(114d) Investigation of Raney Nicu Catalysts for Hydrothermal Hydrodeoxygenation

Hydrodeoxygenation (HDO) of bio-oils is an essential process for producing drop in replacement fuels for conventional petroleum because HDO increases the energy density and decreases the viscosity of bio-oils. HDO is complicated by the water content of bio-oils from their initial processing [1] (pyrolysis, hydrothermal liquefaction, etc.) and by the water produced in the reaction when oxygen is removed because water causes catalyst instability due to transformations of catalyst supports and oxidation of active metals [2]. Noble metal catalysts are active and stable for high temperature and pressure HDO reactions in the presence of water, but are undesirable due to their high cost.

In a previous study we developed a low cost hydrothermal HDO catalyst by adding ~7 wt.% Cu to a Raney Ni 2800^® catalyst. The addition of Cu increased the product selectivity to liquid phase oxygenated and deoxygenated products, and away from gasification products in the hydrothermal HDO o-cresol. In this study, we examined the activity and selectivity of o-cresol HDO using Raney Ni doped with 1-40 wt.% Cu. Analysis of batch reactions indicated that at 380 °C the 1 and 2 % Raney NiCu catalysts gasified nearly all of the initial o-cresol to CH₄ and CO₂. Increasing the Cu content of the catalyst to 25 wt.% decreased the yield of gasification products to 12%, while maintaining a conversion of ~80%. We also examined the stability and of these Raney NiCu catalysts in a flow reactor. Catalyst characterization results from x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM) will also be presented.

REFERENCES

1.      J. G. Dickinson, J. T. Poberezny, P. E. Savage, Appl. Catal. B: Environ. 123-124, (2012) 357-366.

2.      T. M. Yeh, J. G. Dickinson, A. Franck, S. Linic, L. T. Thompson, P. E. Savage, J. Chem. Technol. Biotechnol. 88, (2013) 13-24.