Submitted by Silvana Teresinha Dornelles Studzinski (sstudzinski) on 2016-07-14T12:51:11Z No. of bitstreams: 1 Gabriel Cristiano Kuhn_.pdf: 1527987 bytes, checksum: dd028ed9d9ded68e948299bcc1bfb746 (MD5) / Made available in DSpace on 2016-07-14T12:51:11Z (GMT). No. of bitstreams: 1 Gabriel Cristiano Kuhn_.pdf: 1527987 bytes, checksum: dd028ed9d9ded68e948299bcc1bfb746 (MD5) Previous issue date: 2016-04-27 / FAPERGS - Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul / Válvula L é um tubo em forma de L destinado a conduzir partículas sólidas entre dois reservatórios. Este dispositivo usa injeção de um fluido e a sua geometria para o controle da vazão dos sólidos. A aplicação deste tipo de válvula não mecânica se dá em processos que visam o transporte de partículas, como linhas de transporte pneumático e reatores de leito circulante. O objetivo deste trabalho é desenvolver uma correlação para a vazão mássica de sólidos através da análise dos números adimensionais, calculados com base em variáveis do processo, e dados experimentais. Com uma correlação mais precisa torna-se mais fácil o controle e o projeto de uma válvula L. Este estudo desconsidera a influência dos reatores, levando em conta apenas a influência da geometria da válvula, a variação da injeção de ar e as propriedades das partículas. A bancada de ensaios foi projetada com duas válvulas L (diâmetros de 34 e 70 mm) feitas de acrílico. Foram utilizadas esferas de vidro (diâmetro Sauter 0,8 mm, massa específica efetiva 1580 kg/m3, grupo D da classificação Geldart), conduzidas por ar comprimido. Aplicando-se o teorema de PI de Buckingham às variáveis importantes do processo, três números adimensionais foram obtidos. Após uma bateria de testes, estes números adimensionais foram calculados para várias condições de ensaios. Com base nos dados experimentais, obteve-se uma equação de ajuste e uma correlação para o fluxo de sólidos. Calculou-se seis correlações, porém é possível dizer que apenas três descrevem o processo, mesmo que com alguma incerteza. Para as válvulas de 34 mm foi possível observar a máxima taxa de sólidos, ou seja, qualquer incremento na vazão injetada resulta em uma diminuição do escoamento de sólidos. / L valve is a right angled, L shaped pipe applied to transfer solids between two vessels. The device uses gas injection and pipe geometry for controlling the flow of particulate solids. This kind of non-mechanical valve is used in processes as pneumatic transport lines and circulating fluidized beds. This study aims to develop a new correlation to the solids mass flow rate through dimensional analysis, experimental data and equation fitting. An accurately way to estimate the flow of solids makes easier the valve design and control. This study does not consider the influence of the reactors that an L valve connect, in other words, this approach is limited to the influence of L valve geometry, gas injection and particle properties. A test section was built, comprising two valve diameters (acrylic pipes of 34 and 70 mm). Glass beads will be used as solids (Sauter diameter 0.8 mm, bulk density 1580 kg/m3, group D of Geldart classification) conveyed by air. Dimensionless numbers were calculated (by Buckingham PI theorem) from the variables of the process, then an experimental program was done. Based on experimental data, π_1, π_2 and π_3 values were calculated for various test conditions. Based on the experimental data, an equation fit and a correlation to the solids mass flow rate were obtained. Six correlation were calculated but only three are able to describe the L valve process with a minimum accuracy. Maximum solids flow were achieved for 34 mm L valve, in other words, if aeration rate is increased beyond this point, solids flow decreases.

La combustion en boucle chimique (CLC) est une nouvelle technologie prometteuse, qui implique la séparation inhérente du dioxyde de carbone (CO2) avec une perte minimale d'énergie. Un transporteur d'oxygène est utilisé pour le transfert de l'oxygène en continu du "réacteur air" vers le "réacteur fuel" où l'oxygène est apporté au combustible. Ainsi, le contact direct entre l'air et le combustible est évité. Le gaz résultant est riche en CO2 et n'est pas dilué avec de l'azote. Le transporteur d'oxygène réduit est ensuite transporté vers le "réacteur air" afin d'être ré-oxydé, formant ainsi une boucle chimique.Ce manuscrit présente des études conduites en utilisant une nouvelle configuration de CLC de 10 kWth construite pour étudier une large gamme de conditions opératoires. Cette unité met en oeuvre le concept des lits fluidisés interconnectés en utilisant des vannes-en-L pour contrôler le débit de solide et des siphons pour minimiser les fuites de gaz. L'hydrodynamique de la circulation de solide a été étudiée sur une maquette froide et un pilote chaud. Un modèle de la circulation du solide a ensuite été développé sur le principe du bilan de pression.L'hydrodynamique de la phase gaz dans le réacteur a été étudiée expérimentalement en utilisant la distribution des temps de séjour (DTS). Un modèle hydrodynamique a été développé sur le principe du lit fluidisé bouillonnant à deux phases. La combustion du méthane a été étudiée avec NiO/NiAl2O4 comme transporteur d'oxygène. De bonnes performances de combustion et de captage de CO2 ont été atteintes. Un modèle de réacteur a été finalement mis au point en utilisant le modèle hydrodynamique du lit fluidisé bouillonnant développé précédemment et en adaptant un schéma réactionnel à cette configuration / Chemical looping combustion (CLC) is a promising novel combustion technology involving inherent separation of carbon dioxide with minimum energy penalty. An oxygen carrier is used to continuously transfer oxygen from the air reactor to the fuel reactor where the oxygen is delivered to burn the fuel. Consequently, direct contact between the air and the fuel is prevented. The resulting flue gas is rich in CO2 without N2 dilution. The reduced oxygen carrier is then transported back to the air reactor for re-oxidation purposes, hence forming a chemical loop.This dissertation presents studies conducted on a novel 10 kWth CLC configuration built to investigate a wide range of conditions. The system employs concept of interconnected bubbling fluidized beds using L-valves to control solid flow rate and loop-seals to maximize gas tightness. Hydrodynamics of solid circulation was investigated with a cold flow prototype and a high temperature pilot plant in a wide temperature range. A solid circulation model was developed based on the experimental results using the pressure balance principle. Hydrodynamic of the gas phase in the reactors was investigated through RTD studies. A hydrodynamic model was then developed based on the two phase model of bubbling fluidized beds. Methane Combustion was experimentally studied in the pilot plant using NiO/NiAl2O4 oxygen carriers. Good combustion performances and CO2 capture efficiency were achieved. A reactor model was finally developed using the previously developed hydrodynamic model of bubbling fluidized bed and adapting a reaction scheme