Influence of Alkali and Alkaline Earth Metallic Species on the Phenolic Species of Pyrolysis Oil

Abstract

Bio-oil as an important renewable energy product has been successfully made from corn stalks and lignin via a fast pyrolysis process. This study investigated the effects of alkali and alkaline earth metallic species (AAEMs) on phenolic products in corn stalk and lignin pyrolysis oil. Corn stalks were demineralized with 0.5 M HCl, and lignin was doped with 0.2wt%, 2wt%, and 20wt% KCl and CaCl2, respectively. The pyrolysis experiments were conducted in a fixed bed tubular furnace ranging from 450 °C to 600 °C. It was found that AAEMs exert positive effects on the formation of char and gas and inhibit the production of bio-oil. The effect of KCl on the product distribution from lignin is somewhat stronger than CaCl2. Moreover, the content of P, HP, GP, and SP decreases after removal of AAEMs. KCl can promote the polymerization of light molecular aromatic hydrocarbons to increase the SP yield at 600 °C, whereas the effect on increase in P and HP content is relatively weaker than CaCl2. KCl and CaCl2 play notable roles in demethxylation and demethoxylation in increasing phenol content and removing the R group from the ring.