Enhancing Gas Burner Efficiency and Reducing Exhaust Emissions: An Experimental Study on the Use of Nebulized Carbon Nanoparticles

Natural gas (NG) is a significant source that burns into cleaner exhaust gases than other fossil fuels when used in combustion chambers, making it an environmentally friendly fossil fuel with a lower radiation heat transfer from the flame than many other liquid and solid fuels. This study involved an experiment to examine the impact of injecting nebulized carbon nanoparticles into an NG diffusion flame on the radiation characteristics and pollutant emissions of the NG. The experimental measurements were conducted using an industrial three-pass fire-tube steel boiler with a maximum capacity of 120 kW. Aiming to improve thermal efficiency and decrease environmental pollutants, a water-based nanofluid containing carbon nanoparticles (NPs) at 1000 ppm was prepared and injected, through the nebulization technology, into an NG burner at a mass flow rate of 5.5 g/min. Flame radiation heat flux was measured using an HFS01 water-cooled heat flux sensor. The findings indicate that the variations in flame properties (e.g., brightness and heat radiation) can be identified based on the infrared wavelengths emitted from the flame and water temperature variations (2 °C increase) at the boiler outlet. Injecting NPs also lowered the chimney gas temperature while enhancing the radiation heat flux by 5%. Despite a slight decrease in the average flame temperature, this technique successfully reduced thermal NOx and carbon monoxide (CO) emissions by 8 and 9 mg/kWh, respectively, as detected by a Testo 350 XL gas analyzer. This research underscores the potential benefits of using carbon NP injection to enhance burner efficiency and reduce the environmental impact of NG combustion.