scholarly journals Reducing Reaction Temperature, Steam Requirements, and Coke Formation During Methane Steam Reforming Using Electric Fields: A Microkinetic Modeling and Experimental Study

ACS Catalysis ◽  
2017 ◽  
Vol 7 (10) ◽  
pp. 6957-6968 ◽  
Author(s):  
Fanglin Che ◽  
Jake T. Gray ◽  
Su Ha ◽  
Jean-Sabin McEwen
2010 ◽  
Vol 2010.15 (0) ◽  
pp. 393-394
Author(s):  
Kentaro Morimoto ◽  
Masato Hamano ◽  
Hiroshi Iwai ◽  
Motohiro Saito ◽  
Hideo Yoshida

2020 ◽  
Vol 9 (1) ◽  
pp. 80-89
Author(s):  
Juliana F. Gonçalves ◽  
Mariana M.V.M. Souza

Background: Hydrogen has been considered the energy source of the future and one of the processes for its production is the methane steam reforming. The catalyst used industrially is Ni/Al2O3 and the addition of promoter oxides can be an alternative to improve the performance of this catalyst, which suffers from coke formation and sintering. Objective: Evaluate the role of niobia on catalytic activity and stability. Methods: Ni/x%Nb2O5/Al2O3 (x = 5, 10 and 20) catalysts were synthesized via coprecipitation-wet impregnation method and characterized by X-ray fluorescence (XRF), N2 adsorption-desorption, X-ray diffraction (XRD), temperature- programmed reduction (TPR), temperature-programmed desorption of ammonia (TPD-NH3), etc. Finally, the catalysts were tested for methane steam reforming reaction. Results: All niobia-doped catalysts presented similar values of methane conversion and when comparing with Ni-Al, the addition of niobia slightly improved the methane conversion. In the stability test at 800oC, all doped and non-doped catalysts did not deactivate during the 24 h of reaction. Conclusion: The addition of 10 and 20 wt.% of niobia had a significant promoter effect over Ni/Al2O3 catalyst in terms of activity and stability at 800 oC and the sample with 20 wt.% of niobia presented lower coke formation.


Author(s):  
Qian Liu ◽  
Hongtao Zheng ◽  
Fumin Pan ◽  
Gang Pan ◽  
Ren Yang

Plasma is proposed as a prospective tool for chemical heat recovery process without restriction from reaction temperature. The author designed DBD catalytic reactors and carried out extensive experiments to investigate methane conversion and products yield and analyze the effect laws of steam to methane ratio, resident time and reaction temperature on methane steam reforming (MSR). Based on extensive experimental studies of steam reforming, a detailed reaction mechanism for the plasma-assisted MSR was developed and evaluated by comparison of experimentally derived and numerically predicted conversion and products yield. The comparisons showed the kinetic model well predicted methane conversion and products yield in different operating conditions. By employing the kinetic model and path flux analysis module the kinetic effects of low temperature non-equilibrium plasma assisted CH4 steam reforming on the methane conversion was studied without catalyst. The results showed that CH3 recombination was the limiting reaction for CO production; meantime O was the critical species for CO production. By adding Ni catalyst can reduce methyl recombination and promote hydroxyl into oxygen, which is beneficial to heat recovery. The proposed research ensures the effect laws and characters of MSR by plasma, and contribute to improve the objective products concentration and furthermore the energy efficiency.


Author(s):  
Marjan Alavi ◽  
Reza Eslamloueyan ◽  
Mohammad Reza Rahimpour

AbstractSteam reforming of methane (SRM) is an important stage of hydrogen production. Using a membrane reactor (MR) to separate the produced H2positively affects CH4conversion by shifting the equilibrium. This H2removal increases the risk of coke formation in the process. In this study, the influence of different parameters such as Damkohler’s number (Da) and permeation number (θ) on CH4conversion and H2recovery are investigated. In order to find the optimum condition for this MR in which CH4conversion, H2Recovery are maximized and the risk of coke formation is minimized, the elitist non-dominated sorting genetic algorithm (NSGA-II) is employed to achieve the Pareto front in a three objective space. The single optimal solution is selected from Pareto front by TOPSIS decision making method. In the optimized condition methane conversion and hydrogen recovery are improved about 19.8% an 6.8%, respectively. Also, the risk of coke formation in the MR is reduced.


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