Proving Lignin’s Potential

A pilot plant in Canada extracts lignin from black liquor
By Erin Voegele | June 17, 2011

Lignin can be produced as a byproduct of the chemical pulping process. According to nonprofit research institution FPInnovations, the potential market for lignin-based products is massive. The material can be used as a renewable replacement for many substances traditionally derived from petroleum, including fuels, resins, rubber additives and thermoplastic blends.

In order to provide potential buyers of lignin with samples, FPInnovations has partnered with the Centre for Research and Innovation in the Bio Economy, Natural Resources Canada (RCAN) and AbitibiBowater to develop a black liquor and lignin evaluation center in Thunder Bay, Ontario, Canada. The core of the center is a lignin demonstration plant that ties directly into the black liquor stream of AbitibiBowater’s kraft pulp mill. When fully operation, the demonstration plant will produce up to 100 kilograms (220 pounds) of lignin per day. The resulting byproduct will be supplied to research and development labs for evaluation.

According to Tom Browne, FPInnovations’ program manager for the biorefinery, the basic process employed by the demonstration plant was actually employed commercially in the 1940s. A revamped and improved technology is now being employed in the demonstration plant. Browne notes that he cannot discuss the details of the technology improvements due to pending patents, but does say the process essentially precipitates lignin out of black liquor, which is the spent cooking liquors that result from the kraft pulping process that is used commonly in the pulp and paper industry.

Although the process employed by the demonstration plant is specifically designed to extract lignin from black liquor, other lignin extraction processes will likely be employed at cellulosic biorefineries in the future. The work being done by FPInnovations and its partners is designed to help build markets and demand for lignin, which will also benefit other lignin producers.

Browne also notes that lignin extracted from different processes and different feedstocks will have different qualities. For example, the molecular weight distribution will differ and each lignin product will have its own type and level of impurities. “The idea is to match the lignin product to the end users’ needs,” Browne says. “There will be places where a cellulosic ethanol plant makes more sense and other places where you would prefer lignin from a chemical pulping mill.”

“The lignin evaluation plant provides us an opportunity to move wood-based products beyond traditional markets,” says Doug Murray, general manager of AbitibiBowater’s Thunder Bay Operations. “We feel very fortunate to be part of this initiative.”  Frank Dottori, chair of CRIBE, adds that whenever you create alternatives to fossil fuels, you create opportunities that will span generations. 
Erin Voegele