Yes / Oxidative desulfurization process (ODS), enhanced with a novel metal oxide (Ag ions) as an active component over nano-zeolite that has not been reported in the literature, is used here to improve the fuel quality by removing mercaptan (as a model sulfur compound in the light naphtha). Nano-crystalline (nano-support (Nano-zeolite)) composite is prepared by Incipient Wetness Impregnation method loaded with a metal salt to obtain 0.5, 1 and 1.5% of Ag2O3 over Nano-zeolite. The new homemade nano-catalysts (Ag2O3/Nano-zeolite) prepared are characterized by Brunauer-Emmett-Teller (BET) (surface area, pore volume and pore size), X-ray Diffraction (XRD), Fourier Transform Infra Red (FTIR), and Scanning Electron Microscopy (SEM) analysis. The ODS process is then used to evaluate the performance of the catalysts for the removal of sulfur at different reaction temperatures (80-140 °C) and reaction times (30-50 min) in a batch reactor using the air as oxidant. 87.4% of sulfur removal has been achieved using 1% silver oxide loaded on Nano zeolite (1% of Ag2O3/Nano-zeolite) giving a clear indication that our newly designed catalyst is highly efficient catalyst in the removal of sulfur compound (mercaptan) from naphtha. A new mechanism of chemical reaction for sulfur removal by oxygen using the new homemade catalyst (Ag2O3/Nano-zeolite) prepared has been suggested in this study. The best kinetic model parameters of the relevant reactions are also estimated in this study using pseudo first order technique based on the experimental results.

Yes / Due to the environmental legislations related to sulfur content and proceeding with the challenges to find an appropriate catalyst of such contamination producing clean fuel, a main thrust for improving of more efficient technologies on new oxidative catalyst is viewed a vital issue in fuel quality development. So, in this study, the sulfur compound (ethyl mercaptan) presents in light naphtha feedstock is removed by oxidative desulfurization (ODS) in a batch reactor using a new homemade nano-catalyst and air as oxidant under different reaction conditions (reaction temperatures, reaction time and the initial sulfur concentrations) that has not been studied in such field. The catalyst is zinc oxide supported on zeolite nanoparticles which is locally prepared by Incipient Wetness Impregnation (IWI) method. Mathematical model of the relevant reactions is also developed in this study to match the experimental results via obtaining the optimal kinetic parameters utilizing optimization techniques within gPROMS program. Such optimization is conducted using two approaches (linear and nonlinear regression) and the results showed that the nonlinear approach is more accurate than linear approach. The optimal kinetic parameters are then used to achieve a clean fuel via getting the optimal operation conditions based on the maximum conversion. Where, higher than 99% of the process conversion has obtained at temperature of 327.4 K, reaction time at163.6 min and initial concentration of 335.3 ppm.

In the specified large combustion plant, fuel with a large content of sulfur is burned. The current desulfurisation method is not able to meet the new emission limits, therefore it is necessary to design an adequate desulphurisation method. The theoretical part of this diploma thesis contains a description of the legislation related to emission limits for large combustion plants and an analysis of individual technological methods of desulphurization together with a description of the relevant sorbents. The practical part of the work contains a design of dry conditioned sorption with the using of a calcium-based sorbent. The basic technological and structural design is designed together with the spatial solution and dispositional solution of the whole technology.

DE LA TESISEs una contribución al desarrollo de un nuevo método de purificación de gas de síntesis en plantas IGCC, que posibilita un incremento de la eficiencia energética de las plantas de obtención de energía, a partir de combustible fósil, y con ello reducir la emisión de gas de efecto invernadero a la atmósfera. Se estudia un proceso nuevo por absorción regenerativa en óxidos metálicos, capaz de eliminar los contaminantes del gas a alta temperatura, aprovechando con ello el contenido energético asociado al intervalo térmico, que los procesos actuales pierden en la purificación por vía húmeda. Se enumeran a continuación los objetivos concretos alcanzados, con las fases del trabajo desarrollado:1- Estudio de la cinética de la reacción de purificación del gas de síntesis, siguiendo las reacciones de absorción no catalíticas, con deposición de sólido, realizando un estudio exhaustivo, para conseguir unos modelos de reacción gas-sólido que contemplen el mayor número de posibilidades. Se ha pretendido crear una herramienta de simulación con el menor número de restricciones a la hora de aplicarlo a cualquier reacción que involucre cambio en la estructura del sólido con la conversión del mismo, para de este modo no tener un modelo cautivo de un determinado tipo de sorbente.2- Se han obtenido los parámetros cinéticos experimentalmente, mediante análisis termogravimétrico, aplicables a los modelos desarrollados, para el caso concreto del sorbente disponible.3- Se han modelizado matemáticamente los posibles reactores que pueden emplearse en la eliminación del compuesto H2S de este gas de gasificación, especialmente los reactores de lecho fluidizado de burbujeo, ya que poseen muy buenas cualidades de homogeneidad de temperatura y concentraciones. Se ha realizado el estudio de sensibilidad a las variaciones de los parámetros de funcionamiento. 4- Se ha construido una planta experimental a pequeña escala que ha permitido probar el sorbente con garantías en los resultados, para lo que se la ha dotado de los elementos de control y análisis de gas necesarios. 5- Se han realizado un número de experimentos suficiente para estudiar el comportamiento del sorbente en estudio, y para la obtención de datos experimentales que han permitido la validación de los diferentes modelos desarrollados.6- Se han obtenido las siguientes conclusiones resumidas:6.1 Se ha obtenido la cinética propia de la reacción gas-sólido no catalítica del sistema estudiado, viendo la influencia de la composición del gas en la velocidad de reacción. La cinética de primer orden describe adecuadamente los procesos de absorción y regeneración, habiéndose obtenido los parámetros cinéticos correspondientes. 6.2 Utilizando los modelos cinéticos desarrollados se proponen los valores de las características estructurales que optimizarían el comportamiento del sólido, en cuanto a su capacidad de retención de contaminante sulfurado: Porosidad no superior al 30% y área superficial de alrededor de 25 m2/g (frente a los valores actuales del 50%y 8,93 m2/g).6.3 El análisis termogravimétrico ha permitido identificar y cuantificar los valores de los diferentes parámetros que intervienen en la reacción gas-sólido: el coeficiente de reacción intrínseca superficial, la difusividad del gas en la capa de sólido formado, y el coeficiente de transferencia de masa gas-sólido. Asimismo las pruebas experimentales realizadas han puesto de manifiesto la influencia de la composición del gas en la cinética de reacción. 6.4 El equipo piloto de reacción experimental a pequeña escala, capaz de operar a alta temperatura y presión, ha permitido la validación de los modelos desarrollados del sistema de desulfurización, demostrándose que son una herramienta adecuada para su estudio, tanto para diseño, como en operación y control avanzado. Como posible continuación se presentan las siguientes posibilidades en la tarea de modelización: Estudiar modelos más precisos basados en ecuaciones de continuidad multifásicas, para su aplicación en sistemas de computación de alto rendimiento, o bien desarrollar modelos basados en reglas lógicas. En cuanto al desarrollo del sorbente, se pone de manifiesto la necesidad de continuar en su desarrollo para alcanzar los valores de las características señaladas. / OF THE THESISThis thesis is a contribution to the development of a new method of synthesis gas purification in IGCC plants, that make possible a further increase of the energy efficiency, and with this to reduce the emission of greenhouse gas to the atmosphere. It is studied a regenerative absorption in metallic oxides, capable of the elimination of the pollutants from the high-temperature gas, but taking advantage of the energy contents associated with the high temperature process streams, which is lost in the purification by wet route. The objectives and conclusions reached in the development of the thesis work are summarized below:1- The study of the kinetics of the purification reactions of the synthesis gas, non catalytic absorption reactions, with solid deposition. An exhaustive study has been carried out, to obtain some gas-solid reaction models that envisage a great number of possibilities. It has been created a simulation tool with a reduced number of restrictions that makes possible its use with any reaction that involves changes in the structure of the solid thus ensuring generality and independence of a given type of sorbent.2- The kinetic parameters have been obtained by thermogravimetric analysis for the concrete case of the available sorbent to be used in the testing of the developed models. 3- Appropriated type of reactors that can be employed in the elimination of the H2S compound of the gas contemplated have been identified and modeled. Special attention has been given to the bubbling fluidized bed reactors, since they possess very good properties of temperature and concentrations homogeneity. It has been accomplished the sensibility study to the variations of the operation parameters.4- An experimental bubbling fluidized bed reactor plant at bench-scale has been built that has permitted to extract the data from the selected sorbent with guarantees in the results.5- A sufficient number of experiments to study the behaviour of the selected sorbent under study have been accomplished successfully, and the experimental data obtained have permitted the validation of the different developed models.6- The specific conclusions reached are: 6.1. The study of the no-catalytic gas-solid reaction of the system studied shows that kinetics of first order describe adequately the absorption and regeneration processes.6.2. The accomplished experimental tests have shown the influence of the composition of the gas in the kinetics mechanism. The kinetic parameters are very dependent of the composition of the gas, not only of the reactive species, specially of the components that determine the reducing power.6.3. The thermogravimetric analysis has permitted to identify the values of the different parameters that appear in the gas reaction-solid: the coefficient of superficial intrinsic reaction, the diffusivity of the gas in the formed solid layer, and the gas-solid mass transfer coefficient.6.4. Using the developed kinetic models, the values of the structural characteristics that would optimise the behaviour of the solid are proposed, concerning its capacity of retention of sulfured pollutant: Porosity not superior to 30% and superficial area of about 25 m2 / g (as compared to the current values of the 50% and 8,93 m2 / g).6.5. The experimental small scale BFB pilot plant, capable of operating at high-temperature and pressure, has permitted the validation of the developed models for the desulphurisation system. The models developed have demonstrated that they are an adequate tool for the study, design, as well as the operation and advanced control of the system under study. As possible continuation of this thesis work in the modelization task the following is indicated: To study more accurate models based on fundamental multiphasic continuity equations, or else to develop models based on logic rules. With respect to development of the sorbent, the need of continuing in its development to reach the values of the indicated characteristics is shown.

This thesis deals with the possibility of using secondary raw materials from the energy industry especially the solid residues of high temperature combustion of coal. These materials should be now seen as a material with wide usage especially in the construction industry. One possibility of their usage is a replacement of binding parts in floor systems. The aim is to find the optimal composition of the mixture, which fits all the technical requirements and at the same time reduces the cost of its production. An advanced methods of powder X-ray diffraction analysis, particle size laser diffraction analysis and X-ray fluorescence analysis were used to determine the raw materials. Based on these analysis the experiments were designed focusing on the mechanical properties, the observation of the evolution of hydration’s heat in prepared mixtures and their time of setting and hardening.

The current usage of both classical and fluid combustion ashes is not sufficient and they are deposited in large quantities. The focus of this master´s thesis is to determine and verify some possibilities of their suitable applications in construction industry, specifically as the alternative aggregates for concrete. After the performed analysis several systems based on both classical and fluid combustion ashes have been proposed. Portland cement and hydrated lime were used as admixtures and binding properties of fluid combustion ashes were also tested. The most important properties were compressive strength and bulk density. The aim was to appropriate an optimal ratio between the addition of modifying substance and resulting strength of prepared aggregate in order to correspond to standards for aggregates for concrete.