The Comprehensive Flowmeters Resource


Abel tester:   A closed-cup flash tester for kerosene and other types of oil

Absolute pressure:  Total pressure equal to gauge pressure plus 14.7 lbs./sq. in at sea level

Acidity: The presence of acid-type constituents whose concentration is usually defined in terms of neutralization number. The constituents vary in nature and may or may not markedly influence the behavior of the oil

Air-Fuel Ratio: The ratio of air weight to fuel weight consumed in an internal combustion engine or furnace

Aliphatic: A class of saturated or unsaturated carbon compounds, in which the carbon atoms are joined in open chains.

Aniline Point: The aniline point of a petroleum product is the minimum equilibrium solution temperature with an equal volume of freshly distilled aniline.

API:  American Petroleum Institute

API Gravity:  Gravity (weight per unit volume) of oils as measured by the API scale.

Aromatics:   A Group of hydrocarbons of which benzene is the parent. They are called “aromatics” because many of their derivatives have a sweet or aromatic smell.

Ash: Inorganic residue remaining after ignition of combustible substances determined by definite prescribed methods

Asphaltenes:  Insoluble, semi-solid, or solid particles which are combustible and are highly aromatic.

ASTM: American Society for Testing Materials. Grade and quality specifications for petroleum products are determined by ASTM test methods

Atomization characteristics: The ability of an oil to be broken up into a fine spray by some mechanical means.

Barrel:  A unit of volume measurement used for petroleum and its products. 1 barrel = 42 U.S. gallons or 35 British gallons

Benzene:  An aromatic hydrocarbon which is a colorless, volatile, flammable liquid. Benzene is obtained chiefly from coal tar and is used as a solvent for resins and fats in dye manufacture

BHP:  Brake horsepower

Blenders: Devices for mixing two fuel oils to achieve a less viscous and more uniform fuels

Blending: Mixing of two compatible fuels having different properties in order to produce an intermediate fuel

BS & W:  Bottom sediment and water.

BS & W Monitor:  An instrument which detects entrained water content in petroleum products wherein the water changes the resistive capacitive as a function of the dielectric constant see

BTU:  British Thermal Unit. The amount of heat required to raise the temperature of 1 pound of water by 1 degree Fahrenheit

Bunker Fuel Oil: Heavy, residual fuel oil used in ships.

Calorie: The amount of heat required to raise the temperature of 1 gram of water by 1 degree centigrade, at or near maximum density.

Calorific Value:  Amount of heat produced by the complete combustion of a unit weight of fuel. Usually expressed in calories per gram or BTU’s per pound, the latter being numerically 1.8 times the former

Catalyst: A substance which promotes a chemical reaction, but does not itself enter into the reaction.

Catalytic Fines : Hard, abrasive crystalline particles of alumina, silica, and/or alumina silica that can be carried over from the fluidic catalytic cracking process of residual fuel stocks.

Cat Cracker: A large refinery vessel for processing reduced crudes or other feed-stocks in the presence of a catalyst, as opposed to the older method of thermal cracking, which employs heat and pressure only.

Centigrade: Temperature based on 0 for the temperature at which water freezes and 100 for the temperature at which water boils. Europeans do not accept this term for Celcius. See that term above. This term is accepted and used in North American chemical texbooks, so which term you use may depend on your location, but both are abbreviated with a degree symbol and capital C, so at least you now know what it means.

Centipoise:  0.01 poise or centistokes times specific gravity at the test temperature.

Centistoke:  0.01 stoke

Centrifuge:  A machine using centrifugal force produced by high-speed rotation for separating materials of different densities. Applied to Diesel engine fuels and lubricating oils to remove water and other extraneous materials

Cetane Index: An empirical measure of ignition quality. Defined as the percentage by volume of cetane in a mixture of cetane and methyl naphthalene which has the same ignition quality when used in an engine as a fuel under test

CCR:  Conradson carbon residue

CFR Diesel fuel testing unit: A standard engine employed in making cetane number tests of Diesel engine fuels

C/H Ratio:  Carbon/Hydrogen ratio

Clarifier:  A machine used for a liquid-sludge separation in which the particles with a higher specific gravity are separated form the lower specific gravity of the liquid. A clarifier bowl has one outlet for the light phase oil-the heavier phase particles are retained on the bowl wall

Cloud Point:  Temperature at which wax begins to crystallize from a distillate fuel

Corrosion:  Detrimental change in the size or characteristics of material under conditions of exposure or use. It usually results from chemical action either regularly and slowly as as in oxidation or rapidly, as in metal pickling

Cracked: Refers to a petroleum product produced by a secondary refining process such as thermal cracking or vis-breaking processes which yield very low quality residue.

Cutter stock:  Flux Stock. A petroleum stock which is used to reduce the viscosity of a heavier residual stock by dilution.

Demulsibility: The resistance of an oil to emulsification, or the ability of an oil to separate from any water with which it is mixed. The better the demulsibility rating, the more quickly the oil separates from water

Density: Density is the term meaning the mass of a unit of volume. Its numerical expression varies with the units selected

Desalter: The desalter mixes the hydrocarbon stream with a small amount of fresh water forming a water-in-oil emulsion. The resulting emulsion is subjected to an electric field wherein the water is coalesced as an under flow from the upper flow of a relatively water-free, continuous hydrocarbon phase. The desalted hydrocarbon stream is produced at relatively low cost and has a very small residual salt content.

Detonation:  A violent explosion involving high-velocity pressure waves; in a gasoline engine, the spontaneous combustion of part of the compresses charge after spark occurs.

Diesel index:  Product of the API gravity and the aniline point (in degrees Fahrenheit) of a Diesel fuel, divided by 100; an indication of the ignition quality of the fuel

Distillation:  The process of heating a liquid to its boiling point and condensing and collecting the vapors

Doctor test:  A qualitative method of detecting undesirable sulfur compounds in petroleum distillates, that is, of determining whether oil is “sour” or “sweet”.

Electrolytic process: A process that causes the decomposition of a chemical compound by the use of electricity

Emulsion: A liquid mixture of two or more liquid substances not normally dissolved in one another, one liquid held in suspension in the other. Water-in-oil emulsions have water as the internal phase and oil as the external, while oil-in-water have oil as the internal phase and water as the external

Fire Point:  The lowest temperature at which an oil vaporizes rapidly enough to burn for at least 5 seconds after ignition, under standard conditions

Flash point:  The lowest temperature at which a liquid will generate sufficient vapor to flash (ignite) when exposed to a source of ignition

Fraction: A separate identifiable part of crude oil; the product of a refining or

Fuel oil: The heavy distillates from the oil refining process; used as fuel for power stations, marine boilers.

Fungible: Interchangeable. Products which can be commingled for purposes of pipeline shipment.

Gasoil: A clean distillate fuel oil.

Heat of Combustion Gross:  Total heat evolved during complete combustion of unit weight of a substance, usually expresses in BTU per pound

Heat of Combustion Net:  Gross heat of combustion minus the latent heat of condensation of any water produced

Heavy crude: Crude oil with a high specific gravity and a low API gravity due to the presence of a high proportion of heavy hydrocarbon fractions and metallic content.

Homogenizer: A mechanical device which is used to create a stable, uniform dispersion of an insoluble phase (asphaltenes) within a liquid phase (fuel oil)

Hydrometer:  An instrument for determining the gravity of a liquid.

Initial Boiling Point.: In a standard laboratory distillation, the temperature on the distillation thermometer at the moment the first drop of distillate falls from the condenser

Innage:   Space occupied in a product container

IP: British Institute of Petroleum

Kinematic Viscosity: The ratio of the absolute viscosity of a liquid to its specific gravity at the temperature at which the viscosity is measured. Expressed in Stokes or Centistokes.

Latent heat:  Heat required to change the state of a unit weight of a substance from solid to liquid or from liquid to vapor without change of temperature

Layering: An occurrence in tanks when a high density fuel is mixed with a low density fuel.

LHV: Lower Heating Value

Lifting: Refers to tankers and barges taking on cargoes of oil or refined product at the terminal or transshipment point

Light Crude:  Crude oil with a low specific gravity and high API gravity due to the presence of a high proportion of light hydrocarbon fractions and low metallic compound

Light Ends: The more volatile products of petroleum refining; eg. butane, propane, gasoline

Marine Diesel Oil (MDO): Marine Diesel oil is a middle distillate fuel oil which can contain traces often percent (10%) or more residual fuel oil from transportation contamination and/or heavy fuel oil blending. The MDO does not require heated storage

MDO:  Marine Diesel Oil

Middle Distillate: The term applied to hydrocarbons in the so-called “middle range” of refinery distillation. Examples: heating oil, diesel fuels, and kerosene

Motor Gasoline: A complex mixture of relatively volatile hydrocarbons with or without small quantities of additives, that have been blended to form a fuel suitable for use in spark-ignition engines

MSDS: Material safety data sheet – a document that provides pertinent information and a profile of a particular hazardous substance or mixture. An MSDS is normally developed by the manufacturer or formulator of the hazardous substance or mixture. The MSDS is required to be made available to employees and operators whenever there is the likelihood of the hazardous substance or mixture being introduced into the workplace

Naphtha: A volatile, colorless product of petroleum distillation. Used primarily as paint solvent, cleaning fluid, and blendstock in gasoline production, to produce motor gasoline by blending with straight-run gasoline

Naphthenes: One of three basic hydrocarbon classifications found naturally in crude oil. Naphthenes are widely used as petrochemical feedstock. Examples are: cyclopentane; methyl-,ethyl, and propylcyclopentane

Neutralization number: The number that expresses the weight in milligrams of an alkali needed to neutralize the acidic material in one gram of oil. The neutralization number of an oil is an indication of its acidity

NPDES permit: National Pollutant Discharge Elimination System permit is the regulatory agency document issued by either a federal or state agency which is designated to control all discharges of pollutants from point sources into U.S. waterways. NPDES permits regulate discharges into navigable waters from all point sources of pollution

Olefins: A class of unsaturated paraffin hydrocarbons recovered from petroleum. Typical examples include: butene, ethylene and propylene

OSHA: The Williams-Steiger Occupational Safety and Health Act of 1970 (OSHA) is a law designed to protect the health and safety of industrial workers and treatment plant operators. It regulates the design, construction, operation and maintenance of industrial plants and wastewater treatment plants. The Act does not apply directly to municipalities, EXCEPT in those states that have approved plans and have asserted jurisdiction under Section 18 of the OSHA Act. Wastewater treatment plants have come under stricter regulation in all phases of activity as a result of OSHA standards. OSHA also refers to the federal and state agencies which administer the OSHA regulations

Oxidation: Combining elemental compounds with oxygen to form a new compound. A part of the metabolic reaction

Oxidizing agent:  Any substance such as oxygen and chlorine , that can accept electrons. When oxygen or chlorine is added to wastewater, organic substances are oxidized. These oxidized organic substances are more stable and less likely to give off odors or to contain disease bacteria

Outage: Space left in a product container to allow for expansion during the temperature changes it may undergo during shipment and application. Measurement of space that is NOT occupied in a drum

Ozonation: The application of ozone to water, wastewater, or air, generally for the purposes of disinfection or odor control.

Peristaltic pump: A type of positive displacement pump.

Petrochemical: An intermediate chemical derived from petroleum, hydrocarbon liquids or natural gas, such as: ethylene, propylene, benzene, toluene and xylene.

Petroleum:  A generic name for hydrocarbons, including crude oil, natural gas liquids, natural gas and their products

pH: pH is an expression of the intensity of the basic or acidic condition of a liquid. Mathematically, pH is the logarithm (base 10) of the reciprocal of the hydrogen ion concentration. The pH may range from 0 to 14, where 0 is most acidic, 14 most basic, and 7 is neutral. Natural waters usually have a pH between 6.5 and 8.5.

Phenol: An organic compound that is an alcohol derivative of benzene

PIB: Product Information Bulletin. General information on a product.

Pollution:  The impairment (reduction) of water quality by agriculture, domestic or industrial wastes (including thermal and radioactive wastes) to such a degree as to hinder any beneficial use of the water or render it offensive to the senses of sight, taste, or smell or when sufficient amounts of waste creates or poses a potential threat to human health or the environment

Polymer: A chemical formed by the union of many monomers (a molecule of low molecular weight). Polymers are used with other chemical coagulants to aid in binding small suspended particles to form larger chemical flocs for easier removal from water. All polyelectrolytes are polymers, but not all polymers are polyelectrolytes

Polymerization: Process of combining two or more simple molecules of the same type, called monomers, to form a single molecule having the same elements in the same proportion as in the original molecules, but having increased molecular weight. The product of the combination is a polymer

Pour Point:  Lowest temperature at which an oil will pour or flow under certain prescribed conditions

Purifier:  A machine used for a liquid-liquid separation in which the two intermixed liquids which are insoluble in each other have different specific gravities. Solids with specific gravities higher than those of the liquids can be separated off at the same time. A purifier bowl has two outlets; one for the light phase liquid and one for the heavy phase liquid.

Reagent: A pure chemical substance that is used to make new products or is used in chemical tests to measure, detect, or examine other substances.

Recycle: The use of water or wastewater within (internally) a facility before it is discharged to a treatment system

Reduced Crude Oil:  Crude oil that has undergone at least one distillation process to separate some of the lighter hydrocarbons. Reducing crude lowers its API gravity, but increases the handling safety by raising the flash point

Refinery: A plant used to separate the various components present in crude oil and convert them into usable products or feedstock for other processes.

Residual Slagging: Formation of hard deposits on boiler tubes and/or piston crowns, usually due to the presence of sodium, vanadium and sulfur

Sludge: Deposits in fuel tanks and caused by the presence of wax, sand, scale, asphaltenes, tars, water, etc.

Specific gravity: Weight of a particle, substance or chemical solution in relation to an equal volume of water at 15C.

Specific heat:  The quantity of heat required to raise the temperature of a unit weight of a substance by 1 degree; usually expresses as calories/gram/C or BTU/lb./F

Stabilize: To convert to a form that resists change. Organic material is stabilized by bacteria which convert the material to gases and other relatively inert substances. Stabilized organic material generally will not give off obnoxious odors

Static mixer:  A motionless mixer which has a series of fixed, geometric elements enclosed within a tubular housing. The internal elements impart flow division and radial mixing to the media flowing through the housing to produce a uniform dilution of the production

Straight-Run: Refers to a petroleum product produced by the primary distillation of crude oil, free of cracked components

Surfactant: Surface-active agent. The active agent in detergents that possesses a high cleaning ability. Used in a spray solution to improve its sticking and wetting properties when applied to plants, algae, or petroleum

TBN:  Total Base Number. ASTM D2896. This is measured in mg. KOH needed to neutralize an acidic solution through a reverse titration. TBN is the ability of the product to neutralize acid

Topped Crude Oil:  Oil from which the light ends have been removed by a simple refining process. Also referred to as “reduced crude oil”.

Toxicity: The relative degree of being poisonous or toxic. A condition which may exist in wastes and will inhibit or destroy the growth or function of certain organisms.

Ullage: The amount which a tank or vessel lacks of being full.

Vanadium Inhibitor: An organic and/or inorganic metal bearing chemical intended to chemically and/or physically combine with the compounds formed during combustion of heavy fuel oil to improve the surface properties of the treated ash compounds

Viscosimeter: A device for determining the viscosity of oil.

Vis-Breaking: A light thermal cracking process carried out on a fuel oil during the refining process to reduce product viscosity without blending

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