JPH03207421A - Nitrogen concentrator and method for concentrating nitrogen in containers - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a nitrogen concentrator for obtaining nitrogen-concentrated gas from air using the gas separation membrane of the present invention, and a method for concentrating nitrogen in a container using the same.

BACKGROUND OF THE INVENTION Nitrogen has been used as an inert gas in fields such as the chemical industry and the food storage electronics industry. Liquid nitrogen or a high-pressure nitrogen cylinder is generally used as a supply source for this nitrogen. However, these methods involve the risk of handling low-temperature liquid nitrogen and high-pressure cylinders, and have the problem of being complicated to handle, such as replacing containers, adjusting flow rates, and adjusting concentrations.

For this reason, attempts have been made to use a nitrogen-enriched gas obtained by removing oxygen from the air using a gas separation membrane as a nitrogen supply source for the above-mentioned purpose.

For example, what is shown in Japanese Patent Application Laid-Open No. 64-63020,
Alternatively, there are those shown in Japanese Patent Application Laid-open No. 60-231-406.

Problems to be Solved by the Invention All of these methods use a compressor as a means of creating a differential pressure across the gas separation membrane, and in the latter method, the high pressure in the membrane chamber on the high pressure side is increased by aKp/d-absst. The structure needs to be able to withstand heavy and large υ, and the compressor that generates high pressure as a pressure source also has to be large in size.In addition, the noise is also large, so it is necessary to use small storage rooms, refrigerators, etc. to save space and reduce noise. It was unsuitable for applications that require

In view of the above-mentioned problems, the present invention provides a small, low-noise nitrogen concentrator that is particularly suitable for concentrating nitrogen in a small storage container, and that is easy to adjust the concentration. A method for concentrating nitrogen in a container is provided.

Means for Solving the Problems In order to achieve this object, the nitrogen concentrator of the present invention is provided with a flat membrane opening having a higher permeation rate for oxygen than nitrogen, and a gas outlet in the second membrane chamber. Gas separation membrane module p
and a pressure reducing pump for reducing the pressure in the second membrane chamber, a supply means for supplying air to the first membrane chamber, and a supply flow rate adjustment means provided on the side of the supply means. It is something to do.

In addition, the method for concentrating nitrogen in a container according to the present invention is characterized in that the nitrogen-concentrated gas obtained from the nitrogen concentrator described above is supplied into the container.

Function: With the above configuration, the amount of air supplied into the first membrane chamber of the gas separation membrane module μ can be adjusted using the supply flow rate adjusting means. When removing oxygen from the air using a gas separation membrane to obtain nitrogen-enriched gas, the amount of unpermeated gas obtained from the gas outlet relative to the amount of air supplied from the gas inlet of the first membrane chamber If the recovery rate is the ratio of
τ, 310 Torr and the ratio of oxygen permeability coefficient to nitrogen permeability coefficient P02/PN2=2.6. Nitrogen concentration can be easily adjusted. On the other hand, in the method for concentrating nitrogen in a container using the nitrogen concentrator of the present invention, it is easy to adjust the nitrogen concentration in the container, and the nitrogen concentration can be increased by increasing the amount of air supplied at startup and increasing the recovery rate. A large amount of nitrogen-enriched gas is pumped into the container, quickly replacing it with the normal air in the container, and as the nitrogen concentration in the container increases, the amount of air supplied is gradually reduced and recovered. By decreasing the rate, it is possible to pump in nitrogen-concentrated gas with a higher nitrogen concentration than the nitrogen concentration in the container, and it is possible to achieve the specified nitrogen concentration in the container in a much shorter time than when supplying at a constant recovery rate. It is possible to raise it with a casing.

EXAMPLE A first example of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing the structure of a first embodiment of the present invention. In the figure, reference numeral 1 is a gas separation membrane in which a polymer membrane mainly composed of dimethyl silicone is coated on a support made of a porous polyether sulfone material on a nonwoven polypropylene fiber fabric. In this example, a polymer mainly composed of dimethyl silicone was used as the material for this polymer membrane, but there is no restriction on the material as long as the permeation rates of oxygen and nitrogen are different; for example, a higher concentration of nitrogen is required. 4-methylpentene 1. Materials such as poly-7 malate, ethyl cellulose, etc., or materials with a high permeation rate such as polytrimethylsilylpropyne when a large throughput per hour is required, or these materials may be used as needed. A combination of these materials may be used. 2 is an unpermeated gas chamber, 3 is a permeated gas chamber, 2-a gas inlet, 2-
3-a is an unpermeated gas outlet, and 3-a is a permeated gas outlet. 4 is a pressure reducing pump, the suction port is the permeate gas discharge port 3 -
a to reduce the pressure inside the permeated gas chamber 3 and create a pressure difference between the permeated gas chamber 2 and the unpermeated gas chamber 2 through the gas separation membrane 1,
Due to this pressure difference, the gas that has permeated from the unpermeated gas chamber 2 to the permeated gas chamber 3 is discharged. 5 is a supply pump, the suction port of which is connected to the unpermeated gas discharge port 2-b of module p. This supply pump 6 is driven by a DC motor, and the supply amount can be changed by changing the voltage. Note that the drive source for the supply pump 6 is not limited to a DC motor, but may be an AC motor driven by an inverter system.

Although a pump is used in this embodiment, it is not limited to a pump as long as it has an air blowing function, and any of an axial fan, a sirocco fan, etc. may be used.

The pressure reduction pump 4 of the nitrogen concentrator configured as above is operated to reduce the pressure in the permeate side membrane chamber to -4tsowxHti i, and the nitrogen concentration obtained is measured by changing the recovery rate by changing the capacity of the supply pump 5. The result was as shown in Figure 2.

In this example, the supply amount of the supply pump was adjusted by controlling the rotation speed of the motor, but it is also possible to control the supply amount using the valve 5-a as shown in Fig. 3. . In this example, the unpermeated gas discharge port and the suction port side of the pump were connected to the mounting position of the fourth supply pump.
It is also possible to connect the discharge port of the supply pump and the gas inlet as shown in the figure. A large pressure difference can be achieved, and nitrogen concentration efficiency can be improved.

FIG. 6 is a schematic diagram showing the structure of the second embodiment of the present invention. In the figure, 11 is a gas separation membrane module p, 4 is a vacuum pump, and 6 is a supply pump.

Reference numeral 6 denotes a nitrogen concentration container, which has a capacity of 12fi and is equipped with a nitrogen concentration air inlet 6-a and a pressure adjustment port eb in the container.

The pressure reducing pump 4 of the apparatus constructed as described above is operated, and the permeation gas chamber of the gas separation membrane module 11 is heated to -450f.
By reducing the pressure at fHg i and adjusting the capacity of the supply pump, the recovery rate is fixed at 0.23 and 0.10, respectively, and the recovery rate is set at o. 3,
．． 0.15 for 100 minutes to aoO minute 1, 0 after 300 minutes
．． When the nitrogen concentration in the container was measured for the case of 08, it was as shown in Fig. 6.

As can be seen from Figure 6, when the recovery rate is relatively high at 0.23, the nitrogen concentration in the container rises quickly because the amount of nitrogen-concentrated air supplied is large, but the nitrogen concentration reached is low and the recovery rate is relatively high. At a ratio of 0.1, the achieved concentration is high, but the top of the concentration is slow. By adjusting the recovery rate, the nitrogen concentration rises quickly and it is possible to achieve a high concentration.

Effects of the Invention As described above, according to the present invention, a first membrane chamber and a second membrane chamber are provided with a flat membrane gas separation membrane having a higher permeation rate for oxygen than for nitrogen, and a first membrane chamber and a second membrane chamber are provided. a separation membrane module μ in which a gas inlet and a gas outlet are provided in the membrane chamber and a gas outlet in the second membrane chamber; a decompression pump that reduces the pressure in the second membrane chamber; supply means for supplying air to the chamber;
By providing the supply flow rate adjusting means provided on the supplying means side, a nitrogen concentrating device that is small, has low noise, and can easily adjust the concentration can be obtained. ! By supplying the nitrogen enriched gas obtained from the octopus nitrogen concentrator into the container, it is easy to adjust the nitrogen concentration in the container, and the nitrogen concentration in the container can be increased in a short time. Its practical effects are significant.

[Brief explanation of drawings]

Figure 1 is a schematic diagram showing the first embodiment of the nitrogen concentrator of the present invention, Figure 2 is a graph showing the relationship between the recovery rate and nitrogen concentration of the nitrogen concentrator, and Figures 3 and 4 are the same. A schematic diagram showing another example of the supply flow rate regulating means of the nitrogen concentrator, FIG. 5 is a schematic diagram showing a second embodiment of the nitrogen concentrator of the present invention, and FIG. 6 shows the nitrogen concentration in the container in the same device. A graph showing the relationship between
FIG. 7 is a graph showing calculated values of the relationship between the recovery rate and nitrogen concentration of a nitrogen concentrator using a gas separation membrane. 1... Gas separation membrane, 2... Unpermeated gas chamber, 2-a... Gas inlet, 2-b...
...Unpermeated gas outlet, 3...Permeated gas chamber, 3
- a... Permeated gas outlet, 4...
Decompression pump, 6... Supply pump, 6...
・Nitrogen concentration container, 6-a... Nitrogen enriched air inlet, e-b... Container internal pressure adjustment port, 11...
...Gas separation membrane module p0

Claims (2)

[Claims] (1) It has a first membrane chamber and a second membrane chamber separated by a flat membrane gas separation membrane having a higher permeation rate of oxygen than nitrogen;
The second membrane chamber has a gas inlet and a gas outlet, and the second membrane chamber has a gas separation membrane module equipped with a gas outlet and a second membrane chamber.
A nitrogen concentrator equipped with a pressure reducing pump for reducing the pressure inside the membrane chamber, and a supply means for supplying air to the first membrane chamber, characterized in that the supply means is equipped with a supply flow rate adjustment means. Nitrogen concentrator. (2) A method for concentrating nitrogen in a container, supplying the nitrogen-concentrated gas obtained from the nitrogen concentrator according to claim 1 into the container.