Relation of Adiabatic Flame Temperature with the Type of Hydrocarbons

Abstract

The relationship between adiabatic flame temperature and of the concentration of products and the type of hydrocarbons in the stoichiometric reaction with air at constant pressure were studied with twenty seven hydrocarbons, by the aid of an electronic computer.The effect of the reaction pressure on the adiabatic flame temperature and the relationship between the burning velocity and the adiabatic flame temperature was discussed, as the temperature decreased by heat losses from the adiabatic condition.The reaction products were selected to be carbon dioxide, carbon monooxide, monoatomic carbon, water vapour, nitrogen monooxide, hydroxyl radical, molecule and atom of oxygen, of hydrogen, and of nitrogen. The pressure was in the range of 1∼50atm.Following results were obtained;(1) Adiabatic flame temperature of hydrocarbons shows a tendency to be in the range of 2, 280∼2, 300°K, as the heat release at the formation of the hydrocarbon increases.(2) Adiabatic flame temperature of hydrocarbons varies with the heat of combustion and with the mole numbers of the main products, namely, carbon dioxide, water vapour and nitrogen molecule. The parameter of the type of the hydrocarbon is given by the expression heat of combustion at 298°K/a0+0.25b0/0.21+0.25b0in which a0 and b0 is the number of carbon atoms of the hydrocarbon and of hydrogen atoms respectively.(3) Weight of carbon monooxide, nitrogen monooxide and gaseous carbon at the reaction of the unit weight of hydrocarbon increases with the adiabatic flame temperature.(4) Adiabatic flame temperature increases with reaction pressure, but the pressure has little effect on the adiabatic flame temperature when the pressure exceeds 20atm.(5) Burning velocity of stoichiometric hydrocarbon-air mixture increases with the adiabatic flame temperature.