THERMOCHEMISTRY OF OXYGEN CHEMISORPTION-DESORPTION ON COAL

Chemical looping combustion of solid fuels has recently received considerable attention as a promising capture-ready combustion technology. An alternative method to overcome the inherent limitations of carrier-based looping combustion of solid carbons was proposed under the name of CarboLoop process [1,2] which was based on the well established role played by surface oxides as reaction intermediates in the combustion of solid carbons [3,5]. An interesting development of this concept in the future energetic scenario could be in the direction of chemical looping gasification. The present work addresses the chemistry and the thermicity of oxygen chemisorption on coal chars followed by desorption of CO and CO2 at higher temperature. The experimental work relies on traditional thermoanalytical and calorimetric techniques, but additionally takes advantage of modern spectroscopic analyses, in particular XPS with syncrotrone radiation, to disclose the evolution of functional groups present on the surface of char throughout oxidation and thermal desorption..