Kraft Lignin Depolymerization in Near-Critical Water: Effect of Changing Co-Solvent
Journal article, 2014

As part of developing a process to valorize lignin in a pulp mill with lignin separation, the depolymerisation of lignin to valuable chemicals was investigated in near-critical water. This was done by using methanol as co-solvent and hydrogen donor, phenol to suppress repolymerization (e.g. formation of char), and ZrO2 as a heterogeneous catalyst, with potassium carbonate as a co-catalyst. The reaction was carried out in a continuous flow fixed-bed reactor (500 cm(3)), at 280-350 degrees C and 25MPa. An important aspect is to suppress char formation. Therefore, the char formation was studied by using different concentrations of methanol and phenol. The char yield varied between 14% and 26%. When using methanol as the only co-solvent, the char yield decreased with increasing methanol concentration. Adding phenol resulted in a further decrease. The reactor outlet consisted mainly of two liquid phases, an aqueous and an oil phase, mixed together. The chemical analysis of the aqueous phase showed the presence of mainly phenolic compounds, for instance guaiacol, catechol, phenol and cresol.

hydrogen donors

phenolic compound

lignin conversion

LignoBoost

near-critical water

char formation

Author

Tallal Belkheiri

Industrial Energy Systems and Technologies

Lennart Vamling

Industrial Energy Systems and Technologies

Huyen Nguyen Lyckeskog

Chalmers, Chemical and Biological Engineering, Forest Products and Chemical Engineering

Marco Maschietti

Chalmers, Chemical and Biological Engineering, Forest Products and Chemical Engineering

L. Olausson

Valmet

Sven-Ingvar Andersson

Chalmers, Chemical and Biological Engineering, Applied Surface Chemistry

Lars-Erik Åmand

Industrial Energy Systems and Technologies

Hans Theliander

Wallenberg Wood Science Center (WWSC)

Chalmers, Chemical and Biological Engineering, Forest Products and Chemical Engineering

Cellulose Chemistry and Technology

0576-9787 (ISSN)

Vol. 48 9-10 813-818

Subject Categories

Paper, Pulp and Fiber Technology

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Latest update

8/24/2018