Questions regarding circulating water technology issues
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Dear teachers, I have a question: 1) What is the maximum temperature allowed for industrial circulating water in design? Some people say that scaling is likely to occur above 40°C. 2) What is the relationship between the lowest temperature that the outlet water of a circulating water cooling tower can theoretically reach and the local wet-bulb temperature? Thank you!
1) The return temperature of the circulating water should not exceed 50°C; scaling usually occurs at this temperature, and it is Of course related to the quality and turbidity of the circulating water. 2) The lowest temperature that the circulating water can reach is the local wet-bulb temperature, but due to factors such as heat exchange efficiency, it is generally about 4°C higher than the local wet-bulb temperature
please refer to GBT50746
High temperatures can accelerate bacterial reproduction; there is silt in the circulating water, and at that temperature it’s easy for an environment suitable for bacteria to develop – along with temperature, the silt present in that environment, and nutrients such as iron. Legionella pneumophila can also secrete mucus, which leads to the formation of scale. This facilitates the creation of oxygen concentration gradients, resulting in oxygen corrosion; over time, ulcer-like lesions may appear on the metal pipe walls
Local wet-bulb temperature, ambient temperature, and selection of cooling towers. Selection of closed-type cooling towers. Use of chemical dosing and physical scale removers.
The local wet-bulb temperature represents the limit for temperature drops