The Flammability of Fuel Mixtures in Air Containing Propane and Butane

The behavior of the lean and rich flammability limits of various fuel mixture combinations involving propane, n-butane, propylene and ethylene, which feature prominently in a variety of industrial and natural fuel gases such as liquefied petroleum gases (LPGs), was examined. It was found that the lean limits of such mixtures can be predicted well by using Le Chatelier’s Rule. This rule can also predict the rich flammability limits of propane-n-butane mixtures. However, its application to calculate the rich limits of mixtures such as propane-propylene, propane-ethylene, butane-ethylene, propylene-ethylene mixtures carries a significant error with certain mixtures composition. The effect of the dilution of such fuel mixtures with nitrogen or carbon dioxide was also investigated and a predictive procedure is described.