热风温度对种子稻谷干燥速率与发芽率的影响
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摘要
我国是农业大国，人口众多，由于经济的需要，耕地逐年在减少，粮食的生产也随之减少。而我国每年收获的粮食出于各种原因，损失相当惊人。因此，确保现有耕地所产粮食少受甚至不受损失，至关重要。有效的方法是普及粮食干燥机。随着干燥机的普及，面临着干燥机的使用问题。既要保证干燥后粮食的品质又要注意能源及产量不必要的损失。因此，干燥粮食时采用合理的工艺流程，选择合适的干燥参数，对保证粮食干燥后的品质具有重要意义。
本试验是在实际干燥生产中进行的，利用本单位的种子干燥机，在干燥过程中测取干燥参数，进行种子稻谷的干燥试验。旨在实际干燥过程中，通过不同的干燥条件，了解干燥过程各参数之间的关系，为今后的干燥工作提出指导意见。
试验结果表明稻谷含水率随干燥时间的延长而平稳降低，呈减速趋势。高水分稻谷在干燥前一段时间降水较大，呈等速趋势，含水率达一定值后，降水又呈减速趋势。干燥时间与含水率的关系近似线性关系，可用回归方程M=at+b来描述。
干燥过程中，稻谷经过一段预热升温时间后，达到某一值便不会随干燥时间的延长而升高，总在某一值上波动，且波动幅度很小。一般情况下，干燥温度高，稻谷温度也高。因此可用调整热风温度的方法来控制稻谷的温度。
谷物平均温度随热风温度的升高而逐渐增加；谷物的平均干燥速率随热风温度的提高而增大。
随着热风温度的提高，稻谷平均发芽率损失有比较明显的增大趋势。当谷物温度达到34℃以上时，种子发芽率损失明显增大。相同干燥条件下，所用干燥时间比较多的批次，其发芽率损失比所用干燥时间少的要低。干燥过程中，干燥速率越大，发芽率损失也越大；稻谷初始含水率越大，发芽率损失也越大；相同热风温度下，干燥数量越少，其谷物温度就越高，干燥速率就越大，发芽率损失也越大。
在实际干燥工作中设定合适的热风温度。在干燥过程中，根据干燥情况调整热风温度，在不影响稻谷品质的前提下，提高干燥机的工作效率，减少不必要的能源消耗。
China is a big country with huge populations. The demand by economic development led to the decrease of farming land and thereby reduced crop yield year by year. On the other hand, annual grain loss due to various reasons is huge. Hence, it is acute importance to avoid the harvested grain loss. An effective measure is to extend grain drying machines. As drying machines are extended, the problem of drying machine operation appears. Attention not only should be paid on the quality of the dried grain, but also on economic energy consumption and reduced loss. Thus selection of reasonable drying technique and suitable drying parameters is an important guarantee for a better drying quality.
The experiment was conducted during a real drying process. Using our own drying machine, we measured some drying parameters and experimented on the drying machines. The aim of this work is to learn the relationships between various parameters in drying procedure, so as to provide constructive opinion for the future improvement work.
Results showed that grain water content steadily decrease with the time elapse, showing a decreasing trends. High water content grain lose water in a higher rate, having a steady rate, and when reaching a certain water content, turning into a decreased water losing rate. A linear relationship is noticed between drying time elapse and grain water content, a regression formula of M = at + b is suitable for expressing such a relationship.
During the drying process, temperature of grain do not surge after an initial stage of pre-heating period, it fluctuates around a value but with a little degree. In general, higher drying temperature results into higher grain temperature. So that the control of grain temperature can be realized by the adjustment of the temperature of hot air.
Average grain temperature increases as the temperature of the hot air increases, so is average drying rate.
As the hot air temperature increases, the germinating rate is obviously impaired. When grain temperature is raised above 34C, seed germinating rate is clearly reduced. On the same drying conditions, the batch with longer drying period will have a lower germinating rate compared with the shorter drying period. A higher drying rate results into more reduced germinating rate. A higher initial water content relates to more reduced germinating rate. On
the same hot air temperatures, reduced drying quantities relates to increased grain temperatures and higher drying rates, resulting into higher loss of germinating.
In the drying process the hot air temperature should be properly adjusted. Depending on the drying conditions in the real practice, regulation of hot air temperature should be performed, so that no negative effect happens on paddy seed quality and the working efficiency of drying machine is increased, avoiding energy loss is reached.
本试验是在实际干燥生产中进行的，利用本单位的种子干燥机，在干燥过程中测取干燥参数，进行种子稻谷的干燥试验。旨在实际干燥过程中，通过不同的干燥条件，了解干燥过程各参数之间的关系，为今后的干燥工作提出指导意见。
试验结果表明稻谷含水率随干燥时间的延长而平稳降低，呈减速趋势。高水分稻谷在干燥前一段时间降水较大，呈等速趋势，含水率达一定值后，降水又呈减速趋势。干燥时间与含水率的关系近似线性关系，可用回归方程M=at+b来描述。
干燥过程中，稻谷经过一段预热升温时间后，达到某一值便不会随干燥时间的延长而升高，总在某一值上波动，且波动幅度很小。一般情况下，干燥温度高，稻谷温度也高。因此可用调整热风温度的方法来控制稻谷的温度。
谷物平均温度随热风温度的升高而逐渐增加；谷物的平均干燥速率随热风温度的提高而增大。
随着热风温度的提高，稻谷平均发芽率损失有比较明显的增大趋势。当谷物温度达到34℃以上时，种子发芽率损失明显增大。相同干燥条件下，所用干燥时间比较多的批次，其发芽率损失比所用干燥时间少的要低。干燥过程中，干燥速率越大，发芽率损失也越大；稻谷初始含水率越大，发芽率损失也越大；相同热风温度下，干燥数量越少，其谷物温度就越高，干燥速率就越大，发芽率损失也越大。
在实际干燥工作中设定合适的热风温度。在干燥过程中，根据干燥情况调整热风温度，在不影响稻谷品质的前提下，提高干燥机的工作效率，减少不必要的能源消耗。
China is a big country with huge populations. The demand by economic development led to the decrease of farming land and thereby reduced crop yield year by year. On the other hand, annual grain loss due to various reasons is huge. Hence, it is acute importance to avoid the harvested grain loss. An effective measure is to extend grain drying machines. As drying machines are extended, the problem of drying machine operation appears. Attention not only should be paid on the quality of the dried grain, but also on economic energy consumption and reduced loss. Thus selection of reasonable drying technique and suitable drying parameters is an important guarantee for a better drying quality.
The experiment was conducted during a real drying process. Using our own drying machine, we measured some drying parameters and experimented on the drying machines. The aim of this work is to learn the relationships between various parameters in drying procedure, so as to provide constructive opinion for the future improvement work.
Results showed that grain water content steadily decrease with the time elapse, showing a decreasing trends. High water content grain lose water in a higher rate, having a steady rate, and when reaching a certain water content, turning into a decreased water losing rate. A linear relationship is noticed between drying time elapse and grain water content, a regression formula of M = at + b is suitable for expressing such a relationship.
During the drying process, temperature of grain do not surge after an initial stage of pre-heating period, it fluctuates around a value but with a little degree. In general, higher drying temperature results into higher grain temperature. So that the control of grain temperature can be realized by the adjustment of the temperature of hot air.
Average grain temperature increases as the temperature of the hot air increases, so is average drying rate.
As the hot air temperature increases, the germinating rate is obviously impaired. When grain temperature is raised above 34C, seed germinating rate is clearly reduced. On the same drying conditions, the batch with longer drying period will have a lower germinating rate compared with the shorter drying period. A higher drying rate results into more reduced germinating rate. A higher initial water content relates to more reduced germinating rate. On
the same hot air temperatures, reduced drying quantities relates to increased grain temperatures and higher drying rates, resulting into higher loss of germinating.
In the drying process the hot air temperature should be properly adjusted. Depending on the drying conditions in the real practice, regulation of hot air temperature should be performed, so that no negative effect happens on paddy seed quality and the working efficiency of drying machine is increased, avoiding energy loss is reached.
引文
1 蓝卫星．粮食作物干燥技术及其发展趋势．广西农业机械化．2002，6：11-13
2 荣兰荪，杨衍有．国外粮食干燥技术及进展．粮食干燥技术(二)．商业部郑州粮食科研设计所，全国粮仓机械情报中心站．参考资料第89号，干燥专题资料之二．1984
3 陈坤杰．稻谷平床深层干燥试验研究，[学位论文]，南京，南京农业大学，2000
4 Agrawal Y C,,Singh R P.Thin. Layer Drying Studies on Short-grain Rough Rice. ASAE Paper 77-3531,1977
5 Crank J.The Mathematice of Diffusion.Oxford:Clarendon Press,1997
6 Page G.Factots Influencing the Max Rate of Air Drying Shelled Corn in Thin Layer.M.S Thesis,Purdue University,1949
7 魏纳尔．米勒保尔等著，谢桂芳，丁声俊等译．国外粮食干燥技术集锦．中国财歧经济出版社，1989
8 Thompson T L.Mathematicai Simulation of Corn Drying-A New Model.Transaction of ASAE,1968,11(4):582-586
9 Wang C Y,Singh R P.A Single Layer Drying Equation for Rough Rice.ASAE Paper 78-3001,1978
10 Bakker-Artema F W.Grain Dryer Simulation.Research Report of MSU, 1974
11 曹崇文．粮食干燥系统的计算机模拟及其应用．南京林业大学学报．第21卷增刊，156-160
12 邵耀坚等．谷物干燥机原理与构造．北京：机械工业出版社，1985
13 李笑光．农作物干燥与通风贮藏．天津科学技术出版社，1989
14 连政国等．顺流干燥种子发芽率的预测．农业工程学报，第15卷，2：198-201
15 朱文学．干燥过程中谷物应力裂纹和发芽率的模拟与试验研究．[学位论文]，北京，中国农业大学．1997
16 李娟玲等．固定床深层干燥稻谷爆腰增率及发芽率试验研究．粮食与饲料工业．2001，12：9-11
2 荣兰荪，杨衍有．国外粮食干燥技术及进展．粮食干燥技术(二)．商业部郑州粮食科研设计所，全国粮仓机械情报中心站．参考资料第89号，干燥专题资料之二．1984
3 陈坤杰．稻谷平床深层干燥试验研究，[学位论文]，南京，南京农业大学，2000
4 Agrawal Y C,,Singh R P.Thin. Layer Drying Studies on Short-grain Rough Rice. ASAE Paper 77-3531,1977
5 Crank J.The Mathematice of Diffusion.Oxford:Clarendon Press,1997
6 Page G.Factots Influencing the Max Rate of Air Drying Shelled Corn in Thin Layer.M.S Thesis,Purdue University,1949
7 魏纳尔．米勒保尔等著，谢桂芳，丁声俊等译．国外粮食干燥技术集锦．中国财歧经济出版社，1989
8 Thompson T L.Mathematicai Simulation of Corn Drying-A New Model.Transaction of ASAE,1968,11(4):582-586
9 Wang C Y,Singh R P.A Single Layer Drying Equation for Rough Rice.ASAE Paper 78-3001,1978
10 Bakker-Artema F W.Grain Dryer Simulation.Research Report of MSU, 1974
11 曹崇文．粮食干燥系统的计算机模拟及其应用．南京林业大学学报．第21卷增刊，156-160
12 邵耀坚等．谷物干燥机原理与构造．北京：机械工业出版社，1985
13 李笑光．农作物干燥与通风贮藏．天津科学技术出版社，1989
14 连政国等．顺流干燥种子发芽率的预测．农业工程学报，第15卷，2：198-201
15 朱文学．干燥过程中谷物应力裂纹和发芽率的模拟与试验研究．[学位论文]，北京，中国农业大学．1997
16 李娟玲等．固定床深层干燥稻谷爆腰增率及发芽率试验研究．粮食与饲料工业．2001，12：9-11