Comparison of the Maximum Gas Combustion Pressure of Hydrogen/Oxygen/Nitrogen-between Chemical Equilibrium Calculations and Experimental Data

A study was completed comparing equilibrium combustion pressures obtained using constant volume and internal energy constraints to maximum combustion pressures from an existing experimental data base for hydrogen / oxygen and nitrogen mixtures (Jo and Crowl, 2006). We found that the experimental and calculated combustion pressures were close near the stoichiometric combustion point. At other compositions, particularly near the flammable limits, the calculated equilibrium pressures were much higher. Since the maximum pressure is of interest in insuring the design of process equipment and vents, the equilibrium calculation approach can be used instead of experimental data.