Effects of Metal Oxides during Pyrolysis Sludge by Kinetic Analysis

Abstract

On the basis of proximate analysis, element analysis and calorific value that carried out on the sewage sludge, thermogravimetric analyzer (TGA) was conducted on the research of sewage sludge pyrolysis. The loss of sludge under different heating rates was comparative analyzed. And we calculated the activation energy by using Ozawa method, Satava method was also used to infer the most probable mechanism function and kinetic parameters. the result shows that sludge pyrolysis process can be divided into three parts as 200-450°C,450-600°C and above 600°C, the Reaction mechanism functions for the pre main two parts were G(α)=(1-α)-1 and G(α)=[-ln(1-α)]2/3respectively. Its proved that Al2O3,MgO probably inhibited the decomposition while Fe2O3,CaO,ZnO promoted the degradation of organic matters under 200-450°C. CaO and Fe2O3 showed advantage while MgO, Al2O3, ZnO turned to be disadvantagble when temperature arised to 450-600°C. At the end of pyrolysis, the advantage effects order on pyrolysis : Al2O3> Fe2O3>MgO >ZnO>CaO.