Looking inside the box: Improving the sustainability of pulp mills

Although the pulp and paper industries are among the top performing manufacturers when it comes to sustainability, there is still more that can be done to lower carbon footprint. According to the International Energy Agency (IEA), the pulp and paper sector was responsible for just under 2% of all emissions from industry in 2022.

Michael Bergmann, ANDRITZ Director of Digitization and Automation, Pulp Drying, says, “This estimation of emissions from the IEA confirms clearly that there is more work to be done at pulp and paper mills to reduce emissions even further. It is common knowledge in the pulp industry that a major part of the energy consumption associated with its production comes from the drying process.”

As part of its program to search for new solutions for improving sustainability at pulp mills, ANDRITZ recently employed the creative skills of a team of young students from the TU Graz who were put to the test on reducing the CO₂ footprint of the pulp drying process.

“We have a constant, ongoing program at ANDRITZ to improve and optimize the sustainability of our technology. As part of this program, we decided to create an internal project in association with the TU Graz, to see what new ideas would emerge from a student team when it came to the pulp drying process,” explains Bergmann.

BREAKING AWAY FROM THE NORM

The Institute of Innovation Management at TU Graz in Austria breaks away from the norm at universities and complements industrial operations by delivering a combination of traditional, high-quality education mixed with real, practical industry cases.

Professor Christian Ramsauer, Head of the institute in Graz, is himself a former CEO of a high-tech company and joined TU Graz in 2011. “When I joined the institute, it was to focus on teaching and stressing the importance of creative innovation in industry,” says Ramsauer. “Most importantly, I wanted to ensure that the technical university was a partner of industry so that students could benefit from the real-life challenges that are presented in all types of manufacturing.”

As part of this engagement with industry, the university introduced a dedicated, unique course inspired by the one-year program in Design Thinking offered by the Stanford University in California, USA. In the case of TU Graz, the course was named “Product Innovation” which is based on the concept of Experience Based Learning, giving students the opportunity to work on real-life tasks directly provided by industry partners, such as ANDRITZ.

AMAZING WHAT STUDENTS CAN DO

ANDRITZ management spotted the opportunity the institute offers with its Product Innovation course early on and has been a partner with the university several times over the last years. The collaboration involves ways to maximize the performance of its technology in its many different fields of industry.

Ramsauer said, “Austrian companies such as ANDRITZ have a real opportunity when they work with us by having access to very enthusiastic, well-educated students who are unencumbered with corporate rules or boundaries and can really think in a creative way on the solutions to challenges.

“We always find it amazing what students can do when they are working in diverse teams, from different backgrounds.”     

Marion Unegg, Project Leader of the Project Innovation courses has a background in environmental system sciences and economics, and is now in her fourth year as project leader at the university. Unegg says, “The latest challenge sent to us by ANDRITZ was to find ways to make the pulp drying process more energy efficient and contribute to making the pulp mill more circular when it comes to sustainability and carbon footprint reduction.”

THE CHALLENGE FROM ANDRITZ

After the team was formed and consolidated, the challenge posed to the Product Innovation team came direct from ANDRITZ. Sebastian Harringer, student Team Leader for the challenge, said, “The project concerned the reusing of energy in the drying area of a pulp mill. The specific challenge was to reuse two exhaust streams from the dryer in the most feasible way possible.”

As the task began, more details from ANDRITZ were included, as well as some overall restrictions and limitations. There was also a mill visit to a pulp mill near Graz. “The mill visit was the perfect place to begin,” says Harringer. “We were all very impressed with the size of the dryer, and of course with the pulp mill itself. We were very enthused by what we saw, and it helped greatly to come up with ideas for a solution.”

The whole project on the ANDRITZ challenge took place over a period of seven months with regular check points in between to monitor progress.

THE RESULTS: OVER 30% ADDITIONAL HEAT RECOVERY AND CO₂ REDUCTION

After presenting several ideas to ANDRITZ, one solution was finally selected as being the most viable option, and it was presented at the Innovation Gala in the summer of 2023. The result of a Product Innovation challenge is generally in the form of a prototype, however, in this case, the student team came up with a way to redimension the heat recovery of the dryer in a pulp mill, and showing the benefits that can be achieved. Harringer explains, “In our case we didn’t have a physical prototype, however we focused on presenting the innovation we came up with as a simulation and what can be achieved by rearranging the facilities using data to back it up.

“Roughly, with our solution applied to the dryer exhaust configuration, we found we can recover about 32% of additional heat and we reduced the carbon footprint of the dryer by a similar amount. The feasible solution involved adding an additional heat pump and heat exchanger and made efforts to reduce the waste of energy by reusing the heat and making the mill more circular.”

Harringer adds: “When it comes to investment and economics, we calculated that the ROI of this innovation would be around four years, which in the case of a new pulp mill with a lifetime of 50-60 years represents a very good investment.” 

Johan Niklasson, Senior Development and Technology Engineer, ANDRITZ Pulp Drying, says, “We really did see some innovative ideas emerging from the student team. A lot of them we had never even considered, so it was a very valuable project from our side. Of the ones that we thought of as most viable, we will be looking more deeply into them, and depending on our strategy, we could well see some of the ideas being put into place in the future.”  

Bergmann concludes, “We have ambitious goals in front of us to reduce carbon footprint and this project with TU Graz was an important and interesting cornerstone of this journey.  We certainly achieved very interesting results with the team, but we also discovered ideas that wouldn’t work, which is also a very important part of the journey.”

“The final idea we chose looks very promising both in terms of sustainability and also in economics. I am happy and proud of the team from TU Graz and ANDRITZ for coming up with this solution.”