International audienceSolar thermal energy represents an increasingly attractive renewable source.However,to provide continuous availability of this energy,it must be stored. This paper presents the state of the art on high temperature(573-1273K)solar thermal energy storage based on chemical reactions,which seems to be the most advantageous one for long-term storage. The paper summarizes the numerical,experimental and technological studies done so far. Each system is described and the advantages and drawbacks of each reaction couple are considered

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19Bio-additives obtained from the acetylation of biodiesel-derived glycerol has been 20 extensively synthesized because of their nature as value-added products and their 21 contribution to environmental sustainability. Glycerol acetylation with acetic acid produces 22 commercially important fuel additives. Considering that the recovery of individual 23 monoacetin, diacetin (DA), and triacetin (TA) is complicated, many endeavors have 24 enhanced the selectivity and total conversion of glycerol using acetic acid during catalytic 25 acetylation. In this work, we extensively review the catalytic activity of different 26 heterogeneous acid catalysts and their important roles in glycerol acetylation and product 27 selectivity. In addition, the most influential operating conditions to attain high yield of 28 combined DA and TA are achieved by closely examining the process. This review also 29 highlights the prospective market, research gaps, and future direction of catalytic glycerol 30 acetylation.31 3anhydride is not manufacturing-friendliness especially for large-scale production (as above 47 49 °C explosive vapour/air mixtures may be formed). 48On the contrary, the sudden decline in crude oil prices has significantly reduced the 49 prices of biodiesel during the second half of 2014. Figure 1(a) shows the biodiesel prices 50 declined strongly from 112 USD/hL (2013) to less than 80 USD/hL (2014); the ten-year 51 forecast for biodiesel prices are expected to recover in nominal terms close to those in 2014 52 level (prices vary from 85-90 USD/hL). Figure 1(b) indicates that the global biodiesel 53 production is expected to reach almost 39 billion liters by 2024; moreover, the projected 54 production volume of biodiesel is stable and is mostly policy driven 3 . Nevertheless, 55 conversion of biodiesel-derived glycerol into value-added products is necessary to support 56 long-term growth of the oleochemical market. The price reported for 80% pure crude glycerol 57 is $0.24/kg and that for United States Pharmacopeia (USP)-grade glycerol is $0.9/kg in mid-58 2014 4 . 59 Various studies on transforming glycerol into different value-added derivatives, such 60 as propylene glycerol, polyglycerols, succinic acid, gaseous hydrogen, glycerol carbonate, 61 acrolein, fuel additives, ethanol, glycerol esters, and lubricant additive, were conducted 5-12 . 62 This review aims to study the role of heterogeneous acid catalysts in glycerol acetylation 63 using acetic acid given that the low selectivity of the desired products (diacetin (DA) and 64 triacetin (TA)) remains the greatest challenge in catalytic acetylation. In addition, recovery of 65 key derivatives is a very complicated work because the mono-, di-, and tri-substituted 66 derivatives that constitute a mixture exhibit indistinguishable boiling points 1 . This review 67 then focuses on the important features of solid acid catalysts and on the influence of 68 operating parameters in enhancing the product selectivity of glycerol acetylation. To our best 69 knowledge, this work i...

Solilltkln \'•rilobb Cam:crcritlo.molsl>vcrol Céll\Cefll'll.ioncild«trol)'II: pllor'"'tloemtJI) / I! a Glycerol is a by product produced from biodiesel, fatty acid, soap and bioethanol industries. Today, the value of glycerol is decreasing in the global market due to glycerol surplus, which primarily resulted from the speedy expansion of biodiesel producers around the world. Numerous studies have proposed ways of managing and treating glycerol, as well as converting it into value added compounds. The electrochem ical conversion method is preferred for this transformation due to its simplicity and hence, it is discussed in detail. Additionally, the factors that could affect the process mechanisms and products distribution in the electrochemical process, including electrodes materials, pH of electrolyte, applied potential, current density, temperature and additives are also thoroughly explained. Value added compounds that can be produced from the electrochemical conversion of glycerol include glyceraldehyde, dihydroxyacetone, gly colic acid, glyceric acid, lactic acid, 1 :i. propanediol, 1,3 propanediol, tartronic acid and mesoxalic acid. These compounds are found to have broad applications in cosmetics, pharmaceutical, food and polymer industries are also described. This review will be devoted to a comprehensive overview of the current sce nario in the glycerol electrochemical conversion, the factors affecting the mechanism pathways, reaction rates, product selectivity and yield. Possible outcomes obtained from the process and their benefits to the industries are discussed. The utilization of solid acid catalysts as additives for future studies is also suggested

OATAO is an open access repository that collects the work of Toulouse researchers and makes it freely available over the web where possible. This is an author-deposited version published in : http://oatao.univ-toulouse.fr/ Eprints ID : 15980To link to this article : Michel Ca(OH)2/CaO reversible reaction in a fluidized bed reactor for thermochemical heat storage. AbstractThermal energy storage (TES) is a key factor for increasing the efficiency of concentrated solar power plants. TES using a reversible chemical reaction appears to be a promising technology for high energy density thermal storage (100-500 kW h m À3 ), at high temperature (up to 1000°C) and during a long period (24 h to several months). This paper details an experimental study to carry out the reversible reaction Ca(OH) 2(s) + DH r () CaO (s) + H 2 O (g) in a fluidized bed (FB) reactor. The 4 lm Ca(OH) 2 powder fluidization has been performed with an appropriate proportion of inert easy-to-fluidize particles. Then, Ca(OH) 2 dehydration and CaO hydration have been implemented in a FB reactor and 50 cycles have been reached. The mean energy density obtained is 60 kW h m À3 solid_mixture which amounts to a promising energy density of 156 kW h m À3 Ca(OH) 2 -bulk if the reactants and the easy-to-fluidize particles are separated. The results demonstrated the feasibility of the implementation of the Ca(OH) 2 /CaO thermochemical heat storage in a fluidized bed reactor.

Glycerol electrooxidation has attracted immense attention due to the economic advantage it could add to biodiesel production. One of the significant challenges for the industrial development of glycerol electrooxidation process is the search for a suitable electrocatalyst that is sustainable, cost effective, and tolerant to carbonaceous species, results in high performance, and is capable of replacing the conventional Pt/C catalyst. We review suitable, sustainable, and inexpensive alternative electrocatalysts with enhanced activity, selectivity, and durability, ensuring the economic viability of the glycerol electrooxidation process. The alternatives discussed here include Pd-based, Au-based, Ni-based, and Ag-based catalysts, as well as the combination of two or three of these metals. Also discussed here are the prospective materials that are yet to be explored for glycerol oxidation but are reported to be bifunctional (being capable of both anodic and cathodic reaction). These include heteroatom-doped metal-free electrocatalysts, which are carbon materials doped with one or two heteroatoms (N, B, S, P, F, I, Br, Cl), and heteroatom-doped nonprecious transition metals. Rational design of these materials can produce electrocatalysts with activity comparable to that of Pt/C catalysts. The takeaway from this review is that it provides an insight into further study and engineering applications on the efficient and cost-effective conversion of glycerol to value-added chemicals.

A laminar-flow tubular crystallizer was used for seedless continuous flow crystallization of an active pharmaceutical ingredient, namely, Brivaracetam, which has a polymorphic behavior: rod-shaped crystals and a pseudo-polymorphic solvated, needle-like crystal. The combination of fast cooling at 20 °C/s and high supersaturation values between 4 and 11 resulted in the discrimination of nucleation and growth of only the desired crystalline form even though its solubility curve is very close to the one of the undesired needle shape. Crystal nucleation and the start of crystal growth occur inside the tubular crystallizer; high flow rates prevent clogging of the crystallizer. Further crystal growth may be, if desired, stopped via immediate filtration. In this way, an industrially applicable continuous crystallizer is proposed. It is also demonstrated that the presence of restrictions in the tubing drastically increases the nucleation rate. A literature survey points out that induced turbulence can occur under current flow conditions using said restrictions.

The condensation reaction of furfural (F) on acetone (Ac) gives a high added value product, the 4-(2-furyl)-3-buten-2-one (FAc), used as aroma in alcohol free drinks, ice, candies, gelatines and other products of current life. This synthesis valorises the residues of sugar cane treatment since furfural is obtained by hydrolysis of sugar cane bagasse followed by vapor training extraction. In the face of numerous and complex reactions involved in this synthesis, it is very complicated to define the kinetic laws from exact stoichiometry. A solution allowing to cope the problem consists in identifying an appropriate stoichiometric model. It does not attempt to represent exactly all the reaction mechanisms, but proposes a mathematical support to integrate available knowledge on the transformation. The aim of this work is the determination of stoichiometric and kinetic models of the condensation reaction of furfural on acetone. Concentrations of reagents and products are determined by gas and liquid chromatography. Concentration profiles obtained at different temperatures are used to identify kinetic parameters. The model is then used for the optimization of the production of FAc. The interest of such tool is also shown for the scale up of laboratory reactor to a large scale. The anticipation of the reaction behaviour in large scale is crucial especially when the reactor presents important limitations of thermal exchange capacity.