Complete utilisation of biomass in alkaline oxidation (AlkOx) biorefinery

Hanna Hörhammer (Corresponding author), Matti Siika-aho, Jari Sirviö

Research output: Contribution to conferenceConference AbstractScientific


With climate change and material shortage, efficient usage of resources is very crucial in current and future biomass processing. Biorefineries generally aim at converting all parts of the biomass material into bioproducts, also efficiently utilising side and waste streams. Each biorefinery has specific characteristics depending on input material, processes and products. An AlkOx biorefinery is based on an alkaline oxidation process. Due to the usage of oxygen and the alkaline oxidation reaction, the AlkOx products have unique characteristics that have high potential for certain applications.
VTT has developed a two-stage AlkOx process for efficient fractionation of lignocellulosic biomass. The method relies on two cooking stages. The first stage is to extract the main part of the hemicelluloses, and the second stage is to delignify the remaining fraction applying Na2CO3 and O2. The AlkOx process can be applied on different types of biomass i.e. hardwood, softwood, waste wood and agro residues. The process conditions can be adjusted based on the raw material and the desired characteristics of the fractions produced.
The AlkOx process provides a cellulose rich fibre fraction and cooking liquors. The liquor from the 1st stage contains hemicellulose-derived compounds, whereas the 2nd stage liquor contains sulphur free lignin. The fibre fraction can be used either for sugar production and further to fermentation, or then through dissolving pulp to textile fibre production. Cellulose nanofibre (CNF) films could also be an alternative application for the fibre fraction. The hemicelluloses could be further processed for cosmetics or food applications, or converted to C5 sugars and further to platform chemicals. The oxidised sulphur free lignin has unique characteristics, and could be separated from the cooking liquor in order to be utilised e.g. as metal chelating agents, concrete plasticisers or dispersants for paints and coatings.
The chemistry in the AlkOx biorefinery is simple and the process is sulphur free. The AlkOx biorefinery could be a large stand-alone production plant, a smaller plant integrated to a kraft pulp mill, or a small stand-alone plant with novel chemical recovery solution. The energy and recovery aspects of the AlkOx biorefinery still need to be evaluated in more detail. The AlkOx biorefinery shows high potential for complete utilization of biomass. High yields of multiple high-value products offer avenues for feasibility and profitability of the AlkOx biorefinery.
Original languageEnglish
Publication statusPublished - 14 Oct 2020
MoE publication typeNot Eligible
Event9th Nordic Wood Biorefinery Conference 2020 - Virtual, Stockholm, Sweden
Duration: 13 Oct 202015 Oct 2020
Conference number: 9


Conference9th Nordic Wood Biorefinery Conference 2020
Abbreviated titleNWBC 2020
Internet address


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