scholarly journals Methanol-to-olefins process over zeolite catalysts with DDR topology: effect of composition and structural defects on catalytic performance

2016 ◽  
Vol 6 (8) ◽  
pp. 2663-2678 ◽  
Author(s):  
Irina Yarulina ◽  
Joris Goetze ◽  
Canan Gücüyener ◽  
Leonard van Thiel ◽  
Alla Dikhtiarenko ◽  
...  
Keyword(s):  
Physicochemical Properties ◽  
Catalyst Deactivation ◽  
Catalytic Performance ◽  
Zeolite Catalysts ◽  
Structural Defects ◽  
Ethylene Propylene ◽  
Mto Reaction ◽  
Sigma 1 ◽  
Olefin Selectivity

The effect of physicochemical properties on catalyst deactivation, overall olefin selectivity and ethylene/propylene ratio during the methanol-to-olefins (MTO) reaction is presented for two zeolites with the DDR topology, Sigma-1 and ZSM-58.

Ni/Y- Zeolite Catalysts for Carbon Dioxide Reforming of Methane

2012 ◽  
Vol 550-553 ◽  
pp. 325-328 ◽  
Author(s):  
A.H. Fakeeha ◽  
A.S. Al–Fatesh ◽  
A.E. Abasaeed
Keyword(s):  
Catalyst Deactivation ◽  
Tubular Reactor ◽  
Catalytic Performance ◽  
Zeolite Catalysts ◽  
Incipient Wetness Impregnation ◽  
Y Zeolite ◽  
Ni Catalysts ◽  
Carbon Deposits ◽  
Temperature Ranges ◽  
Supported Ni

Carbon deposits play a crucial role in the performance of catalysts, in terms of controlling both reaction selectivity and activity, this is most often manifest through catalyst deactivation. Understanding the structure and electronic properties of the carbon deposits formed on the surface of a catalyst is therefore an importance key. In this study the catalytic performance of Ni based on Y-Zeolite (CBV300) prepared by incipient wetness impregnation. The prepared catalyst was tested in a micro tubular reactor using temperature ranges of 500, 600 and 700 °C at atmospheric pressure, using a total flow rate of 36 ml/min consisting of 2 ml/min of N2, 17 ml/min of CO2and 17 ml/min of CH4. The calcination was carried out in the range of 500–900 °C. The catalyst is activated inside the reactor using hydrogen gas.The conversion of CH4observed over 5wt%Ni/ Y-Zeolite at 700 °C were 59.6%. The supported Ni catalysts were characterized by BET and TG/DTA techniques.

Structural/Texture Evolution During Facile Substitution of Ni into ZSM-5 Nanostructure vs. its Impregnation Dispersion Used in Selective Transformation of Methanol to Ethylene and Propylene

2020 ◽  
Vol 23 ◽  
Author(s):  
Parisa Sadeghpour ◽  
Mohammad Haghighi ◽  
Mehrdad Esmaeili
Keyword(s):  
High Temperature ◽  
Physicochemical Properties ◽  
Active Sites ◽  
Catalytic Performance ◽  
Fixed Bed Reactor ◽  
Light Olefins ◽  
Isomorphous Substitution ◽  
Impregnation Method ◽  
Hydrothermal Temperature ◽  
X Ray

Aim and Objective: Effect of two different modification methods for introducing Ni into ZSM-5 framework was investigated under high temperature synthesis conditions. The nickel successfully introduced into the MFI structures at different crystallization conditions to enhance the physicochemical properties and catalytic performance. Materials and Methods: A series of impregnated Ni/ZSM-5 and isomorphous substituted NiZSM-5 nanostructure catalysts were prepared hydrothermally at different high temperatures and within short times. X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), Energy dispersive X-ray (EDX), Brunner, Emmett and Teller-Barrett, Joyner and Halenda (BET-BJH), Fourier transform infrared (FTIR) and Temperature-programmed desorption of ammonia (TPDNH3) were applied to investigate the physicochemical properties. Results: Although all the catalysts showed pure silica MFI–type nanosheets and coffin-like morphology, using the isomorphous substitution for Ni incorporation into the ZSM-5 framework led to the formation of materials with lower crystallinity, higher pore volume and stronger acidity compared to using impregnation method. Moreover, it was found that raising the hydrothermal temperature increased the crystallinity and enhanced more uniform incorporation of Ni atoms in the crystalline structure of catalysts. TPD-NH3 analysis demonstrated that high crystallization temperature and short crystallization time of NiZSM-5(350-0.5) resulted in fewer weak acid sites and medium acid strength. The MTO catalytic performance was tested in a fixed bed reactor at 460ºC and GHSV=10500 cm3 /gcat.h. A slightly different reaction pathway was proposed for the production of light olefins over impregnated Ni/ZSM-5 catalysts based on the role of NiO species. The enhanced methanol conversion for isomorphous substituted NiZSM-5 catalysts could be related to the most accessible active sites located inside the pores. Conclusion: The impregnated Ni/ZSM-5 catalyst prepared at low hydrothermal temperature showed the best catalytic performance, while the isomorphous substituted NiZSM-5 prepared at high temperature was found to be the active molecular sieve regarding the stability performance.

scholarly journals A diffusion anisotropy descriptor links morphology effects of H-ZSM-5 zeolites to their catalytic cracking performance

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Xiaoliang Liu ◽  
Jing Shi ◽  
Guang Yang ◽  
Jian Zhou ◽  
Chuanming Wang ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Catalytic Cracking ◽  
Catalytic Performance ◽  
Zeolite Catalysts ◽  
Time Resolved ◽  
Cracking Performance ◽  
Morphology Effect ◽  
Ft Ir ◽  
The Difference ◽  
Dynamics Simulations

AbstractZeolite morphology is crucial in determining their catalytic activity, selectivity and stability, but quantitative descriptors of such a morphology effect are challenging to define. Here we introduce a descriptor that accounts for the morphology effect in the catalytic performances of H-ZSM-5 zeolite for C4 olefin catalytic cracking. A series of H-ZSM-5 zeolites with similar sheet-like morphology but different c-axis lengths were synthesized. We found that the catalytic activity and stability is improved in samples with longer c-axis. Combining time-resolved in-situ FT-IR spectroscopy with molecular dynamics simulations, we show that the difference in catalytic performance can be attributed to the anisotropy of the intracrystalline diffusive propensity of the olefins in different channels. Our descriptor offers mechanistic insight for the design of highly effective zeolite catalysts for olefin cracking.

Co-Cr bimetallic oxide derived from layered double hydroxides with high catalytic performance for chlorinated aromatics oxidation

2021 ◽  
Author(s):  
Wei Deng ◽  
Biao Gao ◽  
Ziye Jia ◽  
Dongqi Liu ◽  
Limin Guo
Keyword(s):  
Physicochemical Properties ◽  
Layered Double Hydroxides ◽  
Catalytic Performance ◽  
Chlorinated Aromatics ◽  
Molar Ratios ◽  
Double Hydroxides

Co-Cr bimetallic oxide with different Co/Cr molar ratios were prepared through a layered double hydroxides (LDHs) derived method. Their physicochemical properties together with catalytic performance for chlorinated aromatics (1, 2-dichlorobenzene...

Rational construction of hierarchical SAPO-34 with enhanced MTO performance without an additional meso/macropore template

2021 ◽  
Author(s):  
Yafei Liang ◽  
Beibei Gao ◽  
Lipeng Zhou ◽  
Xiaomei Yang ◽  
Tianliang Lu ◽  
...  
Keyword(s):  
Catalytic Performance ◽  
Mto Reaction ◽  
Rational Construction ◽  
Excellent Catalytic Performance

A facile approach has been developed to fabricate hierarchical SAPO-34 with large intracrystalline meso/macropores and excellent catalytic performance in the MTO reaction.

scholarly journals Things go better with coke: the beneficial role of carbonaceous deposits in heterogeneous catalysis

2016 ◽  
Vol 6 (2) ◽  
pp. 363-378 ◽  
Author(s):  
C. H. Collett ◽  
J. McGregor
Keyword(s):  
Heterogeneous Catalysis ◽  
Heterogeneous Catalysts ◽  
Catalyst Deactivation ◽  
Catalytic Performance ◽  
Fischer Tropsch ◽  
Carbonaceous Deposits ◽  
Beneficial Role ◽  
Catalytic Processes

Carbonaceous deposits on heterogeneous catalysts are traditionally associated with catalyst deactivation. However, they can play a beneficial role in many catalytic processes, e.g. dehydrogenation, hydrogenation, alkylation, isomerisation, Fischer–Tropsch, MTO etc. This review highlights the role and mechanism by which coke deposits can enhance catalytic performance.

Optimization of Redox and Catalytic Performance of LaFeO3 Perovskites: Synthesis and Physicochemical Properties

2019 ◽  
Vol 48 (7) ◽  
pp. 4351-4361
Author(s):  
Anees A. Ansari ◽  
Naushad Ahmad ◽  
Manawwer Alam ◽  
Syed F. Adil ◽  
Mohamed E. Assal ◽  
...  
Keyword(s):  
Physicochemical Properties ◽  
Catalytic Performance

Catalytic performance of MoO3/FAU zeolite catalysts modified by Cu for reverse water gas shift reaction

2020 ◽  
Vol 592 ◽  
pp. 117415 ◽  
Author(s):  
Atsushi Okemoto ◽  
Makoto R. Harada ◽  
Takayuki Ishizaka ◽  
Norihito Hiyoshi ◽  
Koichi Sato
Keyword(s):  
Catalytic Performance ◽  
Zeolite Catalysts ◽  
Water Gas Shift ◽  
Water Gas Shift Reaction ◽  
Fau Zeolite ◽  
Reverse Water Gas Shift ◽  
Shift Reaction ◽  
Water Gas
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