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United States Department of Agriculture

Agricultural Research Service


item Khir, Ragab
item Pan, Zhongli - John
item Salim, Adel

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 12/1/2005
Publication Date: N/A
Citation: N/A

Interpretive Summary: There is a great need to develop new rice drying technologies with high process and energy efficiencies. In this research, the drying rates of thin layer rice drying were studied. The results showed that high drying rate and short drying time can be achieved by using infrared with thin layer drying. The obtained results are very important information for new infrared dryer design.

Technical Abstract: Rice drying with infrared radiation has been investigated during recent years and showed promising potential with improved quality and energy efficiency. However, due to limited penetration capability of infrared radiation, thin layer drying may be used in infrared dryer design. The objective of this study was to study the moisture removal of thin layer rice during infrared heating followed by various cooling methods, including natural cooling, forced-air cooling and vacuum cooling. The rewetted rough rice samples with four different moisture contents, 20%, 25%, 30%, and 35%, were dried with four different radiation intensities, 3616, 4023, 4685, and 5348 W/m2, for four exposure times, 30, 60, 90, 120 sec. The achieved grain temperatures ranged from 34ºC to 68ºC under the tested heating conditions. The vacuum cooling showed more moisture removal than both forced-air cooling and natural cooling. The total moisture removal reached to 3.4%, 3.3%, and 2.1% for heating with 5348 W/m2 for 120 sec and rice temperature of 68°C and followed by vacuum cooling for ten minutes, forced ambient air cooling for five minutes and natural cooling for twenty minutes, respectively. It was concluded that thin layer drying using infrared radiation followed by cooling could be an effective approach for infrared rice dryer design.

Last Modified: 10/16/2017
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