EFFECTS OF RESTING PERIODS, AIR TEMPERATURES, AND AIR VELOCITIES ON FREE-FALL PADDY DRYER PERFORMANCES
Keywords:
Free-fall dryer, energy consumption, milled rice quality, glass transition temperatureAbstract
The free- fall paddy dryer has been recently invented and patented by the second author.This paper reports the results of the investigation into the drying rates, the primary specific energy consumption of the dryer, and the resulting rice quality including head rice yields and whiteness of milled rice. The following drying conditions were used: air temperatures of 40, 60, 100, 130, and 150oC; drying air velocities: 1, 2, and 3 m s-1; and rest periods: 0, 1,2, and 4 min. Test results showed that the dryer consumed quite low energy, of the order of 2- 4 mega joules per kilogram of water evaporated. In addition, the rest periods higher than 1 min could maintain the amount of head rice yields and whiteness levels similar to those of the reference sample ( ambient drying) . Thus, high milled rice qualities and low energy consumption could be achieved in a single drying process.
References
AACC. (1995). Approved Method of the AmericanAssociation of Cereal Chemists. 9th ed. AmericanAssociation of Cereal Chemists, St. Paul, MN,USA.
Aquerreta, J., Iguaz, A., Arroqui, C., and Virseda, P.(2007). Effect of high temperature intermittentdrying and tempering on rough rice quality. J. FoodEng., 80: 611-618.
Chitra, B. (1989). The study of rice qualities from paddiesat different moisture levels. BS report. Departmentof Science, Petchaburiwittayalongorn College,Petchaburi, Thailand.
Chitsomboon, T., Khaengkarn, S., and Pechnumkheaw, K.(2006). Free-fall-paddy rice dryer: A fast andenergy efficient dryer. Proceedings of the 2ndConference on Energy Technology Network ofThailand; Nakhon Ratchasima, Thailand.
Chua, K.J., Mujumdar, A.S., and Chou, S.K. (2003).Intermittent drying of bioproducts - an overview.Bioresource Technol., 90:285-295.
Chungcharoen, T., Prachayawarakorn, S., Tungtrakul, P. ,and Soponronnarit, S. (2015). Effects ofgermination time and drying temperature on dryingcharacteristics and quality of germinated paddy.Food Bioprod. Process., 94:707-716.
Cnossen, A.G. and Siebenmorgen, T.J. (2000). The glasstransition temperature concept in rice drying andtempering: Effect on milling quality. T. ASAE,43(6):1661-1667.
Cnossen, A.G., Siebenmorgen, T.J., and Yang, W. (2002).The glass transition temperature concept in ricedrying and tempering: Effect on drying rate. T.ASAE, 45(3):759-766.
Department of Intellectual Property of Thailand. (2007).Patent Title: Vertical counter flow dryer type.Registration Number 22985, Registration Date Dec.27th, 2007.
Dong, R., Lu, Z., Liu, A., Nishiyama, Y., and Cao, W.(2009). Moisture distribution in a rice kernel duringtempering drying. J. Food Eng., 91:126-132.
Dong, R., Lu, Z., Liu, Z., Koide, S., and Cao, W. (2010).Effect of drying and tempering on rice fissuringanalysed by integrating intra-kernel moisturedistribution. J. Food Eng., 97:161-167.
Ferry, J.D. (1980). Viscoelastic Properties of Polymers. 3rded. John Wiley, NY, USA, 476p.
Golmohammadi, M. , Assar, M. , Rajabi- Hamane, M.,and Hashemi, S.J. (2015). Energy efficiencyinvestigation of intermittent paddy rice dryer:Modeling and experimental study. Food Bioprod.Process., 94:275-283.
Jia, C.C., Yang, W., Siebenmoregen, T.J., Bautista, R.C.,and Cnossen, A.G. (2002). A study of rice fissuringby finite element simulation of internal stressescombined with high-speed microscopy imaging offissure appearance. T. ASAE, 45:741-749.
Li, Y.B., Cao, W.C., and Zhong, Q.X. (1999). Study onrough rice fissuring during intermittent drying. DryTechnol., 17(9):1779-1793.
Li, X. J. , Wang, X. , Li, Y. , Jiang, P. , and Lu, H. ( 2016) .Changes in moisture effective diffusivity and glasstransition temperature of paddy during drying.Comput. Electron. Agric., 128:112-119.
Madhiyanon, T., Soponronnarit, S., and Tia, W. (2002). Amathematical model for continuous drying of grainsin a spouted bed dryer. Dry Technol. , 20(3):587-614.
Madhiyanon, T. and Soponronnarit, S. (2005). Hightemperature spouted bed paddy drying with varieddowncomer air flows and moisture contents:Effects on drying kinetics, critical moisture content,and milling quality. Dry Technol., 23:473-495.
Nishiyama, Y., Cao, W., and Li, B. (2006). Grainintermittent drying characteristics analyzed bya simplified model. J. Food Eng., 76:272-279.
Ondier, G.O., Siebenmorgen, T.J., and Moustakos, A.M.(2012). Drying characteristics and milling qualityof rough rice dried in a single pass incorporatingglass transition principles. Dry Technol., 30:1821-1830.
Patindol, J. and Wang, Y.J. (2002). Fine structures ofstarches from long-grain rice cultivars withdifferent functionality. Cereal Chem. , 79(3):465-469.
Perdon, A.A., Siebenmorgen, T.J., and Mauromoustakos,A. ( 2000) . Glassy state transition and rice drying:Development of a brown rice state diagram. CerealChem., 77:708-713.
Poomsa-ad, N., Soponronnarit, S., Prachayawarakorn, S.,and Terdyothin, A. (2002). Effect of tempering onsubsequent drying of paddy using fluidizationtechnique. Dry Technol., 20(1):195-210.
Poomsa-ad, N., Terdyothin, A., Prachayawarakorn, S., andSoponronnarit, S. ( 2005) . Investigations on headriceyield and operating time in the fluidised- beddrying process: Experiment and simulation. J.Stored Prod. Res., 41:387-400.
Prachayawarakorn, S., Poomsa-ad, N., and Soponronnarit,S. (2005a). Quality maintenance and economy withhigh-temperature paddy-drying process. J. StoredProd. Res., 41:333-351.
Prachayawarakorn, S., Tia, W., Poopaiboon, K., andSoponronnarit, S. (2005b). Comparison ofperformances of pulsed and conventional fluidisedbeddryers. J. Stored Prod. Res, 41:479-497.
Sarker, M.S.H., Ibrahim, M.N., Aziz, N.A., and Salleh,P.M. (2014). Energy and rice quality aspects duringdrying of freshly harvested paddy with industrialinclined bed dryer. Energ. Convers. Manage.,77:389-395.
Sarker, M.S.H., Ibrahim, M.N., Aziz, N.A., and Punan,M.S. (2015a). Application of simulation indetermining suitable operating parameters forindustrial scale fluidized bed dryer during drying ofhigh impurity moist paddy. J. Stored Prod. Res. ,61:76-84.
Sarker, M.S.H., Ibrahim, M.N., Aziz, N.A., and Punan,M.S. (2015b). Energy and exergy analysis ofindustrial fluidized bed drying of paddy. Energy,84:131-138.
Siebenmorgen, T.J., Wang, W., and Sun, S. (2004). Glasstransition temperature of rice kernels determined bydynamic mechanical thermal analysis. T. ASAE,47(3):835-839.
Siebenmorgen, T. (2013). Laboratory measurement of ricemilling yield. In: Arkansas Rice ProductionHandbook. 1st ed. Hardke, J.T., (ed). University ofArkansas Division of Agriculture CooperativeExtension Service, Little Rock, AR, USA, p. 167-175.
Soponronnarit, S. (1997). Drying Grains and Some Typesof Foods. King Mongkut’s University ofTechnology Thonburi, Bangkok, Thailand, 338p.(in Thai)
Sun, Z., Yang, W., Siebenmorgen, T.J., Stelwagen, A.M.,and Cnossen, A.G. (2002). Thermomechanicaltransitions of rice kernels. Cereal Chem., 79:349-353.
Tohidi, M., Sadeghi, M., and Torki-Harchegani, M.(2017). Energy and quality aspects for fixed deepbed drying of paddy. Renew. Sust. Energ. Rev.,70:519-528.
Wansuksri, R., Ninchan, B., Piyachomkwan, K., Suntisopasri,V., Petchalanuwat, C., and Sriroth, K. (2005).Correlation between physico-chemical propertiesand molecular structure of rice starches.Proceedings of the 43rd Kasetsart University AnnualConference: Animals, Agro- Industry; February1-4, 2005; Bangkok, Thailand, p. 649-659. (in Thai)
Zhang, Q., Yang, W., and Jia, C.C. (2003). Preservation ofhead rice yield under high-temperature temperingas explained by the glass transition of rice kernels.Cereal Chem., 80(6):684-688.
