The investigation of co2 effect on the characteristics of methane diffusion flame

Abstract

Investigating the effect of mixing carbon dioxide with CH4 has been in attention of many researchers. This is because alternative fuels such as bio syngas have high concentrations of carbon dioxide. However, biogas and bio syngas are produced from various sources and as a result the amount of methane with carbon dioxide varies depending on the production source. As a consequence combustion characteristics of these fuels vary and also tend to be less known with respect to that of natural gas. To have a better design for non-fossil fuel combustion system, a wider examination is required to understand the effect on the combustion properties by mixing carbon dioxide with methane. Image processing is utilised in this study to investigate the flame properties by digitally analysing the flame chemiluminescence emission. The images are captured by a high speed colour camera, which is able to record and monitor the spatial and temporal changes in flame chemiluminescence when adding different amounts of carbon dioxide to methane from the moment of ignition to any specific time during combustion. Results confirmed that by increasing carbon dioxide level, the flame temperature and soot level are reduced and the flame height is getting longer. On the other hand it has been qualitatively observed that the ignition time is increased. Also, the presence of soot that only emits infrared light is observed during the ignition period. Through digital image processing more quantitative analysis are carried out.