JPH0141295B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Currently, food, feed, etc. are generally stored by separately drying them with hot air or the like and storing them in a storage warehouse such as a silo. Drying food, fodder, etc. with hot air or the like not only deteriorates the quality and taste, but is also economically disadvantageous and time-consuming. Furthermore, humid air may enter the storage room from outside during storage, and since the humidity inside the storage room is roughly the same as the outside air, it may be damaged by pests, rats, etc., and harmful substances such as mold may also enter the storage room. Occur.

In the present invention, food etc. are put into a storage in a raw state, dry gas is circulated through the storage instead of hot air, the gas humidity inside the storage is extremely low, and the food is naturally brought to room temperature or This is a method of drying at low temperatures.

In the solar drying method, the material is naturally dried in a humid atmosphere, and this is done due to the difference in humidity between the moisture of the material and the humidity of the atmosphere.

In the present invention, instead of humid air, dry gas is blown into the storage at room temperature or low temperature, and the exhaust gas that evaporates the moisture in the food is recycled as dry gas again in a separately provided gas drying device. use. In this case, since drying gas is used, there is a greater humidity difference between the material to be dried and the drying gas than in solar drying, and the drying speed is faster, which is approximately 10 times faster than solar drying. Furthermore, since dry gas at room temperature or low temperature is used without heating, the food does not deteriorate in quality. Furthermore, since the gas in the storage is dry gas, harmful animals, pests, fermentation bacteria, etc. are hardly generated in the storage. In addition, if the oxygen concentration in the gas in the storage is low or desired to be almost zero, an inert gas such as chloride gas is used. In this case, it is necessary to remove oxygen due to leakage from the outside and evaporated moisture from the stored material. A pair of adsorption towers containing carbon molecular sieves, silica gel, etc. that adsorb oxygen and moisture are installed externally, and the gas used is passed through these towers, where adsorption and desorption is performed to remove a portion of the oxygen and dry part of the oxygen. The gas is discharged from the top of the adsorption tower and recycled and reused as dry gas. Since the desorbed gas contains a large amount of oxygen and water, it is disposed of outside. If it is desired to replenish gas in an amount equivalent to this waste gas, replenishment is done by mixing external air into the circulating gas vented to the previous pair of adsorption towers. Next, the present invention will be explained in more detail with reference to the drawings.

After putting food etc. into the storage 1 through the input port 2 and sealing it, the blower 16 blows the food into the pipe 17.
Inert gas such as air or carbon dioxide gas is blown into the storage chamber. The discharged gas is vented through a pipe 4 to either one of the pair of adsorption towers A or A' through a valve 5 or 5'.

A and A' are switched by a timer, and when one is in the adsorption process by aerating gas, the other is in the depressurization desorption process by the vacuum pump 10.

For the purpose of removing moisture and oxygen from the gas, adsorbents capable of reversibly adsorbing and desorbing moisture and oxygen, such as carbon molecular sieves, are stored in the A and A' columns. Inside towers A and A',
In addition to the above adsorbents, other adsorbents such as silica gel, zeolite, and activated carbon may be accommodated in a layered form or in the form of a mixed layer with the above adsorbents. By passing the gas through the A and A' towers, a gas that is dried to a dew point of -75°C and contains substantially no moisture and only a small amount or substantially no oxygen is produced. can.

The gas blown into the lower part of the adsorption tower A absorbs moisture and oxygen in the tower and becomes dry gas through the valve 6 to the pipe 7, the blower 16, and the pipe 1.
7 and then circulated into the storage.

When an oxygen adsorbent is also enclosed in the adsorption tower A, the dry gas from which oxygen has been removed is discharged through the valve 6. Most of the oxygen can be removed to 0.1% or less, but the oxygen concentration can be controlled by changing the switching time of A and A'.

When the adsorption step is transferred to adsorption tower A', adsorption tower A enters the desorption step, valves 5 and 6 are closed, valve 9 is opened, and the pressure inside the tower is reduced by the vacuum pump 10. At this time, a small amount of dry gas enters from the adsorption tower A' through valve 8, and the adsorbed moisture and oxygen are completely desorbed. The desorbed gas passes through the tank 11, the pipe 12, and the valve 13, is mixed with the original gas from the pipe 4, and is vented into the adsorption tower A. The moisture concentration in the desorbed gas discharged through repeated adsorption and desorption in the adsorption towers A and A' gradually becomes thicker and begins to accumulate as a liquid in the tank 11, and the gas is completely separated into dry gas and liquid moisture. Evaporated water from stored food is stored in tank 1 as a liquid.
It is taken out within 1.

If an oxygen adsorbent is provided in the adsorption towers A and A', the desorbed gas will not be liquefied at atmospheric pressure even if the oxygen concentration becomes high, and will be discharged to the outside through the valve 14. Since the pressure inside the system will be reduced due to the release, if it is necessary to avoid this, please use valve 1.
5, the required amount of air is supplied from the outside.

By the above operation, drying gas is constantly fed into the storage 1, and the moisture in the dried material can be evaporated and dried.

When circulating a drying gas with a dew point of -75°C, the material to be dried can be dried to an absolutely dry state, but this is not necessary for foodstuffs, etc., and would actually impair their quality.
It is desirable to maintain a certain level of dryness. Therefore, put a hygrometer 18 of the material to be dried in the storage room,
When the humidity of the material to be dried reaches a certain level, the operation of the adsorption tower and the operation of the blower 16 are automatically stopped and left, and when the moisture content rises again for some reason, the adsorption tower is automatically stopped. And operation of the blower 16 can be started. In addition, in the case of operation using inert gas such as Chitsuso, the oxygen concentration in the dry gas is detected by the oxygen concentration meter 19, and the adsorption tower A,
By controlling the switching time of A′, the oxygen concentration in the drying gas can be kept constant.

Example The rice was dried using the method shown in the figure.

Rice 10Kg Initial moisture 24% Drying material 150m/mφ×1000m/mH Lower 100/min Air temperature 30℃ Adsorption tower 50m/mφ×300m/mH 2 towers Carbon molecular sieve 300
g/tower A, A' tower switching time 10 minutes As a result of operating for 12 hours under the above conditions, the moisture content of the rice was approximately 8%. Also, in tank 11 there are approximately
140g of water was collected. Further, the water content of the circulating drying gas had a dew point of about -70°C.

[Brief explanation of drawings]

The drawing is a flow sheet of a dry storage method for food, feed, etc. 1... Storage (double use as dryer), 2... Raw material input port, 3... Dry raw material outlet, 4... Wet gas outlet pipe, 5, 5'... Adsorption tower inlet gas valve, 6,
6'...Adsorption tower outlet dry gas valve, 7...Dry gas circulation pipe, 8...Adsorption tower return gas valve,
9,9'... Valve for depressurizing the adsorption tower, 10... Vacuum pump, 11... Condensed water tank, 12... Circulation gas pipe to the adsorption tower, 13... Circulation valve to the adsorption tower, 14... Gas discharge Valve, 15...Gas filling valve, 16...Blower, 17...Pipe, 1
8...Hygrometer, 19...Oxygen concentration meter, A, A'...
...Adsorption tower.

Claims (1)

[Scope of Claims] 1. Storing food, feed, etc. in a storage and sealing it; b. Blowing into the storage a gas at room temperature or low temperature that contains substantially no moisture and only a small amount or substantially of oxygen; (b) A step in which gas containing moisture and a small amount of oxygen that has evaporated from the storage is taken out from the storage; (c) The gas taken out from the storage is brought into contact with an adsorbent that can reversibly adsorb and desorb moisture and oxygen; A step of adsorbing and removing moisture and oxygen contained in the gas from the gas, and (d) circulating the gas obtained in the step (c), which contains substantially no moisture and only a small amount or substantially of oxygen, to a storage. The reverse adsorbent that has adsorbed moisture and oxygen in the step of b) is brought into contact with a portion of the gas that does not contain moisture and oxygen under a pressure lower than the pressure during adsorption to adsorb it. 1. A dry storage method for food, feed, etc., characterized by comprising a step of desorbing moisture and oxygen.