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National @ ENERGIE+FRM; International audience; Thermodynamics is routinely used as a tool to determine favourable reaction conditions so that high yields into products of interest can be achieved. It is yet far less common to relate the proportions of reactants and products present in a reactor to thermodynamic equilibrium constants pertaining to the system to unravel the details of the reaction mechanism. Earlier examples dealing with alkane hydroisomerisation, methanol steam reforming and selective NOx reduction will be recalled emphasising the power of this approach, which is then applied to the condensation of ethanol to butanol. The so-called Guerbet reaction enables converting ethanol, a renewable feedstock, into higher alcohols. Important conclusions regarding the design of ethanol condensation processes will be drawn, as the main reaction mechanism occurring at high temperatures (ca. 350-420°C) appears to be different from that proposed at low temperatures (

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International @ ENERGIE+SBE:AAU; International audience; Cellobiose (a disaccharide derived from the condensation of two glucose molecules linked by a ß(1?4) bond) can be obtained by enzymatic or acid inorganic hydrolysis of cellulose and cellulose rich materials. The difficulties connected to cellobiose hydrolysis are due to strong-inter- and intra-molecular hydrogen bonds which are formed from the eight free alcohol (COH) groups and three ether linkages of the cellobiose molecule. Only catalysts with strong protonic acidity (Brönsted sites) are suitable for this reaction. Moreover, when the heterogeneous catalytic reaction occurs in water, the catalyst has to maintain its acidity even in this protic and polar solvent which is known to quench the acidity of many good solid acids. A series of WOx/ZrO2 samples with various tungsten oxide loadings (1–20) wt.% was prepared by co-precipitation and their surface properties characterized in particular by NH3 adsorption microcalorimetry to determine the number and strength of acid sites. Concerning the acid site nature, a progressive increase of the amount of Brřnsted sites with the WO3 loading was observed. The catalytic reaction of cellobiose disaccharide hydrolysis showed a better catalytic performance on the highest WO3 loaded catalysts, associated to the presence of Zr-stabilized WOx clusters and a strong protonic acidity.

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International @ ENERGIE+AJH:SBE:AAU; International audience; Nowadays, several researches are investigating the possibility to store thermo-chemically the heat produced by renewable energies [1] for various applications. In order to increase the stored energy density, new composite materials should be developed. Often these materials are composed of a host material and a hygroscopic salt [2]. This combination can double the heat storage properties by optimizing the water sorption–desorption cycles [3]. In this work, porous silica-alumina powders with different quantities of alumina were selected, impregnated with 10 wt. % of calcium chloride and tested as heat storage materials. Composite materials were prepared by incipient wetness impregnation of commercial silica-alumina powders (containing respectively 13, 25 or 75 wt.% of alumina) with calcium chloride and labelled as S13ACa, S25ACa, and S75ACa. The composite materials were calcined at 260°C and their surface area was measured by means of N2 adsorption at -196°C. The heats of water sorption-desorption on the silica-alumina composites were determined using a Setaram TG-DSC 111 apparatus. Moreover, successive cycles of hydration (at 20°C) / dehydration (at 150 °C) were performed to check the cyclability of the system. The hydration / dehydration cycles and the corresponding recorded heats for the three porous silica-alumina powders and their composites are reported in the figure. The S75A sample provides the lower heat per gram of material if compared to S13A and S25A. We can observe that the heat released per gram of material decreases by increasing the Al2O3/SiO2 ratio. Once the calcium chloride is deposited on the silica-alumina powders, the quantity of generated heat increased with respect to the corresponding bare silica-alumina support. The S13ACa composite shows the highest heat released during the hydration step (457 J.g-1 of material) compared to S25ACa and S75ACa composites (342 and 274 J.g-1 of material respectively). In conclusion we can observe that to obtain good thermal energy storage materials, both the Al2O3/SiO2 ratio and the salt hydrates deposition have to be optimized. More composites with tuned AlO3/SiO2 ratio and different types and concentration of salt hydrates are under study; the systematic adjustment of the composites composition is pursued starting from the feed-back data obtained by TG-DSC analysis. [1] J. Jänchen, D. Ackermann, H. Stach, W. Brosicke, Solar Energy, 76 (2004) 339 [2] E.A. Levitskij, Yu.I. Aristov, M.M. Tokarev, V.N. Parmon, Solar Energy Materials and Solar Cells, 44 (1996) 235. [3] I.A. Simonova, A. Freni, G. Restuccia, Yu.I. Aristov, Microporous and Mesoporous Materials, 122 (2009) 223-228.

International @ ENERGIE+EML:SBE:AAU; International audience; Thermal solar energy storage is an interesting way of reducing gas emissions. This storage can be achieved using water vapour absorption-desorption in binary or ternary systems with a desiccant salt like lithium bromide, lithium chloride, zinc bromide, zinc chloride, etc. As illustrated in the figure below, in summer, solar energy dehydrates a concentrated solution of salt in the generator. The water vapour is condensed and stored in the water tank. The resulting more concentrated solution is stored in a semi crystallized form in a second tank. In winter, the previous condensed water is evaporated at low temperature, using geothermal source, and absorbed by the highly concentrated salt solution in the absorber, thus generating thermal energy. A previous successful work [1] was realised using lithium bromide as absorbent. In spite of its good thermal properties, its high price prevented it from use in the industrial process. Therefore, i n order to design the most powerful system, it is important to determine its thermal behaviour compared to LiBr. In this work, dissolution enthalpies of various anhydrous salts (LiBr, LiCl, ZnCl2, ZnBr2, KOH, NaOH, KCHO2 and KC2H3O2) were determined. The experiments were performed by titration calorimetry at 25°C. The plot of cumulated enthalpies versus coefficient a= n_salt/n_solute allowed determining the dissolution and dilution enthalpies [2]. According to this study, zinc bromide presents the highest dissolution enthalpy. Nevertheless, literature data indicates a low activity coefficient of ZnBr2 in water which implies a weak ability of water absorption. Moreover, in the binary system ZnBr2/H2O, zinc hydroxide can be created and could gravitate in pipes. In order to improve the efficiency of a system comprising ZnBr2, this salt was associated to the previously cited anhydrous salt, in water or mixed solvents such as alcohol-water. Dissolution and dilution enthalpies at various ratios of salts of this new system were determined like previously. Furthermore, measurement of the vapour pressure above concentrated solution indicated the rate of water absorption and allowed determine the most suitable system for the process. [1] K.E. N’Tsoukpoe, N. Le Pierrčs, L. Luo, Energy 37 (2012) 346-358 [2] M.H. Hamedi, B. Laurent, J-P.E. Grolier, Thermochim. Acta 445 (2006) 70-74

International @ ENERGIE+AAU:SBE:OOT; International audience; Hierarchical zeolites, a novel type of zeolites containing two levels of porosity (i.e. micropores and mesopores) have been investigated in recent years [1,2,3]. In this work, a postsynthetic route for mesopore formation via alkaline treatment was applied to FAU, BEA and MFI type zeolites. The main focus of the study was to evaluate the influence of this procedure on the acidity of the zeolites. Parent zeolites were obtained from Zeolyst International: FAU (CBV 760, SiO2/Al2O3=60), BEA (CP814E, SiO2/Al2O3=25) and ZSM-5 (CBV 5524G, SiO2/Al2O3=50). Mesopore formation was performed using alkaline treatment, following the procedures reported in literature [4,5]. Samples were characterized by low temperature nitrogen adsorption, X ray diffraction and solid-state 27Al MAS NMR. Acidity of parent and mesoporous samples was estimated through the adsorption of typical probe molecules - measurements were conducted in both gas phase (microcalorimetry/volumetry of ammonia adsorption, FTIR spectrometry of pyridine adsorption/desorption) and liquid phase (calorimetry/volumetry of phenylethylamine adsorption). The obtained results revealed different degrees of acidity preservation in the mesoporous samples, compared to the parent ones, within the three investigated zeolitic structures. No significant changes in total acidity were detected for ZSM-5, while FAU and BEA zeolites seem to be more sensitive to the alkaline treatment. FTIR of pyridine adsorption/desorption revealed that the largest decrease in acidity as a whole could be attributed to Bronsted acidity diminishing. Different information on acidity changes were obtained by the adsorption of probes from gas or liquid phase. These differences express the different surface conditions in the experiments, giving a more complete view of the sample’s acidity and the possibility to correlate them to zeolites’ catalytic and adsorptive properties in either gas or liquid phase.

National @ ENERGIE+EML:SBE:AAU; International audience; Le potentiel de l’énergie solaire comme énergie renouvelable a été largement démontré depuis plusieurs années. Le stockage inter-saisonnier de cette énergie peut ętre réalisé au moyen d’un nouveau procédé basé sur l’absorption de la vapeur d’eau par une solution saline. Le choix du sel utilisé comme absorbant doit répondre ŕ différents critčres : une stabilité chimique, un bon transfert thermique et une forte capacité d’absorption de la vapeur d’eau. Ce dernier paramčtre est caractérisé par une faible pression de vapeur au-dessus de la solution saline saturée ce qui traduit un faible coefficient d’activité de l’eau dans la solution et une bonne solubilité du sel dans l’eau. Une précédente étude [1] a été réalisée en utilisant le bromure de lithium (LiBr) comme absorbant avec des rendements thermiques trčs encourageants. En revanche, son prix élevé ne permet pas d’envisager son uti lisation dans un procédé industriel. Pour cette raison six nouveaux sels ont été sélectionnés dans cette étude en fonction de leur forte solubilité dans l’eau et leur faible coűt : le chlorure de zinc (ZnCl2), le bromure de zinc (ZnBr2), le formate (KCHO2) et l’acétate de potassium (KC2H3O2), l’hydroxyde de potassium (KOH) et l’hydroxyde de sodium (NaOH). Afin d’évaluer le comportement thermique des sels, leurs enthalpies de dissolution ont été déterminées ŕ 25°C ŕ forte et faible concentrations dans l’eau. Ces expériences ont été réalisées par titration calorimétrique par ajouts successifs d’eau sur les sels anhydres. Ainsi, chaque addition d’eau permet d’obtenir l’enthalpie intégrale de dissolution en fonction de la molalité. La représentation graphique de ces enthalpies cumulées en fonction d’un coefficient a défini par a= n(eau)/n(sel) permet de déterminer les enthalpies de dissolution et de dilution [2]. Les résulta ts obtenus ont été comparés ŕ ceux de LiBr. [1] K.E. N’Tsoukpoe, N. Le Pierrčs, L. Luo, Energy 37 (2012) 346-358 [2] M.H. Hamedi, B. Laurent, J-P.E. Grolier, Thermochimica Acta 445 (2006) 70-74

National @ ENERGIE+AJH:SBE:AAU; International audience; Le stockage ŕ sorption de vapeur d’eau par un matériau composite offre une capacité de stockage de chaleur thermique importante ŕ long terme [1] par rapport aux autres technologies de stockage existantes telles que le stockage par chaleurs sensible, latente ou chimique [2]. Le stockage thermochimique (ŕ sorption d’eau), qui se fait habituellement par le biais de composés ŕ base d’une matrice poreuse et d'un sel hygroscopique [3], se caractérise par une alliance entre la chimisorption et la physisorption. L’objectif de ce travail consiste ŕ élaborer de nouveaux composites qui présentent une densité de stockage élevée avec une capacité de sorption optimale pour le stockage inter-saisonnier de chaleur. Entre différents matériaux poreux, la silice alumine a été sélectionnée comme support d’imprégnation par des quantités variables de chlorure de calcium, d’hydroxyde de baryum et de nitrate de lithium. Les composites ont été testés en mesurant leurs chaleurs de sorption-désorption de la vapeur d'eau respectivement entre 20 et 150°C en utilisant un appareil TG-DSC. Les chaleurs de sorption/désorption de la vapeur d’eau ont été mesurées pour la silice-alumine (SA) et les composites contenant en masse 10% de CaCl2 (SA10Ca), Ba(OH)2 (SA10Ba) et LiNO3 (SA10Li). La relation entre la taille des pores et la capacité de sorption des composites a été étudiée. Différentes techniques ont été utilisées afin de caractériser les matériaux composites du point de vue structural et textural (BET, DRX,…). La figure 1 montre que le composite contenant 10% massique de Ba(OH)2 fournit la chaleur la plus importante lors de l'hydratation /déshydrations (51 kJ.mol-1H2O) par comparaison avec la chaleur dégagée par les échantillons SA10Ca et le SA10Li (40 et 41 kJ.mol-1H2O respectivement). La quantité de la chaleur dégagée par mole d’eau par les composites SA10Ba est supérieure ŕ celle dégagée par SA10Ca et SA10Li. En revanche, ŕ cause de sa faible capacité de sorption d’eau, la chaleur stockée par unité de matériau reste faible. Le composite SA10Ca se révčle ętre le plus prometteur grâce ŕ sa haute valeur de chaleur dégagée et son faible coűt. Références [1] J. Jänchen, D. Ackermann, H. Stach, W. Brosicke, Studies of the water adsorption on zeolites and modified mesoporous materials for seasonal storage of solar heat Solar Energy, 76 (1-3) (2004), pp. 339–344. [2] S.M. Hasnain, Review on sustainable thermal energy storage technologies, Part I: heat storage materials and techniques, Energy Conversion and Management, 39(1-11)(1998), pp. 1127-1138. [3] E.A. Levitskij, Yu.I. Aristov, M.M. Tokarev, V.N. Parmon, A new approach to accumulating low potential heat, Solar Energy Materials and Solar Cells, 44 (1-3) (1996), pp. 219-235.

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National @ ENERGIE+EML:SBE:AAU; International audience; Thermal solar energy storage is an interesting way of reducing gas emissions. This storage can be achieved using water vapour absorption-desorption in a binary or ternary system with a desiccant salt-like lithium bromide, lithium chloride, calcium chloride, etc. As illustrated in the figure below, in summer, solar energy dehydrates a concentrated solution of salt in the generator. The water vapour is condensed and stored in the water tank. The resulting more concentrated solution is stored in a semi crystallized form in a second tank. In winter, the previous condensed water is evaporated at low temperature, using geothermal source, and absorbed by the highly concentrated salt solution in the absorber, thus generating thermal energy. Therefore, in order to design the most adaptable system for this process, it is important to determine its thermal behaviour. In this work, dissolution and dilution enthalpies and solubilities were studied for five anhydrous salts (lithium chloride, lithium bromide, zinc bromide, zinc chloride and sodium thiocyanate) by titration calorimetry. Experiments were carried out at different temperatures from 25°C to 40°C. On one hand, the plot of cumulated enthalpy versus coefficient ą= n_salt/n_solute allows determining the dissolution and dilution enthalpies. One the other hand, these experiments allow to calculate the salt solubility and its kinetics for each temperature. The results have been compared to theoretical data. Moreover, salt hydration characteristics were studied. Indeed, the concentrated solution is crystallized in the tank to increase the storage density and reduce the storage tank size. Therefore, the salt should crystallize in anhydrous or at least in monohydrated form. The five anhydrous salts were hydrated at room temperature. They were analysed using thermogravimetry (TG) and differential scanning calorimetry (DSC) to determine the transition temperature of the hydrated form and its corresponding dehydration enthalpy.

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International @ +DST:SBE:AAU; International audience; Glycerol is currently produced in waste quantities as a byproduct from the production of biodiesel. It is normally generated at the rate of 1 mol of glycerol for every 3 mol of methyl esters synthesized; approximately 10 wt% of total product. Therefore, to make the biodiesel sector sustainable and more profitable all of the produced glycerol should be efficiently processed. Promising route for glycerol valorization is its catalytic dehydration to acetol and/or acrolein. In this work acid-base properties of zirconia based, titania based and calcium phosphate catalysts were fully characterized by adsorption calorimetry and FTIR spectroscopy of appropriate probe molecules. Catalytic behavior of studied materials was tested in the gas phase dehydration of glycerol. Special attention is given to the correlation between catalytic activity and surface acid–base properties, which are essential to the mechanism of the reaction.

International @ ENERGIE+AJH:SBE:AAU; International audience; KEYWORDS: Heat storage, Composite materials, Porous matrix, Hydrate of salts The energy challenge imposed by exhaustion of fossil fuels and their increasing consumption has favoured the emergence of optimal energy management based on the use of alternative resources such as solar energy. Sustainable development of the contemporary society requires exploring a new clean technology for production and storage of energy. The household sector is the main consumer of energy. A large part of this energy is consumed by heating systems. Therefore, good management of household thermal comfort implies the decrease in consumption of this energy, while indoor temperature stays the same. This can be achieved through the use of thermo-chemical energy storage technology. Thermo-chemical storage materials offer heath storage capacities of long time periods. Several researches have investigated possibilities of thermo-chemical heat storage [1] and of their applications. However, in order to increase the stored energy density, new composite materials should be developed and characterized. These materials are usually composed from the combination of a host material and a hygroscopic salt. This kind of composite material makes a powerful system where the type of storage is twice enhanced: firstly the porous matrix is used to release and store heat through the sorption-desorption cycles of water vapor, secondly, salt hydrates are used to release and store energy by chemical reaction of sorption-desorption. The most challenging task in development of such materials is the choice of porous host materials which could contain salt hydrates [2] and thus allow to get a higher sorption heat. In this work, in order to develop a new composite material safe, cheap and presenting a high energy density with an optimal sorption capacity for seasonal heat storage, several porous host materials such as silica gel, silica alumina gel, activated carbon, alumina, bentonite and aerosil were tested for their heats of sorption-desorption of water vapor by using a TG-DSC apparatus. From the presented results (Fig. 1), it is easy to see that the silica alumina gel, silica gel and alumina achieved the highest heats of hydration/dehydration (60, 53 and 52 kJ.mol-1 of H2O respectively) compared to those of bentonite, activated carbon and aerosil (26, 16 and 15 kJ.mol-1 of H2O respectively). The choice of the hygroscopic salt hydrates depends on many selection criteria [3] such as their low price, weak environmental footprint and reversible heat of water vapor sorption during their hydration/dehydration reaction but also on improving their structural stability during thermal cycling. Fig.1: TG-DSC analysis of the heat of hydration/dehydration using different materials. For this aim, eleven salt hydrates were selected to impregnate the host materials and tested during hydration-dehydration. The sorption heats were determined by using a C80 calorimeter (SETARAM), the cell being flushed by a water vapor saturated gas flow of helium. Research work on storing heat has resulted in the development of innovative materials developed specifically for this application. Various techniques have been carried out to characterize the materials in their surface and bulk properties by BET and XRD respectively. References: [1] Stach, H., Mugele, J., Jänchen, J. & Weiler, E. Adsorption 11, Boston(2005); 393-404. [2]L.G. Gordeeva, Y.I. Aristov, Carbon Techn(2012); 1-15. [3]Sharma SD, Sagara K. International Journal of Green Energy( 2005);2:1–56.

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International @ ENERGIE+SBE:EML:AJH:AAU; International audience; The energy challenge imposed by exhaustion of fossil fuels and their increasing consumption has favoured the emergence of optimal energy management based on the use of intermittent energies produced starting from alternative resources such as solar, wind and geothermic energies. The problem to solve for the efficient use of these clean and renewable energies remains their storage and transportation. In the present work, three different research subjects based on storage and transportation of renewable energies are described. 1- In the first application the solar energy is applied to the building heating systems domain, where a good management of household thermal comfort nowadays implies the decrease in consumption of energy, while maintaining the same indoor temperature. This can be achieved through the use of thermo-chemical energy storage technology. Salt hydrates and their composites (obtained by incorporating the salt hydrates into a highly porous host matrix) have shown great potential as thermochemical heat storage materials. They can be utilized in applications such as providing heating in homes during winter (exothermic hydration of the solid material) by discharging the stored (solar) energy gained during the summer months (endothermic dehydration of the solid). For this aim, several composites were tested during hydration-dehydration in a TG-DSC apparatus. 2- The second application implies the combined use of solar and geothermic energies for house heating systems. In summer the thermal solar energy storage is achieved using water vapour absorption-desorption in binary or ternary systems with a desiccant salt like lithium bromide, lithium chloride, zinc bromide, zinc chloride, etc. The water vapour is condensed and stored in the water tank. The resulting more concentrated solution is stored in a semi crystallized form in a second tank. In winter, the previous condensed water is evaporated at low temperature, using geothermal source, and absorbed by the highly concentrated salt solution in the absorber, thus generating thermal energy. In this work, dissolution and dilution enthalpies of various anhydrous salts were determined by titration calorimetry. 3- The development of solid-state hydrogen storage materials with enhanced performances and improved safety is a key point for the commercialization of hydrogen as energy carrier. Mg hydride is one of the most promising materials for hydrogen storage. MgH2 presents low cost, high hydrogen capacity, light weight, abundance, excellent reversibility, and it is relatively safe to handle. To overcome the kinetic limitation and thermodynamic stability of MgH2, the addition of various activators has been tested by performing Pressure-Composition-Isotherm (PCI) experiments at different temperatures and temperature-programmed-desorption (TPD) measurements. Looking at the obtained results we can state that calorimetry and thermal analysis are necessary techniques in the renewable energy research field and that further developments and applications of these tools have to be expected in the very near future.

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National @ ENERGIE+AJH; International audience; Abstract Samples of mannitol aqueous solution at various contents of dissolved oxygen were frozen with the help of ultrasounds and the ice crystals size distributions were measured by optical microscopy. Increasing the content in oxygen led to a fair decreasing of the average crystals size and an increasing of the homogeneity of the size of crystals within the sample. The average size appeared simply as inversely proportional to the oxygen content in the initial liquid solution. Keywords : ultrasounds, ice crystals, size distribution

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