Gerhard PirngruberIFP Energies nouvelles · Catalysis and Separation Division
Gerhard Pirngruber
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September 2006 - present
September 2000 - September 2005
September 2000 - September 2005
Publications
Publications (138)
We carried out a mechanistic investigation of the dehydration of fructose catalyzed by a series of proton‐exchanged faujasite zeolites. Using a combination of analytical tools (HPLC, GC, NMR), we could solve and quantify most of the variety of products formed, including (i) cyclic intermediates (ii) transient species (monomeric and dimeric) (iii) b...
The Brønsted acidity of proton-exchanged zeolites has historically led to the most impactful applications of these materials in heterogeneous catalysis, mainly in the fields of transformations of hydrocarbons and oxygenates. Unravelling the mechanisms at the atomic scale of these transformations has been the object of tremendous efforts in the last...
Hydroisomerization and hydrocracking of octylcyclohexane (C14H28) were performed over Pt and NiMoS‐supported catalysts, at 300 °C and 60 bar, with a molar H2 to hydrocarbon ratio of 7 mol/mol. The feed, composed of 5 wt.% phenyloctane dissolved in n‐heptane, was initially hydrogenated in situ over a pre‐catalyst, Pt or NiMoS/Al2O3. The C14 naphthen...
In this work, we propose to evaluate and validate an emerging spectroscopic space-resolved technique: atomic force microscopy coupled with infrared spectroscopy (AFM-IR) for inorganic materials in tapping mode at the nanoscale. For this aim, a preliminary investigation of sample preparation techniques was done and the stability of tapping AFM-IR sp...
This paper is a part of a study on reactivity descriptors in vacuum gas oil hydrotreatment (VGO HDT). It aims to understand the differences in feeds of various process origins and the corresponding hydrotreated effluents on a molecular level. Four different vacuum gas oils were hydrotreated over a sulfided NiMo/Al2O3 catalyst at a wide range of tem...
Environmental regulations concerning fuel‐related sulfur emissions are currently experiencing worldwide expansion. This is motivating the research and development of improved hydrotreating (HDT) catalysts with carefully engineered synthesis methods that maximize activity as ultimate goal. In this contribution, the effect of phosphorus doping and tr...
Photocatalytic processes are regarded as a sustainable and environmental-friendly way to attenuate mankind’s strong dependence on fossil fuels, which is the main responsable for high pollution levels in our planet. Metal microporous chalcogenides, due to band structure, bandgap value and highly reduced charge carrier’s residence time within the cry...
A representative accelerated experimental deactivation procedure was developed to understand the activity loss of bifunctional vacuum gasoil (VGO) hydrocracking catalysts over time. Experiments were performed in an up-flow fixed-bed pilot unit with a typical vacuum gas oil feedstock. The deactivation was measured by tracking the decrease of VGO con...
γ-Al2O3 is a transition alumina oxide used in many different applications. Its surface chemistry seems to be a key factor in the preparation of heterogeneous catalyst where γ-Al2O3 is used as a support. The modification and description of its surface are necessary to understand the role of the support on the catalyst preparation and on its performa...
Hydroconversion of perhydrophenanthrene was performed over Pt/Beta and Pt/ASA bifunctional catalysts and compared to results obtained on Pt/USY zeolite catalyst, under the same operating conditions. Perhydrophenanthrene resulted from hydrogenation of...
The current environmental and industrial contexts require constant revision and improvement of hydrotreating processes for obtaining cleaner (bio)fuels through the development of supported transition metal sulfide (TMS) catalysts. The present work proposes a surface-science approach to describe the surface-dependent genesis of the cobalt-promoted a...
Requirements for improved catalytic formulations is continuously driving research in hydrotreating (HDT) catalysis for biomass upgrading and heteroatom removal for cleaner fuels. The present work proposes a surface‐science approach for the understanding of the genesis of the active (sulfide) phase in model P‐doped MoS2 hydrotreating catalysts suppo...
The industrial use of zeolites for adsorptive and separative applications at a mature level has been generalized in the last decades. Thanks to the advantages associated with the usual higher reversibility of the adsorption process, improved energy efficiencies can be obtained leading to a consolidated alternative to the traditional separation tech...
Most industrial hydrocracking catalysts contain metal sulfides. It is commonly accepted that sulfide-based bifunctional hydrocracking catalysts are less well balanced than Pt-based catalysts, because of their weak (de)hydrogenation activity. However, the difference in catalytic performances between the two catalysts has never been quantified. In th...
The Front Cover shows some of the reaction intermediates involved in the conversion of a tricyclic naphtene, perhydrophenanthrene, over a bifunctional Pt/faujasite (USY) catalyst. In their Full Paper, L. Brito et al. analyze the reaction pathways, which first lead to isomerization products, then to ring‐opening and finally to cracking products. A d...
Mesostructured titania as support for the CoMoS active phase in deep hydrodesulfurization (HDS) of 4,6-dimethydibenzothiophene (4,6-DMDBT) leads to an increase of the intrinsic HDS activity and a higher selectivity for direct desulfurization (DDS) for HDS reaction in contrast with the conventional CoMoS/alumina catalyst. The temperature treatment o...
In petroleum refining, middle distillates are produced via hydroisomerization/hydrocracking processes using bifunctional catalysts often containing ultrastable Y (USY) zeolite. Petroleum fractions serving as feedstock for hydrocracking processes contain a majority of (poly)cyclic hydrocarbon molecules. Few studies on reaction mechanisms of hydrocra...
This paper aims to understand the reactivity of different nitrogen species during the catalytic hydrodenitrogenation (HDN) of a mixture of straight-run gas oil and coker gas oil. Effluents at different HDN conversions were analyzed by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR/MS), with ElectroSpray Ionization (ESI). Positi...
Two NiMo sulfide catalysts, supported on Al2O3 and silica-alumina, respectively, were compared in the hydrotreating of a mixture of straight-run and coker gasoil. Experiments were conducted in a continuous fixed bed reactor, at 623-643K and 5 MPa. The Al2O3-supported catalyst proved to be slightly more active in HDN and significantly more active in...
In order to meet the demand for cleaner fuels, it is necessary to develop high performing hydrotreating catalysts. Although organic additives are often used to improve the performances of hydrotreating catalysts, bio-polymer additives have not yet been thoroughly investigated. We recently showed that dopamine, a neurotransmitter molecule, which is...
In silico screening of CO2 adsorbents is a very powerful method for pre-selecting the most promising porous solids for experimental studies. Due to the increasing computational power, it is now possible to screen a large number of adsorbents in a fairly short time. However, it remains difficult to rationalize structure-performance correlations beca...
Organic additives are widely used in order to improve the performance of hydrotreating catalysts. Yet, the use of polymers, in particular bio-polymers, is less widespread. We present, herein, a strategy to coat alumina support with a bio-polymer, namely polydopamine (Pdop). The Pdop coated supports provide a higher number of adsorption sites for Mo...
The constant improvement of hydrotreating (HDT) catalysts, driven by industrial and environmental needs, requires a better understanding of the interactions between the oxide support (mostly alumina) and the MoS2 active phase. Hence, this work addresses the support-dependent genesis of MoS2 on four planar single-crystal α-Al2O3 surfaces with differ...
A detailed kinetic study of the hydrodenitrogenation (HDN) network of quinoline was carried out over Ni-promoted MoS2 catalysts supported either on γ-Al2O3 or on amorphous silica alumina (ASA), the objective is to identify the role of the support acidity in HDN reactions. The kinetic data obtained from catalytic tests in a batch reactor were analyz...
Process models are a vital tool for the development of industrial hydrocracking units and to drive innovation of process design and novel catalysts. A hydrocracking model, based on the continuous lumping approach, is presented in this work. A zeolite catalyst was used for hydrocracking of pre-treated VGO feeds. The model includes inhibition terms f...
The role of the oxide support on the structure of the MoS2 active phase (size, morphology, orientation, sulfidation rate…) remains an open question in hydrotreating catalysis and biomass processing with important industrial implications for the design of improved catalytic formulations. The present work builds on an aqueous-phase surface science ap...
A kinetic study of the hydrodenitrogenation of quinoline is performed in a batch reactor, over a NiMo(P)/γ-Al2O3 sulfide catalyst, in the range of temperature of 340-360 °C and concentration of 1-2 wt % of quinoline. Liquid-vapor mass transfer is considered in the reactor model, and the kinetic expression using Langmuir-Hinshelwood model considers...
New developments and breakthroughs in the design of hydrotreating (HDT) catalysts for complying with fuel specifications and reduced sulfur contents ask for a continuous improvement in the molecular scale description of the active phase both at the oxide and sulfide states. HDT catalysts are mainly based on alumina-supported molybdenum nanophases a...
The choice of an appropriate adsorbent for CO2 separation by pressure-swing adsorption remains a field of intense research. In this work, several FAU and LTA zeolites with different Na contents (Si/Al ratios) are studied for the separation of CO2 from mixtures of CO2, CO, and CH4 by means of breakthrough experiments. The breakthrough experiments we...
Pressure swing adsorption (PSA) is a promising method for an economically viable separation of CO2 from gas mixtures. One important step in developing efficient PSA separations is to choose an adsorbent with a good compromise between selectivity and working capacity. The problem can be seen as an optimization process where one searches the properti...
Vapor–liquid equilibrium (VLE) data for hydrogen/hydrocarbon mixtures based on real feedstocks at high temperature and pressure is scarce and is needed to model hydrocracking systems accurately. Experiments with a vacuum gas oil have been used to generate VLE data for real hydrogen/hydrocarbon mixtures under hydrocracking conditions in a semibatch...
We propose a method for analytically predicting single component adsorption isotherms from molecular, microscopic and structural descriptors of the adsorbate - adsorbent system and concepts of statistical thermodynamics. Expressions of the Henry constant and the heat of adsorption at zero coverage are derived. These functions depend on the pore siz...
The present work describes the adsorption and separation of xylene isomers by ZIF-8. Although the formal pore diameter of ZIF-8 is much smaller than the molecular diameter of the xylene isomers, ZIF-8 is able to separate the isomers by molecular sieving. A structural study indicates that the diffusion of the xylenes into the pore structure of ZIF-8...
CO2 capture processes based on dry solid sorbents have been praised as a very attractive alternative to absorption by amine solvents (in particular monoethanolamine) in terms of energy consumption. The present paper critically analyzes these very optimistic predictions. It presents a theoretical analysis of three different temperature swing adsorpt...
The adsorption processes for postcombustion CO2 capture are usually based on a temperature or vacuum swing (TSA or VSA). In the present contribution an alternative concept is presented, which is based on the regeneration of the solid sorbent (an immobilized amine) by a purge gas, low pressure vapor, under almost isothermal conditions. Because of th...
The confinement effect plays a key role in physisorption in microporous materials and many other systems. Confinement is related to the relationship between the pore geometry (pore size and topology) and the geometry of the adsorbed molecule. Geometric properties of the porous solid can be described using the concepts of Gaussian and mean curvature...
A zeolite beta–silicalite-1 composite was prepared by growing polycrystalline silicalite-1 shells on single micron-sized zeolite beta crystals. The obtained core–shell material was employed for the separation of hexane isomers. Gravimetric uptake measurements revealed that the silicalite-1 shell acted as a membrane that controlled the transport to...
Simulation results in the literature suggest that Vacuum Swing Adsorption (VSA) processes using physisorbents might largely outperform the current state-of-the-art post-combustion CO2 capture technologies based on amine solvents in terms of energy consumption. Most studies consider the zeolite NaX as adsorbent. NaX has a very strong affinity for CO...
A systematic study of the effect of coordinatively unsaturated sites (cus) in the separation of CO2/CH4 and CO/CO2/CH4 mixtures on CPO-27-M (M = Ni, Co, and Zn) and STA-12-Ni metal–organic frameworks was carried out using gravimetric and breakthrough experiments. The separation selectivity and the working capacity of these structures were evaluated...
The separation of xylene isomers is one of the most difficult separations in petrochemistry. Adsorbents have to preferentially adsorb para or meta isomers, but there are only a few zeolites which fulfill the criteria of selectivity and adsorption capacity. In this study, we evaluate two metal–organic frameworks (MOF) with coordinatively unsaturated...
Current European regulations limit the sulfur content of gasoline to 10 ppmw. Such deep desulfurization levels can be achieved by catalytic hydrodesulfurization processes, but they are accompanied by excessive H2 consumption for unwanted side reactions, in particular, for the hydrogenation of olefins. Selective adsorption constitutes an attractive...
The crystal chemistry of divalent metal N,N′-piperazinebis(methylenephosphonates) of the STA-12 family, (M2(H2O)2(O3PCH2NC4H8NCH2PO3)·xH2O, M = Mg, Mn, Fe, Co, Ni) is compared. The different metal analogues are isostructural in the hydrated forms, possessing R3¯ symmetry, but their reversible dehydration behaviour and resultant porosity are strongl...
ZIF-76, Zn(Im)x(5-ClbIm)y (Im = imidazolate, 5-ClbIm = 5-chlorobenzimidazolate), is, among the known ZIF structures, one of the few materials that combine a relatively large pore aperture with a large pore volume. Moreover, it is thermally stable up to 400 °C and can be stored under ambient atmosphere without undergoing a measurable degradation. ZI...
This work reports the adsorption and coadsorption data of CO(2)/CH(4)/CO mixtures on several metal-organic frameworks [MOFs; MIL-100(Cr), MIL-47(V), MIL-140(Zr)-A, Cu-btc, and MIL-53(Cr)] and compares them with reference adsorbents, that is, zeolite NaX and an activated carbon material, AC35. We also evaluate the effect of H(2)O on CO(2) adsorption...
The separation of paraffin isomers is a very important topic in the petrochemical industry. Zeolite 5A is industrially used to sieve alkane isomers, but its pore size does not allow the separation of monobranched and dibranched alkanes by a kinetic mechanism. In this publication, we compare three ZIF materials in the separation of C6-paraffin isome...
The objective of this work was to study the adsorption and separation of the most important families of hydrocarbon compounds on metal-organic frameworks (MOFs), in comparison with zeolites. For this purpose, we have selected four probe molecules, each of them representing one of these families, i.e., o- and p-xylene as aromatics, 1-octene as an al...
Carbon dioxide is the main undesirable compound present in raw natural gas and biogas. Physisorption based adsorption processes such as pressure swing adsorption (PSA) are one of the solutions to selectively adsorb CO(2) from CH(4). Some hybrid crystalline porous materials that belong to the family of metal-organic frameworks (MOFs) show larger CO(...
Adsorption properties of linear and branched (C5–C9) alkanes were studied on the mesoporous materials MCM-41, MCM-48, PHTS and SBA-15 in the 75–195 °C temperature range. Adsorption enthalpies at zero coverage and Henry constants were measured by gas phase chromatography. The experimental data was statistically investigated and used for modeling. Qu...
The current state-of-the-art post-combustion capture technology is absorption of CO2 by an aqueous monoethanolamine (MEA) solution. MEA has a very strong affinity to CO2 and captures CO2 efficiently even at low partial pressure, but the regeneration of the solvent by heating requires a large amount of energy. Moreover, degradation of the amine by o...
The invention relates to a FAU-type zeolite membrane that comprises a FAU-type zeolite crystal layer incorporated in the surface porosity of at least one selected face of a porous substrate, in which the ratio between the thickness of said zeolite layer incorporated in the surface porosity of said selected face of the substrate and the total thickn...
Introduction – Zeolites and mesoporous materials are widely used as catalysts or separating agents in the refining and petrochemical industries. The understanding of adsorption phenomena is critical in the comprehension and the modeling of reaction kinetics. Selectivity and adsorption efficiency are often characterized by Henry constants and adsorp...
Multivariate Data Analysis and Modeling techniques (e.g. PCA, PLS) have been applied to the adsorption data for a set of linear and branched alkanes in the C5-C9 region at zero coverage on mixed mesoporous and microporous silica materials (MCM-41, MCM-48, PHTS, SBA-15) and Metal-Organic-Frameworks (MOFs; e.g. MIL-47, Amino-MIL-53) to obtain predict...
This article describes a novel application of high-throughput experimentation, namely in the field of liquid mixture separation through adsorption. Two separate setups are designed and extensively used to study multicomponent liquid phase adsorption: the first setup performs batch adsorption in static conditions to obtain adsorption isotherms while...
This paper presents the application of a new machine learning approach called Graph Machines to the prediction of the adsorption enthalpies of linear and branched alkanes on various zeolites. In this approach, the molecules are considered as structured data and are represented by graphs. For each individual of the data set, a mathematical function...
A purely electrostatic picture predicts that small, more polarizing cations adsorb more strongly than the large ones. In the case of the adsorption of CO(2) on faujasite Y, however, the inverse order is found at low pressure: CsY and KY adsorb stronger than NaY and LiY. This trend cannot be explained by a simple monopole-dipole or monopole-quadrupo...
Statistical data analysis was applied to examine adsorption properties of linear and branched alkanes on mesoporous materials (MCM 41, MCM 48, PHTS, SBA-15). The objective was to establish predictive models that could qualitatively and quantitatively describe the adsorption enthalpies and Henry constants in the gas phase. Partial least square regre...
Molecular simulations have shown that the metal−organic framework Cu-BTC (Cu3(BTC)2) is an interesting candidate for the separation of CO2 by adsorption. In this work, the first experimental binary and ternary adsorption data of CO2, CH4, and CO on the Cu-BTC are reported. These data are analyzed and compared with coadsorption models that are built...
Statistical data analysis was applied to examine previously published adsorption enthalpies of linear and branched alkanes on zeolites Na-Y, Na-USY, Mordenite, Beta, ZSM-5 and ZSM-22. The objective was to establish predictive models that correlate the adsorption enthalpies for the six zeolites to simple structural properties or descriptors of the a...
Microporous ordered carbon have been synthesized by the nanocasting process from zeolite Y using acetylene and furfuryl alcohol as carbon precursors. If the proper synthesis conditions are chosen, these materials retain the long-range order of the zeolite mold. The resulting carbons possess a large surface area (≥2200 m2/g), a high microporosity (≥...
Statistical data analysis was applied to examine adsorption properties of linear and branched alkanes on mesoporous materials (MCM-41, MCM-48, PHTS, SBA-15) and zeolite ZSM-57. Predictive models were established that can quantitatively describe the adsorption enthalpies and Henry constants in the gas phase. Partial least square regression was perfo...
This chapter collects the available information about the nature of surface oxygen species in iron and copper zeolites and explains the fascinating chemistry of these materials. Transition-metal cations, which are embedded in a zeolite host matrix, do not have the same catalytic properties as the corresponding transition-metal oxides. Iron- and cop...
Experimental measurements and molecular simulations were conducted for two zeolitic imidazolate frameworks, ZIF-8 and ZIF-76. The transferability of the force field was tested by comparing molecular simulation results of gas adsorption with experimental data available in the literature for other ZIF materials (ZIF-69). Owing to the good agreement o...
Nanocomposite MFI-alumina and FAU-alumina Membranes: Synthesis, Characterization and Application to Paraffin Separation and CO2 Capture - In this work, we report the preparation of thermally and mechanically resistant high-surface (24-cm(2)) nanocomposite MFI-alumina and FAU-alumina membranes by pore-plugging synthesis inside the macropores of alph...
The present study attempts to understand the use of the flexible porous chromium terephthalate Cr(OH)(O(2)C-C(6)H(4)-CO(2)) denoted MIL-53(Cr) (MIL = Material from Institut Lavoisier) for the separation of mixtures of CO(2) and CH(4) at ambient temperature. The coadsorption of CO(2) and CH(4) was studied by a variety of different techniques. In sit...
Details of the synthesis of the small-pore silicoaluminophosphate (SAPO) molecular sieves STA-7 (SAV) and STA-14 (KFI) prepared via a co-templating approach are described. STA-7 includes Si in the framework with Si/(Si+Al+P) ratios varying from 0.04 to 0.17, whereas STA-14 crystallizes from gels with a narrower compositional range (Si/(Si+Al+P) = 0...
The active core of the enzyme methane mono-oxygenase (MMO) contains an iron (or copper) dimer with histidine and glutamic acid ligands located on a His-x-x-Glu sequence of the peptide chain. We mimicked the active core of MMO by immobilising the His-Gly-Gly-Glu motif on a silica support, using the methods of solid phase peptide synthesis, and by al...
This study reports the preparation of a FAU-type membrane for the separation of CO2/N2. The membrane is prepared by in situ seeding followed by a two-step secondary growth to plug the 0.2 μm macropores of a multilayer α-Al2O3 tube. The key factor for successful in situ seeding is the infiltration of the synthesis mixture in the pores of the α-Al2O3...