JPH07265695A - Oxygen enriching adsorbent - Google Patents

Abstract

PURPOSE:To obtain an oxygen enriching adsorbent with which stable operation is executed against a fluctuation in temp. by consisting this adsorbent of a mixture composed of A type zeolite of a specific Ca ion exchange rate and X type zeolite of a specific Ca ion exchange rate and mixing both in such a manner heat the ratio of the A type zeolite to he total of the A type zeolite and the X type zeolite is a specific ratio. CONSTITUTION:This oxygen enriching adsorbent consists of the mixture composed of the A type zeolite having the Ca ion exchange rate of >=40% and the X type zeolite having Ca ion exchange rate of >=50% and both are so mixed that the ratio of the A type zeolite to the total of the A type zeolite and the X type zeolite is 30 to 70wt.%. The adsorbent otherwise consists of the mixture composed of the A type zeolite and the X type zeolite and the Ca ion exchange rate to the total zeolite components thereof is >=50%, and further both are so mixed that the ratio of the A type zeolite to the total of the A type zeolite and the X type zeolite is 30 to 70wt.%. Consequently, oxygen is separated from a gaseous mixture contg. oxygen and nitrogen at 0 to 50 deg.C and at an approximately specified yield and treating capacity even if there is the temp. fluctuation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure fluctuation adsorption method in which nitrogen is adsorbed from a mixed gas containing oxygen and nitrogen to obtain a gas rich in oxygen, and the adsorbed nitrogen is desorbed by desorption to regenerate the adsorbent. The present invention relates to an oxygen-enriched adsorbent which is used in (PSA method) and the like and is hardly affected by the raw material gas temperature and the outside air temperature.

[0002]

2. Description of the Related Art Conventionally, as a PSA method which is not easily affected by the temperature of the raw material gas and the temperature of the outside air, an adsorption tower in which CaA type zeolite is packed in the inlet side of the adsorption tower and CaX type zeolite is packed in the outlet side of the adsorption tower. Is known (Japanese Patent Laid-Open No. 4-293513).

[0003]

DISCLOSURE OF THE INVENTION The present invention is 0 to 50 ° C.
Therefore, it is an object of the present invention to provide an oxygen-enriched adsorbent capable of performing a more stable operation with respect to temperature fluctuations than by the method proposed in JP-A-4-293513. is there.

[0004]

The present invention relates to A-type zeolite having a Ca ion exchange rate of 40% or more and Ca.
An oxygen-enriched adsorbent, which is composed of a mixture with an X-type zeolite having an ion exchange rate of 50% or more, and in which the ratio of the A-type zeolite to the total of the A-type zeolite and the X-type zeolite is 30 to 70 wt%, and A. It is composed of a mixture of type zeolite and type X zeolite, has a Ca ion exchange rate of 50% or more in all the zeolite components, and the ratio of type A zeolite to the total of type A zeolite and type X zeolite is 30 to 7.
The gist of the oxygen-rich adsorbent is 0 wt%.

The present invention will be described in detail below.

The Ca ion exchange rate of the zeolite component in the oxygen-enriched adsorbent of the present invention is 40 for A-type zeolite.
% And more than 50% in type X zeolite, or more than 50% in all zeolite components. If the Ca ion exchange rate does not reach these ranges, the nitrogen adsorption capacity is insufficient and sufficient oxygen enrichment performance cannot be obtained. In particular, it is preferable that the amount of A-type zeolite is 50 to 90%, the amount of X-type zeolite is 60% or more, or the amount of all zeolite components is 60% or more.

The ratio of the A-type zeolite to the total of the A-type zeolite and the X-type zeolite is 30 to 70% by weight.
(That is, X-type zeolite is also 30 to 70 wt%). This is because if the proportions of A-type zeolite and X-type zeolite deviate from these ranges, the temperature dependence of the adsorption performance becomes large. The ratio is 40-6
0 wt% is particularly desirable.

The oxygen-enriched adsorbent of the present invention may be any as long as it contains CaA type zeolite and CaX type zeolite having the above-mentioned Ca ion exchange rate in the above-mentioned ratio.
Examples thereof include a mixture of an aA-type zeolite molded body and a CaX-type zeolite molded body, a molded mixture powder of CaA-type zeolite and CaX-type zeolite, and the like.
Also, the more zeolite component, the higher the adsorption separation performance, so the zeolite crystal content is 70 wt%.
The above is preferable. Furthermore, a mixture of a binderless A-type zeolite molded body and a binderless X-type zeolite molded body in which the binder is crystallized to have a zeolite crystal content of 90 wt% or more has a further excellent adsorption separation performance, preferable.

The oxygen-enriched adsorbent of the present invention may be produced by a conventional method or its modification.
For example, a mixture of a CaA-type zeolite molded body and a CaX-type zeolite molded body has a Ca ion exchange rate of 50% or more after mixing the NaA-type zeolite molded body and the NaX-type zeolite molded body. Ion exchange or separate CaA exchange between the NaA type zeolite molded body and the NaX type zeolite molded body until the Ca ion exchange rate of the former becomes 40% or more and that of the latter becomes 50% or more. It can be manufactured by mixing after performing. There is no particular limitation on the method of mixing the molded body with the molded body. For example, the A-type zeolite molded body and the X-type zeolite molded body are supplied to the mixing vessel at a constant flow rate so as to have a desired mixing ratio and stirred. Just mix.

After the Ca ion-exchanged adsorbent is dried,
Minimum temperature for removing water in zeolite pores 30
Maximum temperature 700 ° C at which zeolite crystals do not collapse from 0 ° C
It is preferable to activate by firing at a temperature in the range of up to. At this time, it is more preferable that the partial pressure of water vapor in the drying and firing atmosphere is as low as possible.

[0011]

The cause of the poor temperature dependence of the performance of the oxygen-enriched adsorbent of the present invention in the temperature range of 0 to 50 ° C. is presumed to be due to the following circumstances.

That is, CaA type zeolite and Ca
In all of the X-type zeolites, the higher the temperature is, the lower the effective adsorption capacity of nitrogen (the capacity obtained by subtracting the nitrogen remaining in the adsorbent after desorption from the adsorption capacity) is, the lower the temperature is. However, in the low temperature range of 0 to 50 ° C., the CaA-type zeolite has a high nitrogen effective adsorption capacity, and the nitrogen effective adsorption capacity / oxygen effective adsorption capacity ratio is still sufficient. High and oxygen effective adsorption capacity is much lower than CaX type zeolite, CaX type zeolite has low nitrogen effective adsorption capacity / oxygen effective adsorption capacity ratio; in high temperature range, CaA type zeolite has too low effective nitrogen adsorption capacity. , CaX-type zeolite has a sufficiently high effective adsorption capacity of nitrogen and a high effective adsorption capacity ratio of nitrogen / effective adsorption capacity of oxygen. That is, in the low temperature region, the decrease in oxygen recovery rate due to the adsorption of oxygen by CaX type zeolite is compensated by the high nitrogen adsorption separation performance of CaA type zeolite, while in the high temperature region, the effective adsorption capacity of CaA type zeolite is low. The high nitrogen adsorption separation performance of CaX type zeolite is supplemented. When the oxygen-enriched adsorbent of the present invention is used, the fact that the CaA-type zeolite and the CaX-type zeolite are in contact with each other and in proximity to each other causes some factor, and promotes these actions, so that 0-50 ℃
It seems that constant performance independent of temperature is exhibited in the temperature range of.

[0013]

EFFECTS OF THE INVENTION According to the oxygen-enriched adsorbent of the present invention, oxygen is mixed from a mixed gas containing oxygen and nitrogen in a wide temperature range of 0 to 50 ° C. even if there is a temperature fluctuation, it is substantially constant. It can be separated by yield and throughput.

[0014]

The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited thereto.

In the examples, "parts" are by weight. The test of oxygen enrichment performance was performed as follows.

That is, an adsorption tower having a capacity of 2 liters is filled with an adsorbent for enriching oxygen, and the atmosphere is used as a raw material gas.
The adsorption process, the regeneration process, and the recompression process are performed in this order, and PSA operation is performed at an adsorption pressure of 0.2 kgf / cm ² , a regeneration pressure of 185 torr, and a return pressure of 785 torr.
The product oxygen flow rate was controlled to be 3%. Oxygen extraction amount (product oxygen amount per unit time) and oxygen recovery rate (ratio of oxygen amount in product oxygen to oxygen amount in raw material gas)
The performance of each oxygen enriched adsorbent was evaluated by. A single adsorption time in the adsorption step was set to 1 minute, and the gas flowing out from the adsorption tower was stored in the buffer tank. Regeneration of the adsorbent was performed by evacuating from the raw material gas inlet side of the adsorption tower, and one regeneration time was 1 minute. In the recompression step, a part of the oxygen gas in the buffer tank was made to flow backward from the product oxygen gas outlet of the adsorption tower, and the inside of the adsorption tower was returned to 785 torr for 1 minute. The oxygen enrichment device has three adsorption towers arranged,
Three-tower PSA that switches the regeneration process and re-pressurization process at 1-minute intervals
The device was used.

Examples 1 to 4, Comparative Examples 1 to 4 NaA type zeolite powder (Zeoram A manufactured by Tosoh Corporation)
-4 powder) and a binder (kaolin clay) of 80 wt% and 20 wt% respectively, and Na
80 wt% and 20% of X type zeolite (Zeorum F-9 powder manufactured by Tosoh Corporation) and binder, respectively.
After firing a compact containing wt% at 600 ° C., each is subjected to ion exchange with an aqueous solution of calcium chloride under predetermined conditions, and then mixed to form a compact containing A-type zeolite, X-type zeolite and a binder in a predetermined ratio. Manufactured. Activation was carried out at 600 ° C. for 3 hours, and finally about 2 kg of the oxygen-enriched adsorbent was produced by dry weight. Ca of the obtained adsorbent
The ion exchange rate was measured and the oxygen enrichment performance was tested by the above method.

The conditions and results not shown above are shown in Table 1.
Shown in. However, in Example 1, the zeolite component 100
Per g, in the case of NaA type zeolite molded body, the amount of Ca ions is 0.94 mol, and in the case of NaX type zeolite molded body, C
Calcium chloride aqueous solution containing a ion amount of 2.64 mol 10
Ca ion exchange was carried out by contacting with 00 ml batchwise at 60 ° C. for 3 hours. In other examples, the concentration of calcium chloride was adjusted to obtain an adsorbent having a predetermined Ca ion exchange rate. Is omitted.

Examples 5 to 8 and Comparative Examples 5 to 8 A binderless NaA type zeolite molded body having a crystal content of 97% and a binderless NaX type zeolite molded body having a crystal content of 97% were mixed and then an aqueous calcium chloride solution was used. Was subjected to ion exchange under predetermined conditions to produce a molded product containing A-type zeolite and X-type zeolite in a predetermined ratio. Activation was carried out at 600 ° C. for 3 hours, and finally about 2 kg of the oxygen-enriched adsorbent was produced by dry weight. Ca of the obtained adsorbent
The ion exchange rate was measured and the oxygen enrichment performance was tested by the above method.

Table 2 shows conditions and results not shown above.
Shown in. However, in Example 4, the zeolite component 100
C. by contacting with 1000 ml of calcium chloride aqueous solution containing 1.61 mol of Ca ion per g for 3 hours at 60.degree.
a. Ion exchange was performed, and in other examples, the concentration of calcium chloride was adjusted to obtain an adsorbent having a predetermined Ca ion exchange rate, but the posting of the concentration is omitted.

Examples 9 to 12, Comparative Examples 9 to 12 Binderless NaA-type zeolite compacts having a crystal content of 97% and binderless NaX-type zeolite compacts having a crystal content of 97% were subjected to Ca ion exchange under predetermined conditions. After that, they were mixed to produce a molded product containing A-type zeolite and X-type zeolite in a predetermined ratio. The activation is carried out at 600 ° C. for 3 hours, and finally the oxygen-enriched adsorbent is dried at about 2 k
g produced. The Ca ion exchange rate of the obtained adsorbent was measured and the oxygen enrichment performance was tested by the above method.

The conditions and results not shown above are shown in Table 3.
Shown in. However, in Example 9, the zeolite component 100
Calcium chloride aqueous solution containing 0.94 mol of Ca ion in the case of NaA type zeolite molded product and 2.64 mol of Ca ion in the case of NaX type zeolite molded product per g
Ca ion exchange was carried out by contacting with 000 ml batchwise at 60 ° C. for 3 hours. In other examples, the concentration of calcium chloride was adjusted to obtain an adsorbent having a predetermined Ca ion exchange rate. Is omitted.

Comparative Examples 13 and 14 Under the same conditions as in Example 10, a binderless CaA-type zeolite molded body and a binderless CaX-type zeolite molded body were prepared, and 1 kg each was mixed without mixing them.
In 3, the former is packed in the inlet side of the adsorption tower and the latter is packed in the outlet side,
In Comparative Example 14, the latter was packed in the inlet side of the adsorption tower and the former was packed in the outlet side, and the oxygen enrichment performance test was conducted under the same conditions as in Example 10. The results are shown in Table 3.

[0024]

[Table 1]

[0025]

[Table 2]

[0026]

[Table 3]

[Brief description of drawings]

FIG. 1 is a graph showing the results of tests of oxygen enrichment performance in Examples 1 and 2.

FIG. 2 is a graph showing the results of tests of oxygen enrichment performance in Comparative Examples 1 and 2.

FIG. 3 is a graph showing the results of tests of oxygen enrichment performance in Example 10 and Comparative Examples 13 and 14.

Claims (2)

[Claims] 1. A type zeolite comprising a mixture of an A-type zeolite having a Ca ion exchange rate of 40% or more and an X-type zeolite having a Ca ion exchange rate of 50% or more, and the total amount of the A-type zeolite and the X-type zeolite is A-type zeolite. Is 30 to 7
Oxygen enriched adsorbent, which is 0 wt%. 2. A mixture of A-type zeolite and X-type zeolite having a Ca ion exchange rate of 50% or more in all the zeolite components, and A-type zeolite and X-type zeolite.
An oxygen-enriched adsorbent in which the proportion of the A-type zeolite relative to the total of the type-zeolite is 30 to 70 wt%.