Nitrogen conversion

Fig. 9. Waste nitrogen conversion to NO as a function of the nitrogen content of the synthetic soHd waste where (D) represents aniline ( ), pyridine (0)>...

J.E. Fuel nitrogen conversion in solid fuel fired systems, Prog. Energy Combust. Sci., 29, 89-113, (2003). 

The formation of prompt NO increases the complexity of the nitrogen chemistry in gas flames considerably. This is illustrated in Fig. 14.9, which shows the most important reaction paths in prompt NO formation, as well as fuel nitrogen conversion—two mechanisms that share some common features. Prompt NO is, as the name indicates, a very rapid mechanism. The initiating step (R117) takes place in the flame zone, where methylidyne radicals (CH) may be formed in significant quantities. 

This flow is enriched in less tightly adsorbed components in the case of air separation, the product consists typically of 90 to 95 percent oxygen, with the balance argon and a small amount of nitrogen. Conversely the exhaust stream is somewhat depleted in oxygen and argon. 

Bacterial production from each food component is calculated by multiplying consumption by bacterial nitrogen conversion efficiencies, and these are then summed to calculate the total daily bacterial production. The faeces component of the model... 

Beer, J. M., Jacques, M. T., Farmayan, W., and Taylor, B. R., "Fuel-Nitrogen Conversion on Staged Combustion of a High Nitrogen Petroleum Fuel", pp 101-10, Eighteenth Symposium (International) on Combustion, The Combustion Institute, Pittsburgh, PA, 1981. 

BOUND NITROGEN AND/OR FUEL RICH NITROGEN CONVERSION... 

A Study ot Fuel Nitrogen Conversion in Jet-Stirred Combustors... 

Table I. Results from fuel nitrogen conversion experiments - isooctane fuel.

Table II. Combustor < > Results from fuel nitrogen conversion experiments - toluene fuel. t TFN NO hc soar (ms) / % of v, % ofv, vol. %v, % of v fuel N TFN" las CH fuel C ...

Data from the present set of experiments suggest that the conversion of fuel nitrogen to TFN in jet-stirred combustors depends upon the equivalence ratio and average residence time of gases within the combustor, the fuel type and certain physical characteristics of the combustors. However, the effects of these primary variables on fuel nitrogen conversion appear to be related to their effects on the concentrations of unburned hydrocarbons and soot in the exhaust gases. These effects and their relationships to unburned hydrocarbon and soot concentrations are discussed below. 

The pattern of increasing conversion for equivalence ratios richer than the hydrocarbon breakthrough equivalence ratio appeared to depend on the fuel, however. Figure 3 provides a comparison of fuel nitrogen conversion from isooctane and toluene at the richest equivalence ratios tested in the JSC. For both fuels, HC s increased as the equivalence ratio was increased from 1.6 to 1.8. Corresponding increases in fuel nitrogen conversion were found for isooctane mixtures at 3, 6 and 10 ms residence times, but toluene mixtures at these conditions produced either smaller increases or decreases in conversion with increasing... 

Any interaction between fuel nitrogen conversion and soot concentrations, however, may be peculiar to the mixture equivalence ratios. Data from the limited LFJSC experiments, which were obtained at relatively leaner equivalence ratios (< >=1.2,... 

JSC cases, an interaction between HCN and soot appears to be a possible explanation of the observed fuel-type effects on fuel nitrogen conversion in the JSC. 

The effects of residence time on fuel nitrogen conversion may... 

Comparisons of the results from the two different diameter JSC s at a residence time of 8 ms suggested that fuel nitrogen conversion was similar at the leaner equivalence ratios (<(>=1.2, 1.4), but at richer equivalence ratios fuel nitrogen conversion and HC concentrations were larger in the larger J SC (Figure 7). 

The observed differences among the data obtained at similar JSC and LFJSC operating conditions suggest that comparisons of data from the various combustors must allow for possible effects of combustor type in the results. Extensions of the results to larger, commercial size gas turbine combustors or to similar laboratory combustors should also be made with extreme caution. Qualitative trends such as the dependence of fuel nitrogen conversion on HC concentrations should be valid within a given combustor however, quantitative numerical results may depend strongly on specific combustor characteristics. For example,... 

This research was conducted for the U. S. Department of Energy as part of Contract No. DE-AC22-77ET11313. Funding for the fuel nitrogen conversion experiments was provided by Exxon Research and Engineering Company. 

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