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Nunes, Deivid Marques - One of the best experts on this subject based on the ideXlab platform.
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Estudo sobre o efeito de vibrações axiais sobre a formação e remoção de tortas de filtração gás-sólidos
Universidade Federal de Uberlândia, 2017Co-Authors: Nunes, Deivid MarquesAbstract:Com o intuito de tornar a operação de filtração de gases mais eficiente, o objetivo desse trabalho foi adaptar um sistema de filtração com motor vibrador acoplado axial ao fluxo gasoso que possibilitasse o desprendimento da torta de filtração sem a necessidade de parar a operação de filtração, além de avaliar a influências das frequências de vibração mecânica na formação das tortas quanto às forças de arraste no meio filtrante, espessuras das tortas, resistências específicas das tortas, porosidades das tortas em comparação com o sistema ausente de vibração. Foram utilizados como materiais particulados o polvilho doce, o talco puro e a rocha fosfática moída, a fim de verificar a influência da vibração em materiais particulados com diferentes morfologias e distribuição granulométrica. A velocidade de filtração superficial do fluxo gasoso foi de 10 cm/s, a uma vazão mássica de 0,183 g/s e queda de pressão máxima estabelecida de 10000 Pa. As porosidades das tortas de filtração foram determinadas por correlações encontradas na literatura. Os resultados mostraram que para as frequências de vibrações mecânicas de 12, 17 e 18 Hz influenciaram na estrutura da torta e em sua remoção para o material particulado rocha fosfática moída, cuja circularidade era de 0,60, causando a formação de tortas menos espessas, mais resistentes e menos porosas quando comparadas ao sistema estático. As forças de adesão desse material também foram maiores para as frequências de vibração que o sistema estático. Concluiu-se que as vibrações mecânicas causaram um empacotamento mais denso das partículas de rocha moída no meio filtrante. Já para o material particulado, o talco puro, cuja circularidade era de 0,67, as vibrações mecânicas tanto para o sistema independente quanto ao sistema intermitente proporcionam comportamentos semelhantes ao sistema estático, não sendo viável sua utilização. Para as partículas de polvilho doce, cuja circularidade se aproxima de um círculo perfeito, 0,98, para a frequência de vibração de 12 Hz independente possibilitou a formação de tortas com maiores espessuras, menores resistências específicas das tortas e maiores porosidades quando comparadas ao sistema estático, além de menor força de adesão quando comparadas ao sistema estático. Isso possivelmente estar relacionado ao surgimento de lacunas nas tortas e à distribuição das partículas nas camadas das tortas. Enfim, o sistema de vibração mecânica independente e intermitente não possibilitou o desprendimento das tortas de filtração, porém influenciou a estrutura de formação das tortas.Many studies related to the filtration of gases for the control and recovery of particulate materials have been developed with the aim of making the filtration system, both in the gas filtration operation as in the cleaning operation, more effective, with a longer useful life of the fabric filters and with greater ease of removal of cake filtration, tanking into account the currente laws regarding the emission of pollutants not environment and reduction of maintenance and operation costs. In this context, in order to make the gas filtration operation more efficient, the objective of this work was to adapt a filtration system with vibration motor coupled axially to the Gaseous flow that would allow the detachment of the filter cake without the need to stop the operation filtration, and to evaluate the influences of mechanical vibration frequencies in the formation of cakes as the forces of drag on the filter medium, the thickness of cakes filtration, specific resistance of cake, porosity of cake compared with the static system. The manioc starch powder, pure talcum powder and phosphate rock were used as particulates in order to verify the influence of vibration on particulates with different morphologies and granulometric distribution. The surface filtration velocity of the Gaseous Stream was 10 cm / s at a mass flow rate of 0.183 g / s and the maximum pressure drop was 10000 Pa. The porosities of the cake filtration were determined by correlations found in the literature. The results showed that the frequencies of mechanical vibration 12, 17 and 18Hz influenced the structure of the cake and its removal for the rock phosphate particulate material, whose circularity was of 0.60, causing a formation of thinner of cake filtrantion, more resistant cake filtration and less porous cake filtrantion when compared to the static system. As adhesion forces of material also higher for vibration frequencies than the static system. It was concluded that the mechanical vibrations caused a denser packing of the phosphate rock particles in the filter medium. As for the particulate material, pure talcum powder, , whose circularity was of 0.67, the mechanical vibrations to both the independent system and the intermittent system provide behavior similar to the static system, it is not feasible to use. For the particles of manioc starch, whose circularity approaches a perfect circle, 0.98, for the independent vibration frequency of 12 Hz allowed the formation of cake filtration with greater thicknesses, smaller specific resistances of the cake filtrantion and larger porosities when compared to the static system, as well as lower adhesion force when compared to the static system. This may be related to the appearance of gaps in the cake filtration and the distribution of the particles in the layers of the cake filtration. Finally, the system of independent and intermittent mechanical vibration did not allow the detachment of the filter cake, but influenced the structure of the cake formation
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Estudo sobre o efeito de vibrações axiais sobre a formação e remoção de tortas de filtração gás-sólidos
'EDUFU - Editora da Universidade Federal de Uberlandia', 2017Co-Authors: Nunes, Deivid MarquesAbstract:Many studies related to the filtration of gases for the control and recovery of particulate materials have been developed with the aim of making the filtration system, both in the gas filtration operation as in the cleaning operation, more effective, with a longer useful life of the fabric filters and with greater ease of removal of cake filtration, tanking into account the currente laws regarding the emission of pollutants not environment and reduction of maintenance and operation costs. In this context, in order to make the gas filtration operation more efficient, the objective of this work was to adapt a filtration system with vibration motor coupled axially to the Gaseous flow that would allow the detachment of the filter cake without the need to stop the operation filtration, and to evaluate the influences of mechanical vibration frequencies in the formation of cakes as the forces of drag on the filter medium, the thickness of cakes filtration, specific resistance of cake, porosity of cake compared with the static system. The manioc starch powder, pure talcum powder and phosphate rock were used as particulates in order to verify the influence of vibration on particulates with different morphologies and granulometric distribution. The surface filtration velocity of the Gaseous Stream was 10 cm / s at a mass flow rate of 0.183 g / s and the maximum pressure drop was 10000 Pa. The porosities of the cake filtration were determined by correlations found in the literature. The results showed that the frequencies of mechanical vibration 12, 17 and 18Hz influenced the structure of the cake and its removal for the rock phosphate particulate material, whose circularity was of 0.60, causing a formation of thinner of cake filtrantion, more resistant cake filtration and less porous cake filtrantion when compared to the static system. As adhesion forces of material also higher for vibration frequencies than the static system. It was concluded that the mechanical vibrations caused a denser packing of the phosphate rock particles in the filter medium. As for the particulate material, pure talcum powder, , whose circularity was of 0.67, the mechanical vibrations to both the independent system and the intermittent system provide behavior similar to the static system, it is not feasible to use. For the particles of manioc starch, whose circularity approaches a perfect circle, 0.98, for the independent vibration frequency of 12 Hz allowed the formation of cake filtration with greater thicknesses, smaller specific resistances of the cake filtrantion and larger porosities when compared to the static system, as well as lower adhesion force when compared to the static system. This may be related to the appearance of gaps in the cake filtration and the distribution of the particles in the layers of the cake filtration. Finally, the system of independent and intermittent mechanical vibration did not allow the detachment of the filter cake, but influenced the structure of the cake formation.Tese (Doutorado)Com o intuito de tornar a operação de filtração de gases mais eficiente, o objetivo desse trabalho foi adaptar um sistema de filtração com motor vibrador acoplado axial ao fluxo gasoso que possibilitasse o desprendimento da torta de filtração sem a necessidade de parar a operação de filtração, além de avaliar a influências das frequências de vibração mecânica na formação das tortas quanto às forças de arraste no meio filtrante, espessuras das tortas, resistências específicas das tortas, porosidades das tortas em comparação com o sistema ausente de vibração. Foram utilizados como materiais particulados o polvilho doce, o talco puro e a rocha fosfática moída, a fim de verificar a influência da vibração em materiais particulados com diferentes morfologias e distribuição granulométrica. A velocidade de filtração superficial do fluxo gasoso foi de 10 cm/s, a uma vazão mássica de 0,183 g/s e queda de pressão máxima estabelecida de 10000 Pa. As porosidades das tortas de filtração foram determinadas por correlações encontradas na literatura. Os resultados mostraram que para as frequências de vibrações mecânicas de 12, 17 e 18 Hz influenciaram na estrutura da torta e em sua remoção para o material particulado rocha fosfática moída, cuja circularidade era de 0,60, causando a formação de tortas menos espessas, mais resistentes e menos porosas quando comparadas ao sistema estático. As forças de adesão desse material também foram maiores para as frequências de vibração que o sistema estático. Concluiu-se que as vibrações mecânicas causaram um empacotamento mais denso das partículas de rocha moída no meio filtrante. Já para o material particulado, o talco puro, cuja circularidade era de 0,67, as vibrações mecânicas tanto para o sistema independente quanto ao sistema intermitente proporcionam comportamentos semelhantes ao sistema estático, não sendo viável sua utilização. Para as partículas de polvilho doce, cuja circularidade se aproxima de um círculo perfeito, 0,98, para a frequência de vibração de 12 Hz independente possibilitou a formação de tortas com maiores espessuras, menores resistências específicas das tortas e maiores porosidades quando comparadas ao sistema estático, além de menor força de adesão quando comparadas ao sistema estático. Isso possivelmente estar relacionado ao surgimento de lacunas nas tortas e à distribuição das partículas nas camadas das tortas. Enfim, o sistema de vibração mecânica independente e intermitente não possibilitou o desprendimento das tortas de filtração, porém influenciou a estrutura de formação das tortas
Martin Olazar - One of the best experts on this subject based on the ideXlab platform.
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kinetic modelling of pine sawdust combustion in a conical spouted bed reactor
Fuel, 2018Co-Authors: Juan F Saldarriaga, Roberto Aguado, Aitor Atxutegi, Javier Bilbao, Martin OlazarAbstract:Abstract A model has been proposed and validated for the prediction of biomass combustion rate in a conical spouted bed. The model couples the intrinsic kinetics for the process and the flow pattern of the Gaseous Stream in the unit. The kinetics is described based on a reaction scheme consisting in simultaneous devolatilization and combustion involving the three biomass constituents, i.e., hemicellulose, cellulose and lignin. The gas flow pattern in the combustion chamber and subsequent cleaning system has been modelled using a compartimental model based on two continuous perfectly mixed vessels and a plug flow vessel. Tracer tests have been conducted to determine the residence time distribution in the whole unit and the parameters of the compartimental model. Batch combustion tests have been carried out to determine the composition of the outlet Gaseous Stream and the evolution of conversion with time, whose fitting to the kinetic model allowed calculating the parameters of best fit (frequency factors and activation energies). The model suitably predicts the evolution of combustion rate in a conical spouted bed, and therefore is a useful tool for the design of industrial plants based on this technology.
Javier Bilbao - One of the best experts on this subject based on the ideXlab platform.
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kinetic modelling of pine sawdust combustion in a conical spouted bed reactor
Fuel, 2018Co-Authors: Juan F Saldarriaga, Roberto Aguado, Aitor Atxutegi, Javier Bilbao, Martin OlazarAbstract:Abstract A model has been proposed and validated for the prediction of biomass combustion rate in a conical spouted bed. The model couples the intrinsic kinetics for the process and the flow pattern of the Gaseous Stream in the unit. The kinetics is described based on a reaction scheme consisting in simultaneous devolatilization and combustion involving the three biomass constituents, i.e., hemicellulose, cellulose and lignin. The gas flow pattern in the combustion chamber and subsequent cleaning system has been modelled using a compartimental model based on two continuous perfectly mixed vessels and a plug flow vessel. Tracer tests have been conducted to determine the residence time distribution in the whole unit and the parameters of the compartimental model. Batch combustion tests have been carried out to determine the composition of the outlet Gaseous Stream and the evolution of conversion with time, whose fitting to the kinetic model allowed calculating the parameters of best fit (frequency factors and activation energies). The model suitably predicts the evolution of combustion rate in a conical spouted bed, and therefore is a useful tool for the design of industrial plants based on this technology.
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biomass to hydrogen rich gas via steam reforming of raw bio oil over ni la 2 o 3 αal 2 o 3 catalyst effect of space time and steam to carbon ratio
Fuel, 2018Co-Authors: Beatriz Valle, Javier Bilbao, Borja Aramburu, Pedro L Benito, Ana G GayuboAbstract:Abstract Hydrogen-rich gas production by steam reforming (SR) of the raw bio-oil was studied in a continuous two-step system, with the first unit of thermal treatment (at 500 °C) used for retaining the pyrolytic lignin. The remaining volatile Stream was reformed in the second unit (fluidized bed reactor) over a Ni/La2O3-αAl2O3 catalyst at 700 °C. The effect of space-time (0.04–0.38 gcatalysth/gbio-oil) and steam-to-carbon ratio (S/C) (1.5–6) on bio-oil conversion and product yields was assessed. Temperature programmed oxidation (TPO) was used to analyze the coke deposited on the Ni/La2O3-αAl2O3 catalyst. It was found that a raise in both the space-time and the S/C ratio contribute to increasing the H2 yield and to decreasing that of CO, CH4 and C2-C4 hydrocarbons. Catalyst deactivation is highly attenuated by raising space-time because of the lower deposition of encapsulating coke, which is directly related to the concentration of bio-oil oxygenates in the reaction medium. Space-time does not affect the formation of filamentous coke (less responsible for deactivation). The S/C ratio has less influence on total coke content than space time. For 700 °C, 0.38 gcatalysth/gbio-oil and S/C = 6, a hydrogen-rich Gaseous Stream (66 vol% H2) is obtained, with the H2 yield being 93% based on the bio-oil entering the catalytic reactor (or 87% based on the raw bio-oil fed into the two-step system), which decreases to 70% after 7 h time on Stream as a consequence of the low catalyst deactivation.
Enrico Bocci - One of the best experts on this subject based on the ideXlab platform.
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process simulation of a hybrid sofc mgt and enriched air steam fluidized bed gasifier power plant
International Journal of Hydrogen Energy, 2013Co-Authors: Andrea Di Carlo, Domenico Borello, Enrico BocciAbstract:Abstract The aim of this work is to experimentally and numerically analyze the performance of a integrated power plant composed by a steam oxygen fluidized bed biomass gasifier fed by woods, a Solid Oxide Fuel Cell (SOFC) and a micro Gas Turbine (mGT). The numerical analysis is carried out by using ChemCAD software. In particular, SOFC and gasifier were modeled using proper developed Fortran subroutines interfaced to the basic software. The adopted SOFC model was already validated by the authors in previous works, while the gasifier model was here developed and validated by means of experimental activities carried out by using a bench scale gasifier. Different compounds (Benzene, Toluene, Naphthalene, Phenols) were chosen to analyze the tar evolution in the Gaseous Stream during the gasification process. Hot gas cleaning (based on catalytic ceramic filter candles inserted in the freeboard of the gasifier – UNIQUE concept) was adopted to remove tar and particulates from the fuel hot gas Stream. Different moisture contents in the range between 10 and 30% (i.e. in a deviation of 10% around the usual wood moisture content of 20%) were numerically simulated as well as the degree of purity of the oxygen utilized in the power plant (between 25% and 95%, the rest being N2). The power requirement for pure oxygen production leads to a reduction of the electrical efficiency of the whole power plant. For this reason, a sensitivity analysis was conducted to find the optimal operation conditions in order to maximise the syngas (H2, CO) content in the produced gas, while maintaining a high overall electrical efficiency.
Isabella Pecorini - One of the best experts on this subject based on the ideXlab platform.
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experimental evaluation of two different types of reactors for co2 removal from Gaseous Stream by bottom ash accelerated carbonation
Waste Management, 2016Co-Authors: Lidia Lombardi, Ennio Antonio Carnevale, Isabella PecoriniAbstract:Low methane content landfill gas may be enriched by removing carbon dioxide. An innovative process, based on carbon dioxide capture and storage by means of accelerated carbonation of bottom ash is proposed and studied for the above purpose. Within this research framework we devoted a preliminary research activity to investigate the possibility of improving the way the contact between bottom ash and landfill gas takes place: this is the scope of the work reported in this paper. Two different types of reactors – fixed bed and rotating drum – were designed and constructed for this purpose. The process was investigated at laboratory scale. As the aim of this phase was the comparison of the performances of the two different reactors, we used a pure Stream of CO2 to preliminarily evaluate the reactor behaviors in the most favorable condition for the process (i.e. maximum CO2 partial pressure at ambient condition). With respect to the simple fixed bed reactor concept, some modifications were proposed, consisting of separating the ash bed in three layers. With the three layer configuration we would like to reduce the possibility for the gas to follow preferential paths through the ash bed. However, the results showed that the process performances are not significantly influenced by the multiple layer arrangement. As an alternative to the fixed bed reactor, the rotating drum concept was selected in order to provide continuous mixing of the solids. Two operating parameters were considered and varied during the tests: the filling ratio and the rotating speed. Better performances were observed for lower filling ratio while the rotating speed showed minor importance. Finally the performances of the two reactors were compared. The rotating drum reactor is able to provide improved carbon dioxide removal with respect to the fixed bed one, especially when the rotating reactor is operated at low filling ratio values and slow rotating speed values. Comparing the carbon dioxide specific removal obtained by using the rotating reactor (35–37 g/kgBA), in the best operating conditions, with that measured for the fixed bed reactor (21–23 g/kgBA), an increase of about 61–66% is observed.