Jin-Hui Plastics Industrial Co., Ltd.

Relationship between limescale and cooling tower

Operating principle of cooling tower

Limescale is a critical problem when cooling equipment, cooling water circuit will be blocked to result in machine halt. Therefore, customers often ask us how to change water quality or what equipment customers should set up to get rid of limescale and calcium carbonate. In fact, the reason that limescale builds up on equipment is not only water quality. The most important reason usually comes from cooling tower. (Know the operating principle of closed circuit cooling tower)

Cooling tower utilizes the principle of atmospheric evaporation that discharges heat energy produced from fan operation to cool equipment. At same time, water has continuously been extracting by pump to supply splashing water loss. However, the principle also brings about many problems. The most common problem is limescale buildup from calcium carbonate.

Why limescale accumulate on cooling tower?

At first, let's figure out what the calcium carbonate is.

Calcium carbonate, is a metal ion, exists in underground water and tap water. When exceeding a certain amount of concentration, calcium carbonate will react with heat to form limescale. It is called CaCO3 limescale.

When engaging in heat dissipation, cooling tower continuously repeats this limescale formation process:

Cooling tower operates►Cooling water enters equipment to lower temperature►Heat evaporates cooling water►New cooling water is supplied to cooling tower►Increase in mineral content in water►Cooling water again enters equipment to lower temperature ► Limescale accumulation►Decrease the cooling efficiency►Rise in limescale as times passed

Limescale Buildup Timeline (Calcium carbonate concentration changes according to different areas)

Cooling tower circulating time Production facility cooling water circuit Machine equipment efficiency Calcium carbonate concentration
First day Calcium ion doesn't calcify Good Normal value
First week  Calcium ion doesn't calcify Good Normal value
First month Calcium ion start calcifying Good Higher than 100ppm, saturation
Third month Calcium carbonate adheres to heat exchanger Moderate Supersaturation, encounter heat to form limescale
First year Blockage on heat exchanger, need acid-washing (heat exchanger cleaner?) Low Supersaturation, encounter heat to form limescale

When cooling tower operates, calcium carbonate water has also been supplying and finally causes the increase in calcium carbonate concentration. While cooling water with high calcium carbonate concentration enters into equipment, it is easy to deposit limescale on heat exchanger and water pipeline. This eventually contributes to decreasing heat transfer efficiency and machine halt.

How to isolate limescale from equipment?

We are usually eager to change water quality in order to get rid of limescale problem. However, no matter how to change water quality, impurities concentration will gradually accumulate in cooling system, enter into production equipment, and finally cause in blockage of water pipeline. To solve limescale problem, it is necessary to consider how to prevent calcium carbonate from entering into production equipment.

Contact Jin Hui

For more information with regard to closed circuit cooling tower, please continue to browse Jin Hui official website (SCT-Closed Circuit Cooling Tower) or contact us by phone : +886-4-26937836. Jin Hui will serve you as soon as we can. (SCT series Closed circuit cooling tower)