Effect of anaerobic digestion on sequential pyrolysis kinetics of organic solid wastes using thermogravimetric analysis and distributed activation energy model

•TGA-DAEM was used to explore effect of anaerobic digestion on sequential pyrolysis.•Anaerobic digestion causes a decrease in the weight loss at the range of 180-550 °C.•Organic matter at peak temperature of 274-327 °C enriched after anaerobic digestion.•Anaerobic digestion had discriminative effects on pyrolysis kinetics of the OSW.•Different organic composition between the OSW might be an important reason.

Thermogravimetric analysis, Gaussian-fit-peak model (GFPM), and distributed activation energy model (DAEM) were firstly used to explore the effect of anaerobic digestion on sequential pyrolysis kinetic of four organic solid wastes (OSW). Results showed that the OSW weight loss mainly occurred in the second pyrolysis stage relating to organic matter decomposition. Compared with raw substrate, the weight loss of corresponding digestate was lower in the range of 180-550 °C, but was higher in 550-900 °C. GFPM analysis revealed that organic components volatized at peak temperatures of 188-263, 373-401 and 420-462 °C had a faster degradation rate than those at 274-327 °C during anaerobic digestion. DAEM analysis showed that anaerobic digestion had discrepant effects on activation energy for four OSW pyrolysis, possibly because of their different organic composition. It requires further investigation for the special organic matter, i.e., protein-like and carbohydrate-like groups, to confirm the assumption.

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