Production of bio-phenolic chemicals, green diesel fuels, and renewable hydrogen/methane gases from Kraft lignin and “Black Liquor”
The use of fossil fuels for energy and chemical production is not sustainable, and it leads to increased emissions of air pollutants (SO2 and NOx) and greenhouse gases. It is thus of strategic significance to explore alternatives to fossil resources for both energy and chemicals production. Among all the potential alternatives to fossil resources, biomass is promising because it is renewable and immense. Canada is blessed with 401.9 million hectares of forest, approximately 10% of the world’s total forest cover. Forestry residues and wastes (such as harvesting residues, sawdust, wood waste and bark) and pulp/paper by-products (such as “black liquor” and lignin) can be a promising renewable source for energy utilities and chemical feedstocks if novel economically viable processes are developed. Lignin is the second most abundant natural renewable polymer after cellulose and accounts for between 15 and 40% of wood stem. It is produced as a by-product of paper pulping, where it is considered a waste product and currently utilized mainly by direct combustion in the recovery boilers for heat generation. Conversion of lignin/black liquor into high value chemicals and fuels that are conventionally derived from fossil fuel resources will yield both economical and environmental dividends. The proposed Mitacs-Accelerate project aims to (1) develop a cost effective process to produce bio-crude oils directly by hydrolytic degradation of black liquor or crude lignin under hot-compressed water conditions, (2) upgrade bio-crude oils derived from lignin or pyrolysis oils from forestry residues into liquid transportation fuels or alternative feedstocks for a conventional petroleum refinery by hydro-de-oxygenation (HDO), and (3) convert aqueous biomass (carbohydrates, acetic acids, etc.) and aqueous waste products derived from forestry biomass (wood and forestry residues) to hydrogen and methane (as substitute natural gas, SNG) via catalytic supercritical water gasification (SCWG).