Main Article Content



A mathematical model developed by Nellist et al. (1987) was adopted in this continuous two dimensional spouted bed dryer (2DSB) configuration. The objective of this research was to predict air temperature, grain temperature, absolute humidity and moisture content during the drying process in 2DSB. In simulation, spouted bed was divided into two regions which were spout and downcomer regions. Air and grains in spout and downcomer were assumed to be moving with co- and counterflow principles. During experiments, drying air temperature at 80oC and different paddy initial moisture contents (at 41% db, 36% db and 30% db) were used. Based on data, the air temperature profiles in spout region showed that air temperature dropped significantly with the axial positions while downcomer regions resulted fluctuated value. The average deviation of the air temperature in the spout was less than 4.5% and within downcomer was less than 4.2%. Grain temperature and absolute humidity in spout region increased slowly whilst decreasing in steps in downcomer regions with axial position. The moisture content decreased both in spouted and downcomer regions. Moisture reduction in spout region was higher than downcomer regions because of the high air flow rate in spout region.


Penelitian ini menggunakan model matematika yang dikembangkan oleh Nellist et al. (1987) untuk pengering spouted bed dua dimensi tipe kontinyu. Tujuan dari penelitian ini adalah menduga sebaran suhu udara, suhu gabah, kelembaban mutlak udara dan kadar air selama proses pengeringan. Pada proses simulasi, ruang pengering dibagi menjadi dua daerah yaitu daerah spout dan daerah downcomer. Udara dan bahan di daerah spout dan downcomer diasumsikan bergerak dengan prinsip aliran co- dan counterflow. Suhu udara yang digunakan selama pengujian adalah suhu 80oC dengan kadar air awal bahan yang berbeda-beda yaitu 41% bk, 36% bk dan 30% bk. Dari data pengujian menunjukkan bahwa suhu udara di daerah spout akan menurun secara signifikan terhadap posisi aksial ruang pengering tetapi pada daerah downcomer suhu udara bernilai fluktuatif. Nilai rataan deviasi pada pendugaan suhu udara daerah spout bernilai kurang dari 4.5% dan pada daerah downcomer deviasi bernilai kurang dari 4.2%. Suhu gabah dan kelembaban mutlak udara pada daerah spout menunjukkan bahwa nilai akan naik secara bertahap sementara untuk daerah downcomer nilai menurun secara bertahap terhadap posisi aksial. Penurunan kadar air menunjukkan bahwa untuk daerah spout dan daerah downcomer mengalami penurunan nilai. Penurunan kadar air daerah spout lebih besar dibandingkan daerah downcomer karena pada daerah spout laju aliran udara lebih besar.


Mathematical model moisture content paddy two dimensional spouted bed dryer

Article Details


  1. Boyce, D.S. 1965. Grain moisture and temperature changes with position and time during through drying. Journal of Agricultural Engineering Research. 10:333-341.
  2. Freitas, L.A.P., J.T. Freire. 1997. Experimental study on the dynamics of a draft tube spouted bed with continuous solids feeding. Brazilian Journal
  3. Chemical Engineering. 4(3):269-280.
  4. Gallaghan, G.L. 1951. A method of determining the latent heat of agricultural crops. Journal Agricultural Engineering. 32(1):34-38.
  5. Gisler, P.E. 1983. The spouted bed technique – discovery and early study at NRC. Canadian Journal Chemical Engineering. 267-268.
  6. Laithong, C. 1987. Study of thermo-physical properties of rough rice. M. Sc. Thesis. King Mongkut’s Institute of Technology Thonburi. Thailand.
  7. Madhiyanon, T., S. Somchart, T. Warunee. 2007. A Mathematical model for continuous drying of grains in a spouted bed dryer. Drying Technology: An International Journal. 587-614.
  8. Nellist, M.E., R.D. Whitfield, J.A. Marchant. 1987. Computer simulation and control of grain drying, in J.A., Clark., K. Gregson dan R.A. Saffell. Computer applications in Agricultural Environments. UK. p 127-142.
  9. O’Collaghan, J.R., D.J. Menzies dan P.H. Bailey. 1971. Digital simulation of agricultural drier performance. Journal of Agricultural Engineering
  10. Research. 16:223-244.
  11. Viswanathan, K., M.S. Lyall, Raychaudhuri. 1986. Agricultural grains spouted bed drying. Canadian Journal Chemical Engineering. 64:223-232.
  12. Wiset, L., G. Srzednicki, R. Driscoll, C. Nimmuntavin dan P. Siwapornrak. 2001. Effects of High Temperature Drying on Rice Quality. Agricultural
  13. Engineering International: the CIGR Journal of Scientific Research and Development. Manuscript FP 01 003.
  14. Zahed, AH., N. Epstein. 1992. Batch and continuous spouted bed drying of cereal grains : the thermal equilibrium model. The Canadian Journal of
  15. Chemical Engineering. 70(5):945-953.