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This thesis investigates the application of latent variable methods to three combustion processes. Multivariate analysis of flame images and process data is performed to predict important quality parameters and monitor flame stability. The motivation behind this work is to decrease operational costs and greenhouse gases in these energy intensive processes. The three combustion processes studied are a lime kiln, a basic oxygen furnace and a coal-fired boiler. In lime kiln operation, the main goal is to stabilize final product temperature in order to reduce fouling and energy costs. Due to long process dynamics, prediction of product temperature is required at least one hour in advance for potential use in a control scheme. Several methods for extracting features from flame images were investigated for the prediction of the temperature. The best method is then combined with process data in a PLS model that also incorporates dynamic information. The analysis revealed that prediction one hour into the future is successful using latent variable methods. In the basic oxygen furnace analysis, the main goal is to predict end-point carbon of the batch process. Termination of the batch as soon as the desired carbon is attained reduces oxygen consumption and thus operational cost. Traditional image analysis is used to identify a constant field of view in the flame images. Multivariate image feature extraction methods were then used in combination with process data to successfully predict the final carbon content of the heat. The coal-fired boiler analysis focuses on monitoring of flame stability at different production and air to fuel levels of the boiler. Prediction of energy efficiency and off-gas chemistry from flame images is also investigated. An unexpected result was the ability to use the installed cameras for localized fouling monitoring. This thesis showed that the use of multivariate analysis of flame images and process data in combustion process is very promising. / Thesis / Master of Applied Science (MASc)

No / This paper presents the development and implementation of an Analytical Target Cascading (ATC) Multi-disciplinary Design Optimisation (MDO) framework for the steady state engine calibration optimisation problem. The case is made that the ATC offers a convenient framework for the engine calibration optimisation problem based on steady state engine test data collected at specified engine speed / load points, which is naturally structured on 2 hierarchical levels: the ‘Global’ level, associated with performance over a drive cycle, and ‘Local’ level, relating to engine operation at each speed / load point. The case study of a diesel engine was considered to study the application of the ATC framework to a calibration optimisation problem. The paper describes the analysis and mathematical formulation of the diesel engine calibration optimisation as an ATC framework, and its Matlab implementation with gradient based and evolutionary optimisation algorithms. The results and performance of the ATC are discussed comparatively with the benchmark steady state solution for the engineering calibration of the diesel engine. The main conclusion from this research is that ATC optimisation framework offers an effective approach for engine calibration, with a potential to deliver significant fuel economy benefits. Further advantages of the ATC framework is that it is flexible and scalable to the complexity of the calibration problem, and enables calibrator preference to be incorporated a priori in the optimisation problem formulation, delivering important time saving for the overall calibration development process.

A busca de uma melhor compreensão dos ciclos químicos que ocorrem na atmosfera de Titan, um dos satélites naturais de Saturno, tem posto em relevância a importância de reações químicas envolvendo nitrogênio atômico e hidrocarbonetos, principalmente o radical metila. Além desta ênfase astroquìmica, essa reação tem também um papel importante no estudo da decomposição de metano em plasma pós-descarga de nitrogênio e no entendimento de processos de combustão. Neste trabalho, dando continuidade a estudos teóricos envolvendo reações de espécies atômicas com hidrocarbonetos realizados por este grupo e utilizando o estado da arte em termos de cálculos de estrutura eletrônica, realizou-se uma ampla investigação da superfície tripleto de energia potencial 3[H3, C, N] com ênfase nos aspectos estruturais, energéticos e espectroscópicos dos pontos estacionários e na cinética global da reação. Nesta superfície de energia potencial, foram caracterizados 7 pontos estacionários, sendo 3 estados de transição e 4 mínimos. No melhor nível de cálculo, CCSD(T)/CBS, o mínimo global corresponde à formação do radical metilnitreno, 71,01 kcal/mol mais estável do que o canal de entrada N(4S) + CH3 (2A2\"). Entretanto, via caminhos distintos, a reação prossegue formando H2CN + H como o principal produto, resultado esse que não confirma uma suposição anterior de que HCN seria o produto principal. No aspecto cinético, verificou-se que a etapa determinante da reação é regida pelo canal de entrada bimolecular, sem barreira, e que o valor para a constante de velocidade global, na melhor descrição deste trabalho, de 1,93 x 10-10 cm3 molécula?1 s-1, é bem superior à de estudo teórico anterior. Além da boa concordância com dados experimentais, nossos resultados também mostram um aumento da constante de velocidade com a temperatura, o que não foi previsto nesse estudo anterior. / The search for a better understanding of chemical cycles in Titan´s atmosphere, one of Saturn´s largest natural satellite, has emphasized the importance of chemical reactions between atomic nitrogen and hydrocarbons, especially methyl radical. Besides this astrochemical relevance, this reaction also plays a key role in the study of methane decomposition in after-glow nitrogen plasma, and in combustion processes. In this work, as another step towards theoretical studies of reactions involving atomic species with hydrocarbons carried out by this group, and using state-of-the-art electronic structure calculations, a wide investigation of the triplet potential energy surface 3[H3, C, N] was made with emphasis on structural, energetic, and spectroscopic aspects of the stationary points, and on the global kinetic description of the reaction. In this potential energy surface, 7 stationary points were characterized: 3 transition states and 4 minima. In our best description, CCSD(T)/CBS, the global minimum corresponds to the formation of the methylnitrene radical, 71.01 kcal/mol more stable than the entrance channel N(4S) + CH3 (2A2\"). However, by different paths, the reaction proceeds leading to the formation of H2CN + H as the major product, a result that does not confirm a previous supposition that HCN would be the major product. Kinetically, we have shown that the rate determining step is the barrierless bimolecular collision of CH3 and N(4S), and that the global rate constant, in the best estimate of this work, 1.93 x 10-10 cm3 molecule-1 s-1, is well superior to that of a previous theoretical study. Besides the good agreement with the experimental data, our results also show an increase of the rate constant with the temperature, a result not predicted by that previous study.

A busca de uma melhor compreensão dos ciclos químicos que ocorrem na atmosfera de Titan, um dos satélites naturais de Saturno, tem posto em relevância a importância de reações químicas envolvendo nitrogênio atômico e hidrocarbonetos, principalmente o radical metila. Além desta ênfase astroquìmica, essa reação tem também um papel importante no estudo da decomposição de metano em plasma pós-descarga de nitrogênio e no entendimento de processos de combustão. Neste trabalho, dando continuidade a estudos teóricos envolvendo reações de espécies atômicas com hidrocarbonetos realizados por este grupo e utilizando o estado da arte em termos de cálculos de estrutura eletrônica, realizou-se uma ampla investigação da superfície tripleto de energia potencial 3[H3, C, N] com ênfase nos aspectos estruturais, energéticos e espectroscópicos dos pontos estacionários e na cinética global da reação. Nesta superfície de energia potencial, foram caracterizados 7 pontos estacionários, sendo 3 estados de transição e 4 mínimos. No melhor nível de cálculo, CCSD(T)/CBS, o mínimo global corresponde à formação do radical metilnitreno, 71,01 kcal/mol mais estável do que o canal de entrada N(4S) + CH3 (2A2\"). Entretanto, via caminhos distintos, a reação prossegue formando H2CN + H como o principal produto, resultado esse que não confirma uma suposição anterior de que HCN seria o produto principal. No aspecto cinético, verificou-se que a etapa determinante da reação é regida pelo canal de entrada bimolecular, sem barreira, e que o valor para a constante de velocidade global, na melhor descrição deste trabalho, de 1,93 x 10-10 cm3 molécula?1 s-1, é bem superior à de estudo teórico anterior. Além da boa concordância com dados experimentais, nossos resultados também mostram um aumento da constante de velocidade com a temperatura, o que não foi previsto nesse estudo anterior. / The search for a better understanding of chemical cycles in Titan´s atmosphere, one of Saturn´s largest natural satellite, has emphasized the importance of chemical reactions between atomic nitrogen and hydrocarbons, especially methyl radical. Besides this astrochemical relevance, this reaction also plays a key role in the study of methane decomposition in after-glow nitrogen plasma, and in combustion processes. In this work, as another step towards theoretical studies of reactions involving atomic species with hydrocarbons carried out by this group, and using state-of-the-art electronic structure calculations, a wide investigation of the triplet potential energy surface 3[H3, C, N] was made with emphasis on structural, energetic, and spectroscopic aspects of the stationary points, and on the global kinetic description of the reaction. In this potential energy surface, 7 stationary points were characterized: 3 transition states and 4 minima. In our best description, CCSD(T)/CBS, the global minimum corresponds to the formation of the methylnitrene radical, 71.01 kcal/mol more stable than the entrance channel N(4S) + CH3 (2A2\"). However, by different paths, the reaction proceeds leading to the formation of H2CN + H as the major product, a result that does not confirm a previous supposition that HCN would be the major product. Kinetically, we have shown that the rate determining step is the barrierless bimolecular collision of CH3 and N(4S), and that the global rate constant, in the best estimate of this work, 1.93 x 10-10 cm3 molecule-1 s-1, is well superior to that of a previous theoretical study. Besides the good agreement with the experimental data, our results also show an increase of the rate constant with the temperature, a result not predicted by that previous study.