Modeling moisture diffusivity, activation energy and specific energy consumption of squash seeds in a semi fluidized and fluidized bed drying

Abstract

This study investigated thin layer drying of squash seeds under semi fluidized and fluidized bed conditions with initial moisture content about 83. 99% (d.b.). An experimental fluidized bed dryer was also used in this study. Air temperature levels of 50, 60, 70 and 80°C were applied in drying samples. To estimate the drying kinetic of squash seed, seven mathematical models were used to fit the experimental data of thin layer drying. Among the applied models, Two-term model has the best performance to estimate the thin layer drying behavior of the squash seeds. Fick's second law in diffusion was used to determine the effective moisture diffusivity of squash seeds. The range of calculated values of effective moisture diffusivity for drying experiments were between 0.160×10 −9 and 0.551×10 −10 m 2 /s. Moisture diffusivity values decreased as the input air temperature decreased. Activation energy values were found to be between 31.94 and 34.49 kJ/mol for 50°C to 80°C, respectively. The specific energy consumption for squash seeds was calculated at the boundary of 0.783×10 6 and 2.303×10 6 kJ/kg. Increasing in drying air temperature in different bed conditions led to decrease in specific energy value. Results showed that applying the semi fluidized bed condition is more effective for convective drying of squash seeds. The aforesaid drying characteristics are useful to select the best operational point of fluidized bed dryer and to precise design of system.

Total phenolics, antioxidant capacity, colour and drying characteristics of date fruit dried with different methods

“…Thus, the Midilli et al and Two Term models were found to be best models to represent the thin-layer drying characteristics of the date slices. These observations are in good agreement with earlier results reported for the Midilli et al model in describing the thin-layer drying of pear (Doymaz, 2013) and mango ginger (Murthy & Manohar, 2014) and for the Two term model in drying of sultana grapes (Yaldiz et al, 2001) and squash seeds (Chayjan et al, 2013).…”

Thermal and physical properties modelling of terebinth fruit (Pistacia atlantica L.) under solar drying

“…(4) could be written as the first term of series only, without much effect on the prediction accuracy (Odjo et al 2012;Amiri Chayjan et al 2013):…”

Drying kinetics of dill leaves in a convective dryer

“…Fluidization is defined as suspending the vegetable bed (dill leaves, Anethum sowa L.) in air flow. With gradually increasing airflow through a bed of vegetable, fixed bed, minimum fluidized bed (semifluidized bed), bubbling fluidized bed and transportation will be created, respectively (Chayjan et al, 2011).Several authors had attempted to determine mathematical models for estimation of the moisture ratio and drying rate of food and biological materials during the drying process in eg potato (Bakal et al, 2011), Cuminum cyminum (Zomorodian and Moradi, 2010), carrot (Doymaz, 2004, sweet cherry (Doymaz and Ismail, 2011), and berberies (Gorjian et al, 2011). Some researchers have studied the effective moisture diffusion and energy of activation in a thin layer drying of different agricultural products such as squash seeds (Chayjan et al, 2011), onion slices (Pathare and Sharma, 2006), or milky mushroom (Arumuganathan et al, 2009).…”

“…With gradually increasing airflow through a bed of vegetable, fixed bed, minimum fluidized bed (semifluidized bed), bubbling fluidized bed and transportation will be created, respectively (Chayjan et al, 2011).…”