scholarly journals Kinetics of elementary processes relevant to incipient soot formation. Final technical report

1998 ◽  
Author(s):  
M.C. Lin
Clay Minerals ◽  
1998 ◽  
Vol 33 (2) ◽  
pp. 269-276 ◽  
Author(s):  
P. Dion ◽  
J.-F. Alcover ◽  
F. Bergaya ◽  
A. Ortega ◽  
P. L. Llewellyn ◽  
...  

AbstractAlthough the kinetics of the dehydroxylation of kaolinite have been widely studied, there is no definitive explanation of its mechanism due to its dependence on a variety of parameters. In this study, the dehydroxylation of kaolinite has been studied using controlled-transformation rate thermal analysis (CRTA), allowing precise control of the reaction rate, and thus of both the temperature and pressure above the sample. Modelling of the experimental results obtained by CRTA as well as those from TEM and MAS-NMR show that two elementary processes (diffusion and firstorder) can occur in competition. At the start of the decomposition the diffusion mechanism is predominant, but as the reaction progresses, the first-order mechanism prevails. It would seem that the importance of each process depends, in particular, on the presence of defects as well as on the local vapour pressure.


2018 ◽  
Vol 140 (12) ◽  
Author(s):  
Richard Scenna ◽  
Ashwani K. Gupta

Previous works have demonstrated that the distributed reaction regime improved the reformate product distribution, prevented soot formation, and favored higher hydrogen yields. The experimental data from these works and additional literature focusing on individual reactions provided an insight into how the distributed reaction regime influenced the reformate product composition. The distributed reaction regime was achieved through the controlled entrainment of hot reactive products (containing heat, carbon dioxide, steam and reactive radicals and species) into the premixed fuel air mixture, elongating the chemical time and length scales. High velocity jets enhanced mixing, while shortening the time and length scales associated with transport. As some steam and carbon dioxide will form in the reforming process, it was theorized that the mixing of the entrained flow (containing heat, carbon dioxide, and steam) into the premixed fuel air mixture promoted dry and steam reforming reactions, improving conversion. The available information on chemical kinetics of reformation is rather limited. In this work, the activity and timescales of these reactions were determined from the available experimental data. This was then used to assess which reactions were active under Distributed Reforming conditions. These data help in the design and development of advanced reformers using distributed reforming conditions.


1998 ◽  
Vol 152 (4) ◽  
pp. 667-683 ◽  
Author(s):  
V. Kruzhanov ◽  
B. Stöckhert

Sign in / Sign up

Export Citation Format

Share Document