Decomposition kinetics of alkaline earth carbonates by integral approximation method

Abstract

The decomposition kinetics of four synthetic alkaline earth metal carbonates (MgCO 3 , CaCO 3 , SrCO 3 and BaCO 3 ) was studied under non-isothermal conditions from thermo-gravimetric measurements as compared to. The integral approximation method of Coats and Redfern was used to determine the kinetic parameters for the decomposition processes. The decomposition reactions followed mostly first order kinetics and the activation energy of the decomposition reactions increased with the increase in the molecular mass of the carbonates. The change in enthalpy for the decomposition processes was also calculated and compared with the activation energies for the decomposition processes. The activation energy of the decomposition process for all the carbonates was higher than the enthalpy of the reaction excepting SrCO 3 Keywords: decomposition, alkaline earth carbonates, non-isothermal kinetics, thermogravimetry. Resumo A cinética de decomposição de quatro carbonatos sintéticos de metais de terra alcalina (MgCO

Oxygen transport properties of tubular Ce0.9Gd0.1O1.95-La0.6Sr0.4FeO3−d composite asymmetric oxygen permeation membranes supported on magnesium oxide

“…Formation and decomposition of SrCO 3 is temperature dependent. At temperatures higher than 810 °C SrCO 3 starts to decompose and reaches the maximal rate of decomposition at 960 °C [14]. Therefore, it is anticipated that with increasing the operation temperature, the membrane's performance in CO 2 will gradually become comparable with the performance in N 2 .…”

“…[12] Ce 0.9 Gd 0.1 O 2-d 0.03 0.12 [13] Another important requirement for using the OTM in partial oxidation of hydrocarbons or syngas production or in oxyfuel schemes involving a flue gas sweep is the thermodynamic stability in CO 2 . Most barium and strontium containing perovskites form thermodynamically stable carbonates [14] with CO 2 at OTM operating temperatures (700 -900 °C), which can strongly reduce the oxygen surface exchange kinetic and especially for thin membranes significantly reduce the achievable fluxes.…”

Thermogravimetric analysis as significant tool for suitability assessment of solid waste destined for processing by thermal desorption

“…The endothermic process taking place at 573 °C, (Haynes, 2014;Lønvik and Smykatz-Kloss 1984) unaccompanied by the evolution of carbon dioxide, is characteristic of the transformation of the crystalline modifications of silicon dioxide, which was present in significant quantities in the examined samples. As the heating continues above 650 °C, destruction of the carbonates (Maitra et al, 2008) takes place. The corresponding graphs show endothermic reactions and evolution of carbon dioxide.…”

Effect of Composition, Synthesis Protocol and Pellet Size of Cost Effective Adsorbents Doped with Flyash on Carbon Capture

“…It was reported that the pellet form with CC of 0.52mmolCO 2 /g ads and the optimal pellet size in the range of 2-5mm for effective CO 2 adsorption [7]. MgCO 3 starts decomposing from 300oC and re-carbonation also favors between 300 o C to 900 o C [8]. Calcium and magnesium silicates present in flyash decompose into alkaline carbonates while sintering the carbonated adsorbent of sample A2 and A4.…”