JPH06254540A - Production of pure water - Google Patents

Abstract

PURPOSE:To produce high-purity pure water with inexpensive equipment by successively laminating and freezing raw water while imparting refrigerating load on the rear surface side of a supporting body consisting of a good heat conductor and while allowing the raw water to flow down along the surface of this supporting body, then melting the obtained transparent ice. CONSTITUTION:The raw water 5 flows down on a stainless belt 1 while its width is regulated by a waterproof dike when the raw water 5 is sprinkled onto the front surface side of the belt 1 by sprinkling pipe 4. A plate cooler 3 in which brine 19 cooled to about -12 deg.C is circulated by an evaporator 21 of a heat pump cycle is pressed to the rear surface of the belt 1 and, therefore, the raw water 5 is frozen at the time of dropping on the belt 1. The freezing is thereafter repeated while the flowing down raw water 5 is successively laminated. A planar body 5A having the thickness increasing nearer the bottom end is produced. This planar body 5A is peeled at the bottom end of the belt 1 and is separated from the water in a water/ice separating section 7; thereafter, the planar body is melted in a heating and melting layer B, by which the pure water is taken out.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pure water production method which effectively combines freezing / melting of water.

[0002]

2. Description of the Related Art Conventionally, pure water has been produced by coagulating sedimentation treatment,
After producing primary pure water by ion exchange resin treatment of cations, anions, etc., reverse osmosis membrane treatment, etc., it is further subjected to treatments such as microfiltration and ultraviolet irradiation according to the purpose, and can be suitably used as semiconductor washing water, for example. Secondary pure water (highly pure water)
Are manufactured.

[0003]

However, the above-mentioned conventional treatment system is capable of coagulating and precipitating treatment, ion-exchange resin treatment, reverse osmosis membrane treatment and target impurities to be removed, even when producing primary pure water. As a result, a badge recycling system by a recycling process is required, which requires several processing steps, resulting in a complicated process and an increase in size of processing equipment. Further, for example, fine particles and organic substances in water are adsorbed in the ion exchange resin tank, but since the ion exchange resin deteriorates due to use, it is necessary to appropriately regenerate it. In general, the regenerating treatment is a neutralizing agent. However, since the neutralizing agent is a powerful drug, it is troublesome to dispose of the neutralizing agent after the regeneration treatment.

In view of such prior art, the present invention is capable of removing fine particles and organic substances in water even without using the above-mentioned ion exchange resin tank, and further it is difficult to remove the colloidal silica or other colloidal particles. An object of the present invention is to provide a method for producing pure water that can effectively remove even metal components. Another object of the present invention is to provide a pure water production method capable of obtaining primary pure water in a single treatment step without combining a plurality of different treatment steps such as coagulation sedimentation, filtration and adsorption. To aim.

[0005]

The process leading to the present invention will be described step by step. When the present inventor performs freezing in an ice making box that is commercially or industrially used, as the transparent ice successively freezes on the inner wall of the ice making box, the raw water of the unfrozen portion in the center (core water It has been found that dissolved gas and impurities such as chlorine, air, and dust in the raw water are concentrated on the () side.

[0006] Generally, the core water is dehydrated during ice making, raw water is poured, and the stirring means is stopped.
Although transparent ice is manufactured, the water quality of the cross-sectional layer portion (see FIG. 3) from the outside to the central layer of the ice thus manufactured is analyzed and the result is as shown in FIG. (: Transparent ice part of the outer layer ,: white ice part in the center,
: Raw water)

As can be seen from this table, the transparent ice portion outside the ice box sufficiently satisfies the standard conformity values for pure water with respect to electrical conductivity and silica, and metal ions and anions also have raw water. It can be understood that all of them are reduced to 1 PPM or less, and the requirements for pure water are sufficiently satisfied. Therefore, it can be understood that pure water or highly pure water similar to this can be obtained by freezing tap water and remelting the transparent ice portion obtained by the freezing.

However, it is quite difficult to take out only clear ice from the ice obtained by the commercial or industrial ice making method. Ice making ice box is thick and has a long freezing time and is not economical. Moreover, in order to produce high-quality transparent ice by the ice box method, the slow freezing method must be adopted, and as a result, the ice making time becomes significantly long. Therefore, the present inventor studied a method of once freezing the raw water or the pretreated water and remelting the ice obtained by the freezing to obtain pure water or highly pure water close to this, and finally That was the completion.

That is, the present invention was manufactured by applying a refrigerating load to the back side of a support made of a good heat conductor while successively flowing raw water or pretreated water along the surface of the support to successively freeze the layers. In the method of producing pure water by melting transparent ice. In this case, the transparent ice support is preferably composed of an endless belt made of a good heat conductor which is tilted at a predetermined angle along the belt transport direction and has a refrigeration load applied to its back side. In the pure water production process, there are two heat cycles of freezing the raw water and heating the transparent ice to remove heat and to apply heat. Therefore, an evaporation heat source is used to cool the refrigeration load, while a heat is used to melt the transparent ice. The heat balance becomes extremely good by using the heat pump cycle that uses the respective condensation heat sources. Further, the present invention is to improve the efficiency and reduce the cost of pure water by using the evaporation heat source for cooling the refrigerating load and using it for other cooling purposes for melting the transparent ice.

[0010]

According to the present invention, for example, ice is sequentially laminated on a support to be frozen by letting fresh water flow down on the support made of a good heat conductor and having a refrigeration load applied to the back side. Since the formed ice surface has a structure in which fresh water always flows down, as a result, continuous slow freezing at 0 ° C. is possible. Moreover, since it is plate-shaped ice, it is thin and quick to freeze, so it is efficient. Also, since the plate-like ice surface is coated with fresh water while flowing down, there is no fear of impurities adhering during the freezing, and high-purity transparent ice can be produced. And since all the ice produced by the above method is transparent ice,
By melting this as it is, primary pure water can be easily produced. Further, the ice making process is continuous, and de-icing does not require heat means such as other defrosting. The raw water used in the present invention does not require pretreatment, tap water can be used as it is, and it is economical because a single treatment step is sufficient. Further, since no filter or the like is used, there is no need to regenerate it, facilitating maintenance and greatly reducing maintenance costs.

[0011]

Embodiments of the present invention will now be illustratively described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative positions and the like of the components described in this embodiment are not intended to limit the scope of the present invention thereto, but are merely examples, unless otherwise specified. Not too much. Figure 1
2 shows a primary pure water producing apparatus according to an embodiment of the present invention. The present system comprises a continuous ice making machine A for producing transparent ice from raw water, a heating and melting tank B for melting the transparent ice produced by the ice making machine, and a heat pump cycle C for supplying heat to these (heat removal). Consists of.

First, the continuous ice making machine A will be described. Reference numeral 1 denotes an endless stainless belt that is slightly inclined downward in the conveying direction, and is continuously or intermittently driven by an upper rotor 2 and a lower rotor 2 '. Further, the inclination angle α of the belt 1 is set to such an extent that transparent ice can be produced by slow freezing.
It is preferable to determine the conditions under which the transparent ice can be produced most efficiently by the three factors of the cooling temperature from the plate cooler 3 and the flow rate of the raw water caused by the inclination. The stainless belt 1
As shown in FIG. 2, rubber belt-like water leakage prevention ridges 17 are provided on both sides of the upper surface of the belt 1 so that the raw water does not leak to the left and right while the raw water flows down. Also, the bank 18 is the belt 1.
It is a rubber belt that drives the stainless belt 1 by providing it on both sides of the lower surface.
The leakage from the side of the belt 1 of the brine passing through the gap between the plate cooler 3 and the plate cooler 3
By forming the ring-shaped recessed groove 18A into which the prevention bank 18 is fitted in the lower rotor 2 ', the prevention bank 18 also functions as a guide strip, and allows the belt 1 to smoothly circulate.

Reference numeral 3 denotes a plate cooler slidably brought into contact with the back surface (lower surface) of the belt 1 in the forward direction (upper side), and the heat exchanger 2 functioning as an evaporator of a heat pump cycle.
1, the brine 19 cooled to around -12 ° C is circulated. Further, 3 may be the direct expansion of the refrigerant. Further, the stainless belt 1 itself and the plate cooler 3 are in contact with each other while circling, so that the stainless belt 1 does not necessarily contact evenly over the entire surface, and a gap is generated to greatly improve heat transfer efficiency. It may decrease. Therefore, in the present embodiment, a part of the brine 19 is diverted, or another brine 19 such as ethylene glycol is flowed from an independent circuit into the gap from the upper end of the plate cooler 3 attachment position using the injection nozzle 23. It is preferable to improve the heat transfer efficiency between the stainless belt 1 and the plate cooler 3 and level the thermal contact by transferring heat through the brine 19 through the brine 19.

Reference numeral 4 denotes a raw water spray pipe arranged at an upper position on the upper end side of the belt 1, and a pipe body having a large number of downward jet nozzles 6 attached thereto extends over the entire width of the belt 1 for ice / water separation. Bowl 7
The cold water in the water tank 11 is supplied by precooling the raw water via the heat exchanger 15, and the precooled raw water 5 is averaged over the entire width of the belt 1 from the spray pipe 4 to the upper surface of the belt 1. It is constructed so that it can be sprayed with water and is circulated by a pump. In particular, by precooling the raw water by passing the brine 19 through the heat exchanger 15, the temperature difference required for cooling is reduced, and slower freezing is facilitated. Reference numeral 7 denotes an ice / water separator disposed at a lower position on the lower end side of the belt 1, which comprises a water storage tank 11 having a mesh plate 8 provided on the upper surface thereof, and the mesh plate 8 is inclined slightly downward toward the transport conveyor 10 side. At the same time, the lower end of the tilt is connected to the guide plate 8A,
The transparent ice 12 from which water has been separated along A is configured so as to be thrown into the heating and melting tank B via the conveyor 10.

The inner wall surface of the heating and melting tank B is coated with Teflon, and a stainless steel heating pipe 31 is spirally surrounded along the inner circumference of the inner wall surface. The heating load fluid in the heating pipe 31 is
The pump 3 while heating to around 10 to 20 ° C. by the heat exchanger 32 that functions as the condenser of the heat pump cycle C.
It is configured to be able to circulate by 3. The heating pipe 31 may also be used as the condenser 32. As is well known, the heat pump cycle C comprises a compressor 41, a condenser 32, a liquid receiver 42, an expansion valve 43, and an evaporator 21, and a refrigerant circulates in the cycle C to repeat heat evaporation while repeating evaporation, compression and condensation. Exchange.

Next, the operation of this embodiment will be described. Sprinkler pipe 4
When tap water, pretreatment water, or other raw water 5 is sprinkled on the upper surface of the stainless belt 1, the belt 1 is installed at an appropriate inclination angle. While flowing, it flows down on the belt 1. On the other hand, since the plate cooler 3 is in contact with the lower surface of the belt 1, the raw water 5 freezes while flowing down on the belt 1, and the raw water 5 that flows down afterwards is repeatedly laminated and freezes repeatedly. It is possible to manufacture the plate-shaped ice 5A that becomes thicker toward the lower end side of 1. At this time, the raw water 5 flowing down on the upper surface of the belt 1 flows to about 0 ° C. to −3 ° C. due to the cold heat from the plate cooler 3 and flows to form thin ice on the plate cooler, and the raw water 5 is formed thereon. It does not become a quick freezing by flowing down, but is slowly frozen at -5 to 8 ° C, that is, a transparent plate-like ice with high purity while eliminating contamination of the raw water 5 with the above-mentioned air, nitrogen, carbon dioxide and the like. 5A can be manufactured.

Although the freezing is slow freezing, it does not freeze the thick raw water 5 all at once as in an ice making box, but it freezes a thin layer of raw water 5 that is repeatedly flown down. The time is much shorter, and high ice-making efficiency can be obtained. Further, in order to produce highly pure clear ice with higher accuracy, it is most efficient to use the following three factors: the spray amount of the raw water 5, the cooling temperature from the plate cooler 3 and the flow rate of the raw water 5 due to the inclination. It is recommended to find the conditions under which clear ice can be produced.

Further, since the surface of the plate-shaped ice 5A is coated with the raw water 5 while flowing down at all times, it is possible to produce high-quality, high-purity ice 5A without fear of impurities adhering during the freezing. Become. The plate-shaped ice 5A generated on the stainless belt 1 to have a predetermined thickness has a predetermined width by utilizing the bending force of the belt 1 when the lower rotor 2'circulates on the lower end side of the stainless belt 1. It is cracked and peeled off and falls on the mesh plate 8 below it. In the mesh plate 8 water and ice 5
After separating A, the conveyor 1 along the guide plate 8A
Then, the transparent ice is melted by pouring into the heating and melting tank through 0 to produce pure water. Then, when the water quality analysis was similarly performed on the pure water manufactured as described above, the water quality analysis values shown in the section of FIG.
With respect to silica, metal ions, and anions, high-quality pure water sufficiently satisfying the requirements as primary pure water was obtained.
Further, the heat of the ice used for melting the transparent ice is used for other cooling purposes, such as dehumidification, drying, cooling for air conditioning, etc., to further reduce the production cost of pure water. A steel belt whose surface is treated with a fluororesin may be used instead of the stainless belt.

[0019]

[Effects] As described above, according to the present invention, since pure water is produced by slowly freezing / melting raw water, it is difficult to remove fine particles and organic substances in water, and colloidal silica and the like which are conventionally difficult to remove. The colloidal metal component of can be effectively removed. According to the present invention, it is possible to obtain primary pure water in a single treatment step without combining a plurality of different treatment steps such as coagulation-sedimentation, filtration, and adsorption. Is greatly reduced. Also, since the freeze-thawing is performed using a heat pump cycle,
Effective use of heat energy can be achieved. It has various remarkable effects.

[Brief description of drawings]

FIG. 1 is an overall view showing a pure water production system according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a cross-sectional view showing a cross-section layer portion of ice manufactured by an ice box method.

FIG. 4 is a water quality analysis value for each of the present embodiment, the ice box method, and the raw water.

[Explanation of symbols]

 A transparent ice making device B heating and melting tank C heat pump cycle 1 stainless belt, 4 sprinkling pipe 5 raw water 3 plate cooler 7 water / ice separator 5A transparent ice

Claims (4)

[Claims] 1. Transparent ice produced by successively laminating and freezing ice while allowing raw water or pretreated water to flow down along the surface of the support while applying a refrigeration load to the back side of the support made of a good heat conductor. A method for producing pure water, which comprises melting and obtaining pure water. 2. The transparent ice support is an endless belt made of a good heat conductor which is inclined at a predetermined angle along the belt conveyance direction and has a refrigeration load applied to its back side. Pure water production method 3. The method for producing high-purity water according to claim 1, wherein a heat pump cycle using an evaporation heat source for cooling the refrigerating load and a condensation heat source for melting the transparent ice is used. 4. The method for producing high-purity water according to claim 1, wherein an evaporation heat source is used for cooling the refrigerating load, and another cooling purpose is used for melting the transparent ice.