Page 278 - Pipeline Rules of Thumb Handbook

Gas—General 265

Glossary of common gas industry terms

(italics denote cross reference)

absolute pressure gauge pressure plus atmospheric connection charge an amount to be paid by the customer
pressure. in a lump sum, or in installments, for connecting the
associated gas see preceding page. customer’s facilities to the supplier’s facilities.
atmospheric pressure the pressure of the weight of air and contract demand the volume that the supplier of gas service
water vapor on the surface of the earth. Approximately 14.7 agrees to deliver and, in general, the amount that the
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lbf/in. at sea level. customer agrees to take or pay for.
blue water gas also called “water gas.” Made in a cyclic cubic foot and cubic meter (gas) common units of mea-
process in which an incandescent bed of coke or coal is surement of gas volume. They are the amounts of gas
alternately subjected to blasts of air and steam. The gas required to fill a volume of one cubic ft or one cubic meter
consists mainly of equal proportions of carbon monoxide under stated conditions of temperature, pressure and water
and hydrogen and has a gross heat content of about vapor content.
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300Btu/ft (see also carbureted water gas). customer charge a fixed amount to be paid periodically by
British thermal unit the heat required to raise the temper- the customer without regard to demand or commodity
ature of one lb of water 1°F. consumption.
burner capacity the maximum Btu/hr that can be released cycling or recycling the process by which a non-associated
by a burner while burning with a stable flame. gas reservoir is produced only for the recovery of conden-
calorie the quantity of heat required to raise the tempera- sate. The gas, after removal of the condensate, is
ture of one gram of water 1°C (centigrade). reinjected into the formation.
calorific value the quantity of heat released by the com- daily average send-out the total volume of gas delivered
bustion, in a calora meter at constant pressure of one during a period of time divided by number of days in the
atmosphere, of a unit quantity of fuel measured un- period.
der given conditions. In the case of gas, the conditions of daily peak the maximum volume of gas delivered in
temperature, pressure, and water vapor content under any one day during a given period, usually a calendar
which the unit volume was measured affect the calorific year.
value. degree day a measure of the extent to which the mean daily
calorimeter an instrument for determining the heating value temperature falls below an assumed base, say 65°F. Thus
of a fuel. each degree by which the mean temperature for any day is
carbureted water gas (carbureted blue gas) the gas less than 65°F would represent one degree day. (In Conti-
resulting from the enrichment of blue water gas during its nental Europe, °C are used instead of °F, and the assumed
manufacture by a simultaneous process of light distillate, base temperature is generally taken as 16°C equivalent to
gas oil or fuel oil gasification. The gas has a gross heat 60.8°F.)
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content of about 500 to 550Btu/ft . demand (load) rate of flow of gas in a specified time
city gate a measuring station, which may also include pres- interval, usually expressed in cubic ft (or cubic meters) per
sure regulation, at which a distributing gas utility receives hour, per day or per year.
gas from a natural gas pipeline company or the transmis- demand charge that portion of the charge or rate
sion system. for gas service based upon the customer’s demand
coal gas or coke oven gas a manufactured gas made by characteristics.
destructive distillation (“carbonization”) of bituminous coal distribution company or gas utility a company which
in a gas retort or by-product coke oven. Its chief compo- obtains the major portion of its gas operating revenues from
nents are methane (20 to 30%) and hydrogen (about 50%). the operation of a retail gas distribution system and which
This gas generally has a gross heating value of 500 to 550 operates no transportation system other than incidental
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Btu/ft . When the process takes place in a closed oven (with connections to a transportation system of another company.
gas as a by-product of coke production) it is generally desig- For purposes of American Gas Association (AGA) statistics,
nated as “Coke Oven Gas,” and when produced in retorts a distribution company obtains at least 95% of its gas
it is called “Coal Gas.” operating revenues from the operation of its retail gas
commodity charge that portion of the charge or rate based distribution system (see also transmission company).
upon the total volume of gas consumed or billed. distribution system feeders, mains, services, and equipment
condensate a liquid/hydrocarbon mixture of 45 to 65° API which carry or control the supply of gas from the point or
gravity, which may be recovered at the surface from some points of local supply (usually the city gate station) to and
non-associated gas reservoirs. including the consumer meters.