| Abstract [eng] |
Methane has at least 25 times more impact on climate change than CO2. Around three-quarters of atmospheric methane pollution is produced by landfills and livestock. The rest are related to anthropogenic activity, i.e., industry, etc. Due to the dependence of natural biological degradation processes on seasonal and daily conditions, the emitted CH4 concentrations from these sources are unstable. In general, if biogas contains less than 30% of CH4 content, it is considered incombustible because of the low calorific value and emitted into the atmosphere. Previous studies showed that the unique design of a small swirl gas burner assisted with gliding arc plasma could increase the calorific value of biogas approximately four times and maintain stable combustion. The authors conducted complex research on the combustion of low calorific value biogas (CH4/CO2) mixtures at different air excesses, oxidising agent composition (O2/N2 - O2/Ar) and the influence of plasma assistance. The spectrometric characteristics of the flame (luminescence wavelengths) at different flame heights were analysed simultaneously by determining the composition of combustion gaseous products (O2, CO, NOx, NO, and NO2). Plasma-assisted combustion with nitrogen-containing air generates high intensities of active radicals, i.e., OH*, O*, NH*, and C2* excitation spectra peaks concentrated near plasma. It was investigated that plasma assistance, air excess and composition significantly influence the formation of radicals and the composition of combustion products. It was proven that the combustion of biogas containing less than 30% CH4 can be used for energy production under plasma-assisted combustion conditions. |
