Novel Catalysts Development for Production of Jet Fuel Range Hydrocarbons from Vegetable Oils
Date
2021-06-03
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
ORCID
0000-0001-8594-7321
Type
Thesis
Degree Level
Doctoral
Abstract
Production of jet fuel range hydrocarbons via processing of oleic acid has proved to be a
viable alternative to the conventional ways of producing jet fuel range hydrocarbons. In this study,
the collaborative influence of Fe on the Cu/SiO2-Al2O3 catalysts of 5–15 wt. % Cu loadings was
established by changing the contents of Fe in the range of 1–5 wt. % on the optimized 13 wt. %Cu
catalyst supported on SiO2-Al2O3. The highest yield (59.5%) and selectivity (73.6%) jet fuel range
hydrocarbons were obtained from the evaluation of the Fe(3)-Cu(13)/SiO2-Al2O3 catalyst at 300
°C and 2.07 MPa H2 pressure, which can be attributed to its desirable textural properties, mild
Bronsted acid sites confirmed pyridine FTIR analysis, high metal dispersion revealed from CO
chemisorption analysis and TPR analysis.
In the second phase of this research work, the collaborative effects of 1 wt.% Ti, 1 wt.%
Zr, and 0.5-2 wt.% Sn on the promising bimetallic catalyst (Fe(3)-Cu(13)/SiO2-Al2O3) were also
established through in depth characterization and evaluation to produce jet fuel range
hydrocarbons via hydroprocessing of oleic acid. Hydroprocessing of oleic acid over 1 wt. % Sn
promoted Fe(3)-Cu(13)/SiO2-Al2O3 catalyst at 320°C, 2.1 MPa H2 pressure and 8 h, resulted in
the highest selectivity (76.8 %) and yield (71.7 %) of jet fuel range hydrocarbons. The promising
performance of the catalyst is attributed to its high metal dispersion (revealed from its smallest
crystallite size of 5.1 nm and its weakest metal-support interaction), desirable textural properties
(revealed from its largest surface area of 571 m2
/g and highest pore volume of 0.65 cm3
/g).
Maximization of selectivity of jet fuel range hydrocarbons and oleic acid conversion with
the best combination of the process parameters involved and evaluation of thermodynamic and
kinetic activation parameters is the focus of phase 3 of this research work. Reduced quadratic jet
fuel range hydrocarbons selectivity model and reduced cubic oleic acid conversion model of high
significance levels and high correlation coefficient were developed. Reaction temperature of 339.5
oC, 6.2 wt.% catalyst concentration, 1.6 MPa H2 pressure and 8.0 h reaction time were the optimum
process parameters that can maximize selectivity of jet fuel range hydrocarbons and oleic acid
conversion at 82.2% and 98.2 %, respectively. This process was found to be endothermic,
irreversible and non-spontaneous with 45.8kJ/mol activation enthalpy of reaction, -0.25kJ/mol
entropy of reaction and the reaction’s Gibb’s free energy of 198.8kJ/mol at 340 oC. The minimum
energy required for the reaction to take place was evaluated to be 50.7kJ/mol.
iv
Production of aviation biofuel that will be competitive with the conventional jet fuel
derived from crude oil in terms of its cost effectiveness has been the subject of research in recent
years. In the phase 4 of this research work, technoeconomic analysis of greenseed canola derived
jet fuel range hydrocarbons were carried out using a SuperPro design software. 79200 MT/year of
oleic acid (model compound of greenseed canola oil) was hydroprocessed with 1.6 MPa of
hydrogen over a 1 wt. % Sn promoted trimetallic catalyst to produce 59345 MT/year jet fuel range
hydrocarbons of 99.5 wt. % purity. Economic evaluation of the production process revealed net
annual profit of 1.25 million dollars, respectively, with 38.46 % return on investment and 2.6 years
payback time.
In conclusion, a novel 1 wt. % Sn promoted on Fe(3)-Cu(13)/SiO2-Al2O3 catalyst was
established to be effective and profitable for production of jet fuel range hydrocarbons after
optimization of catalysts of different supports, loadings of Sn, Fe and Cu, process parameters and
economic evaluation.
Description
Keywords
Jet fuel, Hydroprocessing, Oleic acid, Sn-promoted catalyst, metal–support interaction, Optimization, Kinetics
Citation
Degree
Doctor of Philosophy (Ph.D.)
Department
Chemical and Biological Engineering
Program
Chemical Engineering