Experimental and modeling study of water time histories during H 2 S-N 2 O combustion in a shock tube

With the interest in directly burning sour gas in gas turbines, and the fact that even small amounts of H 2 S or its combustion products can alter combustion characteristics, many research studies have been performed to better understand the combustion chemistry of H2S. In the present study, the water formation was followed by laser absorption with N2O as an oxidant, instead of O 2 . Nitrous Oxide being essentially consumed via N2O ( + M) ⠂N2 + O ( + M), the water formation via the H2S + O route can then be probed to further validate the models. Three H2S/N2O mixtures diluted in 98% Ar were studied to cover the following range of equivalence ratios: 0.5, 1.0, and 2.0, over a wide range of temperatures (1580-1940 K) around atmospheric pressure. A chemical kinetic model was then developed first by validating the base N2O kinetics mechanism, then by investigating the experimental results presented herein. The N2O kinetics mechanism was updated with recent work on the low-and high-pressure limits for N2O decomposition (N2O ( + M) ⠂N2 + O ( + M)) as well as a review of rate coefficients for N2O + H ⠂N2 + OH from the literature. Good agreement is shown for H2/N2O mixtures. Updates were then made to the H2S kinetics mechanism, specifically, an update from the literature on SO2 + H ( + M) ⠂SO + OH ( + M) and an adjustment to SO + SH ⠂S2 + OH. Additionally, reactions between SH and N2O were determined using W1BD data and transition state theory which required the addition of an NNS sub-mechanism. With these updates, the mechanism provides good agreement with the H2S/N2O experiments.& COPY; 2022 The Combustion Institute. Published by Elsevier Inc. All rights reserved.