Zeitschrift für Bioverfahrenstechnik und Bioprozesstechnik

Lignin for Sustainable Bioproducts and Biofuels

Yasar Demirel

To meet the goal of replacing 30% of fossil fuel by biofuels around 2030, approximately 225 million tons of lignin will soon be produced beside the current production of between 40 and 50 million tons per year in the paper and pulp industry in the U.S. Yet only about 2% of the waste lignin is currently recycled into new products. This is also the case for the rest of the world. One of the efficient routes of upgrading lignin is the fast pyrolysis, in which lignin molecules are decomposed to short chain molecules in the absence of oxygen producing vapor and char. After condensing the vapor bio-oil is formed. Depending on the type of biomass and pyrolysis conditions, bio-oil contains innumerous compounds including hydrocarbons of aromatics, aliphatic, and cyclic that includes phenols, ethers, aldehydes, ketones, carboxylic acids, pyridines, amines, and esters. Separation of phenols from lignin with polyaromatic nature can help achieve renewable, sustainable, and economical phenols, other chemicals, and fuels from lignin. Since approximately 99 % of current phenol production originates from petroleum-based Cumene oxidation with rather low yield, lignin pyrolysis bio-oil can help reduce the dependence to fossil fuels for producing chemicals and fuels.