JP2001048528A - Production of dried seawater product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a dried seawater product, by which the dried product achieving the reduction of transportation cost, the improvement of stability with the passage of time, the improvement of handleability and the decrease in microorganism contamination can be obtained at a low cost, by concentrating seawater by a reverse osmotic membrane treatment and then wholly drying the concentrated seawater to give a specific particle diameter and a specific dry weight loss. SOLUTION: This method for producing a dried seawater product comprises treating seawater collected from an inland sea or an open sea and not contaminated with industrial liquid wastes by the use of a reverse osmotic membrane to concentrate the seawater into a concentration of preferably about 1.3 to 2.5 times. Examples of the usable reverse osmotic membrane includes the asymmetric membranes, complicated membranes, and so on, produced from cellulose acetate, polyamides, and the like. The obtained concentrated sea water is wholly dried. The drying is carried out by a drying method such as a heating method, a lyophilizing method or a vacuum drying method, especially a method for using a spray-drier. Thereby, the dried seawater product preferably having a particle diameter of 0.5 to 1,000 μm and a dried weight loss of 3 to 20% and richly containing minerals can be obtained at a low cost.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention achieves a reduction in transportation costs, an improvement in stability over time, an improvement in handling properties, and a reduction in microbial contamination obtained by subjecting seawater to reverse osmosis membrane treatment and then drying. It relates to dried seawater.

[0002]

2. Description of the Related Art Conventionally, inorganic industrial products such as salt and magnesium chloride have been produced from seawater. Purity of the products has been remarkably improved with recent technological advances. Further, particularly recently, as a result of research on minerals in a living body, it has been pointed out that many trace minerals are very important in a living body. In response to this, many industries tend to place importance on trace minerals, and seawater is attracting attention as a mineral source, and many products using seawater as they are have been put on the market.

[0003]

However, in order to use seawater as it is, transportation costs, deterioration of components due to aging, particularly microbial contamination or propagation during transportation become a problem. Currently, only seawater can be used as it is. Also, heat seawater as it is,
If drying is performed by a known drying method before the present application such as freeze drying and reduced pressure drying, the solid content in seawater is only about 3%. The accompanying process is very costly and has little economic merit. Further, it is known before the present application to electrodialyze seawater to effectively extract solute components.However, according to this method, there are many elements that are difficult to pass through a dialysis membrane among active ingredients and contained in seawater. Of trace minerals cannot be used effectively.

[0004]

Means for Solving the Problems In the present invention, as a result of intensive research in view of the present situation, seawater is subjected to reverse osmosis membrane treatment,
It has been found that by drying completely, a seawater dried product rich in minerals, free from microorganisms and stable in quality can be obtained, and the present invention has been completed. The seawater in the present invention may be collected in any of the waters near Japan or the open sea, but there is no pollution such as factory drainage,
It is necessary to collect seawater with less variation in components depending on the sampling lot. The concentration of the reverse osmosis membrane treated water used for drying is desirably 1.3 to 2.5 times the concentration of seawater. At this time, in order to dry the concentrated seawater, a known drying method such as heating, freeze drying, and drying under reduced pressure is sufficient, and a spray dryer is preferable. The dried seawater obtained by the present invention contains magnesium chloride, calcium sulfate, potassium chloride and the like in addition to sodium chloride as a main component, and the particle size thereof is preferably 1 to 1000 μm, and 1 μm.
If it is less than 100 μm, it will consolidate. If it is more than 1000 μm, it will take a long time to dissolve. Loss on drying of dried seawater is 1g
Is preferably 3 to 20% by weight under the condition of drying at 105 ° C for 5 hours. If the loss on drying is less than 3% by weight, the cost for drying increases, and if it is more than 20% by weight, halophiles grow.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The seawater dried product of the present invention is a mineral-rich product which is highly stable with time and free of microbial contamination in all fields such as food, inorganic and organic industrial materials, animal feed, etc., where mineral supplementation is studied. There is a feature.
First, seawater collected from an inland or open sea is subjected to reverse osmosis membrane treatment to separate it into water and concentrated water. The reverse osmosis membrane used at this time may be any of an asymmetric membrane or a composite membrane of cellulose acetate type, polyamide type or the like. In the present invention, the concentration of the reverse osmosis membrane-treated water obtained by the reverse osmosis membrane treatment is about 1.1 to 2.5 times. It is good, but in practice, the seawater to be subjected to the drying step is suitably one obtained by concentrating seawater 1.3 to 2.5 times. In addition, in order to dry the concentrated seawater, a known drying method such as heating, freeze drying, and drying under reduced pressure is sufficient, and a spray dryer is preferable.

In the present invention, the dried seawater finally obtained by the reverse osmosis membrane step and the drying step mainly contains sodium chloride, magnesium chloride, calcium sulfate, potassium chloride and the like. Is 1 to
1000 μm is preferable, and if it is less than 1 μm,
If it is larger than 00 μm, it takes a long time for dissolution. In the present invention, the collected seawater is subjected to reverse osmosis membrane treatment using a reverse osmosis membrane such as a cellulose acetate-based or polyamide-based asymmetric membrane or a composite membrane to separate water and concentrated water. At this time, the concentration of the reverse osmosis membrane treatment water obtained by the reverse osmosis membrane treatment is about 1.1 to 2.5 times, and the water is further concentrated by a well-known drying method such as heating, freeze drying, and vacuum drying. The present invention will be described in more detail with reference to the following examples, which are dried to form a dried seawater. However, the configuration of the present invention is not limited to these examples.

[0007]

Example 1 Reverse osmosis membrane treated seawater was separated into water and concentrated water using a reverse osmosis membrane. The reverse osmosis membrane separation device was manufactured by Toray Industries, Inc., and the seawater was concentrated up to twice. The composition of seawater used for separation and treated concentrated seawater was as shown in Table 1.

[0008]

[Table 1]

[0009]

Example 2 Production of Dried Seawater The concentrated seawater having a double concentration obtained by the reverse osmosis membrane treatment in Example 1 was dried using a spray drier.
A seawater dried product was obtained. Table 2 shows the analysis values of the dried seawater.

[0010]

[Table 2]

[0011]

[Test Example 1] 500 g (water content: 18%) of dried seawater having different average particle diameters were packed in an aluminum pack, and allowed to stand in a constant temperature and humidity chamber at 40 ° C and a relative humidity of 75% for one month. A closing test was performed. Table 3 shows the results.

[0012]

[Table 3]

[0013]

Test Example 2 300 g (water content: 18%) of dried seawater having different average particle diameters were added to 1 L of water, and the mixture was stirred and dissolved (300 rpm) with a lab stirrer, and the time required for dissolution was measured. Table 4 shows the results.

[0014]

[Table 4]

[0015]

Test Example 3 10 g of dried seawater having a reduced weight in Table 5 was left open for one week in a low-humidity environment, and then 1 g was taken.
The sample solution dissolved in 0 ml and diluted appropriately was smeared and cultured on a plate agar medium, and the number of viable cells was counted.

[0016]

[Table 5]

According to the results of the above test examples, the seawater dried product obtained by the present invention had consolidation at a particle size of 0.3 μm, and no consolidation was observed at 1 μm. Also, looking at the obtained seawater dried product dissolution time, it was confirmed that the dissolution time was long when the particle size was 2000 μm or more. Furthermore, it was also found that when the loss on drying is 30% or more, the number of viable bacteria greatly increases due to the propagation of halophilic bacteria.

[0018]

EFFECTS OF THE INVENTION The dried seawater produced from the seawater of the present invention can be produced at low cost, is rich in minerals, is free of microorganisms, has high stability over time, and has high handling properties. It can provide dried seawater and has a great social contribution.

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Claims (3)

[Claims] 1. A seawater dried product, wherein seawater is subjected to a reverse osmosis membrane treatment and completely dried. 2. The dried seawater product according to claim 1, wherein the particle size is 0.5 to 1000 μm. 3. The dried seawater product according to claim 2, wherein the loss on drying is 3% to 20%.