Laurel Brunner’s Verdigris Blog: Paper Tigers Hear them Roar

The paper industry has often been the target of chippy greens looking to offload their eco-anger. If past practise is anything to go by, they have some justification, but it is time to start cutting paper companies a lot more slack. Pulp and paper manufacturers have made massive improvements to their environmental footprint over the last few years, not least substantial reductions in energy usage and waste. The Confederation of European Paper Industries (CEPI), is now taking steps to improve it even more.

The CEPI Two Team competition was set up to identify potential technologies that would help CEPI fulfill the requirements of its 2050 Roadmap. This requires an 80% reduction in fossil based CO2 emissions by 2050. In the words of Teresa Prensa, CEPI’s director general, the goal is to: “change the way we operate, reduce costs, revolutionize technology, add value and lower our energy consumption and carbon emissions”. The Two Team competition produced eight finalists and one clear winner, a biochemical technology that could replace current methods of pulp production.

Paper pulp is produced either mechanically by grinding wood chips into mush to separate the raw fibres from the lignin which binds them together, or chemically. This involves stewing the wood chips with various chemicals and is generally more expensive. The resulting pulp is however strong with good brightness and can be used in combination with some mechanical pulp, for instance to produce lightweight publication stocks. Both methods involve a lot of energy and water: the World Resources Institute estimates that pulp and paper production produces 500 million tonnes of CO2 per year.

CEPI’s Two Team winner involves neither mechanics nor chemicals, but instead uses the principles of biochemistry. The favoured solution is to use Deep Eutectic Solvents (DES), naturally occuring chemical compounds that can dissolve the lignin out of wood. Potentially, these solvents could make it possible to produce pulp at lower, more energy efficient temperatures for reduced emissions and waste volumes. DES are essentially designer solvents based on combinations of chemicals that work on any type of biomass, dissolving it into lignin, cellulose and hemicellulose (somewhere between cellulose and sugar).

These clever chemicals may also be able to recover cellulose from waste as well as melt ink residues in recovered paper, so they have potential use in deinking too. When combined with wood, DES separate the fibres producing pure lignin and cellulose as by-products. Biochemists can use both of these as raw materials for other chemical products. The DES method does away with the huge amounts of water and subsequent drying required to make paper. This is a massive source of energy savings. None of this is commercially viable yet, but it is an indication of how seriously the pulp and paper industries now take sustainability. It’s a matter of survival.