深床缓苏干燥工艺条件对稻谷干燥特性及爆腰增率的影响

Effect on Drying Characteristics and Additional Crack Percentage of Paddy Rice under the Tempering Drying Process Conditions in Deep Bed

应用热风干燥试验台进行缓苏干燥试验,研究稻谷深床缓苏干燥特性及品质变化。分析不同缓苏温度(20,30,40,50,60℃)、缓苏时间(1.5,3,6,9,12h)、缓苏方式(停风保温、通风保温、停风停温、低风停温、通风停温)、缓苏时刻(每层稻谷的含水率达到18%时)、缓苏含水率(16%、17%、18%、19%、20%)等因素对稻谷深床缓苏干燥特性及爆腰增率的影响,并探究现象产生的原因。试验结果表明:缓苏温度40℃、缓苏时间3h、缓苏方式为停风保温的条件下,当第3层稻谷含水率达到18%(w.b)时加入缓苏工艺,可有效提升稻谷干燥速率,缩短净干燥时间,提升干燥品质。整个干燥过程表现为降速干燥,在干燥过程最初的60~65min内干燥速率最快。缓苏方式的改变是影响稻谷缓苏干燥品质的最主要因素,停风保温的缓苏操作方式可以显著降低稻谷的爆腰增率,缓苏温度、缓苏时间、缓苏时刻及缓苏含水率对稻谷干燥品质均有显著影响。该研究结果更全面合理地解释稻谷缓苏干燥工艺参数的配合,为稻谷干燥的生产、工艺参数优化及确定最佳的缓苏条件以提高干燥品质提供理论依据与技术支持。

The characteristics and quality changes of deep bed tempering drying of rice were studied by hot air drying test bed.Analyzing different tempering temperatures(20,30,40,50,60℃),tempering times(1.5,3,6,9,12h),tempering methods(Stop the wind heat preservation,Ventilation and heat preservation,Stop the wind stop temperature,Low wind heat preservation,Wind and stop temperature),tempering moments(when the moisture content of rice each layer reaches 18%),tempering moisture contents(16%,17%,18%,19%,20%)under the condition of the tempering drying characteristics and additional crack percentage,and to explore the causes of the phenomenon.The test results showed that,tempering time 3h,stop the wind heat preservation and adding tempering process when the moisture content of the third layer reached 18%(w.b)under the conditions of tempering temperature 40℃,the drying rate of rice could be effectively improved,and the pure drying time could be shortened and the drying quality could be promoted.The whole drying process was characterized by slow drying,and the drying rate was the fastest in the first 60-65min of drying process.The change of tempering method was the main factor affecting rice tempering drying quality.The tempering method could significantly reduce the additional crack percentage,and the tempering temperature,tempering time,tempering moment and tempering moisture content all have significant effects on rice drying quality.The results of this study could provide a more comprehensive and reasonable explanation for the coordination of technological parameters of rice tempering drying,and provide theoretical basis and technical support for the production of rice drying,the optimization of technological parameters and the determination of the best tempering drying conditions to improve the drying quality.