HiFib: Innovative Fibre Technology for Sustainable Papermaking

Transforming agricultural food byproducts into a sustainable, high-quality source of pulp for papermaking

In the UK, paper is manufactured primarily from pulp obtained from recycled paper. Increased demand for paper in recent years – caused partly by the move away from plastic packaging materials – now means there is insufficient recovered paper to meet the paper industry’s needs, with an estimated shortfall of around 4m tonnes per year.

At the same time, there is growing commercial demand for stronger, lighter paper, which reduces transport costs and carbon emissions. However, fibre length deteriorates each time paper is recycled, so virgin wood pulp is often added to increase strength.

To address this multi-faceted challenge, the HiFib project explored how agricultural food byproducts could be turned into a high-quality source of pulp for papermaking. Supported by the Transforming Foundation Industries (TFI) challenge, a consortium of UK businesses and organisations investigated alternative sources of cellulosic fibres and how they could be processed to produce stronger, lighter paper and board. The consortium consisted of chemical manufacturers Axchem International and Renaissance Chemicals, agri-food valorisation businesses AgriFoodX Limited and Biopower Technologies, alongside packaging company DS Smith and the Paper Industry Technical Association.

“While there are existing processes that add strength to fibres, they are expensive and can impede the manufacturing process,” explained Professor Graham Bonwick, Director of AgriFoodX Limited. “We wanted to find a solution that exploited agricultural byproducts that would otherwise be incinerated or sent to landfill and could be produced economically, sustainably and in a way that’s compatible with existing manufacturing processes.”

Readily available fibre sources were evaluated, including brewers’ spent grain, apple pomace from juice and cider production and sugar beet. The project team also explored the technology and processes required to turn the byproducts into valuable pulp feedstock.

“Ultrasonication is a process that uses sound waves to disrupt a material. It’s effective and scalable but highly energy-intensive. The project team developed a mechanical process that was equally effective at modifying fibres but consumed less energy and was more compatible with existing manufacturing processes. We also investigated the use of different enzyme combinations to pre-process fibres to reduce further the amount of energy required,” says Professor Bonwick.

A pilot-scale plant for integration into an existing paper manufacturing facility was developed and evaluated. “We tested at 1-tonne quantities and demonstrated the technology could be scaled for commercial quantities,” says Professor Bonwick. “Importantly, the evaluation revealed the paper we were able to produce was much stronger than that made solely with recovered paper pulp. We estimate it could be used to make packaging that is 20% lighter, which represents significant savings in transport-associated energy costs and associated carbon footprint reduction.”

In addition to providing an opportunity to meet the demand for sustainable packaging, the technology has potential benefits for other industries. “We have started to explore blending fibres with polymers to produce composite materials. These have a range of potential applications in construction, automotive and aviation. We’re particularly interested in exploring their use in wind turbine blades – providing a more sustainable solution to a product that is currently very difficult to recycle,” says Professor Bonwick. “The innovations developed in this project will help the UK’s transition towards a circular bioeconomy.”