Discover how propylene combines high combustion heat with high vapor pressure for high-velocity spraying and more.
Propylene Fuel Gas
Superior Combustion Performance with a Double Bond
Discover why high combustion heat and flame temperature coupled with high vapor pressure make propylene the ideal fuel gas for high-velocity spraying processes.
Properties of Propylene Fuel Gas
Propylene (C3H6) is a colorless, non-toxic fuel gas with a naturally pungent smell. Although similar to propane, it has a double bond between the second and third carbon atoms, which gives it a combustion advantage. In other words, it produces a flame with higher temperature with either oxygen or air. Compared with acetylene, it has moderate BTU (British thermal unit) capacity in its primary flame and high BTU capacity in its secondary flame. The heat released in the primary flame cone is slightly less than that of acetylene. The BTU capacity of the outer flame is superior to that of acetylene. Propylene combines the qualities of an acetylene flame with the secondary heating capacity of propane. This fuel gas burns hotter than propane.
Propylene is extremely flammable with explosive limits in air of between 2% and 11% by volume. It is heavier than air, so if it escapes, it will flow to the lowest level and collect in trenches, ducts and drains, forming an explosion hazard.
At an ambient temperature of 20°C (68°F), propylene liquefies at 10.2 bar. This property enables this fuel gas to be easily stored as a liquid and used as a gas. When the pressure is reduced by opening the outlet valve, the liquid boils and releases gas at a pressure level slightly less than that of the cylinder.
How is Propylene Fuel Gas Generated?
Propylene is obtained during the refining of gasoline. But it can also be produced by splitting, cracking and reforming hydrocarbon mixtures. It is separated from hydrocarbon fractions by means of fractional distillation. For higher product qualities, further distillation is required. The shale gas industry has opened up an alternative production path, namely the dehydrogenation of propane to yield propylene.
The gas can then be supplied as a liquid in cylinders at the vapor pressure of propylene, and in economical bulk fuel gas tanks of varying capacities.
Benefits of Propylene Fuel Gas at a Glance
- Superior combustion performance thanks to double bond
- Good heat transfer, providing effective heat input to the workpiece
- High vapor pressure, making it ideal for high-velocity processes
- Ease of liquefaction and storage
What is Propylene Fuel Gas Used for?
Propylene can be used for any metal fabrication application that is also suited to propane. The productivity gains enabled by its superior combustion performance make it an attractive alternative for many heating and cutting tasks. The higher heat distribution in the inner cone means that the propylene flame is better at producing localized heat. This gives propylene an advantage over propane when a sharper focused flame is required. Typical metalworking tasks include the cutting of thick steels.
It also has a higher vapor pressure, which makes it ideal for thermal spraying processes such as high-velocity oxygen fuel (HVOF) processes and flame spraying. Its high thermal energy provides the temperatures needed to melt process powders or wire feedstock so they can be sprayed onto the target surface.
At a pressure of around 8 to 9 bar, propylene is ignited in oxygen in the HVOF gun, producing a high-velocity flame that leaves the gun at supersonic speeds. The energy to create the bond is largely provided by the velocity of the particles rather than heat transfer. This property gives HVOF an advantage over many other spraying processes as it produces exceptionally hard, dense, wear-resistant coatings that adhere strongly to the substrate. These properties are particularly valuable in quality-critical industries such as aerospace, automotive, oil and gas, and manufacturing.
In addition, the chemical and plastics industries rely on propylene as a fuel gas.
Non-fuel applications include organic synthesis to produce materials such as acetone. Propylene can be polymerized to form polypropylene plastic. It can also be employed as a refrigerant, or in calibration mixtures and as a chemical intermediate. In addition, it is used for efficiency testing of gas burners and engines.
Propylene Supply Options
We supply propylene in cylinders of different sizes in purity grades ranging from 95% for general industrial applications through 99.5%+ for high-purity applications (2.5) all the way to 99.8%+ for instrumentation and research purposes. In some regions, we also offer drums or bulk tanks with different capacities.
We also supply propylene in liquid withdrawal cylinders for applications that require high flow rates and high pressures. These use an external low-pressure nitrogen supply to expel the liquid, which is vaporized in a heat exchanger. With this supply option, heat-traced pipelines may be required to prevent condensation caused by the cooling of the gas under pressure.