(111d) SUNFUEL: Conversion of Waste Biomass to Biofuels – Initial Spectroscopic and Small-Scale Continuous Flow Reactor Investigations in Supercritical Water

The use of sub- and super-critical water as a reaction medium for the conversion of biomass to fuels has been studied for various types of feedstock.[1,2] In the SUNFUEL project, we are studying (i) the dissolution and subsequent reaction of real biomass feedstocks in this high-temperature environment, (ii) the optimisation of a reactor design for biofuel production, and (iii) testing the fuel products for combustion properties. In this paper, we present our initial results on this project, viz. vibrational spectroscopic data from a hydrothermal diamond-anvil cell (HDAC) and information obtained from studies using a small-scale continuous flow reactor. In this first stage of the project, we have considered pinewood and pinewood waste as the feedstock. This feedstock is of considerable interest because large quantities of mountain pine beetle-infested lodgepole pine from Western Canada may be available as a feedstock for fuel production.[3] Moreover, recent reports on the potential of this particular infestation to spread to Eastern Canada [4] have also prompted us to consider this material as a feedstock. The dissolution of biomass can be conveniently visualised using a hydrothermal diamond-anvil cell.[5,6] We will report our initial results on the application of vibrational spectroscopy using the HDAC to study the fundamental processes involved in the dissolution of biomass and in its transformations into bio-oil and gases. We will also report our data from experiments employing a small-scale continuous flow reactor. In addition to the effects of residence time, pressure and temperature on the process, we will suggest improvements to the reactor design that will facilitate the tuning of the reaction to produce optimal yields of selected products. In our future work, we intend to further optimize the reactor design, to investigate the possibility for further processing of our liquid and gaseous products, and to study the potential for use of the secondary product, biochar, produced as a solid residue under some conditions. We also plan to investigate a variety of other biomass feedstocks.

1. Matsumura et al., Biomass gasification in near- and super-critical water: Status and prospects, Biomass and Bioenergy, 2005, 29, 269-292. 2. Osada et al., Catalytic gasification of wood biomass in subcritical and supercritical water, Combustion Science and Technology, 2006, 178, 537-552. 3. B. Stennes and A. McBeath, Bioenergy options for woody feedstock: are trees killed by mountain pine beetle in British Columbia a viable bioenergy resource?, Information report, BC-X-405, 2006, Natural Resources Canada, Canadian Forest Service, Pacific Forest Service. 4. A.V. Rice and D.W. Langor, Mountain pine beetle-associated blue-stain fungi in lodgepole x jack pine hybrids near Grand Prairie, Alberta (Canada), Forest Pathology, 2009, 39, 323-334. 5. R. Hashaikeh et al., Hydrothermal dissolution of willow in hot compressed water as a model for biomass conversion, Fuel, 2007, 86, 1614-1622. 6. R. L. Smith and Z. Fang, Techniques, applications and future prospects of diamond anvil cells for studying supercritical water systems, Journal of Supercritical Fluids, 2009, 47, 431-446.