2nd International E-Conference on Engineering, Technology and Management - ICETM 2020
Author(s) : NIKOLAY VASILIK
Experiments and computations were conducted on infrared radiant burner operated on natural gas/air mixtures. The burner had not porous media and consisted of plates (recuperative elements) of heat-resistant metal alloy (Fe base, Cr 25%, Al 6%) with high thermal conductivity. The height of the recuperative elements system varied from 18 mm to 70 mm. The Al2O3 coatings were tested and found effective for covering the surface of the recuperative elements in burners. The operating surface temperature of recuperative elements coated with aluminum oxide reached values of 1450Â°C. Stable combustion mode is implemented in the range of specific burning power (firing rate) values from 2.8 MW/m2 to 5.3 MW/m2 per unit area of the gas stream cross-section. The maximum power of the burner is 16 kW with a flow cross-section of 30 cm2. The concentration of nitrogen oxides in the combustion products is up to 14ppm, the concentration of carbon monoxide is up to 20 ppm with an excess air coefficient (air ratio) of 1.4. The combustion process of fuel mixtures with an oxidizer in an infrared burner, which allows to work at increased values of firing rate and maintain the values of concentrations of toxic components in the combustion products characteristic of traditional infrared burners, consists of two stages. The first stage is the ignition of the mixture by a heated surface. The second stage is the combustion of the mixture inside the channel between recuperative elements in the conditions of heat exchange with the walls with the correct intensity. Sustained operation of the infrared burner is ensured by: high thermal conductivity and heat resistance of the recuperative elements material, the conditions for stable ignition of the gas mixture by heated recuperative elements surface, geometrical parameters of the recuperative elements system, the value of flow velocity and the composition of the mixture.