Formulas and graphs for representing the interchangeability of fuel gases

Abstract

When gas-burning appliances have been adjusted to give satisfaction with a gas of one composition, and are then supplied with gas of a different composition, changes are usually noted in the characteristics of the flames produced. When no change can be seen or measured, the gases are said to be "exactly interchangeable". When undesirable changes do not occur to a greater extent than the person using the term thinks permissible, the gases are usually still called "interchangeable" with the omission of the adverb. No entirely satisfactory method has ever been found for predicting or representing the extent to which different gases depart from exact interchangeability. In this paper a set of six "indexes" is given for specifying and predicting from the composition of any two fuel gases the extent of the effects that occur when one is substituted for another. Four of these indexes are new. Their derivation is given, and their application is shown by comparison with the results of extensive experimentation of the American Gas Association. They are shown to represent the results of observation somewhat better than any method previously proposed.