Juha Lehtonen

Title : Catalysis for biomass conversion to traffic fuel compounds

Abstract:

Lignocellulosic biomass is the most abundant raw material to produce sustainable advanced traffic fuels. However, conversion of solid biomass to high quality liquid fuels has turned out to be challenging due to heterogeneous nature of biomass. Lignocellulosic biomass can be converted into liquid fuels by applying thermochemical methods such as gasification or fast pyrolysis and by further upgrading the intermediates. Alternatively, biomass can be fractionated and the constituents (cellulose, hemicellulose, lignin) can be upgraded separately to liquid fuels by chemical or biochemical conversion. In all of these routes, except in the biochemical conversion, heterogeneous catalysis is in key role. In gasification route, efficient catalysts are needed for gas cleaning and synthesis gas upgrading to liquid products. Heterogeneous acid catalyst can be applied for fast pyrolysis (catalytic fast pyrolysis) to improve the properties of bio oil or they can be used for bio oil upgrading either to remove the oxygen by hydrodeoxygenation (HDO) or to crack the bio oil by acidic zeolites e.g. in oil refinery FCC units.

Both sugar fractions (cellulose and hemicellulose) and lignin can be upgraded by heterogeneous catalysts. Sugars can be converted to HMF (celluilose) or furfural (hemicellulose) by heterogeneous acid catalysts and further upgraded to dimetylfuran (DMF) and 2-methylfuran (DMF) by catalytic hydrotreatment using advanced metal catalysts, respectively. Both, 2-MF and DMF are promising new bio-based gasoline components with good fuel properties.

Lignin is a challenging raw material for the upgrading due to it’s high reactivity. On the other hand, it is an attractive source of aromatic hydrocarbons to be used for the applications where aromatics are needed such as jet fuels. Lignin can be depolymerized by solvolysis or hydrogenolysis where many different supported metal catalysts have been studied. In solvolysis, liquid hydrogen donors such as ethanol are used whereas in hydrogenolysis, molecular hydrogen is provided to the reactor. The main role of hydrogen is to prevent undesired re-condensation reactions and the depolymerization mainly takes place by thermal or catalytic cracking. Another strategy to depolymerize lignin is to apply fast or catalytic fast pyrolysis. In both cases, depolymerized lignin can be further upgraded by hydrodeoxygenation to remove remaining oxygen.

Biography:

Juha Lehtonen (Dr. Tech. in Chemical Engineering) is a Research Professor of Bioenergy and Thermochemical Processes at VTT Technical Research Centre of Finland. His research is focusing on catalytic and thermochemical conversion of biomass and carbon dioxide, heterogeneous catalysis, reaction engineering and renewable fuels and chemicals. He is an author or co-author of over 70 peer-reviewed publications. He obtained his doctoral degree (chemical reaction engineering) at Åbo Akademi University, Finland. His thesis was awarded as a best doctoral thesis in the field of chemical engineering in 1996 - 1997 in Finland. He has a long career in industrial research organizations as a specialist of chemical reaction engineering, catalysis and development of biofuels processes. He has also experience of many managerial positions in industrial R&D organizations. Before moving to VTT, prof. Lehtonen worked at Aalto University, Finland as a professor of Industrial Chemistry.