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標題: 乾燥條件對稻穀乾燥之影響
Effects of drying condition on rice curing
作者: Huang, I-Lin
關鍵字: Rice curing;稻穀乾燥;Drying condition;乾燥條件
出版社: 農業機械工程學系
率,以尋求最適之乾燥條件。 由加溫間歇式乾燥實
度45℃、相對濕度 2.7%、風量0.23 cmm/kg 時,各穀層之乾燥效果有較
%、風量 0.23cmm/kg之乾燥條件,其乾燥效果可達到穀層厚度50公分處
牛頓修正模式之預測值高度相關,決定係數 R-square皆達0.99以上;模
散模式皆適稱,其決定係數 R-square皆達0.99以上。 當通風溫
下降,當溫度為50℃時約下降 2%。對於厚層乾燥而言,完整米率將隨著

In this research, the effects of the hot-air conditions on
rice mechanical curing are studied. The investigating parameters
include the hot-air temperature, the relative humidity and the
air flow rate. By using a stationary type drying machine to cure
rice of 50 cm deep layer, the optimum drying conditions are
obtained through the analysis of the drying phenomenon and the
milling yields in different rice layers.
The result of the the intermittent drying test (15 min drying
time / 75 min drying time) indicate that the hot-air temperature
and the relative humidity has significant influence on the
drying rate, yet the effect of the air flow rate is secondary as
the depth of the layer lower than 10 cm. A better drying
condition of the hot-air temperature 45℃, relative humidity
2.7% and air flow rate 0.23 cmm/kg is obtained. This condition
can better cure rice more uniformly up to layer depth of 30 cm.
For the continuous drying test, the best drying condition of air
temperature 30℃, relative humidity 8.7%RH and air-flow rate
0.23cmm/kg is demonstrated. This drying condition can raise the
drying ability dramatically and uniformly cover the drying layer
up to 50cm. The drying time is also reduced as compared to the
former tempering test. When the layer depth
lower than 10 cm, the intermittent and continuous drying tests
are in consistent with the thin layer model. For the
intermittent drying experiment, the modified Newton's model can
precisely predict the moisture content change and all the
coefficients of determination R-square are larger than 0.99.
Using the multiple linear regression principle, the relations of
parameters A(constant coefficient) and k(drying constant) relate
to the hot-air drying conditions are established respectively.
Both equations are highly correlated to the drying conditions
performed, and the multiple correlation coefficients of this two
cases are higher than 92%. During the continuous drying
processes, the moisture content changes can be accurately
predicted from equations respectively derived from the modified
Newton's model and the diffusion model. It is found that the
diffusion equation is more suitable on this case and all the
coefficients of determination arelarger than 99%. The
experimental results also show that the milling property of rice
is not affected by temperature lower than 40℃ and the value of
head yield is up to 71% as the drying layer lower than 10 cm.
When the hot-air temperature increases over 45℃, the head yield
rate rapidly drops and the dropping value is about 2% at
temperature 50℃. In the deep layer drying, the head yield rate
is raised as the depth of drying layer increased.
Appears in Collections:生物產業機電工程學系

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