I have two chain boilers here, and the smoke from one of them is blue. Does anyone among you know what could be causing this?
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Our company has two chain boilers; one of them emits blue-colored flue gas. Denitration is carried out using SNCR, desulfurization is done via the double-alkali method, and bag filtering is used for dust removal. We tried turning off the denitration and desulfurization systems, but the flue gas still remained blue. Both boilers use the same type of coal. Does anyone know what could be the reason?
It might be caused by incomplete combustion; (excessive air flow results in too high exhaust temperatures. ）
Okay, then I’ll reduce the air volume and see. Thank you. Are there any other reasons?
It certainly isn’t caused by an excessive air supply; if blue smoke is produced due to incomplete combustion, it should be because the air supply is insufficient. It is recommended to compare the operating parameters of the two furnaces (carefully examining the differences), paying particular attention to the flue gas temperature, the volume of air supplied (and in the absence of such data, the current drawn by the fans), and the oxygen content in the exhaust gases (a low level indicates incomplete combustion).
Blue smoke is sulfur trioxide; therefore, boilers that emit blue smoke have extremely high levels of sulfur trioxide emissions, and there is a problem with their desulfurization systems. The person asking the question should check it themselves
The air supply volume is too low; increase it. It is clearly due to incomplete combustion, which results in the production of large amounts of CO. CO is colorless, but when it is emitted at high temperatures, some of it gets oxidized, resulting in a blue flame during combustion.