The Resilience of Kraft Process and its future

Source: PA Archives

Roger Gaudreault
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Some background context

The Kraft pulping process, patented in 1879 and implemented in 1890, has shown resilience for more than 100 years, as it provides higher pulp strength and allows for about 98% of chemicals recovery cycle and energy efficiency. The 20th century was rich in innovation to the Kraft pro-cess, driven by the need to provide global resource efficiency and lower environmental footprint. These include batch/super-batch and continuous digesters, cold blow, impregnation vessel, ex-tended and modified cooking zone, and bleaching strategies such as oxygen delignification, mul-tistage bleaching tower, the replacement of D/CEDED bleaching sequence by higher level of chlorine dioxide substitution (e.g. D0EopD1), oxygen/ozone/totally chlorine free (TCF) and neu-tral bleaching.

At the end of 20th century, environmental considerations put pressure on the industry to lower total reducible sulfur (TRS) emissions that are part of the characteristic odors of the Kraft process. Consequently, competitive solvent-based pulping processes were developed to minimize or eliminate TRS emissions, notably: 1) Organosolv (Methanol-based) patented 1971, first mill in Kelheim, Germany (1992); 2) Alcell (Ethanol-based) Newcastle, Canada (1989); and 3) Alkaline Sulfite Anthraquinone Methanol (ASAM) pilot plant in Heidelberg, Germany (Mid-1980's). Interestingly, as of today, all of the above failed whereas sulfite (1874) and Kraft (1890) processes are still in use! Other processes are under development, e.g. ionic liquids (ILs)/deep eutectic solvent (DESs) and acknowledged as promising (CEPI 2014), but still far from being implemented in industry.

The 2018 Intergovernmental Panel on Climate Change (IPCC), a meta study co-written by more than 130 authors synthesizing over 6,000 scientific references reported that human activities have caused approximately 1°C of global warming since the Industrial Revolution; this warming will likely reach 1.5°C between 2030 and 2050 if current activities continue. Since 2009, for Canada only, the costs of catastrophic events related to climate change is exceeding one billion dollars a year and is significantly increasing worldwide. The context requires that we act sustainably, and act now.

A Call for In-depth Transformation through Efficient and Focused Innovation

For the last two decades, the pulp and paper industry has been facing major challenges and most agree that a radical transformation is needed. This transformation should be aligned, more than ever, with fundamental trends such as world population growth and the increasing use of the virtual world (internet, cloud computing and storage, e-books, etc.). By 2050, the world population is expected to grow to more than 9 billion people, with nearly 70% living in urban areas, enhancing the complexity of problems such as waste management (OECD 2012). This calls for innovation based upon "the 12 Principles of Green Chemistry", focusing on the production of renewable materials and branching into unexplored markets and innovative applications. One of the promising solutions is Biorefinery.

Why Biorefinery? This competitive technological platform from Kraft process integrates biomass conversion to produce fuels, power, heat, and value-added chemicals and biomaterials.

Biorefinery isn't new, and it is worth mentioning a few noticeable examples of innovations derived from it; i) Borregaard: Now +200 lignin derivatives, 1st investigation (1909), 1st mill USA (1934); 2nd mill Norway (1967); ii) CelluForce: NCCTM Canada (Q4-2011); iii) API's AVAP pilot plant in Thomaston, USA: fuel and/or chemicals (Q1-2013); iv) Domtar: LignoBoost / Bio-Choice (Q2-2013); v) FPInnovations: Cellulose Filaments (CF) (Q4-2013); vi) UPM, Finland, 2nd generation bio-diesel (2014); vii) Stora Enso, LignoBoost, Finland: (2015); and viii) West Fraser, LignoForce, FPInnovations, Canada, (2016).

Building our collective future through collaboration and partnership

The capacity to transform our industry in a viable manner resides on effective collaboration with the scientific community, producers, suppliers, stake holders and end users. In addition, an agile synergy of the Trifecta, resulting from the discoveries by Academia, strategic support through Government, and innovation capacity and willingness of the Industry, is key in achieving our transformational goals.

Based on the example of the resilience of the Kraft pulping process, innovations within the Pulp and Paper Industry must be implemented in a sustainable way to preserve ecosystems and improve human health, hence making sure that both the Homo Sapiens species, and the Trees of Life, continue to co-exist.

Thanks to Mrs Sylvie Gelinas from Noos Technologie for valuable editing.

Dr. ROGER GAUDREAULT Invited Researcher,
University of Montreal This email address is being protected from spambots. You need JavaScript enabled to view it.

The 2016 Canadian Green Chemistry and Engineering Award, sponsored by Green Centre Canada, was awarded to Dr. Roger Gaudreault for his significant contribution to Green Chemistry research and development through 30 years of dedicated work for the Pulp and Paper Industry, industrial water treatment and renewable energy.

Dr. Gaudreault's expertise notably spearheaded him to develop an integrated innovation Green Chemistry approach based on recycled fibres. His scientific and applied background helped developed strong partnerships between academia and industry. He has been a member of the Centre in Green Chemistry and Catalysis (CGCC) since 2011 and associate member of the Quebec Centre for Advanced Materials (QCAM) since 2018. Dr. Gaudreault's scientific interests include; green chemistry, neuroscience, kinetics of colloids, chemistry of pulping/bleaching and papermaking, recycling, corrosion inhibition, biomaterials and biofuels from wood biomass, and molecular modelling. Dr. Gaudreault did a Post-Doctoral Fellowship co-supervised by Professors David A. Weitz from Harvard University and Theo van de Ven from McGill University (2005-2006). He completed a PhD on molecular modelling from McGill University (2003); MSc. in Pulp and Paper from Université du Québec à Trois-Rivières (1991); and a BSc in Chemistry from Université du Québec à Chicoutimi (1986).

Dr. Gaudreault has also been named PAPTAC Fellow 2017 in recognition of his outstanding long-term and significant contribution to the Association, the pulp & paper and forest products industry and for the advancement of science and technology in the industry.