| OCR Text |
Show of SRC-II MD, is expected to be decomposed rapidly during combustion, so its reaction process is formulated using an infinite rate reaction to form hydrogen cyanide and ethylene. Ethylene is formed instead of acetylene because of the aliphatic character of the heterocyclic compound. - Evaluation of this kinetics model requires detailed data for SRC-II MD and No. 2 fuel oil combustion which at present do not exist. However, by using the kinetics model that has been developed in this work in the context of a well-stirred reactor computation, the predicted combustion performance of SRC-II MD and No. 2 fuel oil can be compared to that experimentally determined for toluene and isooctane, and the trends indicated by this comparison can be evaluated in light of the available experimental data. For example, Fig. 9 provides a comparison of steady state stirred-reactor temperature predictions for SRC-II MD and No. 2 fuel oil, compared to experimental data and model predictions for toluene and isooctane, as a function of equivalence ratio. All computations of course assume the same residence time, pressure, and reactant initial temperatures. Both SRC-II MD and No. 2 fuel oil are predicted to show the same high equivalence ratio temperature variation as toluene, reflecting the preponderance of aromatic fuel components in their formulation. Results for CO, C0«, FU, FLO, and unburned hydrocarbon product species concentrations for both SRC-II MD and No. 2 fuel oil combustion are all similar to those obtained with toluene, with some detail differences reflecting the differences in fuel composition. However, the basic behavior of both fuels with respect to these combustion parameters is quite similar. On the other hand. SRC-II MD is expected to release considerably greater emissions of NO and HCN than No. 2 fuel oil because of its fuel-bound nitrogen content. Fig. 10 shows results for NO and HCN emissions from SRC-II MD computed using the quasiglobal kinetics model described in this paper. These results are compared with experimental data for isooctane doped with 1% by weight of pyridine. The agreement is quite good. Since the weight percentage of fuel-bound nitrogen in SRC-II MD is 0.86%, which is close to the level of pyridine doped in isooctane, it can be concluded that most of the NO and HCN emissions from SRC-II MD are predicted to arise from the fuel-bound nitrogen. Predicted sooting tendencies for No. 2 fuel oil and SRC-II MD are shown in Fig. IT. Both SRC-II MD and No. 2 fuel oil are predicted to soot much less than toluene. This is in agreement with results drawn from an industrial -burner test (Ref. 12) that SRC-II fuel oil produced no significant smoking tendencies. Fig. 11 also shows that the soot emissions predicted for SRC-II are higher when both aromatic fuel components are treated as precursors than when only methylethylnaphthalene 1.2.26 |
