Total phosphorus control issues in circulating water
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Total phosphorus control issues in circulating water； For example, 3.5~5.5, is it better to control close to 3.5 or 5.5?
Total phosphorus is an indicator of the dosage of corrosion and scale inhibitors added to circulating water. Our company's control range is 2 to 8 mg/l. In fact, what the poster proposed is within the control range. If it is too high, it will cause waste. I think as long as the corrosion and scale inhibitors are added properly, they can play their role.
It is said that the optimal value of total phosphorus in circulating water is about 2.2! But in fact, the deviation is often very large, because the specific conditions of various circulating water are different. Of course, you can adjust it yourself using 2.2 as the base value. In addition, there is a premise that it is best to keep the pH value in the range of 6.5 to 8.5 and take into account that the total phosphorus in the effluent cannot exceed the standard.
It is recommended to use phosphorus-free corrosion and scale inhibitors PESA and PASP, or appropriately compound them with HEDP.
Our company's water treatment chemicals are outsourced, and the company requires it to be controlled at 3.5~5.5mg/l.
The current industrial water discharge standards require total phosphorus to be less than 1 mg/l. How can you have such a high total phosphorus? Circulating water must be discharged. The chemicals you use are too old. Nowadays, inorganic phosphorus corrosion and scale inhibitors are no longer used, but organic phosphorus corrosion and scale inhibitors are used. The total phosphorus in good circulating water can achieve the effect of corrosion and scale inhibition when it is 0.5mg/l! For example, HEDP, HPAM, PESA, HPA, ATMP, etc. are their copolymer compound systems!
The total phosphorus size control also depends on the concentration ratio. Taking 6000 cubic meters/hour as column 1. When the concentration ratio of the circulating water is greater than 3, the total phosphorus content of the system is controlled to 4~6mg/l. 2. When the concentration ratio of circulating water is 2~3, the total phosphorus content of the system is controlled to 6~8mg/l. 3. When the concentration ratio of circulating water is less than 2, the total phosphorus content of the system is controlled to 8~14mg/l.
From the control point of view, if the system is required to have no problems, of course the upper limit should be used as the control indicator, such as nearly 5, and there are no restrictions on environmental protection indicators, and it is outsourcing. The higher the organophosphate, the better the effect. If the control cost is used as the indicator, it should be close to 3.5, such as 3.7. But judging from my experience in circulating water, in addition to economic benefits, the safety of the system is also required. Generally, the average value is slightly above the range, such as 3.5-5.5. It is best to control the total phosphorus around 4.5.
As long as it is within that range, since it is outsourcing, we should strictly control it according to the indicators given by others to avoid problems. The control should be as stable as possible and not fluctuate too much.
Xiaobai come and learn* , the total phosphorus control index should be related to process production. We are coal chemical industry circulating water, and the control index is 0.9-1.5