LPG Gas Properties | Chemical and Physical Properties of LPG
LPG gas properties include the chemical properties of LPG and the physical properties of LPG. Included in the LPG properties are boiling point, density, energy content, flame temperature, chemical formula, expansion and more.
LPG Composition
LPG composition is primarily propane, butane, isobutane, and mixtures of these gases.
LPG – Liquefied Petroleum Gas – is produced during natural gas processing and petroleum refining.
LPG – Liquefied Petroleum Gas – describes flammable hydrocarbon gases.
LPG, liquefied through pressurisation, comes from natural gas processing and oil refining.
In different countries, the supply can be propane, butane or propane-butane blends.
In Australia, LPG is just propane.
LPG exists as liquid or gas (vapour), depending on pressure and temperature.
Natural Gas Liquids – NGL – have the same LPG composition plus a few more gases not normally included in LPG.
The full NGL list includes ethane, ethene, butylenes, propylene, propene, isobutene, butadiene, pentane, pentene and pentanes plus, as well as propane, butane and isobutane.
LPG – Propane Properties
LPG (propane) has many properties including:
- propane boiling point
- propane density – LPG (propane) specific gravity
- LPG composition – components – constituents
- chemical formula – molecular formula
- flame temperature
- autoignition temperature
- flash point
- vapour pressure
- odour
- appearance
- energy content
- gaseous expansion
- combustion formula
- limits of flammability
- nomenclature
- molecular weight
We’ll review these most commonly referenced properties…
LPG (Propane) Properties Chart
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LPG – Propane Boiling Point
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-42 °C or -44 °F
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LPG Melting – Freezing Point
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-188 °C or -306.4 °F
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Specific Gravity of Liquid LPG
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0.495 (25°C)
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LPG – Propane Gaseous Density
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1.898 kg/m3 (15°C) or 0.1162 lb/ft3
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Energy Content of LPG
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25 MJ/L or 91,547 BTU/Gal (60°F)
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LPG Gaseous Expansion
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1 L (liquid) = 0.27 M3 (gas)
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Propane Flame Temperature
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1967 ºC or 3573 ºF
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Limits of Flammability
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2.15% to 9.6% LPG/air
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Autoignition Temperature
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470 °C or 878 °F
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Molecular Weight
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44.097 kg/kmole
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LPG – Propane Boiling Point
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.
As a liquid, it looks a lot like water.
It is colourless and odourless in its natural state.
LPG – Propane Density and Specific Gravity
LPG – propane – gas density is 1.55 times heavier than air at 1.898 kg/m3 vs 1.225 kg/m3 for air (both 15°C at sea level).
LPG – propane – liquid density is about half that of water at 495 kg/m3 (25°C) vs 1,000 kg/m3 (4°C) for water.
Specific gravity of propane and water is 0.495 (25°C) and 1.000 (4°C), respectively.
LPG Density – Specific Gravity of Liquid LPG – Propane
Unlike water, 1 kilogram of LPG does NOT equal 1 litre of LPG.What is the Density of LPG Gas? LPG – Propane is Heavier than Air
10 Important LPG – Propane Facts
1. LPG (or LP Gas) is the acronym for Liquefied Petroleum Gas or Liquid Petroleum Gas.
2. LPG is a group of flammable hydrocarbon gases liquefied through pressurisation.
They are, in most cases, used as fuel.
3. LPG comes from natural gas processing and petroleum refining.
4. There are a number of gases that fall under the “LPG” label.
These include propane, butane and isobutane (i-butane), as well as mixtures of these gases.
5. LPG gases are compressible into liquid at low pressures.
6. The common uses for LPG include use for fuel in heating, cooking, hot water and vehicles.
It is also utilised for refrigerants, aerosol propellants and petrochemical feedstock.
7. LPG is stored, as a liquid, in steel vessels ranging from small BBQ gas bottles to larger gas cylinders and storage tanks. (45kg gas bottles shown)
LPG = Propane
In Australia, LPG is propane.
LPG Gas Temperature: Flame, Boiling Point, Melting/Freezing Point
LPG gas temperature includes LPG gas flame temperature, LPG gas boiling temperature and LPG gas freezing temperature. LPG – liquefied petroleum gas – temperature also affects the gas cylinder pressure.
LPG gas flame temperature (when burned with air) is 1967ºC or 3573ºF.
LPG (propane) gas boiling temperature is -42°C or -44°F, as compare to water at 100°C or 212°F
The LPG boiling point is where liquid propane boils and becomes vapour (gas).
LPG (propane) gas melting/freezing temperature is at -188°C or -306.4°F.
So, LPG gas temperature for freezing is a much lower temperature than water, which freezes at 0ºC.
LPG – Propane Pressure Varies with Temperature
As mentioned before, LPG is stored in a gas bottle under pressure.
The term “pressure” refers to the average force per unit of area that the gas exerts on the inside walls of the gas bottle.
(LPG Pressure-Temperature Chart shown)
Pressure measurement is in kilopascals (kPa) or pounds per square inch (psi).
“Bar” is yet another unit of measure for pressure.
1 Bar = 100 kPa, so it is metric based but not an SI unit of measure.
LPG pressure can vary based on temperature, as shown in the chart.
The level of fill in the gas bottle comes into play when the LPG is in use, as it affects the rate of vapourisation.
LPG is a liquefied gas. So, the pressure inside the cylinder will remain the same from full until the vaporistion of the last of the liquid LPG.
Then the pressure will fall, with the use of the last of the LPG vapour.
Odourant Added for Safety
Avoid Direct Contact – Cold Burns
Energy Content of LPG – Propane
Calorific Value of Water Gas
LPG Gaseous Expansion
LPG expands to 270 times the volume when it goes from liquid to gas.Combustion Formula Equation for LPG – Propane
What’s the Equation for Incomplete Combustion of Propane?
2 C3H8 + 9 O2 → 4 CO2 + 2 CO + 8 H2O + heat
LPG Gas Temperature: LPG – Propane Flame Temperature
Limits of Flammability
LPG Flash Point Temperature
Autoignition Temperature – Propane & Butane
Dissipation
Molecular Weight for LPG – Propane – Butane – Isobutane
LPG Vapour (Gas) Use vs. Liquid Use
6 Things You Didn’t Know About LPG
While you may know some of these facts, chances are you don’t know all of them.
Have a read and learn more about:
1. Real LPG Explosions are Really Rare
2. Simulated Natural Gas from LPG
3. The Source of LPG
4. Australian Made Energy
5. LPG is a Renewable Energy Source
6. LPG is NOT Coal Seam Gas (CSG)
1. LPG Cylinder Explosions are Extremely Rare + Video
Hollywood and the media would have you believe that LPG cylinder explosions are a common event.
In fact, explosions are quite rare and it is quite difficult to even make an LPG cylinder explode on purpose.
You’ll enjoy watching the Myth Busters Video where they try to make a cylinder explode.
Most gas explosions are the result of gas leaking into a confined space, like a kitchen.
This is no more likely with LPG than with piped natural gas.
Often, the gas bottle itself is not even involved in the event, as gas bottles are always stored outdoors.
2. Simulated Natural Gas from LPG
Most people have never even heard of Simulated Natural Gas (SNG) let alone know that it can be made with LPG.
Mixing vapourised LPG with air produces SNG.
We can SNG use in place of natural gas, as it has near identical combustion characteristics.
It can be used alone or mixed with regular natural gas.
There are no changes required in burners, regulators or gas jets.
There are a number of reasons to use SNG:
• To help meet peak demand when natural gas supplies are inadequate
• To operate while in preparation for the start-up of a natural gas supply
• As a stand-by in the event of a natural gas supply disruption
Simulated natural gas has a few names.
Besides SNG, it is also called propane-air and LPG-air.
3. The Source of LPG
Many people mistakenly think of LPG as a by-product.
In reality, LPG is a valuable co-product produced from gas fields and crude oil refining.
They process the gas stream from natural gas fields to separate the gases present.
These include methane, ethane, propane, butanes and pentanes.
Impurities are also removed, including water.
The produced gases are each funnelled into their own supply streams.
They capture propane and butane, the two common types of LPG, and store them in their liquefied form.
The same is true of crude oil refining.
The refinery process creates many co-products.
The co-products include gasoline, diesel fuel, asphalt base, heating oil, naphtha, kerosene and LPG.
4. LPG is Australian Made Energy
LPG is the only motor fuel in which Australia is self-reliant.
Unlike both petrol and diesel, for which Australia relies on imports, we produce more LPG than we consume.
Not only is Australia completely self-sufficient in LPG but it is also a net exporter of LPG.
In 2013, Australia produced 2.3 Million tonnes of LPG.
That satisfied the local demand of 1.5 million tonnes, with net exports of 815,000 tonnes.
5. LPG is now a Renewable Energy Source
LPG has gone from being a traditional fossil fuel to a new form of renewable energy.
Scientists have created a genetically engineered version of the common E. coli bacteria.
This version produces propane (LPG).
So, LPG is now a renewable energy.
The bacteria consume sugar.
With genetic modification, and the help of a couple of enzymes, they make propane.
The propane produced is chemically identical to regular propane.
6. LPG is NOT Coal Seam Gas (CSG)
There is some confusion over what Coal Seam Gas (CSG) is and what it is not.
While CSG may contain various gases, typical CSG is 95% to 97% pure Methane.
LPG is not Methane.
LPG is Propane.