1. Context

The paper industry has been producing cellulose fibers for over a hundred years, using a process that can best be described as a biorefinery. They use a renewable raw material (wood), often from sustainably managed forests, and their supply logistics have been in place for a long time. They produce a material (pulp or cellulose), chemicals (from wood extractives) and energy.

This biorefinery could be improved by further valorizing the various constituents of wood. This is what is done in plants using the acid bisulphite process, the plant that has taken the biorefinery concept the furthest being the Borregaard plant in Sarpsborg, Norway: This plant produces, among other things, high-purity cellulose for cellulose ether and ester applications, lignosulfonates, second-generation ethanol from black liquor fermentation, and vanillin from lignosulfonates.