Where does the power plant add phosphate?

According to today's headline official data, the power plant adds phosphate to the boiler drum. Although the water supplied to the drum in the power plant is deionized water, there is still a small amount of hardness in the water. In order to prevent calcium ions from scaling, phosphate scale inhibitors are often added. At a certain PH value, Ca2+ and PO43- will generate basic calcium phosphate. Alkaline calcium phosphate does not generate scale in the boiler, but exists in the form of water slag, which can be discharged out of the furnace with boiler water.

Dosing is to prevent trisodium phosphate from adhering to the pipe wall and precipitating sodium hydroxide. It is often necessary to control the dosage of phosphate. The instrument is analyzed and controlled by phosphorus meter, and the low dose and high dose are stopped. The control range of PO43- concentration in boiler water of large chemical plants in China is generally 2 ~ 10 ppm.