Yes / In this work, the performance of oxidative desulfurization (ODS) of dibenzothiophene (DBT) in light gas oil (LGO) is evaluated with a homemade manganese oxide (MnO2/γ-Al2O3) catalyst. The catalyst is prepared by Incipient Wetness Impregnation (IWI) method with air under moderate operating conditions. The effect of different reaction parameters such as reaction temperature, liquid hour space velocity and initial concentration of DBT are also investigated experimentally. Developing a detailed and a validated trickle bed reactor (TBR) process model that can be employed for design and optimization of the ODS process, it is important to develop kinetic models for the relevant reactions with high accuracy. Best kinetic model for the ODS process taking into account hydrodynamic factors (mainly, catalyst effectiveness factor, catalyst wetting efficiency and internal diffusion) and the physical properties affecting the oxidation process is developed utilizing data from pilot plant experiments. An optimization technique based upon the minimization of the sum of the squared error between the experimental and predicted composition of oxidation process is used to determine the best parameters of the kinetic models. The predicted product conversion showed very good agreement with the experimental data for a wide range of the operating condition with absolute average errors less than 5%.

No description available.

Yes / Batch oxidative desulfurization (ODS) process is investigated here for the removal sulfur compound from light naphtha using homemade new nano-catalyst. The catalyst is made of manganese dioxide supported on zeolite nanoparticles which shows an excellent catalytic performance with good impregnation, high activity, good pore size distribution and larger surface area. Different reaction temperature, time and initial sulfur concentration are used to have a deeper insight of the process. The experimental results reveal that the conversion of sulfur compound is increased by increasing the initial sulfur concentration, the reaction temperature and batch time. A mathematical model of the process is developed and validated using the experimental data within gPROMS software with high accuracy. The validated model (errors less than 5% between experimental and predicted results) is then utilized to obtain the optimal operation conditions of the process giving maximum conversion of sulfur (higher than 99%) resulting in an environmentally friendly fuel.

Thermophysical characterization of anisotropic composite materials is extremely important in the control of today fabrication processes and in the prediction of structure failure due to thermal stresses. Accuracy in the estimation of the thermal properties can be improved if the experiments are designed carefully. However, on one hand, the typically used parametric study for the design optimization is tedious and time intensive. On the other hand, commonly used gradient-based estimation methods show instabilities resulting in nonconvergence when used with models that contain correlated or nearly correlated parameters. The objectives of this research were to develop systematic and reliable methodologies for both Experimental Design Optimization (EDO) used for the determination of thermal properties, and Simultaneous Parameter Estimation (SPE). Because of their advantageous features, Genetic Algorithms (GAs) were investigated for use as a strategy for both EDO and SPE. The EDO and SPE approaches used involved the maximization of an optimality criterion associated with the sensitivity matrix of the unknown parameters, and the minimization of the ordinary least squares error, respectively. Two versions of a general-purpose genetic-based program were developed: one is designed for the analysis of any EDO / SPE problems for which a mathematical model can be provided, while the other incorporates a control-volume finite difference scheme allowing for the practical analysis of complex problems. The former version was used to illustrate the genetic performance on the optimization of a difficult mathematical test function. Two test cases previously solved in the literature were first analyzed to demonstrate and assess the GA-based {EDO/SPE} methodology. These problems included the optimization of one and two dimensional designs for the estimation at ambient temperature of two and three thermal properties, respectively (effective thermal conductivity parallel and perpendicular to the fibers plane and effective volumetric heat capacity), of anisotropic carbon/epoxy composite materials. The two dimensional case was further investigated to evaluate the effects of the optimality criterion used for the experimental design on the accuracy of the estimated properties. The general-purpose GA-based program was then successively applied to three advanced studies involving the thermal characterization of carbon/epoxy anisotropic composites. These studies included the SPE of successively three, seven and nine thermophysical parameters, with for the latter case, a two dimensional EDO with seven experimental key parameters. In two of the three studies, the parameters were defined to represent the dependence of the thermal properties with temperature. Finally, the kinetic characterization of the curing of three thermosetting materials (an epoxy, a polyester and a rubber compound) was accomplished resulting in the SPE of six kinetic parameters. Overall, the GA method was found to perform extremely well despite the high degree of correlation and low sensitivity of many parameters in all cases studied. This work therefore validates the use of GAs for the thermophysical characterization of anisotropic composite materials. The significance in using such algorithms is not only the solution to ill-conditioned problems but also, a drastically cost savings in both experimental and time expenses as they allow for the EDO and SPE of several parameters at once. / Ph. D.

A reoxigenação de água residuária é tratada na literatura técnica de maneira análoga à reoxigenação na água limpa; os efeitos do consumo de oxigênio pela população bacteriana ativa são quantificados pela introdução dos parâmetros alfa e beta. Alfa corrige o coeficiente volumétrico de transferência de massa do oxigênio e beta corrige a concentração de saturação do oxigênio dissolvido na água. Com o presente estudo pretende-se tornar explícitos os parâmetros cinéticos envolvidos no processo, de modo a fornecer base conceitual para um melhor entendimento do fenômeno. A pesquisa é feita a partir de trabalho experimental, seguido de modelagem matemática conceitual. No entanto, no lugar dos microrganismos como sumidouro de oxigênio dissolvido foi utilizado o borbulhamento sub-superficial de gás nitrogênio, em processo de stripping. Um processo físico, portanto, substitui o processo bioquímico no papel de retirar o oxigênio dissolvido no seio líquido. O modelo matemático proposto ajustou-se bem aos dados experimentais, sendo que a sua validação pôde ser obtida através das análises estatísticas realizadas. / The reoxygenation in wastewater is seen in the technical literature in an analogous way as the reoxygenation of clean water. The effects of the oxygen consumed by active bacteria population are quantified with the introduction of the parameters alpha and beta. Alpha corrects for the volumetric mass transfer coefficient and beta corrects for the dissolved oxygen saturation concentration. The present research intends to make explicit the kinetic of the process, in order to supply conceptual support to a better understanding of the phenomenon. The research is done through experimental work, followed by conceptual, mathematical modeling. Stripping with nitrogen is used as an oxygen sink instead of microorganisms. Thus, a physical process replaces the biochemical process. The proposed mathematical model fitted well to the experimental data, and its validation could be obtained through the statistical analyses done.

Este trabalho apresenta uma nova abordagem experimental para determinar a reatividade de sistemas subcríticos. O método a ser apresentado utiliza o modelo da cinética subcrítica desenvolvido por Gandini e Salvatores e baseia-se apenas em grandezas medidas, tais como a taxa de contagem no detector, e nos parâmetros que surgem do ajuste dos mínimos quadrados APSD (Auto Power Spectral Density) e CPSD (Cross Power Spectral Density), não sendo necessário lidar com as quantidades de maior complexidade como a eficiência de detector. A única hipótese feita neste método foi que a fração efetiva de nêutrons atrasados e o tempo de geração de nêutrons prontos fossem independentes do nível de subcriticalidade do sistema. O método proposto foi aplicado nas medidas de reatividade de várias configurações subcríticas do reator IPEN/MB-01. Foram realizadas medidas da APSD e CPSD em diversos graus de subcriticalidade (até em torno de -7000 pcm). Nos dados das densidades espectrais foram feitos ajustes por meio do método de mínimos quadrados para obter a constante de decaimento pronto (α) e outras grandezas. Com a finalide de melhorar as estatísticas de contagem de nêutrons, fonte externa de nêutrons de Am-Be foi instalada próximo ao núcleo, além da fonte de partida. O método experimental proposto mostra claramente que, a teoria da cinética pontual clássica não descreve a reatividade medida. Em vez disso, a reatividade inferida a partir do modelo da cinética pontual clássica é próxima, em seus valores absolutos, ao índice de subcriticalidade (ζ) para um determinado arranjo das fontes do experimeno. A concordância dos resultados obtidos por MCNP5 e GPT-TORT, ambos utilizando os dados nucleares da biblioteca ENDF/B-VII.0, com os resultados experimentais correspondentes são de boa qualidade. / This work presents a new experimental approach to determine the reactivity levels of subcritical systems. The method employs the subcritical kinetic model developed by Gandini and Salvatores and it is based only on measured quantities such as counting rates of the detectors employed in the experiments and the parameters arising from the least squares fitting of the APSD (Auto Power Spectral Density) and CPSD (Cross Power Spectral Density). Detector efficiencies, quantity required in other procedures such as Neutron Source Multiplication (NSM) method, are not needed in the proposed method. The only hypothesis made in the method was the independence of the effective delayed neutron fraction and the prompt neutron generation time to the subcriticality level of the system. The proposed method was applied to measure the reactivity of several subcritical configurations of the IPEN/MB-01 reactor. Measurements of APSD and CPSD were performed in several degrees of subcriticality (up to around -7000 pcm). The spectral densities data were least squares fitted to get the prompt decay mode (α) and other quantities. Beside the startup source of the facility, an external neutron source of Am-Be was installed near the core in order to improve neutron counting statistics. The final experimental results are of good quality. The proposed experimental method shows clearly that the classical point kinetic theory cannot describe the measured reactivity. Instead, the reactivity inferred from this model follows closely the subcriticality index (ζ) for the source arrangements in the experiment. The agreement of the MCNP5 and GPT-TORT results, both with ENDF/B-VII.0 as the basic nuclear data library, when compared to the corresponding experimental ones was also good.

Un nanocalorimètre permet l'analyse thermique de très faibles quantités d'échantillons (quelques nanogrammes ou picogrammes), ainsi que l'étude de films minces dont l'épaisseur varie de quelques nanomètres à plus d'un micron. Les vitesses de chauffe et de refroidissement sont nettement plus élevées que celles réalisées avec une DSC classique : les vitesses de chauffe peuvent atteindre 103 à 106 K/s, par conséquent, les mesures réalisées avec ce type d'appareil sont très rapides (quelques millisecondes). Du fait de sa sensibilité élevée, des vitesses de chauffe rapides atteintes et de l'acquisition rapide des données, le nanocalorimètre peut être utilisé pour la caractérisation et la détection de quelques nanogrammes de matériaux énergétiques. Les objectifs de cette thèse sont d'une part de mettre au point une procédure de calibration des capteurs nanocalorimétriques (calibration de la température, de la puissance, de la masse du microcristal à analyser) et d'autre part de caractériser des matériaux énergétiques afin de pouvoir effectuer des analyses quantitatives en vue d'applications pour la détection d'explosifs. Les matériaux énergétiques étudiés sont des films de nitrocellulose, des cristaux de penthrite, d'hexogène (principal constituant du C4), de 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12- hexaazaisowurtzitane (Cl20), et des nano-cristaux d'explosifs. Le travail réalisé a montré qu'il est possible de rapidement différencier des explosifs par leurs températures de fusion, de décomposition et d'évaporation. Il est aussi possible de déterminer des paramètres cinétiques d'un cristal isolé d'explosif. / Calorimetry is one of the main techniques of thermal analysis. Most of physical or chemical modifications of material are associated with thermal effects whereby heat is absorbed (i.e., melting) or released (i.e., thermal decomposition). Typically, calorimetric experiments are performed with Differential Scanning Calorimetry (DSC), which measures the heat flux absorbed or released by the sample following the same temperature program as a reference material. In these experiments, measurements are typically carried out on a few milligrams of sample. However, for many applications one has to handle nanograms or even picograms of sample. One of such applications is relevant to studies of materials which can release a significant amount of energy during their decomposition (energetic materials). Calorimetry able to handle nanograms of sample could find potential applications in the field of explosives detection. Nanocalorimetry allows to heat small amounts of sample (a few nanograms to a few hundred picograms) at extreme heating rates, i.e. up to one million °C/s. The temperature increase can initiate several phenomena in energetic materials, therefore the calorimetry could be an appropriate technique to characterize and to detect energetic materials. The energetic materials used in this study are nitrocellulose (NC), hexogen (RDX), 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-ltexaazaisowurtzitane (CL-20) and penthrite (PETN). The manuscript presents our results on the nanocalorimeter calibration, on the thermal behaviour of the explosives studied with nanocalorimetry and also includes an evaluation of nanocalorimetry as a tool for explosives detection.

Um novo laboratório experimental desenvolvido para investigar a combustão de carvão em atmosferas de oxicombustão é descrito em detalhes na tese. Um reator ciclônico é utilizado para a combustão de carvões de baixo rank em condições de escoamento turbulento e com swirl, e operando em temperaturas similares às encontradas em câmaras de combustão industriais. Um sensor potenciométrico de oxigênio, instalado dentro do reator ciclônico, é utilizado para medir o consumo de oxigênio durante a combustão das amostras de carvão. Amostras de carvão com alto teor de cinzas, das minas do Leão e Bonito localizadas no sul do Brasil, e amostras de carvão linhito pré-seco (LTBK), da região da Lusácia, na Alemanha, foram submetidos à combustão em atmosferas de ar e de oxicombustão (O2/CO2/H2O). Os experimentos foram realizados em três temperaturas médias do gás de combustão: 1073, 1173 e 1273 K. Para as amostras do carvão LTBK, a oxicombustão foi composta com duas atmosferas de O2/CO2 sem vapor d’água (21/79 e 30/70) e três atmosferas de O2/CO2/H2O (30/60/10, 30/50/20 e 30/40/30) em base molar, enquanto para as amostras dos carvões Leão e Bonito, a oxicombustão foi composta com duas atmosferas de O2/CO2 (21/79 e 30/70). As amostras de carvão foram peneiradas para uma faixa de tamanho de partículas de 1250 a 2000 μm e 125 a 500 μm, e com massas de 1g e 3g. Em adição aos testes, amostras de char dos carvões Leão e LTBK foram preparadas para investigar o comportamento da combustão de suas matrizes carbonosas com diferentes níveis de matéria volátil. Primeiramente, a investigação da combustão do carvão é feita diretamente a partir das curvas de concentração de oxigênio medidas para a combustão das amostras de carvão LTBK submetidos às atmosferas de ar e oxicombustão com vapor d’água, conforme explicado no Capítulo 2 desta tese. Entretanto, devido ao grande número de experimentos realizados e a necessidade de entender a influência dos fatores, como temperatura e as composições das atmosferas oxidantes, e as interações entre esses fatores na combustão do carvão, a análise pela metodologia do Projeto de Experimentos (DoE) é aplicada nos experimentos, conforme detalhado no Capítulo 3. A reatividade dos carvões de baixo rank é investigada por meio do cálculo dos parâmetros cinéticos globais e dos coeficientes da taxa de reação de combustão do char, considerando a hipótese de um reator bem misturado, a ser verificada ao longo da investigação, conforme descrito no Capítulo 4. A partir da análise das curvas de concentração de oxigênio (Capítulos 2 e 3), os resultados mostram que a atmosfera de oxicombustão com 79% de CO2 (21/79, O2/CO2) aumenta o consumo de oxigênio para os carvões de alto teor de cinzas, Bonito e Leão, e para o carvão linhito com alto teor de voláteis (LTBK), devido à influência da reação de gaseificação do CO2 a partir de temperaturas acima de 1073 K. A partir da análise dos parâmetros cinéticos globais calculados para avaliar a reatividade dos carvões, os resultados mostram que a hipótese do reator bem misturado não é o suficiente para capturar a cinética da combustão do carvão por batelada no interior do reator ciclônico. A reatividade dos carvões investigados, através das constantes efetivas da taxa de reação, variando-se a composição da atmosfera oxidante, temperatura do gás de combustão, tamanho de partículas, massa da amostra e posição do sensor de oxigênio, têm influência do escoamento com swirl e seus termos advectivos e difusivos. / A novel laboratory facility designed to investigate coal oxy-fuel combustion is described in the present work. A cyclone chamber allows for the combustion of low-rank coal under turbulent conditions and swirling flows, covering a temperature range similar to those found on practical furnaces. A potentiometric oxygen sensor with oxide-ion conducting solid electrolytes, as stabilized zirconia, installed within the cyclone reactor, is used to measure the oxygen consumption during the combustion of coal samples. High ash coals samples, from Leão and Bonito mining sites located in South Brazil, and pre-dried lignite coal samples (LTBK), from the Lusatian region, in Germany, were burned under air and oxy-fuel (O2/CO2/H2O) atmospheres. Experiments were carried out at three average gas combustion temperatures: 1073, 1173 and 1273 K. For LTBK coal, oxy-fuel combustion was composed with two O2/CO2 atmospheres (21/79 and 30/70) and three O2/CO2/H2O atmospheres (30/60/10, 30/50/20 and 30/40/30) in molar basis, whereas for Leão and Bonito coals, the oxy-fuel combustion was composed with two O2/CO2 atmospheres (21/79 and 30/70). Coal samples were sieved to a size range of 1250 to 2000 μm and 125 to 500 μm and with 1g and 3g. In addition, char samples from Leão and lignite coals were prepared in order to investigate the combustion behavior of its carbon matrix for different levels of volatile matter. The investigation of coal combustion behavior is made firstly directly on the oxygen concentration curves measured for LTBK coal samples burned under air and oxy-fuel atmospheres with water vapor, as detailed in Chapter 2 of this thesis. However, due to the great number of experiments performed and the need to understand the influence of the factors, as temperature and atmosphere compositions, and the interactions between them on the coal combustion, the Design of Experiments (DoE) analysis is applied in the laboratory test facility, as developed in Chapter 3. The reactivity of low rank coals is assessed by means of global kinetic parameters and of char combustion reaction coefficients, under assumption of a well stirred reactor to be tested along the investigation, as described in Chapter 4. From the analysis of oxygen concentration curves (Chapter 2 and 3), results show that oxidizer oxy-fuel atmosphere with 79% CO2 (21/79, O2/CO2) increases the oxygen consumption for high ash coals, Bonito and Leão, and for pre-dried lignite coal, LTBK, due to the influence of CO2 gasification reaction on their coal combustion reactions from gas combustion temperatures higher than 1073 K. From the analysis of global kinetic parameters calculated to assess the coal reactivity, the results show that the hypothesis of a well stirred reactor is not enough to capture the kinetic involved in coal combustion burned in batch mode within the cyclone reactor. The coal reactivity investigated with the effective reaction rate constants for different oxidizer atmospheres, gas combustion temperatures, particle diameters, sample masses and oxygen sensor position, is influenced by the swirling flow with its advective and diffusive terms.

Um novo laboratório experimental desenvolvido para investigar a combustão de carvão em atmosferas de oxicombustão é descrito em detalhes na tese. Um reator ciclônico é utilizado para a combustão de carvões de baixo rank em condições de escoamento turbulento e com swirl, e operando em temperaturas similares às encontradas em câmaras de combustão industriais. Um sensor potenciométrico de oxigênio, instalado dentro do reator ciclônico, é utilizado para medir o consumo de oxigênio durante a combustão das amostras de carvão. Amostras de carvão com alto teor de cinzas, das minas do Leão e Bonito localizadas no sul do Brasil, e amostras de carvão linhito pré-seco (LTBK), da região da Lusácia, na Alemanha, foram submetidos à combustão em atmosferas de ar e de oxicombustão (O2/CO2/H2O). Os experimentos foram realizados em três temperaturas médias do gás de combustão: 1073, 1173 e 1273 K. Para as amostras do carvão LTBK, a oxicombustão foi composta com duas atmosferas de O2/CO2 sem vapor d’água (21/79 e 30/70) e três atmosferas de O2/CO2/H2O (30/60/10, 30/50/20 e 30/40/30) em base molar, enquanto para as amostras dos carvões Leão e Bonito, a oxicombustão foi composta com duas atmosferas de O2/CO2 (21/79 e 30/70). As amostras de carvão foram peneiradas para uma faixa de tamanho de partículas de 1250 a 2000 μm e 125 a 500 μm, e com massas de 1g e 3g. Em adição aos testes, amostras de char dos carvões Leão e LTBK foram preparadas para investigar o comportamento da combustão de suas matrizes carbonosas com diferentes níveis de matéria volátil. Primeiramente, a investigação da combustão do carvão é feita diretamente a partir das curvas de concentração de oxigênio medidas para a combustão das amostras de carvão LTBK submetidos às atmosferas de ar e oxicombustão com vapor d’água, conforme explicado no Capítulo 2 desta tese. Entretanto, devido ao grande número de experimentos realizados e a necessidade de entender a influência dos fatores, como temperatura e as composições das atmosferas oxidantes, e as interações entre esses fatores na combustão do carvão, a análise pela metodologia do Projeto de Experimentos (DoE) é aplicada nos experimentos, conforme detalhado no Capítulo 3. A reatividade dos carvões de baixo rank é investigada por meio do cálculo dos parâmetros cinéticos globais e dos coeficientes da taxa de reação de combustão do char, considerando a hipótese de um reator bem misturado, a ser verificada ao longo da investigação, conforme descrito no Capítulo 4. A partir da análise das curvas de concentração de oxigênio (Capítulos 2 e 3), os resultados mostram que a atmosfera de oxicombustão com 79% de CO2 (21/79, O2/CO2) aumenta o consumo de oxigênio para os carvões de alto teor de cinzas, Bonito e Leão, e para o carvão linhito com alto teor de voláteis (LTBK), devido à influência da reação de gaseificação do CO2 a partir de temperaturas acima de 1073 K. A partir da análise dos parâmetros cinéticos globais calculados para avaliar a reatividade dos carvões, os resultados mostram que a hipótese do reator bem misturado não é o suficiente para capturar a cinética da combustão do carvão por batelada no interior do reator ciclônico. A reatividade dos carvões investigados, através das constantes efetivas da taxa de reação, variando-se a composição da atmosfera oxidante, temperatura do gás de combustão, tamanho de partículas, massa da amostra e posição do sensor de oxigênio, têm influência do escoamento com swirl e seus termos advectivos e difusivos. / A novel laboratory facility designed to investigate coal oxy-fuel combustion is described in the present work. A cyclone chamber allows for the combustion of low-rank coal under turbulent conditions and swirling flows, covering a temperature range similar to those found on practical furnaces. A potentiometric oxygen sensor with oxide-ion conducting solid electrolytes, as stabilized zirconia, installed within the cyclone reactor, is used to measure the oxygen consumption during the combustion of coal samples. High ash coals samples, from Leão and Bonito mining sites located in South Brazil, and pre-dried lignite coal samples (LTBK), from the Lusatian region, in Germany, were burned under air and oxy-fuel (O2/CO2/H2O) atmospheres. Experiments were carried out at three average gas combustion temperatures: 1073, 1173 and 1273 K. For LTBK coal, oxy-fuel combustion was composed with two O2/CO2 atmospheres (21/79 and 30/70) and three O2/CO2/H2O atmospheres (30/60/10, 30/50/20 and 30/40/30) in molar basis, whereas for Leão and Bonito coals, the oxy-fuel combustion was composed with two O2/CO2 atmospheres (21/79 and 30/70). Coal samples were sieved to a size range of 1250 to 2000 μm and 125 to 500 μm and with 1g and 3g. In addition, char samples from Leão and lignite coals were prepared in order to investigate the combustion behavior of its carbon matrix for different levels of volatile matter. The investigation of coal combustion behavior is made firstly directly on the oxygen concentration curves measured for LTBK coal samples burned under air and oxy-fuel atmospheres with water vapor, as detailed in Chapter 2 of this thesis. However, due to the great number of experiments performed and the need to understand the influence of the factors, as temperature and atmosphere compositions, and the interactions between them on the coal combustion, the Design of Experiments (DoE) analysis is applied in the laboratory test facility, as developed in Chapter 3. The reactivity of low rank coals is assessed by means of global kinetic parameters and of char combustion reaction coefficients, under assumption of a well stirred reactor to be tested along the investigation, as described in Chapter 4. From the analysis of oxygen concentration curves (Chapter 2 and 3), results show that oxidizer oxy-fuel atmosphere with 79% CO2 (21/79, O2/CO2) increases the oxygen consumption for high ash coals, Bonito and Leão, and for pre-dried lignite coal, LTBK, due to the influence of CO2 gasification reaction on their coal combustion reactions from gas combustion temperatures higher than 1073 K. From the analysis of global kinetic parameters calculated to assess the coal reactivity, the results show that the hypothesis of a well stirred reactor is not enough to capture the kinetic involved in coal combustion burned in batch mode within the cyclone reactor. The coal reactivity investigated with the effective reaction rate constants for different oxidizer atmospheres, gas combustion temperatures, particle diameters, sample masses and oxygen sensor position, is influenced by the swirling flow with its advective and diffusive terms.

Este trabalho apresenta uma nova abordagem experimental para determinar a reatividade de sistemas subcríticos. O método a ser apresentado utiliza o modelo da cinética subcrítica desenvolvido por Gandini e Salvatores e baseia-se apenas em grandezas medidas, tais como a taxa de contagem no detector, e nos parâmetros que surgem do ajuste dos mínimos quadrados APSD (Auto Power Spectral Density) e CPSD (Cross Power Spectral Density), não sendo necessário lidar com as quantidades de maior complexidade como a eficiência de detector. A única hipótese feita neste método foi que a fração efetiva de nêutrons atrasados e o tempo de geração de nêutrons prontos fossem independentes do nível de subcriticalidade do sistema. O método proposto foi aplicado nas medidas de reatividade de várias configurações subcríticas do reator IPEN/MB-01. Foram realizadas medidas da APSD e CPSD em diversos graus de subcriticalidade (até em torno de -7000 pcm). Nos dados das densidades espectrais foram feitos ajustes por meio do método de mínimos quadrados para obter a constante de decaimento pronto (α) e outras grandezas. Com a finalide de melhorar as estatísticas de contagem de nêutrons, fonte externa de nêutrons de Am-Be foi instalada próximo ao núcleo, além da fonte de partida. O método experimental proposto mostra claramente que, a teoria da cinética pontual clássica não descreve a reatividade medida. Em vez disso, a reatividade inferida a partir do modelo da cinética pontual clássica é próxima, em seus valores absolutos, ao índice de subcriticalidade (ζ) para um determinado arranjo das fontes do experimeno. A concordância dos resultados obtidos por MCNP5 e GPT-TORT, ambos utilizando os dados nucleares da biblioteca ENDF/B-VII.0, com os resultados experimentais correspondentes são de boa qualidade. / This work presents a new experimental approach to determine the reactivity levels of subcritical systems. The method employs the subcritical kinetic model developed by Gandini and Salvatores and it is based only on measured quantities such as counting rates of the detectors employed in the experiments and the parameters arising from the least squares fitting of the APSD (Auto Power Spectral Density) and CPSD (Cross Power Spectral Density). Detector efficiencies, quantity required in other procedures such as Neutron Source Multiplication (NSM) method, are not needed in the proposed method. The only hypothesis made in the method was the independence of the effective delayed neutron fraction and the prompt neutron generation time to the subcriticality level of the system. The proposed method was applied to measure the reactivity of several subcritical configurations of the IPEN/MB-01 reactor. Measurements of APSD and CPSD were performed in several degrees of subcriticality (up to around -7000 pcm). The spectral densities data were least squares fitted to get the prompt decay mode (α) and other quantities. Beside the startup source of the facility, an external neutron source of Am-Be was installed near the core in order to improve neutron counting statistics. The final experimental results are of good quality. The proposed experimental method shows clearly that the classical point kinetic theory cannot describe the measured reactivity. Instead, the reactivity inferred from this model follows closely the subcriticality index (ζ) for the source arrangements in the experiment. The agreement of the MCNP5 and GPT-TORT results, both with ENDF/B-VII.0 as the basic nuclear data library, when compared to the corresponding experimental ones was also good.