Identification and analysis of mass transfer coefficients and effective diffusion coefficients for models of solvent extraction of Montan wax

2016 ◽  
Vol 51 (13) ◽  
pp. 2183-2197 ◽  
Author(s):  
Yan Wang ◽  
Volker Herdegen ◽  
Jens-Uwe Repke
Keyword(s):  
Mass Transfer ◽  
Solvent Extraction ◽  
Diffusion Coefficients ◽  
Effective Diffusion ◽  
Transfer Coefficients ◽  
Mass Transfer Coefficients ◽  
Effective Diffusion Coefficients

scholarly journals Heat and mass transfer coefficients and modeling of infrared drying of banana slices

Revista CERES ◽  
2017 ◽  
Vol 64 (5) ◽  
pp. 457-464 ◽  
Author(s):  
Fernanda Machado Baptestini ◽  
Paulo Cesar Corrêa ◽  
Gabriel Henrique Horta de Oliveira ◽  
Fernando Mendes Botelho ◽  
Ana Paula Lelis Rodrigues de Oliveira
Keyword(s):  
Mass Transfer ◽  
Diffusion Coefficient ◽  
Shelf Life ◽  
Heat And Mass Transfer ◽  
Effective Diffusion Coefficient ◽  
Effective Diffusion ◽  
Transfer Coefficients ◽  
Mass Transfer Coefficients ◽  
Infrared Drying ◽  
Ripening Stages

ABSTRACT Banana is one of the most consumed fruits in the world, having a large part of its production performed in tropical countries. This product possesses a wide range of vitamins and minerals, being an important component of the alimentation worldwide. However, the shelf life of bananas is short, thus requiring procedures to prevent the quality loss and increase the shelf life. One of these procedures widely used is drying. This work aimed to study the infrared drying process of banana slices (cv. Prata) and determine the heat and mass transfer coefficients of this process. In addition, effective diffusion coefficient and relationship between ripening stages of banana and drying were obtained. Banana slices at four different ripening stages were dried using a dryer with infrared heating source with four different temperatures (65, 75, 85, and 95 ºC). Midilli model was the one that best represented infrared drying of banana slices. Heat and mass transfer coefficients varied, respectively, between 46.84 and 70.54 W m-2 K-1 and 0.040 to 0.0632 m s-1 for temperature range, at the different ripening stages. Effective diffusion coefficient ranged from 1.96 to 3.59 × 10-15 m² s-1. Activation energy encountered were 16.392, 29.531, 23.194, and 25.206 kJ mol-1 for 2nd, 3rd, 5th, and 7th ripening stages, respectively. Ripening stages did not affect the infrared drying of bananas.

Calculation of the Effective Diffusion Coefficients in Drying of Chemical and Mechanical Pretreated Rosehip Fruits (Rosa eglanteria L.) with Selected Mass Transfer Models

2013 ◽  
Vol 9 (4) ◽  
pp. 481-486 ◽  
Author(s):  
Alejandra Mabellini ◽  
Elizabeth Ohaco ◽  
Carlos Márquez ◽  
Jorge E. Lozano ◽  
Antonio De Michelis
Keyword(s):  
Mass Transfer ◽  
Effective Mass ◽  
Diffusion Coefficients ◽  
Effective Diffusion ◽  
Ethyl Oleate ◽  
Mass Diffusion ◽  
Water Diffusion ◽  
Second Law ◽  
Effective Diffusion Coefficients ◽  
Transfer Models

AbstractThe aim of this work was to select models of mass transfer to estimate effective mass diffusion coefficients during the dehydration of Rosa eglanteria fruits with air at 70°C. Fruits were pretreated chemically and mechanically (dipping it in NaOH and ethyl oleate solutions and cutting or perforating the fruit cuticle). Selected models were those of Becker and Fick’s second law, considering fruit shrinkage during drying. Both models satisfactorily predict the fruit drying, and the different pretreatments, to total or partially remove this waxen cuticle, noticeably improved water diffusion, reducing the time of processing from 28% (NaOH) to 52% (oleate and mechanical pretreatments). Mechanical pretreatments were the more effective, because oleate presents quality problems.

Non‐dispersive Solvent Extraction of Alkali Metals with the Dicyclohexano 18 Crown 6: Evaluation of Mass Transfer Coefficients

2004 ◽  
Vol 39 (16) ◽  
pp. 3839-3858 ◽  
Author(s):  
Jaouad Haddaoui ◽  
Dominique Trébouet ◽  
José Miguel Loureiro ◽  
Michel Burgard
Keyword(s):  
Mass Transfer ◽  
Solvent Extraction ◽  
Alkali Metals ◽  
Transfer Coefficients ◽  
Mass Transfer Coefficients

scholarly journals Dehydration of infrared ginger slices: heat and mass transfer coefficient and modeling

2019 ◽  
Vol 43 ◽  
Author(s):  
Paulo Cesar Corrêa ◽  
Fernanda Machado Baptestini ◽  
Juliana Soares Zeymer ◽  
Marcos Eduardo Viana de Araujo ◽  
Rita Cristina Pereira de Freitas ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Diffusion Coefficient ◽  
Heat And Mass Transfer ◽  
Effective Diffusion Coefficient ◽  
Diffusion Theory ◽  
Effective Diffusion ◽  
Heat Transfer Process ◽  
Transfer Coefficients ◽  
Mass Transfer Coefficients ◽  
And Storage

ABSTRACT Dehydration of plant products extends its shelf life and reduces its mass and volume, which increases transport and storage efficiency and adds value to food. However, it is an intensive process in energy and time, making necessary the search for more efficient technologies, Thus, this study aimed to investigate the infrared ginger dehydration process by approaching the constant period of dehydration to the theory of mass and heat transfer process to the wet bulb thermometer and the decreasing period of dehydration to liquid diffusion theory. We submitted 5.0 mm thickness and 2.0 cm diameter slices to a dryer with infrared radiation at 50, 60, 70, 80, 90 and 100 °C until constant mass. Heat and mass transfer coefficients, and effective diffusion coefficient increased linearly with temperature increasing, resulting in values ranging from 69.40 to 92.23 W m-2 °C-1, 0.062 to 0.089 m s-1 and 3.81 x 10-9 to 1.13 x 10-8 m2 s-1. Variation of heat and mass transfer coefficients was described by a linear model and the variation of effective diffusion coefficient with the temperature was described with the Arrhenius relation, whose activation energy was 22.07 kJ mol-1. The modified Henderson and Pabis model was able to satisfactorily describe the period of decreasing drying rate.

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