The primary objective of the research project was to further develop a computer program modeling the hydrocracking of partially hydrogenated vacuum gas oil (HVGO), and to use the model to compare the theoretical product distribution to experimental data describing the product distribution of an industrial pilot reactor. The hydrocracking of HVGO on acid zeolites is effectively modeled utilizing a single-event kinetic approach developed by Froment and coworkers. The hydrocracking of HVGO can be described in terms of the fundamental reaction steps involving carbenium ions. Some 45 single-event rate parameters are used to dictate the rate of each single-event in the reaction network. The composition of the partially hydrogenated feed stock is detailed up to C33. Each component and lump is considered in terms of the elementary steps to generate a network of continuity equations and single-event rate parameters. A reactor model comprising this kinetic model can be used to simulate the isothermal and nonisothermal hydrocracking of a HVGO feed stock. The results are represented in terms of the yields of 241 lumps and components in the gas phase and 241 components and lumps in the liquid phase. The predicted yields of various commercial oil fractions and particular components are then compared to experimental data from an industrial pilot reactor to verify the accuracy of the model and the single-event rate parameters.

In this study commercial ultrastable Y zeolite was modified by different synthesis methods as precipitation, impregnation, and thermal hydrolysis, with different titanium and zirconium precursors. The intention was to investigate the effect of these metals in the framework on the zeolite acidity properties and how this influences the performance of the final catalyst on oil processes such as hydrocracking. For precipitation modification, different samples were synthesized varying the time precipitating ranging from one injection up to 9 hours. Samples in impregnation modification were synthesized along with thermal hydrolysis to compare different modification synthesis methods. Zeolite has a strong dealumination effect below pH 2 but low pH is needed to maintain titanium precursor in solution. Thermal hydrolysis shows an improvement in activity compared to precipitation and impregnation better selectivity compared to thermal hydrolysis. Metals preserve aluminum content when exposed to acidic post-treatment and shows improvements in yield of isomers compared to blanks. NH3-TPD showed decrease of weak and strong acid sites with increase of medium acid sites when exposed to acid post-treatment. BAS controls the yield of isomers.

Increased research efforts have recently been accelerated to develop liquid transportation fuels from bio-oil produced by fast pyrolysis. However, these bio-oils contain high levels of oxygenated compounds that require removal to produce viable transportation fuels. A variety of upgrading technologies have been proposed, of which catalytic hydroprocessing of the raw bio-oil has appears to have the best potential due to the fact that no fractionation of the bio-oil is required prior to treatment. The objective of this research was to apply two-stage catalytic hydroprocessing to bio-oil with heterogeneous catalysts to produce hydrocarbon fuels. To achieve this objective seven catalysts were initially compared in first-stage hydrotreating reactions. The result of the comparison of the seven hydrotreating catalysts showed that the MSU-1 catalyst had the significantly highest yield at 38 wt%, had the highest H/C ratio, and reduced oxygen adequately. The MSU-1 catalyst had an energy efficiency of 80%, reduced acid value by 45% and water content by 78%. Higher heating value was doubled by the hydrotreating process of raw bio-oil. Three catalysts were compared as second-stage hydrocracking catalysts. All liquid organic products produced by the catalytic reactions were compared with regard to yield and chemical and physical qualities. Results from these experiments showed that the MSU-2 catalyst had the significantly highest yield at 68 wt%; oxygen value was significantly lower than for the compared catalysts at zero percent. MSU-2 also produced the lowest amount of char at 3.5 wt%. Additionally, MSU-2 produced a high volume of methane gas as a byproduct, with a high value for utilization for production of process heat. A study of reaction time optimization found that best results from application of MSU-2 were for the shortest reaction time of 1 h. This short reaction time is important to reduce hydroprocessing costs. Simulated distillation of hydrocarbon mix results in distribution of these by fuel weights with gasoline comprising 37%, jet fuel 27%, diesel 25% and heavy fuel oil 11%.The energy efficiency of the hydrocracking of first-stage stabilized bio-oil with MSU-2 catalyst was 93.61%.

This dissertation includes two process modeling studies -- (1) predictive modeling of large-scale integrated refinery reaction and fractionation systems from plant data – hydrocracking process; and (2) integrated process modeling and product design of biodiesel manufacturing. \r\n1. Predictive Modeling of Large-Scale Integrated Refinery Reaction and Fractionation Systems from Plant Data -- Hydrocracking Processes: This work represents a workflow to develop, validate and apply a predictive model for rating and optimization of large-scale integrated refinery reaction and fractionation systems from plant data. We demonstrate the workflow with two commercial processes -- medium-pressure hydrocracking unit with a feed capacity of 1 million ton per year and high-pressure hydrocracking unit with a feed capacity of 2 million ton per year in the Asia Pacific. This work represents the detailed procedure for data acquisition to ensure accurate mass balances, and for implementing the workflow using Excel spreadsheets and a commercial software tool, Aspen HYSYS from Aspen Technology, Inc. The workflow includes special tools to facilitate an accurate transition from lumped kinetic components used in reactor modeling to the boiling point based pseudo-components required in the rigorous tray-by-tray distillation simulation. Two to three months of plant data are used to validate models' predictability. The resulting models accurately predict unit performance, product yields, and fuel properties from the corresponding operating conditions.\r\n2. Integrated Process Modeling and Product Design of Biodiesel Manufacturing: This work represents first a comprehensive review of published literature pertaining to developing an integrated process modeling and product design of biodiesel manufacturing, and identifies those deficient areas for further development. It also represents new modeling tools and a methodology for the integrated process modeling and product design of an entire biodiesel manufacturing train. We demonstrate the methodology by simulating an integrated process to predict reactor and \r\nseparator performance, stream conditions, and product qualities with different feedstocks. The results show that the methodology is effective not only for the rating and optimization of an existing biodiesel manufacturing, and but also for the design of a new process to produce biodiesel with specified fuel properties. / Ph. D.

A mechanistic kinetic model for the hydrocracking of paraffins based on the single-event kinetics approach has been studied. Several elements of the model have been improved and the parameters of the model have been estimated from experimental data on n-hexadecane hydrocracking. A detailed reaction network of elementary steps has been generated based on the carbenium ion chemistry using the Boolean relation matrices. A total of 49,636 elementary steps are involved in the hydrocracking of n-hexadecane. The rate coefficients of these elementary steps are expressed in terms of a limited number of single event rate coefficients. By virtue of the single event concept, the single event rate coefficients of a given type of elementary steps are independent of the structure of reactant and product. Given their fundamental nature they are also independent of the feedstock composition and the reactor configuration. There is no lumping of components involved in the generation of the reaction network. Partial lumping is introduced only at a later stage of the model development and the lumping is strictly based on the criterion that the individual components in any lump will be in thermodynamic equilibrium. This definition of lumping requires a total of 49 pure components/lumps in the kinetic model for the hydrocracking of n-hexadecane. The "global" rate of reaction of a lump to another lump is expressed using lumping coefficients which account for the transformation of all the components of one lump into the components of another lump through to a given type of elementary steps. The rate expressions thus formulated are inserted into a one-dimensional, three-phase plug flow reactor model. Experimental data have been collected for the hydrocracking of n-hexadecane. The model parameters are estimated by constrained optimization using sequential quadratic programming by minimizing the sum of squares of residuals between experimental and model predicted product profiles. The optimized parameters are finally used for the reactor simulation to study the effect of different process variables on the conversion and product distribution of n-hexadecane hydrocracking. The model is also used to predict the product distribution for the hydrocracking of a heavy paraffinic mixture consisting of C9 to C33 normal paraffins.

Hydrocracking of plastic wastes offers the best value in terms of quality of its process oil product among other feedstock recycling methods capable of recycling mixed plastic waste; a paraffin-rich synthetic crude similar in composition to gasoline and diesel is produced. Additional benefits of the process include heteroatom removal, catalyst conservation as well as a lower process temperature. However PVC content in mixed plastics waste and the high viscosity of plastics are prominent issues in relation to subjecting plastics to petrochemical processes such as hydrocracking. A 5ppm chlorine limit and maximum feedstock viscosity of 0.5 Pas at 200oC is tolerable in the petrochemical industry. Although dechlorination of mixed plastic waste has been studied exhaustively, viscosity studies in relation to process improvement or efficiency in the pyrolysis or hydrocracking of plastics haven’t received as much attention. Viscosity has been identified as being inhibitive to heat and mass transfer, and transport into reactors, as well as being a major problem in relation to designing reactors for feedstock recycling. In this research, four of the main polymer types; high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE), Polypropylene (PP), Polystyrene (PS) and Polyethylene Terephthalate (PET) were rheological characterised to establish the extent to which they exceed the recommended viscosity in the petroleum industry. Viscosities 400 – 1200 times the feedstock viscosity in the petrochemical industry at a shear rate of 500s-1, which is typical for pumping and atomisation operations, were obtained during the characterisation of the plastic samples in a conventional capillary rheometer. Saturated chain hydrocarbon solvents (iso-octane, decane, tetradecane, pentadecane and hexadecane) were investigated for treating HDPE, in a range of HDPE-solvent mixtures, in order to reduce its viscosity. Preliminary results of differential scanning calorimetry tests carried out on the solvent-treated HDPE revealed a 12 – 16% drop in the melting peak temperature of the pure HDPE (129 oC) using tetradecane (108 oC), pentadecane (110 oC) and hexadecane (113 oC) for the 20:80 PE-solvent mixtures. iso-octane and decane however only produced a viscosity drop of 3% and 4% respectively for the same 20:80 PE-solvent mixtures. Thermal stability of HDPE was largely unaffected by the solvent treatment except in the case of pentadecane which showed a reducing trend on the decomposition onset temperature as solvent concentration in the starting mixtures was increased, albeit marginal (from 441oC to 437oC). A custom built sealed-vessel impeller viscometer designed to facilitate the treatment of the HDPE via solvent refluxing and in situ viscosity measurement was calibrated by determining constants which enable the conversion of machine data to viscosity and shear rate using Newtonian and non-Newtonian calibration fluids. These constants, the shape factor and shear rate conversion factor, were determined to be 81.03 and 22.08, respectively, with corresponding 95% confidence limits of 79.21 and 86.26, and 21.47 and 24.00. Viscosity measurements of a 40:60 PE-nC15 mixture carried out in the sealed-vessel impeller viscometer at a shear rate of between 71s-1 and 80s-1 at 95% confidence level and 250oC was 7 Pas representing approximately 200 fold reduction from the virgin HDPE measured in the conventional capillary rheometer.

Bifunctional catalysts consisting of palladium or platinum and supported on amorphous silica-alumina were prepared and tested in the hydrocracking of n-hexadecane, which is considered to be representative of n-paraffins in hydrocracker feeds. In addition to the evaluation of the  physicochemical properties, a comprehensive study on catalyst activity and selectivity has been conducted, in the full range of conversions. A theoretical model was proposed to fit the experimental conversion-selectivity data. The n-hexadecane reactivity pattern was expressed in terms of a reaction network involving lumps consisting of monobranched and multibranched n-hexadecane isomers, and cracking products. Pseudo first order kinetics and irreversible reaction steps were assumed in order to obtain the kinetic constants of each step. For the same metallic molar loading, a platinum-based catalyst proved more active than a palladium one. The reaction network model showed that cracking products were produced by means of a bifunctional mechanism on palladium catalysts, with n-hexadecane isomers as intermediates. However, on platinum catalysts, an additional monofunctional mechanism was observed. The noble metal catalyzes the hydrogenolysis of n-hexadecane without requiring any acid function. An increase in the platinum loading leads to an increase in the importance of this direct cracking route. The deactivation in the platinum-based catalysts is only due to coke formation, which deactivates the metal sites. The regeneration by means of a Temperature-Programmed Oxidation does not lead to a complete recovery of the metal function, according to the volumetric chemisorption measurements and the experimental selectivity  data. Further work is required to determine the real causes.

Fischer-Tropsch synthesis enables the production of high quality diesel fuel from biomass derived synthesis gas. In order to increase the overall diesel yield, it is necessary to perform a subsequent hydrocracking of the long-chain linear paraffins. This work is focused on characterization and testing of catalysts for the hydrocracking reaction of Fischer-Tropsch waxes. In particular, noble metal catalyst based on Pt and Pd on amorphous silica-alumina support were tested. Palladium based catalysts performed nearly an ideal bifunctional mechanism, while platinum based catalysts performed another way of cracking: hydrogenolysis. Platinum based catalysts are more active than palladium ones, with the same metal loading. This is a consequence of the nature of the metal sites. The product distribution is similar for both platinum and palladium catalysts. However, due to the hydrogenolysis cracking mechanism performed by platinum based catalysts, the amount of light gases produced on platinum based catalysts is higher. Furthermore, the deactivation behavior of the Platinum and Palladium catalysts has been studied, and the results showed that the dispersion of the active phase decreased with deactivation and the average crystallite diameter increased. This means a decrease in activity. A regeneration program, temperature programmed oxidation (TPO), has been carried out demonstrating that the activity was not completely recovered.

Hydrocracking is one of the most essential catalytic processes in the oil industry for the conversion of heavy fractions of petroleum (light and heavy vacuum gas oil, demetallized oil) and renewable hydrocarbon feedstocks to high-quality fuels. Hydrocracking relies on a bifunctional catalytic process that combines catalytic cracking and hydrogenation steps. In principle, hydrocracking is aimed to convert heavy and ultraheavy oils with maximum fuel selectivity and minimum formation of light gases and polyaromatic compounds, from this high activity and selectivity of the catalyst, is achieved by finding a good balance between its acidic and hydrogenation properties. For this study, platinum catalyst impregnated on alumina was applied for hydrogenation reaction, whereas cracking function was accomplished by ultrastable Y (USY) zeolite. The central objective of the thesis was to study the fundamental effect of extra framework aluminum (EFAl) species forming with the hydrothermal treatment of USY on hydrocracking of selected model compound – n-hexadecane. Three commercial USY zeolites with different SiO2/Al2O3 ratios were steamed until they reached down to the conversion curve of the reference USY sample physically mixed with 1% Pt supported on alumina in a 1:10 ratio. XRD patterns showed that the crystalline faujasite structure was kept after steaming. In the physisorption of argon, slight changes were observed in surface area and pore volumes which were correlated to the structural collapse of the zeolite framework. Dealumination of the zeolite framework was verified by 27Al MAS NMR. FTIR spectroscopy of pyridine adsorption and TPD of ammonia were employed to investigate the acidity of the samples. From the results, it was found that the concentration of Brønsted acid sites was the main contributor to the activity-acidity relationship in n-hexadecane hydrocracking. To gain more insight into the relationship, samples were subjected to n-hexane cracking. Turnover frequency analysis supported the proposal about hydrocracking reaction and also revealed the chemical influence of EFAl on Brønsted acidity observed in catalytic cracking of hexane.

L'hydrocraquage est un procédé catalytique majeur dans la valorisation des coupes pétrolières lourdes. Il met en jeu un catalyseur bifonctionnel composé d’une phase métallique et d’une phase acide. Sur la première, ont lieu des réactions d’hydrogénation/déshydrogénation, et, sur la seconde, des réactions de protonation/déprotonation, d’isomérisation et de craquage. La modélisation joue un rôle essentiel dans la compréhension du procédé et dans son optimisation. Dans le cadre de cette thèse, elle s'effectue en deux étapes. La première étape consiste à déterminer la composition de la charge, et, la seconde repose sur le développement d’un modèle cinétique considérant l'ensemble des réactions.Actuellement puisque les techniques analytiques ne permettent pas de caractériser avec précision des charges aussi complexes, une reconstruction moléculaire est nécessaire. La méthode retenue consiste tout d’abord à établir une bibliothèque de molécules en se basant sur les résultats d’une méthode analytique développée à IFPEN, la GC-2D/HT. Puis, la charge est partagée en trois groupes en fonction de la température d’ébullition des molécules : une coupe naphta, une coupe kérosène/gazole et une coupe lourde. Pour chaque groupe une méthode de reconstruction moléculaire différente est appliquée : l’utilisation directe des résultats analytiques, la reconstruction statistique et la maximisation d’entropie respectivement. Pour le modèle cinétique, l’objectif est double. D’une part, il doit prendre en compte les réactions d’hydrogénation/déshydrogénation des molécules aromatiques intervenant sur la phase métallique du catalyseur. D’autre part pour la phase acide, la méthode retenue, qui est celle des Evènements Constitutifs couplée à la méthode des Chaînes Latérales, doit être étendue aux molécules cycliques.Finalement, le modèle permet de simuler le procédé d’hydrocraquage dans des conditions proches de celles industrielles. / Hydrocracking is a catalytic cracking process converting high-boiling petroleum fractions into lower-boiling and more valuable ones. It is carried out on bifunctional catalyst combining both a metal phase and an acid phase. On the metal phase, hydrogenation/dehydrogenation reactions take place while on the acid phase, protonation/deprotonation, isomerization and cracking reactions occur. To optimize the yield of the desired products, hydrocracking modeling is essential. The developed model considers a hydrotreated feedstock composed of aromatic, naphthenic and paraffinic hydrocarbons. Its purposes are both to realize a relevant molecular reconstruction of the effluents and a kinetic model representative of the industrial context. As analytical techniques are not yet powerful enough to detect and quantify in detail all the components of the effluents, a molecular reconstruction is required. The proposed method is to create first a set of molecules thanks to analytical results provided by high-temperature two-dimensional gas chromatography. Then, depending on molecules’ boiling point, the effluents are shared into three groups: the naphtha cut, the gas oil cut and the “heavy cut”. For each of them, a particular reconstruction method is applied: direct use of analytical results, the statistical method and the entropy maximization method respectively.For the kinetic model, goals are both to introduce the aromatic and naphthenic hydrocarbons in the model and to consider the reactions on the metal and acid phases. So first, a reaction mechanism of aromatics hydrogenation/dehydrogenation has been defined and implemented. Secondly for the acid phase, the kinetic model based on the Single-Event approach associated with the Lateral Chain method has been improved to consider not only paraffinic but also naphthenic and aromatic hydrocarbons. Finally, the model allows to simulate the hydrocracking process in industrial conditions.