Difference Between Natural Gas and Propane

Main Difference – Natural Gas vs Propane

Natural gas and propane are combustible gases. Natural gas is a mixture of several different compounds. It is a fossil fuel. Propane is composed of propane molecules. It is a hydrocarbon. Propane is compressible and can be liquefied into a transportable liquid. Since natural gas and propane are fuels, they are very important for the energy production. When considering their effect on environment, propane is more environmental friendly than natural gas. The main difference between natural gas and propane is that propane is heavier than air in gaseous phase whereas natural gas is lighter than air.

Key Areas Covered

1. What is Natural Gas
      – Definition, Composition, Properties, Uses
2. What is Propane
      – Definition, Properties, Uses
3. What is the Relationship Between Natural Gas and Propane
      – Natural Gas and Propane
4. What is the Difference Between Natural Gas and Propane
      – Comparison of Key Differences

Key Terms: Butane, Carbon Dioxide, Crude Oil, Ethane, Fossil Fuel, LPG, Methane, Natural Gas, Petroleum, Propane, Relative Density

What is Natural Gas

Natural gas is a mixture of simple hydrocarbon compounds. This gas is combustible and is usually found from deep underground locations where the decay of organic matter has taken place for millions of years. Natural gas is mainly composed of methane. The other components present in natural gas include simple alkanes, carbon dioxide, nitrogen, and helium. Therefore, the combustion of natural gas produces byproducts such as carbon dioxide, water vapor, and nitrogen oxides.

Figure 1: Formation of Natural Gas

Natural gas is lighter than air. This is because the relative density of natural gas is lower than 1. Due to this reason, natural gas will come to the top of a container in a mixture of natural gas and normal air. Natural gas cannot be stored in special tanks. A connection to a natural gas network has to be made in order to obtain the gas.

Natural gas is often referred to as the cleanest fuel since it produces a very less amount of carbon dioxide and other harmful substances when compared to crude oil. But natural gas can cause the production of pollutants such as carbon monoxide, sulfur dioxide, and nitrogen oxides.

According to research, it has been found that most of the natural gas reserves are found in the Mid-East countries.

Figure 2: Natural Gas Resources in the World

Natural gas processing is a process where the raw natural gas is converted into gas that can be sold. This process produces a lot of byproducts such as alkanes, natural gasoline, etc. Alkanes include simple hydrocarbons like ethane, propane, and butane. In other words, natural gas processing refers to the removal of butane, propane, and ethane. This removal is done in order to avoid condensation of this gas inside pipelines.

The components and their percentages of natural gas may vary from one location to another.

Major Components of Natural Gas

• Methane
• Ethane
• Propane
• Iso-butane
• Butane
• Iso-pentane
• Pentane
• Hexane
• Carbon dioxide

What is Propane

Propane is a combustible gas having the chemical formula C₃H₈. The molar mass is about 44 g/mol. It is a colorless and odorless gas. Propane is compressible and can be made into transportable liquid fuel. Propane is a simple alkane that has no unsaturation. Propane can be produced as a byproduct of either natural gas processing or petroleum refining. Therefore, the major sources of propane are natural gas and petroleum oil.

Combustion of propane produces carbon dioxide, water vapor, and heat energy when it undergoes complete combustion. But in the presence of a low amount of oxygen, propane undergoes incomplete combustion, producing carbon dioxide, carbon monoxide, water vapor and heat energy.

The boiling point of propane is about -42^oC. This low boiling point causes it to vaporize quickly. Therefore, even it is compressed and made as a liquid, this quick vaporization helps to use this gas as an energy source (Ex: LPG). This indicates that propane liquid does not need any vaporizing agent to make it vaporize.

Figure 3: Propane can be liquefied at relatively low pressures and is filled into gas cylinders for storage and for the easiness of usage.

Propane is heavier than normal air because the relative density of propane is higher than 1. Therefore, it is collected at the bottom of a container where it is present along with normal air.

Relationship Between Natural Gas and Propane

• Propane can be obtained from natural gas processing since natural gas is composed of a considerable amount of propane as a constituent.

Difference Between Natural Gas and Propane

Definition

Natural Gas: Natural gas is a mixture of simple hydrocarbon compounds.

Propane: Propane is a combustible gas having the chemical formula C₃H₈.

Density

Natural Gas: The relative density of natural gas is low. Therefore, it is lighter than air.

Propane: The relative density of propane gas is high. Therefore, it is heavier than air.

Storage

Natural Gas: Natural gas cannot be stored in tanks.

Propane: Propane can be stored in tanks.

Components

Natural Gas: Natural gas is composed mainly of methane and other simple hydrocarbon substances.

Propane: Propane is composed of propane molecules.

Compressibility

Natural Gas: Natural gas cannot be easily compressed in order to liquefy the gas.

Propane: Propane can be easily compressed to make propane liquid.

Effect on Environment

Natural Gas: Natural gas produces a less amount of harmful substances than crude oil.

Propane: Propane produces a high amount of harmful substances compared to natural gases.

Conclusion

Natural gas and propane are important energy sources. Since natural gas cannot be stored in tanks, it is only available where natural gas networks are located. Therefore, propane is a good alternative for areas where natural gas is unavailable. Propane is present in natural gas in a considerable amount. Therefore, natural gas is a good source for the production of propane. The main difference between natural gas and propane is that gaseous propane is heavier than air phase whereas natural gas is lighter than air. This is because the relative density of propane is higher than 1 whereas the relative density of natural gas is lower than 1.

References:

1. “Chemical Composition of Natural Gas – Union Gas.” Uniongas.com. N.p., n.d. Web. Available here. 03 Aug. 2017. 
2. “Propane.” Wikipedia. Wikimedia Foundation, 31 July 2017. Web. Available here. 03 Aug. 2017. 

Image Courtesy:

1. “Natural gas formation” by Siyavula Education (CC BY 2.0) via Flickr
2. “World Natural Gas proven reserves 2005” By Tosaka – Own work by uploader (ref:藤田和男ほか監修 佐々木詔雄ほか編著 『天然ガスの本』 日刊工業新聞 2008年3月25日初版1刷発行 ISBN 9784526060243) (CC BY 3.0) via Commons Wikimedia
3. “Propane tank 20lb” By Hustvedt – Own work (CC BY-SA 3.0) via Commons Wikimedia