DD204625A1 - METHOD FOR PRODUCING AN ADSORBENT MORELENITE-CONTAINING RHIOLIUM SURFACE FOR THE SEPARATION OF OXYGEN AND NITROGEN CONTAINING GAS MIXTURES - Google Patents

Abstract

The present invention relates to a process for producing an adsorber from at least 25% mordenite-containing rhodium surfers. The adsorber thus prepared can be used as a filling in adsorption plants used for the separation of air. According to the invention, the suitable rock, after comminution or subsequent granulation, is treated with an aqueous solution of a sodium salt at 290 K to 400 K. During the treatment, the content of sodium ions of the rock increases. The rock is activated in vacuum or in an inert gas stream at 600 to 900 K and the resulting adsorber adsorbs the nitrogen faster, more intense and in a larger amount than the oxygen.

Description

14 894 55

-A-

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Process for the preparation of an adsorber of mordenite

containing Rhiolitturfen

Field of application of the invention;

The present invention is a process for the preparation of an adsorber from, as a mineral component mordenite-containing, Rhiolitturfen. The rock converted according to the invention (Turf) adsorbs the nitrogen more intensely than the oxygen and is therefore suitable as a filling of Adsorbtionsanlagen, which are used to produce oxygen and / or nitrogen or gases enriched in oxygen and / or nitrogen from air.

Characteristic of the known technical solutions;

The use of zeolites as adsorbent is known. Such substances have long been used for the selective separation of molecules of different particle size as a result of their action as a molecular sieve.

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When molecules of little different particle size need to be separated, e.g. in the separation of oxygen and nitrogen, such an adsorber must be prepared which adsorbs one or more of the gas components more than the other components. Some synthetic zeolites or natural zeolite containing rocks can be used for selective adsorption of the nitrogen from the air, whereby an effective adsorption technology can be worked out to separate the components of the air.

The known gas absorption methods for the separation of gas mixtures are based in most cases on the change in the adsorption capacity due to the change in Temperatur.oder pressure. The adsorption technologies of air separation achieve the desired effect mainly by a pressure change; in general, short adsorption and desorption times are used. These methods are known as "pressure swing adsorption" (PSA) methods. The individual patents describing the various PSA devices also contain an indication of the adsorbers that can be used in air separation.

DE-PS 1,265,724 holds the galactic ions or strontium ions containing synthetic molecular sieves type A zeolite for the selective removal of nitrogen from the air as suitable. According to DE-PS 2 312 710 zeolites are used as adsorbers, preferably of type 5A or sodium mordenite.

The above-mentioned and the air separation related patent. Fonts suggest only the commercial synthetic zeolites as useful adsorbers and are not concerned with increasing the selectivity of the adsorbers to make the process more effective. Already the relatively expensive synthetic zeolites have been replaced by cheaper adsorbers. According to JP-73 151/1965, e.g. zerklei-

- 3 -

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used and previously thermally treated rocks for air separation.

Object of the invention:

The aim of the invention is the production of such adsorbers, whose selective adsorption capacity over nitrogen is significantly better than those previously used for air separation and which can be easily and economically produced from mineral rocks,

Explanation of the essence of the invention;

The present invention is based on the finding that certain rhodanites also containing mordenite as a mineral component, which have a pore volume of 0.38 cnr / g at a pore diameter of 7.5 Hm to 7500nm, by treatment with a solution containing sodium ions or melt at 290 to 400 ⁰ K and by dehydration at 600 to 900 ⁰ K in a suitable for the separation of the main components of the air selective adsorber can be converted.

In addition to mordenite, the rocks may contain clinoptilolite, quartz, montmorillonite and other zeolites and / or crystalline or amorphous mineral components that do not adversely affect the adsorptive capacity of the mordenite-containing rock.

A Tokay-derived rock used in the present invention has the following chemical composition:

-. 4 Table I

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Chemical composition of the rock

! Component e weight %

SiO ₂ 69,10

Al ₂ O ₃ 14,75

Pe ₂ O ₃ 1.20

Ha ₂ O. 1.50

K ₂ O 1.65

MgO 0.52

CaO 2.02

MaO 0.32

TiO ₂ 0.08

Annealing loss 8.80

The X-ray diffraction data of the rock are summarized in Table II. From the X-ray diffractogram it can be seen that the rock contains mordenite. The mordenite content is the prerequisite for the preparation of the adsorber according to the invention. A rock is suitable for producing the adsorbent when the mordenite content is at least 25 % .

- 5 - Table II

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The main X-ray diffraction lines of the rock used as the basic material

13.55 20

9.05 60

6.57 50

6.05 10

5.79 20

4.51 40 4.25

3,98 60 3,77

3,64 10

3.47 100

3.39 60 3.35

3,22 80 3,19

2,89 30

Relative line intensities ciiarakteristisch for murders · nit

The chemical composition and the X-ray diffractograms of the rocks which can be used according to the invention can deviate more or less from the values given in Tables I or II in the mineral composition.

Before ion exchange or afterwards, the rock is comminuted to obtain the appropriate particle size and distrubution, and optionally with the addition of a binder, e.g. Alumina, granulated.

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Rocks which are suitable for the preparation of the adsorber, in an amount of 0.5 to 2.4 such cations

which can be replaced with other cation by treatment with a solution containing NIL.sup.- or metal ions or melt. If a suitably selected grain fraction or granulated or arbitrarily formulated variation of the rock is treated with a Na ion-containing solution or melt, under certain circumstances it can be achieved that the content of sodium ions of the rock is increased compared to the content of further alkali and alkaline earth metal ions , In ion exchange, in addition to sodium, potassium, calcium, magnesium, iron, barium, strontium, or any other metal ion may also be introduced. The pretreated material must be activated before use as adsorber. During activation, the rock and so does the mordenite water, so that the pores adsorb better. The dehydration of the rock is achieved by heating to at least 600 ° K, optionally by simultaneous evacuation or by purging with an inert gas stream. The activation should be carried out below 900 ⁰ K, because above this temperature, the structure of the mordenite can be destroyed, whereby the adsorption capacity is reduced.

By means of the process according to the invention, it is possible to produce an adsorbent from inexpensive basic materials and with a simple technology, which is suitable for the successful separation of the main components of the air. The following examples illustrate the favorable properties of the adsorbent as well as the most important details of the process.

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EMBODIMENTS EXAMPLES Example 1

10 g of a grain fraction with the particle size 1-1.6 mm of a Tokaj mountains, 50 % mordenite-containing Rhiolitturfes are heated in 60 ml of a 1 η NaCl solution under reflux for 4 hours, the solution is then replaced by a fresh Salt solution replaced and heated again 4 hours. The solution is decanted off and the rock washed with distilled water.

The thus pretreated rock is sucked off at 600 ° K for 8 hours at 10 Pa. The adsorption capacity of the resulting adsorber at 293 K and 10 ^ Pa is based on oxygen:

^mo1 and based on nitrogen:

Example 2

To 10 g of a grain fraction with the particle size 250-400, to a, 50 % mordenite-containing, Rhiolitturfes are added 60 ml of a concentrated NaCl solution and the solution is refluxed for 4 hours under reflux. The solution is decanted off and the same amount of fresh solution is added and heated for a further 4 hours. The rock is decanted off, dried and applied to a 1.2 m gas chromatographic column. The column is gradually heated to 600 ⁰ K and held for 4 hours at this temperature, while passing nitrogen through the column. The column containing the thus activated adsorber is installed in a CHROM IV type gas chromatograph, thermostatted at 293 K, and 1 ml of an air sample is introduced into the chromatograph at a helium carrier gas velocity of 20 ml / min. According to the well-known formula of Spit

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z decomposition (R _Q ) is the value of the separation 35 s / ram, this value is higher from the viewpoint of air separation than those of samples prepared by ion exchange so far.

With an ion-exchanged according to Example 1, at 65O ⁰ C and 100 kPa in dry air lihiolitturf activated was prepared at room temperature with a working according to the PSA-type apparatus, a 95% oxygen-containing gas mixture.

The column of the PSA device was 2 m high and the inner diameter of the column was 3 cm. The mass of the adsorber was 3 kg. The apparatus worked continuously as described below: the column and adsorber were evacuated to the final pressure of 1 kPa, then filled with predried air to 400 kPa, and then the oxygen-enriched gas was purged to 350 kPa.

The use of the adsorber according to the invention has the unexpected advantage over the known adsorbers that due to the peculiar texture of the adsorber, the adsorption and desorption proceeds much faster.

The process of the invention enables the production of oxygen or oxygen-enriched air to solve various industrial, agricultural and environmental protection tasks.

Claims (5)

- 9 claim of invention: A process for the preparation of an adsorber of mordenite-containing rhodium-based compounds which is suitable for separating the main components of the air, characterized by comprising a rock or mordenite mineral containing at least 25 % mordenite and optionally other zeolites and / or crystalline or amorphous mineral components a pore diameter of 7.5 .mu.m to 7500 nm has a pore volume of 0.38 cm / g, treated with a sodium ion or possibly other metal ions containing ionausaus.henden solution or melt and the ion-exchanged material at 600 to 900 ⁰ K by evacuation or Gas flushing activated. 2. The method according to item 1, characterized in that one uses as rock except mordenite, clinoptilolite or other zeolites and / or crystalline or amorphous mineral components containing rocks. 3. The method according to the items 1 or 2, characterized in that the mordenite-containing rock or the mordenite mineral before the ion exchange or subsequently comminuted, the corresponding particle size and distribution ensures and granulated the substance with binders bar or binder without. 4. The method according to any one of items 1 to 3, characterized in that one carries out the ion exchange with the aqueous solution of any sodium salt at a temperature of 290 to 40O ⁰ K. 5. The method according to any one of items 1 to 4, characterized in that one introduces into the rock except the sodium ions by ion exchange potassium, calcium, magnesium, iron, barium, strontium or other metal ions.