Heavy oil derived from oil sands is becoming an important resource of energy and transportation fuels due to the depletion of conventional oil resources. However, bitumen and heavy oils have a low hydrogen/carbon ratio and contain a large percentage of sulfur and nitrogen heterocyclic compounds. At the level of deep desulfurization, aromatic poly-nuclear molecules, especially nitrogen-containing heterocyclic compounds, exhibit strong inhibitive effect on hydrodesulfurization (HDS) due to competitive adsorption on catalytically active sites with sulfur-containing molecules. Therefore, it is necessary to study the HDS of refractory sulfur-containing compounds and also the effect of nitrogen-containing species on the deep HDS for achieving the ultra low sulfur specifications for transportation fuels. Additionally, the cost of H2 increased in recent years and a bitumen emulsion upgrading technique using an alternative in-situ H2 generated via the water gas shift (WGS) reaction during the hydro-treating was developed in our group.

The development of efficient catalysts for hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) processes is an essential and urgent research field. During oil refinement the removal of sulfur and nitrogen compounds from petroleum feedstock is crucial, as the emission of sulfur and nitrogen oxides into the atmosphere causes severe environmental problems. In light of the industrial process for hydrocarbons, HDS is indispensable as it eliminates the poisoning of catalysts during hydrotreatment and hydrocracking. In order to develop new catalysts, the mechanism of these reactions as well as the structures and functions of the catalysts need to be elucidated. This book provides an up-to-date and deep insight, which spans kinetic studies, catalytic cycles, structures and properties of catalysts to process engineering. Therefore every chemist and engineer working in this important research field will welcome this valuable source of information.

In situ decomposition of ammonium and tetrabutylammonium thiomolybdate (ATM and TBATM) were used to synthesize unsupported MoS[subscript 2] catalysts, the in situ activation consisted of decomposing the thiomolybdate precursors in the presence of hydrocarbon solvent under H[subscript 2] pressure at 350degrees Celsius during the hydrodesulfurization (HDS) of dibenzothiophene (DBT) or 4,6-dimethydibenzothiophene (4,6-DMDBT) as sulfur model compounds. In situ generated MOS[subscript 2] catalysts were characterized by XRD, BET, EDX and SEM. Parameters affecting the HDS reaction were investigated: hydrogen pressure, reaction time, amount of precursor, types of precursor, cobalt and nickel promoters, and water addition. Inhibition of pyridine was also examined. The results showed that, cobalt and nickel addition enhanced HDS activity of both in situ generated MoS[subscript 2] catalysts from ATM and TBATM precursors. The use of ATM precursor with added water for in situ generation of MoS[subscript 2] catalyst can lead to 100% conversion of HDS of 4,6-DMDBT under 30 atm H[subscript 2] pressure at 350degrees celsius. Model reaction suggested that water addition led to a high surface area, highly active MoS[subscript 2] catalyst. The optimal mole ratio of H[subscript 2]O/ATM = 1200 performed the highest surface area (559 m[superscript 2]/g). In addition, the catalysts could reduce the sulfur contents of straight run gas oil (SRGO) from 6100 ppm to 3250 ppm and from 310 ppm to 100 ppm in light cycle oil (LCO).

This book is part of a two-volume work that offers a unique blend of information on realistic evaluations of catalyst-based synthesis processes using green chemistry principles and the environmental sustainability applications of such processes for biomass conversion, refining, and petrochemical production. The volumes provide a comprehensive resource of state-of-the-art technologies and green chemistry methodologies from researchers, academics, and chemical and manufacturing industrial scientists. The work will be of interest to professors, researchers, and practitioners in clean energy catalysis, green chemistry, chemical engineering and manufacturing, and environmental sustainability. This volume focuses on catalyst synthesis and green chemistry applications for petrochemical and refining processes. While most books on the subject focus on catalyst use for conventional crude, fuel-oriented refineries, this book emphasizes recent transitions to petrochemical refineries with the goal of evaluating how green chemistry applications can produce clean energy through petrochemical industrial means. The majority of the chapters are contributed by industrial researchers and technicians and address various petrochemical processes, including hydrotreating, hydrocracking, flue gas treatment and isomerization catalysts.

"Problems associated with hydrotreating of heavy and extra-heavy crude oils in conventional fixed-bed reactors have led to the design of more innovative reactors such as slurry reactors. Dispersed fine catalysts are commonly used in slurry reactors. However, separation of the fine particles with sizes in micrometers or nanometers from the liquid phase represents a challenge. In this work, novel magnetically recyclable catalysts are designed to address this issue. Two different magnetic core materials, Fe3O4 and Fe3S4, were studied. Core-and-shell composite catalysts MoS2/Fe3O4 and MoS2/Fe3S4 were designed. Both catalysts showed high activity in the hydrodesulfurization (HDS) of dibenzothiophene (DBT). Former one showed high affinity towards the direct desulfurization (DDS) pathway while the later one presented a balanced selectivity between DDS and hydrogenation (HYD) pathways. This provides the refineries an option to adjust the hydrotreating process based on their needs using each of the catalysts or a combination of both. Catalyst MoS2/Fe3S4 was further promoted by nickel and cobalt. The activity of the catalysts could be ranked as NiMoS/Fe3S4 > CoMoS/Fe3S4 > MoS2/Fe3S4. Addition of Ni to MoS2 catalyst forms the Ni-Mo-S phase with increased accessible sulfur edge which is responsible for the enhancement in both hydrogenation and desulfurization. The catalyst MoS2 with greigite core and its promoted catalyst NiMoS/CoMoS were also applied to the hydrodeoxygenation (HDO) of stearic acid. HDO was the dominant pathway for all of the catalysts. Catalysts MoS2/Fe3O4 and MoS2/Fe3S4 were used to investigate the roles of H2 and H2S and the involved active sites in the HDS of DBT. Two different active sites for hydrogenation (HYD) and hydrodesulfurization (HDS) were identified. The MoS2 with magnetite core demonstrated high selectivity towards the DDS pathway, which was attributable to the differences in adsorption energy of hydrogen and DBT over hydrogenation and desulfurization sites. H2S is favored being adsorbed on the S-edge vacancies to transfer the active sites to HYD/Isomerization sites. Hydrogen plays three distinctive roles: 1) When adsorbed at Mo edge, hydrogen promotes hydrogenation; 2) Strongly bonded at S-edge it accounts for direct desulfurization; 3) while loosely bonded to S-edge it favors HYD and isomerization."--Pages ii-iii.