Transformation and Reactivity of a Potassium Catalyst during Coal–Steam Catalytic Pyrolysis and Gasification

The transformation of potassium catalyst during coal pyrolysis and steam gasification has been studied in a fixed-bed reactor. The gasification residues were obtained by leaching in the water and drying in an oven. The crystallite constituents and ash constituent of the gasification residue were identified by X-ray diffraction (XRD) and X-ray fluorescence (XRF). The results showed that potassium aluminum silicate crystallites were derived from the interaction of potassium with mineral matter. The amount of reduced potassium in the gasification residue was measured by adding steam at low-temperature conditions. The transformation of potassium catalyst and amount of metallic potassium intermediate were determined during pyrolysis and gasification. The amount of K2CO3 pyrolysis residue decreased as the pyrolysis temperature increased, and the reaction activity increased as the amount of reduced-state potassium increased.