Abstract:
Cassava peels (CP) constitute an important source of energy in the tropical region, are one of
the most abundant agricultural residues, and have a high biofuel production potential. This
thesis work investigates the effect of pyrolysis parameters on the bio-oil production yield from
CP. The two principal objectives were to perform a comparative assessment of empirical
methods of fast determination of lignocellulosic composition and predict numerically the
pyrolysis byproduct yield using the detailed kinetic model of biomass pyrolysis.
The results show that TGA data can be used for accurate determination of the lignocellulosic
composition of biomass, the error between results from the chemical method data and TGA PKM method (±7%) lies in the range of error obtained from experimental chemical methods
(±10%). Additionally, the empirical method of lignocellulosic composition based on elemental
composition does not include all biomass samples. Therefore TGA-PKM method is an
interesting option to have a good estimation of lignocellulosic fractions content. The quality of
the fit between the DTG curves from the experiment and from the model for CP gave an R2 =
0.9765.
The kinetics parameters were obtained by isoconversional methods based on thermal
devolatilization behavior for four different heating rates: 5K/min, 15K/min 20K/min, and
30K/min. The mean value of activation energy using the KAS, FWO, and Friedman method
was 224.87kJ/mol, 234.3kJ/mol, and 347.87kJ/mol respectively. Finally, the result from the
investigation of pyrolysis conditions on bio-oil yield showed that the maximum bio-oil yield is
obtained for the heating rate ranged between 80K/min to 100K/min. tacking into account the
secondary reaction of tar, the vapor residence time affect negatively the bio-oil yield. An
optimum pyrolysis temperature for maximum bio-oil yield is around 475°C. CP pyrolysis is not
significantly affected by the particle size when the latter is less than 0.5mm since the
temperature gradient between the surface and the center of the particle is less than 1°C.
