Cogasification of Crude Glycerol and Black Liquor Blends: Char Morphology and Gasification Kinetics

Abstract

AbstractIn this study, we assessed the feasibility of black liquor/glycerol blends as a potential gasification feedstock. The char gasification reactivity and kinetics were studied at T=750, 800, 850, and 900 °C for 20 and 40 % blends of glycerol with black liquor. Three qualities of glycerol were used including two industrial‐grade crude glycerols. The gasification rates were similar for all blends; therefore, the alkali‐metal catalysis is also sufficient for the char blends (alkali/C atomic ratio between 0.45 and 0.55). The blends with the most impure glycerol (containing K) had the lowest activation energies (∼120 kJ mol−1) and reaction times for char gasification and, therefore, had fuel properties suitable for gasification. The char particles from different blends showed surface morphologies similar to those of black liquor chars with an even surface distribution of alkali elements. A loss of alkali (mainly K) from the fuel blends during pyrolysis indicated the necessity to perform gas‐phase studies of alkali release. Overall, these results encourage the use of glycerol as a potential gasification feedstock for catalytic‐gasification‐based biorefineries.