Causes of water pollution
1) leakage or leakage of condenser
The main reason for the condensation of water pollution is that the cooling water leaks from the imprecise parts of the condenser to the condensation water.
Imprecise part is usually used in condenser in the condenser inner tube bundle and tube plate joint, due to changes in the plant can make the condenser inside produce mechanical stress, even if the condenser manufacture and installation quality is better, still may occur in using circulating cooling water leakage or leakage phenomenon.
In the cooling water, there are more suspensions, colloids and salts, which must affect the water quality.
2) pollution of metal corrosion products
The pipe and equipment of the condensate system can be corroded for some reason, so there are often metal corrosion products in the condensed water.
The main ones are iron and copper oxide (my company's thermal system equipment has basically no copper material).
The form of iron mainly consists of Fe2O3 and Fe3O4, which are suspended and colloidal, and also have various ions of iron.
Amount of corrosion products in the condensate is associated with the operation condition of unit, unit in the initial condensate water corrosion products is more, the other under the condition of load instability could increase content of impurities.
3) boiler resupply water into a small amount of impurities
Chemical water treatment mixed bed water is the boiler recharge water, usually from the condenser to the thermal system.
Due to the strict control of the mixed bed and water in operation, the content of the resupply water is very small, and its water quality requirements: DD is less than 0.2mu s/cm, and SiO2 is not equal to 20 mu g/L.
If the mixing bed is not qualified, it may cause pollution to the condensate.
Due to several reasons above, the condensate, more or less certain pollution for supercritical parameters of the unit, due to the demand for feed water quality is very high, so the need for deeper degree of purification of the frozen water, namely the condensate polishing processing.