Why should circulating water be treated?
1.Scale: After the circulating water passes through the cooling tower, the water evaporates continuously, and all the ions brought by the replenishment water remain in the circulating water. The ion concentration continues to rise and becomes supersaturated; these excess ions crystallize and precipitate in the high temperature places in the system (condenser, heat exchanger), forming scale; The water quality in most parts of China is relatively hard. As the circulating water continues to concentrate, calcium carbonate will crystallize and precipitate on the heat exchange surface, forming scale.
2.Algae and slime: The circulating water has a moderate temperature and is rich in nutrients, which is very suitable for the growth of algae and other microorganisms. If it is not controlled in time, it will lead to water quality deterioration, produce slime, affect the heat dissipation of the cooling tower, and may block the condenser.
3.Corrosion: If the nutrients, chemicals, chloride ions, etc. in the water are out of control, it will cause corrosion of the pipes and heat exchangers, affecting the service life of the equipment.
Conventional treatment methods for circulating water – chemicals
- The commonly used anti-scaling method is to add chemicals, but the effect of anti-scaling agents is unstable and the condenser will still scale; if the water quality of the replenishing water is poor (such as groundwater), or the concentration multiple of the circulating water is high (> 5 times), the effect of the anti-scaling agent will decay rapidly, causing the condenser to scale;
- If the anti-scaling agent is not added enough, the equipment will scale; if the quality of the agent is poor, it will corrode the heat exchanger and pipelines;
- Anti-scaling agents (usually phosphates) will promote the growth of bacteria and algae, causing water quality to deteriorate;
- After adding anti-scaling agents to the circulating water, the phosphorus content will inevitably exceed the standard (0.5ppm). Environmental protection is becoming more and more stringent, and the use of phosphorus-free water treatment methods is an inevitable trend.
Heat exchanger fouling needs cleaning
The condenser is fouled and needs to be shut down for manual cleaning:
- Physical cleaning (cannon blasting) generally uses high-pressure water guns or pipe brushes, which often cannot be cleaned clean. If the scale is hard, chemical cleaning is required;
- Chemical cleaning generally involves adding acid, which will corrode the heat exchanger, cause leakage, and shorten the service life of the equipment;
If there is no scaling, there is no need to clean it. We have a better option – use electromagnetic methods instead of or in combination with chemical agents. After installing the frequency modulation scale inhibitor, the scaling problem of all heat exchange equipment in the circulating water system, including the chiller air compressor and other heat exchangers, can be solved.
