Abstract
Natural gas is a significant energy source that burns more cleanly than other fossil fuels when used in combustion chamber. Although it is the most environmentally friendly fossil fuel, the radiation heat transfer of its flame is lower than that of liquid and solid fuels, where radiation remains an important factor in heat transfer. This study involved an experiment to examine the impact of injecting nebulized carbon nanoparticles into a natural gas diffusion flame on the radiation characteristics and pollutant emissions of natural gas. The experiments and measurements were conducted by using a three-pass fire tube industrial steel boiler with a maximum capacity of 120 kW. A novel aspect of our experiment was the use of nebulizer technology to inject 1000 ppm of carbon nanoparticles at a mass flow rate of 5.5 g/min into natural gas burners, aiming to improve thermal efficiency and decrease environmental pollutants. Flame radiation heat flux and luminosity were measured using an HFS01 water-cooled heat flux sensor and a TES-1332A digital luminance meter, respectively. The findings indicate that changes in flame properties, such as brightness and heat radiation, are linked to the infrared wavelengths emitted from the flame, as well as to a 2-degree Celsius increase in water temperature at the boiler outlet. Injecting nanoparticles also lowers the chimney gas temperature while enhancing the radiation heat flux by 5%. Despite a slight decrease in the average flame temperature, this technique successfully reduces thermal NOx emissions by 8% and carbon monoxide emissions by 9%, as detected by a Testo 350 XL gas analyzer. It is important to note that this research underscores the potential benefits of using carbon nanoparticle injection to enhance burner efficiency and reduce the environmental impact of natural gas combustion.