Comprehensive characterization of thermal decomposition of sewage sludge by TG–MS

•New quasi-quantitative approach to analysis the TG–MS data for pyrolysis of sewage sludge was proposed.•The method allows to determine the evolution rate of gas and total liquid products released.•The proposed method can be also used for studying any gas–solid reaction where gaseous components are evolved.

Based on results of sewage sludge pyrolysis performed in a thermo-balance coupled with mass spectrometer (TG-MS) and elemental analysis of the substrate and solid residue a new integrated approach for quantification of yields and composition of the products was proposed. The TG-MS measurement enables to obtain the yield of oil and tars. Additionally employing the elemental analysis an approximate composition of liquid product can be also calculated. To obtain more detailed information on the mechanism of pyrolysis deconvolutions of DTG curve and profiles of evolved product into eight groups of reaction occurring at different temperature regions were performed. The proposed method can be also used for studying gas–solid reactions where CO, CO2, H2 and H2O are the main gaseous components (e.g. catalyst reduction, water–gas shift reaction etc.).