CN111149523A - Preservation method for corn stored in container - Google Patents

Preservation method for corn stored in container Download PDF

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Publication number
CN111149523A
CN111149523A CN201911393519.XA CN201911393519A CN111149523A CN 111149523 A CN111149523 A CN 111149523A CN 201911393519 A CN201911393519 A CN 201911393519A CN 111149523 A CN111149523 A CN 111149523A
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container
grain
corn
temperature difference
dew point
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迟晓星
肖宇洋
钱丽丽
左锋
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Heilongjiang Bayi Agricultural University
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Heilongjiang Bayi Agricultural University
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    • AHUMAN NECESSITIES
    • A01AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
    • A01FPROCESSING OF HARVESTED PRODUCE; HAY OR STRAW PRESSES; DEVICES FOR STORING AGRICULTURAL OR HORTICULTURAL PRODUCE
    • A01F25/00Storing agricultural or horticultural produce; Hanging-up harvested fruit
    • A01F25/14Containers specially adapted for storing
    • AHUMAN NECESSITIES
    • A01AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
    • A01FPROCESSING OF HARVESTED PRODUCE; HAY OR STRAW PRESSES; DEVICES FOR STORING AGRICULTURAL OR HORTICULTURAL PRODUCE
    • A01F25/00Storing agricultural or horticultural produce; Hanging-up harvested fruit

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  • Environmental Sciences (AREA)
  • Storage Of Fruits Or Vegetables (AREA)
  • Storage Of Harvested Produce (AREA)

Abstract

The invention discloses a method for storing corns in a container, which relates to the technical field of food packaging, and the method for storing corns in the container is characterized in that when the moisture percentage of a corn grain stack is 11.37-11.67%, the dew point temperature difference is 10.78-11.26 ℃; when the moisture percentage of the corn grain stack is 13.40-13.70%, the dew point temperature difference is 6.60-7.20 ℃; when the water content of the corn grain pile is 15.40-15.69%, the dew point temperature difference is 4.31-4.6 ℃. The dewing of the grain bulk usually occurs in the range of 50mm to 250mm below the grain surface. The test paper tests factors such as temperature and relative humidity of corn grains through experiments, analyzes an area in a container where the corn grain pile is easy to dewing, predicts the dewing temperature difference, performs dewing early warning, and provides a theoretical basis for grain storage safety.

Description

Preservation method for corn stored in container
The technical field is as follows:
the invention relates to the technical field of food packaging, in particular to a preservation method for storing corns in a container.
Background art:
corn is a main variety of food across-region circulation in China. The northeast and the northChina are the main corn producing areas in China. At present, domestic corn transportation mainly comprises wrapped grains and bulk grains, and in recent years, although container transportation is fast in development speed, the transportation capacity proportion is relatively low, the scale degree and the application range are limited, and the corn transportation is still subordinate. According to the data arrangement of the railway bureau and the port administration of each port in northeast province, the bulk grain, the wrapped grain and the container transportation proportion of the northeast China area with the most active container transportation are respectively changed from 49%, 36% and 15% in 2012 to 51%, 26% and 23% in 2013. The grain container transportation is also called grain container unitized transportation, and is bulk grain transportation in which grains are directly loaded into a container to realize grain position transfer. The grain container transportation test point in China starts from the middle and later periods of the last 90 years, and the grain container transportation scale is continuously improved along with the improvement of grain circulation marketization and the improvement of container transportation capacity and the maturity of ports and air routes. Compared with the transportation of wrapped grains and bulk grains, the corn container transportation has the following advantages: the circulation efficiency is improved, and the transportation time is shortened. Reduce logistics cost and the like. Although the corn container transportation has many advantages, the corn container transportation has some defects in the actual use process, so that the container transportation cannot completely replace the way of transporting the wrapped grains and the bulk grains in a short time.
After the grain is harvested, a grain storage ecosystem is formed with the environment during the storage period. Factors such as temperature, humidity, microorganisms and insect pests in the ecological system for storing grains can affect the stable storage of the grains. The dewing of the grain heap is one of the results shown after the stability of the grain storage ecosystem is destroyed. The dewing of the grain pile means that gaseous water contained in the air inside or outside the grain pile is condensed into liquid water and then attached to the surface layer or inside of the grain pile. The moisture condensation of the grain pile firstly causes the local moisture content of the grain pile to rise, thereby causing the grain particles to breathe vigorously, and the activities of microorganisms and storage pests are also intensified, at the moment, if the treatment is not proper, the grain pile is finally heated. The temperature difference is an important factor causing the condensation of the grain pile, the condensation is more serious when the temperature difference is larger, and the condensation phenomenon of the grain pile is frequent when seasons alternate by combining practical experience analysis. At present, domestic researches on the problem of grain condensation are mainly concentrated on grain bins, but the problems of container condensation are relatively few, so the experiment analyzes the region of the corn grain pile in the container where condensation is easy to occur, predicts the temperature difference of the condensation, performs condensation early warning and provides a theoretical basis for grain storage safety by testing factors such as corn grain temperature, relative humidity and the like.
The invention content is as follows:
the invention aims to overcome the defects of the prior art and provides a preservation method for storing corns in a container.
According to the preservation method for storing corns in the container, when the moisture percentage of the corn grain stack is 11.37% -11.67%, the dew point temperature difference is 10.78 ℃ -11.26 ℃; when the moisture percentage of the corn grain stack is 13.40-13.70%, the dew point temperature difference is 6.60-7.20 ℃; when the water content of the corn grain pile is 15.40-15.69%, the dew point temperature difference is 4.31-4.6 ℃. The dewing of the grain bulk usually occurs in the range of 50mm to 250mm below the grain surface.
As a further improvement of the invention, the container is used for storing and taking the container, and the size of the container is as follows: the length of the container is 1.51m, the width of the container is 0.61m, the height of the container is 0.65m, a fixing column is arranged in the container, a dehumidification bag is attached to the fixing column, and calcium chloride particles are filled in the dehumidification bag.
Corn (producing area: peony river;); a container (length 1.51m x width 0.61m x height 0.65 m); wet-dry bulb hygrothermograph: shanghai Tianrama instruments and meters, Inc.; electronic hygrothermograph: shenzhen Jintuojia electronic technology, Inc.; an alcohol thermometer: great wall electronic instrument.
The test paper tests factors such as temperature and relative humidity of corn grains through experiments, analyzes an area in a container where the corn grain pile is easy to dewing, predicts the dewing temperature difference, performs dewing early warning, and provides a theoretical basis for grain storage safety.
Description of the drawings:
FIG. 1 is a graph showing the changes of the temperature, the grain temperature and the relative humidity in the container;
FIG. 2 is a graph showing the variation of the temperature of grain at the upper, middle and lower layers of the container with the temperature inside the container;
FIG. 3 is a diagram showing the prediction of the dew point temperature difference of the corn grain pile in the container.
The specific implementation mode is as follows:
according to the preservation method for storing corns in the container, when the moisture percentage of the corn grain stack is 11.37% -11.67%, the dew point temperature difference is 10.78 ℃ -11.26 ℃; when the moisture percentage of the corn grain stack is 13.40-13.70%, the dew point temperature difference is 6.60-7.20 ℃; when the water content of the corn grain pile is 15.40-15.69%, the dew point temperature difference is 4.31-4.6 ℃. The dewing of the grain bulk usually occurs in the range of 50mm to 250mm below the grain surface.
The method uses a container to store and take the container, and the size of the container is as follows: the length of the container is 1.51m, the width of the container is 0.61m, the height of the container is 0.65m, a fixing column is arranged in the container, a dehumidification bag is attached to the fixing column, and calcium chloride particles are filled in the dehumidification bag.
The method of the invention is verified by the following experimental examples:
1. experimental methods
The northwest corner is the first point of the first zone, and the first layer is the upper layer. The distance between the first layer and the grain surface is 0.51m, the distance between the third layer and the bottom of the container is about 0.1m, the distance between the first point of the first layer and the inner wall of the container is 0.01m, the distance between the area and the interval is about 0.25m, the distance between the point and the point is about 0.59m, the first layer is divided into areas according to the up-down direction, the points are divided according to the north-south direction, and the total number of 3 areas is. Each temperature measuring line is provided with 4 temperature measuring sensors, and the temperature measuring lines are divided into areas in the up-down direction and are divided into points in the north-south direction.
The newly harvested corns are taken and poured into a container, the container is placed in an artificial climate chamber to simulate the environmental conditions during container transportation, and each index is measured periodically. The transportation period of the simulated container is 20 d.
2. Calculation of dew point
The dew point can be expressed by the following formula:
1) the saturated water vapor pressure above 0 ℃ should be calculated according to the following formula:
Es=Eo×10at/b+t
in the formula: es-the saturated water vapor pressure of air, in units of hectopascal (hPa);
E0-saturated water vapour pressure at an air temperature of 0 ℃, in hectopascal (hPa); e0=6.11hPa
t-air temperature, deg.C;
a-parameter, a ═ 7.5;
b-parameter, b 237.3
2) At a certain relative humidity Y, the water vapor pressure e of air can be calculated according to the following formula:
e=Y×Es
in the formula: e-the water vapor pressure of air, hPa;
y — relative humidity of air,%;
3) the dew point temperature of the air can be calculated according to the following formula:
td=b/[a/log(e/6.11)-1
in the formula: t is td-dew point temperature of air, ° c;
3. calculation of dew point temperature difference
20-W (W is more than or equal to 14 percent) or 34-2W (W is less than 14 percent)
In the formula: delta t-dew point temperature difference, DEG C; w-grain moisture percentage,%;
4. data processing
The data were processed and charted by Excel.
5. Analysis of results
(1) Temperature and humidity change rule of corn grain pile
As can be seen from fig. 1, the temperature in the container and the average grain temperature show a decreasing trend, and the relative humidity in the container is in the range of 60% -80%. From the data in fig. 1, it can be seen that the average grain temperature decreases at a much slower rate than the temperature in the container, which results in a certain temperature difference between the grain temperature and the temperature in the container, and the temperature difference provides possibility for the formation of dew condensation in the air in the container. The temperature difference is an important factor causing grain condensation, and the phenomenon of grain condensation is frequent when seasons alternate. If the temperature difference of adjacent areas is far larger than the critical value of the dewing temperature difference, the time for the dewing temperature difference to disappear is prolonged, the local moisture is increased in a large range, the dewing area is wider, the dewing degree is heavier, and the safe storage of grains is seriously damaged.
(2) Rule of corn grain layer temperature along with temperature change in container
From the analysis of the change of the temperature in the container shown in fig. 2, the temperature of the grain on the upper layer of the grain pile is most easily affected by the temperature in the container, and the temperature of the grain on the middle layer changesIn the second time of transformation, the temperature of the grains at the middle and lower layers changes less along with the temperature in the container. The condensation of the grain bulk usually occurs in the range of 50-250mm below the grain surface, viewed in the longitudinal direction. The grain temperature in northern areas of China is reduced to a lower level in winter, and the average grain temperature can be reduced to the range of-5 ℃ to 5 ℃. By the spring and summer, the whole grain pile can be regarded as a cold ice sucker, the ice sucker is taken out of the refrigerator, and dew is generated on the surface immediately. In grain dumps similar to a frozen stick, condensation on the surface is not as rapid and severe, but the formation of condensation water is essentially the same. In summer, the temperature of the bin rises along with the temperature rise, the temperature difference is formed between the bin temperature and the grain temperature, the lower the temperature of the grain pile, the larger the formed temperature difference is, the air in contact with the surface of the grain pile is influenced by a cold source of the grain pile, the temperature is reduced, the relative humidity rises until dew condensation occurs, and the moisture absorption and the moisture rise of the grains on the surface of the grain pile cause the phenomena of agglomeration and heating. If the granary is sealed, the temperature of the air in the granary rises, the humidity drops, and the granary becomes relatively dry, so that the surface of the grain pile in the state can not absorb moisture and can not dew, and the surface is dry heat at most, namely high-temperature grains. If the granary is not sealed, air outside the granary can be continuously exchanged with air inside the granary, air with high absolute humidity outside the granary is continuously cooled after entering the granary, the relative humidity is increased, moisture absorption on the grain surface is caused, dew is seriously formed on the surface of the grain pile until the moisture of the grain on the surface of the grain pile is continuously increased until the grain pile is caked and heated. Therefore, in the process of storing grains, the prevention work of dewing must be done[17]
(3) Prediction of corn grain pile dew point temperature difference
From FIG. 3, it can also be observed that the dew point temperature difference is 10.78 deg.C-11.26 deg.C when the moisture percentage of the corn grain stack is 11.37% -11.67%; when the moisture percentage of the corn grain stack is 13.40-13.70%, the dew point temperature difference is 6.60-7.20 ℃; when the water content of the corn grain pile is 15.40-15.69%, the dew point temperature difference is 4.31-4.6 ℃. The larger the difference between the internal and external temperatures, the more severe the condensation. The direct reason for the formation of dew in autumn and winter is also the temperature difference, but the air source generating dew is not the air entering the bin outside the bin but the air in the grain bulk. That is, as long as there is a sufficient temperature difference, regardless of the outside environment inside the entry binHow low the absolute humidity of the air is, condensation will occur as it is, because the condensation water does not come from the outside air entering the cabin. This is not the same source as summer dew. The higher the moisture content of the grain is, the higher the equilibrium humidity of the air in the grain stack is, the more easily the moisture condensation is caused, and the smaller the required temperature difference is, the more serious the moisture condensation is. This point is different from the condensation in summer, which is not much influenced by the moisture of grains[17]
6. Prevention measure for moisture condensation of corn in container
TABLE 1 Water vapor content in the Container
Figure BDA0002345654890000061
In order to prevent the dewing phenomenon of the corn in the container, a dehumidifying bag is hung in a post fixed at the corner of the container to absorb partial moisture in the air, so that the dew point temperature in the container is reduced, and the dewing is prevented. Our experimental results show that: the dehumidification bag can leak water after being used for 7 days as long as possible, and can leak water after being used for 4 days as short as possible. The maximum water absorption of the dehumidifying bag is 3.13g at the 1 st bag, and the water absorption of the dehumidifying bag is 1.73g at the least bag. Because the selected dehumidification bag contains calcium chloride and other particles and water absorption particles, the dehumidification bag is prevented from contacting the skin when in use; the dehumidification bag can not contact the corn grain pile when in use. When the dehumidification bag is used, a condensation preventive measure is taken on the surface of the corn grain pile, so that water leakage of the dehumidification bag or falling of particles such as calcium chloride and water absorption particles in the dehumidification bag into the corn grain pile in the process of using the dehumidification bag is prevented, and the corn cannot be eaten.

Claims (2)

1. The preservation method for storing the corns in the container is characterized in that: when the moisture percentage of the corn grain stack is 11.37-11.67%, the dew point temperature difference is 10.78-11.26 ℃; when the moisture percentage of the corn grain stack is 13.40-13.70%, the dew point temperature difference is 6.60-7.20 ℃; when the water content of the corn grain pile is 15.40-15.69%, the dew point temperature difference is 4.31-4.6 ℃. The dewing of the grain bulk usually occurs in the range of 50mm to 250mm below the grain surface.
2. The method of claim 1, wherein the corn is stored in a container, the container is taken, and the size of the container is: the length of the container is 1.51m, the width of the container is 0.61m, the height of the container is 0.65m, a fixing column is arranged in the container, a dehumidification bag is attached to the fixing column, and calcium chloride particles are filled in the dehumidification bag.
CN201911393519.XA 2019-12-30 2019-12-30 Preservation method for corn stored in container Pending CN111149523A (en)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104007776A (en) * 2014-05-23 2014-08-27 国家粮食局科学研究院 Grain pile dewing early-warning, prevention and control system and method based on temperature field and humidity field coupling
CN105416840A (en) * 2014-09-17 2016-03-23 蔡晓霞 Moistureproof dehumidifying bag
CN109060873A (en) * 2018-03-16 2018-12-21 河南工业大学 A kind of grain matter heat transmitting and condense parameter detection device and method
CN110286144A (en) * 2019-07-12 2019-09-27 吉林大学 A kind of grain heap moisture condensation prediction technique

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104007776A (en) * 2014-05-23 2014-08-27 国家粮食局科学研究院 Grain pile dewing early-warning, prevention and control system and method based on temperature field and humidity field coupling
CN105416840A (en) * 2014-09-17 2016-03-23 蔡晓霞 Moistureproof dehumidifying bag
CN109060873A (en) * 2018-03-16 2018-12-21 河南工业大学 A kind of grain matter heat transmitting and condense parameter detection device and method
CN110286144A (en) * 2019-07-12 2019-09-27 吉林大学 A kind of grain heap moisture condensation prediction technique

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Application publication date: 20200515