A rigorous kinetic model of hydrodesulfurization (HDS) of complex mixtures such as light cycle oil (LCO) or diesel has been developed. An experimental setup was constructed to investigate the hydrotreatment of complex mixtures. The hydrodesulfurization of LCO on a commercial CoMo/Al2O3 (IMP) catalyst was investigated in a Robinson Mahoney perfectly mixed flow stationary basket reactor. An experimental investigation of the HDS of the dibenzothiophene (DBT) and substituted dibenzothiophenes in the LCO was carried out at temperatures between 290 and 330°C, space time for dibenzothiophene (W/F0 DBT) between 1000 and 6500 kgcat-h/kmol, and H2/HC molar ratio constant of 2.8. To avoid having to deal with a huge number of parameters in the model, a methodology based on structural contributions was applied. DENs and DENt are the denominators of the Hougen-Watson rate expressions for hydrodesulfurization of dibenzothiophene (DBT) and methyl-substituted dibenzothiophenes contained in the LCO. Both denominators comprise the concentration of all adsorbing species of the LCO multiplied by their adsorption equilibrium constants. The estimation of the denominators DENs and DENt was performed using the Levenberg-Marquardt algorithm and the results in terms of conversion for DBT, biphenyl and cyclohexylbenzene obtained in the hydrodesulfurization of the LCO. The evolution of DENs and DENt values with the composition was calculated for each LCO experiment. Structural contributions were taken from Vanrysselberghe and Froment for hydrogenolysis and hydrogenation of methyl-substituted dibenzothiophenes with a significant reduction in the number of parameters to be estimated in the HDS of the LCO. The multiplication factors, fsDBT, which are products of structural contributions for hydrogenolysis and hydrogenation of the mono- and dimethyl-dibenzothiophenes were also taken from Vanrysselberghe and Froment. These multiplication factors are based on experimental results with model components such as DBT, 4-Methyl dibenzothiophene and 4,6-Dimethyl dibenzothiophene. The results obtained in the modeling are in good agreement with the experimental data because the model reproduces very well the observed total conversions of DBT, conversions of DBT into biphenyl and conversions of DBT into cyclohexylbenzene as a function of temperature.

Aeroelasticidade não linear é uma área multidisciplinar e importante em engenharia aeronáutica e aeroespacial. Aeroelasticidade é o estudo do mecanismo de interação entre os esforços aerodinâmicos e dinâmico-estruturais. Os avanços nas técnicas de CFD se concentram nas aplicações de problemas aerodinâmicos cada vez mais complexos, como os fenômenos associados com a formação e movimento das ondas de choque em escoamentos transônicos e escoamentos separados. Com os desenvolvimentos dos códigos de CFD, o tratamento de problemas aeroelásticos por meio de abordagens computacionais é denominado aeroelasticidade computacional. O objetivo deste trabalho é apresentar uma análise dos efeitos não lineares em aeroelasticidade no domínio do tempo em regime transônico. A metodologia proposta pretende investigar os efeitos não lineares em aerofólios onde são consideradas as não linearidades estruturais e aerodinâmicas. Neste trabalho as não linearidades aerodinâmicas estão associadas à formação e ao passeio das ondas de choque. Nesta situação, verifica-se que a fronteira de ocorrência de flutter é degradada rapidamente na faixa de vôo transônico, onde este fenômeno é denominado de depressão transônica. Dois códigos de CFD foram considerados, ambos baseados na formulação de Euler. Para a solução do sistema aeroelástico no domínio do tempo é aplicado o método Runge-Kutta combinado com o código de CFD. Neste caso, o código de CFD não estacionário é construído em um contexto de malhas não estruturadas. Esta consiste da primeira análise aeroelástica através da metodologia de marcha no tempo utilizando este código de CFD. As respostas aeroelásticas se concentram particularmente para o aerofólio NACA0012 através da história no tempo e retrato de fase para investigar os efeitos típicos não lineares como oscilações em ciclos limite, assim como, são construídas as fronteiras de flutter. Para o cálculo direto da fronteira de flutter é utilizado o código da análise de bifurcação de Hopf, onde o modelo de CFD é baseado no contexto de malhas estruturadas. Em trabalhos anteriores com este código foram obtidas as fronteiras do flutter em perfis e asas simétricos com modelos estruturais lineares. Este trabalho apresenta a primeira análise deste código considerando o modelo estrutural não linear. As não linearidades estruturais concentradas mostraram ter um efeito significativo na resposta aeroelástica podendo ser observadas as oscilações em ciclos limite abaixo da fronteira de flutter. As metodologias de marcha no tempo e análise de bifurcação de Hopf foram comparadas e os resultados apresentaram boa concordância. Isto comprovou a confiabilidade das duas metodologias na análise dos efeitos não lineares em aeroelasticidade. As análises de marcha no tempo com o modelo estrutural não linear também foram realizadas após a ocorrência do flutter e sua influência nas oscilações em ciclos limite foram observadas. / Nonlinear aeroelasticity is a multidisciplinary field, that is important in aeronautics and aerospace engineering. Aeroelasticity can be defined as the science which studies the mutual interaction between aerodynamic and dynamic forces. Computational fluid dynamics (CFD) has matured to the point where it is being applied to complex problems in external aerodynamics, particulary for phenomena associated with shock motions or separation. These two observations have motivated the development of CFD-based aeroelastic simulation, a fiel now being called computational aeroelasticity. The nonlinearities in the aeroelastic analysis are divided into aerodynamic and structural ones. The aim of this work is concerned with an application of time domain analysis for aeroelastic problems in a transonic flow. The methodology here proposed is to present an investigation on the effects of nonlinearities on airfoil flutter where both aerodynamic and structural concentrated nonlinearities are considered. In this work the aerodynamic nonlinearity arises from the presence of shock waves in transonic flows. In this situation, the unsteady forces generated by motion of the shock wave have been shown to destabilize single degree-of-freedom airfoil pitching motion and affect the bending-torsional flutter by lowering the flutter speed at the so-called transonic dip phenomenon. Two CFD tools are employed in the present work and they are based on the Euler formulation. To solve the aeroelastic problem the Runge-Kutta method is applied combined with the CFD code. In this case, the unsteady CFD tool solves flows in the an unstructured computational domain discretisation. This CFD tool had never been used for time domain aeroelastic analysis before. The responses concerned particularly the NACA0012 airfoil by investigating flutter boundary and typical LCO nonlinear effects from phase plane. For direct flutter boundary calculation, Hopf bifurcation analysis is employed, where the CFD code is based on structured grids for computation domain discretisation. Previous work has demonstrated the scheme for both symmetric airfoil and wing with linear structural model. The current work presents the first investigations of the structural nonlinearities effects with the method. The concentrated nonlinearities show to have significant effects on the aeroelastic responses and to provide limit cycle oscillation (LCO) below the flutter speed. Time marching analysis is performed and compared with direct calculation of Hopf bifurcation points. The results agree well and these computational tools have shown to be powerful to analyse nonlinear effects in aeroelasticity. Post bifurcation behavior is analysed to show influence of nonlinear structural terms on LCO with the time marching solver.

Aeroelasticidade não linear é uma área multidisciplinar e importante em engenharia aeronáutica e aeroespacial. Aeroelasticidade é o estudo do mecanismo de interação entre os esforços aerodinâmicos e dinâmico-estruturais. Os avanços nas técnicas de CFD se concentram nas aplicações de problemas aerodinâmicos cada vez mais complexos, como os fenômenos associados com a formação e movimento das ondas de choque em escoamentos transônicos e escoamentos separados. Com os desenvolvimentos dos códigos de CFD, o tratamento de problemas aeroelásticos por meio de abordagens computacionais é denominado aeroelasticidade computacional. O objetivo deste trabalho é apresentar uma análise dos efeitos não lineares em aeroelasticidade no domínio do tempo em regime transônico. A metodologia proposta pretende investigar os efeitos não lineares em aerofólios onde são consideradas as não linearidades estruturais e aerodinâmicas. Neste trabalho as não linearidades aerodinâmicas estão associadas à formação e ao passeio das ondas de choque. Nesta situação, verifica-se que a fronteira de ocorrência de flutter é degradada rapidamente na faixa de vôo transônico, onde este fenômeno é denominado de depressão transônica. Dois códigos de CFD foram considerados, ambos baseados na formulação de Euler. Para a solução do sistema aeroelástico no domínio do tempo é aplicado o método Runge-Kutta combinado com o código de CFD. Neste caso, o código de CFD não estacionário é construído em um contexto de malhas não estruturadas. Esta consiste da primeira análise aeroelástica através da metodologia de marcha no tempo utilizando este código de CFD. As respostas aeroelásticas se concentram particularmente para o aerofólio NACA0012 através da história no tempo e retrato de fase para investigar os efeitos típicos não lineares como oscilações em ciclos limite, assim como, são construídas as fronteiras de flutter. Para o cálculo direto da fronteira de flutter é utilizado o código da análise de bifurcação de Hopf, onde o modelo de CFD é baseado no contexto de malhas estruturadas. Em trabalhos anteriores com este código foram obtidas as fronteiras do flutter em perfis e asas simétricos com modelos estruturais lineares. Este trabalho apresenta a primeira análise deste código considerando o modelo estrutural não linear. As não linearidades estruturais concentradas mostraram ter um efeito significativo na resposta aeroelástica podendo ser observadas as oscilações em ciclos limite abaixo da fronteira de flutter. As metodologias de marcha no tempo e análise de bifurcação de Hopf foram comparadas e os resultados apresentaram boa concordância. Isto comprovou a confiabilidade das duas metodologias na análise dos efeitos não lineares em aeroelasticidade. As análises de marcha no tempo com o modelo estrutural não linear também foram realizadas após a ocorrência do flutter e sua influência nas oscilações em ciclos limite foram observadas. / Nonlinear aeroelasticity is a multidisciplinary field, that is important in aeronautics and aerospace engineering. Aeroelasticity can be defined as the science which studies the mutual interaction between aerodynamic and dynamic forces. Computational fluid dynamics (CFD) has matured to the point where it is being applied to complex problems in external aerodynamics, particulary for phenomena associated with shock motions or separation. These two observations have motivated the development of CFD-based aeroelastic simulation, a fiel now being called computational aeroelasticity. The nonlinearities in the aeroelastic analysis are divided into aerodynamic and structural ones. The aim of this work is concerned with an application of time domain analysis for aeroelastic problems in a transonic flow. The methodology here proposed is to present an investigation on the effects of nonlinearities on airfoil flutter where both aerodynamic and structural concentrated nonlinearities are considered. In this work the aerodynamic nonlinearity arises from the presence of shock waves in transonic flows. In this situation, the unsteady forces generated by motion of the shock wave have been shown to destabilize single degree-of-freedom airfoil pitching motion and affect the bending-torsional flutter by lowering the flutter speed at the so-called transonic dip phenomenon. Two CFD tools are employed in the present work and they are based on the Euler formulation. To solve the aeroelastic problem the Runge-Kutta method is applied combined with the CFD code. In this case, the unsteady CFD tool solves flows in the an unstructured computational domain discretisation. This CFD tool had never been used for time domain aeroelastic analysis before. The responses concerned particularly the NACA0012 airfoil by investigating flutter boundary and typical LCO nonlinear effects from phase plane. For direct flutter boundary calculation, Hopf bifurcation analysis is employed, where the CFD code is based on structured grids for computation domain discretisation. Previous work has demonstrated the scheme for both symmetric airfoil and wing with linear structural model. The current work presents the first investigations of the structural nonlinearities effects with the method. The concentrated nonlinearities show to have significant effects on the aeroelastic responses and to provide limit cycle oscillation (LCO) below the flutter speed. Time marching analysis is performed and compared with direct calculation of Hopf bifurcation points. The results agree well and these computational tools have shown to be powerful to analyse nonlinear effects in aeroelasticity. Post bifurcation behavior is analysed to show influence of nonlinear structural terms on LCO with the time marching solver.

The author develops a nonlinear longitudinal model of an aircraft modeled by rigid fuselage, tail, and wing, where the wing is attached to the fuselage with a torsional spring. The main focus of this research is to retain the full nonlinearities associated with the system and to perform gust load alleviation for the model by comparing the impact of a proportional-integral- lter nonzero setpoint linear controller with control rate weighting and a nonlinear Lyapunov-based controller. The four degree of freedom longitudinal system under consideration includes the traditional longitudinal three degree of freedom aircraft model and one additional degree of freedom due to the torsion from the wing attachment. Computational simulations are performed to show the aeroelastic response of the aircraft due to a gust load disturbance with and without control. Results presented in this thesis show that the linear model fails to capture the true nonlinear response of the system and the linear controller based on the linear model does not stabilize the nonlinear system. The results from the Lyapunov-based control demonstrate the ability to stabilize the nonlinear response, including the presence of an LCO, and emphasize the importance of examining the fully nonlinear system with a nonlinear controller.

Recently, the production of lithium-ion batteries (LIB) has grown rapidly, highlighting the need for efficient and environmentally friendly recycling of LIB waste. In this work, the usage of so-called deep eutectic solvents (DESs) for the leaching of the LIB cathode material lithium cobaltoxide is investigated. The initial DESs investigated are mixtures of poly(ethylene glycol) (PEG200) and an organic acid: tartaric, ascorbic, citric, oxalic or succinic acid (PEG:TA (4:1), PEG:AA (8:1), PEG:CA (4:1), PEG:OA (2:1) and PEG:SA (6:1), the molar ratio in parenthesis). Thermogravimetric analysis shows that the solvents are stable up to 180-190 °C. DESs were analyzed with FTIR spectroscopy, pH was measured using a pH-meter and viscosity using a rolling-ball viscometer. The highest leaching efficiency was obtained using PEG:AA followed by PEG:OA, both having the ability to reduce Co(III). This ability was dominant over pH and viscosity influence. For the other three solvents, leaching efficiency increases in the order of decreasing pH (PEG:TA>PEG:CA>PEG:SA). More investigations of leaching as a function of time are needed to determine the impact of viscosity. PEG:CA and PEG:AA are used to study the impact of solid-to-liquid ratio. For PEG:AA the optimal S/L-ratio is 20 mg/g. For PEG:CA the optimal S/L-ratio is different for Li and Co. Three additional CA based DESs are made using ethylene glycol (EG) and choline chloride (ChCl): EG:CA, ChCl:EG:CA and ChCl:PEG:CA. Adding ChCl to EG:CA and PEG:CA increases the leaching efficiency from ca 5 and 10 to ca 30% and the color changes from pink to blue, indicating the formation of tetrachlorocobalt complexes. This reaction may produce chlorine gas, although none was detected using potassium iodide starch paper. Study of leaching as afunction of time of ChCl:EG:CA shows the reaction slows down significantly after 24 h, indicating that the reaction has reached or is near equilibrium at this point. Antisolvent crystallization of this solvent using ethanol was not succesful.

Une nouvelle méthodologie de modélisation cinétique des procédés de raffinage traitant les charges lourdes a été développée. Elle modélise, au niveau moléculaire, la composition de la charge et les réactions mises en œuvre dans le procédé.La composition de la charge est modélisée à travers un mélange de molécules dont les propriétés sont proches de celles de la charge. Le mélange de molécules est généré par une méthode de reconstruction moléculaire en deux étapes. Dans la première étape, les molécules sont créées par assemblage de blocs structuraux de manière stochastique. Dans la deuxième étape, les fractions molaires sont ajustées en maximisant un critère d’entropie d’information.Le procédé de raffinage est ensuite simulé en appliquant, réaction par réaction, ses principales transformations sur le mélange de molécules, à l'aide d'un algorithme de Monte Carlo.Cette méthodologie est appliquée à deux cas particuliers : l’hydrotraitement de gazoles et l’hydroconversion de résidus sous vide (RSV). Pour le premier cas, les propriétés globales de l’effluent sont bien prédites, ainsi que certaines propriétés moléculaires qui ne sont pas accessibles dans les modèles traditionnels. Pour l'hydroconversion de RSV, dont la structure moléculaire est nettement plus complexe, la conversion des coupes lourdes est correctement reproduite. Par contre, la prédiction des rendements en coupes légères et de la performance en désulfuration est moins précise. Pour les améliorer, il faut d'une part inclure de nouvelles réactions d'ouverture de cycle et d'autre part mieux représenter la charge en tenant compte des informations moléculaires issues des analyses des coupes de l'effluent. / In the present PhD thesis, a novel methodology for the kinetic modelling of heavy oil refining processes is developed. The methodology models both the feedstock composition and the process reactions at a molecular level. The composition modelling consists of generating a set of molecules whose properties are close to those obtained from the process feedstock analyses. The set of molecules is generated by a two-step molecular reconstruction algorithm. In the first step, an equimolar set of molecules is built by assembling structural blocks in a stochastic manner. In the second step, the mole fractions of the molecules are adjusted by maximizing an information entropy criterion. The refining process is then simulated by applying, step by step, its main reactions to the set of molecules, by a Monte Carlo method. This methodology has been applied to two refining processes: The hydrotreating (HDT) of Light Cycle Oil (LCO) gas oils and the hydroconversion of vacuum residues (VR). For the HDT of LCO gas oils, the overall properties of the effluent are well predicted. The methodology is also able to predict molecular properties of the effluent that are not accessible from traditional kinetic models. For the hydroconversion of VR, which have more complex molecules than LCO gas oils, the conversion of heavy fractions is correctly predicted. However, the results for the composition of lighter fractions and the desulfurization yield are less accurate. To improve them, one must on one hand include new ring opening reactions and on the other hand refine the feedstock representation by using additional molecular information from the analyses of the process effluents.

<p>The global oil refining industry with its present shift inproduct distribution towards fuels such as gasoline and dieselwill most likely hold the fort for many years to come. However,times will change and survival will very much depend onprocessing flexibility and being at the frontiers of refiningtechnology, a technology where catalysts play leading roles.Today oil refiners are faced with the challenge to producefuels that meet increasingly tight environmentalspecifications, in particular with respect to maximum sulphurcontent. At the same time, the quality of crude oil is becomingworse with higher amounts of polyaromatics, heteroatoms(sulphur and nitrogen) and heavy metals. In order to staycompetitive, it is desirable to upgrade dense streams withinthe refinery to value-added products. For example, upgradingthe fluid catalytic cracking (FCC) by-product light cycle oil(LCO) into a high quality diesel blending component is a veryattractive route and might involve a two-step catalyticprocess. In the first step the LCO is hydrotreated andheteroatoms are removed and polyaromatics are saturated, in thesecond step naphthenic rings are selectively opened to improvethe cetane number of the final product.</p><p>The present research is devoted to the second catalytic stepof LCO upgrading and was carried out within the framework of aEuropean Union project entitled RESCATS.</p><p>From the patent literature it is evident that iridium-basedcatalysts seem to be good candidates for ring-opening purposes.A literature survey covering ring opening of naphthenicmolecules shows the need for extending investigations toheavier model substances, more representative of the dieselfraction than model compounds such as alkylated mono C5 and C6-naphthenic rings frequently employed in academic studies.</p><p>Ring-opening catalysts, mainly Pt-Ir based, were synthesisedat KTH by two different methods: the microemulsion and theincipient wetness methods. Characterization of the catalystswas performed using a number of techniques including TPR,TEM-EDX, AFM and XPS etc. Catalytic screening at atmosphericpressure using pure indan as model substance was utilized todetect ring-opening activity and the magnitude of selectivityto desired cetane-boosting products. The development of suchring-opening catalysts is the topic of Paper I.</p><p>When designing a catalytic system aimed at refiningpetroleum, it is crucial to monitor the evolution of thesulphur distribution throughout the different stages of theprocess so that catalyst properties and reaction parameters canbe optimised. The final section of this thesis and Paper II arethus devoted to high-resolution sulphur distribution analysisby means of a sulphur chemiluminescence detector (SCD).</p><p><b>Keywords:</b>ring opening, naphthenes, cetane numberimprovement, indan, light cycle oil (LCO), Pt-Ir catalyst,catalyst characterization, aromatic sulphur compounds, GC-SCD,distribution, analysis.</p>

This work describes two phase field models for the simulation of the interface evolution between a LiCoO2 cathode (LCO) and a Li7La3Zr2O12 solid electrolyte (LLZO) in a Li-metal/LLZO/LCO battery during high temperature sintering. In these conditions atomic species tend to diffuse into the opposing material, creating an intermediate layer of mixed composition which resists the movement of lithium ions. This undesired effect prevents the resulting solid-state battery to achieve its theoretical performances and needs to be avoided. The first model is an adaptation of the work of J. M. Hu et alii [1] for a similar interface problem encountered between yttria-stabilized zirconia electrolytes (YSZ) and lanthanum-strontium-manganite cathodes (LSM) in solid oxide fuelcells (SOFC), while the second is based on the work of D. A. Cogswell [2][3] for phase separation in metal alloys, extended to include electrostatic effects due to internal charge unbalances and externally applied electric fields. Animplementation of the latter is however lacking, and the interested reader is encouraged to build one up on the theoretical framework presented in this paper. In the conclusion section it is possible to find insights on how to prevent the interfacial diffusion between LCO and LLZO with reference to experimental attempts and simulations, as well as future directions for the development of the models.

The global oil refining industry with its present product distribution essentially shifted towards fuels such as gasoline and diesel will most likely hold the fort for considerable time. However, conditions are changing and refinery survival will very much depend on long-term planning, process and product flexibility and being at the frontiers of refining technology, a technology where catalysts play leading roles. Today oil refiners are faced with the challenge of producing fuels that meet increasingly tight environmental specifications, in particular with respect to maximum sulphur content. At the same time, the average quality of crude oil is becoming poorer with higher amounts of aromatics, heteroatoms (sulphur and nitrogen) and heavy metals. In order to stay competitive, it is of decisive importance for refiners to upgrade dense petroleum fractions of low quality to highly value-added products. A practicable route, for example, is upgrading the catalytic cracking by-product Light Cycle Oil (LCO) into a high-quality diesel-blending component in a two-step catalytic process. In the first step the LCO is hydrotreated over a Pt Pd based acidic catalyst bringing about heteroatom and aromatic reduction and isomerization of C6 to C5 naphthenic structures. In the second step these naphthenic structures are selectively opened over an Ir-based catalyst to improve the cetane value. The present thesis is mainly devoted to the second catalytic step of LCO upgrading and was partly conducted within the framework of the European Union project RESCATS. From the patent literature it is evident that iridium-based catalysts could be good candidates for ring-opening purposes. A literature survey covering ring opening of naphthenic structures made in the beginning of the project (in 2001), showed the need for extending investigations to heavier hydrocarbons, more representative of the diesel fraction than model compounds such as alkylated mono C5 and C6 naphthenic rings frequently employed in previous academic studies. Ring-opening catalysts, mainly Pt-Ir based, were synthesised at KTH by two different techniques: the microemulsion and the incipient wetness techniques. Paper I is a review of the microemulsion technique and its applications in heterogeneous catalysis. Characterization of catalysts was performed employing a multitude of techniques including quantitative TPR, TEM-EDX, XPS, CO FT-IR, NH3-DRIFTS and XRF etc. Catalytic screening at 325 oC and atmospheric pressure with hydrogen and pure indan as model substance was conducted to investigate ring-opening activity in terms of conversion and selectivity to desired cetane-boosting products. This development process is the topic of Papers II-IV. The possible industrial implementation of the best catalyst candidate is demonstrated in Paper V. When designing a catalytic system aimed at refining petroleum, it is crucial to monitor the evolution of the sulphur distribution throughout the different stages of the process so that catalyst properties and reaction parameters may be optimised. The final section of this thesis and Paper VI are devoted to high-resolution sulphur-distribution analysis by means of a sulphur chemiluminescence detector (SCD) following gas chromatographic separation. / QC 20101014

Une nouvelle méthodologie de modélisation cinétique des procédés de raffinage traitant les charges lourdes a été développée. Elle modélise, au niveau moléculaire, la composition de la charge et les réactions mises en œuvre dans le procédé.La composition de la charge est modélisée à travers un mélange de molécules dont les propriétés sont proches de celles de la charge. Le mélange de molécules est généré par une méthode de reconstruction moléculaire en deux étapes. Dans la première étape, les molécules sont créées par assemblage de blocs structuraux de manière stochastique. Dans la deuxième étape, les fractions molaires sont ajustées en maximisant un critère d'entropie d'information.Le procédé de raffinage est ensuite simulé en appliquant, réaction par réaction, ses principales transformations sur le mélange de molécules, à l'aide d'un algorithme de Monte Carlo.Cette méthodologie est appliquée à deux cas particuliers : l'hydrotraitement de gazoles et l'hydroconversion de résidus sous vide (RSV). Pour le premier cas, les propriétés globales de l'effluent sont bien prédites, ainsi que certaines propriétés moléculaires qui ne sont pas accessibles dans les modèles traditionnels. Pour l'hydroconversion de RSV, dont la structure moléculaire est nettement plus complexe, la conversion des coupes lourdes est correctement reproduite. Par contre, la prédiction des rendements en coupes légères et de la performance en désulfuration est moins précise. Pour les améliorer, il faut d'une part inclure de nouvelles réactions d'ouverture de cycle et d'autre part mieux représenter la charge en tenant compte des informations moléculaires issues des analyses des coupes de l'effluent.