Operator Dictionary (B)

Now we continue with some of the terms that we often encounter when working…

BACK PRESSURE

1. The pressure on the outlet or downstream side of a flowing system.

2. In an engine, the pressure which acts adversely against the piston, causing loss of power.

BAFFLE

A partial restriction, generally a plate, located so as to change direction, guide the flow, or promote mixing within the equipment in which it is installed.

BALANCED DRAUGHT

A method of furnace air control using both forced and induced draught fans.

BAR OVER

To manually or mechanically rotate a compressor or turbine to ensure free movement or enable even heating/cooling.

BAROMETER

An instrument employed to determine atmospheric pressure.

BAROMETRIC CONDENSER

A device for condensing steam by direct contact with water. It produces a partial vacuum in refinery equipment such as a vacuum distillation unit.

BAROMETRIC LEG

Water filled tube for sealing vacuum systems.

BARREL

A standard measure of crude oil quantities; equivalent to 35 imperial gallons, 42 US gallons or 159 litres.

BASIC SEDIMENT AND WATER

The heavy material which collects in the bottom of storage tanks, usually composed of oil, water, and foreign matter. Also called bottoms, bottom settlings, etc. It is measured in all incoming feedstocks.

BATCH

Any quantity of material handled or considered as a unit in processing.

BATCH PROCESS

Any process in which a quantity of material is handled or considered as a unit. Such processes involve intermittent, as contrasted to continuous operation.

BATTERY

A series of individual items of refinery equipment operated as a unit.

BATTERY LIMITS

A term used when a unit or a battery is to be built in a refinery by an outside contractor or construction company. It specifies the area within which the contractor shall supply all services, and defines the limits beyond which this shall be done by the refinery. Also defines plant interface limits.

BEARING

A support for holding a shaft in its correct position.

Examples: journal bearings to confine radial motion, thrust bearings to control axial movement, and "rolling element" bearings which are used in both services.

BENZENE C6H6

The parent compound of the aromatic hydrocarbon series. It is used in the manufacture of a large number of chemicals including phenol, styrene, detergent alkylate and insecticides and is a major component of platformate.

BIOCHEMICAL OXYGEN DEMAND (BOD)

Important water test that shows the amount of bio-degradable matter in the water. Amount of oxygen required by aerobic organisms for breakdown of organic matter in water over a 5 day period.

BIODEGRADATION

Degradation of solid materials by bacterial consumption.

BIOTREATER

Process for biological degradation of effluent water.

BITUMEN

A non crystalline solid or semi solid cementitious material derived from petroleum, consisting essential of compounds composed predominantly of hydrogen and carbon with some oxygen and sulphur, it gradually softens when heated. Bitumen’s are black or brown in colour. They may occur naturally or may be made as end products from the distillation of, or as extracts from, selected petroleum oils.

BLACK PRODUCTS

Fuel oils, bitumen’s and residues.

BLEEDING

Divert or release a small portion of the material contained in a line or vessel, usually by opening a valve slightly.

BLEND

Any mixture prepared for a special purpose, e.g. the products of a refinery are blended to suit market requirements.

BLENDED FUEL OIL

A mixture of residual and distillate fuel oils.

BLENDING

Mixing of the various components in the preparation of a product of required properties.

BLENDING STOCK

Any of the stocks used to make commercial gasoline. These include: straight run gasoline, cracked gasoline, and synfuel among others.

BLENDING VALUE (ANTI KNOCK)

Some anti knock blending agents possess the property of apparently increasing the rated octane number of certain gasoline base stocks to a higher octane number than their own value in terms of octane numbers. This property is known as the blending value.

BLOCK VALVE

A valve used for isolation of equipment.

BLOCKED OPERATION

The use of a single process unit alternately in more than one operation.

BLOWBACK

A system in which a liquid or a gas is continuously bled through the lead lines of an instrument meter into the main line. This prevents the main line fluid from coming in contact with the meter body, thus eliminating vaporisation, corrosion or plugging.

BLOW BY

In internal combustion engines, the escape of combustion gases or unburned fuel from the combustion chamber past the pistons and rings into the crankcase during the power stroke or the compression stroke.

BLOWDOWN

The act of flushing or clearing a piece of pressurised equipment by blowing to a drain (or similar). Term is often used by Boilermen, continuos blowdown indicating blowdown from the Steam Drum or Scum level, and Intermittent Blowdown from the bottom header of a boiler.

BLOWER

Usually an enclosed fan used in a forced/induced/balanced draught furnace to provide the combustion air.

BLOWN BITUMEN

A type of bitumen prepared by the oxidation of short residues, normally by blowing air at an elevated temperature.

BLUE SMOKE

A blue exhaust smoke from a diesel engine, indicating that only a part of the fuel is being burned; also called cold smoke.

BOILING POINT (AT A GIVEN PRESSURE)

The temperature at which a liquid, contained in a closed vessel under a given pressure, will form a first bubble of vapour on the addition of heat. Further heating of the liquid at its boiling point results in evaporation of part or all of the liquid.

BOILING RANGE

Petroleum products (which are mixtures of many compounds, each having a different boiling point) do not have a simple boiling point but have a boiling range instead, i.e. the temperature range from boiling point to dew point.

BOMB

A small pressure vessel, such as used for taking samples of HP gases and LPG.

BOND

1. Chemically, a unit link between atoms. In graphic chemical formulas, it is often represented by a short line or dash.
2. Electrically, a common grounding system e.g. Bonding wires used between fuel tanker and petrol station ground tanks or airport delivery systems and aircraft.

BOOSTER STATION

An auxiliary station consisting of suitable storage tanks, motive power and pumps for pumping oil through pipelines.

BOTTLED GAS

Ordinarily, butane or propane, or butane propane mixtures, liquefied and bottled under pressure for domestic use.

BOTTOMS

The bottom product from a distillation of petroleum; also the liquid layer left in a tank or similar container after draining to the level of the pump suction.

BOX IN

To isolate a piece of equipment, usually by block valves.

BOX UP

The act of closing up a piece of refinery equipment following construction, maintenance, inspection etc.

BRAKE HORSEPOWER

That horsepower delivered by an engine to a brake or dynamometer. It is less than the indicated horsepower by the amount lost in transmission bearings, gear teeth, belts, etc.

BREAKER POINT

The point of contact actuated by a cam to break the primary circuit in the ignition system and thereby cause a current surge in the secondary circuit which produces the spark.

BREATHING

When a storage tank containing volatile products is heated by solar radiation, some of the liquid contents evaporate. The excess vapour thus formed is blown out to the atmosphere. On cooling, the less volatile components of the vapour contents condense and a slight vacuum is created, causing air from outside to be sucked into the tank. This double action is referred to as "breathing" of the tank. The movement of gas (oil vapours or air) in and out of the vent lines of storage tanks as a result of alternate heating and cooling.

BRINE

Water which is nearly saturated with salts.

BRITISH THERMAL UNIT (BTU)

The quantity of heat required to raise the temperature of 1lb of water through 1°F. 1.000 Btu = 252 kcal. 2.50 BRITOLITE A drying solvent used by BP. Manufactured from hydrocracked Naphtha and Tops.

BUFFER

1. A vessel for temporary storage of liquid (buffer drum).

2. A chemical used to maintain another within set limits of (e.g.) pH.

3. A device to polish the floor.

4. An old Navel name for a person in-charge of the deck of a Ship.

BUG COUNT

Microscopic estimation of active bacteria in a sample.

BULK CRUSHING STRENGTH

Test to determine the mechanical strength of a catalyst.

BULK DENSITY

The weight of solid particles which can be held by a container of known dimensions compared to the weight of water which can be held by the same container.

BUND WALL

Same as Fire Wall.

BUNKER FUEL

Any fuel oil or diesel fuel taken into the bunkers of ships.

BURNING OIL

An illuminating oil, such as kerosene, mineral seal oil, etc. suitable for burning in a wick lamp.

BUTANE C4H10

Commercial butane is a mixture of two gaseous paraffins, normal butane and isobutane. When blended into gasoline in small quantities it improves volatility and octane number. Butane can be stored under pressure as a liquid at atmospheric temperatures ("bottled gas") and it is widely used for cooking and domestic heating.

BUTANE DE ASPHALTING

A solvent extraction process whereby a short residue is split into components having low (D.A.O.) and high (Asphalt) asphaltic content by contact with liquid butane.

BYPRODUCT

A secondary or additional product not of primary importance. (e.g. Sulphur).