A glossary of common terms and abbreviations used in the industry, with links to more in-depth articles on key words
Absorption - a type of separation process used in refining in which a component in a mixed stream is selectively taken up by a liquid stream (absorbed), separating it from other components in the mix
Absorbent - the liquid stream used in an absorption separation process to take up the component being separated
Acid gas recovery - a refining process unit that extracts H2S from the other refinery gas components using an amine as a solvent
Acid number - a measure of the corrosiveness of a crude oil due to the presence of acids, particularly naphthenic acids
Acid regeneration - a process unit that regenerates spend acid (usually sulfuric acid in a refinery) for re-use
Additives - chemicals that are added to refined products in very small volumes to improve the product properties without adding volume
Adsorption - a refinery separation process that uses a solid medium to extract a component from a mixture
Adsorbent - a solid material used to in an adsorption separation process to extract a component from a liquid or gas mixture
ADU - (Atmospheric distillation unit) the first step in the the refining process, in which crude oil is separated into its components (or distillation cuts) for further processing by other processing units
Advanced process control - (APC) a system employed in refining process units to set process conditions based on automated monitoring and evaluation of process conditions and a computer-based determination of optimal conditions
Aframax - a class of oil tanker of medium size, larger than a Panamax and smaller than a Suezmax
Agbami (crude) - a light, sweet crude grade from Nigeria
AGO - (atmospheric gasoil) a distillation cut derived from an atmospheric distillation unit in the diesel range, primarily comprised of molecules with 14 to 20 carbon atoms
AKI - (anti-knock index) a measure of gasoline octane that attempts to capture both the measure of road octane and motor octane in one number
Akpo (crude) - a light sweet crude grade from Nigeria
Al Shaheen (crude) - a medium, sour crude grade from Qatar
Alcohol-to-jet - (AtJ) a renewable fuel process that makes jet fuel from a renewable alcohol
Alky - a refining conversion unit that produces a high-quality gasoline blendstock by combining two LPG-range molecules to form one gasoline-range molecule
Alkylate - the primary product of the alkylation unit, which converts light olefins (such as butylene) into a high-quality gasoline blendstock by reacting it with isobutane
Alkylation - a refining conversion unit that produces a high-quality gasoline blendstock by combining two LPG-range molecules to form one gasoline-range molecule
Alvheim (crude) - a medium, sweet crude grade produced in Norway
Amenam (crude) - a light, sweet crude grade from Nigeria
American Petroleum Institute - (API) an industry organization for the US oil industry that lobby's for the industry on policy issues and also sets some industry standards
Amine - a category of process chemicals used in refining to extract acid gases such as H2S from refinery gas (see DEA, MEA)
Amine unit - a refining process unit that extracts H2S from the other refinery gas components using an amine as a solvent
Ammonia - (NH3) ammonia is a petrochemical product and a proposed alternative fuel for shipping
Ammonia plant - a process unit that produces ammonia from hydrogen and atmospheric nitrogen using the Haber-Bosch process
Amna (crude) - a light sweet crude grade from Libya, in North Africa
Aniline point - a measure of the paraffinicity of a stream, and thus its ignition quality when used as a diesel blendstock
Anode grade coke - a high-quality, specialty grade of pet coke used to make anodes for the aluminum and steel industries.
ANS (crude) - a medium API sour crude grade produced in Alaska
Anti-knock index - (AKI) a measure of gasoline octane that attempts to capture both the measure of road octane and motor octane in one number
APC - (advanced process control) a system employed in refinery process units to set process conditions based on automated monitoring and evaluation of process conditions and a computer-based determination of optimal conditions
API - (American Petroleum Institute) an industry organization for the US oil industry that lobby's for the industry on policy issues and also sets some industry standards
API Gravity - a commonly used index of the density of a crude oil or petroleum products
ARA - a refining hub market comprised of the ports of Amsterdam, Rotterdam and Antwerp in Northwest Europe
Arab extra light (crude) - a light, sour crude grade produced in Saudi Arabia
Arab heavy (crude) - a heavy sour crude grade produced in Saudi Arabia
Arab light (crude) - (ARL) a medium gravity, high-sulfur crude grade produced in Saudi Arabia
Arab medium (crude) - a medium, sour crude grade produced in Saudi Arabia
Arab super light (crude) - a very light, sweet crude grade produced in Saudi Arabia
Arbitrage - a market condition where the difference in two prices creates an opportunity to make a profit through trading
Arctic diesel - a special grade of diesel for use at low temperatures
Ardjuna (crude) - a light, sweet crude grade produced in Indonesia
Asgard (crude) - a very-light, sweet crude grade produced in Norway
Attaka (crude) - a light, sweet crude grade produced in Indonesia
ARDS - (Atmospheric resid desulfurization) a refining process unit used to lower the sulfur content of resid streams
Argus - one of the major oil price reporting agencies (PRAs) and industry news services for crude and refined products (along with Platts)
Argus sour crude index - (ASCI) a spot market price assessment for medium sour crude in the US Gulf Coast market. It is used as a marker for grades such as Mars and Poseidon
Aromatics (content) - hydrocarbons containing a benzene ring of six unsaturated carbon atoms
Aromatics (products) - refined products that are comprised mostly of hydrocarbons containing a benzene ring of six unsaturated carbon atoms (eg Benzene, Toluene, Xylene)
Aromatics extraction - a refining process unit that uses solvent extraction to remove aromatics from vacuum gasoil in order to make base oil
ASCI - (Argus sour crude index) a spot market price assessment for medium sour crude in the US Gulf Coast market. It is used as a marker for grades such as Mars and Poseidon
Aspen Tech - a refining industry software firm that is best know in the downstream oil industry for its planning and scheduling tools, especially the PIMS LP model
Asphalt (product) - the highest-density liquid refined product produced by a refinery, used for road construction and building materials
Asphaltenes - large, high-density molecules found in the heaviest distillation fractions of crude oil
Asphalt plant - a refining process unit that extracts asphaltenes from vacuum resid for use as asphalt cement
Assay - a detailed chemical analysis of a crude oil that describes the volumes and qualities of different refined products that will result from processing the crude through a refinery
Associated gas - natural gas that is produced along with crude oil, and typically separated from the oil at the well head
ASTM - (American society of testing and measurement) a standards organization (like ISO) that sets quality standards and defines testing methods for petroleum products
Atmospheric tower bottoms - (ATBs) the heaviest of the distillation cuts out of the atmospheric distillation tower. Typically sent to the vacuum unit for further separation into VGO and Vac resid
Atmospheric distillation unit - (ADU) the first step in the the refining process, in which crude oil is separated into its components (or distillation cuts) for further processing by other processing units
Atmospheric gasoil - (AGO) a distillation cut derived from an atmospheric distillation unit in the diesel range, primarily comprised of molecules with 14 to 20 carbon atoms
Atmospheric resid - (AR) the heaviest of the distillation cuts out of the atmospheric distillation tower. Typically sent to the vacuum unit for further separation into VGO and Vac resid
Atmospheric tower - (AT) the first step in the the overall refining process, in which crude oil is separated into its components (or distillation cuts) for further processing by other processing units
ATR - (Autothermal reformer) a process unit that produces hydrogen from natural gas
Availability - the processing capacity of a refinery or individual processing unit that is actually available to be used, as opposed to the name plate or design capacity
Aviation gasoline - (Avgas) a gasoline-range refined product that is used in air craft, especially smaller air craft. The more common fuel for large aircraft is jet fuel.
Avgas - (Aviation gasoline) a gasoline-range refined product that is used as an air craft fuel, especially in smaller air craft. The more common fuel for large aircraft is jet fuel
Azeri light (crude) - a medium, sweet crude grade produced in Azerbaijan