Thermogravimetric characteristics and evaluation of products during pyrolysis of Camellia oleifera seed residues

To investigate the potential of Camellia oleifera seed residues (COSR) as sources of bioenergy, a systematic evaluation of pyrolysis behavior for COSR was conducted. For pyrolysis kinetics and thermodynamic analysis, Coats-Redfern (CR) model was employed based on thermos-gravimetric (TG) experiments. As heating rates increased, the TG curves and the temperature peaks of the derivative thermo-gravimetric (DTG) curves moved to a higher temperature due to a lag phenomenon. According to kinetic analyses, the activation energy ( E a ) was 95.40–107.97 kJ/mol. With using the obtained E a , thermodynamic parameters were calculated, including pre-exponential factor ( A ), enthalpy change (Δ H ), Gibbs free energy change (Δ G ), and entropy change (Δ S ). After that, based on thermogravimetric analysis (TGA) findings, a scrupulous examination was conducted in a fixed-bed reactor, in which the influences of varying operational conditions, such as pyrolysis temperature, heating rate, reaction time, and particle size, on the COSR pyrolysis process were studied in detail. The results of the fixed-bed pyrolysis experiments observed indicated that N element had been enriched in the particle with finer size, and the optimal operating condition was determined as followed: heating rate of 15 °C/min, particle size within less than 300 μm, reaction time of 0.5 h, and pyrolysis temperature of 500 °C. Under the optimal operating condition, the yields of the liquid, gas, and solid products were discovered to reach 48.15%, 20.12%, and 31.73%, respectively. H 2 , CO, CO 2 , CH 4 , and other gases made up the majority of gas products. By gas chromatography–mass spectrometer (GC–MS), the compositions of pyrolysis oil obtained from COSR pyrolysis at 400, 500 and 600 °C were determined, and it was found that alcohols, ketones, and phenolic compounds accounted for a larger proportion of pyrolysis oil. Pyrolysis oil composition and component distribution were substantially impacted by the pyrolysis temperature.