Regulating the size and acidity of SAPO-34 zeolites using dual templates to enhance the selectivity of light olefins in MTO

2021 ◽  
Author(s):  
Jihui Yao ◽  
Haifeng Tian ◽  
Fei Zha ◽  
Shizi Ma ◽  
Xiaohua Tang ◽  
...  
Keyword(s):  
Catalytic Performance ◽  
Light Olefins ◽  
Crystalline Size ◽  
Hydrothermal Crystallization ◽  
Relationship Of

To understand relationship of catalytic performance with crystalline size and acidity of SAPO-34 zeolites better, a series of SAPO-34 zeolites were prepared by hydrothermal crystallization using palygorskite as silicon and...

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.

Synthesis of SAPO-34 using N-octyl-d-glucamine as additive for enhanced catalytic performance in CH3Br conversion to light olefins

2017 ◽  
Vol 441 ◽  
pp. 109-113 ◽  
Author(s):  
Jun Xie ◽  
Na Li ◽  
Peng Wang ◽  
Lang Chen ◽  
Chak-Tong Au ◽  
...  
Keyword(s):  
Catalytic Performance ◽  
Light Olefins

Effect of preparation methods on the structure and catalytic performance of Fe–Zn/K catalysts for CO 2 hydrogenation to light olefins

2018 ◽  
Vol 26 (4) ◽  
pp. 761-767 ◽  
Author(s):  
Xu Wang ◽  
Jianli Zhang ◽  
Jingyu Chen ◽  
Qingxiang Ma ◽  
Subing Fan ◽  
...  
Keyword(s):  
Catalytic Performance ◽  
Light Olefins ◽  
Preparation Methods

Catalytic performance of chloromethane transformation for light olefins production over SAPO-34 with different Si content

2007 ◽  
Vol 114 (1-2) ◽  
pp. 30-35 ◽  
Author(s):  
Yingxu Wei ◽  
Dazhi Zhang ◽  
Yanli He ◽  
Lei Xu ◽  
Yue Yang ◽  
...  
Keyword(s):  
Catalytic Performance ◽  
Light Olefins ◽  
Si Content

Fischer–Tropsch synthesis over the Fe–Mn/Al2O3 catalyst: modeling and optimization of light olefins using the RSM method

2020 ◽  
Vol 44 (42) ◽  
pp. 18457-18468
Author(s):  
Maryam Arsalanfar
Keyword(s):  
Chemical Properties ◽  
Catalytic Performance ◽  
Tropsch Synthesis ◽  
Light Olefins ◽  
Fischer Tropsch ◽  
Fischer Tropsch Synthesis ◽  
Modeling And Optimization ◽  
Physico Chemical ◽  
Al2o3 Catalyst

The effect of various preparation parameters on the catalytic performance and physico-chemical properties of a supported Fe–Mn catalyst was investigated using the RSM method.

scholarly journals Understanding Hydrodechlorination of Chloromethanes. Past and Future of the Technology

Catalysts ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1462
Author(s):  
Sichen Liu ◽  
Javier A. Otero ◽  
Maria Martin-Martinez ◽  
Daniel Rodriguez-Franco ◽  
Juan J. Rodriguez ◽  
...  
Keyword(s):  
Catalyst Deactivation ◽  
Global Analysis ◽  
Catalytic Performance ◽  
Operating Conditions ◽  
Light Olefins ◽  
Synthesis Methods ◽  
Chlorinated Pollutants ◽  
New Perspective ◽  
Kinetics Of ◽  
Experimental And Theoretical Studies

Chloromethanes are a group of volatile organic compounds that are harmful to the environment and human health. Abundant studies have verified that hydrodechlorination might be an effective treatment to remove these chlorinated pollutants. The most outstanding advantages of this technique are the moderate operating conditions used and the possibility of obtaining less hazardous valuable products. This review presents a global analysis of experimental and theoretical studies regarding the hydrodechlorination of chloromethanes. The catalysts used and their synthesis methods are summarized. Their physicochemical properties are analyzed in order to deeply understand their influence on the catalytic performance. Moreover, the main causes of the catalyst deactivation are explained, and prevention and regeneration methods are suggested. The reaction systems used and the effect of the operating conditions on the catalytic activity are also analyzed. Besides, the mechanisms and kinetics of the process at the atomic level are reviewed. Finally, a new perspective for the upgrading of chloromethanes, via hydrodechlorination, to valuable hydrocarbons for industry, such as light olefins, is discussed.

Enhanced Catalytic Activity of Carbon Nanotubes for the Oxidation of Cyclohexane by Filling with Fe, Ni, and FeNi alloy Nanowires

2016 ◽  
Vol 69 (6) ◽  
pp. 689 ◽  
Author(s):  
Xixian Yang ◽  
Yuhang Li ◽  
Hao Yu ◽  
Xuchun Gui ◽  
Hongjuan Wang ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Catalytic Activity ◽  
Wall Thickness ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Catalytic Performance ◽  
General Strategy ◽  
Thin Walls ◽  
Alloy Nanowires ◽  
Relationship Of

Fe-, Ni-, and alloyed FeNi-filled carbon nanotubes (Fe@CNT, Ni@CNT, and FeNi@CNT) were prepared by a general strategy using a mixture of xylene and dichlorobenzene as carbon source, and ferrocene, nickelocene, and their mixture as catalysts. By tailoring the composition of the carbon precursor, the filling ratio and the wall thickness of metal@CNT could be controlled. For the catalytic oxidation of cyclohexane in liquid phase with molecular oxygen as oxidant, the highest activity was obtained over Fe@CNT synthesized from pure dichlorobenzene. However, Ni filling did not improve the activity of CNTs. The effects of metal filling, wall thickness, and defects on catalytic activity were investigated to determine the structure–activity relationship of the filled CNTs. The enhanced catalytic performance can be attributed to a combined contribution of thin walls of CNTs and confined electron-donating metals, which are favourable to electron transfer on the surfaces of CNTs. The modification of the electronic structure of CNTs upon Fe and Ni fillers insertion was elucidated through density functional theory calculations.

Production of Light Olefins Through Catalytic Cracking of C5 Raffinate Over Surface-Modified ZSM-5 Catalyst

2015 ◽  
Vol 15 (10) ◽  
pp. 8311-8317 ◽  
Author(s):  
Joongwon Lee ◽  
Seungwon Park ◽  
Ung Gi Hong ◽  
Jin Oh Jun ◽  
In Kyu Song
Keyword(s):  
Surface Modification ◽  
Catalytic Cracking ◽  
Surface Acidity ◽  
Catalytic Performance ◽  
Light Olefins ◽  
Light Olefin ◽  
Olefin Production ◽  
Chemical Liquid Deposition ◽  
Surface Modified ◽  
Teos Content

Surface modification of phosphorous-containing porous ZSM-5 catalyst (P/C-ZSM5-Sil.(X)) was carried out by a chemical liquid deposition (CLD) method using tetraethyl orthosilicate (TEOS) as a silylation agent. Different amount of TEOS (X = 5, 10, 20, and 30 wt%) was introduced into P/C-ZSM5il.(X) catalysts for surface modification. The catalysts were used for the production of light olefins (ethylene and propylene) through catalytic cracking of C5 raffinate. It was found that external surface acidity of P/C-ZSM5-Sil.(X) catalysts significantly decreased with increasing TEOS content. In the catalytic reaction, both conversion of C5 raffinate and yield for light olefins showed volcano-shaped curves with respect to TEOS content. Among the catalysts tested, P/C-ZSM5- Sil.(20) catalyst exhibited the best catalytic performance in terms of conversion of C5 raffinate and yield for light olefins. Thus, an optimal TEOS content was required for CLD treatment to maximize light olefin production in the catalytic cracking of C5 raffinate over P/C-ZSM5-Sil.(X) catalysts.

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