Study on the deactivation and regeneration of the ZSM-5 catalyst used in methanol to olefins

Fluoride-mediated nano-sized high-silica ZSM-5 as an ultrastable catalyst for methanol conversion to propylene

“…ZSM-5 is known as an efficient catalyst for the MTP process because of its well-defined, three-dimensional 10ring microporous channel structure. However, the relatively narrow channel structure restricts the diffusion of products and the carbon precursor, thus leading to lower propylene selectivity and faster carbon deposition [5][6][7][8][9] . Zeolites could be used more efficiently if the diffusion path length of the micropore could be reduced by synthesis of nanocrystals or by mesopore formation in larger zeolite crystals, improving transport of molecules to and from the active sites [4,8,10] .…”

Dual-template synthesis of nanostructured CoAPSO-34 used in methanol to olefins: Effect of template combinations on catalytic performance and coke formation

“…Each of the applied templates affected the formation of special type of morphology which can afford additional evidence for the implementation of mixed template in the synthesis procedure. Surface of the catalytic particles of the CoS/TEA-DE and CoS/TEA-MO samples 10 are smoother than the surface of CoS/TEA-TE particles which can be attributed to their crystallinity. In other words, it seems that the samples with higher crystallinity appeared with much more smoother particles in FESEM micrographs.…”

“…Among the leading candidate catalysts, silicoaluminophosphate SAPO-34 molecular sieve exhibits higher selectivity toward light olefin [18][19][20][21]. However, it suffers from rapid deactivation by the blockage of pore mouth arisen from the coke formation [10]. Hence, the MTO process will need frequent regeneration of the catalyst.…”

“…Among several alternatives, the conversion of methanol to short chain olefins (MTO) has long been of great interest in the petrochemical industry as a potential means of providing demanded olefins in the future when crude oil becomes more expensive [4][5][6][7][8][9][10]. Methanol is one of the largest chemical commodities that can be produced from natural gas, biomass, or from coal via synthesis gas [3,[11][12][13].…”

Synergetic effect of Mn, Ce, Ba, and B modification and moderate desilication of nanostructured HZSM-5 catalyst on conversion of methanol to propylene

“…There is general agreement that coke formation on acid sites (especially strong acid sites) of the MTP catalyst is the main reason for catalyst deactivation. 8,64 The micropore channels of the HZSM-5 catalyst cause the reaction-produced molecules whose sizes are larger than those of trapped ZSM-5 channels and thereby form a coke precursor. Thus, coke is deposited on the pores and blocks the active acid sites and finally accelerates the catalyst deactivation.…”