Preparation of N-Doped Porous Catalyst derived from Petroleum Coke using Ball Milling for the Oxidative Desulfurization of Fuel
AuthorAhmed, Ahmed Magdy Abdelaziz
Committee MemberJeje, Ayodeji
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AbstractA catalyst for oxidative desulfurization of hydrocarbon fuels is derived from petroleum coke. Petroleum coke (petcoke) is a low-value, readily available (with >80 wt% carbon) waste produced as a by-product at oil refineries and upgrading facilities. Between 11 and 20 % of the annual production of petcoke in Alberta is used as fuel blends in refineries. The surplus millions of tonnes are stored in the open, constituting an environmental hazard due to wind-blown dust from piles. More than 80% of the world's production is low-grade with high sulfur content (>5 wt% sulfur) and not suitable for combustion as hazardous SOx gases are generated. Petcoke is a non-porous material that can be modified physicochemically. Compared to conventional alumina-based catalysts, petcoke is less sensitive to nitrogen compounds present in crude oil and more resistant to coke deposition, which make it a good choice for catalysis applications. High energy ball milling is an environmentally friendly technology compared to other conventional techniques used to modify the properties of several carbon materials. The present work used high-energy ball milling to convert low-value, abundant petcoke to an added-value nitrogen-doped porous heterogeneous catalyst, which will be tested for the oxidative desulfurization of fuel. The preparation procedure included dry ball milling of petcoke with urea as the nitrogen precursor followed by pyrolysis in nitrogen to obtain the nitrogen-doped catalyst. The effect of ball milling time (5-1440 min), pyrolysis temperature (600-1000 ℃), and urea to petcoke mass ratio (1:1 to 5:1) on the physical properties and chemical composition of the product material was studied. Increasing the ball milling time, led to an increase in surface area and pore volume and higher nitrogen doping, while increasing the pyrolysis temperature >600 ℃ resulted in a lower surface area and pore volume. Controlling these conditions resulted in increases in the surface area from 1 to 166 m2/g, pore volumes from 0.004 to 0.38 cm3/g, and nitrogen contents from 1.4 to 7 wt%. Nitrogen doping of petcoke was achieved with ⁓98% yield and the development of mesoporosity.
CitationAhmed, A. M. A. (2022). Preparation of N-Doped Porous Catalyst derived from Petroleum Coke using Ball Milling for the Oxidative Desulfurization of Fuel (Unpublished master's thesis). University of Calgary, Calgary, AB.
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