Influence of catalysts on co-combustion of sewage sludge and water hyacinth blends as determined by TG-MS analysis.

Effects of the three metal carbonates (K2 CO3 , Na2 CO3 , and MgCO3 ) were quantified on catalytic co-combustion of the sewage sludge and water hyacinth (SW) blend using a thermogravimetric-mass spectrometric (TG-MS) analysis and kinetics modeling. The main dominating steps of the catalysts were the organic volatile matter release and combustion stage. Weighted mean values of activation energy (Em ) were estimated at 181.18KJ·mol-1 , 199.76KJ·mol-1 , 138.76KJ·mol-1 , and 177.88KJ·mol-1 for SW, SW+5% K2 CO3 , SW+5% Na2 CO3 , and SW+5% MgCO3 , respectively. The lowest Em occurred with SW+5% Na2 CO3 . Overall, catalyst effect on co-combustion appeared to be negligible as indicated by Gibbs free energy (ΔG). The normalized intensities of SW+MgCO3 were strongest. The addition of Na2 CO3 and MgCO3 to SW increased flue gases emissions (CO2 , NO2 , SO2 , HCN, and NH3 ) of SW, whereas the addition of K2 CO3 to SW reduced flue gases emissions from the entire combustion process.