphological properties. Cyclic reaction is an independent factor which deactivates solid reactivity, which is against the understanding that solid deterioration was almost unanimously caused by the sintering effect in the previous studies.

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ionic diffusion, multiphase reactions, inert marker experiment, interface, particle formation, environment

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