ABSTRACT
New recommendations for the heating values of components of natural gas are reported. These are based on a reassessment of the available experimental data. The new recommendations are valid for the temperature range from 0° to 25°C and for pressures up to about one atmosphere. For direct calorimetric measurements, it is also necessary to know the heating values of the major components of natural gas, although the dependence is indirect. The data for the isomers of n-hexane introduce additional complications. Enthalpies of combustion which have only been measured relative to n-hexane and only for the liquids. A generalization from the numbers is that the heating values are known only to 0.02 to 0.04 percent, with methane being the least well known. Any need for more accurate values will have to be met by a new measurement program, with new or improved techniques for burning the hydrocarbons.
