Dimethyl ether to hydrocarbons over ZSM-5: Kinetic study in an external recycle reactor

Ortega, Carlos; Hessel, Volker; Kolb, Gunther

doi:10.1016/j.cej.2018.07.178

Cited by 19 publications

(27 citation statements)

References 62 publications

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“…The role of both cycles on a stable state catalyst depending on the conversion of DME has not yet been studied in detail: there are few investigations with stable catalyst at constant conversion only [24][25][26]. Detailed research into the chemistry over a partially deactivated and stable catalyst will allow development of a kinetic model and simulate the industrial reactor with the modification of the well-known lump models approaches [27,28].…”

Section: Introductionmentioning

confidence: 99%

Dimethyl Ether to Olefins over Modified ZSM-5 Based Catalysts Stabilized by Hydrothermal Treatment

et al. 2019

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The reaction of dimethyl ether to olefin over HZSM-5/Al2O3 catalysts modified by Zr and Mg and stabilized by hydrothermal treatment has been studied. Regardless of the introduction method and the nature of the metal, the dependence of the key products selectivity on X(DME) over hydrothermally treated steady-state catalysts does not change, and the experimental points are described by the same curves. Metal introduction and the corresponding changes in the acid sites distribution do not change the ratio of main reaction rates, only the absolute values of the formation rate of the products are changed. Zr doping leads to the greatest activity in the DME conversion due to an equable decrease in the total acidity of the sample. On the other hand, the Mg-modified sample has a higher amount of weak acid sites, which reduces activity. At low DME conversion, methanol is one of the primary reaction products which formed from DME simultaneously with propylene in alkene cycle. At high DME conversion, the methanol acts as a main reagent which leads to ethylene formation in the arene cycle. Based on the results, the role of the metal in the reaction chemistry is considered and the mechanism of product formation from DME over steady-state catalyst is proposed, which describes both the participation of DME and the methanol produced.

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Section: Introductionmentioning

confidence: 99%

Dimethyl Ether to Olefins over Modified ZSM-5 Based Catalysts Stabilized by Hydrothermal Treatment

et al. 2019

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“…This sized fraction was then used in the experimental tests. The details of the physicochemical characterization of this catalyst have been provided elsewhere. , …”

Section: Methodsmentioning

confidence: 99%

“…The CSTR behavior of the FBRR was characterized via residence time distribution (RTD) measurements using the pulse tracer technique. The detail of the RTD measurements have been reported elsewhere. , A by-pass in the reaction system allowed to measure the feed composition prior the reaction tests. The analysis of the feed mixture or of the product stream was performed with a gas chromatograph (GC).…”

Section: Methodsmentioning

confidence: 99%

DME-to-Hydrocarbon over an MFI Zeolite: Product Selectivity Controlled by Oxygenates under the Kinetic Regime

Ortega

Kolb

2019

Ind. Eng. Chem. Res.

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The influence of process variables on the DME-to-hydrocarbon (DtH) conversion has been assessed. The reaction was studied at atmospheric pressure, over an MFI zeolite (H-ZSM-5, SiO2/Al2O3 = 58), in a gradientless recycle reactor, under the kinetic regime, and process variables in the range of 598–648 K and space time in the range of 0.008–0.040 h kgcat kgDME –1. The results showed that DME and methanol are not in equilibrium, that the cis-/trans-C4 olefins are in equilibrium with each other but not with the 1-butene, while C5 + hydrocarbons are favored at high oxygenates conversion. Finally, it was observed for the first time, to best of the knowledge of the current authors, that under kinetically controlled conditions, the selectivity to main groups of products can be described by the oxygenates conversion (x oxy), independently of the process conditions, which means that the x oxy controls the process selectivity independently of reaction temperature and space time.

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“…Menges et al reported that the rate of butene production by methylation was 1.7 times faster than the rate of butene disappearance [47]. Ortega et al reported that butene was relatively stable because of the high activation energy of the butene disappearance rate [48]. As 720 NHA (FER) had a large amount of strong acid sites, which acted as active alkylation sites, the yields of hydrocarbons with many carbon atoms were higher than those with 840NHA (MFI) and 940HOA (BEA) (Table 2).…”

Section: Correlation Of Observed Values To N-butene Yieldmentioning

confidence: 99%

n-Butene Synthesis in the Dimethyl Ether-to-Olefin Reaction over Zeolites

2021

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Zeolite catalysts that could allow the efficient synthesis of n-butene, such as 1-butene, trans-2-butene, and cis-2-butene, in the dimethyl ether (DME)-to-olefin (DTO) reaction were investigated using a fixed-bed flow reactor. The zeolites were characterized by N2 adsorption and desorption, X-ray diffraction (XRD), thermogravimetry (TG), and NH3 temperature-programmed desorption (NH3-TPD). A screening of ten available zeolites indicated that the ferrierite zeolite with NH4+ as the cation showed the highest n-butene yield. The effect of the temperature of calcination as a pretreatment method on the catalytic performance was studied using three zeolites with suitable topologies. The calcination temperature significantly affected DME conversion and n-butene yield. The ferrierite zeolite showed the highest n-butene yield at a calcination temperature of 773 K. Multiple regression analysis was performed to determine the correlation between the six values obtained using N2 adsorption/desorption and NH3-TPD analyses, and the n-butene yield. The contribution rate of the strong acid site alone as an explanatory variable was 69.9%; however, the addition of micropore volume was statistically appropriate, leading to an increase in the contribution rate to 76.1%. Insights into the mechanism of n-butene synthesis in the DTO reaction were obtained using these parameters.

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Dimethyl ether to hydrocarbons over ZSM-5: Kinetic study in an external recycle reactor

Cited by 19 publications

References 62 publications

Dimethyl Ether to Olefins over Modified ZSM-5 Based Catalysts Stabilized by Hydrothermal Treatment

Dimethyl Ether to Olefins over Modified ZSM-5 Based Catalysts Stabilized by Hydrothermal Treatment

DME-to-Hydrocarbon over an MFI Zeolite: Product Selectivity Controlled by Oxygenates under the Kinetic Regime

n-Butene Synthesis in the Dimethyl Ether-to-Olefin Reaction over Zeolites

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