NIAGARA
Niagara Blower Heat Transfer Solutions
673 Ontario St., Buffalo, NY 14207
Phone: (716) 875-2000 ~ Fax: (716) 875-1077
WATER TREATMENT
For
Wet Surface Air Coolers (WSAC’s)
A common cause of loss of capacity is the fouling of cooling or condensing coil surfaces with scale either due to
inadequate blow-down rates or biological growth. Blow-down should be regulated to keep dissolved and
suspended solids below a concentration at which they precipitate out onto the coil. Normally, a small steady
stream will keep solids concentration within satisfactory limits.
Niagara Blower Company cannot assume any responsibility, either direct or contingent, for the formation of scale
on heat exchanger surfaces or corrosion of any metals in the system. However, the Company recognizes the
importance and necessity of a cooling water treatment program to:
1. Prevent scale
2. Minimize corrosion
3. Arrest the growth of algae, slime, etc.
4. Prolong the life of the equipment
If these objectives are realized, the program will assure maximum reliability, continuing high efficiency and
minimum maintenance of the WSAC unit.
To achieve long equipment life with galvanized tubes, the circulating spray water flowing over the tube bundle
and inside the basin should not exceed the following:
pH 6.5 – 9.0
Total calcium hardness 600-1000 ppm
Total Alkalinity 2000 ppm
Conductivity 5000 umho
Total dissolved solids 3500 ppm
Chlorides 750 ppm
Total hardness 1000 ppm
The above ranges are to be used as a guideline only, additional chemical agents and/or alternate tube materials,
such as 304 SS, 316SS, duplex stainless steel (alloy 2205) and titanium, may be considered for more agressive
conditions.
A standard water treatment program should consist of at least the following:
1. Scale and corrosion inhibitor – Nalco 8365 plus or equivalent. Nalco 8365 Plus is an “all organic”
corrosion and deposit control program for open recirculating cooling water systems. The “all organic”
program is designed to operate at high alkalinities, minimizing or eliminating the need for acid feed.
2. Biocide – Nalco STABREX or equivalent. STABREX is a stabilized bromine which minimizes reactions with
organic contamination and organic inhibitors.
The chemicals above typically meet all discharge requirements for any publicly owned treatment works.
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NIAGARA
Niagara Blower Company
673 Ontario St., Buffalo, NY 14207
Phone: (716) 875-2000 ~ Fax: (716) 875-1077
Niagara Blower Company's comments on the subject of water treatment and compatible materials of
construction are for reference only. Material selection must be a combined effort between the customer,
Niagara Blower and a qualified water treatment company such as a Nalco.
It should be recognized that the foregoing suggestions are most general in scope. As equipment manufacturers,
we cannot foresee all possible developments in relation to water treatment in every situation. It is the
responsibility of the purchaser to provide proper make-up water and a suitable cooling water treatment program.
In view of the importance of the water treatment program, we urge you to consider the services of a reputable
organization with proven ability for successful performance in the water-conditioning field. Such an organization
must be able to provide the personalized services of reliable qualified engineers to assure the success of the
water treatment program. Niagara has long-standing relationships with two of the largest water treatment
companies in the world. Nalco has created water treatment regiments for various WSAC applications throughout
the world and will gladly assist any customer in their water treatment evaluation.
Total water make-up (GPM) = Evaporation + Blow-down
Evaporation rate (GPM) = Total Heat Load (BTU/hr) / 500,000
Cycles of Concentration = Evaporation rate / blowdown +1
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