Pulp and paper has long been a cornerstone of Canada’s chemical engineering community, but these days the industry is undergoing a sea change. In the 21st century, cutting down trees merely to extract a single value-added product — cellulose for paper, boxboard and many other uses — seems unacceptably wasteful. Instead, researchers are spending time and money on finding uses for all the other chemicals that can be extracted from wood, including hemicellulose and lignin. The idea of the ‘forest biorefinery’ that would produce many saleable products from a single woody feedstock is getting increasing attention, and will be the subject of a flagship symposium at the 63rd Canadian Chemical Engineering Conference taking place in Fredericton in just a few weeks. But according to Khalid Jasim, Technical and Environment Manager at Howe Sound Pulp and Paper Corporation, the idea of the forest biorefinery is older than many realize.
Jasim recently wrote a letter to ACCN on the subject of forest biorefineries. He begins by describing how the level of interest in the subject has increased in recent years (some links have been added):
The Bioenergy Deployment Consortium has already been established in the US and efforts to establish a similar Biorefinery Consortium in Canada are ongoing. Even Environment Canada is encouraging the move in this direction by modifying their GHG monitoring and reporting requirements.
Over many decades, members of the pulp and paper industry such as Tembec and many others have been involved in and financially benefiting from biorefinery processes. In addition, many forest industry-associated research and development programs have been actively pursuing work in the area. For example, since the late 80s and early 90s, PAPRICAN (Presently part of FPInnovations) has published many articles dealing with the technical and economical aspects of lignin separation.
Recently, the January/February 2013 issue of Pulp and Paper Canada magazine reported on page 30 that Frost & Sullivan explain “lignin could become the main renewable aromatic resource for the chemical industry in the future”, and the article goes further to mention that “the industry is just beginning to scratch the surface for lignin potential”.
Last year, Bruno Marcoccia, director of research and development with Domtar, announced the installation of a LignoBoost lignin extraction system in Plymouth, North Carolina. Marcoccia provided an update on the Metso-supplied LignoBoost project for participants at the International Lignin Biochemicals Conference on June 21. He mentioned that the Plymouth mill will produce 50-100 tons per day of lignin, which will initially be used as a fuel, both by the mill and external customers.
The pages of ACCN have also reflected the growing interest in forest biorefineries. We profiled Lignol Innovations, a British Columbia-based lignol extraction company, in the July/August 2012 issue of ACCN. Nanocrystalline cellulose, another emerging wood product, was the subject of the cover story in our April 2011 issue, and forest biorefineries were mentioned in our award-winning article “Nature’s Industrialists” from the November/December 2012 issue.
But if we’re talking about extracting valuable chemicals from wood pulp, there’s one chemical that’s so ubiquitous it often gets overlooked; in fact, there’s a good chance that you may have consumed it several times already today. Give up? It’s vanillin, originally isolated from vanilla beans, but also plentiful in wood pulp. As Jasim explains, it was the Canadian pulp and paper company Domtar that first discovered how to extract this fragrant chemical from wood pulp (links have been added):
Based on the work carried out by G.H. Tomlinson II and H. Hibbert at McGill University regarding the formation and manufacture of Vanillin from waste sulfite liquor(1,2,3), Domtar’s (previously Howard Smith until 1963) Vanillin Plant went into production in May 1937 (4) , the first in the world to recover vanillin from acid sulfite lignin on a commercial scale. This Domtar vanillin process was based on the research and development work lead by Dr. George Tomlinson II (founder of the defunct Domtar Research Centre in Senneville, Quebec). . . .
Ironically, given last year’s announcement regarding Metso’s contribution to the Domtar Plymouth mill’s lignin separation process, it is significant to point out that Howard Smith Mills Ltd. (presently Domtar) had its own lignin separation process and lignin extraction plan starting in 1942 – 71 years ago!. In 1942 and after years of research, Howard Smith Paper Mills Ltd. (Domtar predecessor) first announced the development of a brand new decorative product using pulp resin based on lignin. In 1946, Dr. George Tomlinson II was awarded a US patent for the process of lignin separation from kraft black liquor.
A paper published in 1997 by University of Victoria chemist Martin Hocking in the Journal of Chemical Education gives a detailed account of how this process worked. One fun fact it contains is that in 1981, 60% of the world’s vanillin came from a single pulp and paper plant in Thorold, Ont. Unfortunately, the process also produced large amounts of sodium sulfide, a corrosive substance which is difficult to dispose of. Today, almost all artificial vanillin is made from the precursor guiacol, which in turn comes from petrochemicals.
The days of wood-derived vanillin may be over, but the story reminds us that wood has a rich chemical diversity and could be the source of many other interesting compounds yet to be discovered or exploited. The researchers presenting at our forest biorefinery symposium might just be the ones who will find the answers.