The effects of Calcium deactivation on the measurement of activation energy in char-CO2 gasification

Abstract

CO2 gasification of calcium-rich lignite and coffee char are conducted via thermogravimetry analysis (TGA) at 1098–1173 K and 0.025–0.1 MPa CO2. The effects of calcium deactivation on determining the activation energy are assessed in detail. Results reveal that the calcium deactivation increases the value of the activation energy. The activation energies of the lignite char (LC) and coffee grounds char (CGC) with Ca deactivation are significantly increased compared with those of CGC and LC without Ca deactivation, and the relative errors are between 4.5% and 23.4%. To measure the activation energy without Ca deactivation in char-CO2 gasification, the lower CO2 pressures and higher temperatures should be selected according to the equilibrium regularity of CO2 over CaCO3.