Three months after replacing the denitration catalyst in a high-purity shaft kiln,the problem of excessive NOx emissions arises.This paper analyses the reasons through sampling analysis and on-site testing.The results show that the newly replaced denitration catalyst works well under the flue gas conditions in the high-purity magnesia shaft kiln,without deactivation due to catalyst damage.The direct cause of excessive NOx emissions is the gradual corrosion and perforation of GGH heat exchanger due to the slow accumulation of ammonium bisulfate,which ultimately leads to the leakage of pre-denitration flue gas into the post-denitration flue gas.The denitration process of"bag filter+heat exchange and temperature rise through GGH+temperature rise through HBS+medium-temperature SCR denitration+temperature drop through GGH"generally conforms to the emission characteristics of flue gas pollutants in high-purity magnesia shaft kilns,and the chemical life of the catalyst can reach about three years.
维普
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