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Antonio Helder Parente - One of the best experts on this subject based on the ideXlab platform.
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Modelagem e simulação do efeito de parede na transmissão de calor em um forno rotativo utilizado na produção de gesso beta
2017Co-Authors: Antonio Helder ParenteAbstract:Resumo: Os fornos rotativos utilizados para obtenção de gesso beta (CaSO4 .O,5H20), a partir da calcinação do minério de gipsita (CaS04 .2H20), apresentam como principais vantagens em relação aos demais tipos a produção de um gesso mais uniforme, melhor rendimento térmico e facilidade de automação. Contudo, estes fornos tiveram origem em adaptações dos fornos de fabricação de cimento Portland, necessitando de uma melhor compreensão dos fenômenos envolvidos no processo de transferência de calor, para a elaboração de modelos de simulação mais robustos para o dimensionamento adequado em processos de produção de gesso. Como contribuição à literatura desenvolveu-se um modelo matemático, para simular o efeito de parede através de variações do perfil de temperatura no interior do revestimento refratário de um forno rotativo. A instalação de termopares em diferentes distâncias radiais numa dada seção transversal do forno permitiu medidas experimentais para ajuste do modelo matemático proposto e posterior cálculo de propriedades termofísicas do refratário e do fluxo de calor entre a parede e o leito de sólidos. Este último parâmetro foi utilizado na simulação dos perfis de temperatura das fases em escoamento através do forno. O modelo matemático proposto descreve com boa precisão as variações de temperatura a partir da superfície do refratário. Ficou evidenciada a grande contribuição do efeito de parede na recuperação de parte do fluxo de calor normal à parede. Cerca de 70 % da parcela de calor armazenado retoma para o leito de sólidos. Isto, evidencia a necessidade do uso de revestimento refratário em fornos de calcinação de gesso, acenando-se para uma maior economia de energia ao se optar por se trabalhar com fluxos de gases com temperaturas mais baixasAbstract: The Rotating Kiln used for plaster attainment beta (CaSO 4 . O,5H 20), from the calcination of the crude gypsum ore (CaSO 4 . 2H 20), present as main advantages in relation to the toa much types the production of a plaster more uniform, better thermal efficiency and easiness of automation. However, these ovens had had origin in adaptations of the Kilns of manufacture Portland cement, needing one better understanding of the involved phenomena in the process of heat transference, for the elaboration of more robust models of simulation for the sizing adjusted in processes of plaster production. As contribution to literature a mathematical model was developed, to simulate the effect of wall through variations of the profile of temperature in the inward of the refractory covering of a Rotating Kiln. The installation of thermocouples in different radial pitches in one given transversal section of the oven allowed measured experimental for smoothing of the mathematical model considered and afier calculation of thermophysical properties of refractory and the stream of heat between the wall and the solid stream bed. This last parameter was used in the simulation of the profiles of temperature of the phases in draining through the Kiln. The considered mathematical model describes with good accuracy the variations of temperature from the surface of the refractory one. It was evidenced the great contribution of the effect of wall in the backup of part of the stream of heat to the wall. About 70 % the parcel stored heat it returns for the solid stream bed. This, evidences the necessity of the fractory covering use in Kilns of plaster calcination, waving itself for a bigger economy of energy to if opting to if working with streams of gases with lower temperature
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Modelagem e simulação do efeito de parede na transmissão de calor em um forno rotativo utilizado na produção de gesso beta
Universidade Estadual de Campinas . Faculdade de Engenharia Quimica, 2001Co-Authors: Antonio Helder ParenteAbstract:Os fornos rotativos utilizados para obtenção de gesso beta (CaSO4 .O,5H20), a partir da calcinação do minério de gipsita (CaS04 .2H20), apresentam como principais vantagens em relação aos demais tipos a produção de um gesso mais uniforme, melhor rendimento térmico e facilidade de automação. Contudo, estes fornos tiveram origem em adaptações dos fornos de fabricação de cimento Portland, necessitando de uma melhor compreensão dos fenômenos envolvidos no processo de transferência de calor, para a elaboração de modelos de simulação mais robustos para o dimensionamento adequado em processos de produção de gesso. Como contribuição à literatura desenvolveu-se um modelo matemático, para simular o efeito de parede através de variações do perfil de temperatura no interior do revestimento refratário de um forno rotativo. A instalação de termopares em diferentes distâncias radiais numa dada seção transversal do forno permitiu medidas experimentais para ajuste do modelo matemático proposto e posterior cálculo de propriedades termofísicas do refratário e do fluxo de calor entre a parede e o leito de sólidos. Este último parâmetro foi utilizado na simulação dos perfis de temperatura das fases em escoamento através do forno. O modelo matemático proposto descreve com boa precisão as variações de temperatura a partir da superfície do refratário. Ficou evidenciada a grande contribuição do efeito de parede na recuperação de parte do fluxo de calor normal à parede. Cerca de 70 % da parcela de calor armazenado retoma para o leito de sólidos. Isto, evidencia a necessidade do uso de revestimento refratário em fornos de calcinação de gesso, acenando-se para uma maior economia de energia ao se optar por se trabalhar com fluxos de gases com temperaturas mais baixasThe Rotating Kiln used for plaster attainment beta (CaSO 4 . O,5H 20), from the calcination of the crude gypsum ore (CaSO 4 . 2H 20), present as main advantages in relation to the toa much types the production of a plaster more uniform, better thermal efficiency and easiness of automation. However, these ovens had had origin in adaptations of the Kilns of manufacture Portland cement, needing one better understanding of the involved phenomena in the process of heat transference, for the elaboration of more robust models of simulation for the sizing adjusted in processes of plaster production. As contribution to literature a mathematical model was developed, to simulate the effect of wall through variations of the profile of temperature in the inward of the refractory covering of a Rotating Kiln. The installation of thermocouples in different radial pitches in one given transversal section of the oven allowed measured experimental for smoothing of the mathematical model considered and afier calculation of thermophysical properties of refractory and the stream of heat between the wall and the solid stream bed. This last parameter was used in the simulation of the profiles of temperature of the phases in draining through the Kiln. The considered mathematical model describes with good accuracy the variations of temperature from the surface of the refractory one. It was evidenced the great contribution of the effect of wall in the backup of part of the stream of heat to the wall. About 70 % the parcel stored heat it returns for the solid stream bed. This, evidences the necessity of the fractory covering use in Kilns of plaster calcination, waving itself for a bigger economy of energy to if opting to if working with streams of gases with lower temperature
Parente, Antonio Helder - One of the best experts on this subject based on the ideXlab platform.
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Modelagem e simulação do efeito de parede na transmissão de calor em um forno rotativo utilizado na produção de gesso beta
[s.n.], 2018Co-Authors: Parente, Antonio HelderAbstract:Orientador: Elias Basile TambourgiTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia QuimicaResumo: Os fornos rotativos utilizados para obtenção de gesso beta (CaSO4 .O,5H20), a partir da calcinação do minério de gipsita (CaS04 .2H20), apresentam como principais vantagens em relação aos demais tipos a produção de um gesso mais uniforme, melhor rendimento térmico e facilidade de automação. Contudo, estes fornos tiveram origem em adaptações dos fornos de fabricação de cimento Portland, necessitando de uma melhor compreensão dos fenômenos envolvidos no processo de transferência de calor, para a elaboração de modelos de simulação mais robustos para o dimensionamento adequado em processos de produção de gesso. Como contribuição à literatura desenvolveu-se um modelo matemático, para simular o efeito de parede através de variações do perfil de temperatura no interior do revestimento refratário de um forno rotativo. A instalação de termopares em diferentes distâncias radiais numa dada seção transversal do forno permitiu medidas experimentais para ajuste do modelo matemático proposto e posterior cálculo de propriedades termofísicas do refratário e do fluxo de calor entre a parede e o leito de sólidos. Este último parâmetro foi utilizado na simulação dos perfis de temperatura das fases em escoamento através do forno. O modelo matemático proposto descreve com boa precisão as variações de temperatura a partir da superfície do refratário. Ficou evidenciada a grande contribuição do efeito de parede na recuperação de parte do fluxo de calor normal à parede. Cerca de 70 % da parcela de calor armazenado retoma para o leito de sólidos. Isto, evidencia a necessidade do uso de revestimento refratário em fornos de calcinação de gesso, acenando-se para uma maior economia de energia ao se optar por se trabalhar com fluxos de gases com temperaturas mais baixasAbstract: The Rotating Kiln used for plaster attainment beta (CaSO 4 . O,5H 20), from the calcination of the crude gypsum ore (CaSO 4 . 2H 20), present as main advantages in relation to the toa much types the production of a plaster more uniform, better thermal efficiency and easiness of automation. However, these ovens had had origin in adaptations of the Kilns of manufacture Portland cement, needing one better understanding of the involved phenomena in the process of heat transference, for the elaboration of more robust models of simulation for the sizing adjusted in processes of plaster production. As contribution to literature a mathematical model was developed, to simulate the effect of wall through variations of the profile of temperature in the inward of the refractory covering of a Rotating Kiln. The installation of thermocouples in different radial pitches in one given transversal section of the oven allowed measured experimental for smoothing of the mathematical model considered and afier calculation of thermophysical properties of refractory and the stream of heat between the wall and the solid stream bed. This last parameter was used in the simulation of the profiles of temperature of the phases in draining through the Kiln. The considered mathematical model describes with good accuracy the variations of temperature from the surface of the refractory one. It was evidenced the great contribution of the effect of wall in the backup of part of the stream of heat to the wall. About 70 % the parcel stored heat it returns for the solid stream bed. This, evidences the necessity of the fractory covering use in Kilns of plaster calcination, waving itself for a bigger economy of energy to if opting to if working with streams of gases with lower temperaturesDoutoradoSistemas de Processos Quimicos e InformaticaDoutor em Engenharia Químic
Dennis R Van Puyvelde - One of the best experts on this subject based on the ideXlab platform.
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comparison of discrete elemental modelling to experimental data regarding mixing of solids in the transverse direction of a Rotating Kiln
Chemical Engineering Science, 2006Co-Authors: Dennis R Van PuyveldeAbstract:Abstract Finnie et al. [Finnie, G.J., Kruyt, N.P., Ye M., Zeilstra, C., Kuipers, J.A.M., 2005. Longitudinal and transverse mixing in rotary Kilns: a discrete element method approach. Chemical Engineering Science 60, 4083–4091] developed a discrete elemental model to simulate the mixing of solids in a rotary Kiln. It is interesting to analyse and compare their results to those obtained through experimental observations such as those by Henein et al. [Henein, H., Brimacombe, J.K., Watkinson, A.P., 1983. Experimental study of transverse bed motion in rotary Kilns. Metallurgical Transactions B 14B, 191–205] Van Puyvelde et al. [Van Puyvelde, D.R., Young, B.R., Wilson, M.A., Schmitd, S.J., 1999. Experimental determination of transverse mixing kinetics in a rolling drum by image analysis. Powder Technology 106, 183–191; 2000. Modelling transverse mixing in a rolling drum. Canadian Journal of Chemical Engineering 78, 635–642] and Mellmann [Mellmam, J., 2001. The transverse motion of solids in Rotating cylinders—forms of motion and transition behavior. Powder Technology 118, 251–270].
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simulating the mixing and segregation of solids in the transverse section of a Rotating Kiln
Powder Technology, 2006Co-Authors: Dennis R Van PuyveldeAbstract:Abstract Rotating Kilns are widely used in industry to process granular material. These processes include calcination of mineral ores, drying of foods and grains, combustion of wastes and manufacturing of pharmaceuticals. Since models developed for a particular process are often unique to that process there is a need to develop more generic models to predict the mixing and segregation in the transverse section of a rotary Kiln. This paper presents a mathematical simulation – based on experimental observations – to estimate the mixing rate, final extent of mixing and the final distribution of material due to segregation. The models used in the simulation allow for scale-up of processes to produce a simulation that is applicable to a broad range of industrial processes. Independent experiments were used to verify the simulation and it was found that the mixing rate, the final extent of mixedness and the final segregated state could be predicted to within acceptable errors.
Alessio Langella - One of the best experts on this subject based on the ideXlab platform.
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campanian ignimbrite as raw material for lightweight aggregates
Applied Clay Science, 2007Co-Authors: R De Gennaro, Piergiulio Cappelletti, Guido Cerri, M De Gennaro, M Dondi, Sossio Fabio Graziano, Alessio LangellaAbstract:Abstract Aim of this research is an evaluation of the zeolitized facies of Campanian Ignimbrite as raw material for the production of lightweight expanded aggregates (LEA). A commercial product (Cab70) was used as reference for this rock. Tests were carried out on “pure” samples or mixed with an industrial waste mud (DPM — Dried Polishing Mud) deriving from a porcelain stoneware tile polishing process. This mud contains SiC, a phase known to act as bloating enhancer. Raw materials were subjected to mineralogical (XRPD–RIR method) and chemical (XRF) analyses. Bloating upon heating was measured (Leitz heating microscope) on Cab70, DPM and on three mixtures having the following Cab70/DPM ratios: 85/15 (Mix1); 70/30 (Mix2); 50/50 (Mix3). LEA production was assessed both in static (muffle Kiln) and in dynamic (Rotating Kiln) conditions by firing pellets, 3–8 mm in size, between 1220–1380 °C. The unit weight of the single particle was determined on fired and unfired products. All materials evidenced a decreasing density with temperature whereas the same parameter decreases with DPM increasing content. Cab70 LEAs never dropped below 0.90 g/cm3, even at the highest temperature, whereas DPM LEAs range between 0.86 g/cm3 (at 1260 °C) and 0.46 g/cm3 (at 1380 °C). A direct but not linear relationship between DPM content and density was evidenced. Among the three mixtures, Mix2 showed the lowest DPM content able to produce the strongest density reduction. To get LEAs with the same density the Rotating Kiln required temperatures generally 60–80 °C higher than those of the muffle Kiln. This difference should be related to the different thermal insulation of the two systems during firing. Two sets of LEAs were massively produced in dynamic conditions from Cab70 (at 1380 °C) and Mix2 (at 1300 °C). These latter showed better technical performances in terms of unit weight of the single particle (0.81 vs. 0.98 g/cm3), bulk unit weight (460 vs. 565 kg/m3), water absorption coefficients (1.4 vs. 5.5% after 24 h) and compressive strength of the particles (2.9 vs. 0.6 MPa). Differences in pore shape, dimension, abundance and spatial distribution were observed by SEM between the two sets. The technical features of these LEAs were comparable to some expanded clays, with similar grain size, commercialised in Italy. These results are worth interesting as they reveal new perspectives of application both for a rock characterized by a low exploitation cost and widely available in central-southern Italy, as well as for an industrial waste produced in high amount but not recycled at all.
R De Gennaro - One of the best experts on this subject based on the ideXlab platform.
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campanian ignimbrite as raw material for lightweight aggregates
Applied Clay Science, 2007Co-Authors: R De Gennaro, Piergiulio Cappelletti, Guido Cerri, M De Gennaro, M Dondi, Sossio Fabio Graziano, Alessio LangellaAbstract:Abstract Aim of this research is an evaluation of the zeolitized facies of Campanian Ignimbrite as raw material for the production of lightweight expanded aggregates (LEA). A commercial product (Cab70) was used as reference for this rock. Tests were carried out on “pure” samples or mixed with an industrial waste mud (DPM — Dried Polishing Mud) deriving from a porcelain stoneware tile polishing process. This mud contains SiC, a phase known to act as bloating enhancer. Raw materials were subjected to mineralogical (XRPD–RIR method) and chemical (XRF) analyses. Bloating upon heating was measured (Leitz heating microscope) on Cab70, DPM and on three mixtures having the following Cab70/DPM ratios: 85/15 (Mix1); 70/30 (Mix2); 50/50 (Mix3). LEA production was assessed both in static (muffle Kiln) and in dynamic (Rotating Kiln) conditions by firing pellets, 3–8 mm in size, between 1220–1380 °C. The unit weight of the single particle was determined on fired and unfired products. All materials evidenced a decreasing density with temperature whereas the same parameter decreases with DPM increasing content. Cab70 LEAs never dropped below 0.90 g/cm3, even at the highest temperature, whereas DPM LEAs range between 0.86 g/cm3 (at 1260 °C) and 0.46 g/cm3 (at 1380 °C). A direct but not linear relationship between DPM content and density was evidenced. Among the three mixtures, Mix2 showed the lowest DPM content able to produce the strongest density reduction. To get LEAs with the same density the Rotating Kiln required temperatures generally 60–80 °C higher than those of the muffle Kiln. This difference should be related to the different thermal insulation of the two systems during firing. Two sets of LEAs were massively produced in dynamic conditions from Cab70 (at 1380 °C) and Mix2 (at 1300 °C). These latter showed better technical performances in terms of unit weight of the single particle (0.81 vs. 0.98 g/cm3), bulk unit weight (460 vs. 565 kg/m3), water absorption coefficients (1.4 vs. 5.5% after 24 h) and compressive strength of the particles (2.9 vs. 0.6 MPa). Differences in pore shape, dimension, abundance and spatial distribution were observed by SEM between the two sets. The technical features of these LEAs were comparable to some expanded clays, with similar grain size, commercialised in Italy. These results are worth interesting as they reveal new perspectives of application both for a rock characterized by a low exploitation cost and widely available in central-southern Italy, as well as for an industrial waste produced in high amount but not recycled at all.
