5264 r2010 American Chemical Society pubs.acs.org/EF Energy Fuels 2010, 24, 5264–5272 : DOI:10.1021/ef100573q Published on Web 09/01/2010 Characterization of Hydrotreated Fast Pyrolysis Liquids A. Oasmaa,* ,† E. Kuoppala, † A. Ardiyanti, ‡ R. H. Venderbosch, § and H. J. Heeres ‡ † VTT, Biologinkuja 3-5, Espoo, P.O. Box 1000, 02044 VTT, Finland, ‡ Rijks Universiteit Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands, and § BTG Biomass Technology Group B.V., Pantheon 12, 7521 PR Enschede, The Netherlands Received May 7, 2010. Revised Manuscript Received July 5, 2010 This paper focuses on analytical methods to determine the composition of hydrotreated fast pyrolysis liquids. With this information, it is possible to gain insights in the chemical transformations taking place during catalytic hydrotreatment (hydrogenation and/or hydrodeoxygenation, HDO) of pyrolysis liquids. Three different samples, produced at different hydrotreatment severity levels (defined by temperature and residence time) using Ru/C as the catalyst, were analyzed in detail. The composition of the products was determined by solvent fractionation followed by detailed analysis of the various fractions by gas cheromatography/mass selective detector (GC/MSD), capillary electrophoresis (CE), and NMR ( 1 H NMR, 13 C NMR, and 31 P NMR). The decrease in the carbohydrate fraction was easily followed by the Brix method after solvent fractionation. Introduction The objective of catalytic upgrading of pyrolysis liquids is to improve their product properties and to extend the applica- tion range. For instance, the EU BIOCOUP project concerns the conversion of pyrolysis liquids into a product suitable for cofeeding in conventional oil refineries. 1 The difference in properties between highly polar pyrolysis liquid and a typical aliphatic fluid catalytic cracking (FCC) feed is significant and poses a real challenge. Oxygen in pyrolysis liquids is bound to various compounds in the liquid, 4 and full removal of oxygen would lead to very low product yields. Hence, the discovery of the lowest oxygen level of the product that still qualifies as an FCC feed is of utmost importance. In a recent paper, it was concluded that oils with oxygen contents as high as 17-28 wt % (dry basis) could be used for coprocessing in conventional FCC processing units (Mercader et al. 5 ). However, it is envisaged that not only the oxygen content alone but also the type of oxygen containing compounds determines the suitability of the product as a refinery feed. Catalytic hydrotreatment with heterogeneous catalysts at elevated temperatures (up to 500 °C) and pressures (up to 300 bar) has been identified as a very promising option to improve the properties of pyrolysis liquids and make them suitable as a refinery feed. Results from the BIOCOUP project on the hydroprocessing of pyrolysis liquids have been presented recently. 2 A two-stage hydrotreatment process, initially pro- posed by Elliott et al. 3 is employed. However, there is a need for detailed information on the chemical composition of these hydrotreated oils. With this information, the chemical trans- formations taking place during the hydrotreatment process can be monitored and may provide insights in desired chemi- cal transformations to improve properties and optimize the use of the product oils for cofeeding in refineries. The objective of this paper is to provide and discuss analytical methods suitable for the characterization of up- graded fast pyrolysis liquids. The focus is on providing analytical protocols to determine the composition of the products at a molecular level. The products are very complex in nature and contain hundreds of compounds belonging to a variety of organic compound classes. This poses a real chal- lenge. To reduce complexity, a solvent fractionation method was applied as the first step in the analytical protocol. This method (Figure 1) originally developed for crude fast pyro- lysis liquids 6 leads to a number of fractions with chemical components of similar solubility characteristics. It has been used successfully for the characterization of pyrolysis liquids and to determine changes in composition during storage. A shorter and faster method has been developed more recently. 7 We will show that solvent extraction in combination with other techniques ( 1 H-, 13 C-, 31 P NMR, gas chromatography/ mass selective detector (GC/MSD)) is a very useful approach to gain insights in the composition of upgraded pyrolysis liquids. *To whom correspondence should be addressed. E-mail: anja.oasmaa@ vtt.fi. (1) Solantausta, Y. BIOCOUP: renewable energy from forest indus- try to conventional refineries. Proceedings of the 2nd Nordic Wood Biorefinery Conference, NWBC-2009, Helsinki, Finland, September 2-4, 2009, pp 136-137. (2) Venderbosch, R. H.; Ardiyanti, A. R.; Wildschut, J.; Oasmaa, A.; Heeres, H. J. J. Chem. Technol. Biotechnol. 2010, 85 (5), 674–686. (3) Elliott, D. C. Historical developments in hydroprocessing bio-oils. Energy Fuels 2007, 21, 1792–1815. (4) Oasmaa, A. Fuel oil quality properties of wood-based pyrolysis liquids. Academic Dissertation, University of Jyv€ askyl€ a, Jyv€ askyl€ a, Finland, 2003; 32 pages þ appendix 251 pages; Research Report Series, Report 99, ISBN 951-39-1572-7 (5) de Miguel Mercader, F.; Groeneveld, M. J.; Kersten, S. R. A.; Way, N. W. J.; Schaverien, C. J.; Hogendoorn, J. A. Production of advanced biofuels: Co-processing of upgraded pyrolysis liquid in stan- dard refinery units. Appl. Catal., B: Environ. 2010, 96 (1-2), 57–66. (6) Oasmaa, A.; Kuoppala, E.; Solantausta, Y. Fast Pyrolysis of Forestry Residue. 2. Physicochemical Composition of Product Liquid. Energy Fuels 2003, 17 (2), 433–443. (7) Oasmaa, A.; Kuoppala, E. Solvent Fractionation Method with Brix for Rapid Characterisation of Wood Fast Pyrolysis Liquids. Energy Fuels 2008, 22 (6), 4245–4248.