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A glossary of common terms and abbreviations used in the industry, with links to more in-depth articles on key words

SAF - (Sustainable aviation fuel) a renewable form of jet fuel 

Saharan blend (crude) - a light, sweet crude grade produced in Algeria

Sakhalin blend (crude) - a light, sweet crude grade produced in Russia

Salt - salt crystals that exist naturally in crude oil and must be removed in a desalter) , typically before he crude is fed to distillation

Salt dome - a geologic structure consisting of a deep layer of pure salt

San Joaquin (crude) - a heavy, sour crude grade produced in the US

Santa Barbara (crude) - a light, sour crude grade produced in Venezuela

Sarir (crude) - a light, sour crude grade produced in Libya

Sat gas plant - part of the refinery where refinery gas is processed to remove more valuable heavy components (propane, butane, etc) for product blending or conversion, and the reamining lower-value methane and ethane can then be sent to the refinery fuel system

Saturated - a hydrocarbon molecule that has only single bonds

Saturated gas - refinery gas that contains only saturated molecules (no olefins).  This is refinery gas primarily from distillation units

SCF -  (Standard cubic foot) a common measure of volume for a gas such as natural gas or hydrogen

Scheduling - the process of planning individual movements and operational changes in the refinery

SCOT - a process that treats the off-gas from the sulfur recovery unit (Claus) to remove residual amounts of of sulfur containing hydrocarbons

SDA -  (Solvent de-asphalting unit) a refinery process unit that removes asphaltenes from vacuum resid, producing an asphalt product and a resid that can be used for baseoil manufacturing or cracker feed

SECA -  (Special environmental compliance area) regions of the world where the International Marine Organization has established special low sulfur emission limits for ships

Selective hydrotreater - a hydrotreater that removes sulfur from FCC gasoline

Selectivity -  a measure of the ability of a catalyst to achieve the desired yield of products

Semi-regen reformer -  (SR reformer) a reformer with a fixed bed catalyst that has to be taken out of operation periodically in order to regenerate the catalyst as its activity declines

Senipah (crude) - a very-light, sweet crude grade produced in Indonesia

Separation processes - process units used to split a hydrocarbon stream into its components without changing molecule size and structure

Seriah blend (crude) - a light, sweet crude grade produced in Brunei

Shengli (crude) - a heavy, sour crude grade produced in China

Short residue - the residue from the vacuum unit (vacuum resid)

Shot coke - a type of pet coke produced from a delayed coker that has undesirable properties relative to the standard sponge coke grade.  The irregular structure of shot coke makes it difficult to handle and unacceptable for any specialty coke uses

Siberian light (crude) - a medium, sweet crude grade produced in Russia

Simple capacity - refining capacity that includes little or no conversion capacity

Singapore - a major refining center in Asia and main spot market trading hub for the region

Sirtica (crude) - a light, sweet crude grade produced in Libya

SJV (crude) - (San Joaquin Valley) a heavy, sour crude grade produced in the San Joaquin Valley of Southern California, in the US.

Slack wax - unconverted VGO from a hydrocracker

Slurry -  a highly aromatic resid stream produced by the FCC

Smoke point - a measure of a fuel's tendency to generate smoke when burned

SMR -  (Steam methane reforming) a refining technology commonly used to produce hydrogen in a refinery

Soaker - a drum placed at the front of a visbreaker unit to increase reaction time and reduce reaction temperature, resulting in better yield

Sokol (crude) - a medium, sweet crude grade produced in Russia

Solomon Associates -  the primary provider of operations benchmarking for the global refining business

Solvent - a class of specialty refined products and hydrocarbon streams that are used in extraction processes in the refinery

Solvent deasphalting unit -  (SDA) a refinery process unit that removes asphaltenes from vacuum resid, producing an asphalt product and a resid that can be used for baseoil manufacturing or cracker feed

Solvent extraction -  any refining process unit that uses a solvent to selectively extract a component from a mixture based on differences in solubility of the mixtures different components

Sour - a crude oil grade that has a high sulfur content

Southern Green Canyon (crude) - a medium, sour crude grade produced in the US

SOx -  (Sulfur oxides) compounds formed by the reaction of sulfur with oxygen when a sulfur-containing hydrocarbon is burned

Specialty products - smaller-volume, typically industrial products made by the refinery (eg wax, lubricants, solvents)

Specific gravity -  (SPG) an index used to measure the density of a liquid

Spent catalyst - catalyst that has lost its ability to catalyze the desired reaction

SPG - (Specific gravity) an index used to measure the density of a liquid

Spheroid tank - product storage tanks with spherical shape.  These are used to store very light products such as ethane and ethylene

Sponge coke - the typical grade of coke produced by a delayed coker

Sponge oil

Spot charter - a one-off chartering of a tanker for a single voyage

Spot market - the trade of large physical cargoes or parcels in one-off transactions for near-term delivery

Spot price - the price negotiated for a one-off transaction, typically for prompt (immediate) delivery 

SR reformer - (Semi-regen) a reformer with a fixed bed catalyst that has to be taken out of operation periodically in order to regenerate the catalyst as it's activity declines

SRU - (Sulfur recovery unit) a refinery process unit that converts H2S gas into elemental sulfur that can then be sold as a finished product

St James - a major crude oil storage, trading and transportation hub located in Southern Louisiana in the US

Statfjord (crude) - a light, sweet crude grade produced in Norway

Steam cracker - a petrochemical plant that cracks light hydrocarbons such as ethane, propane and light naphtha to produce ethylene

Steam methane reforming -  (SMR) a technology commonly used to produce hydrogen in a refinery. Also used to produce synthesis gas

Steam plant - A plant in a refinery where process steam is generated using boilers fired by natural gas or residual fuel oil

Still gas - the lightest hydrocarbon stream produced from refinery process units. It is typically comprised of methane and ethane, cut can also have some propane or butane in it

Stove oil - a distillation cut derived from an atmospheric distillation unit primarily comprised of molecules with 14 to 20 carbon atoms

Straight chain - hydrocarbons without either branches or rings

Straight run - any refining hydrocarbon stream that comes directly from distillation without any further processing

Stream day (capacity) -  the maximum throughput that a plant can achieve at a moment in time, ignoring any slow downs or outages for maintenance or operational considerations

Street price - the retail price that consumers actually see and pay when purchasing fuel at a retail station

Sutu den (crude) - a medium, sweet crude grade produced in Vietnam

Suez blend (crude) - a medium, sour crude grade produced in Egypt

Suez canal - a major transportation corridor for both crude oil and refined products, connecting the Mediterranean and Asian markets

Suezmax - a class of medium-sized crude oil tanker, larger than Aframax and smaller than VLCC

Sulfolane - an extraction process for separating aromatics from reformate.  Sulfolane (tetrahydrothiophene 1-1 dioxide) is the solvent used in the process

Sullum Voe - the primary loading point for cargoes of Brent crude oil in the North Sea, and the location for FOB price quotes for Brent

Sulfur (quality)  - a contaminant commonly found in crude oil and petroleum products

Sulfur (product) - a major by-product of oil refining and gas processing

Sulfur pile - the inventory of solid, elemental sulfur that builds up at a refinery sulfur plant as H2s is converted to elemental sulfur

Sulfur plant -  refinery plant that converts H2S gas into elemental sulfur that can then be sold as a finished product

Sulfur recovery unit - (SRU) refinery plant that converts H2S gas into elemental sulfur that can then be sold as a finished product

Sulfuric acid -  (H2SO4) a catalyst used in the alkylation process and a product made from the sulfur recovered by refiners

Support process units - supporting units providing utilities and other services in a refinery

Sustainable aviation fuel - (SAF)  a renewable for of jet fuel

Sustaining capital - the ongoing (yearly) capital investment that a refinery must make to continue to operate

Swap - a forward transaction in the over the counter (OTC) market, directly between two parties

Sweet (quality) -  a crude oil grade is called sweet if it has a low sulfur content

Sweetening - any process unit designed to reduce the sulfur content of a stream.  This includes hydrotreating and some solvent extraction processes

Swing cut - the volume of crude where two fractions over lap, which can be "swung" into one or the other fraction (or divided between them) by adjusting the cut point

Synbit - an unconventional crude grade produced by mixing synthetic (upgraded) crude with raw bitumen

Syncrude sweet premium (crude) - (SSP) a medium, sweet crude grade produced in Canada

Synthesis gas - a mixture of carbon monoxide and hydrogen used as a feed into synthesis reactions such as the Fischer-Tropsch process or methanol production

Synthetic feedstocks - crude-like feedstock to a refinery that is produced by through a synthesis process such Fischer-Tropsch

Synthetic lubricants - lubricants that are made from base oils that have been through a conversion process such as hydrocracking or GTL synthesis

Syrian heavy (crude) - a heavy, sour crude grade produced in Syria

Syrian light (crude) - a light, sweet crude grade produced in Syria