J. Koulidiati - Academia.edu (original) (raw)

Papers by J. Koulidiati

The characterization of the municipal solid wastes of the city of Ouagadougou, done from january ... more The characterization of the municipal solid wastes of the city of Ouagadougou, done from january to april 2001 reveal that incineration shoulb be a good way of treatment, notably due to the respectable PC! of those wastesduring the dry season: A preliminary study has been conducted with a combustible mixture representative of the municipal solid waste of Poitiers. This one is composed of wood, cardboard and two kinds of plastic: PET and polyamide. The study has been performed into the « Laboratoire de Combustion et de Detonique » into poitiers using a counter flow fixed bed reactor. The work focussed on the influence of the excess air of combustion on the emissions of NO and CO and particularly on the repartition of the air between the primary and the secondary injection. The results obtained demonstrate that the NO emissions increase with the total excess air than the CO emissions first decrease before to increase. Thus the experimental conditions permitting a reduction of the CO a...

Global Journal of Pure and Applied Sciences, 2016

Quasi-steady state thermal performance of a solar air heater with a combined absorber is studied.... more Quasi-steady state thermal performance of a solar air heater with a combined absorber is studied. The whole energy balance equations related to the system were articulated as a linear system of temperature equations. Solutions to this linear system were assessed from program based on an iterative process. The mean temperature variation with time and the thermal performance parameters were deduced from simulation outputs. Simulations were performed for typical days of the twelve months of the year. Results show maximum values of mean temperatures at solar noon ranging between: 78°C and 87°C for the cover, 102°C and 114 °C for the absorber 61°C to 67°C. Experimental and simulated results correlate well for hours before solar noon (with R²≈0.988) and show some discrepancies for hours after solar noon. These differences were related to the neglect of heat capacity effects in the model. Experimental and calculated solar heater efficiencies at solar noon approached respectively about 62 and 61%. The removal factor FR and the efficiency factor F' calculated were respectively 0.4 and 0.33, whereas the values assessed from experiments were respectively 0.79 and 0.63. This model allowed predicting the collector performances and is more suitable for hours before solar noon.

Journal des Sciences Pour l'Ingénieur, 2011

ABSTRACT Dans cette étude, une caractérisation du séchage convectif de la variété de mangue « Amé... more ABSTRACT Dans cette étude, une caractérisation du séchage convectif de la variété de mangue « Amélie » est réalisée à travers l’établissement des cinétiques de séchage de 50°C à 70°C et de l’isotherme de désorption à 40°C. La diffusivité effective est identifiée et varie de 0,75x10-9m².s-1 à 50°C, à 1,07x10-9m².s-1 à 60°C et 1,29x10-9m².s-1 à 70°C. L’énergied’activation déterminée à partir de données expérimentales est de l’ordre de 25 kJ/mole. Parmi les modèles semi-empiriques de cinétique de séchage et d’isotherme de désorption, le modèle de Page, avec un coefficient de corrélation supérieur à 0,99, s'est avéré le meilleur modèle pour décrire les courbes de séchage de l’ «Amélie », tandis que les modèles d’Henderson modifié, de GAB et de Peleg ajustent convenablement l’isotherme à 40°C de cette variété de mangue. La teneur en eau correspondant à l’activité de l’eau de conservation 0,6 est évaluée à 15,31% (base sèche) et la teneur en eau en monocouche d’eau identifiée à partir du modèle de GAB est de 10,5 % (base sèche). In this study, a characterization of the convective drying of « Amélie » mango variety is carried out through the establishment of drying kinetics from 50°C to 70°C and of the desorption isotherm at 40°C. The effective diffusivity is identified and varies from 0.75x10-9m².s-1 at 50°C, to 1.07x10-9m².s-1 at 60°C and 1.29x10-9m².s-1at 70°C. The activationenergy determined from experimental data is about 25kJ/mole. Among semi-empirical models of drying kinetics and desorption isotherm, the Page model, with a correlation coefficient higher than 0.99, was found to be the best model to describe " Amélie " drying curves, while Modified Henderson, GAB and Peleg models suitably fitted the desorption isothermat 40°C of this mango variety. The moisture content corresponding to 0.6 water activity of conservation is evaluated at 15.31% (dry basis) and the mono-layer water content identified from the GAB model is X m=10,5% (dry basis).

Journal of Analytical and Applied Pyrolysis, 2013

To simulate the emission of hydrogen chloride gas and free chlorine from the thermal treatment of... more To simulate the emission of hydrogen chloride gas and free chlorine from the thermal treatment of plastic materials, especially those based on PVC, two mathematical models have been developed. An experimental research program has been undertaken to validate these models. It is found that the masses of hydrogen chloride and free chlorine computed with these models are in good agreement with the experimental results. According to these results, it can be assumed that the quantity of hydrogen chloride and free chlorine produced during the thermal treatment of PVC-based materials strongly depends on the pyrolysis temperature and duration. The agreement between the results from simulations and empirical studies also shows the capability of these models to predict the amount of gas that will be produced from PVC-based materials upon thermal treatment.

Journal of Analytical and Applied Pyrolysis, 2009

ABSTRACT This study aims to experimentally characterize the carbonaceous and nitrogenous species,... more ABSTRACT This study aims to experimentally characterize the carbonaceous and nitrogenous species, from the flash pyrolysis of millet stalks and polyethylene plastic bags, using the device of the tubular kiln, coupled to two gas analyzers: Analyzer Fourier Transform Infrared (FTIR) and an analyzer Infrared Non-Dispersive (IRND). Gaseous products analyzed are: CH4, C2H2, C2H4, C3H8, C6H6, CO, CO2, NO2, NO, N2O, HCN and NH3. Whatever the temperature of thermal degradation, the pyrolysis shows us that in terms of mass:•For the millet stalks, the gaseous compounds are formed mainly CO and CO2 to the carbonaceous species, HCN and NH3, for the nitrogenous species analyzed;•As regards the polyethylene bags, hydrocarbons for carbonaceous species and HCN, NH3 and NO2 for the nitrogenous species, are most abundant.In addition, the results suppose that in our experimental conditions, the hydrocarbon which is involved primarily in the formation of CO is ethylene C2H4. At the end of this characterization, we determined the rate of carbon and nitrogen found in the volatile gas. With millet stalks we have about 45% of volatile carbon and 15% of the nitrogen of fuel that are found in gaseous products. The results obtained with the plastic bags give 68% carbon and 15% nitrogen found in the nitrogenous species analyzed.

International Journal of Thermal Sciences, 2006

A numerical model has been developed to study the NO x formation during the combustion of mixture... more A numerical model has been developed to study the NO x formation during the combustion of mixtures of cellulosic and plastic fuels within a fixed bed reactor. The model simplifies the flow to a one dimensional succession of about 1000 perfectly stirred reactors (PSR) and includes a detailed chemical model that computes 113 species involved in 893 reversible reactions, to detailed the reactive path of NO x formation. The calculations use the PSR model included in Chemkin II. The solid phase is not solved but instead the input species are generated from an experimental degradation study of the fuel. Nitrogen oxide (NO) is studied as the primary component of NO x. The model has been validated in past publication by comparison of the results with experimental measurements. The model has then been used to investigate the mechanisms of formation and destruction of the NO during the combustion process of municipal solid waste. Numerical results show that NO forms rapidly from the oxidation of intermediary species such as NCO, HNO and NH that originate from the fuel pyrolysis. NO consumption occurs primarily through reactions with NH i and NCO leading to the formation of N 2. The ultimate formation and consumption of NO depends mostly on the primary air flowing through the fuel bed with a minimum being observed when primary air and fuel are present in proportions close to stoechiometric.

Drying Technology, 2014

ABSTRACT From experimental data, Spirulina effective moisture diffusivity was analytically estima... more ABSTRACT From experimental data, Spirulina effective moisture diffusivity was analytically estimated by considering two diffusion regions and the product shrinkage. Then, the moisture diffusivity was deduced from the numerical solutions of mass transfer equations by minimizing the difference between experimental and simulated drying curves and by taking into account the slab thickness variation. The range of moisture diffusivity used for simulations was estimated from minimal and maximal values of experimental effective diffusivities and calculation started with the mean value of experimental effective diffusivities. Identified effective diffusivities ranged from 1.79 × 10−10 to 6.73 × 10−10 m2/s. These diffusivities increased strongly with drying temperature and decreased slightly with moisture content. A suitable model correlating effective diffusivity, temperature, and moisture content was then established. Effective diffusivities given by this model were very close to experimental ones with a relative difference ranging from 0.5 to 24%.

High Temperature Material Processes (An International Quarterly of High-Technology Plasma Processes), 1998

HAL is a multi-disciplinary open access archive for the deposit and dissemination of sci-entific ... more HAL is a multi-disciplinary open access archive for the deposit and dissemination of sci-entific research documents, whether they are pub-lished 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 a ̀ 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.

Informacion del articulo Epuration des eaux usees urbaines par lagunages a microphytes et a macro... more Informacion del articulo Epuration des eaux usees urbaines par lagunages a microphytes et a macrophytes en region tropicale: la station experimentale de Niamey - NIGER

Energy and Power Engineering

The past literature on the use of vegetable oils as fuel in diesel engine revealed that utilizing... more The past literature on the use of vegetable oils as fuel in diesel engine revealed that utilizing vegetable oil fuels in diesel engines may require property changes in the oil or perhaps, some minor engine modifications or operating changes. This study was conducted to search for the effect of atmospheric oxygen on the puffing and bursting phenomena that occur during vegetable oils droplet vaporization process in their use as fuel in diesel engine. The fiber-suspended droplet technique was used, and the normalized square droplet diameter as well as the temperature evolution vicinity the droplet was analyzed. The results show that puffing and bursting phenomena highly depend on oxygen. In presence of atmospheric oxygen, there is an increase of the puffing and bursting intensity and therefore the evaporation rate of the vegetable oil droplets, but in an inert environment or when the environment is oxygen-depleted puffing and bursting phenomena disappearing and make place of a series of explosions with lower magnitude. The lack of oxygen reduces the thermal degradation, polymerization and oxidation reactions and consequently the vaporization rate of vegetable oils droplets; and could therefore lead to the formation of deposits in the form of polymers. This is unsuitable for their use as a fuel in diesel engines. It can also be concluded that atmospheric oxygen has some positive effects on engine performance and emissions when operating with vegetable oil. These results help to address the challenge for the use of alternative fuels such as non-edible vegetable oils.

Acta Physica Polonica A, 1998

Solar Energy, 2016

Abstract In this work, a solar air collector with a composite absorber is designed and experiment... more Abstract In this work, a solar air collector with a composite absorber is designed and experimented. Its composite absorber results from the coupling of a non-porous absorber made of a corrugated iron sheet and a porous absorber made of a mesh of aluminum. The prototype collector was modeled in unsteady-state by considering heat capacity effects in its components. The temperatures were simulated by solving energy balance equations relating to each component. Solutions to these equations gave temperatures variation according to time of the day and distance from collector inlet. Results show that the collector overall thermal efficiency approximates 61% at solar midday with maximum temperatures of 77, 142, 107 and 73 °C respectively for glass cover, non-porous and porous absorbers and airstream. Compared to quasi-steady state studies, unsteady state studies lead to results in better agreement with experiment. Experimental and unsteady state simulated temperatures were very close and unsteady state model therefore allowed predicting suitably collector performances.

Le Journal de Physique Colloques, 1990

Clean Air: International Journal on Energy for a Clean Environment, 2006

An experimental study has been conducted with a fixed-bed reactor to simulate, on a laboratory sc... more An experimental study has been conducted with a fixed-bed reactor to simulate, on a laboratory scale, industrial municipal waste incineration. The observation of the combustion regimes established has served to show the impact of the operating conditions on the yields of nitrogen oxide. Two different regimes have been identified, controlled by the airflow rate through the fuel. The present experimental results show that the production of NO seems to be controlled only by the oxygen concentration in the secondary zone of combustion. An increase in total air-flow rate, thus, results in an increase in the yield of NO.

Le présent travail est une étude expérimentale comparative des émissions d'espèces gazeuses lors ... more Le présent travail est une étude expérimentale comparative des émissions d'espèces gazeuses lors de la combustion de granulés de polyéthylène pur et de sachets plastiques à base de polyéthylène. Deux paramètres importants de la dégradation thermique sont étudiés pour chacune des deux matrices : la température et la masse. Cette étude a été réalisée à l'aide du dispositif expérimental du four tubulaire. Les résultats obtenus montrent que la masse et la température sont des paramètres influençant significativement les émissions des espèces gazeuses lors de la combustion de matériaux plastiques à base de polyéthylène. En effet, nous remarquons que le monoxyde d'azote (NO) est une fonction croissante de la température et une fonction décroissante de la masse de combustible ; tandis que le dioxyde de carbone (CO 2) est une fonction croissante de la température et de la masse de combustible brûlée. En dernier lieu, la comparaison des émissions gazeuses pour chacune des deux matrices de PE donne des écarts compris entre 0 et 15%. Ces écarts nous montrent qu'il est possible de substituer les sachets plastiques en faveur des granulés de PE lors d'expériences en laboratoire.

Dans cette étude, un dispositif de réfrigération basée sur l'évaporation de l'eau à travers une p... more Dans cette étude, un dispositif de réfrigération basée sur l'évaporation de l'eau à travers une paroi poreuse en poterie est conçu, simulé et expérimenté. L'architecture originale de ce réfrigérateur local a été conçue à partir de l'idée d'optimiser les paramètres pouvant influencer son fonctionnement tout en minimisant le volume d'eau à évaporer à travers la paroi poreuse. Les résultats montrent que le fonctionnement du réfrigérateur est fortement influencé par les trois paramètres physiques dont dépend essentiellement l'évaporation de l'eau à travers un milieu poreux (la température et l'hygrométrie de l'air et la surface totale d'échange). L'analyse des courbes expérimentales et théoriques (simulation) montre que la température de l'eau du réfrigérateur ne peut être abaissée au-delà de la température de bulbe humide de l'air évaporateur. Un tel réfrigérateur en argile cuite aurait de possibles applications dans les cuisines et les Jardins pour la conservation des denrées, en campagne pour le rafraîchissement, sur les airs d'autoroute, dans les parcs nationaux et sur les campings des régions méditerranéennes.

High Temperature Material Processes (An International Quarterly of High-Technology Plasma Processes), 1997