60. REBOILER - A part of a fractionation tower designed to supply all or a portion of
the heat to the tower. Liquid is withdrawn from the bottom of the tower and heated
in the reboiler. The vapors formed are returned to the tower. The remaining liquid
may or may not be returned to the tower. Heat may be furnished by oil circulated
through a heater, bottoms from some other tower, or by steam.
61. RECYCLE - Continuous circulation without withdrawing a product from the
system, or that part of the product that is returned to the system.
62. REFLUX - Liquid that is returned to a fractionating tower to control temperatures
and increase the efficiency of separation.
63. REGULATOR - A valve which directly controls the flow of liquid or gas through
a line, usually actuated by an instrument to control temperature, pressure, level, or
flow conditions.
64. RUNNING TANK - A tank to which a product from a unit is continuously
pumped or from which a unit is charged.
65. SAFETY VALVE - A preset valve to release excessive pressure on a vessel or
system.
66. SODIUM HYDROXIDE (NaOH) CAUSTIC SODA - Lye used in treating oils.
67. SOUR - Ill smelling; a petroleum fraction or gas having a bad odor caused by
mercaptans or hydrogen sulfide.
68. SPLIT TUBE - A crack or break in a heater or exchanger tube due to mechanical
failure -- corrosion or overheating. If this occurs in a heater, it is usually followed
by a fire.
69. STABILIZER - A tower that separates high vapor pressure hydrocarbons from
gasoline so that the gasoline will meet vapor pressure specifications.
70. STATIC PRESSURE - Acting by mere weight without motion.
71. STEAM-LIVE - Water vapor which does not contain entrained water droplets
(usually high pressure).
72. STEAM-EXHAUST - Low pressure steam which has already been used for some
purpose (from a pump, compressor or electric generator).
73. STEAM-SUPERHEATED - Water vapor heated above the saturation temperature
at a given pressure. Usually used in towers, heaters, strippers, etc.
74. STEAM-WET - Steam containing entrained water.
75. STRAIGHT RUN - A material produced by distillation of crude oil without
appreciable cracking or alteration of the molecules in the product.
76. STRIPPER - A vessel which strips off the light ends of a side cut from the main
fractionating tower. Superheated steam is usually injected into the stripper bottom
to improve this separation.
77. SUPERHEATER - A heating apparatus (usually tubes) which imparts to a material
more heat than is required for vaporization.
78. SURGE DRUM - A vessel or accumulator which serves as a reservoir for liquid
flowing through a system, thereby overcoming fluctuations in the rate of flow.
79. SWEET - Having a good odor. Negative to the doctor test.
80. THIEF - A device for drawing samples of oil from a tank at various levels.
81. THIEF ROD - A rod used to measure the depth of water in a tank.
