XINLI BOILER

How does these annoying scales form in the biomass boiler?

14 Oct, 2021

　　How did these annoying scales form?

　　1. Decomposition by heat

　　After the water with temporary hardness enters the boiler, during the heating process, some calcium and magnesium salts are heated and decomposed, and they change from water-soluble substances to hardly water-soluble substances, which adhere to the boiler metal surface and form scale, calcium and magnesium. The salt is broken down as follows:

　　Ca(HC03)2 →CaC03 ↓ +H2O+C02↑Mg(HCO)2→MgC03+H2O+C02↑MgC03+H2O → Mg(OH)2↓+c02↑

　　2. Some salts are greater than their solubility. Due to the continuous evaporation and concentration of pot water, the content of dissolved salts in the water continues to increase. When some salts reach supersaturation, the salts will precipitate solid phases on the evaporation surface and form Scale.

　　3. Decrease in solubility

　　As the temperature of the pot water increases, the solubility of certain salts in the pot water decreases, such as CaS04 and CaSi03.

　　4. Mutual reactions

　　After the water with relatively high original solubility in the feed water reacts with other salts and alkalis in the boiler water, compounds that are insoluble in water are formed, which causes the formation of scale. Some salts and bases react with each other as follows:

　　Ca(HC03)2+2NaOH=CaC03 ↓ +N4C03+H20CaCl2+Na2C03=CaC03↓+2NaCl5. Slag conversion:

　　When there is too much water slag in the pot, and it is sticky, such as Mg (OH)2 and Mg3(P04)2, etc., if the sewage is not discharged in time, it is easy to turn the sludge into scale.

　　In the above, we have analyzed the hazards and causes of biomass boiler scale. How can we remove these scales? In fact, we only need to use relevant boiler descaling agents to treat scale.