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The conversion of biogas into ethane and ethylene is an actual alternative to conventional petrochemicals paths. The oxidative coupling of methane (OCM) has been intensively studied these last decades. While optimized catalyst formulation can achieve promising C2 selectivity from CH4, the direct use of biogas, a CH4 + CO2 mixture, has not been studied. Most studies on OCM have used catalyst in powder form, whereas supported catalysts, necessary in any industrial process, have hardly been addressed. We investigated the miniaturization of a string pellet reactor configuration to a single extrudate using a Mn-Na-W/Al2O3 catalyst for the kinetic study of the OCM reaction.

CoMoS/γ-Al2O3 catalysts for FCC gasoline hydrodesulfurization (HDS) have been studied extensively during the past decades. These catalysts allow decreasing the content of sulfur compounds while avoiding olefin hydrogenation (HYD) to maintain a high-octane number [1,2]. Although a morphology−selectivity relationship and kinetic studies have been reported, [3] no detailed kinetic models that fully describe the product distribution are available. Moreover, all reactivity/selectivity studies were performed under steady-state conditions, which do not allow discriminating between rival models [4]. Consequently, there is a lack of information about reaction pathways in HDS processes. To develop a more detailed reaction mechanism based on elementary steps, transient kinetic experimentation has been explored for HDS and HYD competitive reactions over catalysts with variable contents of active phase together with microkinetic modeling, complementary to steady-state studies.A series of catalysts with variable Co/Mo atomic ratios and a constant density of molybdenum (dMo = 2.2 at.nm-2) has been prepared on γ-Al2O3 support. The increase of cobalt amount allows to form a greater quantity of the most active CoMoS phase without significant changes in slab length or stacking [5]. In this case, the influence of the active phase amount on catalytic performances can be studied independently of the morphology effect.Step experiments under atmospheric pressure were carried out by switching the feedstock from the mixture of 2,3-dimethylbut-2-ene (23DMB2N) in n-heptane to the mixture of 3-methylthiophene (3MT) and 23DMB2N in n-heptane by means of a 4-way valve. The time-dependent effluent compositions were analyzed by an online mass spectrometer and a gas chromatograph with flame ionization detection. This double analysis simultaneously permitted a fast analysis of the reactants and H2S and the determination of the full product distribution.A lower steady-state rate of olefin hydrogenation was observed in the presence of 3MT. This kind of inhibition has already been observed in the literature and attributed to the strong adsorption of H2S and 3MT [1]. The ratio of the HDS / HYD conversions at 1 bar increases with Co/Mo atomic ratio and reaches a plateau at Co/Mo=0.3 (Fig. 1a). For high throughput experiments at 15 bar over the same catalysts, a similar trend is observed with the maximum at Co/Mo=0.4. Firstly, promotion by Co takes place on the S-edge up to the full Co promotion at Co/Mo=0.3. The HDS reaction is considered to be more favorable on promoted S-edge in comparison with HYD. For higher Co/Mo values, S-edge is completely promoted, and Co atoms are placed on M-edge, which is not selective for HDS reaction [1].Despite similar trends in Fig. 1a, a large gap in ratio of the HDS / HYD conversions is observed for 1 bar and 15 bar. Both HDS and HYD reactions are favoured at high pressure and at 1 bar while no 3-methyltetrahydrothiophene as intermediate was observed. Moreover, the ratio of C5 olefins to C5 paraffins is always higher for experiments at 1 bar.To interpret the transient data, a microkinetic model was developed to elucidate the reaction mechanism and to better understand selectivity over CoMoS catalysts. A large set of parameters is required for modeling of the transient responses. Therefore, some parameters of the elementary steps were obtained from steady-state data over similar catalysts. The initial model correctly describes the evolutions of 3MT, 23DMB2N and all products for a given Co/Mo ratio. The transient responses change significantly with changing Co/Mo ratio (Fig. 1b). Microkinetic modeling indicates that especially 3MT adsorption and H2S formation are impacted by the Co/Mo ratio. These parameters were adjusted to adequately fit the 3MT transient responses.References[1] Toulhoat, H., Raybaud, P., “Catalysis by transition metal sulphides”, Editions Technip, 2013.[2] Brunet, S., Mey, D., Pérot, G., Bouchy, C., Dielh F., Appl. Catal. A: General 278 (2005).[3] Baubet, B., Girleanu, M., Gay, A.-S., Taleb, A.-L., Moreaud, M., Walh, F., Delattre, V., Devers, E., Hugon, A., Ersen, O., Afanasiev, P., Raybaud, P., ACS Catal. 6 (2016).[4] Berger, R.J., et al., Appl. Catal. A: General 342 (2008).[5] Gandubert, A.D., Legens, C., Guillaume, D., Rebours, S., Payen, E., OGST – Rev. IFP, 62 (2007).

Fossil fuel demand is continuously increasing, particularly in the field of transport, where light petroleum products and middle distillate products are used. The transformation of the heavy oil cuts into middle distillate fuel is essential to meet current and future demand for fuels. The most widely consumed products, such as diesel, can be produced by hydrocracking reactions [1]. On the other hand, the development of new generations of non-fossil fuels, such as biomass derivatives, is of great interest [2]. Co-processing VGO (Vacuum Gas Oil) with bio-oil has been investigated in a few studies [3]. The aim of this work is to shed light on the impact of bio-liquids on the hydrocracking reactions with mineral feed into middle distillates. We studied various bioliquids coming from wood biomass having undergone different treatments like stabilized pyrolysis oil (SPO) or hydrothermal liquefaction (HTL). The study evaluates, in a semi-batch reactor under hydrogen pressure, the performance of sulfide catalysts in the presence of a bio-liquid-VGO (Vacuum Gas Oil) mixture.

To fulfil climate objectives, the production of synthetic e-fuels using CO2 as a raw material appears as part of the solution. In particular, Power-to-Liquid (PtL) concept is combining CO2 with hydrogen supplied from water electrolysis, powered by renewable sources, is currently gaining interest as it allows the production of sustainable fossil-free liquid fuels. The proposed process discussed here is an upgrading of the well-known Fischer-Tropsch synthesis. The concept deals with two cascade reactions in one pot with first the conversion of CO2 into CO via the Reverse Water Gas Shift (RWGS) reaction, which is then followed by the Fischer-Tropsch Synthesis (FTS). Instead of using a Fe-based catalyst, which can carry out both reactions, we have chosen the strategy to decouple the two functions (RWGS and FT) on two different catalysts within the same reactor. The FTS shall shift the equilibrium of the RWGS reaction (which alone would be limited to 15-20% of conversion at 250°C) by converting the CO into hydrocarbons. This strategy shall enable optimization of the catalyst pair and thus lower the temperature of reaction thanks to the equilibrium shift to gain selectivity in the liquid fraction. The challenge lies in maximizing the activity of the RWGS catalyst, but also in the ability of the FT catalyst to be highly selective. Methane production is the main concern as the energetic barrier of CH4 formation is generally lower than that of the RWGS reaction, so the goal will be to minimize methane selectivity.

MICROSCOPIE:RX+ING+TEG:ATU:LBU:FBS:YSC:FRM; National audience; The direct decomposition of NOx at moderate temperatures is a challenge over noble metal based catalysts because of the poisoning of the metal surface by oxygen. Au is inactive for NO direct decomposition, but displays oxidation resistance. The objective of this work is to obtain durable activity for NO direct decomposition by combining inert Au with an active metal such as Pd, which is known to deactivate. Pd-Au/SiO2 nanoparticles were prepared using a surface redox method. TEM-EDX analyses showed that most particles (3-24 nm in size) contained both metals, though the composition was not homogeneous. In situ XRPD analyses initially displayed poorly crystalline Au, Pd and possibly a Pd-Au alloy phase. Calcination in air yielded PdO and a Au-rich alloy phase, whose composition (Au0.8Pd0.2) seems to be the limiting composition under oxidizing conditions. Under H2, β-PdHx (at 25°C) or metallic Pd (with a thermal expansion at 450°C) were obtained besides Pd-rich alloyed phases. After removing H2 pressure, PdHx decomposed into metallic Pd. The Au-modification of the parent Pd/SiO2 yielded a stable activity. The post-reaction XRPD pattern showed a significant fraction of metallic Pd and alloyed phases in addition to PdO.

SSCI-VIDE+CATREN:ING+WDR:NOG:DLA:YSC; International audience; An alternative to reduce fossil fuels dependency without heavy investment on new refineries is co-processing bio-oils derived from lignocellulosic biomass with conventional fossil feedstocks. However, the integration of bio-oil in this process faces some technical difficulties such as their high oxygen content, low miscibility with hydrocarbon fuels, low chemical stability and high acidity [1]. Therefore, it is necessary to improve bio-oil quality before using it to produce fuels. One possible option to upgrade the bio-oil quality is to produce it in an integrated catalytic pyrolyser, where the biomass conversion is carried out in the presence of an heterogeneous catalyst, such as ZSM-5 [2]. However, zeolites are susceptible to the deactivation, impacting on operational costs of process and reducing its competitiveness compared with fuel production from exclusively fossil feedstocks [3]. As an alternative for traditional catalysts, metal oxides can show acidic characteristics and good resistance to coke formation. Among them, niobium-based oxides has been studied for heterogeneous catalysis [4], but it has not been widely explored for upgrading of pyrolysis vapors. Thus, the aim of this work was to evaluate the impact of different niobium-based metal mixed oxides on the conversion of wood pyrolysis vapors employing an ex-situ catalytic system. These mixed oxides with different acidities were compared to a reference catalyst (ZSM-5). Three catalysts based on niobium oxide doped with another metal oxide (W, Al or Mn) were prepared and characterized. Pyrolysis of beech wood chips and catalytic conversion of the vapors were carried out in a laboratory-scale fixed-bed reactor equipped with a semi-continuous biomass dispenser. The gas phase was analyzed on-line using a µGC. The organic and aqueous phases of condensed bio-oil were separated by centrifugation. The organic phase was characterized by Karl-Fischer titration, elemental analysis (CHNS), GC-MS and 13C-NMR.Promising results were obtained for the treatment of pyrolysis vapors. One of the prepared catalysts exhibited equivalent catalytic performances, when compared to ZSM-5, in terms of liquid phase selectivity and reduction of oxygen content in the organic phase, which is directly related to the reduction of compounds that results in instability and immiscibility for bio-oils with traditional oil feedstocks. Modifications are planned to improve the activity of these metal-mixed oxides.Acknowledgements: This project has received funding from the European Unions’ Horizon 2020 research & innovation programme under grant agreement N° 818120. References[1]Md. M. Rahman, R. Liu, and J. Cai, Fuel Processing Technology 180, 32 (2018).[2]G. Yildiz et al., Renewable and Sustainable Energy Reviews 57, 1596 (2016).[3]A. V. Bridgwater, Biomass and Bioenergy 38, 68 (2012).[4]P. Yang et al., Applied Catalysis B: Environmental 239, 114 (2018).

RX+ING+TEG:FRM:ATU:YSC:FBS; International audience; NOx direct decomposition over noble metals is thermodynamically favored and does not require reducing agents. However, the challenge is the poisoning of the noble metal surface by oxygen. On the other hand, Au is inactive for NO direct decomposition, but is one of the metals most resistant against oxidation. Our objective is to obtain a durable catalyst for NO direct decomposition by combining inert Au with an active metal such as Pd, which deactivates when used alone. Silica-supported Pd, Au and Pd-Au nanoparticles were prepared using earlier recipes. TEM-EDX analysis of the bimetallic sample showed that most of the particles contained both metals. In situ XRD analyses carried out at various temperatures under H2 evidenced the formation of Pd-Au alloyed phases. Alloyed phases were also present and stable under air at 500 °C, though Pd content decreased. The direct decomposition of NO to N2 and N2O was studied at 450°C. Au/SiO2 is inactive. Interestingly, the Pd-Au was more active than the parent Pd sample. Pd-Au also exhibited a stable activity with time, in contrast to the parent Pd material. Detailed product analyses showed that O release was higher for the Pd-Au catalyst, confirming that Au prevented Pd deactivation by facilitating O desorption.

SSCI-VIDE+ING+CMI:ATU:DFA:YSC; International audience; None

SSCI-VIDE+ECI2D:ING+MLU:EGI:FRM:CMI:EPU:YSC:NOG; International audience; Nickel supported on Mg-Al oxides was studied in the autothermal reforming (ATR) of model biogas at 700 degrees C. Ni/Mg0.4Al2O3.4 deactivated with time on stream and the cause of deactivation was investigated and identified. Ni was readily oxidized to NiO in the presence of O-2. While NiO was essentially inactive for the reforming reaction, this oxide was yet active for methane combustion. Exhaustion of the O-2 supply at front of the catalyst bed enabled the remaining CH4 to be steam and dry reformed on the metallic Ni left downstream. Gradual formation of NiAl2O4 spinel was also observed, likely caused by the higher temperature prevailing in the exothermic combustion zone that favors the diffusion of nickel cations into the alumina structure. In contrast to NiO, NiAl2O4 spinel was poorly active for CH4 oxidation. The frontline associated with the formation of the NiAl2O4 spinel phase eventually reached the end of the catalyst bed, resulting in a complete loss of activity. No significant coke deposition could be evidenced here. The Ni deactivation profile was adequately fitted using a methane ATR kinetic model that included a linear decrease in the number of Ni metallic sites. Addition of Rh/Mg1.1Al2O4.1 in front of a nickel-based catalyst led to a stable activity. Using this dual-bed system, no NiAl2O4 formation was identified after reaction. (C) 2016 Elsevier B.V. All rights reserved.

SSCI-VIDE+ING+CMI:YSC:DFA; International audience; None

SSCI-VIDE+ING+YCP:CMI:YSC; International audience; The conversion of the huge EU potential of unrecycled organic wastes and residues to gasoline, diesel or kerosene could contribute up to 16% of the present demand in transportation fuels. Among these various industrial wastes, black liquors (BL), generated from paper and pulp Kraft process might represent a relevant option with a stable production of around 30 Mt/y (dry organic) which might lead to ca 7 M tons of transportation fuels. 3 A number of scenarios can be designed to concatenate the elemental steps of waste-to-fuel processes. The value chain selected here describes a stepwise upgrading of raw BLs: i) hydrothermal liquefaction (HTL), ii) removal of troublesome alkaline and sulfur residues, iii) hydrogenation (HDO) for oxygen removal and decrease of molar weight and finally iv) co-processing with crude oil distillates (vacuum gas oil, VGO) by catalytic cracking (FCC) to produce second generation transportation biofuels.As for the HTL of black liquor to produce a readily separable oil-like product, i.e. biocrude, it is shown that up to 75% of the BL’s energy content can be extracted as an oil-like product under suitable process conditions. Parameters like reaction temperature and time, catalyst type (e.g., NaOH, NaCO3, Ca(OH)2), and effect of additives (e.g., guaiacol, glycerol) on key physical properties like viscosity have been tested and optimized.For the HDO step, experiments were carried out in water as slurry medium, testing various catalysts selected on HDO model compounds and catalyst-to-biocrude ratios as well as biocrude concentrations. It was found possible to liquefy up to 55 wt.% based on dry organic matter of biocrude. Despite a still high viscosity due to the high averaged molecular weight (ca 2074 g/mol), an oxygen content of about 12 % has been reached as a target for further co-processing.Lab-scale Micro Activity Test (MAT) experiments simulating FCC process were carried out to co-process the upgraded BL with VGO over equilibrated FCC catalysts, targeting at gasoline hybrid fuels of standard yields and quality. For a 1/9 fossil/bio feedstock ratio, it was observed a slight increase in naphtha yields with more olefins and aromatics due to hydrogen transfer from hydrocarbons to oxygenates during cracking, with a slight increase in coke formation due to depleted medium in hydrogen. A global assessment of all these trends confirm the interest of such a biowaste-to-biofuels scenario, which remains to be proved at demonstration scale. This is planned to be done within a new running EU contract which targets demonstration of co-processing from various upgraded biogenic wastes, including HTL treated black liquors4.

SSCI-VIDE+ECI2D:ING+YSC:FRM:NOG:DLR; International audience; Effect of Sn on the adsorption of H₂ and the production of methanol during syngas conversion over Co/alumina.

XPS+ING+YSC:FRM:LCS; International audience; Unexpected role of CO acting as an oxidizer over Pt-Sn nanoalloys.

SSCI-VIDE+ING+NOG:DBI:YSC; International audience; Biogas is formed by anaerobic digestion of biomass and contains essentially methane and carbon dioxide. It can be reformed into syngas over Ni-based catalysts, for hydrogen production or for Fischer-Tropsch synthesis. However, the CO2/CH4 ratio in biogas is generally

SSCI-VIDE+ECI2D:ING+DLR:YSC:CMI; International audience; A major barrier in the commercialization of biomass gasification into bio-syngas is the presence of impurities such as NH3, HCl, H2S, tars and alkali in the products since they are detrimental to downstream processes like the conversion of bio-syngas to substitute natural gas (SNG). The exact role and the effects of these biomass-derived impurities on methanation catalysts are not clearly documented, especially when such aging (or promoting) factors can combine with structural aging processes such as metal sintering under operating conditions . In the present study, we report the way to control/limit these aging processes over industrial Ni based catalysts, following up our previous investigation of model biogas impurities such as ammonia and acetonitrile for N containing compounds, heptane, toluene and benzene as tar representatives, iii) trichloroethylene for Cl containing compounds, all combined with metal particle sintering occurring under SNG process conditions .

SSCI-VIDE+ING+FRM:NOG:YSC; International audience; Hydrocarbons are the main reaction products of syngas conversion over cobalt-based catalysts. Methanol is also produced as a minor by-product and has been proposed to be produced via a specific reaction pathway involving formates species located at the interface with the support [1]. The poisoning of a Co/alumina catalyst with Sn was studied here and a stronger decline in methanol production was observed at higher Sn/Co ratios, similarly to the case of hydrocarbons reported earlier [2] .The addition of Sn did not prevent the formation of formates as observed by operando diffuse reflectance FT-IR spectroscopy. The reactivity of these formates measured during a chemical transient was yet markedly lowered in the presence of Sn. In addition, the presence of tin dramatically reduced the adsorption of H2 onto the catalyst. These observations can be rationalized according to the following model. Firstly, Sn poisoned sites on the cobalt nanoparticles, hindering H2 adsorption and activation, thereby limiting the subsequent hydrogenation of formates to methanol. Secondly, Sn addition could also have specifically poisoned interfacial sites, where the most reactive formates were present.These observations provide a wider understanding of the various hydrogenation pathways of CO taking place over cobalt-based catalysts.Reference:[1] D. Lorito, A. Paredes-Nunez, C. Mirodatos, Y. Schuurman, F.C. Meunier, Catal. Today, 259 (2015) 192–196. [2] A. Paredes-Nunez, D. Lorito, L. Burel, D. Motta-Meira, G. Agostini, N. Guilhaume, Y. Schuurman, F.C. Meunier, Ang. Chem. Int. Ed. 57 (2018) 547-550.