Comparison Of The Application Effect Of Two Kinds Of Stored Grain Mildew Monitoring Methods

This report mainly studies the monitoring technology of pest-free biological activity in storage grain,compares the application effect and characteristics of CO2 gas monitoring method and grain reactor temperature monitoring method in the monitoring of insect pest activity,and analyzes the conditions of grain temperature,moisture,biological hazards and other conditions on CO2 gas monitoring.The influence of temperature monitoring of the grain heap provides technical support for safeguarding grain storage security.The law of heat conduction in grain reactors was studied.A constant temperature point was set as a heat source at a depth of 60 cm in the grain piles.Temperature points were set at equal distances in both the horizontal and vertical directions to monitor the variation of grain temperature.The results showed that the distance from the heat source was 10 At the cm site,a significant increase in grain temperature was detected after 2 days,while significant changes were observed at 30 cm and 50 cm after 4 and 6 days,respectively.Grain temperature conduction has a significant attenuation effect with increasing distance.On the 4th day of the experiment,the monitored grain temperature at 10 cm,30 cm and 50 cm from the heat source increased by 5.2 ℃ ± 0.5 ℃ and 1.3 ℃ ± 0.5 ℃,respectively.And 0.2 ℃ ± 0.5 ℃;On the 10 th day of the experiment,the temperature of the monitored grain from the 50 cm height increased by only 2.6 ℃ ± 0.5 ℃.When the monitoring point departs from the heat source level,the monitored temperature change will be significantly reduced,and the temperature of the middle layer of the heat source layer and the 10 th d below the 50 cm from the heat source layer is increased by 7.4 ℃ and 0.9 ℃,respectively.The characteristics of carbon dioxide gas diffusion in large grain piles have been studied.The results show that the diffusion of gases in grain piles is affected by many factors.The temperature rises from 20 ℃ to 30 ℃.The carbon dioxide gas concentration at 50 cm and the ratio at the mildew point increase from 0.36 to 0.63.The carbon dioxide gas diffusion ability at high temperature is strong;when the gas origin concentration increases from 0 to ≥ 5%,the diffusivity of carbon dioxide gas at 50 cm and 100 cm from the horizontal direction increased by 3.0 times and 2.0 times respectively,and the higher concentration of carbon dioxide gas was more conducive to diffusion in grain piles.The CO2 gas monitoring and grain temperature monitoring in the grain piles were compared under different ambient temperature conditions(20 ℃,25 ℃,and 30 ℃).The results showed that there were similar gas production rates and heat production rates at the mildew point,and their detection values.Can accurately measure the growth of mold.When the monitoring point deviates from the mildew origin,the influence of the outside temperature on the mildew point cannot be displayed in the temperature monitoring point,but the effect on the monitoring value of the CO2 gas is very obvious,and the deviation from the mildew origin at temperatures of 20 ℃,25 ℃ and 30 ℃.A significant change in CO2 concentration can be monitored on the 2nd day of the 50 cm horizontal monitoring point,and its concentration values are 0.07%,0.32%,and 0.45%,respectively.The amount of moldy grain in the grain pile has a great influence on CO2 gas monitoring and temperature monitoring.The results showed that 30 kg of mildewed grain was buried in the grain piles.The farthest detection distances on the 10 th day were 20 cm in temperature and 50 cm CO2 gas.The farthest detection distances of temperature and CO2 gas in the 15 kg mildewed grain were 10 cm and 30 cm.It shows that there is a good corresponding relationship between the scale of moldy grain in the grain pile and effective monitoring distance,and the sensitivity of CO2 gas monitoring is higher.In order to study the effect of mildew rate on the two monitoring methods,the changes of CO2 gas and temperature in grain reactors were monitored by adjusting the grain moisture,changing the growth rate of moulds.The results showed that the maximum concentration of CO2 gas produced in 10 days at the origin was 0.18% when simulated package moisture was 17.6%,and CO2 gas concentration of 21.2% moisture was significantly increased,17.6% and 21.2 within 10 days.The CO2 gas concentration monitored at the mildew of the mildew grain mildew at the origin of the moisture increased by 168.4% and 103.5%,respectively;while the temperature at the mildew at the mildew grain of 17.6% and 21.2% moisture was increased by 1.4%.45.5%.When the mildew grain moisture content is low,the CO2 gas monitoring method can monitor the mild changes in CO2 gas concentration produced by mildew,and the grain temperature detector’s monitoring accuracy is low,and it can not accurately reflect mildew.The site of mildew in the grain pile has a significant effect on CO2 gas monitoring and temperature monitoring.The test results show that the maximum monitoring distance in the horizontal direction of the mold-deposited area with 100 cm depth is 50 cm for grain temperature monitoring method and 200 cm for CO2 gas monitoring method;the detectable distance for 50 cm depth is only 30 cm and 100 cm,respectively.The deeper the location of the moldy point is,the greater the detectable distance of the CO2 gas and temperature at the moldy point of the mold.CO2 gas detection method is more sensitive to the detection of deep mildew.Through the comparison of the two kinds of monitoring methods under various conditions,it can be concluded that the CO2 gas detection method can reflect the safe situation of grain storage in time and accurately.CO2 gas detection can be more sensitive and more accurate to monitor the activities of the mold.