Study on Drying Kinetics of Paddy Rice: Intermittent Drying

Document Type : Research Article

Authors

School of Chemical Engineering, College of Engineering, University of Tehran, P.O. Box 11365-4563 Tehran, I.R. IRAN

Abstract

The intermittent drying characteristics of an Iranian popular paddy rice variety were experimentally investigated to determine the drying kinetics and obtain the effective moisture diffusivity. A lab-scale fluidized bed dryer was designed and constructed to enable obtaining the required results while controlling critical drying parameters. The effects of drying temperature and tempering period on drying kinetics and moisture diffusivity were studied. The results showed a significant effect on drying performance and effective moisture diffusivity by adding tempering stage. Drying rate improved sharply by implementing the tempering stage, increase of drying air temperature as well as the tempering duration.Several thin layer drying models were fitted separately to experimental data of each drying stages namely pre-tempering and post-tempering and suitability of these models were examined using the statistical analysis. The Midilli and Tow-Term model were found to be the most appropriate one for the first and second drying stages, respectively.

Keywords

Main Subjects


[1] Golmohammadi M., Rajabi-Hamane M., Hashemi S.J., Optimization of Drying–Tempering Periods in a Paddy Rice Dryer, Dry. Technol., 30(1):106-113 (2012).
[2] Golmohammadi M., Assar M., Rajabi-Hamane M., Hashemi, S.J.,Energy Efficiency Investigation of Intermittent Paddy Rice Dryer: Modeling and Experimental Study, Food Bioprod. Process., 94: 275-283 (2015).
[3] Golmohammadi M., Assar M., Rajabi-Hamane M., Experimental and Theoretical Investigation of Moisture Dynamics in Intermittent Drying of Rough Rice, J. Chem. Petrol. Eng., 46(2): 87-96 (2012).
[4] Pan Y.K., Zhao L.J., Dong Z.X., Mujumdar, A.S., Kudra T., Intermittent Drying of Carrot in a Vibrated Fluid Bed: Effect on Product Quality, Dry. Technol., 17(10): 2323-2340 (1999).
[5] Li Y.B., Cao C.W., Yu Q.L., Zhong Q.X., Study on Rough Rice Fissuring During Intermittent Drying, Dry. Technol., 17(9): 1779-1793 (1998).
[6] Jayas D.S., Cenkowski S., Pabis S., Muir W.E.,Review of Thin-Layer Drying and Wetting Equation,Dry. Technol., 9(3): 551-588 (1991).
[7] Agrawal Y.C., Singh R.P., Thin-Layer Drying Studies on Short-Grain Rice, ASAE Paper, No. 77-3531 (St. Joseph, MI, USA) (1977).
[8] Chandra P.K., Singh R.P., “Applied Numerical Methods for Food and Agricultural Engineers”, Boca Raton, CRC Press (1994).
[9] Wang C.Y., Singh R.P., A Single Layer Drying Equation for Rough Rice, ASAE Paper, 78:3001 (St. Joseph, MI, USA) (1978).
[10] Sharma A.D., Kunze O.R., Tolley H.D., Rough Rice Drying as a Two-Compartment Model, T. ASAE, 25: 221-224 (1982).
[11] Noomhorm A., Verma L.R., Deep-Bed Rice Drying Simulation Using Two Generalized Single-Layer Models, T. ASAE, 29: 1456-1461 (1986).
[12] Sharaf-Elden Y.I., Blaisdell J.L., Hamdy M.Y., A Model of Ear Corn Drying, T. ASAE, 23(5): 1261-1265 (1980).
[13] Doungporn S., Poomsa-ad N., Wiset L., Drying Equations of Thai Hom Mali Paddy by Using Hot Air, Carbon Dioxide and Nitrogen Gases as Drying Media, Food Bioprod. Process., 90(2):187-198 (2012).
[14] Midilli A., Kucuk H., Yapar Z., A New Model for Single Layer Drying, Dry. Technol., 20(7): 1503-1513 (2002).
[15] Henderson S.M., Pabis S., Grain Drying Theory I: Temperature Effect on Drying Coefficient, J. Agr. Eng. Res., 6(3): 169-174 (1961).
[16] Henderson S.M., Progress in Developing the Thin-Layer Drying Equation, T. ASAE., 17: 1167-1168 (1974).
[17] Verma R.L., Bucklin J.B., Endan J.B., Wratten F.T., Effects of Drying Air Parameters on Rice Drying models, T. ASAE.,28: 296-301 (1985).
[18] Kassem A.S., Comparative Studies on Thin Layer Drying Models for Wheat. In: Bartali E.H. (Ed.), “Proceeding of the 13th International Congress on Agricultural Engineering”, 2-6 February, Morocco, (1998).
[19] Prakash B., Pan Z., Effect of Geometry of Rice Kernels on Drying Modeling Results, Dry. Technol., 30(8): 801-807 (2012).
[20] Abbaszadeh A., Motevali A., Ghobadian B., Khoshtaghaza M.H., Minaei S., Effect of Air Velocity and Temperature on Energy and Effective Moisture Diffusivity for Russian Olive (Elaeagnusan Gastifolial L.) in Thin-Layer Drying,Iran. J. Chem. Chem. Eng. (IJCCE), 31(1): 75 -79 (2012).
[21] Foroughi-Dahr M., Golmohammadi M., Pourjamshidian R., Rajabi-Hamane M., Hashemi S.J., On the Characteristics of Thin-Layer Drying Models for Intermittent Drying of Rough Rice, Chem. Eng. Comm., 202(8): 1024-1035 (2015).
[22] Srisang N., Soponronnarit S., Thuwapanichayanan R., Prachayawarakorn S., Modelling Heat and Mass Transfer Induced Stresses in Germinated Brown Rice Kernels During Fluidized Bed Drying, Dry. Technol., 34(6): 619-634 (2016).
[23] ASAE Standards: Moisture Measurement–Unground Grains and Seeds, ASAE., (St. Joseph, MI, USA)(1996).
[24] Marinos-Kouris, D., Maroulis, Z.B., “Handbook of Industrial Drying”, CRC Press, , Boca Raton (2014).
[26] Malekjani N., Jafari S.M., Rahmati M.H., Esmaeelzadeh E., Mirzaee H., Evaluation of Thin-Layer Drying Models and Artificial Neural Networks for Describing Drying Kinetics of Canola Seed in a Heat Pump Assisted Fluidized Bed Dryer, Int. J. Food Eng., 9(4): 375-384 (2013).
[27] Bjőrck A., “Numerical Methods for Least Squares Problems”, SIAM, Philadelphia, (1996).
[28] Lopez A., Iguaz A., Esnoz A., Vírseda P., Thin-Layer Drying Behaviour of Vegetable Wastes from Wholesale Market, Dry. Technol., 18(4-5): 995-1006 (2000).
[29] Assar M., Golmohammadi M., Rajabi-Hamane M., Nabipoor Hassankiadeh M., A Combined Experimental and Theoretical Approach to Study Temperature and Moisture Dynamic Characteristics of Intermittent Paddy Rice Drying, Chem. Eng. Comm., 203(9): 1242-1250 (2016).