Ignition delay time measurements behind reflected shock waves for a representative coal-derived syngas with and without NH_3 and H_2S impurities

摘要

Ignition delay times have been measured behind reflected shock waves for a syngas determined by averaging 40 coal syngas compositions from the literature. The average mixture (0.4554% CO/0.3297% H_2/0.1032% CO_2/0.0172% CH_4/0.2407% H_2O/0.8538% O_2 in 98% Ar (mol.%)) was investigated at an equivalence ratio of 0.5 and at around 1.7, 13, and 32 atm. The same mixture was also investigated with impurities (200 ppm of NH_3 and 50 ppm of H_2S) whereas the effect of the various constituents was studied by comparing results from a baseline mixture (H_2/CO/O_2/Ar) and results with this baseline mixture with only one of the other constituents. Direct measurements of the water vapor mole fractions were performed using a tunable diode laser absorption diagnostic near 1.38 μm. Results showed that extending the mixture composition to include realistic concentrations of species beyond just the CO and H_2 does not have a very large effect on the ignition delay time under the conditions from this study. However, a comparison of this coal-derived syngas with a syngas derived from biomass, tested in an earlier study, exhibited larger differences due to the difference in the CH_4 concentration. Experimental data were compared with recent detailed kinetics mechanisms from the literature.