Experimental study of nebulized ethanol injection in radiative heat transfer and NOX pollutant of natural gas flame

Compared to liquid and solid fuels, natural gas produces much less soot during combustion, and the melting and reaction on the surface of these soot is one of the main factors in the production of radiation in the flame. The use of natural gas as a substitute for liquid fuel in industrial and household burners has caused a decrease in thermal efficiency due to the weak radiation bands of gas fuel, therefore the combustion of natural gas has a lower thermal efficiency compared to liquid and solid fuels. And improving the radiant heat transfer of natural gas flame is one of the main challenges of active researchers in this field. In this research, the ethanol fuel was reduced to micron size by the nebulizer and injected into the flame with turbulent flow and as a result, better mixing, and its effects on the radiant heat transfer of the flame as well as the reduction of NOX pollutant were investigated. The results of the present research show that the injection of 1 percent by weight of ethanol in a nebulized form causes a 1 percent increase in the average temperature of the natural gas flame along the length of the boiler and a 3.5 percent increase in the radiant heat transfer flux, and also the injection of micron ethanol particles causes the production of NOX pollutants to decrease by 12.5 percent.