JPS6135274Y2 - - Google Patents

Description

[Detailed explanation of the idea]

This invention relates to a device used to remove oxygen dissolved in various liquids. Here, "removal of dissolved oxygen" refers to a relative reduction in the oxygen content based on the ratio of the oxygen and nitrogen content in the liquid phase in the equilibrium state reached when the liquid surface is in contact with air. Refers to causing. In equilibrium with air, water at room temperature has a concentration of 10 to 15 ppm.
of nitrogen and 5 to 9 ppm of oxygen in solution, so that the oxygen to nitrogen ratio is about 1:3 to 1:1 by weight. According to this invention, the oxygen content can be reduced from 8 ppm to 0. The nitrogen may also be replaced by other inert gases such as helium, argon, neon, etc., or mixtures thereof. In many fields where water is used, it is desirable to obtain water with a low oxygen content, since oxygen dissolved in water has undesirable effects. For example, in the case of boiler water, dissolved oxygen promotes corrosion of the boiler inner wall surface, so hydrazine,
Deoxygenation is performed by adding NaSO ₃ or the like to perform a reduction treatment. In addition, in the case of liquid foods such as juice and milk, in order to prevent accelerated spoilage due to dissolved oxygen, treatments such as deoxygenation by heating, low temperature sterilization, carbonation, or addition of preservatives are essential. In the case of brewed products such as sake or grape wine, some deoxidation occurs through fermentation, but the effect is small and preservatives must be added for long-term storage. That is, even in the case of food, if sufficient deoxidation is performed or deoxygenated water can be used, it is possible to safely store the food for a long period of time without the need to add foreign substances. The purpose of this invention is to provide an effective and economical device for removing oxygen dissolved in liquids. In the device of this invention, dissolved oxygen is basically removed by contacting the liquid to be treated with a high-purity inert gas such as high-purity nitrogen gas. This is done by substituting. Next, an embodiment of this invention will be described with reference to the drawings. Reference numeral 1 in the figure indicates a cylindrical airtight bubbler arranged so that its axis is vertical.
A liquid to be treated, that is, a liquid from which dissolved oxygen is to be removed (hereinafter referred to as "raw water") is introduced into the bubbler 1 from a pipe 2 at its lower end. Further, a pipe 3 that opens at the upper end of the bubbler 1 communicates with the upper end of a settler 4 made of an airtight cylindrical body, so that the raw water introduced from the pipe 2 to the bottom of the bubbler 1 is After ascending in 1, it flows into settler 4 through pipe 3. A pipe 5 extends downward from the upper end of the bubbler 1, and air bubbles are fed into the raw water in the bubbler 1 from the tip of the pipe 5. As will be described in detail later, the gas sent from the pipe 5 contains a high concentration of nitrogen and almost no oxygen, so the raw water in the bubbler 1 is
It rises in the bubbler 1 while coming into contact with this nitrogen-containing gas, and in this process, dissolved oxygen is replaced with nitrogen gas. The raw water that has passed from the bubbler 1 through the pipe 3 into the settler 4 has already had dissolved oxygen removed to a high degree. When the water is taken out after passing through the process, it becomes hypoxic water with extremely low oxygen content. Note that the height of the upper end of the pipe 6 determines the height of the liquid level in the settler 4. On the other hand, the gas separated from the raw water in the bubbler 1 is led to the upper end of the settler 4 through the pipe 7, and is taken out through the pipe 8 together with the gas separated from the raw water in the settler 4, and is then purified to high purity. of hydrogen gas, and then introduced into a reactor 9 filled with a hydrogenation catalyst. The amount of hydrogen gas to be added is determined by measuring the oxygen content of the gas flowing in the pipe 8 using an oxygen meter 10, and calculating the value necessary for reacting with this oxygen to produce water. It is calculated stoichiometrically and minutely adjusted to maintain this value strictly. Therefore, in the reactor 9, oxygen and hydrogen in the gas react in just the right amount to generate water, and this reaction product is introduced into the condenser 12 via the pipe 11. An oxygen meter 13 is provided in the pipe 11 in order to check whether the gas discharged from the reactor 9 still contains free oxygen. The condenser 12 is connected to the reactor 9 via the pipe 11.
The condensed water is separated by a trap 14 and then sent to a drain sump 16 via a pipe 15.
The remaining gas is recirculated as high purity nitrogen gas into the bubbler 1 via a pipe 5 with a pump 17. Therefore, this high purity nitrogen gas contains substantially no oxygen or hydrogen. In addition, a pipe 18, a pump 19, and an oxygen meter 20 are provided to monitor the oxygen content in the treated water, and a pipe 21 and a container 22 are provided to adjust the pressure in the settler 4. Replenishment takes place through a pipe 24 with a valve 23. The efficiency of removing oxygen by the hydrogenation reaction in the reactor 9 depends on the amount of hydrogen added to the oxygen content in the gas entering the reactor 9 with the same catalyst.
If this amount of hydrogen addition is increased, bubbler 5
The oxygen concentration in the high-purity nitrogen gas supplied to the reactor decreases, and therefore the dissolved oxygen concentration in the treated water also decreases, but if the amount of hydrogen added becomes excessive, hydrogen accumulates in the gas. While making sure that the hydrogen content in the treated water is below the detection limit, using the dissolved oxygen removal device shown in the figure, raw water inflow rate: 2.22/min Dissolved oxygen concentration: 7.96ppm Water temperature: 27℃ Gas circulation amount: 10 An experiment was conducted to determine the changes in the oxygen concentration in the gas and the dissolved oxygen concentration in the treated water when only the amount of hydrogen added was changed under the condition of 1/min. The experimental results are shown in Table 1 below.

[Table] From the above results, the final dissolved oxygen concentration is
66ppb, and the amount of hydrogen added at this time was 32.6cc/
It turns out that it is a minute. Furthermore, if two dissolved oxygen removal devices with similar configurations are arranged in series in terms of water flow, and the treated water obtained by one device is used as raw water and the same treatment is performed in the other device, the dissolved oxygen It is possible to reduce the concentration to below the detection limit (in one step).
7.8ppm→50ppb, 2-stage 50ppb→0). This means that the dissolved oxygen removal effect obtained when the flow system device that does not use hydrogen, which was previously invented by the present inventors, is installed vertically in four or more stages, can be achieved in one stage, and it can be achieved in 10 stages. The above shows that the present invention can achieve performance below the detection limit, which is impossible to achieve, with a two-stage device.Also, compared to the previous invention, which used hydrogen, the present invention almost completely eliminates nitrogen. This shows the superiority of a closed system device. As explained above, this invention achieves a high degree of dissolved oxygen removal without using chemicals such as reducing agents, and can be applied to a wide range of fields, especially since it can be reduced to below the detection limit with as many as two stages. It is particularly useful in the production of food and medicine. Furthermore, since this can be done without mechanically stirring the liquid, it is highly economical in terms of power.

[Brief explanation of the drawing]

The drawing is a system diagram showing the configuration of a dissolved oxygen removal device according to an embodiment of this invention. 1...Bubbler, 3...Pipe, 4...Settler, 9...Reactor, 12...Condenser, 14...
...Trap.

Claims (1)

[Claims for Utility Model Registration] (1) An airtight bubbler having a means for blowing high-purity inert gas into the raw water contained therein and having an intake port for introducing the raw water, and an airtight settler for storing the treated raw water; a means for extracting treated water with a low oxygen content from the settler; and an oxygen meter for measuring the amount of oxygen contained in the gas extracted from the settler;
means for adding to the gas taken out from the settler an amount of ultra-high purity hydrogen that is necessary and not excessive to react with the amount of oxygen measured by the oxygen meter to produce water; a reactor for producing water by reacting oxygen and hydrogen contained in the reactor; a means for removing water from the gas exiting the reactor; Dissolved oxygen removal apparatus comprising means for recycling as a pure inert gas and means for transferring gas within said bubbler into said settler. (2) Utility model registration claim No. 1 in which two dissolved oxygen removal devices are provided, and the treated water taken out from the settler of one dissolved oxygen removal device is supplied as raw water to the other dissolved oxygen removal device.
Dissolved oxygen removal device as described in section.