Study on the early detection of grain spoilage in the drying facility

近年来，烘干设备经常发生粮食腐败事故。在第一章中，将腐败分为化学、生理和生物三个方面。研究发现，每一次腐烂过程中，二氧化碳浓度都会增加。因此，通过分析储粮仓内二氧化碳浓度的变化来检测粮食变质是有可能的。第三章研究发现，粮食含水率越高，储藏温度越高，仓内二氧化碳浓度增加的速率越大。第四章考察了收割后的处理条件，如粮食含水率、温度等对粮食腐败的影响。以二氧化碳浓度和颗粒表面颜色为腐败指标。然而，没有发现它们之间的相关性。第五章利用模型试验对露水凝结腐败的检测进行了研究。当储粮中有0.04%的露水凝结时，可检测到仓内二氧化碳浓度。第六章，在实际仓储中，对堆放的粮食进行了湿粮检测试验。可以测量到二氧化碳浓度的变化，识别出粮食变质的迹象。然而，二氧化碳在颗粒层中的扩散速率很低。第七章对自下而上曝气的效果进行了测试。这可能会使扩散速度很快，因此在很短的时间内就可以检测到实际储存箱中的二氧化碳。

Recently, the accident of grain spoilage often occurs in the drying facility. In chapter 1, the spoilage was classified to chemical, physiological and biological aspects. It was found that the carbon dioxide concentration increases in every spoilage. So, there is a probability to detect the grain spoilage by analyzing the change of carbon dioxide concentration in the storage bin. In chapter 3, It was found that the higher the grain moisture content is, and the higher the storage temperature is, the more the increasing rate of the carbon dioxide concentration became in the bin. It was then judged that the grain spoilage can be detected by the measurement of change of carbon dioxide concentration, In chapter 4, the effect of the treatment condition after harvesting, for example grain moisture content, temperature, on the grain spoilage was surveyed. The indices of spoilage were the carbon dioxide concentration and grain's surface color. However, the correlation between them could not be found. In chapter 5, the detection of spoilage caused by dew condensation was considered using the model test. When 0.04 % of the stored grain was affected by dew condensation, the carbon dioxide concentration could be detected in the bin. In chapter 6, in the actual storage bin, the detection test was done setting the wet grain on the piled grain. The change of carbon dioxide concentration could be measured, and the sign of grain spoilage was recognized. However, the diffusion rate of carbon dioxide was low through the grain layr. In chapter 7, the effect of aeration from bottom to top was tested. That could make the diffusion rate high, so the detection of carbon dioxide in the actual storage bin became possible within short time.