Thin-layer modelling of black tea drying process

Panchariya, P. C.; Popović, D.; Sharma, Ajay K.

doi:10.1016/s0260-8774(01)00126-1

Cited by 300 publications

(210 citation statements)

References 28 publications

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“…Resultados semelhantes foram obtidos por Simal et al (2005) para a secagem de kiwi em cubos a temperatura variando de 30 a 90 °C, ao ajustarem os dados experimentais aos modelos. Panchariya et al (2002) observaram que o modelo exponencial foi o que melhor descreveu a cinética de secagem de chá preto (temperatura de 80-120 °C e velocidade do ar de 0,25-0,65 m s -1 ). Barbosa et al (2007) Avaliando a distância euclidiana, assim como a análise de variância dos resultados, observa-se diferença significativa entre os resultados dos modelos sendo aconselhável avaliar as diferenças pelos resultados apresentados na Tabela 6.…”

Section: Methodsunclassified

Modelagem matemática do processo de secagem da massa fibrosa de mandioca

Castiglioni

Silva

Caliari

et al. 2013

Rev. bras. eng. agríc. ambient.

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RESUMOO presente trabalho teve por objetivo elaborar um modelo matemático para o processo de secagem da massa fibrosa de mandioca e compará-lo com modelos da literatura. O método dos mínimos quadrados foi usado para ajustar os valores experimentais a um modelo semi-empírico. Os resultados experimentais e preditos foram avaliados estatisticamente por análise de variância, para verificar diferenças significativas. As variáveis estudadas foram temperatura e fluxo de ar em secador de bandeja. O modelo construído e o de Page apresentaram valores de erro relativo médio inferiores a 6%, podendo ser utilizados para a predição da cinética de secagem nas condições. Palavras-chave:Manihot esculenta Crantz, resíduo, subproduto, cinética de secagem, modelo matemático Mathematical modeling of drying process of fibrous mass of cassava ABSTRACT The purpose of this study was to develop a mathematical model to describe the drying process of cassava fibrous mass and compare it with other models from the literature. The Least-Squares Method is used to adjust the experimental values to a semi-empirical model. The experimental and predicted results were statisticaly compared using variance analysis to identify significant differences. The studied variables were temperature and air flow in tray dryer. The constructed model and Page model had values of mean relative error less than 6%, and may be used to predict the drying kinetics.

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Section: Methodsunclassified

Modelagem matemática do processo de secagem da massa fibrosa de mandioca

Castiglioni

Silva

Caliari

et al. 2013

Rev. bras. eng. agríc. ambient.

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“…Onider et al (2010) studied the drying kinetics of rough rice at varying temperatures (19-26°C) and relative humidity's (19-68%) and observed the fastest drying rate at the highest temperature (26°C). Panchariya et al (2002) studied thin layer drying of black tea at various temperatures (80-120°C) and air velocities and reported the fastest drying rate at the highest temperature (120°C). Gely and Santalla (2007) studied the effects of initial moisture content and temperature (50-90°C) on the drying rate of quinoa seeds and observed the highest drying rates at 90°C.…”

Section: Ajabsmentioning

confidence: 99%

Drying of Poultry Manure for Use as Animal Feed

Ghaly¹,

MacDonald²

2012

American Journal of Agricultural and Biological Sciences

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The poultry industry is one of the largest and fastest growing sectors of livestock production in the world. The estimated 2010 world flock was over 18 billion birds with a yearly manure output of 22 million tonnes. Storage and disposal of raw poultry manure have become an environmental problem because of the associated air, water and soil pollution. Environmental and health problems such as odor and pathogens that may arise during and after land application of raw manure can be eliminated by drying. Dried manure can be utilized as a feed for ruminants because of its high nitrogen content. The aim of this study was to investigate the effects of drying temperature and depth, as well as the nutritional profile of dried manure and its suitability as an animal feed. Dried poultry manure contained sufficient levels of digestible energy, crude fiber, crude protein, crude fat, cobalt and iodine. Although dried poultry manure did not meet the dietary requirements for calcium, chloride, magnesium, phosphorus, potassium, sodium, copper, iron, manganese, selenium, sulfur or zinc it could be used as a feed stuff for ruminants after supplementation with the required nutrients. Heated air drying was most efficient at 60°C and at a depth of 3 cm. During drying poultry manure decreased in pH (8.4-6.9), protein content (43 to 39-43%) and amino acid content. The greatest reductions in microbial population occurred at the highest temperature (60°C) and the lowest manure depth (1cm). Reductions in the number of bacteria, mold/yeast and E. coli were 65-99, 74-99 and 99.97% respectively, Salmonellae was not detected in the dried product. Dried poultry manure was found to have a non-offensive odor. Odor intensity and offensiveness were reduced by 65 and 69% respectively during drying. Thin layer heated air drying of poultry manure between 40 and 60°C created a safe and nutritionally appropriate feed for ruminants.

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“…Em estudos sobre a secagem de produtos agrícolas em camada delgada são usados três tipos de modelo sendo eles: o modelo teórico, que considera apenas a resistência interna à transferência de calor e água entre o produto e o ar quente, os modelos semiteóricos e os empíricos, que ponderam somente a resistência externa a temperatura e umidade relativa do ar de secagem (Midilli et al, 2002;Panchariya et al, 2002).…”

Section: Introductionunclassified

Cinética de secagem de folhas de timbó (Serjania marginata Casar)

Martins

Lage

Goneli

et al. 2015

Rev. bras. eng. agríc. ambient.

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R E S U M OPropôs-se, neste trabalho, avaliar a cinética de secagem de folhas de timbó (Serjania marginata Casar) e ajustar diferentes modelos matemáticos aos valores experimentais de razão de umidade. As folhas de timbó foram colhidas com teor de água inicial de 2,03 ± 0,10 decimal b.s., sendo submetidas à secagem sob condições controladas de temperatura (40, 50, 60 e 70 °C), até o teor de água de 0,08 ± 0,02 decimal b.s. Aos dados experimentais foram ajustados dez modelos matemáticos utilizados para representação da secagem de produtos agrícolas. Com base nos resultados obtidos o modelo matemático de Midilli é o que melhor representa a cinética de secagem para as folhas de timbó. O aumento da temperatura promove: uma taxa maior de remoção de água nas folhas de timbó durante a secagem; aumento do coeficiente de difusão efetivo sendo que esta relação pode ser descrita pela equação de Arrhenius que apresenta uma energia de ativação para a difusão líquida durante a secagem de 81,39 kJ mol -1 para as folhas de timbó; aumento da energia livre de Gibbs, enquanto a entalpia e a entropia decrescem. Drying kinetics of Serjania marginata Casar leaves A B S T R A C TThis study aimed to evaluate the kinetics of drying of Serjania marginata leaves, as well as to adjust different mathematical models to the experimental values of the moisture ratio. The Serjania marginata Casar leaves were harvested with initial moisture content of 2.03 ± 0,10 decimal dry basis., and submitted to drying process under controlled conditions of temperature (40, 50, 60 and 70 ºC), until the moisture content of 0.08 ± 0,02. Ten mathematical models were fitted to the experimental data and utilized to predict the drying process of agricultural products. Based on the obtained results, the mathematical model of Midilli best represented the kinetics of drying leaves of Serjania marginata. The increase in temperature promotes: an increased rate of water removal in Serjania marginata leaves during drying; the increase of the effective diffusion coefficient, and this relationship can be described through the Arrhenius equation, which presents an activation energy for the liquid diffusion during drying of 81.39 kJ mol -1 for Serjania marginata leaves; an increase in Gibbs free energy, while the enthalpy and entropy decrease.Palavras-chave: modelo de Midilli coeficiente de difusão propriedades termodinâmicas razão de umidade

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Thin-layer modelling of black tea drying process

Cited by 300 publications

References 28 publications

Modelagem matemática do processo de secagem da massa fibrosa de mandioca

Modelagem matemática do processo de secagem da massa fibrosa de mandioca

Drying of Poultry Manure for Use as Animal Feed

Cinética de secagem de folhas de timbó (Serjania marginata Casar)

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