Glossary Terms

An oil refining unit in which naphthas are changed chemically to increase their octane level. Paraffins convert to iso-paraffins and naphthenes, and naphthenes change to aromatics. The catalyst used is usually platinum, though sometimes palladium.

Refinery yield (expressed as a percentage) represents the percent of finished product produced from input of crude oil and net input of unfinished oils. It is calculated by dividing the sum of crude oil and net unfinished input into the individual net production of finished products. Before calculating the yield for finished motor gasoline, the input of natural gas liquids, other hydrocarbons and oxygenates, and net input of motor gasoline blending components must be subtracted from the net production of finished motor gasoline. Before calculating the yield for finished aviation gasoline, input of aviation gasoline blending components must be subtracted from the net production of finished aviation gasoline.

Petroleum products produced at a refinery or blending plant. Published production of these products equals refinery production minus refinery input. Negative production will occur when the amount of a product produced during the month is less than the amount of that same product that is reprocessed (input) or reclassified to become another product during the same month. Refinery production of unfinished oils, and motor and aviation gasoline blending components appear on a net basis under refinery input.

The raw materials and intermediate materials processed at refineries to produce finished petroleum products. They include crude oil, products of natural gas processing plants, unfinished oils, other hydrocarbons and oxygenates, motor gasoline and aviation gasoline blending components and finished petroleum products.

Total crude oil (domestic plus foreign) input to crude oil distillation units and other refinery processing units (cokers, etc.).

A refinery-produced stream that is composed predominantly of normal butane and/or isobutane and may also contain propane and/or natural gasoline. These streams may also contain significant levels of olefins and/or fluorides contamination.

An installation that manufactures finished petroleum products from crude oil, unfinished oils, natural gas liquids, other hydrocarbons and oxygenates.

A carrier subject to economic regulation by the Department of Transportation.

The residual product left after a reforming process. The term also has been more generally used in reference to any low octane product left over after any secondary refining process. Preferable to natural gasoline in ethanol/gasoline blends because of the low RVP (4 to 8).

Petroleum products sold at the wholesale level from primary storage. Refers to loading racks where tanker trucks fill up. See also Over the Rack.