Co-combustion behavior of dyeing sludge and rice husk by using TG-MS: Thermal conversion, gas evolution, and kinetic analyses

Co-combustion of dyeing sludge (DS) and rice husk (RH) is a promising energy-from-waste method. The aim of this work was to investigate and quantify the effect of RH additive on combustion performance, gas evolution (especially gaseous pollutants) and kinetics during DS combustion by thermogravimetry-mass spectrometry method. Results revealed that the introduction of RH improved the combustibility, burnout performance and combustion stability of DS. Optimal RH addition (10% RH) reduced the emission of gaseous pollutants (NH₃, NO₂, COS, SO₂ and CS₂). The interaction between DS and RH inhibited the devolatilization reaction and emission of gaseous sulfur substances, and it also restrained NO₂ emission under optimal RH additive amount. A four-interval kinetic model (D₁ → F₃ → D₁ → F₃) was established to describe the co-combustion process (R² greater than 0.9999). RH addition, especially at high doses, led to an increase in activation energy relative to DS.