Coke Forming Reactions During Methanol Conversion on Zeolite Catalysts

Catalyst Deactivation by Coke in the Transformation of Aqueous Ethanol into Hydrocarbons. Kinetic Modeling and Acidity Deterioration of the Catalyst

“…[37][38][39][40][41][42] It is a consequence of the shape selectivity of the zeolite (which limits the condensation of aromatic rings in the internal channels of the crystals); 43 the moderate strength of the acid sites; the presence of water, which attenuates the evolution of coke precursors; and the capacity of the zeolite for cracking the oligomers that make up the coke forming above 400°C. 36 Figure 4, the distributions of acidity strength determined for the fresh catalyst (upper graph) and for a deactivated catalyst (lower graph) are compared.…”

Role of water in the kinetic modeling of catalyst deactivation in the MTG process

“…etable oils Sharma and Bakhshi, 1991 . On the other hand, the peculiarities of the coke deposited in the MTG process must be taken into account. Thus, because of the limitations on coke development due to the shape selectivity of the HZSM-5 zeolite, this coke is highly hydrogenated and unstable and, consequently, it may suffer thermal degradation or it may be swept out when a vacuum is Ž created Schulz et al, 1987;Sexton et al, 1988;Bibby et al, 1992;Dimon et al, 1993;Aguayo et al, 1994;Guisnet and . Magnoux, 1994 .…”

Role of Coke Characteristics in the Regeneration of a Catalyst for the MTG Process

“…The coke deposited on HZSM5 zeolites is more hydrogenated than that deposited on other catalysts, and its H/C ratio is dependant on reaction conditions (Dejaifve et al, 1981;Schulz et al, 1987;Sexton et al, 1988;Meinhold and Bibby, 1990). It is slightly developed coke, with low molecular weight components (in the 200-300 mass unit range), which consists of alkylated biaromatics as heavier hydrocarbons (Aguayo et al, 1994).…”