Examination of combustion characteristics of oxygen enriched synthetic gases mixtures at various acoustic frequencies

ABS TRACT Synthetic gases attract the attention of researchers due to the increase in energy demand. H2 and CO gases are the main components of synthetic gases. In this study, three different gas mixtures were tested according to their H2/CO (3, 1.5, 0.5) ratios. Thermal power (3 kW), swirl number (1) and equivalence ratio (0.7) kept constants for all experiments. Three different oxygen ratios selected for the oxygen enrichment experiments. First, the gas mixture was burned with standard air. After that, the oxygen concentration in the oxidizer was raised to 23 % and 25 % for examining the effect of oxygen enrichment. The stability results showed that an increase of hydrogen content in the synthetic gas mixtures caused decreasing in the oxygen enrichment limit. The mixture, which can be enriched up to 25.8 % O2 while the H2/CO ratios are 0.5, can be increased up to 25.2 % O2 at a medium H2/ CO ratio (1.5). In the case where the H2/CO ratio was increased to the high level (3) by increasing the hydrogen level, the oxygen enrichment limit decreased to 24.1 %. A stable flame did not occur after these oxygen enrichment values. In addition, dynamic pressure data were recorded for all mixtures under external acoustic enforcement. Increases in the hydrogen and oxygen ratio at the same time caused the flame instabilities. Thus, the flame extinguished under acoustic enforcement. In addition to these results mentioned, the emission values showed that oxygen enrichment caused the decrease in CO emissions but the increase of NOx values for all synthetic gas mixtures.(c) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

This study investigated the effects of hydrogen content and oxygen enrichment on synthetic gas mixtures. The results showed that increasing hydrogen content decreased the oxygen enrichment limit and caused flame instabilities. Furthermore, oxygen enrichment resulted in reduced CO emissions but increased NOx values for all synthetic gas mixtures.