Effect of Oxygen Concentration on Distributed Flame Regime

2017 ◽  
Author(s):  
Richard Scenna ◽  
Ashwani K. Gupta
Keyword(s):  
Carbon Monoxide ◽  
Oxygen Concentration ◽  
Chemical Reaction ◽  
Partial Oxidation ◽  
Product Distribution ◽  
Length Scales ◽  
Reaction Condition ◽  
Effect Of Oxygen ◽  
Reforming Reactions ◽  
Oxygen Concentrations

This work investigated the effect of oxygen concentrations in the reactor on the partial oxidation of JP8 under the distributed reaction condition. Reforming efficiency as high as 74% was achieved; syngas composition consisted of 20.7 to 22.3% hydrogen and 20.2 to 21.5% carbon monoxide. Reformate product distribution and quality was found to depend on the reactor oxygen concentrations and, to a lesser extent on flame regime. Previous works operating at similar conditions found that higher reformate quality was associated with the more distributed reactor conditions. An increase in reactor oxygen concentrations fostered a more rapid chemical reaction, which shortened chemical time and length scales. While this resulted in a less distributed reactor, the potential decrease in reformate quality was offset by the increased availability of oxygen. As the reactions were limited by the availability of oxygen, the addition of oxygen enhanced the extent of reforming reactions, to promote increased conversion and reforming efficiency.

Wet Partial Oxidation of JP8 in a Well-Insulated Reactor

2016 ◽  
Author(s):  
Richard Scenna ◽  
Ashwani K. Gupta
Keyword(s):  
Carbon Monoxide ◽  
Power Systems ◽  
Partial Oxidation ◽  
Soot Formation ◽  
Catalytic Reforming ◽  
High Sulfur Content ◽  
Reaction Regime ◽  
Reduced Costs ◽  
Direct Use ◽  
Reforming Reactions

This work investigates wet and dry non-catalytic partial oxidation of JP8 under distributed reaction regime condition. Previous works have demonstrated the potential of the distributed reaction regime to increase hydrogen and carbon monoxide production over conventional non-catalytic reforming and suppress soot formation inside the reactor. Jet propellant 8 (JP8) has a high sulfur content (up to 3000ppm) and a tendency to form coke, making it an ideal candidate for this non-catalytic approach. Experimental results are reported with the reactor operated at fixed oxygen to carbon ratio of 1.08 and steam to carbon ratios varied from 0.0 to 0.23. Numerical simulations were used to determine flame regime and extent of distribution. Steam provided favorable effects even with trace amounts (S/C=0.01), but more pronounced effects were observed at steam to carbon ratio of 0.17. Syngas composed of 22.5–24.6% hydrogen and 20.1–23.3% carbon monoxide was evolved. Of the hydrocarbons detected, only methane was seen in finite amounts (0.17–0.29%). The increase in performance in terms of reforming efficiency and conversion exceeded what can be ascribed to steam reforming reactions alone. Additional enhancement is attributed to distributed reaction in the reactor. Reforming efficiency of approximately 68–80% is comparable to that from catalytic reforming. Low steam to carbon ratio offers higher sustainability in mobile power systems at reduced costs from direct use of water recovered from fuel cells.

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.

Effect of Oxygen Concentration and pH on Electrode Potential of Stainless Steels and Operation of Microcouples

CORROSION ◽  
1966 ◽  
Vol 22 (1) ◽  
pp. 16-20 ◽  
Author(s):  
YU. M. KOROVIN ◽  
I B. ULANOVSKII
Keyword(s):  
Oxygen Concentration ◽  
Stainless Steels ◽  
Electrode Potential ◽  
Sea Water ◽  
Relative Effect ◽  
Solution Ph ◽  
Corrosion Rates ◽  
Electrode Potentials ◽  
Effect Of Oxygen ◽  
Oxygen Concentrations

Abstract Using Russian steels of 13 Cr and 18–9 analyses in general experiments are conducted varying pH and oxygen concentrations in sea water to determine the relative effect of these variables on corrosion rates in crevices. Effect of oxygen concentrations in the range 1–9 mg/1 and pH 8.3 to 2.3 are reported. Changes in pH were found to strongly and changes in oxygen concentration weakly influence the corrosion rate. Authors postulate that anodic passivity is effected after application of tenths of a milliampere per square centimeter whereas when the pH in the anodic space is lowered, critical current density required for passivation increases 40–50 fold. Heat treatment of the steel does not influence electrode potentials when solution pH is lowered.

Respiratory metabolism of Azotobacter vinelandii cells at oxygen concentrations that initially range from suboptimal to supraoptimal for nitrogenase activity

1991 ◽  
Vol 37 (4) ◽  
pp. 321-325 ◽  
Author(s):  
Jay B. Peterson
Keyword(s):  
Oxygen Uptake ◽  
Oxygen Concentration ◽  
Azotobacter Vinelandii ◽  
Nitrogenase Activity ◽  
Low Oxygen ◽  
Total Oxygen ◽  
Apparent Affinity ◽  
Lower Oxygen ◽  
Effect Of Oxygen ◽  
Oxygen Concentrations

The effects of three low oxygen concentrations on nitrogenase activity, total oxygen uptake, and respiratory parameters (Vmax and Ks(O2) of N2-grown Azotobacter vinelandii were studied in acetylene reduction assays during a 2-h incubation. The cell suspensions were taken from cultures grown at low aeration. Total oxygen uptake was higher with each increment in oxygen concentration. The highest oxygen concentration was initially supraoptimal for nitrogenase activity. The Ks(O2) values, representing the apparent affinity of the respiration system for oxygen, increased during the incubation of cells at the highest oxygen concentration. The Ks(O2) values at the two lower oxygen concentrations decreased and were very similar. A small effect of oxygen on the Vmax was observed. These results show that the metabolism determining the apparent affinity of the system for oxygen responds to the oxygen concentrations. Furthermore, this metabolism did not substantially increase the Ks(O2) unless the oxygen concentration was high enough to inhibit nitrogenase activity, indicating that the two processes may be linked. Key words: Azotobacter, oxygen regulation, nitrogen fixation.

scholarly journals EFFECT OF OXYGEN CONCENTRATION AND RELATIVE HUMIDITY ON THE RANCIDITY PROCESS OF WALNUTS AND PEANUTS

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 537b-537
Author(s):  
J.I. Maté ◽  
M.E. Saltveit ◽  
J.M. Krochta
Keyword(s):  
Relative Humidity ◽  
Oxygen Concentration ◽  
Salt Solutions ◽  
Persian Walnut ◽  
Peroxide Values ◽  
Roasting Process ◽  
Effect Of Oxygen ◽  
Oxygen Concentrations

Rancidity is a major problem during the storage of shelled peanuts and walnuts. Blanched peanuts, blanched dry roasted peanuts, blanched oil roasted peanuts (all of them extra large Virginia variety) and shelled Persian walnut (Chandler variety) were maintained in closed jars at 37 C. Relative humidity was controlled by saturated salt solutions at 20% and 55%. Oxygen concentration was 21% or reduced to 0.1% by flushing with nitrogen. Samples were taken every 2 weeks for 10 weeks. Peroxide values were measured and volatiles were analyzed to determine the rancidity of the samples. Oxygen concentrations in the jars and nut moisture were also measured. Dry roasted peanuts were the most susceptible to rancidity. Blanched peanuts, without any roasting process, were the most stable. The results quantified the importance of oxygen as a major factor in rancidity at the relative humidities studied. It was concluded that it is possible to quantitatively control the rancidity process by decreasing the oxygen concentration surrounding the nuts.

The reaction of CH3NO2 on O-covered Mo(110): the effect of oxygen on product distribution

2004 ◽  
Vol 555 (1-3) ◽  
pp. L127-L132 ◽  
Author(s):  
L.J. Deiner ◽  
A.S.Y. Chan ◽  
M.A. Sheehy ◽  
C.M. Friend
Keyword(s):  
Product Distribution ◽  
Effect Of Oxygen
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