Applied Catalysis A-general | 2021
Benzofuran as deactivation precursor molecule: Improving the stability of acid zeolites in biomass pyrolysis by co-feeding propylene
Abstract
Abstract Benzofuran (BZF) is produced during the biomass and waste pyrolysis, playing a key role in the catalytic deactivation in the processing of the resulting fractions, as well as in catalytic pyrolysis reactions. The transformation of this chemical over a typical pyrolysis catalyst (ZSM-5) is studied in this article. When this compound is processed alone, it presents a very high reactivity. At low temperature, the formation of large amount of coke precursors leads to a fast catalyst deactivation. As temperature increases, the weight of cracking reactions (yielding benzenes or naphtalenes) becomes more important, increasing the catalyst’s stability, although new polyaromatic carbon species are detected. A new strategy to minimize the deactivation caused by this compound, consisting of co-feeding propylene, is proposed. The presence of an alkene leads to the formation of alkylated derivatives of Diels-Alder condensation products, hindering their oligomerization capacity and minimizing the formation of polyaromatic coke deposits. Different temperatures and alkene/BZF ratios were tested, concluding that increasing the alkene concentration and the reaction temperature monotonously increase the catalyst’s stability in presence of BZF.