Добірка наукової літератури з теми "Couplage plasma-catalyse"
Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями
Ознайомтеся зі списками актуальних статей, книг, дисертацій, тез та інших наукових джерел на тему "Couplage plasma-catalyse".
Біля кожної праці в переліку літератури доступна кнопка «Додати до бібліографії». Скористайтеся нею – і ми автоматично оформимо бібліографічне посилання на обрану працю в потрібному вам стилі цитування: APA, MLA, «Гарвард», «Чикаго», «Ванкувер» тощо.
Також ви можете завантажити повний текст наукової публікації у форматі «.pdf» та прочитати онлайн анотацію до роботи, якщо відповідні параметри наявні в метаданих.
Дисертації з теми "Couplage plasma-catalyse":
Bouchoul, Nassim. "Valorisation du dioxyde de carbone par couplage plasma non-thermique et catalyse." Thesis, Poitiers, 2019. http://theses.univ-poitiers.fr/62720/2019-Bouchoul-Nassim-These.
The two main greenhouse gases emitted by human activities are carbon dioxide and methane. Within the context of the current environmental crisis, it has become vital to find a method to valorise these gases. Therefore, this thesis has been conducted to be a part of this process: CO2 and CH4 valorisation. To this end, dry reforming of methane was carried out by coupling non-thermal plasma and catalysts. Metal-based catalysts, such as Ni/Al2O3, are usually used for plasma-catalyst. However, the results are often dissimilar, and even contradictory, as far as conversions and selectivities are concerned. In order to better understand the reasons behind this heterogeneity, the influence of the nature of the solid was studied. For this purpose, metal oxides, such as γ-Al2O3, α-Al2O3, MgO, CaO, La2O3, ZnO, CeO2, SiO2, BaO, TiO2, and a zeolite, were selected because of their respective physicochemical properties (permittivity, acidity, basicity, specific surface). These oxides were submitted to identical tests with identical operational conditions, e.g. a dielectric barrier discharge reactor (DBD), 8W power (800 Hz frequency, 13 and 16 kV tension), a total output of 40 mL.min-1 and a CH4/CO2=0,5 ratio.The study of the physical characteristics of catalysts highlighted the impact of the material’s permittivity or of the size of its grains on the discharge. A high dielectric constant hindered the reaction. When TiO2 (εr=2903) was found in the discharge, it led to a decline in CH4 and CO2 conversions, as they decreased from respectively 20 and 9% without catalyst, to 5 and 2% with TiO2. Furthermore, when grains were too large, there was less surface accessible to plasma, which led to a fall in the reagents’ conversions. Indeed, they dropped from respectively 30 and 15% for CH4 and CO2 for small-sized grains (250-355µm), to 24 and 11% for the largest grains (800-1000µm). In addition to this, the study of the catalysts’ chemical properties showed how basicity influenced the conversions of carbon dioxide. It seemed that when there was a great number of basic sites in a solid, CO2 adsorption was likely to be better. Furthermore, a more detailed study was carried out by coupling calcium oxide with non-thermal plasma. Indeed, the former does not only have a low permittivity, but also a high number of basic sites. Structural and textural modifications appeared after plasma. This was shown by examining the influence of the CH4/CO2 ratio and of the temperature on CaO. When there was a CH4/CO2 = 2 ratio, for a temperature of 300°C, the production of water (reverse water-gas shift reaction) tended to result in the formation of Ca(OH)2 and CaCO3.When water (0,1g.h-1) was added to the reaction mixture, CaO hydroxylation and Ca(OH)2 carbonatation were observed. Furthermore, hydrated calcium hydroxide (Ca(OH)2+ 18% H2O) carbonatation is more likely to occur under plasma. The analysis of gases at the outlet by a mass spectrometer revealed an oscillatory phenomenon associated with CO2 adsorption. A reaction pathway, during which CO2 and H2O adsorption and elimination occur successively, was therefore put forward. A low-energy plasma (4W) is likely to cause carbonatation, as the solid is originally composed of 0,9Ca(OH)2, 0,9 H2O, 0,1 CaCO3, and is made of 0,1Ca(OH)2, 0,9CaCO3 after plasma. Thus, applying a non-thermal plasma seems to encourage CO2 diffusion at the core of Ca(OH)2+ 18% H2O. Carbonatation is a method to store CO2 but it is a slow process, which is often hindered by CO2 diffusion. In this study, plasma was proved to be a highly interesting process, provided that its efficiency could be increased
OUMGHAR, AHMED. "Valorisation du methane par un plasma d'air ou d'azote-couplage avec la catalyse heterogene." Paris 6, 1992. http://www.theses.fr/1992PA066281.
Gumuchian, Diane. "Développement et étude d'un procédé d'oxydation avancée de traitement de l'eau pour composés organiques résistants par couplage plasma/catalyse." Thesis, Paris 6, 2014. http://www.theses.fr/2014PA066577/document.
This work enabled the development of a method of water treatment by plasma/catalysis coupling.The plasma treatments were carried out in two different reactors: a point/plane reactor and a dynamic reactor.Both reactors allow to control the gas atmosphere of the treatment. The feasibility of the degradation of aceticacid has been proven. Some processing parameters in the point/plane reactor (treatment gas, gas flow rate andfrequency of discharge) and the dynamic reactor (liquid phase flow, concentration of the pollutant and injectedpower) were studied.A modeling of the process using Comsol Multiphysics and Scilab softwares was conducted. It was possible toobserve the importance of the way active species (mainly hydroxyl radicals) are brought to the solution.A Co3O4 powder catalyst was studied in order to couple the plasma treatment with a catalytic treatment. Thus,manipulations of catalytic ozonation were conducted. They highlighted the efficiency of the catalyst for thedecomposition of pollutants.Finally, the plasma/catalysis coupling produced promising results, since it improved the decomposition ofpollutants.Possible improvements of the process could be to maximize the amount of high voltage electrodes and toredesign their shape (electrodes in parallel, plane geometry, etc.). Depositing a thin layer of catalyst on thegrounded electrode by PECVD (Plasma Enhanced Chemical Vapor Deposition) technique has to be performed
Sonar, Shilpa. "Abatement of toluene through storage-regeneration sequential process : application of thermal and plasma assisted catalytic regeneration." Thesis, Université de Lille (2018-2021), 2021. https://pepite-depot.univ-lille.fr/ToutIDP/EDSMRE/2021/2021LILUR064.pdf.
Toluene is a toxic volatile organic compound (VOC) present in indoor and outdoor environments. The abatement of toluene is typically done by adsorption or catalytic oxidation. In the latter case, toluene is converted into CO2 and H2O, but toxic species can build up on catalysts, causing poisoning, deactivation, and sintering. To overcome these drawbacks, we propose innovative “storage-regeneration” hybrid processes based on sequential adsorption-thermal catalytic oxidation (ATC) and sequential adsorption-plasma catalysis (APC). These processes are divided into two steps: “storage step” where gaseous toluene adsorbed on the surface of material and “oxidation step” where the adsorbed toluene species is catalytically converted into CO2 and H2O in thermal or plasma environment. ATC process was tested on commercial Hopcalite (CuMnOx), Ceria-NR and UiO-66-SO3H. Hopcalite stands out from others owing to its high “useful” adsorption capacity and redox properties, allowing a high activity and CO2 selectivity in toluene oxidation. In APC process, the powder morphology and lack of synergy effect in Ceria-NR and UiO-66-SO3H does not allow to generate stable plasma. Thus only Hopcalite has been studied in depth in APC. It is observed that the oxidation activity of the adsorbed toluene is significantly affected by the process variables. The stability of material was investigated in both cases, and it was confirmed that Hopcalite materials are very stable as evidenced by various characterization techniques. The catalytic activity was enhanced by impregnating active phase such as silver which led to improvement in the CO2 selectivity and CO2 yield at very low silver loading in both ATC and APC. A thorough examination of the material revealed that a good balance of adsorption capacity and catalytic activity (Cu2+,3+ and Mn3+,4+) is required. Moreover, the energy cost of APC is in the range of acceptable level (11.6 kWh·m−3) as a result with further optimization in different experimental parameters, it can be easily scalable in cost-effective manner. Both ATC and APC allow to reach toluene abatement efficiency and conversion to CO2 above 95 % on first run and 75% on stabilized materials. These results show that both ATC and APC process could be a promising energy-efficient toluene abatement processes and open the path for further development and scale-up
Alloncle, Guillaume. "Analyse directe de catalyseur par couplage ablation LASER : spectrométrie d'émission atomique dans un plasma à couplage induit." Lyon 1, 2008. http://www.theses.fr/2008LYO10247.
Inorganic analyses are compulsory in heterogeneous catalysis. Classical techniques are time consuming, especially for alumina or silica matrixes, because of mineralization step. Direct analysis of solids by coupling laser ablation to ICP-AES appears as a promising alternative to XRF or ICP, with a total analysis time of few minutes. Laser ablation, affected by fractionation effects, requires knowledge of mechanisms occurring during ablation. Accurate quantitative analyses require a sufficient matrix matching between samples and standards. The purpose of this work is the evaluation of LA-ICP-AES coupling for the direct analysis of heterogeneous catalysts and the understanding of mechanisms involved. Results, obtained on different kind of catalysts, show that analytical performances in terms of linearity, repeatability and accuracy are significantly improved with the use of an internal standard and are comparable with XRF. Nevertheless, significant bias appears when samples and standards matrixes differ significantly. The study of mechanisms involved in the ablation of catalysts showed that the aerosol transported to the ICP is generated from the vaporization if the sample and its condensation into highly crystalline nano-particles and microparticles. Chemical composition of the aerosol revealed the occurrence of fractionation of elements between the two particles types. Even if fractionation occurs, the use of LA-ICP-AES coupling into the field of heterogeneous catalysis is promising for the quick diagnostic by qualitative analysis, quantitative analysis with appropriate standards, and localized analysis for mapping