Scientific collaboration is deeply rooted within Lenzing’s R&D. In view of the major challenges (like climate change) and ever more complex topics, such cooperation is needed, which is why Lenzing is intensifying its activities in this field. The collaborations range from large research centers to small individual projects and also include important networking with the scientific community.
One of the largest research collaborations is with the Austrian Wood K plus competence center. Wood K plus is a leading research institute for wood and wood-related renewable resources in Europe. Lenzing is its largest industrial partner. Recent topics addressed by the competence center include advanced biomass utilization, lignin and hemicellulose utilization, or the use of enzymes in the production process.
Lenzing is also a partner in the Christian Doppler Laboratory for an efficient, recycling-based circular economy lead by the Technical University Vienna. The laboratory aims to provide the scientific knowledge base for efficiently recovering secondary raw materials from different municipal solid waste streams. Another cooperative research project dealing with circular economy, more specifically textile recycling, is the recently started EnzATex project.
Bilateral research is also important to Lenzing’s approach to scientific collaboration. Noteworthy examples include its collaboration with the Scripps Institution of Oceanography, University of California San Diego, USA, on the biodegradability of cellulose-based materials in the maritime environment or its collaboration with the Linz Institute of Organic Solar Cells (LIOS), Johannes Kepler University Linz, on the dielectric properties of cellulose fibers.
Lenzing is also active in scientific networks such as the European Polysaccharide Network of Excellence (EPNOE) and in supporting research projects by giving input and engaging in discussions. Finally, experts from Lenzing R&D also participate in relevant conferences and gave more than ten talks in 2021 – most of them with a strong focus on sustainability.
Alternative sources of raw materials for fiber production
Any plant-based material can potentially serve as a source of cellulose and hence as dissolving pulp for fiber production. Lenzing has undertaken extensive research into many different alternative non-wood cellulose sources. In its research, Lenzing identifies promising new cellulose sources and carefully considers their availability, technical feasibility, and economic scalability as well as the overall ecological impact with respect to Lenzing’s climate target and circularity approach.
Studies have been conducted on sources such as annual plants like hemp, straw, and bamboo. In general, annual plants have a higher growth rate per hectare than trees. Additionally, certain species have a higher cellulose content. Some of them are already available in large quantities, especially in the form of agricultural waste. This allows an attractive cellulose yield per hectare to be achieved; however, the feasibility of any alternative raw material needs to be assessed case by case.
Based on current data, large-scale and sustainable production of cellulose is still best conducted using wood from sustainably managed forests instead of the above mentioned alternatives.
At the moment the most promising alternative raw materials to wood are residuals from textile production and used clothing. Here Lenzing came up with the first industrially implemented solution: REFIBRA™ technology, which uses a large amount of textile waste as feedstock and represents an important step towards achieving a circular economy.
In order to progress faster and deliver relevant volumes to the market Södra and Lenzing have teamed up in the field of textile recycling in 2021. Together they are now developing their respective processes with the goal of a recycling plant with a capacity of 25,000 tons in 2025. For more information, please see chapter “Circularity & resources”.
At the same time, as an innovation leader it is Lenzing’s aspiration to find new solutions, looking beyond the horizon. One example is the already mentioned cooperation with Orange Fiber, where it was possible at pilot scale to substitute 20 percent of wood pulp with pulp derived from orange residues. Lenzing is also an active partner in the newly founded INGRAIN innovation alliance, which deals with a biobased circular economy with the goal of connecting agriculture, food processing, and the textile industry.
In order to develop further new sources of non-wood-based cellulose in the future, it requires targeted research into the ecological and economic aspects of industrial production, as well as increased cooperation. A number of challenges need to be addressed, which are described in more detail below.
Alternatives such as bamboo, straw, and various annual plants do not yet meet Lenzing’s needs in terms of availability in the required quality and amount. Many sources from annual plants are only available in the harvesting season and are difficult to store for year-round use. Annual plants are thus especially suitable for seasonal production campaigns. Despite specific benefits and high annual growth per hectare, the material is very bulky and more costly to transport. This favors obtaining the raw materials locally and keeping production capacities small.
The conversion of forest to agricultural land for annual plants is a worldwide phenomenon that increases the pressure on all kinds of forests. Its drawbacks can be seen with palm oil production, for example. As sustainably managed forests store much more carbon per hectare than annual crops, this trend adversely affects the CO2 balance of the entire value chain. Therefore, the carbon balance must be thoroughly calculated while including all co-products from annual plants.
Another important factor in the sustainability performance of annual plants is the management of the agricultural areas. Highly productive sites need far more fertilizers and pesticides than forests, causing other environmental issues. For example, the overall environmental profile of large-scale bamboo plantations is known to be unsatisfactory.
When looking into processing, important factors with regard to the environmental impact include energy consumption and the use of process chemicals in pulp production. They depend heavily on the actual process and vary significantly from one annual plant to the next. For instance, dissolving pulp can be made with cotton linters, as practiced by the viscose industry in some regions. However, the pulping process uses substantial amounts of chemicals and energy. If cotton linter pulp facilities are not state-of-the-art, resource use, emissions, and waste could be higher for cotton linter pulp.
Apart from not causing additional environmental issues, fibers produced with alternative feedstock must meet the same quality criteria as wood-based fibers. The biorefinery process for wood-based fibers is closely aligned with the raw material. This keeps quality and efficiency high and yields climate-neutral bioenergy as a co-product. With non-wood feedstocks, less bioenergy may be generated as a co-product, requiring additional energy sources for processing the feedstock into dissolving pulp, resulting in a potentially negative environmental impact.
Annual plants contain more mineral components and organic substances that have to be removed to produce high-quality dissolving pulp. This purification typically requires the use of aggressive chemicals and causes waste issues. It is a big challenge to develop new sustainable technologies for these materials while maintaining product quality and ecological friendliness. By contrast, in woody plants like trees, these components are concentrated in the bark, which can be easily removed in the first stage of the process.
Paper industry experience of these sources is of limited use since dissolving pulp has to meet very different quality and purity requirements. While modern breeding and harvesting concepts have been developed, a new biorefinery process for annual plants still has to be adapted to the special requirements, not to mention circulation management for process chemicals and treatment of impurities originating from the plants. So far, no established industrial process meets these prerequisites.
For more information, please see the “Wood and Pulp” focus paper.