Mathematical modelling of the drying of jatropha fruit: an empirical comparison

Siqueira, Valdiney Cambuy; Resende, Osvaldo; Chaves, Tarcísio Honório

doi:10.1590/s1806-66902013000200009

Cited by 24 publications

(21 citation statements)

References 25 publications

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“…Several researchers observed similar results in other agricultural products Alves et al, 2013;Siqueira et al, 2013;Resende et al, 2014;Camicia et al, 2015;Costa et al, 2015).…”

Section: Resultssupporting

confidence: 56%

“…According to Kashaninejad et al (2007), the values of the relative average error indicate the deviation of the values observed in relation to the curve estimated by the model. In addition, traditionally in studies involving the drying kinetics of agricultural products, values higher than 10% of the average relative error are adopted as unsuitable for the description of this process (Ferreira et al, 2012;Oliveira et al, 2012;Siqueira et al, 2013;Resende et al, 2014;Costa et al, 2015).…”

Section: Resultsmentioning

confidence: 99%

“…To the experimental data of humidity ratio obtained during the peanut kernels drying, eight mathematical models (Table 1) commonly used to predict the drying phenomenon of agricultural products were adjusted (Ferreira et al, 2012;Oliveira et al, 2012;Alves et al, 2013;Siqueira et al, 2013;Resende et al, 2014;Costa et al, 2015). …”

Section: Methodsmentioning

confidence: 99%

“…Different authors, in several types of agricultural products, have applied these models Morais et al, 2013;Siqueira et al, 2013;Resende et al, 2014;Costa et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

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Drying Kinetics of Peanut Kernels in Thin Layers

et al. 2017

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The aim of this study was to adjust mathematical models to the experimental data on the peanut kernels drying in thin layer, as well as to determine the effective diffusion coefficient and the main thermodynamic properties involved in drying of the grains under different air conditions. The peanut kernels, with a water content of 0.59 ± 0.002 (dry basis, d.b.), were dried in a forced air ventilation oven with different temperature levels (40, 50, 60 and 70 ºC) until reaching a water content of 0.04 ± 0.001 (d.b.). For the experimental data, eight mathematical models traditionally used to represent the drying kinetics of thin layer of agricultural products were adjusted, also being determined the effective diffusion coefficient and the thermodynamic properties, specific enthalpy and entropy and Gibbs free energy. The Diffusion Approximation, Two Terms, Midilli, Page and Thompson models represent the drying kinetics of peanut kernels in thin layers. The effective diffusivity increases with the increase of temperature, being the relation with the drying temperature described by the Arrhenius' equation. The increase in temperature promotes the decrease of the enthalpy and entropy values and the increase of the Gibbs free energy.

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“…Several researchers observed similar results in other agricultural products Alves et al, 2013;Siqueira et al, 2013;Resende et al, 2014;Camicia et al, 2015;Costa et al, 2015).…”

Section: Resultssupporting

confidence: 56%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

“…Different authors, in several types of agricultural products, have applied these models Morais et al, 2013;Siqueira et al, 2013;Resende et al, 2014;Costa et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

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Drying Kinetics of Peanut Kernels in Thin Layers

et al. 2017

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“…Na literatura, vários modelos foram propostos para analisar a secagem de produtos higroscópicos, quais sejam: teóri-cos, semiempíricos e empíricos (MARTINAZZO et al, 2007 (SIQUEIRA et al, 2013).…”

Section: Introductionunclassified

Modelagem Do Processo De Secagem De Sementes De Feijão-Caupi

et al. 2015

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RESUMO -O trabalho teve como objetivo modelar curvas de secagem do feijão-caupi (Vigna unguiculata (L.) Walp.) em diferentes temperaturas, determinar o coeficiente de difusão efetivo e a energia de ativação. Para isso, utilizou-se sementes de feijão-caupi, cultivar BRS guariba, colhidas manualmente, com teor de água de 21% (base úmida) e secas até o teor de água de 11% (base úmida). A secagem foi realizada em secador experimental sob temperaturas controladas de 30, 40 e 50 °C ± 1 °C e umidade relativa do ar de secagem entre 14 e 59%. Foram testados 12 modelos de regressão não-linear e para a seleção do melhor modelo considerou-se a significância do coeficiente de regressão pelo teste t, a magnitude do coeficiente de determinação ajustado (R²), o erro médio relativo (P) e o erro médio estimado (SE). Observou-se que o tempo de secagem para as sementes de feijão-caupi foi de 10,4, 5,6, e 2,1 h para as temperaturas de 30, 40 e 50 °C, respectivamente. Dentre a série testada, o modelo matemático de Midilli foi o que melhor se ajustou aos dados experimentais. O coeficiente de difusão aumenta com a elevação da temperatura, apresentando valores entre 5,047 x 10 -11 a 12,011 x 10 -11 m² s -1 para a faixa de temperatura de 30 a 50 °C. A relação entre o coeficiente de difusão efetivo e a temperatura de secagem podem ser descritas pela equação de Arrhenius, que apresenta uma energia de ativação de 35,04 kJ mol -1 para a difusão líquida no processo de secagem das sementes de feijão-caupi. Palavras-chave:Vigna unguiculata (L.) Walp. Curvas de secagem. Coeficiente de difusão. MODELING OF THE DRYING PROCESS THE SEEDS OF COWPEAABSTRACT -The study aimed to model the drying curves of cowpea beans (Vigna unguiculata (L.) Walp.) in different temperatures determine the coefficient of effective diffusion and the activation energy. For this, we used seeds of beans-cowpea cultivar BRS Guariba, harvested manually, with a water content of 21% (wet basis), dried until the water content 11% (wet basis). Drying was performed in the experimental dryer under controlled temperatures of 30, 40 and 50 °C ± 1 °C, and relative humidity of the air drying between 14 and 59%. 12 models of non-linear regression were tested and for selection the best model was considered to: the significance of the regression coefficient t test, the magnitude of the adjusted coefficient of determination (R²), the average relative error (P) and the estimated average error (SE). It was observed that the drying time for of the beans-cowpea seeds was 10,4 ; 5,6 ; and 2,1 h to the temperatures of 30, 40 and 50 °C, respectively; among the number tested, the mathematical model the Midilli was the best fit to experimental data. The coefficient of diffusion increases with temperature, with values between 5,047 x 10 -11 to 12,011 x 10 -11 m² s -1 for the temperature range from 30 to 50 °C. The relationship between the coefficient of diffusion effective and the drying temperature can be described by Arrhenius equation, which presents activation energy of 35,04 kJ mol -1 for spreadi...

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