Catalyst reactivation kinetics for methanol transformation into hydrocarbons. Expressions for designing reaction–regeneration cycles in isothermal and adiabatic fixed bed reactor

Role of internal coke for deactivation of ZSM-5 catalysts after low temperature removal of coke with NO2

“…This agrees well with the fact that the regeneration of a deactivated H-ZSM-5 catalyst with oxygen is done at 500-600 1C. 36,37 When NO 2 is used instead of O 2 , the onset of the CO 2 production is around 200 1C, and the maximum is reached at 400 1C. This indicates that NO 2 is much more reactive than oxygen, and is capable of removing coke from the zeolite at about 200 1C lower temperature compared to oxygen.…”

“…In industrial practice, a zeolite catalyst is regenerated by burning off the coke, despite the risk of damaging the catalyst. 36,37 To ensure a continuous production, a MTH plant typically has a few reactors in parallel, which are regenerated one by one, while the production continues in the other reactors. 1,38 The typical temperature for regeneration in oxygen (500-600 1C) is about 200 1C higher than that used in the MTH process.…”

Relating coke formation and characteristics to deactivation of ZSM-5 zeolite in methanol to gasoline conversion

“…In industrial practice, coke fouled ZSM-5 catalysts are subjected to regeneration to remove the coke by combustion in air (500-600 °C) [20,48,49]. However, the activity of the catalyst cannot be fully restored [20,50]. Such degradation is believed to be mainly due to the loss of Al by hydrolysis during the reaction and regeneration.…”

Recent advances in hydrogenation of CO2 into hydrocarbons via methanol intermediate over heterogeneous catalysts

“…259 Gayubo et al presented extensive modeling on MTO reaction kinetics with SAPO catalysts. [260][261][262][263] They proposed a kinetic model for the conversion of methanol to olefins over a SAPO-34 catalyst and further extended their studies on a SAPO-18 catalyst for a wide range of experimental conditions. Fig.…”

“…Initially the production rate increases, later it passes through a maximum, where the concentration of the active intermediates reaches the maximum, followed by a reduction when deactivation causes a degeneration of the intermediates to form coke. [260][261][262][263] The same group also proposed a kinetic model including the effect of water on the MTG reaction kinetics on the HZSM-5 catalyst. They further extended the study by considering the effect of water in the kinetic model for catalyst deactivation.…”