Olefins

Olefins are unsaturated hydrocarbons containing a double bond between two carbon atoms. Examples are butylene and propylene.

Olefins in finished petroleum products

In gasoline, olefins contribute to octane, which is beneficial. However, because they tend to form harmful deposits inside of engines, there are typically limits set on total olefin content.

Refinery streams containing high percentages of olefins, such as coker naphtha, have a tendency to polymerize and form gums that can cause problems in storage and transportation systems, so these streams usually are hydrotreated to saturate the olefins

Some refineries produce olefins such as propylene as a product, typically as a feedstock to petrochemicals.

Olefins in refinery feedstocks

In a refinery, olefins are an important feedstock into the alkylation unit to produce alkylate (a high-value gasoline blend stock). The olefins most commonly used in the alkylation unit are butylene and propylene, which primarily come from the FCC unit.

The Refinery Reference Desk includes content derived from our industry experts as well as from public data sources such as company websites. Nothing herein is intended to serve as investment advice. This material is based on information that we believe to be reliable and adequately comprehensive, but we do not represent that such information is in all respects accurate or complete. McKinsey Energy Insights does not accept any liability for any losses resulting from use of the content.



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