(349f) High Pressure Fast-Pyrolysis and Fast-Hydropyrolysis for Conversion of Biomass to Liquid Fuels

The transportation sector has been heavily dependent on the use of liquid fuels produced from fossil-based petroleum sources. In the context of a petroleum-deprived future, it is imperative to look for sustainable carbon sources in conjunction with more efficient process pathways for producing high-energy-density liquid fuels. Sustainably available (SA) biomass comprised of crop and forest residues, agriculture and municipal waste, etc. is one such carbon source for producing liquid fuels to meet the large demand for transportation. Among the traditional routes for biomass conversion to liquid fuel, the fast-pyrolysis process, involving rapid heating of biomass at near atmospheric pressure to temperatures of ~500-550 °C, is known to produce a high oxygen content, acidic liquid product with a similar energy content as the feed biomass and requiring further processing under severe conditions to be upgraded to transportation grade fuel. As an alternative to this two step approach, we look at a novel H₂Bioil ¹ process based on continuous fast-hydropyrolysis, which includes fast-pyrolysis in a moderate to high-pressure (upto 50 bar) hydrogen environment to produce hydropyrolysis vapors which are upgraded in the vapor phase by catalytic hydrodeoxygenation and quenched to form a high-energy-density, deoxygenated liquid product that can supplement petroleum-based liquid fuels or potentially be used directly as a fuel.

In this presentation we summarize our reactor design and on-going process development to achieve high-pressure fast-pyrolysis and fast-hydropyrolysis of cellulose and lignocellulosic materials. Furthermore, the role played by hydrogen in fast-hydropyrolysis will be briefly discussed, by comparison with high-pressure inert gas fast-pyrolysis experiments with model and real biomass feedstocks. In addition to basic oil analysis techniques such as elemental analysis, Karl-Fischer, and TAN, we have utilized atmospheric-pressure, chemical-ionization mass spectrometry (APCI-MS) to identify and quantitatively compare major product species present in the liquid product.  Investigation of the effect of catalysts on the hydrodeoxygenation process will also be presented.

¹Agrawal R, Singh NR. Synergistic Routes to Liquid Fuel for a Petroleum-Deprived Future, AIChE J. 2009; 55: 1898-1905