Experimental research on drying technology for high moisture content paddy

Aiming at the market demand that high moisture content paddy must be dried in time during the harvest in the south of China, three kinds of drying technologies, namely, low constant temperature drying, variable temperature drying and adding tempering time during variable temperature drying, were tested on the circulating batch paddy dryer. On the basis of tested results, interrelationship and interaction among parameters, such as paddy moisture, air temperature, paddy temperature, the ratio of tempering time to drying time etc., were analyzed. Tested results show that when the moisture content of paddy is higher than 21%, the drying rate can exceed 1%/h and 60～70℃ air temperature can be used. When the moisture content of paddy is lower than 18%, air temperature should be lower than 60℃ and the drying rate should be less than 1%/h. After three to four times drying and tempering for high moisture content paddy, adding tempering time by using middle tempering barn, temperature and moisture inside and outside paddy can tend to reach an equilibrium state, which is beneficial to improved drying quality of paddy and next drying process. Conclusions in this paper have practical value for drying technology design and equipment development for the high moisture content paddy.