Coke and HC ratio profiles on A Cr2O3Al2O3 catalyst during the butene-1 dehydrogenation reaction

Variation in Structural Characteristics of a Hydrotreatment Catalyst with Deactivation/Regeneration Cycles

“…These results are comparable with those of Brito et al (1996), who also find for Cr 2 O 3 /Al 2 O 3 catalysts that the only factor which really influences coke composition at any point in the bed is the coke concentration there and not the reaction history. This result allows coke composition in the bed to be found simply by measuring its concentration without the need to determine the hydrogen concentration, independently of conditions previously used in that reactor.…”

“…Thus, when coke concentration increases, its hydrogen content decreases, as found by Hashimoto et al (1983), Dı ´ez et al (1980), Garcı ´a-Ochoa and Santos (1996), and Brito et al (1996. However, this reduction is not as pronounced above 5% coke concentrations.…”

In Situ Ultraviolet Raman Spectroscopy of the Reduction of Chromia on Alumina Catalysts

“…Supported chromium oxide catalysts are used for many industrial catalytic processes . Chromium oxide supported on alumina is used as a catalyst for propane and butane dehydrogenation. − Determination of the surface structure under reaction conditions is important for a complete understanding of the catalyst system.…”

A novel reverse flow reactor coupling endothermic and exothermic reactions

“…Operation with short propane dehydrogenation and regeneration cycles has the distinct advantage of operation at a relatively low coke content at the catalyst surface with the corresponding high catalyst activity and an easy coke removal without deteriorating the catalyst properties. The short time on stream during the dehydrogenation process step assures high hydrogen to carbon ratios of the coke (Brito et al, 1996), which can be combusted completely with short regeneration times. The inherently fast catalyst regeneration therefor allows operation at higher temperatures (or lower hydrogen concentrations) with higher propylene yields.…”

“…Subsequently, fast catalyst regeneration allows operation of the endothermic propane dehydrogenation reaction phase at more severe reaction conditions, because the shorter the time on stream, the smaller the amount of coke deposited and the larger the hydrogen to carbon ratio of the coke (Brito et al, 1996), either facilitating the burning of the coke. Thus, the fast catalyst regeneration allows operation at higher temperatures and lower hydrogen concentrations with higher equilibrium conversions.…”