Technical
COOLING TOWER WATER TREATMENT – UNDERSTANDING THE OPTIONS
By P . Thyse , technical manager at Allmech
Cooling towers require water treatment systems to ensure they operate optimally and last their designed service life .
Without water treatment , cooling tower water may be affected by organic growth , fouling , scaling , and corrosion . This can reduce plant productivity , cause downtime , and increase maintenance and repair costs significantly . The key is water treatment optimisation : the ability to not only apply the right chemistries but also to constantly monitor and control water quality and to keep it balanced at all times .
By monitoring pH , water temperature , electrical conductivity , microbiological activity , corrosion , chemistry levels and other variables you are able to increase production , reduce downtime , lower operating and chemical costs and reduce your operation ’ s impact on the planet . To control scale , corrosion , microbiological fouling , and foaming ; water quality must be maintained at all times , and the right microbicides must also be applied in the right doses .
Water treatment products can generally be divided into three groups : scale and corrosion inhibitors for open circuits , scale and corrosion inhibitors for closed circuits , and micro biocides . Solutions across these categories exist and are designed for each specific requirement .
SCALE AND CORROSION INHIBITORS When it comes to scale and corrosion inhibitors for open circuits , versatile products are on the market that control scale and corrosion equally well . These products are particularly effective where system control is erratic and when plant operating conditions tend to fluctuate . A wide variety of deposits can be controlled over an extensive pH range . Specially formulated solutions designed to reduce corrosion and scale formation in cooling and boiler water systems should be used . These are also useful in other systems where calcium carbonate scale and mild steel corrosion need to be prevented .
For closed circuits , other inhibitors are designed to control the corrosion of metals in such systems and are best for treating process cooling , hot water and chilled water systems , as well as glycol water systems . Such products contain steel and copper corrosion inhibitors to provide multi-metal corrosion control , plus pH buffering to minimise the effects of acidic conditions from ethylene glycol breakdown or acidic process leaks . Hardness
An example of corrosion that has occurred on a cooling tower .
Allmech www . refrigerationandaircon . co . za RACA Journal I July 2022 49