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 a 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 otherwise 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 butylenes. Butylenes alkylate has a particularly high motor octane rating which suits it well for blending lead-free grades of automobile fuel and aviation gasoline. Both butylenes 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
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 contaminants 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
AVGAS
Familiar designation of aviation gasoline
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.
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.
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.
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.
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
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 RATING
See CETANE NUMBER.
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.
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.
CLEAN
Unleaded, when used to describe motor gasoline or blendstock.
CLOUD POINT
The temperature where wax crystals begin to appear in a cooled hydrocarbon mixture. This quality consideration, usually applied to gasoil, indicates how cold the air must become to make a stream form solids which block filters halting fuel delivery. Cloud point of gasoil resembles freezing point of kerosene.
COA
Contract of affreightment. An arrangement between a ship owner and a charterer for the carriage of a certain amount of specified grade or grades of cargo on named routes over a period of time. Owners may use any suitable ships at their disposable to meet the contract's requirements.
COILED
Tankers fitted with tubes which carry hot water or steam through viscous cargoes, such as heavy fuel oil and certain crudes, to keep them fluid.
COKE
Solid, almost hydrogen-free carbon made on purpose in fuel oil destruction units called cokers or inescapably in other processing hardware. Coke forms on the catalyst in cat crackers and in the furnaces of ethylene plants. The coke manufactured intentionally may go to the graphite industry if it meets certain quality requirements. Otherwise it sells as solid fuel. The incidental accretions require removal to keep process units efficient.
COLD BLENDER
See blender. European producers of motor gasoline who have no distillation or other refining equipment go by this name. They make their product by mixing purchased "cold" components. This term has the advantage over the simple "blender" used in the USA of emphatically distinguishing a certain group of low-capital motor fuel makers from the refinery-based gasoline producers who also, of course, blend streams to obtain their finished products.
COLD FILTER PLUGGING POINT
A measure of diesel fuel's suitability for use in cold weather. Usually called by its initials, CFPP, this specification reports the temperature where clotted wax stops fuel from passing through a test filter. CFFP goes beyond cloud point, which indicates where the cause of problems appears. It tells the fuel temperature where real trouble, like a stalled truck, happens.
COLONIAL GRADE
Light petroleum product which conforms to one of the specifications of Colonial Pipeline Company.
COLONIAL PIPELINE
The on-land pipeline system connecting US Gulf Coast refineries to Southeast and Atlantic Coast markets. The main artery runs from Deer Park, Texas, to Linden, NJ. It has the effective capability to carry roughly 2.1 million barrels per day of clean products, including gasolines, home heating oils, diesel fuels and kerosene's. The system serves more than 280 petroleum-marketing terminals in thirteen states. Specifications required to move motor gasoline and No. 2 oil through the Colonial pipeline have become the quality standard for cargoes of these products imported on the US East Coast. Transporting a gallon of gasoline from Houston, Texas, to the New York harbor area via the Colonial pipeline costs about 2.3 cents. Moving product through roughly 1,550 miles of pipeline typically takes three to four weeks.
COLOR
A spectrum which extends from absolutely colorless (usually described as water white) to dirty (black and opaque). This property only pertains usefully to light refined products and gas liquids. It makes a handy indicator of contamination or poor distillation for very pale substances such as naphtha and undyed motor gasoline. The industry uses several scales to report color including Saybolt and ASTM.
COMBINATION CARRIERS
Vessels fitted to transport more than one type of cargo. The petroleum industry uses a good-sized fleet of OBO's, ships which transport dry cargo or oil.
COMPATIBILITY
The suitable of two or more residues for blending. Some stocks--certain visbroken resides and hydrotreated bottoms, for instance--do not combine well enough to yield stable fuel oils.
COMPONENT
One part of a blend. The word most commonly names streams combined to make motor gasoline. In that usage, it serves as short version of "mogas component". Though not used casually, "gasoil component," "heavy fuel oil component" and similar designations make perfect sense.
CONDENSATE
Natural gas liquids heavier than butane. The term condensates commonly covers two quite different kinds of streams: natural gasolines and heavy condensates. Natural gasolines come from LPG or LNG plants. They have properties similar to naphtha's. Heavy condensates resemble very light crude oils. Sometimes called field condensates, they come from gas/oil separation plants which process the raw stream from a gas field. Since they come as a by-product of gas production, much as associated gas comes as a by-product of crude production, associated crude suits them as a description.
CONRADSON CARBON (CONCARBON)
A measurement of hydrocarbon mixtures tendency to leave carbon deposits (coke) when burned as fuel or subjected to intense heat in a processing unit such as a catalytic cracker. The ConCarbon test involves destructive distillation -subjection to high temperature which causes cracking, coking, and drives off any volatile hydrocarbons produced--and weighing the residue which remains. A somewhat similar test, Ramsbottom carbon, also measures mixtures tendency to form coke. For reasons of laboratory convenience, analysts ordinarily restrict the Ramsbottom method to hydrocarbons which flow 90 C. To obtain a useful indication of carbon residue formation by light distillates, such as high-speed diesel, the industry often measures coke formation by the last 10 percent of the material to boil. This technique goes by names such as "ConCarbon residue on 10 percent bottoms."
CONTRACT DEAL
See TERM DEAL
CONVERSION
Cracking molecules which boil above the threshold temperature into smaller ones which boil below it. Traditionally, the term applied to catalytic crackers. They convert oil which boils above 430 F to hydrocarbons which boil below that point. In other words, they convert gasoil to naphtha. The recent popularity of residue crackers has established another conversion standard around 720 F. This point marks the elevation of fuel oil to light products. Loosely, the term refers to any processing step which breaks molecules into pieces which boil at lower temperatures.
CO-PRODUCTS
Substances made in one processing unit at the same time. A lot of refining hardware, especially crackers, cannot help making an assortment of hydrocarbons. The industry uses "co-product" when it does not want to designate one material a plant's product and demean the rest by calling them by-products. Its name gives a good clue why an ethylene cracker gets built. But petrochemical companies call the other olefins and the aromatics it makes its co-products.
COW
Crude oil wash. A cleaning technique used by some ships. They spray a few tons of crude around their tanks to rinse off the remains of previous cargoes. This method cannot make a dirty vessel clean. But it can do enough good to prevent excessive darkening of not particularly color-sensitive cargo.
CRACKED
Broken by a thermal or catalytic process. This term frequently describes an oil product which contains cracked components made by such a process.
CRACKED COMPONENT
An ingredient in a hydrocarbon blend produced by a cracking process. The opposite of a virgin or straight-run component. Blends containing any cracked components do not qualify as straight-run. The presence of cracked components makes refinery streams unsuited for certain feedstock uses. The issue arises most frequently regarding heavy fuel oils. Companies buying such streams to produce catfeed want a virgin material containing no cracked components.
CRACKED CUTTERS
Cycle oils used to reduce the sulfur content or, especially, the viscosity of fuel oil.
CRACKED FUEL
Fuel oil containing molecules broken in a cracking unit. The term most frequently applies to residue. It distinguishes streams unsuitable for upgrading from straight-run material of interest as feedstock.
CRACKED GAS
See UNSATURATED GASES
CRACKED NAPHTHA
General term for any naphtha-range fraction produced by a molecule breaking process. The category includes cat gasoline from a catalytic cracker, visbroken naphtha from a visbreaker, and coker naphtha from a coking unit. In ordinary usage, this term signifies streams with a high olefin content. That custom discourages its application to hydrocrackate and pyrolysis gasoline, known, respectively, for their naphthenes and aromatics concentrations.
CRACKED STOCK
See CRACKED COMPONENT. Cracking units produce cracked stocks such as cycle oils and cat naphtha's used for blending finished products.
CRACKER
A processing unit which breaks molecular bonds, usually to produce lighter hydrocarbons with lower boiling points. Commercial crackers (cracking units) include cat crackers, hydrocrackers, thermal crackers, visbreakers, and stream crackers.
cSt
Abbreviation of centistoke.
CUT
To divide a hydrocarbon mixture into fractions by distillation. Also a name for the fractions obtained, as in kerosene cut or naphtha cut.
CUTTER (CUTTER STOCK)
A refinery stream used to thin a fuel oil or gasoil. Viscosity reduction and sulfur level adjustment provide most of the requirement for the cutter.
CYCLE OIL
Cat cracking unit produced in the fuel oil or gasoil boiling range. The term light cycle oil generally describes products of this kind suitable for blending into diesel or home heating oil. Heavy cycle oil, accordingly, refers to the cat cracked material which boils at temperatures in the fuel oil range.
DEADWEIGHT TONNAGE (DWT)
The standard measure of ships' carrying capacity. The trade usually abbreviates this term to speak simply of tankers "deadweight." This specification reports total weight, usually in long tons, of fresh water, stores, bunkers, and cargo a vessel can carry. For oil tankers, cargo averages 95 to 96 percent of the total.
DELAYED COKER
A coking unit (coker) which provides a drum where heated molecules crack and coke forms.
DEMURRAGE
The cost of delaying a ship. Busy channels, occupied berths, commercial considerations, lack of shore tankage, pumping limitations, and a host of other eventualities related to how or where a charterer uses a vessel can prevent it from loading or unloading promptly. When they do, the ship's owner charges for a waiting time.
DENSITY
A description of oil by some measurement of its volume to weight ratio. The industry usually relies on two expressions of oil's volume-weight relationship-specific gravity and API degrees. The larger a specific gravity number and the smaller an API number, the denser the oil.
DISTILLATION CURVE
The boiling temperature distribution of a material's component molecules. Tests report this characteristic as temperature at which various percentages of a sample have boiled or as the percentages which have boiled at various temperatures.
DISTILLATION UNIT
Separation equipment that heats a mixture and divides its ingredients according to the temperature where they boil.
DISTILLER
See DISTILLATION UNIT. A term most often used as shorthand for "crude oil distillation unit."
DISTRIBUTORS
Inland wholesalers.
DOCTOR TEST
An indicator to detect the presence of significant amounts of mercaptan sulfur in light hydrocarbon mixture. Materials passing this test carry the designation, "Doctor negative." Doctor negative stocks have sufficiently low mercaptan levels for use in motor gasoline. Doctor positive materials do not necessarily have too much mercaptan, but may require a more quantitative test.
DOWNSTREAM
A relative term, which indicates greater removal from origins than some point of reference. For example, a petrochemical plant which cracks naphtha lies downstream from a refinery. Money made by marketing products constitutes downstream profits compared to earnings on crude sales. The opposite of upstream.
DPK
Dual-purpose kerosene. Product suitable for use as burning kerosene and aviation turbine fuel.
DRAFT
The distance between a ship's keel and waterline. The lowest part of a vessel lies this far below the surface of the water. Every ship's draft changes with the amount of cargo aboard it, its trim and the temperature and salt content of the water in which it floats. A ship reaches its deepest draft when fully laden in warm fresh water. The shipping industry calls that distance "tropical fresh" or "TF" draft. "Fresh" (F),"tropical"(T), "summer" (s), and "winter"(W) report increasingly shallow drafts for a vessel; reflecting denser and denser water.
ELASTOMER
A polymer that forms a disorganized molecular pile capable of uncoiling and recoiling in response to physical force and its removal. This ability to yield and recover makes a substance rubbery. Industry turns molecules into flexible, stretchable, compressible, resilient goods.
ENGLER
A not particularly popular method of measuring and reporting viscosity.
EQUITY HOLDERS
Companies entitled to some portion of an oil field's production due to their investment in its development. See producers.
ETHYLENE
Two-carbon olefin used to make plastic films, fibers, molding compounds, and other products.
ETHYLENE PLANT
See STEAM CRACKER.
FAHRENHEIT DEGREES (F)
A temperature scale according to which water boils at 212 and freezes at 32 Fahrenheit degrees convert to Centigrade degrees (C) by the following formula: (F-32)/1.8= C.
FBP
Final boiling point.
FEEDSTOCK
A product of oil or gas processing suitable for charging to (introduction into) an upgrading unit for further refining or transformation. In general, each stage of hydrocarbon processing regards the material, it receives for alteration as its feedstock and what it makes of that material as it product. A reformer, for instance, takes naphtha as its feedstock and yields reformat, its product. Reformate, in turn, serves as the feedstock for an aromatics extraction unit which isolates benzene, its product. The feedstock business deals in those partially refined petroleum streams (intermediates) and gas plant products processed by refinery units and basic petrochemical plants.
FINAL BOILING POINT
The temperature where a natural material or fraction finishes boiling. This temperature also goes by the name, end point. Some folks use the phrase " full boiling point." This expression has fallen into disfavor, though. It implies complete evaporation of the material in question--a degree of perfection not ordinarily achieved, or even sought, in the industry's laboratories and commercial facilities.
FINISHED GASOLINE
Motor gasoline which meets the merchantability standards of a particular market. These specification fuels differ from blendstocks called gasoline which require the addition of other components to make it fit for retail sale in one country or another.
FINISHING COMPONENT
Ingredients added to gasoline blends in small amounts to adjust the mixture to motor fuel standards. Finishing components include toluene and MTBE.
FIRM INDICATION
A suggestion from a prospective buyer or seller feeling his way toward a possible deal. Firm indications carry more weight than the initial indications casually given in routine conversation. But they do not constitute an offer. They show distinct interest but do not carry any specific obligations.
FIX
When a ship-owner and charterer make a deal, they say they have "fixed" a ship. They have settled all of the issues including the price, to employ the vessel.
FIXED PRICE
The oil trade speaks of prices quoted in absolute figures, like $157 per ton and 44.875 cents per gallon, as fixed prices these numbers, and the transactions (called fixed-price deals) which use them, do not move with any price business in recent years
FLASH POINT
The temperature at which a hydrocarbon releases vapors in sufficient quantity to permit combustion.
FLASHER
See DISTILLATION UNIT
FLEXIBILITY
The degree to which a processing unit can make a desired product from various feed stocks. The term applies particularly to steam crackers. Some such plants can produce ethylene from a range of hydrocarbon streams spanning ethane to vacuum gasoil. Other units have less flexibility.
FLOATING PRICE
A price tied to some sensitive reference quotation. The oil business took this approach when market volatility made fixed-price deals too risky. In the late 1980's the majority of crude and products deals which involve any substantial time exposure use market-linked prices. One grade of crude floats with published quotes for another. Feedstock floats with finished products. Fuel sold in supply regions float with price levels at consumption points. Physical material floats with price levels at consumption points. Physical materials floats with futures exchange reports. And so forth.
FLUID COKER
A coking unit (coker) which makes coke in powdery, free-flowing form.
FLUX
Rate of material flow. Some refiners use this word when discussing the fluidity or viscosity of petroleum products, particularly heavy ones.
FLUXANT
Rate of materials flow faster or at lower temperatures.
FRACTIONATING TOWER
Distillation column.
FRACTIONATION
Division of a hydrocarbon mixture according to the boiling temperature of its component molecules. This general term describes both distillation, which puts heat into mixtures to separate them, and cooling techniques which work by heat removal.
FRACTIONS
Part of a hydrocarbon mixture isolated according to the temperature where it evaporates. Distillation units ordinarily divide a combination of liquid hydrocarbons, such as crude oil or the output stream of a cracker, by sorting its molecules into portions with different boiling ranges. These parts, or fractions, also go by the name, cuts. The bottom and top temperatures of a fraction sometimes serve as its designation, as in 180-330 fraction.
FREEZING POINT
The temperature where aviation kerosene must remain free of wax crystals. These particles can clog jet engine fuel filters and nozzles. This specification, therefore, indicates the suitability of kerosene for propelling airplanes into the cold air at high altitudes.
FUEL BLENDING
Mingling two or more materials, refinery streams ordinarily, to make a mixture that meets a grade of fuel's legal and commercial requirements. Refineries almost always sell finished products made from more than one component. Modern motor gasoline, for all practical purposes, must comprise several blendstocks. No single material can meet all its various specifications. Kerosene and gasoline do not require blending the way mogas does. But refinery economics and the number of processes which yield middle distillate fractions make combinations quite probable. Heavy fuel oil usually includes several streams in order to concoct a saleable material from the dregs of assorted units.
FULL-RANGE NAPHTHA
See WHOLE NAPHTHA.
FUNGIBLE
Marketable product. Typically refers to petroleum products moved by pipeline. As long as a particular grade of gasoline meets Colonial pipeline specifications, for instance, it may travel and trade as fungible product. A fungible batch in the Colonial system consists of 25,000 barrels or more of material from various suppliers, all of which meets the specifications published by the Pipeline company.
FURNACE OIL
A term ordinarily reserved for the kind of gasoil used for household heating. The quality of this product can vary from place to place. The USA, for instance, uses a lighter distillate for this purpose than do some European countries.
GAS PLANT
Facilities, which remove liquids from natural gas streams, bear this name. So do processing units in refineries which fractionate the light ends distilled from crude or produced by cracking and other upgrading equipment. In both cases, the plant separates C3 and heavier materials from fuel gas. Some of this hardware cuts as deep as C2. Complex refineries usually have two gas plants. One, the saturates gas plant, handles paraffinic, straight run light ends. The other, the unsaturated gases plant, takes care of olefinic gas streams which come from crackers.
GASOIL
A refined petroleum product denser than motor gasoline and kerosene but lighter than residual oil. This hydrocarbon mixture has two common uses: fuel for furnaces and for small diesel engines. It gets several popular names from these applications, including diesel and furnace oil. The phrase distillate fuel distinguishes gasoil from heavier mixtures used in large burners and large, slow diesel engines. The trade frequently shortens this term to distillate. ASTM's designation, No. 2 oil, serves as the primary name for gasoil in some parts of the world, especially North America. The refining industry employs "gasoil" To name certain intermediates in addition to familiar finished fuels. These special usages generally attach, or assume and adjective which indicates the source of the intermediate, such as atmospheric gasoil, vacuum gasoil, coker gasoil, pyrolysis gasoil, and so forth.
GASOLINE EXTENDER
A component in motor gasoline blend added exclusively for volume. Ethanol, for example, often has this limited function in the USA.
GRADE TRADE
A swap of one kind of oil for another. Such business involves exchanges like sour crude for sweet and gasoil for gasoline.
GRAVITY
The density or weight to volume ratio of materials. The oil business usually expresses this quality in API degrees or specific gravity.
GSP
Government selling price. The price of crude or products established by a government marketing company. Sometimes written GEP, for government established price. See posted price.
GUARANTEES
A seller promises to deliver oil at least as good as the guarantees--guaranteed specifications--he puts on it. When material sells on guarantees, the buyer can refuse to accept it, or demand a price adjustment, if it fails to meet any of them.
HANDY-SIZED VESSEL
A tank ship suited to tie up at a T2 type pier. The mooring capacity of such berths restricts vessel length (LOA) to a maximum of 560-600 feet. In modern ship designs, this LOA allows a deadweight tonnage slightly exceeding 30,000. Such a tanker defines the limit of a handy-sized cargo.
HEART CUT
A distillation fraction restricted to a narrow range to meet specific needs. The navy, for instance, buys a heart cut of ordinary jet kero known as JP-5.
HEAVY CONDENSATES
See CONDENSATES.
HEAVY FUEL OIL
A dense, opaque petroleum derivative made from the unboiled material, the bottoms or residue, from crude vacuum distillation units plus, perhaps heavy product from crackers. Blends made to meet market or specific customers standards often also include quality improvers called cutter. Material marketable for burning fits the Number 6 (No. 6) oil description in ASTMD 396. Ships consume a good portion of the No. 6 oil produced around the world. Seafarers customarily call their vessels fuel bunkers. Some people use that name for all heavy fuel oil.
HEAVY LIQUIDS CRACKER
An ethylene plant equipped to crack naphtha's or gasoil's.
HEAVY NAPHTHA
A naphtha cut with a boiling range which commonly extends from the end of the light naphtha range (300-400 F, depending on the intentions and needs of the refiner). See naphtha.
HEAVY OIL CRACKER
A variety of catalytic cracker designed to process straight-run fuel oil instead of vacuum gasoil.
HIGH POUR
A description of distillate or residual fuel oils which do not flow at unusually low temperatures. Often, the term designates ordinary product and distinguishes it from material with uncommonly good cold properties.
HIGH-SPEED DIESEL
Distillate fuel oil suitable for powering compression ignition engines operated above 1,000 RPM. Diesel of this quality fits ASTM classifications No. 2-D. Light-duty engines such as those which power trucks, buses, portable electricity generators, small boats, and some locomotives, burn this grade of fuel.
HYDROCARBON
A molecule composed entirely of carbon and hydrogen atoms. The industry usually includes sulfur and metals compounds which naturally occur in crude oil in casual uses of the word. Gasoline blending and marketing rely on the strict definition to exclude oxygen-containing substances such as alcohols and ethers.
HYDROCRACKATE
Naphtha-range product of a hydrocracking unit. Many refineries divide this stream into a light cut suitable for motor gasoline blending and a heavy one which makes excellent reformer feedstock.
HYDROCRACKER
Refinery units which use a catalyst and extraordinary high pressure, in the presence of surplus hydrogen, to shorten molecules. This process can crack a variety of hydrocarbons. It might change atmospheric gasoil to naphtha or reduce naphtha to LPG. In most cases, though, refiners use it to convert vacuum gasoil to high quality middle distillate. In periods of strong motor gasoline demand, high severity operations can emphasize production of naphtha, called hydrocrackate, instead of diesel and kerosene.
HYDRODEALKYLATION (HDA)
Substitution of hydrogen for a hydrocarbon group in a molecule. Refiners most frequently apply the term to processing units which turn toluene into benzene.
HYDROSKIMMER
A refinery more complex than a topping plant by virtue of having a reformer. That piece of equipment, in addition to making high octane motor gasoline blendstock, yields hydrogen. Even a fairly basic refinery can often use that by-product to improve the quality of its products. Hydroskimmers do not have cracking units.
HYDROTREATING
Purification process which uses hydrogen to displace sulfur and metal contaminants from partially refined oil. The process also reduces olefins and aromatics concentrations by saturating multiple bonds. Such clean-up work prepares process intermediates for upgrading units and blend stocks for specification fuel pools.
IBP
Initial boiling point.
IGS
Inert gas system. If tank ships let air fill their tanks as they pump out oil, an explosive mixture of hydrocarbon vapor and oxygen can form. Any spark, such as static electricity, could cause catastrophe. To eliminate this danger, modern vessels vent their tanks with gas which will not support combustion. Some use oxygen-depleted exhaust from the ship's engines. The most sophisticated systems fill empty space in tanks with nitrogen.
ILLUMINATING KEROSENE
See BURNING KEROSENE.
INDEPENDENT SURVEYORS
The inspection and testing organizations hired by petroleum companies to determine how much and what quality of oil changed hands in performance on a deal. In the interest of impartiality, buyers and sellers usually share the cost of inspections.
INDICATION
A suggestion given by a prospective buyer or seller of what he might do. Indications imply no commitments. At this level of discussions, folks can change their minds without serious consequences.
INITIAL BOILING POINT
The temperature where a natural material or fraction begins to boil.
IN-LINE BLENDING
The practice of pumping various motor gasoline components from their individual storage tanks into a single pipe and mixing them in the process. Gasoline made in such fashion generally is intended for bulk in shipment. Typically it flows directly aboard a vessel after blending. Refiners with limited capability to store a particular grade of gasoline frequently use this method.
INTEGRATED OIL COMPANIES
Organizations which find, produce, transport, and refine oil, and market oil products. Less complete enterprises concentrate on a part of this sequence. The industry calls its largest integrated companies the majors.
INTERMEDIATE
A partially refined petroleum stream. Such materials require further processing to make finished products. Various intermediates sell as feedstocks. The industry also uses this word as an adjective to designate a medium score on some quality ranking--between sweet and sour, for instance.
INTERMEDIATE CRUDE
Petroleum with sulfur content between sweet and sour--often defined as between 0.5 and 1.0 weight percent sulfur.
ISOMER
One of two or more compounds of the same type and chemical formula but different configurations. For example two C4 paraffins, isobutane and normal butane have the same number of carbon and hydrogen atoms. But the carbons form a T shape in one and a straight line in the other. This difference gives each of the two isomers its own properties and uses.
ISOMERATE
The motor gasoline blendstock made by a C5-C6 isomerization unit.
ISOMERIZATION
A process which forces one isomer to become another. The most common application in the oil industry involves twisting linear paraffins into branched-chain form. Many refiners turn into isobutane, and a normal pentane/ hexane stream into an isopentane/isohexane mix. Some petrochemicals producers use an isomerization process to make para-xylene as possible from mixed xylenes.
ISOPARAFFINS
Branched-chain saturate hydrocarbons. Any paraffin composed of four or more carbon atoms can have one or more isoparaffinic isomers.
JET
A nickname for kerosene-range aviation turbine fuel. A somewhat longer expression, jet kero, also enjoys wide popularity as a substitute for the formal designation.
JET A-1
ASTM's designation for the most common grade of aviation turbine fuel.
JET KERO
A shortened version of "jet kerosene." See aviation turbine fuel.
JP-4
Jet B. A common grade of military jet fuel. The industry habitually calls this product naphtha-type jet because it has a lower boiling range than civil jet kero.
JP-5
A heart cut of jet A-1 favored aboard aircraft carriers for its high flash point.
KEROSENE
A petroleum product which boils between naphtha gasoil. This cut's distillation range can vary to accommodate other products. Many refiners want to take naphtha as high as 350 or 375 F. In those cases, the kerosene cut has a rather high initial boiling point. Many crudes permit a good quality kerosene to start as light as 320 -330 F. For some crudes, kero's final boiling point might come as low as 450 F while for others it may exceed 500 F. Aviation turbine fuel, jet gives kerosene a large outlet. Household heating and illuminating markets also consume kerosene.
KINEMATIC VISCOSITY
A measure of liquid's rate of flow under gravity. The standard test of this property determines the time a sample of material requires to drain through a laboratory vessel.
KNOCKING
Pre-ignition. If the gasoline/air vapor in a motor's cylinders is too compressed, the heat produced will cause it to ignite without the aid of a spark. This uncontrolled combustion probably will not occur at the ideal moment to transfer energy and promote rotation of the crankshaft. In audible cases, the exploding fuel charge expands against a rising piston creating vibrations and an accompanying rattle.
LAYCAN
The period when a spot chartered ship must arrive to load a cargo. The word combines "laydays" and "cancellation" as does the concept. Charter parties specify a range of days when the terminal will receive the ship which corresponds to the laydays of the stem. This period ends with the last moment a ship can give notice of readiness to berth and lift a cargo within its laydays. If the tanker does not arrive by that point, the charterer usually has several options including cancelling the charter.
LAYDAYS
The ship-loading window allotted to a parcel of oil. A supplier names a period of time when his customer must lift the oil he has purchased. Cargoes get several days, barges perhaps a single day, consistent with the time required to load the quantity involved. The window takes account of the flexibility needed in commercial shipping. But it also considers shore tank capabilities and the need to use terminals and berths efficiently. Laydays, also called stem dates, can become the identity tag of a cargo. A refinery, for instance, which continuously produces and ships a grade of motor gasoline cannot make many practical distinctions between one lot and another. Hence, the trade talks about some oil company's July 14-16 unleaded regular or December7-9 DERD -2494.
LAYTIME
A specific number of hours, named in the pertinent charter party, a tanker must prepare to spend on berth at the ship-owners expense. Details vary from one fixture to another. Usually, though, owner and charterer agree on a total laytime for a voyage which must accommodate loading and discharge. The charterer pays for any hours over that number as demurrage.
LEAD
Tetra-ethyl (TEL) or tetra-methyl (TML) lead, primarily. These lead alkyls improve the octane rating of certain motor gasoline blendstocks quite inexpensively. Concern about the health effects of lead and other airborne pollutants generated restrictions on use of these octane boosters in many parts of the world over the past few years.
LEAD RESPONSE
The susceptibility of a motor gasoline blending component to octane improvement by addition of lead alkyl anti- knock compounds.
LIFT
To take purchased product by loading it aboard a transportation vessel at the point of production or storage.
LIFTER
A product purchaser who takes (lifts) crude, fuel, or feedstock physically from a producer's or reseller's facility. Oil frequently has a buyer and a lifter. The buyer, sometimes a contract holder, sells his stem to someone else who lifts it from the source.
LIFTING SUBJECTS
Confirmation of a deal by removal of any exceptions--any subjects--left open at the time of its conclusion.
LIGHT ENDS
Hydrocarbons lighter than naphtha derived from crude oil and natural gas processing. The industry also describes this collection of volatile materials as "C 4 and lighter." Butane, propane, ethane and methane, the predominant hydrocarbons in this cut, would evaporate once separated from the rest of the oil barrel unless confined in special storage vessels or re-dissolved in heavier fractions. All the substances in this fraction boil below 90 F.
LIGHT NAPHTHA
A naphtha cut with a boiling range which commonly extends from pentane through 175 F or perhaps a bit higher. The exact end point varies with the needs and objectives refiner. See NAPHTHA.
LIGHT PRODUCTS
Refinery products in the middle distillate and naphtha boiling ranges.
LIGHTERING
Ship-to-ship transfer of cargo in deepwater to complete loading of a vessel leaving a shallow load port (or berth) or to partially unload one which draws too much water to reach a shallow point.
LOA
Length-over-all. Distance between the fore-most and aft-most points of a ship.
LOADED SPECS
The quality of a cargo of oil as tested at loading aboard a vessel. Information frequently offered as actual specifications.
LOCATION SWAP
A deal in which companies trade oil in one place for some somewhere else.
LONG RESIDUE
See ATMOSPHERIC RESIDUE.
LOW POUR
A description of distillate or residual fuel oils, which flow at relatively low temperatures. Sometimes, the industry uses this term, and its opposite, informally. Frequently, though, it designates oil meeting specific standards of a particular market.
LOW-SPEED DIESEL
Very powerful, heavy-duty diesel engines such as those used to drive ocean-going ships and large electricity generators. These engines burn residual oil.
LPG
Liquefied petroleum gas. Propane and butane captured as by-products of natural gas and crude oil processing.
LPG CARRIERS
Tankers fitted to transport such volatile products as propane, butane, ammonia, and vinyl chloride monomer. These cargoes require high-pressure or refrigerated storage to keep them in liquid form. In these times of slack employment in their specialty, some of these tankers haul low-density clean products such as natural gasoline and naphtha. A few LPG carriers equipped with unusually powerful cooling systems can transport ethylene.
LR-1
AFRA's large-range 1 tankers. These ships' deadweight tonnages fall between 45,000 and 79,999.
LR-2
AFRA's large-range 2 tankers. These vessels have deadweight tonnages between 80,000 and 159,999.
LUMPSUM
A price for oil transportation quoted as a total for the cargo. This approach differs from the popular practice of charging a rate per ton carried. Lumpsums also differ from the rate method by including canal tolls and other items usually treated as surcharges.
MARKET RELATED
See FLOATING PRICE.
MEDIUM-SPEED DIESEL
Moderately large diesel engines such as those which propel large boats and heavy-duty locomotives. These engines burn a heavy gasoil which sometimes takes their name.
MERCAPTANS
Mercaptan sulfur. Excessive concentrations of these malodorous organic sulfur molecules make motor gasoline unmerchantable. Blenders, therefore, want to know the mercaptan content of components they could consider buying. The kerosene trade pays careful attention to this form of sulfur too. Jet fuel, and sometimes burning kerosene, have mercaptans limits.
METALS CONTENT
A specification of concern to buyers of fuel oil and vacuum gasoil. Heavy metals, such as nickel, vanadium, and copper, poison cat-cracking catalysts. Most refiners specify a maximum metals limit for the catfeed and vacuum unit feedstock they would consider purchasing. Traces of metal, particularly lead, also worry reformer feedstock buyers.
MIDDLE DISTILLATES
Products heavier than motor gasoline/naphtha and lighter than residual fuel oil. This range includes heating oil, diesel, kerosene, and jet kero.
MID-POINT
The temperature where 50 percent (weight or volume basis, as specified) of a natural material or refined product has boiled. Sometimes called 50 percent point.
MOGAS
An abbreviation of motor gasoline.
MON (Motor Octane Number)
A rating of the anti-knock properties of a finished motor gasoline or blendstock. The test determines MON simulates demanding engine operating conditions such as substantial loads and high speeds. The MON method yields lower numbers than the RON (research octane number) test which reflects milder conditions.
MONOMER
One molecular unit which links with others of its own or a similar kind to form a Styrene monomers, for instance, connect to form the familiar plastic, polystyrene.
MOTOR ALKYLATE
Full name of a gasoline blendstock often simply called alkylate.
MOTOR GASOLINE
Petroleum-derived fuel blend intended to power spark-ignited internal combustion automobile engines. This propellant's boiling range can span C4 through 430 F. In practice, it usually has a somewhat lower end point. Mogas must meet various specifications depending on the where and when it sells. Governments, climates, seasons, and market organizations all impose quality restrictions on the product. Most grades intended for modern motors resemble the fuel described by ASTM D 439. Mogas differs in some respects from aviation gasoline (avgas) a mixture blended for internal combustion airplane engines
MR
AFRA's 25,000 to 44,999 DWT class of tankers.
NAPHTHA
A product of crude oil or condensate refining which boils in roughly the same range as motor gasoline. In general, the naphtha distillation range spans from a bit less than 100 F, the boiling point of pentanes, through 300-400 F, depending on the intentions and needs of the refiner. The trade refers to this entire C5 to 300-400 F cut as whole or full-range naphtha. Refiners often produce two separate naphtha cuts when they distill crude, a light and a heavy fraction. They have rule-of-thumb boiling ranges of C5 through 175-200 F and 175-200 through 300-400 F. Refiners obtain naphtha's from conversion units in addition to the straight-run streams from crude distillation. Catalytic crackers and cokers, in particular, produce cracked streams which boil in the naphtha range. See light naphtha, heavy naphtha, hydrocrackate, naphthenic naphtha, paraffinic naphtha, and whole naphtha.
NAPHTHENES
Hydrocarbon molecules with a carbon ring structure similar to aromatics. Naphthenes have saturated bonds rather than the unsaturated ones which characterize aromatics. Reformers make aromatics, the high-octane components they intend to produce, most easily by desaturation naphthenes rings. The "N" in PONA and N+A stands for naphthenes.
NAPHTHENIC
High in naphthenes-ring content. Lower than ordinary paraffins concentration. In some casual applications this adjective tacitly embraces aromatics as well as naphthenes, as in naphthenic naphtha.
NAPHTHENIC NAPHTHA
A naphtha stream with a comparatively high concentration of naphthenes and aromatics. The terms reforming naphtha and N+A naphtha also identify this class of hydrocarbons. In general, American and Japanese companies regard a stream as naphthenic or highly naphthenic if it has a naphthenes plus aromatics concentration of 40 percent or more. Europeans use a lower standard-in the mid-30's. Naphthenic naphtha's normally find use as reformer feedstock.
NATURAL GASOLINE
The pentanes-and-heavier fraction produced by processing wet gas in an LNG or LPG plant. Such materials can substitute for paraffinic naphtha's in a number of uses including, depending on the qualities of individual streams, gasoline blending and steam cracker feedstock.
NEW WORLDSCALE
The Worldscale tanker rate schedule based on revised assumptions which take effect on January 1, 1989.
NGL
Natural gas liquids. Natural gas processing yields a variety of liquids which can range from ethane to field condensate. The specific liquids included under this designation differ from company to company and from one part of the industry to another.
NO OIL
ASTM's grade of oil for commercial applications which benefit from heavy fuel but lack heated storage tanks. Refiners sell heavy distillate or a blend of distillate and residue as No. 4 oil. Medium-speed diesels can burn a version of this product designated No. 4-D.
NO. 2 OIL
ASTM's designation for distillate fuel oil intended for burning in household and light commercial furnaces. A companion grade, No. 2-D, fuels high-speed diesel engines. The USA, which relies more than other countries on ASTM specs to define oil products, generally distributes just one kind of No. 2, a dual grade suited for diesels and burners. See gasoil.
NO. 5 OIL
The ASTM grade of residue suitable for unheated storage in mild climates.
No. 6 OIL
Heavy fuel oil too viscous for burning without preheating. See residue.
NO-HEART CRUDE
Crude fluid enough at ambient temperature to permit transportation in vessels which cannot heat it.
NOR
Notice of readiness. When a tanker reaches port to lift or deliver cargo, it gives its NOR. This signal announces its arrival and its desire to berth. Frequently, market-related crude and products deals price cargoes on or around their NOR dates, the days duly fixed and scheduled vessels arrive to load or discharge them.
NORTHERN GRADE
Motor gasoline that meets Colonial pipeline specifications for product delivered to points north of Greensboro, North Carolina. Both distillation range and volatility differentiate Northern grade gasoline from Southern grade. Finished gasoline must be more volatile in certain states during winter months to assure proper ignition. In warm weather less volatile finished gasoline helps prevent autos from suffering vapor lock. During the months of March, May, September and November the quality specifications are the same for both Northern and Southern grades.
OBO
Oil-Bulk-Ore carriers. These versatile ships can transport cargoes as various as crude oil, grain, coal, and metal ore. They feature simply-shaped holds without exposed hull framework to permit easy cleaning between cargoes of different kinds. Certain OBO's, called PROBO's specialize in carrying oil products (vegetable and mineral) and soft bulk cargo. Efficient participation in the petroleum products trade requires these ships to have epoxy-coated holds. This provision aids thorough removal of a discharged cargo's traces before loading another. Unfortunately, epoxy cannot endure a great deal of physical abuse. So PROBO's cannot carry ore, coal, and other hard bulk cargoes.
OCTANE
A measure of a motor gasoline's or blendstock's resistance to preignition (knocking). The industry commonly uses two different indexes of this quality RON (research octane number), and MON (motor octane number). The USA employs an average of the two: (R+M)/2.
OLEFIN
A straight or branched-chain hydrocarbon with at least one unsaturated carbon-carbon bond. The petrochemical industry's highest volume product, ethylene, belongs to this family of molecules. Cracking processes produce such molecules in considerable quantity. The "O" in PONA stands for olefins.
OPEN SPEC
A description of the substance sold in certain petroleum products transactions. Buyer and seller agree to price, delivery range and other particulars, but only to general specifications for the material. The seller covers the deal with any availability falling within the limits accepted by the trade.
OPERATIONAL TOLERANCE
Flexibility in the quantity of a stem, usually expressed as a small percentage of the stern's nominal size. This provision makes it easier to find suitable ships to lift crude and products.
OSP
Official selling price. See posted price.
OUTTURN
As measured at vessel discharge. The industry uses this term as a description of the oil unloaded at a buyer's terminal. It indicates that measurements taken at the delivery of a parcel will determine the quality or quantity, or both, of a parcel changing hands. Common phrases incorporating this term include "outturn barrels", "outturn quantity", "outturn quality", and "outturn Q and Q".
OVERHEAD STREAM
The fraction which leaves through the top of a distillation column as a gas.
OXIDATION STABILITY
Resistance to change when exposed to air. Motor gasoline should have this property. Otherwise it will form gum when stored.
OXYGENATE
Oxygen-containing molecules such as alcohols or ethers used either for volume or octane, or both, in motor gasoline blending. Common examples of such compounds include ethanol, tertiary-butyl alcohol (TBA), and methyl-tertiary-butyl ether (MTBE).
PANAMAX TANKERS
Oil carriers which meet the 32.2 meter beam and 259 meter LOA limitations of the Panama Canal. Modern ship design translates those dimensions into a vessel with a maximum deadweight tonnage around 70,000.
PAPER BARRELS
Also known as dry barrels or electric barrels, these units trade in the futures or other non-physical markets. These terms designate the opposite of the wet barrels traded in physical deals. Since short sales in the wet market involve product the seller does not own at the time of making the deal, dry barrel terminology may apply.
PARAFFINIC
A high concentrate of paraffins, usually in distinction from naphthenic or olefinic mixtures.
PARAFFINS
Straight- or branched-chain hydrocarbons containing no unsaturated carbon-carbon bonds. A high paraffins content gives a naphtha a low octane rating, a diesel oil a high octane number, and a vacuum gasoil or straight run fuel oil a good susceptibility to catalytic cracking. The trade often uses the term waxy to signify a high paraffins content in a heavy distillate or resid. The "P" in PONA stands for paraffins.
PARCEL TANKER
A ship fitted to segregate a large number of products. Some of these vessels, called chemical carriers, can handle more than a dozen materials simultaneously. Most of these ships have tanks made of stainless steel or lined with inert, easily cleaned coatings. This equipment permits carriage of high-purity or corrosive materials, or simply the use of tanks for a succession of assorted materials without contamination problems. The trade likes to call these flexible vessels "drugstore ships".
PARAFFINIC NAPHTHA
A naphtha composed primarily of paraffinic molecules. In general, the feedstock trade considers 65 percent paraffins content the minimum for a paraffinic naphtha. Paraffins have a low octane rating. They crack readily, however. This combination of properties gears paraffinic naphtha's for ethylene feedstock more than for high-octane motor gasoline blending.
PERIOD BUSINESS
Deals which involve transfer of merchandise or delivery of service (transportation, for instance) from seller to buyer over a stretch of time. See term deal and time charter.
PGO
This acronym designates two different intermediates. See process gasoil and pyrolysis gasoil.
PIPESTILL
A traditional industry name for crude distillation units. The term generally applies to atmospheric stills. "Vacuum pipestill," used infrequently, refers to vacuum distillation units.
POISE
The unit of absolute viscosity. The trade often uses centipoises. One poise equals 100 centipoises.
POLYMER
A strand of monomers. By definition, it takes five or more of these combining units to make a polymer. Shorter chains have individual names (dimer, trimer, and tetramer). Most familiar synthetic polymers, plastics like polystyrene, polypropylene, and polyvinyl chloride for instance, contain a huge number of monomers--practically too many to count.
PONA
A breakdown of the kind of molecules which compose a hydrocarbon mixture. The trade uses PONA most frequently to describe naphtha's. See paraffins, olefins, naphthenes, and aromatics. All hydrocarbons fall into one of these four categories. The feedstock trade characterizes naphtha's by what percentage of each kind of molecule they contain. A PONA test determines the composition of a particular cargo or stream.
POSTED PRICE
The published or list price of crude and petroleum products, sometimes shortened to "posting." Many companies use this term as a name for the price applied to their contract business. In some cases, it means the commodity's base price--the starting figure subject to adjustments such as competitive allowances, volume discounts, equity compensation, and so forth. Most of the time sellers post prices. But in some cases, such as the US domestic crude market, buyers post what they will pay.
POUR POINT
The temperature where a hydrocarbon mixture becomes too thick to flow. The industry uses this property to assure that gasoil will fuel furnaces and diesel engines properly during cold weather. In particularly harsh climates, pour point indicates how warm to keep distillate by artificial means. The trade also quotes pour points for residue and crude. In these cases, the specification indicated whether the oil needs heating for proper handling and storage.
PPB
Parts per billion. A thousand times less than a ppm. An expression for tiny concentrations of one ingredient (usually a contaminant) in a mixture. One milligram per kilogram equals one weight ppm.
PPM
Parts per million. A convenient expression for very small concentrations of one ingredient (usually a contaminant) in a mixture. One milligram per kilogram equals one weight ppm. So does 1 gram in a metric ton. The industry does not regularly use volume ppm, but could if it had a reason.
PRECURSOR
A stream or molecule transformed into a specific product by a reaction or other processing. Refiners, for instance, regard naphthenes as aromatics precursors because they readily become aromatics in reformers.
PRESSURING AGENT
Butanes used to control the vapor pressure of finished gasoline. Usually butane's price, relative to other components' and finished gasolines. gives refiners incentive to put as much butane as possible in their blends. During the winter months, when RVP specifications rise, motor gasoline can contain more butane.
PROBO
Product-Bulk-Oil carriers. See OBO.
PROCESS GASOIL
A synonym for vacuum gasoil. Processing arrangement: See TOLL PROCESSING Also called processing deals.
PRODUCERS
Companies, often state organizations, which own oil wells and the crude which flows from them. This category includes a large number of private enterprises. Integrated oil companies and specialists called independent producers develop much of the world's crude supply. But, as a matter of custom, the industry tends to think not of them but of oil exporting nations when speaking of producers. Other names, such as equity holders, leaseholders, or even equity producers, distinguish these private, commercial organizations. They need a separate category because they must buy the oil they develop, through lease fees, royalties, cash, production sharing, or other arrangements, from whoever has sovereign right to it.
PROPYLENE
Three-carbon olefin produced in refineries by catalytic crackers and in petrochemical plants by steam crackers. Refiners process part of their supply into motor gasoline blendstock, particularly alkylate. Some refinery material and that from steam crackers becomes plastic, glue, and other synthetic products.
PSI
Pounds per square inch (lbs/in2). A common unit of pressure particularly vapor pressure. Some folks express pressure specifications in kPa or bars. 1.0 lb/in2 = 0.068947 bar = 6.8947 kPa
PYGAS
An abbreviation of pyrolysis gasoline.
PYROLYSIS
Application of heat to change molecular structure. The oil industry ordinarily reserves this term for processes which break hydrocarbons without the assistance of a catalyst, such as steam cracking and cooking.
PYROLYSIS GASOIL
The distillate fuel oil produced by a heavy liquids steam cracker. This material usually finds use as a distillate blendstock.
PYROLYSIS GASOLINE
The aromatics-rich naphtha-range stream produced in sizeable quantities by an ethylene plant when it cracks butane, naphtha, or gasoil. Pygas resembles reformate. It can serve as a high-octane blendstock for motor gasoline or as a feedstock for an aromatics extraction unit.
R+M/2
A misleading, but popular, expression of (R+M)/2. See antiknock index.
RACK BLENDING
The practice of adding one or more components to a gasoline blend at an inland distribution terminal. Frequently, due to logistics, this type of blending occurs at the end of the distribution line. For instance, a supplier will add ethanol to finished gasoline while loading delivery trucks for shipment to retail outlets. This method of blending prevents ethanol, which has an affinity for water, from separating from the gasoline blend (phase separation) during transportation through a pipeline system.
RACK PRICE
The truckload price charged by a supplier to customers which buy motor gasoline on an FOB terminal basis.
RAFFINATE
what remains of a reformate or pyrolysis gasoline stream after aromatics extraction. These paraffinic, naphtha-range mixtures usually have too low an octane rating for use in motor gasoline, but good properties for steam cracking. Butylene streams produced by ethylene plants also go by the name raffinate, or raff.
RAMSBOTTOM CARBON
A measurement of hydrocarbon mixtures' tendency to leave carbon deposits (coke) when burned as fuel or subjected to intense heat in a processing unit such as a catalytic cracker. See CONRADSON CARBON.
RATABLY
On a ratable basis. The industry uses this expression for paced delivery of product. Crude, for instance, can move from buyer to seller at some speed like a thousand barrels per day. The idea applies most naturally to pipeline-carried commodities.
REALIZATION
Evaluation based on theoretical (often negotiated) estimates of how much money a refiner or petrochemicals producer can make by processing a feedstock. Many netback deals price oil according to a formula which considers the quantity and spot value of products made from it and the cost of processing. These transactions have a realization basis.
REDUCED CRUDE
Atmospheric fuel oil. See ATMOSPHERIC RESIDUE.
REDWOOD VISCOSITY
A method of measuring and reporting viscosity which lost popularity in recent years. Tables available from various sources convert Redwood figures to the more widely used Kinematic and Saybolt scales.
REFINERY INTERMEDIATE
See INTERMEDIATE.
REFORMATE
The product of a catalytic reformer. An aromatics-rich high-octane motor or aviation gasoline blendstock. Many refineries route a part of the reformate they produce through aromatics extraction units to recover the benzene, toluene, and xylenes it contains.
REFORMER
A catalytic processing unit which produces a highly aromatic stream (reformate) used primarily as high-octane blendstock.
REFORMING NAPHTHA
See NAPHTHENIC NAPHTHA.
RELET
A ship offered for hire by its time-charterer. Large international oil companies, because they take far more tankers on a period basis than anyone else, engage in reletting most frequently.
RESID
Abbreviation of residue.
RESIDUE
The bottoms taken from distillation units. Both atmospheric and vacuum stills yield a residue. The industry sometimes uses "bottoms" to designate this unboiled material. Atmospheric residue can undergo further distillation in a vacuum unit. Heavy fuel oil blending absorbs much of the vacuum residue produced; although some serves as feedstock for coking, asphalt manufacture, and other upgrading processes.
RON (Research Octane Number)
A rating of the anti-knock properties of a finished motor gasoline or blendstock. The test to determine RON stimulates mild engine operating conditions such as motoring at moderate speeds. The RON method yields higher numbers than the MON (motor octane number) test which reflects heavy loads and high speeds.
RVP
Reid vapor pressure. A measure of the volatility of hydrocarbons. The Reid test can measure volatility at any practical temperature. A testing temperature must accompany any RVP report to make it most informative. Ordinarily, the feedstock and petroleum products trade uses RVP numbers measured at 100F.
S.G
An abbreviation of specific gravity.
SATURATES
Hydrocarbons with no multiple bonds. Paraffins and naphthenes.
SCREEN
Oil trading jargon for the electronic network quotes of futures market prices. Other nicknames include "the TV" and "the print." The industry discusses physical market activity and does business at levels which sound like "screen plus 25" and "85 points under the print."
SECONDARY PROCESSING
Cracking, alkylation, and other molecule alteration. Refining beyond the capabilities of a topping plant or hydroskimmer.
SEGREGATED BALLAST TANKS (SBT)
Chambers on a tanker used exclusively to hold ballast water. Ships so equipped need not fill cargo tanks with sea water on unladen voyages. Such vessels need not worry that they will pump oil traces overboard when they deballast.
SEGREGATION
Keeping two or more parcels of crude or product isolated from one another aboard a tanker. Ability to prevent contact between part-cargoes may depend upon not only separate tanks but also separate pumps and piping to handle each grade. The trade would say that a ship which can keep apart three kinds of oil has "three segregations."
SEVERITY
The degree of application of pressure, temperature, duration, or other critical processing conditions. The more exposure of a feedstock to factors which promote an intended reaction, the more severe the processing. Higher temperatures, greater pressures, longer residence times, and so forth, constitute greater severity in various processes.
SFS
See SSF.
SHIP'S FIGURES
A quantity of cargo loaded or discharged by a tanker as tabulated using the ship's calibration tables. The trade regularly compares these numbers with shore tank figures. Observers take samples of cargo as it comes aboard. But they do not ordinarily have them tested for quality unless a dispute arises. Most outturn quality reports, on the other hand, come from samples taken from the vessel's tanks at the discharge port.
SHORE TANK FIGURES
Quality data on a shipment derived from storage tank samples taken prior to loading or quantity determination based on storage depletion in the course of loading. Shore tank gauging could also give useful information on the quantity of oil discharged into a receiver's terminal. The industry ordinarily tests discharge (often called outturn) quality of unloaded oil before it moves ashore. These data come from unloading line or ship's composite samples. Suppliers and receivers often use shore figures to verify or dispute ship's figures.
SIMPLE REFINERY
A facility which has no cracking or other secondary processing hardware. "Simple yields," therefore, mean the product slate such an unsophisticated plant can make from crude. See topping yields.
SMOKE POINT
An indication of how cleanly kerosene burns. The test reports how high a flame can extend above a wick-fed lamp without making soot.
SOUR
High in sulfur content. Sour vacuum gasoil's, for example, contain more than about 0.5 sulfur, the common limit for sweet vacuum gasoil's. Application of this term to natural gasolines tends to focus on mercaptan sulfur concentration. Sour natural gasolines test Doctor positive.
SOUR CRUDE
Petroleum with high sulfur content. In this case, high commonly means more than 1.0 weight percent.
SOUTHERN GRADE
See Northern grade. Motor gasoline that meets Colonial pipeline specifications for product delivered to points south of Greensboro, North Carolina
SPECIFIC GRAVITY
An expression of materials' density in terms of their relationship to a reference substance. Water at 4 C serves as the reference for hydrocarbons, both liquid and solid. Water has specific gravity of 1.0, as 1 cc of its weighs 1 gram. The specific gravity of liquid hydrocarbons indicates the ratio of their density in cc/gram to water's. For example, motor gasoline typically has a density around 8.5 barrel per metric ton, or 0.740cc per gram. That makes its specific gravity (0.740 cc/gram mogas)/(1.0 cc/gram water) = 0.740. Full expression of specific gravity requires specification of a temperature for both the described and the reference substances. Therefore, a complete citation of a motor gasoline sample's specific gravity might read 0.740 @ 60 F/39.2 F. The formula found under API gravity can convert specific gravity to API degrees.
SPIKE
Injection of one stream into another for later recovery. Transportation of some condensates, for instance, takes place by spiking them into crude oil cargoes.
SPOT CHARTER
Arrangement for a ship to carry a certain cargo on a particular route. Such deals, sometimes called voyage charters, usually cover a single trip. Commitments for two or more consecutive voyages do happen, though, occasionally. In a spot charter, the ship owner pays fuel and port charges. This assignment of costs distinguishes spot business from time-charters. When a charterer takes a vessel for a period rather than a voyage, he pays bunkers and port charges.
SPOT DEAL
An isolated sale. In transactions of this kind, a specific quantity of oil, usually a convenient unit like a cargo, a barge load, or a pipeline batch, changes from seller's hands to buyer's. The notion once assumed promptness. That element has vanished now that companies trade spot oil many months forward. In today's vernacular, "spot" chiefly distinguishes self -contained transactions from period business, sometimes called deals or contract deals.
SSF
Saybolt seconds, Furol. The unit of Saybolt Furol viscosity, a method of determining liquids resistance to flow. An alternate acronym, SFS, for Saybolt Furol seconds, remains in use.
SSU
Saybolt seconds, Universal. The units of an empirical flow resistance measurement (Saybolt Universal viscosity). The acronym sometimes appears as SUS, Saybolt Universal seconds.
STABILITY
Crude and products which will not change spontaneously or readily have this attribute. Jet fuels, for instance, need thermal stability. They must resist decomposition when heated.
STABILIZED CRUDE
Crude and condensates come from the ground mixed with gas and light gas liquids. Removal of these volatile materials leaves a stabilized stream--one with a vapor pressure ordinary storage and transportation vessels can safely handle.
STABLE
The notion of constancy and steadiness has several applications in the oil industry. Frequently it describes crude freed of volatile light ends--stabilized crude. Other times, it refers to blends of compatible components, mixtures which will not spontaneously separate. Stable cracked fuel oil, therefore, means a combination of ingredients which will not divide into two parts, each insoluble in the other.
STANDARD EXPORT QUALITY
A common description of crude oils sold on the world market. The normal run of a crude grade as available at a loading point.
STEAM CRACKER
A petrochemical plant unit which produces olefins, particularly ethylene, and in some cases aromatics, by pyrolysis. The trade often calls these plants ethylene crackers, after their primary product. Some units, called light liquids crackers, crack ethane or LPG. Heavy liquids crackers can run on naphtha or gasoil feedstocks.
STEM
A parcel of crude or product made available by a supplier. Sometimes a lot provided to a term lifter. Sometimes a spot availability.
SWEET
Low in sulfur content. See SOUR.
TERM DEAL
An agreement for a customer, or lifter, to buy a supplier's oil over a period of time. Such arrangements obligate seller to provide and purchaser to take, and pay for, a named quantity of specified merchandise at a defined price over a number of months or years, usually according to some sort of schedule. The opposite of a spot deal.
THERMAL CRACKER
Originally, the name of the refining industry's first molecule breaker. These units used heat and pressure to turn heavy fuel oil into gasoline and distillate. Today, the term applies to a category of bottoms crackers, including visbreakers and cokers, which rely on heat to destroy residue.
THERMAL STABILITY
Reluctance to change, especially to deteriorate, when heated. A property particularly associated with aviation turbine fuels.
THIRD-PARTY PROCESSING
See TOLL PROCESSING.
TIME SWAP
An exchange which involves today's barrels for tomorrow's or next week's for next month's.
TIME-CHARTER
Lease of a ship to a charterer for a period of time rather than for the performance of a specific voyage. An elemental version of this arrangement, called a bare boat charter, works like renting an unfurnished apartment. The charterer must provide his own master and crew. In other cases the owner provides personnel and various services.
TOLL PROCESSING
Refining or petrochemicals production done on a fee basis. A plant owner puts another party's feedstock through his equipment and charges for the service. A portion of the product retained by the processor may constitute payment. This form of compensation occurs frequently in refining because the feedstock supplier often wants only one part of the output slate.
TOLUENE
Gasoline blenders and petrochemicals makers continually compete for possession of this aromatic. Its high octane and low vapor pressure make it an excellent blendstock. The chance to turn it into benzene appeals to the chemical industry. Refineries and steam crackers both produce it in large quantities.
TOPPING PLANT
A simple refinery, one which lacks cracking and other upgrading equipment. The name comes from what such basic installations can do. They boil the straight-run light products, the top, off crude oil. The most rudimentary topping plants have no complex hardware at all. A slightly more sophisticated type adds a vacuum still to separate VGO from the crude unit's residue, but the facility would not have a cracker to convert the VGO.
TOPPING YIELDS
The product slate obtained by processing a grade of crude in a simple refinery. In everyday industry usage, the term usually means the yield from atmospheric distillation followed by naphtha reforming and finished product blending.
TRIM
The angle at which a ship floats when viewed from the side. It can rest stern high, bow high, or on an even keel. Masters must load their ships with safe trim in mind.
TYPICALS
Specifications considered representative of a crude or product stream. Parcels, particularly of feedstocks, often trade on typicals even though such data carries no absolute commitments or legal obligations.
ULCC
Ultra large crude carrier. The largest tankers. AFRA defines them as 320,000 DWT and larger. Most folks use the term a little less precisely. They might use it for ships as small as 300,000 or even 280,000 tons.
UNIT
A major piece of refining equipment. Any collection of machinery worthy of this title includes the complete set of hardware necessary to perform a process step. A crude distillation unit, for instance, incorporates a furnace, a fractionation tower, and all the pipes, pumps, and heat exchangers required to separate crude into cuts.
UNSATURATED GASES
Light ends produced by refinery cracking units, particularly catalytic crackers and cokers. "Unsaturated" indicates the high olefins content of these gases. They ordinarily go to their own separation unit, plainly labeled an unsaturate gas plant, to avoid contaminating the paraffinic, straight-run LPG which uses the saturate gas plant.
UNSATURATES
Hydrocarbons containing double or triple bonds. Olefins and aromatics which feature carbon-carbon double bonds have particular importance in the oil industry.
UPSTREAM
A relative term which locates one point closer to origins than another. Crude distillation lies upstream of conversion processing, for example. The opposite of downstream.
V/L RATIO
Vapor/Liquid ratio. A measure of volatility which observes volume of vapor a given volume of liquid forms at various temperatures. Gasoline blenders, who make more use of this property than anyone else, report it as the temperature where a sample reaches, or should reach, a desirable volume/liquid ratio.
VACUUM BOTTOMS
The 1050 or 1100 F+ pitch which remains after a vacuum flasher removes vacuum gasoil from atmospheric bottoms. This thick residue has no direct use unless it meets asphalt specifications. Many refineries need to blend it into heavy fuel oil. The more fortunate can destroy it in a cooler or upgrade it in a visbreaker.
VACUUM DISTILLATION
A technique for recovering heavy distillates from residue. The process lowers pressure under the level of the atmosphere, thereby reducing the temperature where hydrocarbons boil. This approach gives refiners access to molecules which would crack before they evaporated in a crude distiller.
VACUUM DISTILLATION
A technique for recovering heavy distillates from residue. The process lowers pressure under the level of the atmosphere, thereby reducing the temperature where hydrocarbons boil. This approach gives refiners access to molecules which would crack before they evaporated in a crude distiller.
VACUUM GASOIL
A product of vacuum distillation with a typical boiling range of 550-700 F to 1050-1150 F. Cat crackers process vacuum gasoil (catfeed). So do a few heavy liquids steam crackers.
VACUUM UNIT
A distillation column run at a pressure below the level of the atmosphere in order to separate atmospheric residue into vacuum gasoil and vacuum bottoms. See VACUUM FLASHER.
VAPOR PRESSURE
The pressure generated by gases boiled off a liquid in a closed space. Standardized tests of this property, Reis method (RVP) most popular among them, report the observed pressure of liquid and gas in equilibrium at a particular temperature.
VGO
An acronym for vacuum gasoil. Some organizations use the term process gasoil, and the acronym PGO, for this feedstock.
VIRGIN
A description applied to streams which have not undergone a critical processing step. Most frequently, the term designates straight-run distillation cuts free of conversion refining products, such as virgin naphtha.
VISBREAKER
A mild thermal cracker that treats crude unit or vacuum distiller bottoms to make them more fluid. Such units break some of the molecules, which flow poorly in these mixtures. The residue gives up some small molecules cracked off long hydrocarbon chains. The refinery collects these pieces, depending on their boiling range, as cracked gas, cracked naphtha, gasoil, and cat cracker charge. This breaking process contributes most to refining economics by reducing the amount of cutter required to blend still bottoms into saleable fuel oil.
VISBROKEN NAPHTHA
The cracked naphtha produced by a visbreaker.
VISCOSITY
A measure of liquids' resistance to flow. The oil industry uses several measurements, including Saybolt, Redwood, Engler, and Kinematic, to report how fast crude or product moves, or should move, at specified temperatures. Since heavier hydrocarbon mixtures flow easier when heated, any meaningful viscosity specification must indicate a test temperature.
VLCC
Very large crude carrier. A tanker between 160,000 and 319,999 deadweight tons, according to AFRA. In common usage, the industry tends to apply the term loosely. A round 150,000 to 300,000 DWT fits casual expectations.
VOLATILITY
The tendency of crude or products to yield vapor. Volatile materials give off gas at everyday temperatures. Hydrocarbon mixtures, such as motor gasoline, may qualify as volatile because they contain components which evaporate readily. The industry usually measures vapor pressure to determine crude and products' volatility.
WATER REACTION
A hydrocarbon mixture's tendency to hold water and other impurities in suspension. Aviation turbine fuel has specifications, including a water separation index, to avoid putting kerosene with this problem aboard aero planes.
WATER SEPARATION
See WATER REACTION.
WAX CONTENT
A synonym for paraffins content most frequently applied to catalytic cracker feedstocks. A high wax, or paraffins, content makes a residue of gasoil more susceptible to cracking.
WAXY
Paraffinic.
WET BARREL
Physical product. The trade distinguishes material promptly available, wet barrels, from future or paper availabilities.
WHOLE NAPHTHA
A distillation cut which spans the entire boiling range commonly designated as naphtha. This full-range product contains the fractions separable into light naphtha and heavy naphtha. Its initial boiling point can commonly fall between 90 and 100 F and its final boiling point extend as high as 400 F.
WORLDSCALE
Worldwide Tanker Nominal Freight Scale. Worldscale Association, a shipping industry group, publishes a lengthy schedule of rates for popular tanker voyages. The printed figures, called World scale 100's, reflect application of tanker operating cost assumption to the ports and distance/steaming time on route. These "flat rates" appear in US dollars per ton of cargo. Ship-owners and spot charterers usually negotiate the hire price of a tanker as percentage of Worldscale 100 for the voyage involved. They might fix at Worldscale 40 (WS 100 x2.00), or any other number dictated by size and kind of ship, market conditions, and negotiating skill.
WSIM
Water Separation Index Modified. See WATER REACTION.
XYLENES
Xylene comes in three different isomers: ortho-xylene, meta-xylene, and para-xylene. The first and last of this threesome have important chemical uses. All of them, separately or together, make superior motor gasoline blendstock. Refinery reformate and steam cracker pyrolysis gasoline, when put through an aromatics recovery unit, yield all three, plus another eight carbon compound called ethylbenzene, in the form of mixed xylenes.
YIELD
The quantity and/or quality of derivatives a process can make, or actually makes, from a feedstock or raw material. The industry speaks of gasoline yields from CRUDE; ethylene yields from naphtha, VGO yields from long residue, light products yields from cat cracking, and so forth.
YIELD SLATE
The breakdown of various derivatives from processing a feedstock or raw material. Typical yield slates could list the quantities of various fuels made from a grade of crude in a certain type of refinery, or basic petrochemicals from steam cracking a particular ethylene feedstock