Tired of being surprised by cooling tower changes?

Inefﬁcient or unreliable cooling towers can severely

impact production units that rely on a consistent supply

of cooling water. Making up for limited cooling capacity

can erode your proﬁts and increase your energy costs

signiﬁcantly. In fact, experts estimate that improperly

maintained cooling towers consume 2.5 to 3.5 percent

more energy for each degree increase in cooling water

temperature.

Warmer water raises the risk of limited cooling for

heat exchangers and condensers, which can require

a slowdown to compensate for decreased cooling

capacity. Fouling, corrosion, and microbiological growth

due to poor water quality can also reduce throughput,

especially on hot days when cooling capacity is limited.

And in freezing weather, ice buildup can damage cooling

tower fans.

Any unexpected failure of tower fans, supply pumps, or

heat exchangers can not only affect cooling capacity, but

also drive up maintenance costs. Fortunately, Emerson’s

Essential Asset Monitoring solution for cooling towers

can help you get those lost proﬁts back.

Anatomy of a Cooling Tower Failure

Common Threats to Induced-Draft Cooling Tower Health

Root Cause

Equipment

Impact

Process

Impact

Environmental

Impact

Business

Impact

Undetected

Conditions

Avoidable

Consequences

Abnormal

Situations

Health hazards

Fires

Vapor release

Reportable

incidents

Personnel

health impact

Product to

storage too hot

Fouling of process

exchangers

Hydrocarbons

collect in basin

Belt/

coupling/

bearing

failure

Increased

corrosion

Scaling

Excessive

in gear

teeth

Cooling tower

failure

Blockage of cooling

tower piping and

distributors

Increased vibration

Basin overflow

Bacterial and

microbiological

growth

Process

slowdowns/

shutdowns

Increased cost

due to increased

water and

chemical use

Additional cost

for rental

cooling tower

I d t

Reduced

equipment life

due to higher

cooling system

corrosion rates

Increased

maintenance costs

Reportable

Reduced

tower capacity

and increased

energy cost

Improper blowdown

Process exchanger

leak

Stuck/poorly

adjusted fill valves

adjusted

fill

valves

Inaccurate level

indication

Normal bearing/

coupling/belt

wear and tear

High cooling water

temperature

Reduced cooling

capacity

Shaft misalignment

Resonance

frequency

Chipped, broken

or worn gear teeth

Inadequate water

quality monitoring

Poor pH/

total dissolved

solids control

Inadequate

chemical addition

IMPROPER BLOWDOWN AND MAKEUP

To control concentration of dissolved solids and maintain optimum water

level on the tower basin, new water needs to be added to the cooling tower

(makeup) and a portion of the concentrated water needs to be discharged

(blowdown). Improper blowdown and makeup may lead to reduced pH,

corrosion, and higher water consumption.

RESTRICTIONS IN WATER FLOW

Restrictions of the pump’s suction can result in cavitation

or low cooling water supply pressure to the plant. Root

causes include a plugged suction strainer or valve issues.

BIOLOGICAL GROWTH

Biological organisms coat heat transfer surfaces and restrict water ﬂow. It can lead

to increased corrosion and potential health issues if bacteria is released through

the drift. Biological growth is controlled by favorable water temperature and pH.

SCALING

As water evaporates in cooling

towers, solids settle on heat

exchanger surfaces, reducing

heat transfer. Root causes include

increased water alkalinity and

higher concentration of total

dissolved solids.

HYDROCARBON LEAKAGE

Hydrocarbons may leak into the

circulating water, and leaks caused

by mechanical failures can be

catastrophic. Early detection of

abnormal conditions can help

avoid leaks and their consequences.

CORROSION

Common problems from corrosion include reduction in heat transfer and water

ﬂow, resulting from a blockage of pipes, valves, or strainers. Root causes include

alkalinity and acidity of water, and higher concentrations of total dissolved

solids.

HIGH VIBRATION AND INCREASED BEARING

TEMPERATURE

Excessive vibration and rising temperature can lead to

bearing failure and damaged pump seals. Pump failures

and fan trips result in reduced unit throughput and

cooling capacity. Root causes include bearing wear,

shaft misalignment, or inadequate lubrication.