Albert Germain

Nafion-layered silicate nanocomposite membrane for fuel cell application

Abstract Direct methanol fuel cells (DMFCs) using a proton exchange membrane as electrolyte is an attractive option for electricity generation. The most widely used membrane in the DMFC system is based on a perfluorinated polymer bearing sulfonic acid functions like Nafion ®. The latter combines chemical, mechanical and thermal stability and high protonic conductivity but shows elevated methanol permeability. We propose the preparation of a novel type of hybrid membranes to tentatively solve this problem. This innovative material results from the homogeneous dispersion of a nano-scaled inorganic filler within Nafion. The filler consists of stacks of negatively charged alumino-silicate layers (Cloisite), with a positive counter-ion in the interlamellar space. The purpose of the addition of this filler is to decrease methanol diffusion through the polymer membrane without decreasing too much the ionic conductivity.

Experimental evaluation of emission factors of cement kilns burning hazardous wastes

Cement industry is an interesting way to eliminate combustible wastes. Thermal valorization is maximal, conditions of combustion are especially favorable to the destruction and the trapping of pollutants, and there are neither ultimate residues (slag) nor aqueous rejects. Moreover the properties of the cement are not modified. Nevertheless the increased use of substitution fuel may lead to deal with unusual amounts of heavy metals. Tests were realized on several rotary cement kilns with varying substitution ratios of fossil fuels by wastes. Mass balances were fitted over the whole plant, and emission factors were explained.

Obtaining Intrinsic Kinetic Data Using a Micro Trickle Bed Reactor: The Hydrogenation of Glucose on Supported Ruthenium

Intrinsic kinetic data in gas-liquid-solid systems can be obtained in a micro-trickle bed reactor by controlling carefully the flow rates, the catalyst granulometry and the liquid distribution. This technique has been used to study the hydrogenation of glucose to sorbitol on ruthenium catalysts.

Life cycle engineering: methods, databases and results

The aim of this paper is to give an overview of the Life Cycle Assessment (LCA) technique and of existing methods and databases. LCA is a technique to assess the potential environmental impact associated with a product or a service throughout its life cycle from raw material acquisition through production, use and disposal. The International ISO Standards provide principles, framework and methodological requirements for conducting LCA studies.

Industrial Applications of Three Phase Catalytic Fixed Bed Reactors

Reactions between a gas and a liquid catalyzed by a solid are frequently encountered in chemical processes of great economical significance. Very often, it is technically impossible to operate with just one fluid phase, gas or liquid, in the reactor. The occurence of two fluid phases mainly depends on the temperature range in which the reaction can occur. It is well known that the low temperature limit depends on kinetics and catalysis whereas the highest possible temperature is fixed either by thermodynamics either by the product and the catalyst heat sensitivity. Nevertheless, some reactants, even at rather low temperature, will never been condensed or soluble enough to eliminate the gas phase. On the other hand, other reactants will never been completely vaporized whatever the temperature. Therefore, three phase catalytic processes will always occur when the volatility of two reactants is very different. This broad class of reactions is very important in chemical industry and, as we shall see, will be more frequent in the future.