Compared with hydrocarbon chemistries, biomass conversion needs to deal with several unique characteristics, including high water/oxygen content, complex molecule structures with multiple functional sites, instabilities, presence of inorganic (Ca, K, Mg, etc) and organic (S and N containing molecules) impurities. Catalyst stability during biomass conversion could be very different from the fossil hydrocarbon chemistry applications, which requires extensive researches to understand the deactivation process and explore new approaches to mitigate the deactivation. Particularly for zeolite-based catalysis, deactivation mechanisms, such as dealumination, coke formation and metal sintering over metal modified zeolites, require better understanding to develop active and robust zeolite catalysts for biomass conversion. In this talk, we will summarize our studies on zeolite catalyst deactivations during 2,3-butanediol (BDO) and ethanol upgrading to olefins. For the conversion of 2,3-butanediol, Cu modified MFI zeolites showed stable conversion (~100%) for over 80 h at 1.0 gBDO/gcatalyst/h space velocity without regeneration, but decrease of olefin product selectivity was observed, which may be due to the formation of coke. Both Raman and STEM/EDS results will be shown to understand the coke species and coke distributions. The Cu site and Al site changes after &gt;100 h time on stream will be discussed. These analyses will help to identify the major deactivation mechanisms and inform potential strategies to mitigate the deactivation process. Similar methodologies will be shown to understand the deactivation of Cu modified BEA zeolites for ethanol upgrading reaction.

Zeolite catalyst deactivations during the conversion of bio-derived 2,3-butanediol and ethanol

2019 Spring National Meeting

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