Plastics, detergents, paints, medicines, cosmetics and thousands of other useful products today are made from chemical compounds derived from petroleum. But those compounds could, at reasonable cost, be made from wood instead, say researchers at the University of Leuven. This switch would bring down carbon dioxide emissions, according to their results published in Science.
Wood has three main components: the carbohydrates cellulose and hemicellulose, and lignin, a polymer that holds the fibers in wood together. “In the paper industry, lignin is seen as a residual product and usually burned,” said Bert Sels, director of the center for surface chemistry and catalysis at KU Leuven “That’s a pity, since just like petroleum, it can have many high quality uses if it can be properly separated from wood and the right chemical building blocks are extracted.”
In 2015, the researchers reported a novel chemical process to convert the lignin and cellulose in sawdust into the valuable chemicals and hydrocarbon chains that are used as building blocks for chemical products. That work was done in the laboratory, and it wasn’t clear whether translating it to an industrial scale can be costlier than using petroleum.
Now the team has detailed the design of an integrated biorefinery that converts 78 percent of the weight of birch into useful chemicals. The process involves separating wood into a solid cellulose paper pulp and a liquid lignin oil. The pulp can be used to make biofuels or natural insulation, while the lignin oil can be processed into chemical building blocks.
To calculate the economic viability of the process, the Belgian researchers worked together with a Belgian-Japanese ink company, since some compounds derived from lignin can be used to make ink. The team assessed whether they could use lignin-based compounds to make chemicals currently made with petroleum.
Their calculations show that it can be financially feasible to build and run a biorefinery that converts wood into chemical building blocks. Wood as a raw material could be profitable after a few years, they found.
The team is now in talks with various private industry partners to find more companies to process cellulose pulp and lignin oil. They plan to scale up the production process with the ultimate goal of launching a wood biorefinery in Belgium.
Source: Yuhe Liao et al. A sustainable wood biorefinery for low-carbon footprint chemicals production. Science, 2020.
