JPS6050517B2 - Water reforming method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for modifying water that prevents corrosion of metals constituting pipes and equipment through which water flows, and also prevents scale from depositing or adhering to the surfaces thereof.

City water, groundwater, river water, and various process waters are themselves corrosive to metals, but the oxygen contained in these waters also oxidizes and corrodes metals.

In addition, hardness components in water such as silica, iron, and zinc deposit and adhere to metal surfaces as scales, clogging piping systems and reducing the heat exchange coefficient of boilers, heat exchangers, etc. This also makes it difficult to transport water. In other words, tanks, boilers, condensers, evaporators, cooling towers, and other related equipment, equipment, and piping connected to water supply, hot water supply, and cooling water system piping may be corroded by contact with water, or scale may accumulate. This can cause adhesion, which can impede heat exchange and reduce its efficiency, and can cause wear and tear on these equipment.

As a result, these facilities must be taken out of service and repaired or replaced with new ones. Nowadays, when resource saving, labor saving, and energy saving are emphasized, it is urgently desired to establish measures to solve these problems. Conventionally, corrosion inhibitors such as chromate-based, polymerized phosphate-based, zinc compound-based, and silicate-based agents have been used to prevent corrosion caused by water, but those with strong anti-corrosion effects are highly toxic. There are many disadvantages, such as the wastewater after treatment does not meet the wastewater regulation standards, causing problems of environmental pollution, and relatively non-hazardous corrosion inhibitors have little corrosion-preventing effect.

The purpose of the present invention is that the water obtained when drinking water is treated meets the water quality standards of the Water Supply Law as drinking water, and that the water obtained from other treated water passes the wastewater standards based on the Water Pollution Control Law.
The purpose of the present invention is to provide a water reforming method that does not corrode equipment or cause rust.

Another object of the invention is to heat, pressurize, transport,) cool,
It is an object of the present invention to provide a water reforming method that reduces the amount of scale generated when performing treatments such as distillation.

Still another object of the present invention is to provide a method for modifying water that softens water and prevents discoloration and coloring.

As a result of intensive research to achieve these objectives, the present inventors obtained the following knowledge and were able to complete the present invention.

(1) Corrosion and rust that occur inside piping and equipment that circulate water are greatly influenced by the amount of air mixed and dissolved in the water.

(2) When water is heated, pumped, or rained down from a cooling tower, causing turbulent movement, air gets mixed in and dissolves.

This air is largely separated by reducing the velocity of the turbulence and making it laminar. (3) When phytic acid or its salt is added and dissolved in water, even if dissolved oxygen remains in the water, corrosion of piping and equipment that comes into contact with it is prevented.
It chelates active metal ions dissolved in water and renders them inactive, making it effective as a softening agent.

Phytic acid or its salts are contained in rice, wheat, soybeans, onion corn, etc. In Japan, it is an industrial chemical extracted from rice bran, and is harmless to the human body and does not cause environmental pollution problems.

(4) When a combination of air-water separation treatment that turns turbulent water into a laminar flow and separates and removes the air contained in the water, and a treatment that adds and dissolves phytic acid or its salts to this water, It was found that both treatments complement each other and provide a corrosion-preventing effect that is far superior to that obtained when each treatment is used alone.

The gist of the present invention, which was achieved based on these findings, is to introduce a water flow into an air-water separator, maintain a laminar flow, separate and remove air contained in the water, and remove 1000 ppm or less of phytic acid or its salt. This is a method for modifying water by adding and dissolving it in this water.

The water pumped is pulsating and creating a turbulent flow.

In order to make this water flow a laminar flow, it is achieved by setting the flow rate to approximately 0.3 mIsec or less, although there are some differences depending on the speed of this turbulent flow and the liquid temperature. This embodiment will be explained with reference to FIG. 1, which is an explanatory diagram of a steam/water separator.

Water sent by the pump 6 flows into the steam/water separator 1 through the supply ports 4 and is decelerated to form a laminar flow.

At this time, the air mixed in the water is separated in a very short time, collected in the air chamber 2, and exhausted from the air vent valve 3, and the water containing a small amount of dissolved air is discharged from the drain port 5. The diameter and length of the steam/water separator are appropriately determined according to the amount and flow rate of water to be supplied so that laminar flow occurs within the device.

The air chamber 2 can also be under reduced pressure to facilitate removal of separated air.

Although it is inevitable that a small amount of dissolved air remains in the water discharged from the air-water separator, metals can be dissolved by adding and dissolving an appropriate amount of phytic acid or its salt, as shown in the examples later. Corrosion is prevented.

Phytic acid or its salts are also effective as water softeners. When compared with polyphosphoric acid, which has been conventionally used as a softening agent, excellent results were obtained as shown below.
Table 1 shows the results of a water softening experiment in which fixed amounts of polyphosphoric acid and sodium phytate were added to water with a hardness component of 100 ppm (as CaCO3).

Phytic acid or its salt may be added before or after the steam/water separation step, and can be freely determined depending on the case. The amount of phytic acid or its salt added varies depending on the process, type of water, hardness, etc., but generally 1.
Concentrations from 0 to 1000 ppm are used.

When water is reformed according to the present invention, if the water being sent comes into contact with the atmosphere and receives sufficient turbulence, the amount of dissolved oxygen in the water will reach the saturation value at that temperature, but the amount of dissolved oxygen in the water will reach the saturation value at that temperature. By passing through the separation device, most of the air mixed in the water is removed, and by adding and dissolving phytic acid or its salt before or after this air-water separation process, air-water separation can be achieved. It was possible to achieve effects that could not be achieved by a single step of treatment alone or addition and dissolution of phytic acid or its salt. In other words, it has a greater effect on preventing corrosion and scale precipitation than conventional anti-corrosion agents and anti-corrosion methods for metals in equipment through which water flows, does not cause discoloration or staining of water, and reduces the amount of phytic acid or its salt used. It is economical as it has a small amount of water, and there is no fear of pollution caused by wastewater.

Examples will be shown below to make the present invention easier to understand, but the present invention is not limited to these.

Example 1 An example of the present invention was shown using a device incorporating a cooling tower, a steam/water separator, and a tank shown in FIG.

S. The corrosion rate, water softening, scale generation status 1, etc. were observed and measured using S-41W4 (2 x 20 x 80) TWL test pieces to show the differences from the comparative example. Total hardness: 69p
pm (as CaCO3) flows into the cooling tower 8, is allowed to rain, is sent to the air-water separator 1, where air is separated as a laminar flow, and then flows into the tank 9 through a pipe equipped with a softening agent inlet 7. The mixture was then circulated within the apparatus using pump 6 for 47 days.

The water lost was replenished externally, ensuring that a constant amount of water was constantly being circulated. Valves 10 and 11 are opened and closed to allow bypass of the steam/water separator 1 for testing purposes. The test piece was suspended in water in tank 9. Tests were conducted using the method of the present invention and three comparative examples as shown below.

(1) Valve 10 was closed and valve 11 was opened to circulate the raw water without passing it through the air-water separator.

(Comparative Example 1) (2) While the raw water was circulated through the air-water separator in the same manner as above, sodium phytate was introduced from the softener inlet 7 so that the concentration in the raw water was 1000 ppm. (Comparative Example 2) (3) Valve 10 was opened and valve 11 was closed, and the raw water was circulated through the air-water separator.

(Comparative Example 3) (4) As in (3) above, while the raw water was circulated through the steam-water separator, sodium phytate was introduced from the softener inlet to a concentration of 500 ppm. (
Method of the present invention) The results are shown in Table 2. As is clear from the table, (1) raw water that has passed through the steam/water separator has a reduced dissolved oxygen and metal corrosion rate, but no scale prevention effect is observed.

(Example (3)) (2) If you want to add and dissolve sodium phytate, the corrosion rate of the metal and the total hardness of the water are O regardless of whether it passes through a steam/water separator, and the scale prevention effect is also large. be.

(Examples (2), (4)) (3) When the water is passed through a steam-water separator, the amount of sodium befitate input is halved compared to when it is not passed through, which has a large economic effect. (Examples (2), (4)) Example 2 The same tap water as in Example 1 and 50 ppm of sodium phytate were added to a water heater equipped with a steam-water separator, and the tap water dissolved therein was heated for 30 days. I made a comparison.

(1) Corrosion rate of raw water: 1.48 mg no D77 f' no D
ay. , total hardness of water; 69 ppm (as CaCO3)
, scale prevention effect; not observed.

(2) Corrosion rate for the one containing sodium phytate: 0.34m91ddIday. , the total hardness of water: 32 ppm (as CaCO3), and the scale prevention effect: large results were obtained, and it was recognized that the addition and dissolution of sodium phytate had a large effect.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a steam/water separator, and FIG. 2 is an explanatory diagram of a device incorporating the cooling tower, the steam/water separator, and the futank shown in Example 1. 1... Air-water separator main body, 2... Air chamber, 6... Pump, 7... Softener inlet, 8... Cooling tower, 9...
·tank.

Claims (1)

[Claims] 1 A water stream characterized by introducing a water stream into an air-water separator, maintaining a laminar flow, separating and removing air contained in the water, and adding and dissolving 1000 ppm or less of phytic acid or its salt into the water. Modification method.