The main differences between LPG, LNG, and CNG lie in their composition, production process, and physical form: LPG is liquefied petroleum gas (a mixture of propane and butane), 

LNG is methane liquefied at -162°C, and CNG is high-pressure compressed gaseous methane.

Key Difference Comparison

Compositional Characteristics.

LPG (liquefied petroleum gas): A mixture of propane and butane, containing small amounts of propylene, butene, and sulfides. It has a high molecular weight and a higher density than air.

LNG (liquefied natural gas) and CNG (compressed natural gas): Both are primarily methane (>90%), have a simple molecular structure, and are less dense than air.

LPG: L (Liquefied), meaning liquefied. LPG, commonly known as liquefied petroleum gas, is a colorless, volatile gas obtained by pressurizing, cooling, and liquefying petroleum or natural gas in a refinery.

LNG: N (Natural), meaning natural gas. LNG, commonly known as liquefied natural gas, is a cryogenic liquid fuel that can be stored and transported at normal pressure.

CNG: C (Compressed), meaning compressed. CNG, commonly known as compressed natural gas, is a gaseous form of natural gas that is pressurized and stored in containers.

Different sources

LPG: Gas produced during crude oil refining or volatilized during oil or natural gas extraction. LPG is a mixture of oil and natural gas under appropriate pressure.

LNG: Liquefied natural gas is produced by purifying natural gas produced in a gas field and then liquefying it at ultra-low temperatures (-162°C) at atmospheric pressure. 

It is transported by specialized ships or tankers and then re-gasified for use.

CNG: Natural gas produced in a gas field is compressed to a pressure greater than or equal to 10 MPa and less than 25 MPa after processing. It is pressurized and stored in a container.