Ex situ catalytic fast pyrolysis (CFP) is a promising route for the conversion of lignocellulosic biomass into renewable transportation fuels and blendstocks. In this process, biomass pyrolysis vapors are catalytically deoxygenated prior to condensation in order to improve oil properties and enhance chemical stability. Zeolites such as HZSM-5 are commonly employed in CFP processes because they are effective at deoxygenating biomass pyrolysis vapors to produce gasoline range aromatic hydrocarbons. However, zeolites suffer from low liquid yields and rapid deactivation, which necessitates the use of circulating bed reactor systems in order to facilitate frequent regeneration cycles. As an alternative approach, fixed bed upgrading in the presence of H2 may improve liquid yields by minimizing the production of carbon-containing light gasses and catalyst coking. In this contribution we report on the technical and economic viability of Pt/TiO2 as a fixed bed catalyst for ex situ CFP. Based on model compound experiments and density functional theory calculations, it is proposed that reactions at or near the metal-support interface increase deoxygenation. Building on these initial results, the performance of Pt/TiO2 was evaluated for the continuous upgrading of pine pyrolysis vapors using a fixed bed reactor at the 100 gcat scale. The catalyst exhibited no apparent loss in activity over 20+ regeneration cycles, and &gt;500 mL of upgraded bio-oil was condensed, hydrotreated, and analyzed for fuel properties. These data, which are summarized in Table 1, highlight the potential for higher carbon yields and improved deoxygenation performance using Pt/TiO2 compared to HZSM-5. A technoeconmic analysis, which was performed based on the Pt/TiO2 results, identified opportunities to further reduce costs for this biomass conversion process. Among the most economically impactful technical targets are efforts to reduce catalyst precious metal content, improve regeneration efficiency, and increase liquid yields.

Ex situ catalytic fast pyrolysis over Pt/TiO2: Fixed bed hydrodeoxygenation followed by hydrotreating to produce fuel blendstocks

255th National Meeting (2018)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.