Pore size effects on physicochemical properties of Fe-Co/K-Al2O3 catalysts and their catalytic activity in CO2 hydrogenation to light olefins

2019 ◽  
Vol 483 ◽  
pp. 581-592 ◽  
Author(s):  
Thanapha Numpilai ◽  
Narong Chanlek ◽  
Yingyot Poo-Arporn ◽  
Suttipong Wannapaiboon ◽  
Chin Kui Cheng ◽  
...  
RSC Advances ◽  
2015 ◽  
Vol 5 (98) ◽  
pp. 80196-80202 ◽  
Author(s):  
Xiaojuan Su ◽  
Jianli Zhang ◽  
Subing Fan ◽  
Qingxiang Ma ◽  
Tian-Sheng Zhao

Small and uniform Fe–Zr–K particles with mesopores obtained by microwave assisted homogeneous precipitation show high catalytic activity and stability for the selective production of light olefins with low CO from CO2 hydrogenation.


Author(s):  
Parisa Sadeghpour ◽  
Mohammad Haghighi ◽  
Mehrdad Esmaeili

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.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yoottapong Klinthongchai ◽  
Seeroong Prichanont ◽  
Piyasan Praserthdam ◽  
Bunjerd Jongsomjit

AbstractMesocellular foam carbon (MCF-C) is one the captivating materials for using in gas phase dehydrogenation of ethanol. Extraordinary, enlarge pore size, high surface area, high acidity, and spherical shape with interconnected pore for high diffusion. In contrary, the occurrence of the coke is a majority causes for inhibiting the active sites on catalyst surface. Thus, this study aims to investigate the occurrence of the coke to optimize the higher catalytic activity, and also to avoid the coke formation. The MCF-C was synthesized and investigated using various techniques. MCF-C was spent in gas-phase dehydrogenation of ethanol under mild conditions. The deactivation of catalyst was investigated toward different conditions. Effects of reaction condition including different reaction temperatures of 300, 350, and 400 °C on the deactivation behaviors were determined. The results indicated that the operating temperature at 400 °C significantly retained the lowest change of ethanol conversion, which favored in the higher temperature. After running reaction, the physical properties as pore size, surface area, and pore volume of spent catalysts were decreased owing to the coke formation, which possibly blocked the pore that directly affected to the difficult diffusion of reactant and caused to be lower in catalytic activity. Furthermore, a slight decrease in either acidity or basicity was observed owing to consumption of reactant at surface of catalyst or chemical change on surface caused by coke formation. Therefore, it can remarkably choose the suitable operating temperature to avoid deactivation of catalyst, and then optimize the ethanol conversion or yield of acetaldehyde.


Reactions ◽  
2021 ◽  
Vol 2 (3) ◽  
pp. 227-257
Author(s):  
Arash Yahyazadeh ◽  
Ajay K. Dalai ◽  
Wenping Ma ◽  
Lifeng Zhang

Light olefins as one the most important building blocks in chemical industry can be produced via Fischer–Tropsch synthesis (FTS) from syngas. FT synthesis conducted at high temperature would lead to light paraffins, carbon dioxide, methane, and C5+ longer chain hydrocarbons. The present work focuses on providing a critical review on the light olefin production using Fischer–Tropsch synthesis. The effects of metals, promoters and supports as the most influential parameters on the catalytic performance of catalysts are discussed meticulously. Fe and Co as the main active metals in FT catalysts are investigated in terms of pore size, crystal size, and crystal phase for obtaining desirable light olefin selectivity. Larger pore size of Fe-based catalysts is suggested to increase olefin selectivity via suppressing 1-olefin readsorption and secondary reactions. Iron carbide as the most probable phase of Fe-based catalysts is proposed for light olefin generation via FTS. Smaller crystal size of Co active metal leads to higher olefin selectivity. Hexagonal close-packed (HCP) structure of Co has higher FTS activity than face-centered cubic (FCC) structure. Transition from Co to Co3C is mainly proposed for formation of light olefins over Co-based catalysts. Moreover, various catalysts’ deactivation routes are reviewed. Additionally, techno-economic assessment of FTS plants in terms of different costs including capital expenditure and minimum fuel selling price are presented based on the most recent literature. Finally, the potential for global environmental impacts associated with FTS plants including atmospheric and toxicological impacts is considered via lifecycle assessment (LCA).


2021 ◽  
Vol 9 (2) ◽  
pp. 105071
Author(s):  
Paraskevi Ntzoufra ◽  
John Vakros ◽  
Zacharias Frontistis ◽  
Sotirios Tsatsos ◽  
Georgios Kyriakou ◽  
...  

2014 ◽  
Vol 53 (45) ◽  
pp. 17563-17569 ◽  
Author(s):  
Fanshu Ding ◽  
Anfeng Zhang ◽  
Min Liu ◽  
Yi Zuo ◽  
Keyan Li ◽  
...  

2011 ◽  
Vol 347-353 ◽  
pp. 3681-3684 ◽  
Author(s):  
Young Ho Kim ◽  
Su Gyung Lee ◽  
Byoung Kwan Yoo ◽  
Han Sol Je ◽  
Chu Sik Park

A SAPO-34 catalyst is well known to be one of the best catalysts for DME to olefins (DTO) reaction. Main products of the reaction were light olefins such as ethylene, propylene and butenes. However, the main problem is rapid deactivation of the SAPO-34 catalyst due to coke deposition during DTO reaction. In this study, various SAPO-34/ZrO2 catalysts added with ZrO2 were prepared for improving the lifetime and their physicochemical properties have been characterized by XRD and SEM. The DTO reaction over various SAPO-34/ZrO2 catalysts was carried out using a fixed bed reactor. All SAPO-34/ZrO2 catalysts showed similar activity and selectivity in the DTO reaction. The SAPO-34(9wt%)/ZrO2 catalyst was showed the best performance for the catalyst lifetime.


Author(s):  
Cássia S. Santana ◽  
Luiza S. Shine ◽  
Luiz H. Vieira ◽  
Ricardo J. Passini ◽  
Ernesto A. Urquieta-González ◽  
...  

Author(s):  
Khasan Nasriddinov ◽  
Ji-Eun Min ◽  
Hae-Gu Park ◽  
Seung Ju Han ◽  
Jingyu Chen ◽  
...  

Direct CO2 hydrogenation to long-chain hydrocarbons can mitigate global warming by extensively replacing fossil fuels. However, designing a suitable catalyst with high catalytic activity and C5+ hydrocarbon selectivity continues to...


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