Saleem Akthar Farooqui

Development of Hydroprocessing Route to Transportation Fuels from Non-Edible Plant-Oils

Catalysts with tunable porosity, crystallinity and acidity can selectively produce aviation fuels and road transportation fuels via hydroprocessing of non-edible oils. Here we discuss several catalyst supports—mesoporous alumina, silica–alumina and hierarchical mesoporous zeolites, developed and used as support for hydroprocessing catalysts (Ni–Mo, Co–Mo, Ni–W), for the selective production of transportation fuels. These developed catalysts were used for the hydroconversion of waste cooking-oil, jatropha-oil, algal-oil and their mixtures with petroleum refinery oils. The physicochemical properties of the catalyst were tuned for optimal performance on the basis of evaluation results on high pressure fixed bed microreactors and pilot scale reactors. These studies targeted the production of transportation fuels (gasoline, kerosene and diesel) by hydroprocessing (hydrotreating or hydrocracking) renewable feed stocks or co-processing with fossil based oils. Modelling and process optimization studies for prediction of kinetic rate parameters and to know the reaction pathways for the conversion of these feed stocks to various range of hydrocarbon fuels, were also carried out. These studies provided the vital information that the reaction pathways were temperature dependent.

Mesoporous TUD-1 supported indium oxide nanoparticles for epoxidation of styrene using molecular O2

Activation of molecular O2 by metal or metal oxide nanoparticles is an area of recent research interest. In this work, for the first time, we report that indium oxide nanoparticles of <3 nm size dispersed on mesoporous silica (TUD-1) can activate molecular O2 and produce styrene epoxide with a selectivity of 60% and styrene conversion around 25% under mild conditions. It is found that neither indium oxide nor TUD-1 themselves respond to the styrene epoxidation reaction. The computational studies provide evidence that an oxygen molecule is highly polarized when it is located near the interface of both surfaces. The kinetic study shows that the reaction is of pseudo-first order and that the activation energy for styrene conversion is 12.138 kJ mol−1. The catalysts are recyclable for up to four regeneration steps, with the styrene conversion and styrene epoxide selectivity almost unchanged.

Indium oxide nanocluster doped TiO2 catalyst for activation of molecular O2

The In2O3 nanocluster doped faceted nanosize anatase TiO2 can activate molecular O2 for styrene epoxidation reaction. The {001} planes of anatase TiO2 are exposed for 550 °C calcined samples whereas {101} planes are predominantly observed for 450 °C calcined samples. The computational studies highlight that In2O3 is better stabilized on {001} planes of TiO2 resulting in efficient activation of molecular oxygen on In2O3 nanocluster doped {001} faceted TiO2 nanostructures. From the kinetic measurements, it is found that styrene epoxidation reaction is of pseudo-zero order and the corresponding rate constant (k) for the reaction calcined at 450 °C is 0.188 h−1 and at 550 °C it is 0.366 h−1. The activation energy for the reaction is found to be 28.44 kcal mol−1.

Improved hydrogenation function of Pt@SOD incorporated inside sulfided NiMo hydrocracking catalyst

A multifunctional catalyst with Pt incorporated inside sodalite cages (SOD) encapsulated in ZSM-5 supported with Ni and Mo was synthesized, characterized and evaluated as a hydrocracking catalyst for the conversion of triglycerides to kerosene and diesel. The Pt@SOD was further encapsulated inside hierarchical mesoporous ZSM-5 zeolite to prepare a bifunctional catalyst (H-ZSM-5 for acid functionality and sulfided NiMo along with Pt@SOD for hydrogenation functionality). Metal dispersion, temperature programmed reduction (TPR, H2) and temperature programmed desorption (TPD, ammonia) studies were done to evaluate the bifunctional nature of the catalyst. The sulfided NiMo-Pt@SOD-ZSM-5 catalyst showed improved catalytic activity compared to the sulfided NiMo-ZSM-5 catalyst under severe reaction conditions of low hydrogen/feed ratio. We show for the first time that it is possible to operate at low H2 concentrations during hydroprocessing of triglycerides with 99% conversion and 93% selectivity for diesel range compounds at 250 NL L−1 and 380 °C temperature. Computational studies showed that H2 molecules activated by Pt inside the sodalite cages are available for reactions outside the cages. The synthesized catalyst showed high hydrodeoxygenation activity even at lower pressure (50–60 bar) and hydrogen/feed ratios of 500–1500 NL L−1. The catalyst showed better stability against deactivation (4 times less coke deposition) than sulfided NiMo-ZSM-5 catalyst during a continuous run due to the presence of Pt@SOD.

Kinetics and computational fluid dynamics study for Fischer–Tropsch synthesis in microchannel and fixed-bed reactors

The effect of operating conditions on the hydrocarbon yield distribution during Fischer–Tropsch synthesis (FTS) in a microchannel reactor was studied. A power law-based kinetic model was developed for the first time in microchannel and fixed bed reactors for FTS reactions. The activation energy calculated was 90.16 kJ mol−1 and 106.17 kJ mol−1 in the microchannel reactor and fixed bed reactor, respectively. In a single pass run, the CO conversion obtained in the microchannel reactor was more than 92%, while it was 70% in the fixed bed reactor over the same catalyst. The concentration and temperature profile are predicted in both fixed bed and microchannel reactors. As expected, there was no axial concentration gradient observed in the microchannel reactor. Under adiabatic conditions, kinetic and thermodynamic study simulations showed an increase in reactor temperature from 598 K to 639 K in the microchannel reactor and 598 K to 607 K in the fixed bed reactor. The heat produced per unit volume of the microchannel reactor is higher due to a higher rate of the reaction compared to that in the fixed bed reactor.

Aviation Biofuels Through Lipid Hydroprocessing

Hydroprocessing routes to producing alternative aviation fuels have become a well-established technology, though not yet cost-competitive due to the higher cost of animal- and plant-derived triglycerides/lipids. This chapter describes academic and technological advances for the processing of lipids obtained from various sources via hydroprocessing routes to produce biofuels. The effect of different catalytic systems, operating parameters, reaction pathways, and kinetics involved in the hydroprocessing of lipids is also described. Among different catalysts reported and discussed, the sulfided mesoporous catalysts with moderate acidity and higher surface area are similar to currently used hydrocracking catalysts, and are easier to retrofit in the current refinery infrastructure for large-scale production, even under co-processing conditions. In addition to reaction chemistry and conditions, this chapter also discusses technical challenges, such as the high exothermicity observed during the reaction, pretreatment strategies for increased catalyst life, recycled gas purification issues, and regular feedstock availability, etc., that must be overcome for commercialization of this process for production of aviation biofuels.