Metsä Group’s pilot plant produces eco-friendly textile fibre out of paper pulp

A textile fibre pilot plant owned by Metsä Group and the Japanese company Itochu was completed next to the Äänekoski bioproduct mill at the start of the year. Sweco’s experts in industry, building service systems and structural engineering worked as consultant partners in this unique project.

A pioneer in forestry and bioeconomy, Metsä Group has already developed new textile fibre manufacturing technology for several years in collaboration with different research institutes. “The first large-scale co-research project FuBio began in 2009 with new chemicals that dissolve pulp as one research focus,” explains Metsä Spring CEO Niklas von Weymarn.

In 2012, Metsä Group established its own comprehensive research project and began cooperation with Itochu two years later. Itochu and Metsä Group’s innovation company Metsä Spring together own MI Demo that is in charge of developing the pilot plant of about EUR 40 million.

“However, the pilot plant is only an intermediate step or, in the best case scenario, a stepping stone towards gaining answers to critical questions,” von Weymarn says. The long-term objective is a full-scale production plant in Äänekoski, for example, and later in connection with other Metsä Group pulp mills. “If all goes to plan, we will have the potential to further develop the technology and commence the commercial production of the textile fibre in due course.”

Confidential relationship with the client

There are several ongoing textile fibre projects in Finland, but no other pilot plant of the same scale. The pilot plant, about 120 metres in length, receives its raw material from the nearby Äänekoski bioproduct mill that was completed on schedule in late summer 2018.

“We were in charge of the principal design of the bioproduct mill, meaning that we already had a direct and uncomplicated cooperation with Metsä Group,” explains Project Manager Leena Hannonen from Sweco. Mutual trust was an important factor in the preliminary design and implementation planning of the pilot plant. “For example, we participated in the procurement negotiations and document drafting in confidence.”

Expertise required in equipment acquisition

Sweco worked in close cooperation with the project’s equipment suppliers from several different countries. The manufacturing method is unique and the plant required equipment of just the right size.

“The amount of material required by the pilot plant corresponds to only a couple of minutes of the bioproduct mill’s production, meaning that it was difficult to find suitable equipment for such small flow amounts,” says Hannonen. The same equipment types are to be used later in the full-scale production plant. “Careful investigation allowed us to find new equipment suppliers, and traditional suppliers in the field provided us with their pilot equipment.”

Another challenge was the unique solvent that was not initially available anywhere in the world in the required amount. The upscaling of solvent production was carried out alongside the pilot plant project. “Sweco helped us ensure that it was safe to work with the new solvent at the plant. Occupational safety is our priority,” von Weymarn emphasises.

“Our chemical safety specialists produced different surveys and risk analyses and ensured that the equipment suppliers produced the required documentation for CE markings,” Hannonen adds.

Pilot plant saves water and energy

The pilot plant reached the implementation stage in early 2020. The new manufacturing technology helps reduce the global environmental issues related to cotton production due to the significantly lower water consumption, for example.

“According to the lifecycle analysis performed by an external consultant, the pilot plant’s carbon footprint, i.e. global warming potential, is significantly smaller than in cotton production,” von Weymarn says.

Instead of dissolving pulp, the process utilises undried paper pulp. “The recovery of textile fibre is greater, the manufacturing process is cheaper and there is less need for chemicals,” Hannonen explains. Also, one processing stage is eliminated, which saves energy. “The undried pulp is normally dried into sheets at the bioproduct mill, but the raw material is now extracted for textile fibre manufacturing before drying.”

The pilot plant receives all of its energy and raw material from the bioproduct mill that is the first fossil-free facility of its kind in the world. “Thanks to the bioproduct mill, the pilot plant is also fossil-free,” von Weymarn emphasises.