Biomasspyrolysisrefinery: Hydrodeoxygenation of Liquid Phase Pyrolysis Oil

BiomassPyrolysisRefinery: Hydrodeoxygenation of Liquid Phase Pyrolysis Oil H. Pucher , R. Feiner , N. Schwaiger , P. Pucher* , M. Siebenhofer Graz University of Technology , Institute of Chemical Engineering and Environmental Technology , *BDI-BioEnergy International AG Non-renewable energy resources such as oil and coal will not suffice the increasing demand of energy in the future. It is assumed that renewable resources such as biomass are able to fill this dawning gap because they have been considered as the most promising energy sources in the next century [1]. In addition the European Commission has released a directive to increase the volume of renewable biofuels for transportation to 10% by 2020 [2]. To fill the upcoming gap and meet the requirements of the directive a biomass liquefaction concept from renewable resources has been developed. The BiomassPyrolysisRefinery concept consists of two main process steps. In the first step lignocellulosic biomass like wood and straw , is converted in pyrolysis oil and pyrolysis char through liquid phase pyrolysis. In the second step these intermediate products are upgraded. Two promising upgrading technologies were investigated: hydrodeoxygenation [3] [4] of pyrolysis oil , and hydrogenation of liquid phase pyrolysis char. The main focus of this project was to investigate and optimize upgrading of liquid phase pyrolysis oil to maximize the output of the carbon rich fraction , raise stability and identify potential fields of application. Investigations were carried out in lab size batch mode. Through hydrodeoxygenation the polar , highly acidic , water and oxygen rich liquid phase pyrolysis oil is converted into an appropriate , carbon rich , oxygen poor and water poor product phase. The upgraded product is seemingly ready for further processing in conventional oil refining. Depending on the field of application , the liquid phase pyrolysis oil can be dehydrated and the water content can be reduced by 90%. The operation parameters for hydrodeoxygenation , like hydrogen pressure , temperature , reaction time and catalysts , were determined. Table 1 shows representative results. Table 1: Comparison of Liquid Phase Pyrolysis Oil , Pyrolysis Oil dehydrated and Pyrolysis Oil upgraded.     Liquid Phase Pyrolysis Oil Pyrolysis Oil dehydrated Pyrolysis Oil upgraded Water Content [%] 60 7 4 Lower Calorific Value [kJ/kg] 7600 20500 30160 Carbon Content [%] 22 52 69 Hydrogen Content [%] 10 7 9 Oxygen Content [%] 68 41 21 Nitrogen Content [%] <1 <1 <1 70 percent of the organic carbon of the liquid phase pyrolysis oil was transferred to a carbon rich product phase (upgraded pyrolysis oil). The upgraded pyrolysis oil has an oxygen content of about 21% and a hydrogen content of about 9%. In conclusion trough dehydration as well as hydrodeoxygenation a dehydrated/upgraded pyrolysis oil with lower oxygen and water content but higher energy density is produced. Composition and characterization of the products were determined by SEC , GC-MS , elemental analysis , Karl Fischer Titration , TAN , NDIR continuous gas analysis and by a solvent-solvent extraction according to the Oasmaa guideline [6]. [1] Wang , G. et al. , "The direct liquefaction of sawdust in tetralin ," Energy Sources , Part A , pp. 1221-1231 , 2007. [2] Richtlinie_2009/28/EG , "EU Richtlinie zur Förderung der Nutzung von Energie aus erneuerbaren Quellen und zur Änderung und anschließenden Aufhebung der Richtlinien.". [3] Mercader , F.M. et al. , "Hydrodeoxygenation of pyrolysis oil fractions: Process understanding and quality assessment through co-processing in refinery units ," Energy & Environmental Science , pp. 985-997 , 2011. [4] Wildschut , J. et al. , "Insights in the hydrotreatment of fast pyrolysis oil using a ruthenium on carbon catalyst ," Energy Environ. Sci. , pp. 962-970 , 2010. [5] Mortensen , P.M. et al. , "A Review of catalytic upgrading of bio-oil to engine fuels ," Applied Catalysis A: General , pp. 1-19 , 2011. [6] Anja , O. , Fuel Oil Quality Properties of wood-based Pyrolysis Liquids , 2003.