Richard T.,French National Center for Scientific Research |
Poirier J.,French National Center for Scientific Research |
Reverte C.,CNRS Institute of Chemistry |
Aymonier C.,CNRS Institute of Chemistry |
And 4 more authors.
Journal of the European Ceramic Society | Year: 2012
Supercritical water gasification (SCWG) is a very efficient process to convert wet biomass into energetic gases. Unfortunately, SCWG reactor may strongly corrode due to the addition of temperature, pressure and the presence of corrosive species. In the present paper, the corrosion of various ceramic materials in subcritical and supercritical water (SCW) gasification process was studied in a batch reactor. We compare the corrosion in distillated water and the corrosion in sugar beet slurry that will be gasified under supercritical conditions. The experimental temperatures were 350°C and 550°C and the pressure was 25MPa. Technical ceramics (SiC, alumina, Y stabilized zirconia, Si 3N 4, BN, aluminosilicate, cordierite-mullite) show poor capability to sustain corrosion whereas graphite and glassy carbon are the highest performance materials in our working conditions. © 2012 Elsevier Ltd.
Marias F.,Laboratoire Of Thermique Energetique Et Procedes |
Santacreu S.D.,French National Center for Scientific Research
Canadian Journal of Chemical Engineering | Year: 2015
This paper deals with the two dimensional modelling of transient pyrolysis of biomass in a fixed bed. The model that is developed mainly relies on the theory of volume averaging. This model includes heat and mass transfer and pyrolysis reaction. It allows the prediction of temperature, moisture content organic material content, and char content, as well as the prediction of internal evolution of the composition of the gas held and released from the sample under investigation. This model is used in order to describe pine wood pyrolysis taking place in a macro thermobalance which is also presented in the paper. Comparison of the numerical results with the experimental ones, in terms of mass loss of the sample, shows good agreement and validates the model. A deeper analysis of the results allows a better understanding of the processes involved in the thermal degradation. © 2014 Canadian Society for Chemical Engineering.
Sochard S.,University of Pau and Pays de l'Adour |
Fernandes N.,University of Pau and Pays de l'Adour |
Reneaume J.,Laboratoire Of Thermique Energetique Et Procedes
AIChE Journal | Year: 2010
Gas-phase adsorption equilibria of diluted mixtures of methyl-ethyl-ketone and isopropylanol on activated carbon were investigated. Experimental isotherms were determined by a constant volume method. Single-component adsorption isotherms were fitted by the frequently used Toth model with good accuracy. Then adsorption isotherms were determined for different binary mixtures (with different initial ratio of the two components). Binary mixtures adsorption isotherms were calculated using the adsorbed solution theory. Ideal adsorbed solution theory (IAST) could not represent experimental data, but it was observed that increasing amount of MEK led to higher nonideality of the mixture. Then UNIversal QUAsi Chemical (UNIQUAC) and nonrandom two-liquids (NRTL) models were considered to describe activity coefficients of the adsorbed phase. The fitted parameters of UNIQUAC model depend on the ratio of the two components, whereas the NRTL model is able to fit all experiments with the same parameters, whatever the initial ratio may be. © 2010 American Institute of Chemical Engineers AIChE.
Deydier A.,Europlasma |
Deydier A.,Laboratoire Of Thermique Energetique Et Procedes |
Marias F.,Laboratoire Of Thermique Energetique Et Procedes |
Bernada P.,Laboratoire Of Thermique Energetique Et Procedes |
And 2 more authors.
Biomass and Bioenergy | Year: 2011
A mathematical model describing a gasification process composed of a dryer section and of a gasification section is presented in this work. This model is based on the equilibrium assumption within both sections. The whole set of assumptions used in the model are presented in the paper as well as the derivation of the corresponding equations. The temperature of both sections is computed using energy balances. The numerical predictions of the model are compared to available data describing the gasification of coal, wood and grass. The influence of two operating parameters of the system is investigated in the study. The first one is the ratio of air supplied to the dryer to the biomass fed to this section. Our computation clearly shows the existence of an optimal value for this parameter. In the same manner, the influence of the ratio of air supplied to the gasifying section to the incoming biomass is investigated. Once again, this parameter shows an optimal value. © 2010 Elsevier Ltd.
Jegadheeswaran S.,Tolani Maritime Institute |
Pohekar S.D.,Tolani Maritime Institute |
Kousksou T.,Laboratoire Of Thermique Energetique Et Procedes
Clean - Soil, Air, Water | Year: 2011
Phase change material (PCM) employed latent heat thermal storage (LHTS) system has been showing good potential over the years for energy management, particularly in solar energy systems. However, enhancement in thermal conductivity of PCMs is emphasized as PCMs are known for their poor thermal conductivity. In this work, the thermal performance of a shell and tube LHTS module containing PCM-metal particles composite is investigated while charging and is compared with that of pure PCM system. The effect of particle dispersion on latent heat capacity of pure PCM is also analyzed. Enthalpy based governing equations are solved numerically adopting FLUENT code. Exergy based performance evaluation is taken as a main aspect. The numerical results are presented for various operating conditions of heat transfer fluid (HTF) and indicate considerable performance improvement of the system when particles are dispersed. Phase change materials are known for poor thermal conductivity. Here, the thermal performance of a shell and tube LHTS module containing PCM-metal particles composite is investigated while charging. The numerical results are presented for various operating conditions of heat transfer fluid and indicate considerable performance improvement when particles are dispersed. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Olivier J.,Laboratoire Of Thermique Energetique Et Procedes |
Mahmoud A.,Laboratoire Of Thermique Energetique Et Procedes |
Vaxelaire J.,Laboratoire Of Thermique Energetique Et Procedes |
Conrardy J.-B.,Laboratoire Of Thermique Energetique Et Procedes |
And 2 more authors.
Drying Technology | Year: 2014
Electro-dewatering experiments were carried out on a laboratory-scale device to analyze the energy consumption under both a constant voltage (C.V.) and a constant current density (C.C.). The purpose of this study was to determine the impact of electro-dewatering parameters (voltage, current density, pressure, and amount of sludge to be treated) on energy consumption. The results of the C.V. experiments showed a very strong correlation between the applied voltage, the final dryness of the sludge filter-cake, and the total energy consumption (Wh/kgadditional water removed). The calculation of the instantaneous energy consumption allowed us to determine the range of dryness where the electro-dewatering process (EDW) was energetically more advantageous than thermal drying. The instantaneous energy consumption depends mainly on the reached dryness. It does not significantly depend on other process parameters such as the applied voltage, the applied current density (in), the applied pressure, or the initial amount of sludge. In fact, the change in electrical power consumption due to different test conditions was balanced by changes in kinetics. The comparison between two tests (one with C.V. conditions, the other with C.C. conditions) showed that the kinetics were similar when the electrical power consumption was the same. The results of this work lead to two main findings: the dewatering kinetics depends essentially on the current density; and the final dryness of the filter-cake depends mainly on the applied voltage. © 2014 Copyright Taylor & Francis Group, LLC.