Papers by Jacques Mercadier
Journal of Supercritical Fluids, Dec 1, 2004
The scale-up of hydrothermal oxidation process depends on the development of simulation tools. Th... more The scale-up of hydrothermal oxidation process depends on the development of simulation tools. The reaction in a supercritical water oxidation reactor which is confronted to a non-stationary conditions is unknown, because these manipulations could create irreversible damages to the reactor materials. In this way, we have proposed a new numerical program to determine the reactor comportment in these situations. This program permits to model mass flow rate variations (start or stop of the reactor, for example), a modification of the inlet temperature and the change of waste concentration. This program will be able to determine the functioning conditions (temperature, and waste concentration which can be destroyed) with any risk for an industrial installation.
Industrial & Engineering Chemistry Research, Sep 4, 2003
The scaling up of a hydrothermal oxidation (HTO) facility depends on the development of simulatio... more The scaling up of a hydrothermal oxidation (HTO) facility depends on the development of simulation tools. In this way, a new approach to simulate the reactor thermal behavior during a nonstationary regime such as the start, stop, or emergency stop of the unit is developed. A numerical procedure of nonstationary temperature profile simulation in the reactor is described in order to predict the reactor thermal behavior. This new model is validated from experimental data obtained with a quasi-adiabatic reactor, which allows one to follow the temperature profile evolution along the reactor during the HTO process. Performances of the numerical procedure are tested with the simulation of three kinds of real nonstationary conditions: facility start, pump defect, and waste concentration dilution. The simulation gives the evolution of temperature profiles of a reactive mixture versus time and models the external wall temperature of the reactor tube versus time. These three simulations show that the HTO reactor thermal operation can be considered as stable and sure. Furthermore, they put in a prominent position that the risks of reactor damage are limited.
La pyrolyse des isocyanurates produit les isocyanates correspondants. Ainsi, celle du tribenzylis... more La pyrolyse des isocyanurates produit les isocyanates correspondants. Ainsi, celle du tribenzylisocyanurate donne du benzylisocyanate. Le benzonitrile, le benzene, le toluene et le monoxyde de carbone sont egalement formes. En milieu anhydre, la pyrolyse du triphenylisocyanurate produit le phenylisocyanate avec des rendements atteignant 100 pour-cent. L'acide isocyanurique se pyrolyse en donnant l'acide isocyanique avec des rendements atteignant 85 pour-cent. Cependant, ce dernier se decompose lui-meme thermiquement. Les cinetiques globales des reactions du triphenylisocyanurate et de l'acide isocyanurique ont ete determinees dans un reacteur tubulaire assimilable a un reacteur piston. La pyrolyse de l'acide isocyanurique a alors ete realisee dans un reacteur cyclone qui permet, en moins d'une seconde, de chauffer, sublimer, separer les particules non sublimees et, enfin, de le pyrolyser en phase gazeuse. Sa sublimation, assez facile, a ete modelisee de facon satisfaisante et il semble alors possible de prevoir ses resultats dans un cyclone de dimensions quelconques. Un modele charge de decrire la pyrolyse de l'acide isocyanurique en reacteur cyclone a egalement ete elabore. Il tient compte de sa liberation progressive en phase gazeuse dans le reacteur.
HAL (Le Centre pour la Communication Scientifique Directe), 2009
HAL (Le Centre pour la Communication Scientifique Directe), May 18, 2009
HAL (Le Centre pour la Communication Scientifique Directe), May 4, 2008
HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
Journal of Analytical and Applied Pyrolysis, May 1, 2003
The present paper shows that it is possible to carry out the thermal decomposition of solid parti... more The present paper shows that it is possible to carry out the thermal decomposition of solid particles followed, by the partial cracking of the evolved vapours, inside a cyclone rector heated at its walls. The results obtained with isocyanuric acid and with biomass particles are reported. From a mathematical model, it is possible to derive the kinetic constants of the
Journal of Supercritical Fluids, May 1, 2005
The purpose of this study is to test Runge-Kutta algorithm to obtain reliable kinetic parameters ... more The purpose of this study is to test Runge-Kutta algorithm to obtain reliable kinetic parameters for the hydrothermal oxidation of organic compounds. A tubular reactor system was used to carry out the oxidation of several model compounds: acetic acid, methanol and phenol. All experiments were performed in isothermal conditions in a temperature range varying from 250ºC to 500ºC and at a constant pressure of 25 Mpa. Three different methods, namely pseudo first order kinetics, multiple linear regression and Runge-Kutta algorithm, were used to determine the kinetic parameters. Results obtained by these different methods were similar, so that Runge-Kutta algorithm was validate for the determination of kinetic parameters. In contrast with the pseudo first order kinetics and the multi linear regression, Runge-Kutta algorithm was more convenient for the kinetic parameter determination starting from experiments performed at the laboratory scale or in industrial scale pilot plant facilities.
Journal of Supercritical Fluids, Mar 1, 2008
Deposition of elemental sulphur in natural gas transmission line systems has been reported on onl... more Deposition of elemental sulphur in natural gas transmission line systems has been reported on only in recent times. The most common location is immediately downstream of a point of significant pressure reduction. A necessary step to eliminate solid sulphur deposition is to understand the deposit mechanism. Two mechanisms appear possible: condensate formation and desublimation of sulphur vapours. To study the plausible paths of solid sulphur formation, we established a thermodynamic model. The constitutive equations are classically the chemical and physical equilibriums, partial mass balances and energy balance. We chose the Peng Robinson equation of state to describe the phase behaviour. Mixing rules are conventional: quadratic for a and linear for b with one binary interaction coefficient. Desublimation seems to be the most plausible mechanism to explain the solid sulphur formation. Pressure reduction implies temperature reduction, which reinforces solid formation. A solution to minimize the solid sulphur deposition seems to be heating the gas stream immediately before pressure reduction.
HAL (Le Centre pour la Communication Scientifique Directe), Aug 28, 2010
Journal of Analytical and Applied Pyrolysis, Feb 1, 1994
ABSTRACT
HAL (Le Centre pour la Communication Scientifique Directe), 2017
HAL (Le Centre pour la Communication Scientifique Directe), 2015
HAL (Le Centre pour la Communication Scientifique Directe), 2014
Journal of Supercritical Fluids, Sep 1, 2007
The aim of this study is to understand the thermal behaviour at the inlet of a hydrothermal oxida... more The aim of this study is to understand the thermal behaviour at the inlet of a hydrothermal oxidation reactor. This reactor was designed to eliminate charged waste water and operating in turbulent flow to limit corrosion at the injection points. Three numerical modelling were carried out to simulate the thermal behaviour of the reactor. The first program simulates the reactor operating in turbulent flow. The second one takes into account the problem of injection and the last one simulates a laminar flow with injection. Only, the program in laminar flow gives a good estimation of the thermal behaviour in the first meters of the reactor, in spite of the calculated Reynolds number which is higher than the critical one. However, in these operating conditions the flow has to be in a intermediate state. It seems that viscosity is larger than the one of pure water and the flow is laminar.
Journal of Chemical & Engineering Data, Jul 31, 2009
Journal of Supercritical Fluids, Jun 1, 2010
HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
Journal of Supercritical Fluids, Oct 1, 2005
This work studies the thermal behaviour of a tubular reactor when a reactive fluid is near and at... more This work studies the thermal behaviour of a tubular reactor when a reactive fluid is near and at the critical point. A numerical model was developed to simulate the critical behaviour of the fluid in a tubular oxidation reactor during stationary and non-stationary operation. These simulations are validated in steady state by a theoretical analysis and permit to know the thermal behaviour of the reactor. Physical phenomena, which can appear at the critical point, are known for pure water, but their effects in an oxidation reactor containing waste compounds are not studied. Simulated temperatures, velocities and concentrations profiles allow to evaluate the critical reactor behaviour and to identify the conditions of reactor stability. The major conclusion of this study is that the reactor is thermally stable and, in fact, more stable than at classical supercritical conditions.
Chemical Engineering Journal, Sep 1, 2007
The purpose of this work is to propose a model able to estimate the solubility of sulphur in natu... more The purpose of this work is to propose a model able to estimate the solubility of sulphur in natural gas transmission and distribution networks. Thus, we developed a model to predict the equilibrium solubility of elemental sulphur in natural gas containing low amount of H2S, at pressure and temperature ranges lower than those encountered in production conditions. We established a
Journal of Supercritical Fluids, Nov 1, 2001
HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
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Papers by Jacques Mercadier