Different pyrolysis kinetics and product distribution of municipal and livestock manure sewage sludge

Thermogravimetric analysis and pyrolyzer-gas chromatography/mass spectrometry measurements were taken to examine the kinetic behavior and product distribution on the thermal and catalytic pyrolysis of different types of sewage sludge. Compared to livestock manure sewage sludge (LMSS), municipal sewage sludge (MSS) had larger ash (30.3%) and lower fixed carbon (7.9%) contents. The peak intensities for the 1st decomposition region (200–380 °C) on the derivative thermogravimetric curve of MSS were higher than those of LMSS. In contrast, the peak height in the 2nd temperature region (>380 °C) of MSS was lower than that of LMSS. The activation energy for the pyrolysis of MSS (Avg. 186.5 kJ/mol) was lower than that of LMSS (Avg. 263.4 kJ/mol) over the entire conversion range. MSS produced larger amounts of fatty acids and cholesterol than LMSS. The in-situ catalytic pyrolysis of MSS over HBeta using a pyrolyzer-gas chromatography/mass spectrometry also produced larger amounts of aromatic hydrocarbons than LMSS, suggesting that its better feedstock properties strongly influence the final product oil quality. [Display omitted] •Pyrolysis of different kinds of sewage sludge was investigated.•Municipal sewage sludge had lower activation energy during pyrolysis.•Larger amount of toluene and oleic acid was produced from municipal sewage sludge.•Catalytic pyrolysis of municipal sewage sludge over HBeta produced aromatics. In terms of low activation energy and production of a lot of valuable chemicals, municipal sewage sludge can be a better feedstock than livestock manure sewage sludge.