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Re´sume´-Purification des gaz de synthe`se -Les proce´de´s de synthe`se de biocarburants par voie Fischer-Tropsch (FT), voies B-XTL, repre´sentent des alternatives prometteuses pour la production d'e´nergie. Ces proce´de´s permettent la conversion en carburants de synthe`se de biomasse lignocellulosique, e´ventuellement mise en oeuvre en me´lange avec des charges fossiles telles que petcoke, charbons ou re´sidus sous vide. Pour ce faire, une e´tape de gaze´ification convertit la charge carbone´e en un gaz de synthe`se (me´lange de CO et H 2 ), lequel, apre`s ajustement du ratio H 2 /CO et e´limination du CO 2 , subit ensuite la re´action de FischerTropsch. Les gaz de synthe`se contiennent cependant de nombreuses impurete´s qui ne´cessitent d'eˆtre e´limine´es afin d'e´viter l'empoisonnement des catalyseurs Fischer-Tropsch. En raison de la grande varie´te´de charges pouvant eˆtre mises en oeuvre, la composition des gaz de synthe`se est susceptible de subir d'importantes variations, en particulier de part la nature des impurete´s (e´le´ments, spe´ciation) pre´sentes ainsi que leurs teneurs relatives. La composition des gaz de synthe`se est e´galement soumise a`des spe´cifications extreˆmement se´ve`res en terme de purete´lie´es a`l'importante sensibilite´aux poisons des catalyseurs FT. Pour ces raisons, la purification des gaz de synthe`se constitue un de´fi majeur pour le de´veloppement des proce´de´s B-XTL. Dans cet article, nous pre´sentons les principaux enjeux lie´s a`la purification des gaz de synthe`se. Les diffe´rents types d'impurete´s pouvant eˆtre pre´sentes dans les gaz de synthe`se sont pre´sente´es. L'influence de la nature de la charge, des technologies de gaze´ification ainsi que des conditions ope´ratoires associe´es sur la nature des impurete´s et leurs teneurs relatives est discute´e. Une attention particulie`re est porte´e au devenir des compose´s soufre´s, azote´s, des haloge`nes, me´taux lourds et me´taux de transition. Les principales technologies de purification des gaz de synthe`se (adsorption, absorption, re´actions catalytiques, etc.) sont finalement de´crites, ainsi que les de´fis associe´s.Abstract -Synthesis Gas Purification -Fischer-Tropsch (FT) based B-XTL processes are attractive alternatives for future energy production. These processes aim at converting lignocellulosic biomass possibly in co-processing with petcoke, coal, or vacuum residues into synthetic biofuels. A gasification step converts the feed into a synthesis gas (CO and H 2 mixture), which undergoes the Fischer-Tropsch reaction after H 2 /CO ratio adjustment and CO 2 removal. However synthesis gas also contains various impurities that must be removed in order to prevent Fischer-Tropsch catalyst poisoning. Oil & Gas Science and Technology -Rev. IFP Energies nouvelles, Vol. 68 (2013), No. 4, pp. 707-723 Copyright Ó 2013, IFP Energies nouvelles DOI: 10.2516 Due to the large feedstocks variety that can be processed, significant variations of the composition of the synthesis gas are expected. Especially, this affects the ...

The heterometallic complex [Bi(2)Pd(2)(O(2)CCF(3))(10)(HO(2)CCF(3))(2)] (1) was obtained by the solid state reaction of Bi(III) trifluoroacetate/trifluoroacetic acid adduct with unsolvated trinuclear Pd(II) trifluoroacetate. The crystal structure of 1 consists of discrete tetranuclear molecules, in which two paddlewheel [BiPd(O(2)CCF(3))(4)] units are connected by two chelating-bridging trifluoroacetate ligands through bismuth ends. There are no metal-metal bonds in the tetrameric structure of 1, since both Bi...Pd (3.0843(4) A) and Bi...Bi (4.5074(4) A) distances are too long to be considered as bonding interactions. A study of the solution behavior revealed that not only the coordinated trifluoroacetic acid in 1 can be effectively replaced by other donor solvent molecules but also the tetranuclear complex can be cleaved in solution into discrete dinuclear Bi-Pd species. Complex 1 was used as precursor for the preparation of a bimetallic Pd-Bi carbon-supported catalyst. The preparation procedure included the modification of the carbon support to increase the number of oxygenated functions at its surface followed by grafting complex 1 via ligand exchange for surface carboxylates and activating thermally. The resulting catalyst, consisting of small supported metallic particles, was found to be more active than the reference materials prepared from multisource homometallic Pd and Bi precursors.

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