The technology of directly oxidising propylene to make Propylene oxide is still being developed. Formerly, propylene oxide was made via the chlorohydrin process, which generates a significant amount of calcium chloride as a byproduct. Propylene oxide is now produced in the mainstream process from peroxides such as ethyl benzene and propylene. As a byproduct, this procedure generates propylene oxide (PO) and styrene (SM). With this method, we build large-scale SM/PO plants.
Propylene is a three-carbon olefin that is similar to propane but has one double bond. In a refinery, propane is used as a feedstock for the alky unit, which produces C3 alkylate for blending into gasoline. Propylene is also frequently isolated and marketed as a feedstock to the petrochemical industry for the production of polypropylene polymers. The FCC unit is the primary source of refinery propylene. Other cracking units, such as the coker, create small amounts of propylene, but they are less likely to be separated for use in the alky. Propylene can also be manufactured on purpose by dehydrogenating propane, but this is rarely done in a refinery. In the absence of an alky unit, propylene is often used in LPG blending or refinery fuel, both of which are very low-value possibilities.
