小麦气调储藏环境中氮气传递规律的研究

Pattern of Nitrogen Migration in a Modified Atmosphere Environment for Wheat Storage

本实验在长9 m,宽6 m,高9 m的模拟中试仓,设计装粮线6.0 m,实储小麦高度5.7 m,N_2流量为30 L/m^3,恒定通入仓内。粮情测控智能终端测定18 min/次,当各点N_2浓度最高且持续稳定,停止向仓内通入N_2。结果表明:通过从离送气口的对称点位测得N_2在仓内传递速度均匀,因此可以均匀布点进行。水平方向距离送气口越远,N_2传递速度越慢。垂直方向距离越远,N_2浓度上升的越慢;离送气口越近,点之间N_2浓度差越大;离送气口越远,检测点之间浓度变化越相似。各点时间-N_2浓度均成显著正相关(p<0.01),且检测点越接近,相关性越强,随着检测点之间距离的增加,相关性系数越来越小,说明N_2逐层传递,相邻检测点之间影响较大。通过对距离相同的水平与垂直检测点N_2浓度变化的分析,由显著性p=0.02(p<0.05)得到垂直方向N_2浓度变化显著快于水平方向N_2浓度变化。

The experiment was carried out in a simulated pilot warehouse（length 9 m, width 6 m, height 9 m）. The designed grain-piling line was 6 m, and the actual height of the wheat was 5.7 m. Nitrogen was constantly purged into the warehouse at a flow rate of 30 m^3/h. The storage conditions were monitored every 18 min by an intelligent terminal system, and nitrogen purging was stopped when the concentration at each point reached the highest level and was stable. The results showed that the nitrogen migration speeds in the warehouse measured at points symmetrical to the air supply inlet were almost the same, so the nitrogen migration speeds in different directions were compared by setting points evenly. In the horizontal direction, the further the measurement point was from the air supply inlet, the slower the nitrogen migration speed became. In the vertical direction, the further the measurement point was from the air supply inlet, the slower the increase in nitrogen concentration; the closer the points were to the air supply inlet, the more significant the difference in nitrogen concentration between points, and the further the points were, the more similar the changes in nitrogen concentration between points. The time and nitrogen concentration at each point showed a significant positive correlation（p〈0.01）. The closer two measurement points were, the stronger the correlation. With increasing distance between the measurement points, the correlation coefficient became smaller, indicating that nitrogen migration proceeded in layers, and neighboring points had a relatively greater impact. Analysis of the change in nitrogen concentration at vertical and horizontal points at the same distance showed that changes in the vertical direction were faster than those in the horizontal direction at a significance level of p=0.02.