Description of the materialGround oil shale semicoke was prepared in a laboratory retorting furnace under inert atmosphere. A laboratory combustion cell was then used to operate the combustion of the semicoke added with more or less sand and/or carbonates. This enabled to vary independently the amount of CaCO3 and the amount of fixed carbon in the mix. The temperature of the combustion front propagating in this mix was recorded, together with its velocity. The flue gas was analysed. ApplicationPropagating a combustion front through a fixed bed is a way to produce oil and a fuel gas from oil shale or to recover energy from oil shale semicoke in the retort process. When operated with air, this process involves high temperaturestypically larger than 1000C B0C -resulting in the decarbonation of the carbonate matrix and the emission of additional CO2. The aim of this work was to avoid this decarbonation. Results, Observations, and ConclusionsIt is shown that increasing the amount of CaCO3 in the medium (with constant fixed carbon amount) can decrease the combustion front temperature down to 800C B0C but not below, which is not sufficient to avoid decarbonation.Decreasing the amount of fixed carbon can decrease the temperature down to 600C B0C, a temperature at which decarbonation occurs only a bit. At this temperature, not all the oxygen in the fed air is used, which results in a slowing down of the combustion front. SPE 138143Significance of Subject Matter To our knowledge, no results have been published yet where the two parameters of carbonate amount and fixed carbon amount were varied independently, and where their impact on the front temperature and decarbonation were determined. Avoiding decarbonation in such processes is a potential very significant way to reduce CO2 emissions.

The solar heater is a system that generates hot water by converting solar energy to thermal energy. In these last few years, various ways have been developed to gather this natural energy. However, they can not be able to store the energy when the sun disappears. In this study, thermal system based on phase change materials that improves the hot water production and stores thermal energy is proposed. In order to describe phase change materials and considers the effects of inclination angle on the production and storing thermal energy a numerical study has been carried out using the ANSYS-Fluent software. In addition, details concerning the choice of calculation range, mesh size, boundary conditions and turbulence model have been provided. The numerical results have been compared with previous data that was very promising.

OATAO is an open access repository that collects the work of Toulouse researchers and makes it freely available over the web where possible. ABSTRACT: Results of an experimental investigation on the feasibility of propagating a smoldering front in reaction-trailing mode throughout an oil shale semicoke porous medium are reported. For oil recovery applications, this mode is particularly interesting to avoid low-temperature oxidation reactions, which appear simultaneously with organic matter devolatilization in the reaction-leading mode and are responsible for oxidation of part of the heavy oil. The particularity of this mode is that, contrary to the reaction-leading mode largely studied in the literature, the heat-transfer layer precedes the combustion layer. This leads to two separated high-temperature zones: (i) a devolatilization zone (free of oxygen), where the organic matter is thermally decomposed to incondensable gases, heavy oil, and fixed carbon, also called coke in the literature, without any oxidation, followed by (ii) an oxidation zone, where the fixed carbon left by devolatilization is oxidized. The transition from reaction-leading to reaction-trailing mode was obtained using low oxygen contents in the fed air. It is shown that two distinct layers, the heat-transfer layer and the combustion layer, propagate in a stable and repeatable way. The decrease of the oxygen fraction leads to a decrease of the smoldering temperature and to strongly limit the decarbonation of the mineral matrix. The CO 2 emissions are limited. Regardless of the front temperature, all of the fed oxygen is consumed and all of the fixed carbon is oxidized at the passage of the smoldering front.

This work focuses on the numerical and experimental study of convective heat transfer in a rotor of a discoidal the machine with an eccentric impinging jet. Convective heat transfers are determined experimentally in steady state on the surface of a single rotating disk. The experimental technique is based on the use of infrared thermography to access surface temperature measurement, and on the numerical resolution of the energy equation in steady-state, to evaluate local convective coefficients. The results from the numerical simulation are compared with heat transfer experiments for rotational Reynolds numbers between 2.38×105 and 5.44×105 and for the jet's Reynolds numbers ranging from 16.5×103 to 49.6 ×103. A good agreement between the two approaches was obtained in the case of a single rotating disk, which confirms us in the choice of our numerical model. On the other hand, a numerical study of the flow and convective heat transfer in the case of an unconfined rotor-stator system with an eccentric air jet impinging and for a dimensionless spacing G=0.02, was carried out. The results obtained revealed the presence of different heat transfer zones dominated either by rotation only, by the air flow only or by the dynamics of the rotation flow superimposed on that of the air flow. Critical radii on the rotor surface have been identified

The production and storage of thermal energy are important processes that contribute to the satisfaction of daily needs. They are effective ways of managing the thermal energy available from various solar applications. The most efficient storage technique is the use of phase change materials (PCMs) because these components can keep large amounts of thermal energy in stock. The problem is that this approach continues to be confronted with difficulties despite significant progress in research, design and modelling. Nevertheless, these difficulties can be resolved through numerical simulations that enable the identification of powerful tools for optimising thermal system design and predicting thermal behaviour. Correspondingly, in this work, thermo-mechanical modelling was conducted to describe the different methods of heat transfer that can optimise thermal energy storage via PCMs. This study also established a numeric resolution and the spatio-temporal discretisation of the basic equations accompanying the numerical model. The proposed numerical solution improves the prediction of thermal behaviour and can be used as a guide in designing new systems capable of producing and storing solar energy.