A
Absolute viscosity:

An observation of liquid’s rate of flow under pressure applied to neutralize density’s influence. This property, sometimes called dynamic viscosity, converts to kinematical viscosity by division. With density ex-pressed in grams/cm, centistokes the units of kinematical viscosity, and centipoises the units of absolute viscosity.

Centipoises/density = centistokes

 

Activity:

The level of catalyst’s ability to do its work. The scale descends from fresh (full capacity right from the box or rejuvenator) to spent (coated, poisoned, or other wise neutralized.)

 

Actual specifications:

The quality reports on a specific parcel of fuel or feedstock. Such specifications do not constitute guarantees on the oil unless the seller says so. But they give a good description of the product available aboard a vessel or in a storage tank.

 

AFRA:

Average Freight Rate Assessments. A monthly estimate of tanker rates issued by London tanker brokers, AFRA, quoted on a Worldscale basis, assists large oil companies’ internal accounting, provides a freight element for some netback deals, and serves other purposes somewhat removed for the daily tanker business.

 

Air Draft:

The distance between the surface of navigable water, such as a channel, and the lowest point on some obstruction above it, a bridge for instance. A ship cannot use a waterway if it needs more vertical clearance than available. This consideration prevents certain tankers from reaching some terminals.

 

Aliphatic:

Straight or branched chain carbon-based compounds. Hydrocarbons which lack carbon-ring structures. Aliphatics includes three kinds of molecules: paraffins, olefins, and a particularly reactive sort called acetylenes, which contain triple carbon-carbon bonds.

 

Alkylate:

A high-quality motor gasoline component made by combining isobutene and propylene or butylene. Butylene alkylate has a particularly high motor octane rating which suits it well for blending lead-free grades of automobile fuel and aviation gasoline. Both butylene and propylene alkylate boil fairly low in the gasoline range. This characteristic makes them good “front-end” octane.

 

Alkylation unit:

A piece of refining equipment that combines isobutane and an olefinic stream, usually butylene-rich, to make motor alkylate.

 

Aniline point:

A specification, quoted in degree Fahrenheit in the USA and Centigrade elsewhere, which reports the aromatics content of a hydrocarbon mixture. This quality consideration indicates the susceptibility of a vacuum gasoil to catalytic cracking because paraffins crack well, but aromatics do not. The higher the temperature the better, since higher temperatures mean less aromatics, hence more paraffins.

 

Antiknock index:

The average of a motor gasoline’s or blending component’s RON and MON (RON + MON)/2, sometimes written (R + M)/2.

 

API Degrees (`API):

The units of API’s density scale.  See below.

 

API Gravity:

A density scale expressed in API degrees. The following formula relates this representation of density to specific gravity:

API = (141.5/specific gravity @ 60`F)-131.5.

AR: American rate. Tanker hire prices according to the American Tanker Rate Schedule. This system applies to voyages which begin and end in US ports. US law (the Jones Act) allows only US-flag ships in this domestic service.

 

Aromatics:

A family of hydrocarbons characterized by a single or multiple ring structure containing unsaturated carbon-carbon bonds. Common aromatics which boil in the gasoline range (benzene, toluene, and xylenes, in particular) have a very high octane rating. Reformers produce high octane blend-stock by making aromatics. The "A" in PONA and N+A stands for aromatics.

 

Ash:

Carbonaceous residue produced by burning crude oil and petroleum products. The industry tests fuels and other hydrocarbon mixtures in order to determine how much of this combustion by-product will form in ordinary use of its products. Refiners and others also use ash yield to deduce the presence of metallic soaps, abrasive solids, and other ash-causing contaminents in hydrocarbon mixtures.

 

Asphalt:

A mixture of heavy carbon-based compounds containing a high percentage of multiple-ring aromatics, many of them involving sulfur, nitrogen, and oxygen atoms. Some folks use the word, asphalt, interchangeably with bitumen, the name of its characteristic constituent.

 

Asphalt cement:

A derivative, nearly or completely solid at room temperature, of certain crude oils. This black, tarry material usually comes from vacuum residue. It has several industrial applications. Pavers heat it to liquid form and mix in gravel to make road surface materials called blacktop, macadam, tarmac, or "asphalt". Builders use it to make and join bricks, to coat roofs, and to form shingles. It glues together various manufactured goods.

 

Asphaltenes:

Complex molecules which reveal their ring-structures by dissolving in aromatic liquids but not in paraffins. These compounds may influence the burning and blending characteristics of residual oils, if present in sufficient concentrations. They contribute to the high melting temperature and adhesion of bitumen and asphalt cement.

 

Assay:

An elaborate laboratory report describing in detail the quality of grades of crude oil. The data presented includes, among other items, density, sulfur, naphthenicity, pour point, viscosity, distillation, and information on the quality of individual fractions. They tell a refiner what products he can make from a specific crude.

 

ASTM:

American Society for Testing and Materials. An organization which determines and publishes consensus standards of suitability and quality for a wide variety of materials including petroleum and refined products. ASTM develops and endorses methods of testing hydrocarbons properties as well as definitive specifications for such classes of refined product as fuel oils, aviation kerosene, burning kerosene, and motor gasoline.

 

Atmos:

Abbreviation of atmospheric-pressure distillation, as in atmos bottoms and atmos gasoil.

 

Atmospheric distillation:

A technique for separating hydrocarbon mixtures which uses distillation apparatus operated at atmospheric pressure. Generally, the industry specifies ambient pressure to distinguish products of crude distillers, atmospheric fractions, from the products of vacuum flashers which, as the name implies distill atmospheric residue in a partial vacuum.

 

Atmospheric gasoil:

The heaviest product boiled by a crude distillation unit operating at atmospheric pressure. This fraction ordinarily sells as distillate fuel oil, either in pure form or blended with cracked stocks. In blends atmospheric gasoil, often abbreviated AGO, usually serves as the premium quality component used to lift lesser streams to the standards of saleable furnace oil or diesel engine fuel. Certain ethylene plants, called heavy oil crackers, can take AGO as feedstock.

 

Atmospheric residue:

The portion of crude oil taken as a bottoms product in a crude distillation unit which operates at atmospheric pressure under several other names apply to this product including atmos (atmospheric) reside, atmos bottoms, atmospheric fuel oil long reside, straight-run heavy fuel oil and topped crude.

 

Availability:

A quantity of crude or product a supplier could sell.

 

Aviation gasoline:

High-grade motor fuel blended to meet the requirements of piston-type aero plane engines. This specialty product differs in all critical respects from aviation turbine fuel (jet).

 

Aviation turbine fuel (ATF):

The fuel burned by aero planes jet engines. Civilian aircrafts consumes a kerosene-range product variously known as jet kero, jet A-1, avtur, DERD-2494, and JP1. Warplanes needed special fuels.  Two military grades, JP-4 and JP-5 fall within the common notion of AFT.

 

Avgas:

Familiar designation of aviation gasoline.

 

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B

 

Backhaul:

A tanker's revenue-producing return voyage. Some ships shuttle between two tankers ports. They travel in one direction as dictated by normal oil flow patterns or refining system's needs. Often, they have no natural employment from when they discharge to their port of origin where another load awaits. They would like to find a cargo to pay their costs on this return trip. Otherwise, they must return in ballast. Charters often relet ships at bargain back haul rates for these voyages. They prefer some income to none.

 

Ballast:

Water taken aboard a vessel to increase its draft, steady its motion, correct its trim, or otherwise make it more seaworthy when sailing without cargo. The trade uses this word to describe repositioning voyages or empty backhauls forced on ship. Hence, phrases appear like "ballasting Trans-Atlantic"

 

Barge lots:

Quantities of petroleum product accommodated in the sizes of barges in common use in a particular area. This term usually applies to small (less than cargo-size) volumes of product intended for regional distribution. On the US Gulf Coast, for instance, petroleum products barges typically range from 10,000 to 50,000 barrels. On the Rhine, barges typically carry lots as large as 1,000 tons.

 

Base stock:

A hydrocarbon mixture which makes up much of the volume of a gasoline blend. Usually such stocks have properties not too far removed from finished fuel because the minor components have to bring the entire blend within accepted limits of gasoline quality. Base stocks in today's US motor gasoline include cat gasoline, reformate, and alkylate.

 

Beam:

The breadth of a ship at its widest point.

 

Benzene:

The simplest aromatic. This unsaturated six-carbon ring forms the basis of a whole class of compounds. The coal processing business first produced benzene in commercial quantities. This source still provides some of the material on the market. But refinery and petrochemical plant reformers, toluene hydrodealkylators, and steam crackers now make most of the supply. The products of benzene range from egg cartons to pesticides to nylon stockings.

 

Bitumen:

Mineral pitch rich in asphaltenes and other complex, high-molecular-weight molecules. These mixtures of heavy hydrocarbons and resins form the base of, and impart adhesive, semi-solid consistency to asphalt cement and tar.

 

Blender:

Someone or some organization which combines various components to produce motor gasoline. The term may accurately apply to refiners for they blend motor fuel from blendstock they produce or purchase. In many cases, however, the word designates gasoline makers who do not refine any crude oil and distinguishes them from the "refiners" who do.

 

Blendstock:

A component combined with other materials to produce a finished petroleum product. The term applies most frequently to motor gasoline ingredients.

 

Boiling range:

The temperature spread between the points where a material starts and finishes evaporating. This term has an abstract usage- naphtha-range, for example. It also has a specific one, such as "naphtha with a 140-350 F range."

 

Bond:

Linkage between atoms which holds together molecules. The basic bond involves two atoms connected by a pair of shared electrons. A double bond requires linkage by two pairs (four electrons). A triple bond puts six electrons between two atoms.

 

Bottoms:

Unvaporized material drawn from the lowest point of a fractionation column.

 

Bromine number:

A measure of the olefins content of a hydrocarbon mixture. In the petroleum intermediates trade, it serves primarily to indicate the presence of cracked stock in a cargo or stream. California air pollution laws also make it an important specification for motor gasoline and blendstocks offered in Los Angeles. As a rule-of-thumb, a mixture's bromine number equals roughly twice its olefin content.

 

BTX:

An abbreviation for benzene, toluene, and xylene.

 

BTX extraction:

A solvent recovery process for capturing benzene, toluene, and xylenes from refinery and petrochemical plant process streams (reformate and pyrolysis gasoline.)

 

Bunkers:

Fuel, usually residue grades, burned by ships' main engines. The most familiar kind, called bunker C may contain a high concentration of sulfur and have a high specific gravity but must meet a viscosity specification which assures free flow at the temperatures vessels' fuel systems can maintain.

 

Burning kerosene:

Kerosene intended for use as domestic stove lamp fuel.

 

Butadiene:

A four-carbon olefin. More precisely, a di-olefin because the molecule has two double bonds. Synthetic rubber production consumes much of the butadiene supply. Smaller amounts find an outlet in high-strength resins manufacturing.

 

Buy/sell:

A swap in which, for accounting purposes or other reasons, company A sells a parcel to company B while B sells a second parcel to A. Each party buys one and sells another.

 

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C

 

Carbon residue:

The solid, impure carbon deposits (coke) left behind by burned hydrocarbon fuels. The industry uses two tests, Conradson carbon (Con Carbon) and Ramsbottom carbon to measure oils' tendency to form such solids.

 

Catalytic cracker:

These refinery units, also widely known as cat crackers and FCC's (for fluid catalytic crackers) or FCCU's, convert heavy distillate, most commonly vacuum gasoil, to lighter fractions. Refiners use them, basically, to break molecules which boil in the heavy distillate range to shorter, more volatile hydrocarbon chains suitable for making motor gasoline.

 

Catfeed:

The charge fed to a catalytic cracker. Common usage generally restricts this term to describing vacuum gasoils.

 

Cat gasoline:

The motor fuel-blending component produced by catalytic cracking units.

 

Cat naphtha:

See CAT GASOLINE. Some refiners could, if their markets made it desirable, hydrotreat cat gasoline to make a naphtha suitable for some use other than motor fuel blending, such as steam cracker feedstock.

 

Centigrade degrees (C):

Also known as Celsius degrees. A temperature scale according to which water boils at 100 and freezes at 0. Centigrade, or Celsius, degrees convert to Fahrenheit degrees by the following formula: (C x 1.8) + 32=F.

 

Centistoke:

The unit, commonly abbreviated cSt, of kinematic viscosity which reports a liquid's resistance to flow in terms of its measured viscosity divided by its density.

 

Cetane index (CI):

An estimated diesel fuel performance rating which relies on samples' API gravity and mid-point

CI=-420.34 + 0.016G2 + 0192G log M

                   + 65.01 (LOG M)2-0.0001809M2

      where G= API gravity and M=mid-point in F

 

Cetane number:

A performance indicator for diesel fuel analogous to the octane rating applied to gasolines. The more paraffinic the gasoil, the higher its cetane number.

 

Cetan rating:

See CETANE NUMBER.

 

Chains:

This term has a chemical and a commercial usage in the oil business. It describes the strands of carbon atoms (carbon chains) fundamental to hydrocarbon molecules. It also serves as a designation for the strings of transactions assembled to settle a period's business in unregulated paper commodities like Russian gasoil.

 

Charge:

See FEEDSTOCK.

 

Charter party:

A document in which a ship owner and a Charterer state their agreement to terms for carriage of cargo.

 

Charterer:

The party who contracts for use of a ship. He can do so for a voyage, a spot charter, or a period, a time-charter.

 

Chemical Carrier:

See PARCEL TANKER.

 

Chlorides:

Chlorine-containing compounds. The oil trade pays most attention to these substances when discussing naphtha. Reformers need a specific amount of chloride on their catalyst to perform properly, any more or any less amounts to poison. Naphtha feedstock containing any significant amount of chlorides upsets the delicate balance and reduces reformat yield.