Combustion of sewage sludge as alternative fuel for cement industry

The combustion of sewage sludge and coal was studied by thermogravimetric analysis. Both differential scanning calorimetric analysis and derivative thermogravimetric profiles showed differences between combustion of sewage sludge and coal, and non-isothermal kinetics analysis method was applied to evaluate the combustion process. Based on Coats-Redfern integral method, some reaction models were tested, the mechanism and kinetics of the combustion reaction were discussed. The results show that the combustion of sewage sludge is mainly in the low temperature stage, meanwhile the ignition temperature and Arrhenius activation energy are lower than that of coal. The combustion of sewage sludge has the advantage over coal in some aspects, thus sewage sludge can partly replace coal used as cement industry fuel.