When room temperature propane is released, it vaporizes and dissipates into the atmosphere.
It’s important to know when propane is released because it can be dangerous if it reaches an ignition source. Propane is flammable, and it can ignite when combined with air at temperatures between 2.2 to 9.6 percent of the propane vapor in the mixture.
When it’s released, propane vaporizes into liquid and gaseous forms as it displaces the air. It may collect in low areas inside a structure or outside the structure, where it can be ignited. It can also cause damage or injury if it leaks into the air.
The flammability range for propane is very narrow, compared with gasoline and other petroleum products. It will not ignite unless the air mixture contains from 2.2 to 9.6 percent propane vapor and is able to reach a minimum temperature of 940 degrees Fahrenheit.
Unlike other hydrocarbons, propane has C-C bonds that are nonpolar, or cannot separate into two different bonds. This means that the bonding forces are weak and do not lead to the formation of permanent dipole moments, which is how hydrogen bonds are formed in liquids such as water or ethyl alcohol.
Because of its nonpolar nature, propane undergoes combustion reactions that are much cleaner than those of other alkanes such as gasoline and coal. It produces a lower per-BTU amount of carbon dioxide and water vapor, which reduces harmful exhaust fumes.
Propane is a fossil fuel, and it was formed millions of years ago from the remains of sea animals and plants that died and were trapped in rocks deep beneath the earth. The pressure and heat from the earth over time changed these remnants into natural gas and petroleum deposits.
Liquid propane is stored in tanks with the right amount of pressure to keep it liquid. If it were not kept under this pressure, it would quickly liquefy and turn into gas, which can be very dangerous.
A tank with a hundred thousand gallons of propane at a pressure of about 850 kPa (123 PSI) can hold enough fuel to run a family’s cooking equipment for weeks. A tank with a thousand gallons of propane at the same pressure can store enough fuel to run an entire furnace or heat pump for a year, according to the U.S. Department of Energy’s National Energy Technology Laboratory.
During normal combustion, the propane molecule is oxidized to produce hydrogen gas and carbon monoxide. It also yields a small amount of methanol and aldehydes such as formaldehyde, acetaldehyde, and methyl ethyl ketone.
If the propane molecule is left at a high temperature, it will break into smaller molecules, which can be further broken down to ethylene and propylene. In addition, a small amount of ethane and butane can be formed as well.
When it is liquified, the propane molecule can be stored in metal tanks with the right amount of pressure to keep its shape and prevent the formation of harmful vapors. It is then ready to be used as a fuel. It takes up less space, and it can be transported more easily as a liquid than as a gas.