Thermal conversion behaviors, kinetics, and thermodynamics of wastewater sludge via thermogravimetric analysis, and emission characteristics from a large-scale incinerator

This paper concerned the thermal conversion characteristics, kinetics, thermodynamics, and incineration operation parameters and gas emissions of petrochemical wastewater (PW) and its sludge (PWS). The combustion properties of PWS were evaluated via thermogravimetric analysis, and the results showed that the combustion process of PWS had four stages, and the combustion pathway was typical “thermal degradation with char formation + char combustion”. With heating rates increasing, thermal curves shifted toward lower temperatures, and the ignition, burnout, and comprehensive combustibility improved significantly. The kinetic parameters were determined by Coats–Redfern approach, and the results confirmed the existence of kinetic compensation effect. The thermodynamic parameters (ΔH, ΔG, ΔS) from PWS combustion at maximum degradation rate temperatures were estimated by the activated complex theory. To make the research practical, operation parameters and gas emissions from a petrochemical wastewater incinerator were tested. The results showed that, except HCl, and CO at 4.50 t h–1 PW injection, the gas pollutants in the flue gas after the PW incineration did not exceed the discharge limits in China. The parameters of combustion efficiency of the incineration plant at different PW injections were very high, and met the requirement in GB 18484-2001.