LPG Properties & LPG Composition – What Are the Properties of LPG
Water boils at 100°C or 212°F, becoming a gas (steam). In contrast, LPG (propane) boils at -42°C or -44°F, becoming gas vapour. LPG stays liquid because it is under pressure in a gas cylinder. Liquid density is about half that of water.
In its natural state, LPG is a colourless and odourless gas. Odourant is added for safety.
LPG Composition – Components of LPG
LPG composition includes propane, butane & isobutane.
LPG composition is primarily propane, butane, isobutane, butylenes, propylene and mixtures of these gases, which are the components of LPG and all with different LPG properties. LPG is composed of liquid or gas (vapour), depending on pressure and LPG gas temperature.
The domestic LPG composition and the commercial LPG composition are typically the same propane, butane or a mixture of the two gases.
LPG – Liquefied Petroleum Gas – is produced during natural gas processing and petroleum refining.
Natural Gas Liquids – NGL – have the same LPG composition and gas temperatures plus a few more gases not normally included in LPG.
The full NGL list of components of LPG includes ethane, ethene, butylenes, propylene, propene, isobutene, butadiene, pentane, pentene and pentanes plus, as well as propane, butane and isobutane.
LPG Gas Constituents
Liquefied Petroleum Gas – LPG – constituents are primarily propane, butane, isobutane, butylene, propylene and mixtures of these gases. LPG gas constituents are produced from crude oil reefing and natural gas processing. They are liquid under pressure and gas at room temperature and pressure.
LPG Properties – What are the Properties of LPG – Properties of Propane and Butane
The properties of LPG (properties of propane and butane) include: LPG is liquid under pressure but becomes gaseous in ambient conditions. LPG vapour is about 1.55 (propane) to 2.08 (butane) times heavier than air. LPG boiling point is between -42°C to -0.4°C, depending on the propane to butane constituent ratio in the LPG gas mixture.
The properties of LPG (propane) are -42°C boiling point, -188°C freezing point, heavier than air density, C3H8 chemical formula, 1967ºC flame temperature, 470°C auto ignition temperature, -104°C flash point, temperature based pressure, Ethyl Mercaptan odour, 2.15% to 9.6% LPG/air limits of flammability and more.
List of LPG Properties – Properties of Propane and Butane
Properties of LPG (properties of propane and butane) include:
LPG is primarily propane and butane. Both gases have adiabatic flame temperature of about 1970°C, when burned in air.
LPG (propane) gas boiling point temperature: -42 °C or -44 °F
LPG (propane) gas melting/freezing temperature: -188 °C or -306.4 °F
Propane boiling point – LPG (Propane) Vaporisation
Heavier than Air LPG density (Propane Density) – LPG specific gravity (Propane specific gravity)
LPG composition – components – constituents: Propane, Butane & Isobutane
LPG chemical formula – molecular formula: C3H8 or C4H10
LPG gas flame temperature: 1967 ºC or 3573 ºF
LPG-Propane ignition temperature (in air): 470°C – 550°C (878°F – 1020°F)
LPG-Propane auto ignition temperature: 470 °C or 878 °F
LPG flash point: -104°C or -156°F
LPG vapour pressure: 637 kPa @ 27°C (128 PSIG @ 80°F)
LPG odour: Ethyl Mercaptan added
LPG appearance: clear
LPG energy content: 25 MJ/L or 91,547 BTU/Gal (60°F)
Gaseous expansion of LPG: 1 L (liquid) = 0.27 M3 (gas)
Combustion formula for LPG: C3H8 + 5 O2 → 3 CO2 + 4 H2O + Heat (complete combustion)
LPG limits of flammability: 2.15% to 9.6% LPG/air
LPG properties nomenclature
Molecular weight of LPG components: Propane is 44.097 kg/kmole – Butane (n-butane) is 58.12 kg/kmole
All of the above are the properties of LPG.
We’ll review these most commonly referenced LPG properties…
Propane Ignition Temperature in Air – Ignition Temperature of Propane Gas
The propane ignition temperature in air (ignition temperature of propane gas) is when it reaches a temperature between 470°C – 550°C (878°F – 1020°F). At this temperature, the propane will ignite without the need for a flame, spark or other ignition source. Propane flame temperature is 1967°C (3573ºF).
LPG Properties Chart
LPG (Propane) Chemical Properties Chart
LPG – Propane Boiling Point
-42 °C or -44 °F
LPG Melting – Freezing Point
-188 °C or -306.4 °F
Specific Gravity of Liquid LPG-Propane
LPG Density Propane Gaseous Density
1.898 kg/m3 (15°C) or 0.1162 lb/ft3
Energy Content of LPG
25 MJ/L or 91,547 BTU/Gal (60°F)
LPG Gaseous Expansion
1 L (liquid) = 0.27 M3 (gas)
Propane Flame Temperature
1967 ºC or 3573 ºF
Propane Ignition Temperature in Air 470°C – 550°C (878°F – 1020°F)
Limits of Flammability
2.15% to 9.6% LPG/air
Propane Auto Ignition Temperature
470 °C or 878 °F