Utilization of an Organic Calcium Compound to Reduce SO₂ and NO Emissions from Sewage Sludge Combustion

To remove gas pollutant emissions from sewage sludge combustion, modified calcium magnesium acetate (MCMA) was used as an organic calcium compound (OCC) to blend with sludge. The main objective of this study was to determine the pollutant emission characteristics of sewage sludge and fuel blended with MCMA during combustion in a tube furnace. The effects of operating parameters on the mean SO₂ and NO emissions and the reduction ratios of SO₂ and NO were investigated. The results showed that MCMA simultaneously captured 69.9% of SO₂ and 31.3% of NO at a temperature of 800 °C and a Ca/S molar ratio of 2.0. Furthermore, the Ca/S ratio and reaction temperature significantly impacted the mean SO₂ emission and SO₂ reduction ratio. The SO₂ reduction ratio increased with increases of the Ca/S ratio and temperature. However, SO₂ emission decreased with increasing Ca/S ratio but increased with increasing reaction temperature. In addition to the main effects corresponding to single factors, the interaction effect of air flow rate and Ca/S ratio was a dominant factor that affected the mean NO emission and NO reduction ratio