A comparative study on combustion characteristics and kinetic behaviors in the co-combustion process of sewage sludge with oily sludge/cow manure

The characteristics of combustion and related parameters of sewage sludge (SS), oily sludge (OS) and cow manure (CM), as well as their co-combustion characteristics were studied by thermogravimetric analysis (TGA). The comprehensive combustion characteristic index (S) of SS was improved due to the addition of OS. The S of the 20 % SS and 80 % OS mixture was 13 times that of SS, and the addition of OS also improved the combustion stability index (R_w). The addition of CM to SS reduced S, the S of the 20 % SS and 80 % CM mixture decreased by 60 % compared to SS, but the combustion stability was improved. Compared with mono combustion, the ignition points (T_i) and burnout temperature (T_h) of co-combustion had different degrees of change. Different proportions of the mixture had a synergistic effect at each combustion stages. The SS and CM mixtures exhibited pronounced interactive effects, with their role shifting between promotion and inhibition at the different temperature stages. The addition of OS and CM affected the activation energy (E) of the entire process, but the extent of the influence varied at the different combustion stages. This study provides theoretical support for the large-scale co-combustion of SS with OS or CM, and offers valuable fundamental data.