Evaluating the bioenergy potential of kitchen wastes fermentation residues through pyrolysis kinetics, thermodynamics and Py-GC/MS analysis technique

Abstract

Pyrolysis non-isothermal kinetics, thermodynamics and products compositional characteristics of kitchen wastes fermentation residues (KWFR) were investigated to explore the bioenergy potential by thermogravimetric analysis and pyrolysis gas chromatography mass spectrometry (Py-GC/MS) methods. The results showed that pyrolysis process can be divided into four common stages. The kinetics results deduced from FWO, KAS and Popescu methods showed that reaction activation energy (E) was 170.56, 168.98 and 172.10 kJ mol⁻¹ and pre-exponential factor (A) was 1.22E + 17, 5.04E + 10 and 1.80E + 15 min⁻¹, respectively, while the optimal mechanism function was G(α) = [1 − (1 − α)^1/3]²(n = 2). The calculated thermodynamic parameters included ΔH (163.77–166.90 kJ mol⁻¹), ΔS (− 62.25–61.28 J mol⁻¹ K⁻¹) and ΔG (145.41–184.02 kJ mol⁻¹). The Py-GC/MS results showed mainly produced nitrogen-containing compounds, acidic alcohol compounds, aldehydes, ketones, esters, benzenes and hydrocarbons. This study highlights KWFR can be considered as an attractive feedstock for bioenergy and bio-based chemicals and meanwhile may help to solve the problem of kitchen wastes digestion tailings.