2. COOLING TOWER?
Cooling towers are a special type of heat exchanger that allows water and air to come in
contact with each other to lower the temperature of the hot water. During this process,
small volumes of water evaporate, lowering the temperature of the water that’s being
circulated throughout the cooling tower. In a short summary, a cooling tower cools
down water that gets over heated by industrial equipment and processes.
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3. TYPES OF COOLING TOWER
Cooling towers are generally classified either by build, heat
transfer methods and airflow generation methods. We will take a
look at each of the types of cooling towers.
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BUILD HEAT TRANSFER AIRFLOW
Package type
Field erection type
Dry cooling tower
Wet cooling tower
Natural draft
Mechanical draft
4. COMPONENTS OF COOLING
TOWER
1. Drift eliminator
2. Cooling tower nozzles
3. Fan motor
4. Fill
5. Cold water basin
6. Piping
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5. COOLING TOWER AT FFBL
TYPE FORCED DRAFT
COOLING WATER FLOW 36,800 m3
WATER INELT TEMPERATURE 42.3 ℃
WATER OUTLET
TEMPERATURE
33 ℃
TOWER BASIN RETENTION 15 minutes at design flow
NUMBER OF CELLS 10
EVAPORATION 500 m3/h
DRIFT LOSSES 0.2%
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6. COOLING TOWER PLANT
The cooling tower plant consists of:
a) One cooling tower and accessories
b) Cooling tower structure and fan stack
c) Water distribution system
d) Chemical dosing facilities
e) Cold water basin
f) Access platforms, walkways, stairs and handrails
g) Drift eliminators
h) Fills
i) Cooling water transfer pumps
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7. COOLING WATER TRANSFER
PUMPS
1) UREAAND UTILITIES PUMP
There are two water transfer pumps having following specs:
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TYPE VERTICAL TURBINE
CAPACITY 6900 m3/h
HEAD 40 m
OPERATION TWO X 50% (RUNNING IN PARALLEL)
8. COOLING WATER TRANSFER
PUMPS
2) AMMONIA PUMP
There are four ammonia pumps having following specs:
Three pumps are vertical centrifugal electric motor driven each
with a 5180 m3/h and 42 m head.
One pump is vertical centrifugal steam turbine driven 4680
m3/h and 30 m head..
All four pumps will operate in parallel.
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9. COOLING WATER TRANSFER
PUMPS
3) STAND-BY PUMP
One stand-by pump (common for both Urea/Utilities and
ammonia pumping systems) is installed. The pump is electric
motor driven 6900 m3/h and 40 m head.
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10. CHEMICAL DOSING
Zinc poly phosphate is used as corrosion/scale inhibitor and is
injected into the cooling tower basin. The zinc phosphate is
delivered in a liquid form and is fed as such. The dosing system is
skid mounted and will consist of:
One (1) polyethylene tank
Two (2) metering pumps, one as standby
Interconnecting pumps and valves (PVC or lined)
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11. POLYMERIC DISPERSANT DOSING
SYSTEM
Polymeric dispersant is used to maintain the phosphate solubility
in the zinc phosphate at 90% or better. The dispersant is injected
into the cooling tower basin. The polymeric dispersant is
delivered in a liquid form and is fed as such the dosing system is
skid mounted and will consist of:
One (1) polyethylene tank
Two (2) metering pumps, one as standby
Interconnecting piping and valves (PVC or lined)
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12. CHLORINATION SYSTEM
Chlorine is used to control biological and algae growth. The
chlorination system consists of:
Two (2) liquid chlorine cylinders
Vacuum regulators
Automatic switch over module
Chlorine gas analyzer
Controls with alarm contact with LCD indicators for power,
ready, malfunction alarm bar graph for concentration
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13. MAINTENANCE OF COOLING
TOWER
Goodway Technologies, a manufacturer of industrial cleaning
equipment, compiled a five-step list to optimize cooling tower
maintenance and cleaning:
1) Inspect towers at least monthly. Sediment, scale and slime can
lead to buildup and help Legionella grow and thrive. Regular
inspections will help determine when to schedule cleaning.
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14. MAINTENANCE OF COOLING
TOWER
2) Clean tower basin surfaces. If sediment is visible, the basin
needs to be cleaned and cooling tower vacuums make it easier to
remove contaminants without shutting down or draining your
system.
3) Descale the fill. The tower fill provides the perfect
environment for bacterial growth, especially Legionella. A
descaler will dissolve the scale and mineral deposits that
Legionella like to hide in, leaving the surface ready for cleaning.
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15. MAINTENANCE OF COOLING
TOWER
4) Clean the fill. A cooling tower fill cleaner will remove dirt and
debris and inhibit the growth of other bacteria when utilized in
conjunction with appropriate biocides.
5) Disinfect the tower. Cooling towers can be a dangerous
breeding ground for bacteria, which makes it important to reduce
the nutrients available for Legionella growth.
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