Investigation on the kinetic behavior, thermodynamic and volatile products analysis of chili straw waste pyrolysis

Recently pyrolysis has become the sustainable and huge environmental-friendly method for agricultural straw waste (ASW) to evaluate the bioenergy potential. Whereas, the thermal decomposition behavior of chili straw waste (CSW) has not never been explored. This present research systematically studied the bioenergy potential of CSW using three multiple direct characterization tools, including thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectrometer, and Curie-point pyrolyzer-gas chromatograph/mass spectrometer (CPP-GC/MS). Thermal decomposition of CSW has been investigated by TGA under the non-isothermal pyrolysis temperature at four heating rates of 5, 10, 20, and 30 °C min−1, respectively, which can be separated into three processes. Four isoconversional model-free methods such as Kissinger-Akahira-Sunose (KAS), Friedman, Flynn-Wall-Ozawa (FWO), and Starink, were determined the kinetic, ΔH, ΔG, and ΔS of CSW pyrolysis. The average activation energy (Ea) for CSW pyrolysis obtained by Starink, KAS, and FWO methods (195.48, 199.70, and 196.37 kJ mol−1) were lower than that Friedman model (227.15 kJ mol−1). FTIR analysis result showed that CSW was rich in oxygen-containing species and had the great potential for its valuable conversion into renewable bio-fuel. Besides, based on the CPP-GC/MS analysis, oxygenated components including phenols, esters, and acids were major volatile products (VPs) of CSW. [Display omitted] •Pyrolysis behavior of CSW was investigated by TGA and CPP-GC/MS.•Four model-free methods were applied to estimate the pyrolysis kinetic of CSW.•Kinetic and thermodynamics analysis suggested that CSW was suitable for pyrolysis.•The reaction mechanism of CSW pyrolysis followed D3 and F2, respectively.•The flash pyrolysis VPs of 400 °C contained less phenols than that of 500 °C.