Kinetics of Methanol Transformation into Hydrocarbons on a HZSM-5 Zeolite Catalyst at High Temperature (400−550 °C)

Abstract

A kinetic model of seven lumps has been established which allows the quantification of the product distribution (oxygenates, n-butane, C 2 -C 4 olefins, C 2 -C 4 paraffins (without n-butane), C 5-C 10 fraction, methane) in the transformation of methanol into hydrocarbons at high temperature (400-550 °C) on a HZSM-5 zeolite catalyst (SiO 2 /Al 2 O 3 ) 30) with high acidic strength (>120 kJ (mol of NH 3 ) -1 ) and agglomerated with bentonite and alumina. The kinetic model fits well the experimental data obtained in a fixed bed reactor, from small values of space time in which the formation of hydrocarbons is incipient, to a space time of 2.4 (g of catalyst) h (mol CH 2 ) -1 for a complete conversion of methanol. The rise in temperature increases the yield of C 2 -C 4 olefins, so that the maximum value (∼50%) is obtained at the ceiling temperature for the hydrothermal stability of the HZSM-5 (550 °C) and space times between 0.6 and 1 (g of catalyst) h (mol CH 2 ) -1 .

Kinetic modelling for the transformation of bioethanol into olefins on a hydrothermally stable Ni–HZSM-5 catalyst considering the deactivation by coke

“…The MTO process is performed with SAPO-34 catalyst, although it was originally studied using HZSM-5 zeolites and is still being studied due to the possibilities for modifying this zeolite acid structure [28,[47][48][49][50][51][52]. The main similarities to highlight are: temperature is similar (around 400 • C in the MTO process); the main objective is the same (selective propylene production); water is co-fed in both processes (in the MTO process to attenuate deactivation by coke) and their kinetic schemes are very similar, with C 2 -C 4 olefins as intermediates and the formation of paraffins and aromatics as by-products.…”

Kinetic modeling of C2–C7 olefins interconversion over ZSM-5 catalyst

“…396 397 398 The methodology used for the kinetic modeling is similar to the 399 way proposed by Aguayo and co-workers [19,30]. Plug flow 400 behavior has been assumed in the fixed bed reactor and then the 401 mass balance for each lump can be expressed as:…”

Kinetics of methanol to olefins over AlPO4-bound ZSM-5 extrudates in a two-stage unit with dimethyl ether pre-reactor

“…However, Gayubo et al developed a kinetic model for a temperature range up to 450°C, taking into account cracking reactions to light olefins [17]. A further model by Aguayo et al quantifies the product distribution at even higher temperatures (400-550°C), but it has been developed for the CMHC process (coupled methanol and hydrocarbons cracking), in which zeolites with high total acidity are used [18]. Another high-temperature model stems from Kaarsholm et al who used phosphorous-modified ZSM-5 catalyst with moderate acid strength [19].…”

“…In most studies, shaped catalysts were employed consisting of zeolite as the active phase and aluminum-containing binder materials like bentonite, kaolin and alumina [11][12][13][14][15][17][18][19]. However, it cannot be excluded in general that the density of acid sites may change with the use of such binder materials.…”