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Title:	Nickel supported catalysts for green diesel production from palm fatty acid distillate
Authors:	Khairul Basyar Baharudin (P88257)
Supervisor:	Karen Wilson, Prof. Dr.
Keywords:	Universiti Kebangsaan Malaysia -- Dissertation Dissertations, Academic -- Malaysia Heterogeneous catalysis Palm oil
Issue Date:	27-Dec-2019
Description:	The development of nickel supported catalysts has been carried out for green diesel production. The production of green diesel from renewable feedstock involving hydrogen-free deoxygenation (DO) and hydrodeoxygenation (HDO) reaction. DO reaction comprising two main reaction pathways which are decarboxylation (DCX) and decarbonylation (DCN). Catalyst development and design are very crucial to impart the right synergism between catalyst support and active metal is important in order to excite optimum catalytic activity of the synthesized catalyst for a specific reaction system. Catalyst support has an essential role in catalyst development which is to improve support–active metal interaction and later stabilize the active phases by promoting active metal dispersion on the surface, creating an adequate active site and preventing rapid deactivation of the catalyst. In this study, a highly crystalline pure phase of NiO-ZnO (5, 10 and 20 wt.%) and 5 wt.%NiO/Al-SBA-15 catalysts were effectively prepared by wet impregnation method onto the catalyst support of the nanostructured of zinc oxide (ZnO) and ordered mesoporous aluminosilicate (Al-SBA- 15), respectively. ZnO nanoparticles with the raspberry-like structure were synthesized using three different template-free techniques (glycol-solvothermal, low-temperature solvothermal, and coprecipitation methods) for the use as catalyst support. The ZnO nanoparticles from coprecipitation method were the best catalyst support among the three products, owing to their highest purity and crystalline phase, large BET surface area and pore volume, and the finest mesoporous-macroporous structure. Meanwhile, a series of templated mesoporous Al-SBA-15 supports with various Si/Al molar ratios spanning 5–75 were successfully synthesised by a true liquid crystal templating (TLCT) method. The catalytic activity of the NiO-ZnO and 5wt.%NiO/Al-SBA-15 catalyst was studied in the solventless and hydrogen-free DO reaction of palm fatty acid distillate (PFAD) in a semi-batch reactor at 350 °C. The synergistic effect of NiO to both support of ZnO and mesoporous Al-SBA-15 significantly enhanced the deoxygenation of PFAD. The hydrocarbon yield from optimum 20wt.%NiO-ZnO catalyst reached 83.4% with 89.4% selectivity for the diesel range (C11-C17). Meanwhile, the effectiveness 5wt.%NiO/Al-SBA-15(Si/Al=50) catalysts in PFAD deoxygenation proved by the high hydrocarbon yields (86%) and 91% selectivity to the diesel fraction (C11-C17). The large surface area and the presence of high density of Brønsted acid site in the Al-SBA-15 support are the key roles in enhancing DO catalytic reaction by promoting better active metal dispersion and providing an adequate amount of acid site respectively. In order to explore the role of support acidity on catalyst activity and selectivity, 5wt.%Ni/Al- SBA-15 catalyst was prepared by reducing as obtained 5wt%NiO/Al-SBA-15 catalyst. The catalytic activity of the resultant catalysts was studied in the liquid phase hydroprocessing of octanoic acid, chosen as a model compound to assess the impact of acidity on the different reaction pathways. Different hydroprocessing pathways show a strong dependence on support acidity, with selectivity towards C8 alkane production from HDO increases with support Brønsted acidity, whereas competing DCX or DCN to C7 alkanes is independent of support acidity. 5wt% Ni/Al-SBA-15 with a low Si/Al ratio of 5 exhibits the highest Brønsted:Lewis ratio and selectivity towards HDO products. However highly acidic catalysts are prone to deactivation by carbon deposits, and those with intermediate acidity (Si/Al ratio 50) show less deactivation and prolonged activity, reaching octanoic acid conversions of 95%, with 74% selectivity towards n-octane after 5 hours.,'Certification of Masters/Doctorial Thesis' is not available,Ph.D
Pages:	152
Call Number:	QD505 .K483 2019 tesis
Publisher:	UKM, Bangi
Appears in Collections:	Faculty of Science and Technology / Fakulti Sains dan Teknologi

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