Relationship Between SO2 Emissions and Precipitator Dust Composition in Recovery Boilers, 2000 Engineering Conference Proceedings

Honghi Tran, Wm. James Frederick, Jr., Kristiina Iisa, Alarick Tavares, and Roberto Villarroel--The relationship between SO2 emissions and precipitator dust composition and its implications on tube fouling were examined based on data obtained from a number of field studies conducted at kraft mills. The results show that while SO2 emissions and the carbonate content in the precipitator dust are strongly related to each other, there is no or little correlation between SO2 emissions and chloride and potassium contents. The results also imply that sulphation reactions involving alkali hydroxide and chloride vapours, SO2, O2 and H2O occur mainly in the oxidizing region before the superheater entrance. Once carbonate and chloride fume particles have been formed in the boiler, they will be unlikely to be sulphated in-flight. As long as the dust contains some carbonate, it will unlikely contain liquid acidic sulphates and thus will not be sticky.