Pyrolysis and liquefaction are promising processes for converting biomass into liquid bio-oils. However, upgrading of these bio-oils is typically needed to obtain properties that are compatible with processes for the production of chemicals and fungible gasoline additives. Hydrodeoxygenation (HDO) is an attractive approach for achieving this goal by replacing oxygen containing functional groups with hydrogen. In principle, water is formed as the only by-product. The process provides oils with reduced reactivity and corrosiveness and increases the energy density of the oil. Noble metal containing zeolite catalysts show considerable HDO activity, but deactivation remains an issue. In most studies, coking is assumed to be the cause of deactivation.<br/>Here, we show that additional deactivation paths need to be considered. Bifunctional aromatics, like catechol and guaiacol, can strongly adsorb on Lewis acid sites and form rigid surface species, so-called roadblocks, within the zeolite pores [1]. Consequently, the diffusion of reactants and products to and from active sites is hindered, and the catalyst deactivates. Importantly, roadblocks can drastically reduce the activity of zeolite catalysts even when only a fraction of the pore space is filled. In addition, dealumination processes during HDO will be discussed. Based on these results, it will be possible to design HDO catalysts and processes with significantly improved efficiency.

Deactivation paths during hydrodeoxygenation of aromatic oxygenates over Pt/H-BEA

253rd National Meeting (2017)

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