Fuels

Propane. The most popular grills in America are fueled by propane. Propane and natural gas are similar but different fuels. The hoses on a gas grill will tell you which fuel the grill uses, because propane hoses are about half the diameter of natural gas hoses. Why? Because propane gas has the ability to be compressed into a liquid, reducing its volume and making it suitable for storage in a portable tank. Propane, properly termed LP gas or liquid petroleum gas, comes from the refining of crude oil and natural gas. Liquid petroleum gas is composed of 90 to 95 percent propane and smaller amounts of propylene, butane, and butylene. It’s colorless and odorless, but ethyl mercaptan is added so you can smell it easily for safety purposes. Inside the container, LP gas is in two states of matter: liquid and vapor. The liquid falls to the bottom and the vapor remains on top. Most propane tanks are filled to about 80 percent capacity, leaving about 20 percent for the vapor to expand during ambient temperature fluctuations. Propane tanks also come with an overfill protection device, or OPD, to prevent hazardous overfilling of the tank. When you open the gas valve and withdraw pressurized liquid propane from the tank, it reverts from its liquid state back to a gaseous state. Propane (C3H8) has three carbon atoms and eight hydrogen atoms. Unlike solid fuels such as lump charcoal, gaseous fuels like propane emit water vapor when burned, due to their hydrogen atoms, meaning that they don’t burn as hot or as dry as coals.