Behaviors of coke deposition on SAPO-34 catalyst during methanol conversion to light olefins

SnxOy/SAPO-34 as catalysts for catalytic dehydration of bio-ethanol: impacts of oxidation state, interaction, and loading amount

“…79 Firstly reported by a group of Union Carbide's researchers, silicoaluminophosphate 80 material (SAPO-n) is a family of molecular sieves resulted from the substitution of silicon into 81 the framework of aluminophosphate (AlPO) molecular sieves during preparation (Lok,et al,82 1984). Among SAPO-n, SAPO-34, whose structure is chabazite, with 0.43 nm pore size is the 83 most frequently employed as a catalyst or a support such as methanol-to-olefins (MTO) reaction 84 (Smith et al, 2015) with possible coke formation (Qi, et al, 2007 spectrometer to determine the oxidation state of a metal oxide before and after catalytic testing. 144 The system was equipped with a monochromatic Al X-ray source and a hemispherical analyzer.…”

The Hydrocarbon Pool in Ethanol-to-Gasoline over HZSM-5 Catalysts

“…One challenge with the ETG process that can be envisioned when using ethanol as feed is a more rapid catalyst deactivation due to the formation of ethylene, which is a known coke precursor on H-ZSM-5 [28]. This deactivation could perhaps be inhibited by addition of water to the feed, [28,29] using lightly distilled bio-ethanol as the feed would add additional water to the reaction and slow down deactivation and lower the ethanol feed concentration. Our first effort towards this is to study the mechanism behind ETG through the analysis of retained material in the catalyst after the ethanol to gasoline reaction.…”

Green and efficient dry gel conversion synthesis of SAPO-34 catalyst with plate-like morphology

“…Among the SAPOs, SAPO-34 with a chabazite-related structure has exhibited excellent catalytic performance in the methanol-to-olefin (MTO) conversion due to its relatively small pore diameter (Pastore et al 2005), medium acid strength and high hydrothermal stability (Marchi and Froment 1991;Wei et al 2012;Wilson and Barger 1999). However, SAPO-34 is easily deactivated by coke, which can heavily block the internal channels of the SAPO-34 crystals and decrease both activity and selectivity, resulting in a short catalyst lifetime (Qi et al 2007; Lee et al 2007). During the MTO process, coke formation is related to many factors, such as Si/Al ratio (Xu et al 2008), acidity (Ye et al 2011), crystal morphology, as well as crystal size (Chen et al 1999;Á lvaro-Muñoz et al 2012), in which the catalyst acidity and size are two important factors.…”