Pyrolysis of Telfairia occidentalis Hook.f. pod: process optimization and bio-oil characterization

Agricultural residues represent an underutilized renewable resource for sustainable energy production. This study investigates the pyrolytic conversion of Telfairia occidentalis pod (TOP), an abundant agro‑waste in Nigeria, into bio‑oil using a batch muffle furnace reactor. The effects of temperature (400–600 °C), particle size (150–250 µm), and residence time (30–90 min) on bio‑oil yield were systematically examined using a full factorial experimental design. Response Surface Methodology (RSM) was employed to optimize operating conditions for maximum bio‑oil yield. The physicochemical properties of the bio‑oil were evaluated, and its chemical composition was characterized using Gas Chromatography–Mass Spectrometry (GC‑MS) and Fourier Transform Infrared Spectroscopy (FTIR). The maximum bio‑oil yield of 41 wt. % was obtained at 500 °C, 150 µm particle size, and 30 min residence time. GC‑MS analysis revealed the presence of phenolics, organic acids, furans, aldehydes, ketones, and aliphatic hydrocarbons, while FTIR confirmed dominant oxygenated functional groups. The results demonstrate that Telfairia occidentalis pod is a promising lignocellulosic feedstock for bio‑oil production and supports its valorization within waste‑to‑energy and circular economy frameworks.