Laminar axisymmetric syngas-air, syngas-methane mixture-air and biogas-air diffusion fames were studied over the pressure range of 5 to 20 atm to investigate the effect of pressure and dilution on soot formation. Spectral soot emission (SSE) optical diagnostic technique was used to measure the soot volume fraction and soot temperature in these flames. The fuel matrix consisted of three syngas fuels, two syngas-methane mixtures and two biogas fuels. In general, soot formation in syngas-methane mixtures and biogas diffusion flames showed strong pressure dependence at lower pressures but this dependence got weaker at elevated pressures. No soot was detected by SSE diagnostic technique in syngas-air flames at all pressures. The suppressive effect of carbon dioxide on soot formation prevailed at all pressures in syngas-methane mixtures and biogas flames.

Laminar axisymmetric syngas-air, syngas-methane mixture-air and biogas-air diffusion fames were studied over the pressure range of 5 to 20 atm to investigate the effect of pressure and dilution on soot formation. Spectral soot emission (SSE) optical diagnostic technique was used to measure the soot volume fraction and soot temperature in these flames. The fuel matrix consisted of three syngas fuels, two syngas-methane mixtures and two biogas fuels. In general, soot formation in syngas-methane mixtures and biogas diffusion flames showed strong pressure dependence at lower pressures but this dependence got weaker at elevated pressures. No soot was detected by SSE diagnostic technique in syngas-air flames at all pressures. The suppressive effect of carbon dioxide on soot formation prevailed at all pressures in syngas-methane mixtures and biogas flames.