NewsComments Off on The Possibilities of Black Liquor
When making paper and pulp via the so called kraft process, residuals from the wood end up in a by-product called black liquor. Today the black liquor is usually burned for energy and heat at the paper mills, but what if part of it could be used to make transportation fuels instead?
Johanna Olofsson and Pål Börjesson from Lund University, and part of the SusValueWaste project team, have released a report with greenhouse gas calculations for methanol from different industrial byproducts/residues. The report particularly explores the possibilities of black liquor which is suitable for gasification. Because of its reactive properties, other materials could be mixed with it and piggyback on the advantages.
Mixing by-products for better utilisation
By mixing by-products with black liquor in the process of gasification, methanol fuels for ships or cars could be produced. The report presents a study looking at the resulting greenhouse gas emissions of such fuels and compared them to other potential pathways for using the by-products. For instance, crude glycerol, a by-product from biofuel production, could be used in gasification with black liquor, but it could also be digested to produce biogas. Comparisons and evaluations were made for the black liquor and for crude glycerol from biodiesel (RME) production, fermentation residues from wood-ethanol production, and forest logging residues converted to pyrolysis liquid.
New products from by-products
This oversight and related studies shows that it could be possible to blend different by-products with black-liquor and thereby produce methanol fuels. The greenhouse gases from such fuels most often compare well to those of fossil fuels according to current policy goals, but they also vary. It is not certain that the co-gasification route provides a better option for handling the by-products than other processes, especially if intermediary steps are necessary in order to blend them. There is however a potential opportunity to make use of the by-products by connecting different industries and processes, and thereby providing new products.
Waste and other residual materials from industries and households are of increasing value in today’s economy. Substances that have long represented a cost to the economy are now becoming a valuable resource. Exploiting the full potential of these resources requires increased innovation, systemic change as well as better regulation and governance.