Calcination Thermokinetics of Carbon Capture Using Coal Fly Ash Stabilized Sorbent

Abstract

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. Sorbent calcination conversion efficiencies with model fit have been studied in packed-bed reactor under CO 2 partial pressures ranging from 0 to 100 kPa and at various calcination cycles of the sorbent. A table of comparison has been presented on sorbent regeneration activation energies of reported and experimentally estimated values in this work.