Technical assistance: Pretreatment of heat pump circulating water
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This post was last edited by hesonchang214 on 2009-8-15 at 11:57. The circulating water used in our company’s heat power systems is quite special: its total hardness exceeds 3500, calculated as calcium carbonate, and the chloride concentration is over 4000. Water with such high hardness tends to cause scaling on heat exchangers. Conventional chemical treatment methods are ineffective in this case. Our company hopes to carry out pre-treatment of the water to reduce its temporary hardness to around 1000. Is there any manufacturer capable of handling this task? You can contact me; my email is ach2001@163.com
What is the water volume? For such high hardness levels, it is more appropriate to use chemical methods for softening (such as direct lime softening or lime + soda ash softening), as this requires less investment; only a dosing tank and a sedimentation tank are needed. For other ion exchange and membrane treatment methods, the hardness is too high, so they are not very suitable.
If the alkalinity is high, it can be treated with lime. The high chloride ion concentration is likely due to the high chloride ion level in the incoming water. Since the circulating water system has a concentration multiplication factor of around 2-3, the chloride ion concentration in the circulating water is 2-3 times that of the incoming water ； In other aspects, the amount of disinfectant added is very small (the dosage is specified in ppm, and such an amount cannot affect the concentration of chloride ions) ； Therefore, it is still necessary to consider the approach from the perspective of water intake, as well as looking at the concentration ratio of your system ； The only methods for removing chloride ions are ion exchange or reverse osmosis; other chemical displacement methods are too costly!
Our company’s heat and power plant requires approximately 60 m3 of water per hour for make-up water, with a hardness level of around 1500. It seems that just building two tanks won’t be sufficient to meet the demands