Comparative investigation and analysis of effects of formate salt additives on corn straw pyrolysis

In this work, the effects of formate salts(potassium/nickel/zinc formate) on behavior, yield, and product characteristics were evaluated and compared by using the combination of TGA and the fixed-bed reactor. The results showed that potassium formate had a good catalytic cracking ability , resulting in a forward shift of the decomposition temperature of organic components in biomass and an increase of gas yield. The nickel formate had the strongest catalytic ability for biomass pyrolysis to produce oil. Compared to the non-catalytic pyrolysis, the yield of bio-oil increased about 8 wt%. After adding potassium formate, the generation of phenols in the oil was enhanced, while the presence of nickel/zinc formate obtained the opposite results. The total content of oxygenated compounds(alcohols, ketones, esters and acids) was reduced for all formate salts, and the most signigicant difference among them was that the addition of potassium formate obtained the enrichment of ketones. Moreover, the analysis of gas showed that the yields of CO 2 and CO were increased after adding potassium/nickel formate. The reasons were related to the differences in physicochemical property of catalyst and catalytic ability of metal cation in formate salt. • A comparative study on formate-assisted pyrolysis of CS is performed. • Enhancement of selectivity toward ketones is found by adding potassium formate. • More CO 2 and CO are generated by adding potassium formate and nickel formate. • Effect of potassium formate is most significant among the used formate salts.