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There exists an ever increasing demand for coal fly ash stabilized sorbents which are thermally stable up to multiple carbon capture cycles at high temperatures (up to 950 °C). The industrial scale-up of this sorbent’s regeneration is limited by its inherent kinetics and thermodynamics that need to be maneuvered carefully to make it economically viable. In this study, sorbents regeneration kinetic and thermodynamic parameters have been estimated under nonisothermal conditions using thermogravimetric analysis. The Coats and Redfern equation has been chosen to estimate thermokinetic parameters under nonisothermal conditions. The thermodynamic values of Gibbs free energy, entropy, enthalpy, etc., for the synthesized sorbent (CaO50MgO10FA-C40) were compared with the simulated values (HSC software) with and without fly ash. The experimental data of sorbent regeneration was then fit into a suitable kinetic equation, based on the classic grain model and studied at various isothermal calcination temperatures. Sor...

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 °C and activation energies estimated for reaction and diffusion controlled regimes were 2.5 min−1, 23 kJ/mol and 0.8 min−1, 30 kJ/mol, respectively. Our values clearly indicate the enhanced rate achieved by ...

Carbon capture using various technical options, viz., adsorption, absorption, chemical looping combustion, membrane separation, and cryogenic separation in either pre- or post=combustion modes, has been found to be the effective solution to tackle a serious concern of global warming. Although adsorption has been widely employed in carbon capture as a result of its economically and environmentally benign nature, it could not be commercialized as a result of the highly energy-intensive regeneration process involved. The major challenge in carbon capture is its sustainability at a high temperature, therefore enabling an easy integration with power generation to make it commercially viable, and also in the production of hydrogen using sorption-enhanced steam reforming. In this work, various combinations of sorbents based on CaO, MgO, zeolites H-Beta and H-ZSM 5, and Al2O3 with and without doping of coal fly ash (C and F types) have been employed in carbon capture using a lab-scale fixed-bed reactor system. Af...