UFC 3-240-13FN
25 May 2005
of a reaction with its (environmental) surroundings.
Cycles of Concentration (COC) -- In a system in which water lost through evaporation
and blowdown is replaced with makeup water, COC is the ratio of the makeup quantity
to the blowdown quantity (COC = M/B). It is the number of times the makeup water is
concentrated in the system. The COC can also be calculated by dividing either the
conductivity or the chloride content of the blowdown by the conductivity or chloride
content of the makeup (COC = Condbd/Condmw).
Deaerator -- Device for removing non-condensable gases from the boiler. It may
operate on the principle of either heat or vacuum.
Deionization -- Complete removal of ions from water.
Demineralization -- Reduction of the mineral content of water by a physical or
chemical process; removal of salts.
Disinfection -- The process of killing most (but not necessarily all) of the harmful and
objectionable microorganisms in a fluid by various agents such as chemicals, heat,
ultraviolet light, ultrasonic waves, or radiation.
Dissolved solids -- (a) Solids, usually minerals, which are present in solution. (b) The
dried residue from evaporation of the filtrate after separation of suspended solids (SS).
Distribution Ratio (D.R.) -- This is a measure of the vapor/liquid ratio for a given
material. Extremely high and low values are generally unadvisable. A high D.R. results
in either high amine losses at any vents or little availability of amine at points of initial
condensation, or both. A low D.R. results in high amine losses in the blowdown.
the main process by which heat is removed from a cooling tower and steam is produced
in a boiler.
Feedwater -- Water being applied to the feedwater heater or to the boiler, consisting of
both makeup and condensate return.
Filming Amines -- Chemicals that form an impervious barrier between metal and the
steam condensate to prevent corrosion.
Foulants -- Deposition of materials normally in suspension. This includes silt, air-
scrubbed dust, microbiological residuals, reaction products from treatment, and
corrosion products.
Generic Chemicals -- A chemical identified and purchased by the recognized
chemical name, such as the International Union of Pure and Applied Chemistry (IUPAC)
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