Technical assistance: Scale inhibitor for circulating water
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This post was last edited by hesonchang214 on 2014-1-27 08:45. Dear sea friends: Is the scale inhibitor used in your company’s circulating water organic phosphorus or something else? How is it working? 1 Total circulating water volume, M3/h: 2 Scale inhibitor: 3 Control parameters: 4 Performance: The title can be copied and pasted when replying. This post was last edited by Fan Zhou Wu Hu on 2009-3-13 20:59.]
Most of the agents that are widely used at present are organic phosphonate scale inhibitors, with addition levels ranging from 20 to 100 ppm. Their effectiveness is certainly high; otherwise, such products wouldn’t be in use. Common control parameters include: total phosphorus, concentration ratio, conductivity, total hardness, total alkalinity, SS, pH value, etc.
Thank you for participating. Is the total phosphorus level to be controlled at 20 PPm? Is it too low?
They are generally organophosphorus scale inhibitors. The control indicators were explained in quite detail upstairs.
That is the dosage concentration; the total phosphorus level will not be this high.
Scale inhibitors for circulating water are generally organic phosphates. Based on requirements such as water quality supplementation, concentration ratio, and process conditions, the dosage is 30–50 mg/L of the supplementary water volume, to be added continuously. We add 26 m3/L of water, with approximately 25 Kg added per day. The general control parameters for water quality include a concentration ratio of 2–4, and total phosphorus levels of 3–8 mg/L; these are parameters that are closely related to the dosage of scale inhibitors. Of course, there are other indicators as mentioned by friends above.
Total phosphorus control is generally maintained at 2-4; for cases with a higher concentration factor, it is kept between 5-7. 20 ppm refers to the dosage of chemicals added. Some manufacturers use large amounts of chemical agents, but the effective concentration is low; whereas with smaller amounts used, the effective concentration is high. Even when 20 ppm of such agent is used, the total phosphorus level cannot be kept below 5–7 ppm. Excessively high levels of total phosphorus, due to the hydrolysis of organic phosphines, lead to high concentrations of phosphate ions, which in turn increases the likelihood of calcium phosphate scale formation. Therefore, the total phosphorus level should not be allowed to be too high, as this poses significant risks and involves high costs.
This post was last edited by hesonchang214 on 2014-1-27 at 08:45. The total phosphorus level should generally be kept between 4-10 mg/l. The dosage concentration is determined based on the circulation volume of each system, and it is usually around 60 ppm. This helps to form a fresh film on the surface of the system over time, serving primarily a reparative function. Therefore, in accordance with the requirements set by the Environmental Protection Department, the current trend in this field is to develop phosphorus-free cleaning methods as well as low-phosphorus pre-coating techniques. These approaches will play a crucial role in meeting future environmental standards and addressing the issue of water eutrophication!
This post was last edited by rrstar on 2013-12-19 at 09:12. As a supplementary note, the current trend is toward corrosion and scale inhibitors with low phosphorus content (less than 4 mg/l), or even phosphorus-free ones (below 0.5 mg/l). There is also the trend toward zinc-free products. This is mainly driven by international trends and environmental emission requirements; those who are interested can learn more about it!
The addition level is usually between 20-100 ppm; that’s too high – such a high concentration cannot be used for scale prevention
This post was last edited by rrstar on 2013-12-19 at 16:17. The amount to be added depends on the effective concentration of the chemical and the quality of the water. They are generally selected through static and dynamic tests. Several dozen ppm is completely normal
Under normal conditions, total phosphorus should be kept between 3 and 5 Mg/L; the dosage of chemicals used is related to this level. A level of 50 to 100 Mg/L is still required in some cases. However, low-phosphorus or phosphorus-free formulations are becoming the trend nowadays. Some manufacturers require phosphorus levels to be maintained between 1 and 1.5 Mg/L, while others demand even lower levels, below 0.5 Mg/L. Our company has projects involving the reuse of wastewater for circulating water use, with the total phosphorus limit set at 4–6; the values mentioned above are for reference only!
As a supplementary note, if the goal is merely scale prevention, using a phosphorus-free formula is quite simple. In our company’s facilities, calcium ion levels often remain above 1000 over the long term, and we employ phosphorus-free formulas; the scale prevention effect is excellent, and our customers are very satisfied with us.
It’s not just scale prevention; today’s phosphorus-free solutions also offer decent corrosion inhibition effects. Both in experimental conditions and in actual field applications, they can achieve at least the same results as traditional phosphorus-based solutions.
Generally, it contains phosphorus; the main parameter to be measured is the level of total phosphorus PO4, at 2–4 mg/l. The control parameters include PH, turbidity, FAU Cycle, Cl-, SO42-, Fe2+/Fe3+, total phosphorus PO4, total bacterial count, alkalinity, M-Alkalinity, Ca2+, T-H, residual chlorine, Cu2+, SiO2, and LSI