Study of Temperature Fields and Heavy Metal Content in the Ash and Flue Gas Produced by the Combustion of Briquettes Coming from Paper and Cardboard Waste

The present study focused on the combustion of four types of briquettes made from paper and cardboard waste produced in Ouagadougou (Burkina Faso). Rotary and tubular kilns were used to study the combustion. The combustion mean temperatures, nitrogen, phosphorus and potassium (NPK) content in the ash and heavy metals content in the ash and the flue gas were analyzed. The combustion steady phase mean temperatures ranged from 950 °C to 750 °C were obtained according to briquettes type. The temperature favored the transfer of the heavy metal in the flue gas comparatively to the ash mainly for Hg, Cd and Pb. The Pb, Hg and Mn content in flue gas and the ash are higher than their content in the parent wood used for paper production due to the additive during the manufacturing process. The results showed a high content of heavy metal in flue gas produced by combustion of briquette made with office paper and in the ash for the briquette made of corrugated cardboard. Furthermore, the low heavy metal contain in the ash allow their use for soil amendment. However, ash contained a low proportion of NPK (less than 2%) which does not allow their usage as fertilizer alone

Combustion of vegetable oils under optimized conditions of atomization and granulometry in a modified fuel oil burner

The use of vegetable oils in burners represents an attractive alternative to the use of heating fuel oil (HFO) in heat production for domestic heating, small industrial units, drying of various products etc. In this work, a characterization of the combustion of cottonseed oil in a modified burner (type Riello 40N10) was performed to assess its ability to achieve proper combustion of vegetable oils in optimized conditions of atomization and granulometry. The quality of the combustion has been evaluated by the analysis of combustion products (CO, O-2, CO2, NO, NO2, SO2) and organic compounds including PAHs. Results show that the modifications made on the burner type 40N10 can achieve suitable spray conditions and give particle size within the recommended values for burners. In the case of Riello 40N10 burner, a fuel pressure of 28 bars is adequate and the minimum temperature required for oil preheating is 125 degrees C. When these conditions are achieved, cottonseed oil combustion leads to the emission of non-condensable gases and the organic compounds species as well as their concentration close to those of HFO. (C) 2013 Elsevier Ltd. All rights reserved

Experimental study of the co-gasification of wood and polyethylene in a two-stage gasifier

Co‐gasification of wood mixed with 20% (mass fraction) of polyethylene (PE) in a two‐stage NOTAR® fixed‐bed gasifier was studied in the present paper. The ratio of air flow injected in the pyrolyzer and air flow injected in the oxidation zone is called the air ratio (AR). The AR of 0.35, 0.43, and 0.49 were used for test runs. Mass and energy balances were established. The study showed the feasibility of co‐gasification of wood mixed with 20% of PE in the two‐stage gasifier. However, considerable quantity of residues rich in fixed carbon content (17% of the fuel mass and 69% of fixed carbon content) was produced due to a low reactivity of the charcoal obtained after the pyrolysis. AR increasing reduces the gas CO content due to overconsumption of char at the pyrolysis stage. H2 and CH4 highest values are obtained for the intermediate AR = 0.43 which maximized the LHV, energy efficiency, and carbon conversion with respectively 4674 kJ/Nm3, 64.35%, and 74.52%. Low reactivity and carbon content of the pyrolysis char likely lead to lower performance of co‐gasification of PE mixed with wood compared to wood gasification

Highlighting of a local non-equilibrium thermodynamics during the transfer of trichlorethylene (TCE) in the superficial layers of arid soils

International audienceIn this paper, we analyze and model the mass transfer of trichloroethylene in the surface layer of a soil. Our study essentially focuses on arid soils taking into account the phase change liquid-vapor. We have then examined the validity of the assumption of local equilibrium by comparing the values of the instantaneous pressure of the trichloroethylene vapor and the equilibrium vapor pressure during the transfer process. It appears that the assumption of local equilibrium during the transfer of trichloroethylene cannot be admitted

Etude de la Pyrolyse en Analyse Thermogravimetrique du Carton : Cinetique Double Etape en Regime Isotherme

International audienceLa pyrolyse semble être un procédé adapté au traitement des déchets à base de carton. Afin d’optimiser les conditions expérimentales du procédé de pyrolyse et d’apporter des éléments pour le dimensionnement d’une installation, une étude du comportement thermique du carton est indispensable. Dans le présent document, l’étude de la dégradation thermique d’échantillons de carton en conditions de pyrolyse a été réalisée par analyse thermogravimétrique. Des essais en régime isotherme sous atmosphère inerte (sous argon) à différentes températures 250, 280, 300 et 320°C ont été réalisés. Ces isothermes ont été choisies après détermination de la plage de température de dégradation du carton en utilisant l’ATG en régime dynamique. Un modèle cinétique en deux phases de pyrolyse a été utilisé pour déterminer les paramètres cinétiques : l’énergie d’activation, le facteur pré-exponentiel de la pyrolyse du carton ondulé dans les conditions isothermes