REYMSA COOLING TOWERS, INC.
www.reymsa.com
The
All-Fiberglass
Cooling Towers
41
Operation
C.3.2. SCALE FORMATION
Scale is the most widely-known water-caused trouble. Indeed the term is so familiar that it is often applied
incorrectly to all solid accumulations in water systems. Scale is but a single type of fouling; others being
sedimentation, corrosion, slime, etc. a true scale forms by crystallization of a dissolved salt when its
concentration exceeds its solubility.
The most common formed scale consists of:
▪ Calcium carbonate (lime scale)
▪ Calcium sulfate & silica
▪ Algae growth, slime, and other micro-organisms
C.3.3. BIOLOGICAL GROWTH
The growth of algae, slime and other micro-organisms in cooling systems are frequently spoken of and
handled as though they were a single word and single problem. Algae require sunlight for their growth,
which can be prevented by reducing the sunlight exposure. Minimizing the development of algae and
bacterial slimes is important because they reduce the heat transfer and system capacity, decrease cooling
water ow, localize corrosion, and serve as a mortar for permitting rapid build-up of deposits consisting of
an agglomeration of sediments, corrosion products, and scale.
The aim in cooling water treatment is microbiological control to avoid signicant slime or algae growth, not
the almost impossible goal of maintaining circulating water completely sterile. The many treatment chemicals
available for microbiological control in Closed Circuit Fluid Coolers include chlorine and other compounds
which yield available chlorine, some of these compounds have broad spectrum effectiveness and others are
specic for a more limited range of organisms.
Periodic measurement of the overall bacterial population of the water is recommended to maintain a
biological control, via culturing techniques and visual inspections for evidence of bio-fouling.
Finally, whenever agrant microbiological growths develop, chemical or mechanical cleaning must be included
along with micro biocide treatment in any effective program for promptly re-establishing microbiological
control.
Closed Circuit Fluid Cooler must be cleaned periodically to prevent the growth of bacteria
including legionella pneumophica, to avoid the risk of sickness or death.
CAUTION
C.3.1. SUSPENDED SOLIDS
Sedimentation of solid materials occurs in the Tower basin, pipes and equipment as a product of corrosion,
mill scale particles, silt or y ash scrubbed from air by the Closed Circuit Fluid Cooler. It is recommended that
every Closed Circuit Fluid Cooler is tted with a solid separator. REYMSA offers a centrifugal separator as
a design option for suspended solid control (see Figure C-8).
Figure C-8: Filtration system
Pump
Pump
Centrifugal
Separator
Filter
Control Panel
From the
System
To the
System
Process
To Next Page
Loading...