Characterization of cassia fistula seed and shell co-pyrolysis yield optimization by response surface methodology and compositional analysis

Abstract

The primary objective of this study was to enhance the bio-oil yield from the seed, shell, and blend of Cassia fistula (CF) through the application of response surface methodology (RSM). The study focused on analysing the product composition, qualities and optimizing the process by altering the heating temperature, the heating rate, and CF seed to CF shell blend ratio. The physicochemical characteristics of biomass samples were evaluated through Fourier Transform Infrared, proximate analysis, elemental analysis, X-ray diffraction, higher heating value, fuel reactivity, thermogravimetric analysis, CHO index, etc. Analysis of variance established that the temperature during co-pyrolysis of the CF seed and shell was the most critical factor in determining the bio-oil yield. The optimal bio-oil yield, gas yield, and char yield were obtained at a heating temperature of 450 °C, a heating rate of 10 °C/min, and a blend ratio of 75%. A statistical model was constructed to examine the parameters identified through analysis of variance as having a substantial impact on the experimental results. This study provides insights into RSM approaches that lead to a more practical approach to process modelling. Gas chromatography-mass spectrometry revealed that the bio-oil was primarily composed of hydrocarbons, followed by ketones and phenolic compounds. The bio-oil analysed exhibited a carbon chain range of C2-C12.