Product regulation of potassium catalyzed pyrolysis of Chinese Baijiu grains: Towards the production of combustible gases and the reduction of tar formation

Abstract

Engineering-scale conversion and utilization of Chinese baijiu grains (BG) is imperative for the sustainable development of Chinese Baijiu industry. In this study, we developed a facile catalytic pyrolysis of BG using potassium acetate and investigated the proportions of the solid, liquid, and gaseous products at different temperatures and catalyst loadings. Both parameters affected the product proportions, and the highest combustible gas content (83.3 % of total gaseous products) was observed with 1.0 mol/L potassium acetate at 800 °C. The catalyst also affected the proportion of liquid products. In particular, the bio-oil quality improved and the tar content decreased owing to a decrease in long-chain aliphatic acid and ester contents (<10 % of the total liquid products with 1.0 mol/L potassium acetate at 800 °C) and an increase in hydrocarbon content. In addition, the oxygenated groups in the biochar obtained after pyrolysis were bonded to K via K–O bonds, thus making K@biochar a good controlled-release potassium fertilizer. We believe that our catalytic strategy, which has the abovementioned multiple favorable outcomes, could promote commercial-scale valorization of BG.