Thermokinetic Investigations of High Temperature Carbon Capture Using a Coal Fly Ash Doped Sorbent

摘要

Carbon capture (CC) employing novel sorbents at high temperature is highly significant to address the serious concerns of global warming. In this work, thermodynamic and kinetic studies have been conducted on the carbonation using doped sorbents of CaO-MgO-CFA (coal fly ash). The thermodynamic estimations not only proved the feasibility and spontaneity of the reaction but also reinforced the positive role played by CFA in not only enhancing the CC but also reducing the regeneration temperatures. Regarding the kinetic studies, a model has been proposed for both the reaction and diffusion kinetic control regimes and has been validated with experimental data at optimal conditions. Various kinetic and Arrhenius parameters have been estimated and compared with the reported values. The rate constants at 650 degrees C and activation energies estimated for reaction and diffusion controlled regimes were 2.5 min(-1),13 kJ/mol and 0.8 min(-1), 30 kJ/mol, respectively. Our values clearly indicate the enhanced rate achieved by doped sorbents along with thermal stability and also show that kinetics are strongly dependent on the nature of the sorbent along with process conditions.