Investigation of the co-pyrolysis characteristics and gas emission properties of spent bleaching earth and biomass in a thermogravimetric analyser and a fixed bed reactor

Abstract

The co-pyrolysis of spent bleaching earth (SBE) for adsorption decolorization and biomass can promote the resource utilization of industrial waste. The thermal behaviour and kinetics during the co-pyrolysis of SBE with sawdust (SD) were comparatively evaluated with thermogravimetric analysis at different mixing ratios and heat rates. Activation energies corresponding to the different conversion rates were determined by the distributed activation energy model (DAEM). The pyrolysis yield and evolved gases were measured by a fixed bed pyrolysis system. The results demonstrated that as SBE increased, the activation energy during the initial stage of pyrolysis clearly decreased. The fixed bed isothermal pyrolysis experiment showed that the increase in SBE had a significant effect on the gas production components, resulting in a decrease in CO and CO2 yields and an increase in alkane content. At 800°C, the addition of 30 % SBE had the highest H2 yield, indicating that SBE is a valuable additive.