JPH0780205A - Selective deaeration and its device - Google Patents

Abstract

PURPOSE:To provide a deaeration method for removing selectively only a dissolved gas of such a type as not required from a liquid containing a few different types of dissolved gas at low initial and running costs and under a simple constitution as well as a device using this method. CONSTITUTION:A liquid to be treated is allowed to pass through one side of a gas permeable membrane, while another type of gas than the type to be removed is allowed to pass through the other side of the membrane. Thus a dissolved gas is removed as a selective deaeration method. As a selective deaeration device embodying this method, a a feeder line 12 of a liquid to be treated is connected to one end of a deaeration module 10 equipped with a gas permeable membrane 11, and a discharge line 13 is connected to the other end. Further, one side of the gas permeable membrane 11 is a liquid phase side for the introduction of a liquid to be treated, and the other side is a gas phase side for the introduction of a gas. A gas feeder line 14 for feeding a gas of any other type than the type to be removed is connected to the gas phase side of the gas permeable membrane 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to liquids such as effervescent alcoholic beverages and carbonated beverages which require deoxidation treatment for maintaining quality, and pharmaceuticals, cosmetics, etc.
The present invention relates to a degassing method for selectively removing only a desired type of gas from a liquid or the like that requires removal of bubbles, and an apparatus therefor.

[0002]

2. Description of the Related Art As is well known, dissolved oxygen in a liquid is considered to be a factor of oxidation, and when the liquid itself is a product,
It causes the deterioration of the components in the liquid and oxidizes the object to be cleaned when it is used for cleaning or the like. For example, in alcoholic beverages such as sake, wine, shochu, soft drinks, fruit juice drinks, etc., deterioration of flavor due to the influence of oxygen dissolved in the drink,
Discoloration occurs.

Therefore, in order to remove dissolved oxygen from the liquid and prevent such a phenomenon, various methods such as aeration method (gas replacement method), heating deaeration method, vacuum deaeration method, and chemical method are used. Degassing methods have been proposed. In the aeration method (gas replacement method), a high-purity gas other than oxygen (for example, nitrogen gas, carbon dioxide gas) is blown into the liquid in the tank, the high-purity gas and the liquid are brought into direct contact, and the oxygen partial pressure in the liquid is adjusted. By lowering
Physically removes dissolved oxygen. In the thermal degassing method, the liquid is heated by an appropriate means to release and remove the dissolved gas. The vacuum degassing method is a method of degassing a dissolved gas in a liquid by reducing the gas partial pressure by making a contact atmosphere with the liquid into a vacuum by using a degassing tower. In recent years, as one of the vacuum degassing methods, a gas permeable membrane (hydrophobic polymer membrane) that allows only gas to pass through without passing water is used, through which dissolved oxygen in water is transferred to the gas phase under reduced pressure. A film-type vacuum degassing method for precipitation is also in practical use.
The chemical deaeration method uses a chemical such as an oxygen scavenger.

However, in the case of a liquid such as beer, sparkling wine, or other low-malt beer or carbonated beverages in which a specific gas (carbon dioxide gas in this case) needs to be dissolved,
In the vacuum deaeration method and the heat deaeration method as described above, not only dissolved oxygen but also carbon dioxide gas, which is an important element of the flavor as a product of this kind, is removed. Therefore, it becomes necessary to re-add carbon dioxide gas later, but the cost of carbon dioxide gas for this re-addition is very high. In addition to the above-mentioned problems, in the heating degassing method, oxygen is redissolved due to careless operation and equipment malfunction because degassing is performed in an open system, and in addition to the above-mentioned problems Is not applicable. Further, the chemical deaeration method uses a chemical such as an oxygen scavenger, so that the flavor is impaired and there is a problem in safety. Therefore, in such a type of liquid, carbon dioxide was used as the high-purity gas to deoxidize it by the aeration method.

[0005]

When removing dissolved oxygen from a liquid containing a specific gas (carbon dioxide gas) such as Happoshu or carbonated drink as described above, it is performed by aeration using carbon dioxide gas. However, in order to reduce the dissolved oxygen concentration in the liquid to a low level, it is necessary to use extremely high purity carbon dioxide gas, and also to reduce the size of bubbles of carbon dioxide gas blown into the liquid and It is necessary to take measures such as increasing the contact area with the gas, and it takes a lot of time. Specifically, it is difficult to reduce the amount of dissolved oxygen to 1 ppm or less even when aerating beer with carbon dioxide in a tank for 40 minutes. Further, aeration is performed under a positive pressure due to the restriction of the apparatus configuration, but it is difficult to remove dissolved oxygen if the atmospheric pressure is high.

Further, since this aeration method is performed in a batch system, a large amount of gas to be aerated is required, and
Since a large amount of bubbles are generated by aeration and the effective volume of the tank becomes small, a large-scale aeration tank is required. Furthermore,
When carbon dioxide aerating beer etc. in such an aeration tank,
Since bubbles of beer flow in and out from the air vent at the top of the aeration tank, there is a possibility of bacterial contamination from the outside, which is not good for hygiene. The present invention solves the above-mentioned problems of the membrane-type deaerator, has a low-cost and simple apparatus configuration, and removes a necessary kind of gas from a plurality of kinds of dissolved gas contained in a liquid product. Instead, the purpose is to remove only a predetermined type of gas.

[0007]

The present invention has been made in view of the above-mentioned problems, and combines the membrane degassing method and the gas replacement method without using a vacuum suction means or a large-capacity aeration tank. The target dissolved gas is removed by utilizing the difference in partial pressure between both sides of the gas permeable membrane.

Specifically, in selectively removing only the target type of dissolved gas from a liquid product containing a plurality of types of dissolved gas, the liquid product is circulated to one side of the gas permeable membrane, It is a selective degassing method characterized in that a gas of a type other than the one to be removed is circulated to the other side to remove the target dissolved gas, and one end of a degassing module equipped with a gas permeable membrane. A liquid supply side to which the liquid to be treated is introduced, and a discharge line to the other end is connected to each other, one side of the gas permeable membrane is a liquid phase side for introducing the liquid to be treated, and the other side is a gas phase side for introducing the gas. The selective degassing apparatus is characterized in that a gas supply line for supplying a gas of a type other than the gas to be removed is connected to the gas phase side of the gas permeable membrane.

[0009]

According to the present invention, the liquid in which a plurality of types of gases are dissolved and the type of gas other than the one to be removed are brought into contact with each other through the gas permeable membrane to separate the gas phase side from the liquid phase side. Due to the pressure difference, only the target dissolved gas is selectively removed.

[0010]

EXAMPLES Examples of the method of the present invention will be described below. First, for a liquid to be selectively degassed, a gas (referred to as gas A) that needs to remain in the liquid and a gas to be removed (referred to as gas X) are determined. Then, the liquid to be treated is circulated on one side of the gas permeable membrane (hereinafter, this side is referred to as a liquid phase side), and the same type as the gas A which needs to remain on the other side is determined in the preceding paragraph. The gas A is circulated (hereinafter, this side is referred to as the gas phase side). Then, the gases A and X are the gas A on the liquid phase side and the gas A on the gas phase side.
And the partial pressure of the gas X are equal to each other so that they move between the gas phase side and the liquid phase side.

Since only the gas A is supplied to the gas phase side, the partial pressure of the gas X is 0 at the initial stage. Therefore, the gas X is the gas A from the liquid phase side to the gas phase side.
Moves from the gas phase side to the liquid phase side through the gas permeable membrane, so that the partial pressure of the gas A on the liquid phase side increases, but the partial pressure of the gas X decreases, and as a result, the gas from the liquid to be treated becomes gas. X is removed. At this time, by supplying only the gas A to the gas phase side and keeping the partial pressure of the gas X as zero as possible, the gas X on the liquid phase side
Can be removed until it is substantially zero.

In the above description, only one kind of gas that needs to remain is dissolved in the specific treatment liquid. However, when there are two or more kinds of gas that need to remain, the partial pressure The ratio is measured or determined in advance, and the gas mixed with this partial pressure ratio is supplied to the gas phase side. By doing this, of the dissolved gas in the liquid to be treated on the liquid phase side,
Only gases other than mixed gas supplied to the gas phase side can be removed, and the partial pressure ratio of the dissolved gas in the liquid after the treatment is substantially the same as the partial pressure ratio of the mixed gas supplied to the gas phase side. Will be equal. Therefore, by predetermining the partial pressure ratio or composition of the mixed gas supplied to the gas phase side, the partial pressure ratio of the dissolved gas in the treatment liquid can be adjusted. Further, in the present invention, since the partial pressure difference is utilized during degassing as described above, it is desirable that the gas supplied to the gas phase side be supplied in a pressurized state. In this case, it is the object in the liquid to be treated. While the dissolved gas is removed more effectively, it is possible to effectively prevent the reduction of the dissolved amount of the gas that does not need to be removed.

Next, an example of an apparatus to which the method of the present invention is applied will be described with reference to FIG. In the drawing, a degassing module (10) contains a gas permeable membrane (11) in the form of a hollow fiber or a flat membrane, and the inside of the degassing module (10) is accommodated by this gas permeable membrane (11). The space is divided into a liquid phase side through which the liquid to be treated flows and a gas phase side through which a gas flows.

A supply line (13) for the liquid to be treated is connected to one end of the degassing module (10) on the liquid phase side, and a discharge line (14) for the treatment liquid is connected to the other end thereof. A gas supply line (14) is connected to one end and an exhaust line (15) is connected to the other end.

The gas supply line (14) is, as described above,
For supplying a single type of gas that needs to remain in the liquid to be treated, or a mixed gas having a predetermined composition ratio,
The gas A is contained in a cylinder (17) connected upstream of the gas supply line (14). A pressure adjusting valve (16) is interposed between the cylinder (17) and the degassing module (10) to adjust the supply pressure to the gas phase side in the degassing module (10).

A flow meter is provided in the middle of one exhaust line (15).
(18) and the flow rate adjusting valve (19) are connected, and the degassing module can also be used by this flow meter (18) and the flow rate adjusting valve (19).
The supply pressure to the gas phase side in (10) can be adjusted.

In the above structure, it is necessary to supply the liquid to be treated from the supply line (13) to the liquid phase side in the degassing module (10) and to leave it in the liquid to be treated from the gas supply line (14). A certain kind of gas or a mixed gas of a plurality of kinds is adjusted to a predetermined pressure and flow rate by the pressure adjusting valve (16) and the flow rate adjusting valve (19) and supplied. Then, as described above, due to the difference in the partial pressure ratios of the gas in the gas phase section and the liquid phase section in the degassing module (10), the gas X existing only in the liquid to be treated is present.
Moves from the liquid phase side to the gas phase side through the gas permeable membrane (11), the supply gas A moves to the liquid phase side, and as a result, the gas X is removed from the liquid to be treated. Then, the supply gas A on the gas phase side is discharged out of the system through the exhaust line (15) while containing the gas X.

By further providing a gas separating device on the downstream side of the exhaust line (15), the supply gas A and the gas X can be separated and reused respectively. For example, when the supply gas A is carbon dioxide gas and the gas X is oxygen, the two can be easily separated by using a condenser.

A more specific application example of the above selective degassing method and apparatus will be described below. First, a case where the above-mentioned beer is applied will be described. As is well known, beer is a beer stock solution immediately after fermentation, oxygen is consumed by yeast, and dissolved oxygen is not substantially contained, but in the subsequent filtration step, by inclusion of air, etc., Oxygen is dissolved in. Therefore, it is provided between this step of beer and the filling step of filling the container.

The filtered beer is supplied to the degassing module (10) from the specific treatment liquid supply line (13) of the degassing device, and is a main element of the flavor of beer from the gas supply line (14). When carbon dioxide gas is supplied, only dissolved oxygen is selectively removed from beer as described above, and it is not necessary to re-add carbon dioxide gas later as in the conventional case. Therefore, the degassed beer can be prevented from deteriorating the flavor due to dissolved oxygen in the subsequent steps and in the distribution process after shipment from the factory.

The amount of carbon dioxide gas consumed in this degassing process is larger than that in the conventional degassing oxygen method by carbon dioxide gas aeration.
Very small amount. Furthermore, in the conventional deoxidation method by aeration, a large-scale aeration tank facility is required, and deoxidation treatment can be performed only in a batch system, but according to the present invention, such a simple small facility as described above is used. Thus, continuous deoxidation treatment can be performed. Actually, when comparing the conventional aeration method and the deaeration method according to the present invention with respect to the consumption amount of carbon dioxide when deoxidizing beer to the same degree, it is 350 liters per a kiloliter of beer by the aeration method. According to the present invention, the consumption is about 36 to 44 liters, about 1/8 to 1 /
It has been drastically reduced to about 10 consumption.

In the case of this deoxidation treatment, some carbon dioxide gas is added to the beer on the liquid phase side.
It is necessary for beer, and it can be a beer with a good foam.

Next, in the case of applying to sake, nitrogen gas containing alcohol (as vapor) is circulated to the gas phase side of the gas permeable membrane (10) so that the dissolved oxygen can be removed without the scattering of alcohol. Can be removed. In addition, at this time, if a gas containing a fragrance component such as ginjo fragrance (generally higher alcohols and higher esters) that is desired to avoid being scattered from sake in nitrogen gas is flowed, such a fragrance component is not scattered. , Deoxidation treatment can be performed.

Next, in the case of applying it to a biological experiment, for example, a culture solution of bacteria or the like or a breeding water of goldfish or the like, while flowing oxygen to the gas phase side of the gas permeable membrane (10), the liquid phase By flowing a liquid containing carbon dioxide (or water) to the side, only carbon dioxide can be selectively removed without removing dissolved oxygen. In this case, if the composition of the gas flowing to the gas phase side (for example, the ratio of oxygen, nitrogen gas, etc. and carbon dioxide gas) is adjusted, the proportion of decarbonated gas in the treatment liquid can be adjusted, so that the predetermined BOD can be obtained.
(Biochemical Oxgen Demand) value or COD (Chemic Demand)
Al Oxgen Demand) value of the culture solution and breeding water can be obtained.

In addition to the above application examples, other sparkling wines, liquors such as shochu, other beverages, liquid seasonings such as soy sauce, liquid products such as cosmetic liquids, and raw material liquids thereof It can be easily applied even in the production line for concentrated stock solutions, split water, etc.

[0026]

According to the present invention, by bringing a liquid in which a plurality of types of gases are dissolved and a type of gas other than those to be removed into contact with each other through a gas permeable membrane, only the target dissolved gas can be obtained. Can be selectively removed,
In the past, selective degassing of various liquids, which had only been done by aeration, could be performed easily with a small device with a simple structure.
And it can be done continuously.

Further, according to the conventional aeration method, a large amount of high-purity gas (or gas having a predetermined composition) is consumed, but according to the present invention, the consumption can be greatly reduced. Further, by using the gas permeable membrane, the contact area between the liquid phase portion and the gas phase portion can be increased as compared with the aeration method, so that the degassing efficiency is high.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of an apparatus according to the present invention.

[Explanation of symbols]

 (10) Degassing module (11) Gas permeable membrane (12) Treated liquid supply line (13) Treated water discharge line (14) Gas supply line (15) Exhaust line

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location C12C 11/00 C12G 1/06 3/02 119 S

Claims (2)

[Claims] 1. A degassing method for selectively removing only a target type of dissolved gas from a liquid in which a plurality of types of gases are dissolved, wherein a liquid to be treated is circulated on one side of a gas permeable membrane. A selective degassing method, characterized in that the target dissolved gas is removed by circulating a gas of a type other than that to be removed to the other side. 2. A degassing device for selectively removing only a target type of dissolved gas from a liquid in which a plurality of types of gas are dissolved, the degassing module (10) having a gas permeable membrane (11). A liquid supply side (12) for the liquid to be treated is connected to one end and a discharge line (13) is connected to the other end, and one side of the gas permeable membrane (11) is connected to the liquid phase side for introducing the liquid to be treated, the other side. The side of is the gas phase side for introducing the gas, and to the gas phase side of the gas permeable membrane (11), a gas supply line (14) for supplying a gas of a type other than the gas to be removed is connected. A selective degassing device characterized by the above.