Definitions, Sources and Explanatory Notes

 Category:   Petroleum Refining & Processing
 Topic:   Production Capacity of Operable Petroleum Refineries


Key Terms Definition
Alkylate The product of an alkylation reaction. It usually refers to the high octane product from alkylation units. This alkylate is used in blending high octane gasoline.
Aromatics Hydrocarbons characterized by unsaturated ring structures of carbon atoms. Commercial petroleum aromatics are benzene, toluene, and xylene (BTX).
Asphalt A dark-brown-to-black cement-like material containing bitumens as the predominant constituent obtained by petroleum processing; used primarily for road construction. It includes crude asphalt as well as the following finished products: cements, fluxes, the asphalt content of emulsions (exclusive of water), and petroleum distillates blended with asphalt to make cutback asphalts. Note: The conversion factor for asphalt is 5.5 barrels per short ton.
Barrel A unit of volume equal to 42 U.S. gallons.
Barrels Per Stream Day The maximum number of barrels of input that a distillation facility can process within a 24-hour period when running at full capacity under optimal crude and product slate conditions with no allowance for downtime.
Hydrogen The lightest of all gases, occurring chiefly in combination with oxygen in water; exists also in acids, bases, alcohols, petroleum, and other hydrocarbons.
Isobutane A normally gaseous branch-chain hydrocarbon. It is a colorless paraffinic gas that boils at a temperature of 10.9º F. It is extracted from natural gas or refinery gas streams.
Isohexane A saturated branch-chain hydrocarbon. It is a colorless liquid that boils at a temperature of 156.2 degrees Fahrenheit.
Isooctane Isooctane (C8H18). A saturated branch-chain hydrocarbon with chemical name 2,2,4 Trimethylpentane. It is a colorless liquid that boils at a temperature of 211 degrees Fahrenheit. It defines the 100 point on the octane rating scale.
Isopentane A saturated branch-chain hydrocarbon obtained by fractionation of natural gasoline or isomerization of normal pentane.
Lubricants Substances used to reduce friction between bearing surfaces or as process materials either incorporated into other materials used as processing aids in the manufacture of other products, or used as carriers of other materials. Petroleum lubricants may be produced either from distillates or residues. Lubricants include all grades of lubricating oils from spindle oil to cylinder oil and those used in greases.
Marketable Petroleum Coke Those grades of coke produced in delayed or fluid cokers which may be recovered as relatively pure carbon. This "green" coke may be sold as is or further purified by calcining.
Petroleum Administration for Defense (PAD) Districts Geographic aggregations of the 50 States and the District of Columbia into five districts by the Petroleum Administration for Defense in 1950. These districts were originally defined during World War II for purposes of administering oil allocation. Description and maps of PAD Districts and Refining Districts.
Production Capacity The maximum amount of product that can be produced from processing facilities.
Refinery An installation that manufactures finished petroleum products from crude oil, unfinished oils, natural gas liquids, other hydrocarbons, and oxygenates.
Road Oil Any heavy petroleum oil, including residual asphaltic oil used as a dust pallative and surface treatment on roads and highways. It is generally produced in six grades from 0, the most liquid, to 5, the most viscous.
Short Ton A unit of weight equal to 2,000 pounds.
Sulfur A yellowish nonmetallic element, sometimes known as "brimstone." It is present at various levels of concentration in many fossil fuels.

For definitions of related energy terms, refer to the EIA Energy Glossary.


  • Energy Information Administration, Form EIA-820, "Annual Refinery Report".
  • EIA Forms & Instructions .
  • Background, Survey Methodology and Statistical Details .

  •   Explanatory Notes

  • Hydrogen production capacity includes capacity of hydrogen plants on refinery grounds and operated by the refinery operator.
  • The EIA-820 refinery capacity survey was not conducted for January 1, 1996 or January 1, 1998.
  • Totals may not equal sum of components due to independent rounding.