Macro-control of grain is the main means to maintain national food security, and grain depot is the basis of macro-control of grain. Therefore, the intelligent control and precise management of grain storage is the key to achieve safe and efficient grain storage.

Grain storage zui is mainly treated with insect removal. Aluminum phosphide is China's food sector to promote the application of a very effective stored grain insecticide, widely used in grain storage depot when water or moisture absorption can be deliquescent, release of highly toxic phosphine gas. The laboratory technician of the grain depot will be exposed to phosphine gas when sampling and testing and the storekeeper entering the depot to measure the temperature, humidity and check the grain situation and insect situation. Some of them cause phosphine poisoning due to lack of safety and health knowledge.

In order to investigate the concentration of phosphine in the granary during fumigation and the time after fumigation to below the national health standards, it is necessary to monitor the change of phosphine gas concentration and the concentration of O2, CO2 and other gases in the warehouse after fumigation, so as to provide a scientific basis for the protection of personnel health. During the fumigation period, the concentration of phosphine in the warehouse and the grain pile was very high, reaching a peak value in 48h in the warehouse and 96h in the grain pile, and the concentration of phosphine in the warehouse was much higher than that in the grain pile in the first two days. However, with the passage of time, the difference between the two became smaller and tended to be balanced, indicating that the phosphine produced by the deliquescence of aluminum phosphide quickly diffused in the warehouse and gradually diffused into the grain pile, and the concentration of phosphine in the warehouse dropped to near the national health standard two days after the warehouse was opened and vented. After the secondary closure of the warehouse, the concentration of phosphine in the grain pile gradually decreased, while in the warehouse it increased first and then decreased, indicating that after the secondary closure of the warehouse, the phosphine in the grain pile was gradually released to the space in the warehouse, causing the concentration in the warehouse to increase. It was not until the 9th day that the concentration of phosphine in the grain pile and warehouse fell below the national health standard. It is safer to enter the warehouse after about half a month from the beginning of opening and venting after fumigation.

On the basis of the existing digital temperature measurement, the grain situation measurement and control early warning module of the storage business management system should also integrate the automatic analysis functions of the detection of gas, humidity and insect pests in the grain pile, and the measured data should be written into the historical database to provide big data support for the accurate decision-making of scientific grain storage. On this basis, a grain situation expert decision-making system should be gradually established. When the grain situation changes abnormally, the alarm sent by the system will be directly notified to the mobile phone of the responsible person, and according to the ecological digital model of grain storage in the region, after comprehensive analysis by the system, the handling opinions will be recommend. It is even directly associated with intelligent ventilation, fumigation and insecticide, modified atmosphere storage and other equipment, and corresponding measures will be taken automatically after authorization to truly realize the perfect integration of "measurement" and "control. The model of the integrated monitoring system of the grain depot is shown in the following figure:

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