scholarly journals The Influence of the Distributed Reaction Regime on Fuel Reforming Conditions

2018 ◽  
Vol 140 (12) ◽  
Author(s):  
Richard Scenna ◽  
Ashwani K. Gupta
Keyword(s):  
Experimental Data ◽  
Carbon Dioxide ◽  
Soot Formation ◽  
Product Distribution ◽  
Fuel Reforming ◽  
Length Scales ◽  
Reaction Regime ◽  
Available Information ◽  
Kinetics Of ◽  
Reforming Reactions

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.

OXIDATION MECHANISM OF THE BUTADIYNYL RADICAL, C4H: ANALOGUE OF C2H OR NOT?

2013 ◽  
Vol 12 (06) ◽  
pp. 1340002
Author(s):  
WEI-WEI ZHU ◽  
SHAO-WEN ZHANG ◽  
YI-HONG DING
Keyword(s):  
Atomic Oxygen ◽  
Energy Surface ◽  
Soot Formation ◽  
Oxidation Mechanism ◽  
Carbon Chain ◽  
Exchange Product ◽  
Ethynyl Radical ◽  
Kinetics Of ◽  
Oxygen Conversion ◽  
Recent Attention

Reactions of the carbon-chain radicals are of great importance in the combustion and astrophysical processes. The kinetics of the butadiynyl radical, C 4 H , has received recent attention. While there has been sufficient knowledge concerning the oxidation of the ethynyl radical, C 2 H , oxidation of the higher even-numbered members C 2n H (n > 1) is hardly known. In this paper, to enrich the C 4 H -chemistry, we report the first study of the oxidation mechanism of C 4 H . At the CCSD(T)/aug-cc-pVTZ//B3LYP/6-311++G(d,p)+ZPVE level, the potential energy surface (PES) survey is presented covering various product channels P1( CO + HC 3 O ) (-152.7 kcal/mol), P2( C 3 H + CO 2) (-117.9), P3( HCO + C 3 O ) (-108.5), P4( HC 4 O +3 O ) (-45.2), and P5( OH + C 4 O ) (-33.2) accompanied by the master equation rate constant calculations. Despite the similarity in the PES, the kinetics of C 4 H +3 O 2 differs dramatically from that of the analogous C 2 H +3 O 2 reaction. For the C 4 H +3 O 2 reaction, the O -abstraction product P4( HC 4 O +3 O ) is almost the exclusive product, whereas the lowest C , O -exchange product P1( CO + HC 3 O ) and other products have little importance. By contrast, the C 2 H +3 O 2 reaction favors the C , O -exchange product HCO + CO . Being overall barrierless and mainly associated with the molecular → atomic oxygen conversion, the C 4 H +3 O 2 reaction should play an important role in the soot formation and interstellar chemistry where C 4 H is involved.

REACTIONS OF TRANSFORMATION OF THE FIVE-MEMBERED RING OF CYCLOPENTAPHENANTHRENE UPON INTERACTION WITH ACETYLENE: A THEORETICAL STUDY

2020 ◽  
Author(s):  
A. S. Semenikhin ◽  
◽  
A. S. Savchenkova ◽  
I. V. Chechet ◽  
S. G. Matveev ◽  
...  
Keyword(s):  
Aromatic Hydrocarbons ◽  
Theoretical Study ◽  
Narrow Range ◽  
Soot Formation ◽  
Initial Conditions ◽  
Experimental Studies ◽  
Membered Ring ◽  
Combustion Chambers ◽  
Polycyclic Aromatic ◽  
Kinetics Of

Reducing emissions of carcinogenic polycyclic aromatic hydrocarbons (PAHs) and the smoke number at the stage of designing and improving of combustion chambers is an urgent engineering and environmental task that requires improvement of the currently used predictive combustion models. The submechanisms describing the growth of PAHs in such models are incomplete and valid only in a narrow range of initial conditions. Further refinement of the kinetics of PAH and soot formation is associated with the need for more theoretical and experimental studies.

Combustion kinetics of soot formation from toluene

1981 ◽  
Vol 18 (1) ◽  
pp. 1149-1158 ◽  
Author(s):  
T.S. Wang ◽  
R.A. Matula ◽  
R.C. Farmer
Keyword(s):  
Soot Formation ◽  
Combustion Kinetics ◽  
Kinetics Of

Kinetics of soot formation in tetrachloromethane pyrolysis

2000 ◽  
Vol 41 (3) ◽  
pp. 366-376 ◽  
Author(s):  
I. V. Zhil’tsova ◽  
I. S. Zaslonko ◽  
Yu. K. Karasevich ◽  
H. Gg. Wagner
Keyword(s):  
Soot Formation ◽  
Kinetics Of

Direct observations of radiation-enhanced transformations in glass

1983 ◽  
Vol 41 ◽  
pp. 354-355
Author(s):  
J. F. DeNatale ◽  
D. G. Howitt
Keyword(s):  
Glass Matrix ◽  
Diffusion Mechanism ◽  
Bubble Formation ◽  
Silicate Glasses ◽  
Phase Decomposition ◽  
Direct Observations ◽  
Thin Foils ◽  
Oxygen Bubble ◽  
Electron Energy Loss ◽  
Kinetics Of

The electron irradiation of silicate glasses containing metal cations produces various types of phase separation and decomposition which includes oxygen bubble formation at intermediate temperatures figure I. The kinetics of bubble formation are too rapid to be accounted for by oxygen diffusion but the behavior is consistent with a cation diffusion mechanism if the amount of oxygen in the bubble is not significantly different from that in the same volume of silicate glass. The formation of oxygen bubbles is often accompanied by precipitation of crystalline phases and/or amorphous phase decomposition in the regions between the bubbles and the detection of differences in oxygen concentration between the bubble and matrix by electron energy loss spectroscopy cannot be discerned (figure 2) even when the bubble occupies the majority of the foil depth.The oxygen bubbles are stable, even in the thin foils, months after irradiation and if van der Waals behavior of the interior gas is assumed an oxygen pressure of about 4000 atmospheres must be sustained for a 100 bubble if the surface tension with the glass matrix is to balance against it at intermediate temperatures.

Irradiation behavior of pyrolytic silicon carbide

1983 ◽  
Vol 41 ◽  
pp. 72-73
Author(s):  
R. J. Lauf
Keyword(s):  
Silicon Carbide ◽  
Fission Products ◽  
Thermodynamics And Kinetics ◽  
Neutron Fluences ◽  
Fuel Particles ◽  
Sic Coatings ◽  
Irradiation Behavior ◽  
Kinetics Of ◽  
Htgr Fuel

Fuel particles for the High-Temperature Gas-Cooled Reactor (HTGR) contain a layer of pyrolytic silicon carbide to act as a miniature pressure vessel and primary fission product barrier. Optimization of the SiC with respect to fuel performance involves four areas of study: (a) characterization of as-deposited SiC coatings; (b) thermodynamics and kinetics of chemical reactions between SiC and fission products; (c) irradiation behavior of SiC in the absence of fission products; and (d) combined effects of irradiation and fission products. This paper reports the behavior of SiC deposited on inert microspheres and irradiated to fast neutron fluences typical of HTGR fuel at end-of-life.

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