BALKABAĞININ AKIŞKAN YATAKLI KURUTUCUDA KURUTULMASININ DENEYSEL VE TEORİK İNCELENMESİ

Yıl 2016, Cilt: 21 Sayı: 2, 145 - 158, 13.10.2016

Mert Gur

https://doi.org/10.17482/uujfe.84114

Öz

Bu çalışmada balkabağının akışkan yataklı kurutucuda kurutma karakteristiği incelenmiştir. Deneyler için balkabağı tarla hasadından sonra küp şeklinde kesilerek,  50, 60 ve 70 °C’deki üç farklı sıcaklıktaki hava ile akışkan yataklı kurutucuda kurutulmuştur. Kurutulan balkabağının başlangıç nemi ıslak bazda %95 (kuru bazda  %1930) mertebelerinde olup akışkanlaşma hızı 3,5 m/s seçilmiştir. Deney sonuçlarından, akışkan yataklı kurutucuda oldukça yüksek kuruma hızlarına ulaşıldığı ve böylece kuruma sürelerinin klasik yöntemlere ve sabit yataklı kurutuculara göre çok kısa sürelere indiği görülmüştür. Kurutma deneylerimizde en fazla 120 dakika sonunda %6’dan düşük bal kabağı nemlerine ulaşmak mümkün olmuştur. Bal kabağı kurutmanın matematiksel modellenmesi için literatürde sıkça kullanılan yarı-teorik modellerden Lewis modeli, Henderson ve Pabis modeli, Page modeli ve logaritmik ince tabaka kurutma modelleri seçilmiştir. Bunun yanında Fick’in birinci yasası olan kurutma teorik modeli ile de kurutma karakteristiği incelenmiştir. Bu modelde hesaplanan etkin difüzyon katsayılarının sonuçları, literatürdeki değerleri ile karşılaştırılmıştır. Akışkan yataklı kurutucuda hesaplanan etkin difüzyon katsayıları, sabit yataklı kurutuculara göre %70’lere varan daha yüksek değerlere ulaşmıştır. Bunun yanında etkin difüzyon katsayılarının sıcaklığa bağımlılıkları Arrhenius denklemi ile açıklanmıştır.

Anahtar Kelimeler

Balkabağı, Kurutma; Akışkan Yataklı Kurutucu; Kurutma Karakteristiği

Experimental and Theoretical Investigation of Pumpkin Drying in Fluidized Bed Dryer

Öz

Thin layer drying characteristics of pumpkin cube were experimentally investigated in a  fluidized bed dryer. Experiments were performed at three different drying temperatures: 50, 60 and 70 °C.  Pumpkin used in the experiments had an initial moisture content of  95% wet basis (1930 % dry basis). The drying air velocities were set to 3.5 m/s to achieve fluidization. Experimental results show that large drying rates are obtained in the fluidized bed dryer, which are much higher than those obtained with conventional methods and convective tray dryer. In just 120 minutes moisture contents lower than 6% wet basis were achieved. Pumkin drying was mathematically modeled using the Lewis, Henderson ve Pabis, Page, and logaritmic models,  all of which are semi-emperical models widely applied in the literature. Using Fick’s first law effective diffusivities were calculated and compared with those in the literature. Effective diffusion coefficients obtained in the fluidized bed dryer were up to 70% higher than the diffusion coefficients obtained in convective tray dryers. Temperature dependence of effective diffusion coefficients was described by an Arrhenius-type relationship.

Anahtar Kelimeler

Pumpkin, Drying; Fluidized Bed Dryer; Drying Characteristics

Kaynakça

• Aghbashlo, M. ve diğerleri (2008) Influence of drying conditions on the effective moisture diffusivity, energy of activation and energy consumption during the thin-layer drying of berberis fruit (Berberidaceae), Energy Conversion and Management, 49, 2865-71, doi:10.1016/j.enconman.2008.03.009
• Akpinar, E. ve diğerleri (2003) Experimental investigation of drying behaviour and conditions of pumpkin slices via a cyclone‐type dryer, Journal of the Science of Food and Agriculture, 83, 1480-86, doi: 10.1002/jsfa.1565
• Alibas, I. (2007) Microwave, air and combined microwave–air-drying parameters of pumpkin slices, LWT-Food Science and Technology, 40, 1445-51, doi:10.1016/j.lwt.2006.09.002
• Arévalo-Pinedo, A. ve Murr, F. E. (2006) Kinetics of vacuum drying of pumpkin (Cucurbita maxima): Modeling with shrinkage, Journal of Food Engineering, 76, 562-67, doi:10.1016/j.jfoodeng.2005.06.003
• Crank, J. 1979. The mathematics of diffusion (Oxford university press).
• Diamante, L. M. ve Munro, P. A. (1993) Mathematical modelling of the thin layer solar drying of sweet potato slices, Solar energy, 51, 271-76, doi:10.1016/0038-092X(93)90122-5
• Doymaz, I. (2004) Convective air drying characteristics of thin layer carrots, Journal of food engineering, 61, 359-64, doi:10.1016/S0260-8774(03)00142-0
• Doymaz, I. (2007) The kinetics of forced convective air-drying of pumpkin slices, Journal of food engineering, 79, 243-48, doi:10.1016/j.jfoodeng.2006.01.049
• Erbay, Z. ve Icier, F. (2010) A review of thin layer drying of foods: theory, modeling, and experimental results, Critical reviews in food science and nutrition, 50, 441-64, doi:10.1080/10408390802437063
• Gur, M. ve Gur, M. 2014. 'Comparing Corn Drying in Fluidized Bed Dryer and Convective Tray Dryer.' in, Progress in Exergy, Energy, and the Environment (Springer), doi: 10.1007/978-3-319-04681-5_65
• Henderson, S. (1974) Progress in developing the thin layer drying equation, Transactions of the ASAE, 17, 1167-68, doi: 10.13031/2013.37052
• Henderson, S. ve Pabis, S. (1961) Grain drying theory I. Temperature effect on drying coefficient, Journal of Agricultural Engineering Research, 6, 169-74.
• Keey, R. B. 2013. Drying: principles and practice (Elsevier).
• Lewis, W. K. (1921) The Rate of Drying of Solid Materials, Industrial & Engineering Chemistry, 13, 427-32, doi: 10.1021/ie50137a021
• Madamba, P. S. ve diğerleri (1996) The thin-layer drying characteristics of garlic slices, Journal of food engineering, 29, 75-97, doi:10.1016/0260-8774(95)00062-3
• Madhiyanon, T. ve diğerleri (2009) Models of fluidized bed drying for thin-layer chopped coconut, Applied Thermal Engineering, 29, 2849-54, doi:10.1016/j.applthermaleng.2009.02.003
• Mazza, G. ve LeMaguer, M. (1980) Dehydration of onion: some theoretical and practical considerations, International Journal of Food Science & Technology, 15, 181-94, doi: 10.1111/j.1365-2621.1980.tb00930.x
• Öztekin, S. ve diğerleri (1999) Crop drying programme in Turkey, Renewable energy, 16, 789-94, doi:10.1016/S0960-1481(98)00282-1
• Pala, M. ve diğerleri (1996) Effects of pretreatments on the quality of open-air and solar dried apricots, Nahrung-Food, 40, 137-41, doi: 10.1002/food.19960400308
• Ramesh, M. ve diğerleri (2001) Influence of processing parameters on the drying of spice paprika, Journal of Food Engineering, 49, 63-72, doi:10.1016/S0260-8774(00)00185-0
• Ratnayake, R. ve diğerleri (2004) Influence of cultivar, storage and cooking on the mechanical properties of winter squash (Cucurbita maxima), Journal of the Science of Food and Agriculture, 84, 433-40, doi: 10.1002/jsfa.1674
• Sahin, A. ve Dincer, I. (2005) Prediction of drying times for irregular shaped multi-dimensional moist solids, Journal of food engineering, 71, 119-26, doi:10.1016/j.jfoodeng.2004.10.024
• Seremet, L. ve diğerleri (2016) Effect of different drying methods on moisture ratio and rehydration of pumpkin slices, Food chemistry, 195, 104-09, doi:10.1016/j.foodchem.2015.03.125
• Tatemoto, Y. ve diğerleri (2001) Effect of fluidizing particle on drying characteristics of porous material in fluidized bed, Drying Technology, 19, 1305-18, doi:10.1081/DRT-100105290
• Tunde-Akintunde, T. ve Ogunlakin, G. (2013) Mathematical modeling of drying of pretreated and untreated pumpkin, Journal of food science and technology, 50, 705-13, doi: 10.1007/s13197-011-0392-2
• Tunde-Akintunde, T. Y. ve Ogunlakin, G. O. (2011) Influence of drying conditions on the effective moisture diffusivity and energy requirements during the drying of pretreated and untreated pumpkin, Energy Conversion and Management, 52, 1107-13.
• Wang, Z. H. ve Chen, G. (2000) Heat and mass transfer in batch fluidized-bed drying of porous particles, Chemical Engineering Science, 55, 1857-69.
• Yağcıoğlu, A. ve diğerleri. 1999. "Drying Characteristics of Laurel Leaves Under Different Drying Conditions. 7th Int." In Congress on Agricultural Mechanization and Enerdy, 565-69.
• Yaldız, O. ve Ertekin, C. (2001) Thin layer solar drying of some vegetables, Drying Technology, 19, 583-97, doi: 10.1081/DRT-100103936