To achieve the climate goals, we must also replace fossil plastics and chemicals with bio-based products. A large proportion of the more valuable plastics and chemical products today contain aromatic structures, ie they have a large proportion of structures containing benzene rings consisting of very stable hexagonal rings of carbon. In nature, such structures are found in the lignin fraction in all plants. It is found in trees, stems, in seed shells, etc. There is a lot of lignin on the planet. In fact, lignin is the second most abundant natural polymer (long chain molecule) in the world after cellulose. The natural choice of raw material for making bio-aromatics will therefore be lignin, since this plant fraction already contains the structures we are looking for. The challenge is that lignin is quite stable and difficult to dissolve. When the cellulose industry makes cellulose for paper and chemicals, the tough part of the process is to dissolve and remove the lignin. However, it is only partially decomposed, and not as far down as aromatics that can be used to replace aromatics from oil. We can, of course, attach the molecule with more energy, as in pyrolysis at several hundred degrees under pressure. Then the aromatics are also destroyed and cause so many side reactions that the product is of little use. When lignin is broken down, many reactive components are created that tend to react with each other. This is what should be avoided. There are no industrial processes that give high enough yields and that are attractive today. In this project, we set ourselves ambitious goals of developing at least one process that can be industrialized. Due to the uncertainty of which process will work best, we focus on testing 3 different processes in parallel. If more than one process can be industrialized, it's just a bonus. Furthermore, we will invest resources in developing analytical methods, separation methods and applications for the bio-aromatics.
This project will address the challenge of developing one or several industrial technologies for conversion of the lignin fraction of lignocellulosic biomass to valuable bio-aromatic chemicals. Lignin constitute typically 1/3 of the lignocellulosic biomass, and no industrial technology to date is able to convert this to bio-aromatics with sufficient yields and in an economic way. A possible strategy would be to aim for production of a limited number of blends and a few pure compounds, a typical biorefinery mind-set, instead of only one single pure compound.
L2BA will focus on development of 3 oxidative depolymerization processes: aqueous oxidative depolymerization without catalyst (BOR) or with catalyst (LTH), and electrochemical degradation (JGU). Application areas in focus will be bio-based polymer foams and additives, bio-based epoxy resins and PUR, organic electrolytes and bio-based performance chemicals. L2BA will focus on creating valuable low molecular weight (MW) aromatic products from lignosulfonates which are produced from sulphite pulping and from sulphite pretreatment processes like Borregaard’s BALI process. Lignosulfonates are water soluble polyanionic lignins. Water soluble lignins have a substantial advantage, since the processing can commence in water, no organic solvents needed, no explosion risk and no need for expensive regeneration of solvents.