Simple lignin conversion to marine diesel.

Lignin from biorefineries is an underutilized resource that is typically burned as a low value solid fuel. Transformation of solid lignin to a liquid fuel will pose a significant added value and improve the economy of biorefineries. The lignin from biorefineries is a low sulfur feedstock contrary to the majority of pulp and paper lignin, thus biorefinery lignin is an ideal candidate for production of a low sulfur liquid fuel. The maritime shipping industry is of particular interest due to increased legislative demands for sulfur free fuels. Also, fuel standards may be satisfied with a bio-crude as the engine operation allows for the combustion of crude oil products.

We designed a simple one-pot process where biorefinery lignin residue is cooked in bio ethanol at 300 – 400 °C which allows for easy implementation in existing biorefineries. The process does not require the use of a catalyst or the use of hydrogen as a lignin-oil with an oxygen content of <10 wt% is obtained, which allows near complete solubility in marine diesel. The oil is ash and sulfur free and contrary to pyrolysis oil also water free, non-corrosive and stable.  A main mechanism in the liquefaction of the lignin is believed to be quenching of the thermo radicals thus preventing condensation reactions. Oil yields up to 90 % have been achieved and interestingly a higher lignin loading also yields a higher quality oil product. The presentation will also discuss further development and optimization of the process.