The Influence Of Temperature And Humidity On The Condensation Of Rice In The Container And The Evaluation Of The Anti-condensation Effect Of The Dehumidification Bag

With the improvement of grain transportation modernization,bulk packaging,bulk transportation,bulk unloading and bulk storage are constantly improving.Container transportation has the features of safe,fast and economical,so containers have become another way of bulk grain transportation.Dew condensation refers to the phenomenon that water vapor in the air reaches saturation and condenses into liquid water.Temperature when condensation occurs referred to as the dew point.Condensation is directly related to the changes of air humidity and temperature.The main cause of grain condensation is the temperature difference between the grain pile and the outside world.At present,the domestic research on the problem of food condensation mainly focuses on the grain silo,while the research on the problem of container condensation is relatively few.When rice is stored and transported in a container,it is easy to be affected by the external environmental conditions.In this experiment,for the analysis of the temperature and humidity effects on rice grain heap of condensation in the container and the container desiccant bag for preventing rice grain piles to evaluate the effect of condensation,the newly harvested colored rice is poured into a container,and the container is placed in an artificial climate room for simulation of the environmental conditions when the container is transported.To control the temperature and humidity inside and outside the container,respectively at low temperature and low humidity(15?,50%),low temperature and medium humidity(15?,60%),low temperature and high humidity(15?,70%),medium temperature and low humidity(25?,50%),Medium temperature and medium humidity(25?,60%),medium temperature and high humidity(25?,70%),high temperature and low humidity(35?,50%),high temperature and medium humidity(35?,60%),high temperature and high humidity(35?,70%).The rice grain temperature,dew point temperature,condensation temperature and relative humidity of the different partitions and stratification were tested.Use the method of hanging dehumidification bags in the columns fixed at the corners of the container to absorb part of the moisture in the air and reduce the relative humidity in the container,thereby preventing the occurrence of condensation.By measuring and calculating the dew point temperature,moisture content,grain temperature and other indicators,a mathematical model is established according to the relationship between them,to provide an early warning method for accurately judging the dew condensation in the grain pile in the container.The dehumidification effects of different locations and different contents are compared to provide early warning and provide theoretical basis and technical support for the condensation of rice grain piles in the container.The results show that:1.The critical period of preventing condensation is the early stage of container transportation.The area 5-30cm below the grain surface should be inspected.2.When the moisture content of the rice grain stack in the container is 10%-11%,12%-13%,14%-15%and 16%-17%respectively,the dew point of the rice grain is different under different temperature and humidity.3.Through the analysis of dew-point temperature,grain temperature and water content of the rice grain stack in the container,the mathematical model of dew-point temperature,grain temperature and water content is obtained.The dew-point temperature can be calculated according to the following formula:Dew point temperature=grain temperature+2W-34.17(W<14%)or dew point temperature=grain temperature+W-20.13(W?14%).4.Through the measurement of the actual water vapor and relative humidity in the container,it can be seen that the effect of using dehumidification bags in the northeast corner,southeast corner,northwest corner and southwest corner of the container is the same.Considering the cost saving and economy of transportation,it is recommended to use 3 dehumidification bags under this experimental condition,namely,the dehumidification bag specification is 36.7 g/m~3.In practice,the container volume of 20 GP is 33.1 m~3,so the dosage of dehumidificati is 1215 g.Conclusion:The main reason of leading to grain condensation is the difference of temperature.Temperature and humidity is the important factors causing grain condensation.From the mathematical model of dew point temperature,temperature and humidity is an important factor affecting dew.Temperature and humidity are important factors that affect condensation.The greater the relative humidity in the environment,the smaller the temperature difference of condensation and it is easier to condense.In addition,the early stage of container transportation is the key period for preventing condensation.The effective dosage and dehumidification effect of calcium chloride water absorption dehumidification bag were obtained by detecting the anticondensation effect index.