Giáo trình Thuật ngữ chuyên ngành Dầu và Khí

oleum products (usually lubricating 
oils and distillate fuels) by solvent absorption, chilling, and filtering. 
DIETHANOLAMINE A chemical (C4H11O2N) used to remove H2S from gas 
streams. 
DISTILLATE The products of distillation formed by condensing vapors. 
DOWNFLOW Process in which the hydrocarbon stream flows from top to 
bottom. 
DRY GAS Natural gas with so little natural gas liquids that it is nearly all 
methane with some ethane. 
Giáo trình Thuật ngữ chuyên ngành Dầu và Khí 43 
FEEDSTOCK Stock from which material is taken to be fed (charged) into a 
processing unit. 
FLASHING The process in which a heated oil under pressure is suddenly 
vaporized in a tower by reducing pressure. 
FLUX Lighter petroleum used to fluidize heavier residual so that it can be 
pumped. 
FOULING Accumulation of deposits in condensers, exchangers, etc. 
FRACTION One of the portions of fractional distillation having a restricted 
boiling range. 
FRACTIONATING COLUMN Process unit that separates various fractions of 
petroleum by simple distillation, with the column tapped at various levels to 
separate and remove fractions according to their boiling ranges. 
FUEL GAS Refinery gas used for heating. 
GAS OIL Middle-distillate petroleum fraction with a boiling range of about 
350°-750°F, usually includes diesel fuel, kerosene, heating oil and light fuel oil. 
HEADER A manifold that distributes fluid from a series of smaller pipes or 
conduits. 
HEAT As used in the Health Considerations paragraphs of this document, 
heat refers to thermal burns for contact with hot surfaces, hot liquids and 
vapors, steam, etc. 
HEAT EXCHANGER Equipment to transfer heat between two flowing 
streams of different temperatures. Heat is transferred between liquids or 
liquids and gases through a tubular wall. 
HIGH-LINE OR HIGH-PRESSURE GAS High-pressure (100 psi) gas from 
cracking unit distillate drums that is compressed and combined with low-line 
gas as gas absorption feedstock. 
HYDROCRACKING A process used to convert heavier feedstock into lower-
boiling, higher-value products. The process employs high pressure, high 
temperature, a catalyst and hydrogen. 
Giáo trình Thuật ngữ chuyên ngành Dầu và Khí 44 
HYDROFINISHING A catalytic treating process carried out in the presence of 
hydrogen to improve the properties of low viscosity-index naphthenic and 
medium viscosity-index naphthenic oils. It is also applied to paraffin waxes and 
microcrystalline waxes for the removal of undesirable components. This 
process consumes hydrogen and is used in lieu of acid treating. 
HYDROFORMING Catalytic reforming of naphtha at elevated temperatures 
and moderate pressures in the presence of hydrogen to form high-octane BTX 
aromatics for motor fuel or chemical manufacture. This process results in a net 
production of hydrogen and has rendered thermal reforming somewhat 
obsolete. It represents the total effect of numerous simultaneous reactions 
such as cracking, polymerization, dehydrogenation, and isomerization. 
HYDROGENATION The chemical addition of hydrogen to a material in the 
presence of a catalyst. 
INHIBITOR Additive used to prevent or retard undesirable changes in the 
quality of the product, or in the condition of the equipment in which the product 
is used. 
ISOMERIZATION A reaction that catalytically converts straight-chain 
hydrocarbon molecules into branched-chain molecules of substantially higher 
octane number. The reaction rearranges the carbon skeleton of a molecule 
without adding or removing anything from the original material. 
ISO-OCTANE A hydrocarbon molecule (2,2,4-trimethylpentane) with 
excellent antiknock characteristics on which the octane number of 100 is 
based. 
LEAN OIL Absorbent oil fed to absorption towers in which gas is to be 
stripped. After absorbing the heavy ends from the gas, it becomes fat oil. 
When the heavy ends are subsequently stripped, the solvent again becomes 
lean oil. 
LOW-LINE or LOW-PRESSURE GAS Low-pressure (5 psi) gas from 
atmospheric and vacuum distillation recovery systems that is collected in the 
gas plant for compression to higher pressures. 
NAPHTHA A general term used for low boiling hydrocarbon fractions that are 
a major component of gasoline. Aliphatic naphtha refers to those naphthas 
containing less than 0.1% benzene and with carbon numbers from C3 through 
C16. Aromatic naphthas have carbon numbers from C6 through C16 and 
Giáo trình Thuật ngữ chuyên ngành Dầu và Khí 45 
contain significant quantities of aromatic hydrocarbons such as benzene 
(>0.1%), toluene, and xylene. 
OLEFINS A family of unsaturated hydrocarbons with one carbon-carbon 
double bond and the general formula CnH2n. 
PARAFFINS A family of saturated aliphatic hydrocarbons (alkanes) with the 
general formula CnH2n+2. 
POLYFORMING The thermal conversion of naphtha and gas oils into high-
quality gasoline at high temperatures and pressure in the presence of 
recirculated hydrocarbon gases. 
POLYMERIZATION The process of combining two or more unsaturated 
organic molecules to form a single (heavier) molecule with the same elements 
in the same proportions as in the original molecule. 
PREHEATER Exchanger used to heat hydrocarbons before they are fed to a 
unit. 
PRESSURE-REGULATING VALVE A valve that releases or holds process-
system pressure (that is, opens or closes) either by preset spring tension or by 
actuation by a valve controller to assume any desired position between fully 
open and fully closed. 
PYROLYSIS GASOLINE A by-product from the manufacture of ethylene by 
steam cracking of hydrocarbon fractions such as naphtha or gas oil. 
PYROPHORIC IRON SULFIDE A substance typically formed inside tanks 
and processing units by the corrosive interaction of sulfur compounds in the 
hydrocarbons and the iron and steel in the equipment. On exposure to air 
(oxygen) it ignites spontaneously. 
QUENCH OIL Oil injected into a product leaving a cracking or reforming 
heater to lower the temperature and stop the cracking process. 
RAFFINATE The product resulting from a solvent extraction process and 
consisting mainly of those components that are least soluble in the solvents. 
The product recovered from an extraction process is relatively free of 
aromatics, naphthenes, and other constituents that adversely affect physical 
parameters. 
REACTOR The vessel in which chemical reactions take place during a 
chemical conversion type of process. 
Giáo trình Thuật ngữ chuyên ngành Dầu và Khí 46 
REBOILER An auxiliary unit of a fractionating tower designed to supply 
additional heat to the lower portion of the tower. 
RECYCLE GAS High hydrogen-content gas returned to a unit for 
reprocessing. 
REFLUX The portion of the distillate returned to the fractionating column to 
assist in attaining better separation into desired fractions. 
REFORMATE An upgraded naphtha resulting from catalytic or thermal 
reforming. 
REFORMING The thermal or catalytic conversion of petroleum naphtha into 
more volatile products of higher octane number. It represents the total effect of 
numerous simultaneous reactions such as cracking, polymerization, 
dehydrogenation, and isomerization. 
REGENERATION In a catalytic process the reactivation of the catalyst, 
sometimes done by burning off the coke deposits under carefully controlled 
conditions of temperature and oxygen content of the regeneration gas stream. 
SCRUBBING Purification of a gas or liquid by washing it in a tower. 
SOLVENT EXTRACTION The separation of materials of different chemical 
types and solubilities by selective solvent action. 
SOUR GAS Natural gas that contains corrosive, sulfur-bearing compounds 
such as hydrogen sulfide and mercaptans. 
STABILIZATION A process for separating the gaseous and more volatile 
liquid hydrocarbons from crude petroleum or gasoline and leaving a stable 
(less-volatile) liquid so that it can be handled or stored with less change in 
composition. 
STRIPPING The removal (by steam-induced vaporization or flash 
evaporation) of the more volatile components from a cut or fraction. 
SULFURIC ACID TREATING A refining process in which unfinished 
petroleum products such as gasoline, kerosene, and lubricating oil stocks are 
treated with sulfuric acid to improve their color, odor, and other characteristics. 
Giáo trình Thuật ngữ chuyên ngành Dầu và Khí 47 
SULFURIZATION Combining sulfur compounds with petroleum lubricants. 
SWEETENING Processes that either remove obnoxious sulfur compounds 
(primarily hydrogen sulfide, mercaptans, and thiophens) from petroleum 
fractions or streams, or convert them, as in the case of mercaptans, to 
odorless disulfides to improve odor, color, and oxidation stability. 
SWITCH LOADING The loading of a high static-charge retaining hydrocarbon 
(i.e., diesel fuel) into a tank truck, tank car, or other vessel that has previously 
contained a low-flash hydrocarbon (gasoline) and may contain a flammable 
mixture of vapor and air. 
TAIL GAS The lightest hydrocarbon gas released from a refining process. 
THERMAL CRACKING The breaking up of heavy oil molecules into lighter 
fractions by the use of high temperature without the aid of catalysts. 
TURNAROUND A planned complete shutdown of an entire process or 
section of a refinery, or of an entire refinery to perform major maintenance, 
overhaul, and repair operations and to inspect, test, and replace process 
materials and equipment. 
VACUUM DISTILLATION The distillation of petroleum under vacuum which 
reduces the boiling temperature sufficiently to prevent cracking or 
decomposition of the feedstock. 
VISBREAKING Viscosity breaking is a low-temperature cracking process 
used to reduce the viscosity or pour point of straight-run residuum. 
WET GAS A gas containing a relatively high proportion of hydrocarbons that 
are recoverable as liquids.