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

近年来，粮食干燥设备中的粮食腐败事故时有发生。第一章从化学、生理和生物三个方面对食品腐败进行了分类。结果发现，在每个腐败的二氧化碳浓度增加。因此，有可能通过分析仓内二氧化碳浓度的变化来检测粮食的腐败变质。在第三章中，研究发现，粮食含水率越高，储藏温度越高，仓内二氧化碳浓度的增加速率越大。第四章考察了收获后处理条件（如谷物含水量、温度）对谷物腐败的影响。以CO2浓度和籽粒表面颜色为指标进行评价。在第五章中，我们利用模型试验的方法，对结露引起的腐坏进行了检测。当0.04%的储粮受结露影响时，仓内可检测到二氧化碳浓度。第六章在实际料仓中，将湿粮放置在粮堆上进行检测试验。通过测定谷物中CO2浓度的变化，可以识别谷物的腐败迹象。然而，二氧化碳通过颗粒层的扩散速率很低。第七章对自下而上曝气的效果进行了试验。这可以使扩散速率高，因此在短时间内检测实际存储仓中的二氧化碳成为可能。

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.