scholarly journals An in depth investigation of deactivation through carbon formation during the biogas dry reforming reaction for Ni supported on modified with CeO2 and La2O3 zirconia catalysts

2018 ◽  
Vol 43 (41) ◽  
pp. 18955-18976 ◽  
Author(s):  
N.D. Charisiou ◽  
G. Siakavelas ◽  
L. Tzounis ◽  
V. Sebastian ◽  
A. Monzon ◽  
...  
2017 ◽  
Vol 7 (22) ◽  
pp. 5422-5434 ◽  
Author(s):  
Michalis A. Vasiliades ◽  
Petar Djinović ◽  
Albin Pintar ◽  
Janez Kovač ◽  
Angelos M. Efstathiou

The kinetic rate of inactive and active carbon formation in DRM over CeZrO2-supported NiCo alloy particles depends on the support's oxygen mobility.


2020 ◽  
Vol 594 ◽  
pp. 117439 ◽  
Author(s):  
Yaqian Wei ◽  
Xiu Liu ◽  
Noura Haidar ◽  
Hervé Jobic ◽  
Sébastien Paul ◽  
...  

Author(s):  
McKenzie P. Kohn ◽  
Marco J. Castaldi ◽  
Robert J. Farrauto

Landfills are the second-largest source of anthropogenic methane emissions in the U.S., accounting for 22% of CH4 emissions. Landfill gas (LFG) is primarily composed of CH4 and CO2, and currently only 18% of this is used for energy. Because landfills will continue to be used for the foreseeable future, complete utilization of LFG is becoming more important as the demand for energy increases. Catalytically reforming LFG produces syngas (H2 and CO) that can be converted to liquid fuels or mixed into the LFG stream to produce a more reactive, cleaner burning fuel. It has been demonstrated that injecting 5% syngas into a simulated LFG mixture prior to engine combustion decreases CO, UHC, and NOx emissions by 73%, 89%, and 38%, respectively. One barrier to using LFG in a catalytic system is the contaminant content of the LFG, including chlorine and sulfur compounds, higher order hydrocarbons, and siloxanes that have the potential to poison a catalyst. Chlorinated compounds are present in LFG at 10–100ppm levels and are often found as chlorocarbons. This research explores the effect of methyl chloride on the activity of a Rh/γ-Al2O3 catalyst while dry reforming LFG to syngas. It has been found that methyl chloride acts as a reversible poison on the dry reforming reaction, causing a loss in dry reforming activity, decrease in syngas production, and increase in H2/CO ratio while CH3Cl is present in the feed. CH3Cl exposure also decreases the acidity of the catalyst which decreases carbon formation and deactivation due to coking.


Chemistry ◽  
2018 ◽  
Vol 1 (1) ◽  
pp. 3-16 ◽  
Author(s):  
Cameron Price ◽  
Emily Earles ◽  
Laura Pastor-Pérez ◽  
Jian Liu ◽  
Tomas Reina

Encapsulation of metal nanoparticles is a leading technique used to inhibit the main deactivation mechanisms in dry reforming of methane reaction (DRM): Carbon formation and Sintering. Ni catalysts (15%) supported on alumina (Al2O3) and ceria (CeO2) have shown they are no exception to this analysis. The alumina supported catalysts experienced graphitic carbonaceous deposits, whilst the ceria showed considerable sintering over 15 h of DRM reaction. The effect of encapsulation compared to that of the performance of uncoated catalysts for DRM reaction has been examined at different temperatures, before conducting longer stability tests. The encapsulation of Ni/ZnO cores in silica (SiO2) leads to advantageous conversion of both CO2 and CH4 at high temperatures compared to its uncoated alternatives. This work showcases the significance of the encapsulation process and its overall effects on the catalytic performance in chemical CO2 recycling via DRM.


2022 ◽  
Vol 57 ◽  
pp. 101880
Author(s):  
Renata O. da Fonseca ◽  
Antonella R. Ponseggi ◽  
Raimundo C. Rabelo-Neto ◽  
Rita C.C. Simões ◽  
Lisiane V. Mattos ◽  
...  

Catalysts ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 481 ◽  
Author(s):  
Anand Kumar

Methane dry reforming (MDR) is an attractive alternative to methane steam reforming for hydrogen production with low harmful environmental emissions on account of utilizing carbon dioxide in the feed. However, carbon formation in the product stream has been the most challenging aspect of MDR, as it leads to catalyst deactivation by coking, prevalent in hydrocarbon reforming reactions. Common strategies to limit coking have mainly targeted catalyst modifications, such as by doping with rare earth metals, supporting on refractory oxides, adding oxygen/steam in the feed, or operating at reaction conditions (e.g., higher temperature), where carbon formation is thermodynamically restrained. These methods do help in suppressing carbon formation; nonetheless, to a large extent, catalyst activity and product selectivity are also adversely affected. In this study, the effect of ammonia addition in MDR feed on carbon suppression is presented. Based on a thermodynamic equilibrium analysis, the most significant observation of ammonia addition is towards low temperature carbon dioxide activation to methane, along with carbon removal. Results indicate that ammonia not only helps in removing carbon formation, but also greatly enriches hydrogen production.


Sign in / Sign up

Export Citation Format

Share Document