scholarly journals A Novel Study of Methane-Rich Gas Reforming to Syngas and Its Kinetics over Semicoke Catalyst

2014 ◽  
Vol 2014 ◽  
pp. 1-6
Author(s):  
Guojie Zhang ◽  
Aiting Su ◽  
Jiangwen Qu ◽  
Yannian Du

A small-size gasification unit is improved through process optimization to simulate industrial United Gas Improvement Company gasification. It finds that the reaction temperature has important impacts on semicoke catalyzed methane gas mixture. The addition of water vapor can enhance the catalytic activity of reforming, which is due to the fact that addition of water vapor not only removes carbon deposit produced in the reforming and gasification reaction processes, but also participates in gasification reaction with semicoke to generate some active oxygen-containing functional groups. The active oxygen-containing functional groups provide active sites for carbon dioxide reforming of methane, promoting the reforming reaction. It also finds that the addition of different proportions of methane-rich gas can yield synthesis gas with different H2/CO ratio. The kinetics study shows that the semicoke can reduce the activation energy of the reforming reaction and promote the occurrence of the reforming reaction. The kinetics model of methane reforming under the conditions of steam gasification over semicoke is as follows:k-=5.02×103·pCH40.71·pH20.26·exp(−74200/RT).

2011 ◽  
Vol 324 ◽  
pp. 149-152
Author(s):  
Carlos Youssef ◽  
Eric Puzenat ◽  
Samir Najm ◽  
Nicole Jaffrezic-Renault ◽  
Chantal Guillard

TiO2P25 catalyst was used to study the photocatalytic oxidation of CO to CO2at 288K. Two parameters, O2and H2O were used to study its effect on the photocatalytic process. The dependency of the reaction rate on the CO concentration and water vapor was explained in terms of Langmuir-Hinshelwood mechanism. The presence of a high concentration of water vapor inhibits the CO photocatalytic oxidation at low oxygen concentration. We have noted an adsorption competition between CO and H2O on the TiO2active sites.


Author(s):  
Monem Alyaser ◽  
Rory Monaghan ◽  
Abdlmonem Beitelmal ◽  
Drazen Fabris

This paper introduces a novel gasification reactor that uses steam gasification of carbonaceous feedstock by indirectly heating the reacting flow through a high temperature heat exchanger without the need for partial combustion with oxygen. It demonstrates the importance of gasification as a method for increasing power plant efficiency and reducing emissions. This paper also describes the computational model created to model this novel gasifier and the results of the model that illustrates the efficiency and purity advantages of the new gasifier. The reactor was modeled as a 1D counter-reacting flows heat exchanger, using the effectiveness-number of transfer units (ε-Ntu) method. The heating flow was assumed to be fully combusted at the inlet. The gasification stream was modeled as a plug flow, where the reaction is kinetically controlled. A simplified version of the Random Pore Model (RPM) was used to predict the char consumption. The results indicate that the gasification of coal with steam without partial combustion with oxygen using this new concept is feasible. The gasification reaction rates are found to be slow at temperatures less than 1200°C, but most of the char conversion, which reached about almost 100% completion, occurred at higher than 1200°C.


2020 ◽  
Vol 8 (17) ◽  
pp. 8575-8585 ◽  
Author(s):  
Junming Luo ◽  
Xiaochang Qiao ◽  
Jutao Jin ◽  
Xinlong Tian ◽  
Hongbo Fan ◽  
...  

The potential of CrN as highly active ORR catalyst can be unlocked by enhancing its conductivity, enriching its d electrons and enlarging the exposure of active sites.


2016 ◽  
Vol 120 (14) ◽  
pp. 7705-7714 ◽  
Author(s):  
Beomgyun Jeong ◽  
Dongyoon Shin ◽  
Myounghoon Choun ◽  
Sandip Maurya ◽  
Jaeyoon Baik ◽  
...  

2017 ◽  
Vol 139 (6) ◽  
Author(s):  
Handong Wu ◽  
Sheng Li ◽  
Lin Gao

Gasification is the core unit of coal-based production systems and is also the site where one of the largest exergy destruction occurs. This paper reveals the exergy destruction mechanism of carbon gasification through a combined analysis of the kinetic method and the energy utilization diagram (EUD). Instead of a lumped exergy destruction using the traditional “black-box” and other models, the role of each reaction in carbon gasification is revealed. The results show that the exergy destruction caused by chemical reactions accounts for 86.3% of the entire carbon gasification process. Furthermore, approximately 90.3% of exergy destruction of chemical reactions is caused by the exothermal carbon partial oxidation reaction (reaction 1), 6.0% is caused by the carbon dioxide gasification reaction (reaction 2), 2.4% is caused by the steam gasification reaction (reaction 3), and 1.3% is caused by other reactions under the base condition. With increasing O2 content α and decreasing steam content β, the proportion of exergy destruction from reaction 1 decreases due to the higher gasification temperature (a higher energy level of energy acceptor in EUD), while the proportions of other reactions increase. This shows that the chemical efficiency is optimal when the extent of reactions 1 and 3 is equal and the shift reaction extent approaches zero at the same time.


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