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, intelligent control and precise management of grain depots are the key to achieve safe and efficient grain storage.
The most important thing in grain storage is insecticidal treatment. Aluminum phosphide is a very effective insecticide for grain storage, which is widely used in grain storage in China. It can be deliquescent when water or moisture is absorbed. It emits a highly toxic phosphine gas. The grain depot laboratory technician will be exposed to phosphine gas when taking samples and testing temperature, humidity and inspecting grain condition and insect condition, as well as when the storekeeper enters the depot to measure temperature, humidity and insect condition. Some of them are phosphine poisoning due to lack of safety and hygiene knowledge.
In order to investigate the concentration of phosphine in grain warehouse during fumigation and the time when the concentration of phosphine in grain warehouse falls below the national health standard after fumigation, it is necessary to monitor the concentration change of phosphine in grain warehouse after fumigation and the ambient concentration of gases such as O 2 and CO 2. To provide scientific basis for the protection of human health. During the fumigation period, the phosphine concentration in silos and grain piles was very high, peaking at 48 hours and 96 hours, and much higher than that in grain piles in the first two days. However, with the passage of time, the difference between the two becomes smaller and tends to be balanced, which indicates that the hydrogen phosphide produced by aluminium phosphide after deliquescence quickly diffuses in the silo and gradually permeates into the grain heap. The concentration of hydrogen phosphide in the silo decreases to near the national health standard two days after opening and venting. After the second closure, the phosphine concentration in the grain stack decreases gradually, while that in the grain stack increases first and then decreases. This indicates that the phosphine in the grain stack gradually releases into the space of the grain stack after the second closure, which causes the increase of the phosphine concentration in the grain stack. It was not until the 9th day that the concentration of phosphine in grain piles and warehouses fell below the national hygienic standards. It is safer to enter the warehouse about half a month after fumigation.
On the basis of the existing digital temperature measurement, the grain condition monitoring and early warning module of the warehousing business management system should also integrate the functions of automatic analysis of the gas, humidity and insect pests in the grain stack, and the measured data should be written into the historical database to provide large data support for the accurate decision-making of scientific grain storage. On this basis, an expert decision-making system for grain condition should be established step by step. 。 When abnormal changes occur in the grain situation, the alarm sent by the system directly notifies the responsible mobile phone, and according to the ecological digital model of grain storage in this area, after comprehensive analysis of the system, recommend treatment suggestions; even directly related to intelligent ventilation, fumigation, insecticide, controlled atmosphere storage and other equipment, automatically take phase after authorization. Measures should be taken to achieve the perfect integration of "measurement" and "control". The following figure shows the model of grain depot comprehensive monitoring system:
Alphasense, a two-year conventional electrochemical principle phosphine sensor, is our company's agent, specializing in monitoring and alarming the concentration of phosphine in granaries or industries. It has good stability, high sensitivity, fast response and high cost performance. It also has 10 ppm small range PH3-A1/B1 and 2000 ppm large range PH3-BE optional.
The main performance parameters are as follows:
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