Paper360 - March/April 2018 - 50
techlink | LIGNIN
Creating a Lignin Culture
Huge strides have been made in the commercial development of
lignin, but there is a lot more exciting work on the horizon.
Although the "bio" sector of the
forest products industry has been big news
recently, many do not realize that this new path
was actually trod upon more than 30 years ago,
if not longer.
Michael Paleologou is a research leader in the
Innovative Bioproducts Centre of Excellence
at Montreal-based FPInnovations, the world's
largest private, not-for-profit forest research
institute. He led a team that developed the
LignoForce System™ for lignin production from
black liquor. Paleologou says the system was
invented in 2008, although he says, indirectly,
he started the LignoForce work earlier.
He is quick to credit past FPInnovations
(formerly Paprican) researchers such as Jim
Wearing and Vic Uloth, who did pioneering
work in the late 1980s and early 1990s. "This
was followed by work by Jean-Noel Cloutier,
who looked at an electrochemical approach to
recover lignin from black liquor. I greatly benefitted from their work when I started mine."
Paleologou has been with FPInnovations for
30 years and has spent the last 10 focusing on
the issues surrounding the forest biorefinery
concept. With the market in communication
papers in steep decline in the early part of the
century, the Canadian government was eager
to find a way to transform the country's forest
Natural Resources Canada (NRCAN)
provided a lot of funding for research into
"transformative" products. This led to the
lignin project. "We focused at first on lignin
products rather than the process," Paleologou
explains. "We developed the LignoForce process while trying to destroy the smelly sulphur
compounds that come out of black liquor when
it is acidified."
During the initial work at the pilot plant
level at FPInnovations, when the team was
still thinking about new products, Paleologou
says, "The odor was so unbearable, I could not
Fig. 1: Simplified schematic of the LignoForce system for the production of lignin from black liquor.
have accepted the idea of people working in that
environment. When we discovered the solution,
all sorts of other benefits came out."
And the solution is simple: oxygen (see Fig. 1).
Its benefits, compared with air, are many:
* There is no nitrogen deadload in the process.
* With oxygen, temperatures can rise to 140°C
because of the exothermic nature of oxidation
reactions. This helps with the nucleation process of lignin particles so they can filter and
wash well. This is key, Paleologou explains.
* The sulphur compounds are oxidized, but
so are the sugars and other organics. This
results in a lower pH of the liquor so less
carbon dioxide (CO2) is needed to reach the
desired lignin precipitation pH of about 10.
Carbon dioxide is the highest operating
cost-about 50 percent of the chemical costs
in any lignin precipitation process from
black liquor, so any reduction is important,
To evaluate lignin filtration from carbonated black liquor slurries, Paleologou's team
rented a belt filter and a filter press. The former
had been used by other companies to produce
lignin. Paleologou points out that the belt filter
provides a maximum solids content of only 35
percent. The filter press allowed for a solids
content of up to 65 percent in cake form.
That cake could be dried further. In fact, the
higher the solids content, the lower the operating costs associated with lignin drying. "Also,
with the belt filter," Paleologou says, "we noticed
a layer of fiber on top of the lignin, which confirmed the view that lignin might contain a
lot of fiber."
When it came time to scale up to a demonstration plant, the black liquor was filtered to
remove the fiber.
FINDING A GOOD PARTNER
The success at the pilot stage convinced
the team that it had to "go big." At this point,
FPInnovations teamed up with NORAM
Engineering & Constructors Ltd. to build a
demonstration plant. This was accomplished
with support from the Ontario government
through the Centre for Research and Innovation
in the Bio-economy (CRIBE).
"We had worked with NORAM before,"
Paleologou says. "They already had licenses
for several technologies that had been developed
here. In particular, we liked the fact that they
have extensive expertise in process development
and scale-up, with numerous commercial plants
operating worldwide in various sectors."
Also of importance, NORAM has a presence
in Latin America, where FPInnovations would