Mise au point d’un procédé expérimental de quantification de la teneur totale en créosote dans les bois imprégnés

Organic preservatives like creosote are used to preserve wood from insects, fungi and water damage for many years. Poles for electric power or telephone and railroad sleepers are treated with this preservative and generate wood waste for which environmentally friendly treatment technologies need to be developed in the near future. These wood wastes which represent a large volume of material are classified as dangerous waste. These waste streams sum up to 100 000 ton of material per year in every major country of the European Community. While various types of creosotes have been extensively analysed as reported in various publications, a rapid method of evaluation of the quantity of creosote present in a given sample is not available. The present work is an attempt to validate such a protocol using Infrared spectroscopy, allowing the evaluation of the mass content of creosote in impregnated woods. La créosote est largement utilisée comme fongicide dans le traitement des bois d’extérieur (traverses de chemin de fer, poteaux électriques et téléphoniques) pour pallier aux effets climatiques (vent, pluie) et aux dégradations néfastes engendrées sur les insectes. Ces bois en fin de vie représentent actuellement un gisement de 100 000 tonnes de déchets par an sur l’ensemble de la Communauté européenne. Le retraitement et la valorisation de ces déchets dangereux monopolisent un grand nombre d’études. Si l’identification et la quantification de la totalité des molécules organiques aromatiques contenues dans une créosote sont largement décrites dans la littérature par l’utilisation de la chromatographie en phase gazeuse, la teneur globale en créosote d’un bois imprégné n’est en général pas connue. Cette étude expérimentale présente un protocole rapide de quantification de la teneur totale en créosote dans un bois imprégné par spectroscopie infrarouge

Collection of substantial amount of fine and ultrafine particles during the combustion of miscanthus and forest residues in small and medium scale boilers for morphological and chemical characterizations

Renewable energies are destined to play a very important role in the future world energy balance. Among these energies, biomass production and utilization is growing considerably since it offers the possibility to provide partial substitution of fossil fuels. If health impacts of fine particles (PM2.5) from diesel combustion are well documented (Gangwar et al., 2012), those from biomass combustion need substantial information and improvements. Size fractionations of PM2.5 have to be performed in order to both determine morphological and chemical characteristics, these properties being essential for biological effects. Particulate matter was sampled during combustion of miscanthus and forest residues in medium and small scale biomass boilers (400 kW from Köb Pyrot and 40 kW from REKA). Fly ashes from medium scale boiler were sampled with a cyclone device and their granulometry was studied with both optical microscope and Malvern laser granulometer. PM2.5 (sized in the range of 0.4 μm to 2.07 μm) from low scale boiler were sampled using a DEKATI DGI impactor modified for substantial PM collection. A quick overview of setup modifications for manual impactor will be developed. Particles were observed using fluorescence microscopy. A semi-quantitative method to compare fly ashes fluorescence was developped using ImageJ (Schneider et al., 2012). Speciation of organic compounds Polycyclic Aromatic Hydrocarbon (PAH) and Humic Like Substances (HULIS) was determined on PM2.5 and fly ashes. A correlation between observed fluorescence and concentration was attempted

Analysis of the combustion of pellets made with three Cameroonian biomass in a domestic pellet stove

In Sub-Saharan houses, the growing demand of fuels calls for the identification of new renewable and local resources such as biomass, suitable for energy production in small-scale stoves. In these countries, the three-stone-fire type is the most common stove and its use usually leads to high gaseous and particulate emissions. In the present study, combustion experiments of pellets made with three Cameroonian biomass in three different proportions were performed in a domestic pellet stove. The gaseous and particulate emissions were measured in derivations of the exhaust tube through appropriate gas analyzers or collecting filter. The CO concentration was measured between 476 and 675 mg/Nm(3), depending on the pellets. The Total Suspended Particles (TSP) were measured in the range 130-240 mg/Nm(3), depending on the pellets. These gaseous and TSP emissions were much higher than that obtained when burning normalized EN+ pellets in the same pellet stove. The combustion efficiency was evaluated between 68.5 and 80.2%, depending on the pellets, through standard computations. These values were found in the same range as that (78.2%) obtained when burning normalized EN+ pellets in the same domestic pellet stove