What is Propylene?
You have probably heard the term ‘propylene’ or ‘propene’, but it is likely that you have no real understanding of what it is, not unless you have direct contact or use with this organic compound. Propylene (C3G6) is one of the most important of the many organic compounds that are industrially produced. This compound is an alternative fuel gas that comes with multi-purpose uses known to offer outstanding performance and it is quite advantageous in terms of both safety and economy.
Characteristics of Propylene
The alternative fuel is characterized by being colorless and liquefied flammable gas which is quite sweet and pungent in odor. Compared to acetylene, its BTU (British thermal unit) capacity is moderate in the primary while high in the secondary flame. Also, the heat that is released in its primary flame is a bit less compared to that off acetylene. On the other hand, its BTU capacity is superior to that of acetylene in the outer flame. Propylene is most known for being superior in its combustion performance. Although it is colorless and thus invisible it does have a recognizable odor. While it is similar to propane, propylene has a double bond which is what gives it combustion advantage, making it extremely flammable but at the same time non-toxic. Basically, this alternative fuel combines acetylene flame’s qualities together with the heating capacity of propane.
How is Propylene Gas Manufactured?
There are two ways in which propylene gas is manufactured (synthesized being the correct term) – first being the side effect of refining petroleum and secondly as result of a procedure called cracking. Cracking, also splitting or reforming, of the hydrocarbon molecules is one of the ways of obtaining this fuel. This is done by heating natural gas or a straight-chain gasoline (straight line petrol) at a very high temperature together with steam. Using this procedure, propylene is synthesized along with ethylene and many additional organic compounds. Sometimes, propylene can be produced naturally as well when organic matter is burned.
Propylene Products and Safety of Use
Propylene products synthesized from propylene gas include a wide selection of organic compounds. A lot of these products are components of plastics while some are industrial compounds which are actually polymers of hydrocarbons. In terms of safety, propylene is known to be very stable. It does not react to copper and are quite insensitive when it comes to shock. Furthermore, propylene tends to decompose when oxygen is absent and has a distinct quality of having narrow explosive limitations when it comes to air, which adds to its safety profile compared to acetylene.
Short term exposure to propylene gas is not harmful. However, when you are exposed to high concentrations of the alternative fuel, it may have some anesthetic effect. On the other hand, contact with liquid propylene is not safe since it can cause frost bite burns. Propylene is a much better alternative to that of propane when it comes to cutting and heating as it is far superior in performance. That being the case, it is widely used as fuel gas on HVOF processes and the plastics industry rely heavily on propylene being a fuel gas. Applications of propylene that is non-fuel includes producing materials like acetone.
Cutting & Heating
A very significant use in light industry is when Propylene is used with Oxygen for heating, cutting and welding. Due to its higher total heat content it is superior to both Propane and Acetylene for heating and cutting. Propylene’s secondary flame has more heat than Acetylene’s and is longer thus giving it superior cutting performance especially so in thicker metals. For welding the primary flame is used, which is hotter and more concentrated in Acetylene than in Propylene giving Acetylene the advantage. Notwithstanding its higher cost and lower safety profile Acetylene is the best choice for welding and brazing. For heating and cutting Propylene is hands down the best choice and for a combination of all operations Propylene is probably the best choice.
If you are cutting or welding inside a vessel such as a tank or a ship them Acetylene might be safer. Acetylene is lighter than air whilst Propylene is not. If there are any hose leaks Acetylene will rise out of the vessel. Propylene will sink and build up.
