Farshad Farahbod - Department of Chemistry, Firoozabad Branch, Islamic Azad University, Firoozabad, Fars, Iran.
Narges Bagheri - Department of Chemistry, Firoozabad Branch, Islamic Azad University, Firoozabad, Fars, Iran.
Shoaib Memar bashi - Department of Chemistry, Firoozabad Branch, Islamic Azad University, Firoozabad, Fars, Iran.

The effect of oxygen concentration on performance of combustion process with basic fuels such asmethane, ethane and propane is evaluated in this paper. Different concentrations of oxygen areprovided by membrane and injected in to combustion chamber. The flame temperature, combustionthermal efficiency, x NO emissions in different torques, the amount of exhaust unburned carbon andthe amount of saved fuel gas are investigated in different oxygen concentration. Also, the molefraction of exhaust basics such as; 2 O ,OH , 2 H , H , O and 2 HO from combustion chamber aremeasured for precious evaluation of this process. In addition, the effluent side components suchas; N O 2 , N , HCO , 2 NH , 3 NH and HCN are surveyed in this paper. Experiments show that thehighest flame temperature is caused by Propane burning in 60% oxygen concentration however thisphenomenon produces higher thermal x NO . Also, the highest thermal efficiency is about 38.3% byburning methane fuel in 21% oxygen volume percentage. Experiments indicate that there is anoptimum amount of engine speed accompanied with oxygen concentration to increase the thermalefficiency and decrease the amount of unburned carbon. Obtained results in this paper were used todetermine optimal control points in the burner design stage.

Membrane; Combustion; Temperature; Fuel Gas; Thermal Efficiency