MODELLING AND OPTIMIZATION OF PYROLYSIS OPERATING PARAMETERS FOR ENERGY GENERATION

ONOKWAI,, ANTHONY OGOCHUKWU (2022) MODELLING AND OPTIMIZATION OF PYROLYSIS OPERATING PARAMETERS FOR ENERGY GENERATION. ["eprint_fieldopt_thesis_type_phd" not defined] thesis, Landmark University, Omu Aran, Kwara State.

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Abstract

The increasing call for clean and sustainable energy has been at the forefront of global efforts toward the drive for greener economies and sustainable developments amid other parameters. Problems are being faced in enhancing the quantity and quality of pyrolysis yields due to poor characterization of biomass and improper parameters mix during experimentation run. This study utilized response surface methodology (RSM) to model and optimize operating parameters for pyrolysis. Temperature, reaction time, heating rate, nitrogen, and particle size were chosen to maximize quantity, energy, and exergy efficiency of bio-oil, biochar, and non-condensable gases (NCG) of palm kernel shell (PKS), sugarcane bagasse (SCB), and shea butter wood (SBW) based on the outcome of experimental runs. A quadratic model was found fit for the optimization and elucidates the non-linear nature of the model response. The optimum bio-oil, biochar, and NCG are 47.5, 40.7, and 35.5 wt% for palm kernel shells; 48.4, 40.5, and 33.5 wt% for sugarcane bagasse; and 46.8, 42.5, and 34.2 wt% for shea butter wood respectively. Also, the optimum energy and exergy efficiency for bio-oil, biochar, and NCG are 53.3 and 48.2, 28.3 and 23.7, as well as 15 and 11.6% respectively. The probability value<0.05, high Fischer-value (F-value) for bio-oil (303.95), biochar (877.64) and NCG (487.74) as well as coefficients of determination (R2) of 0.98562, 0.9956 and 0.9921 for bio-oil, biochar and NCG respectively make the developed mathematical model suitable, reliable, responsive, and predicted the experimental data. The actual and predicted values for quantity, energy, and exergy efficiency of products of pyrolysis clearly showed that the experimental data are in good agreement with the predicted values. The Fourier Transform-Infrared Spectroscopy and Gas Chromatography-Mass Spectrometry (GCMS) analysis of bio-oils and biochar depicted relatively high percentages of alcohol, oleic acid, aromatic and aliphatic hydrocarbons, phenol, aldehyde, and ketone. The Scanning Electron Microscope/Electron Dispersive X-Rays Spectroscopy (SEM/EDX) results for the biochar showed whitish deposits, cleaves, heterogeneous pores, cloudy and cloggy formations depicting inorganic materials, rapid volatile emission and efflorescence during pyrolysis processes at higher temperature. This study has successfully shown that modeling more than three pyrolysis operating parameters using a Response Surface Methodology (RSM) optimizes the pyrolysis yields as well as its energy and exergy efficiency. The biochar and bio-oil samples can be utilized as biofuel for industry applications and additives for waste management strategies, petrochemical industry, sorbent, and soil enhancers.

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