DE1934479A1 - Method and device for extracting a gas from a gas mixture - Google Patents

Description

The present invention relates to a method for extracting at least one gas from a gas mixture by means of a liquid phase which contains at least one extractant, the gas mixture and the liquid phase being passed into at least two extraction zones and at least two decanting zones, which is characterized in that in the first extraction zone, the gas mixture is brought into direct contact with a co-flowing, ascending liquid phase which comes from the second decanting zone, that the gas-liquid mixture leaving the first extraction zone is passed into the first decanting zone, where the separation into gas and liquid phase takes place, that one has this latter

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liquid phase enriched in extractable gas, deducts that in a second extraction zone that of the gas originating from the first decantation zone in direct contact with a co-flowing, ascending liquid phase, which contains the extractant, brings, this liquid phase having a lower content of extractable gas as the liquid phase that leaves the second decanting zone, that one is the gas-liquid mixture that is the second Extraction zone leaves into a second decantation zone leads, where it is in a gas that has only a low content of extractables, which gas is withdrawn / and into a liquid phase, which is passed into the first extraction zone and there acts as a liquid extraction zone, is separated

Another important aspect of the present invention consists in the fact that the treatment according to the invention of Gas mixtures can be carried out continuously, the liquid phase containing the extractant or this represents, after passing through a regeneration zone in which both the release and the isolation of the extractable gases, furthermore the isolation of any solid particles present by using a suitable Filters and the regeneration of the extractants used takes place, can be recycled.

The method according to the invention has, compared to the known methods of treating gases in columns, in which the known countercurrent methods are used, which can be columns with different trays or filled columns, the double advantage of significantly greater effectiveness and a jump in capacity due to the fact that the flow rates of both gases and liquids can be much greater

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and due to the fact that a device according to the invention (Apparatus) is used in which the phenomenon of back-mixing, which often occurs in the countercurrent method of the prior art working columns occurs is avoided.

Another object of the present invention is the disclosure of an extraction device, at least for the extraction of a gas from a gas mixture by means of a liquid Extraction phase containing at least one extractant, which device is characterized in that it has at least two extraction elements, each consisting of at least one tube in which an extraction process takes place, this tube having a larger free space in which the decanting takes place, and each decanting zone at its upper end an outlet tube for the gas mixture which is depleted in gas to be extracted and at its the lower part has an exit tube for the liquid phase enriched in extractable gas; the exit tube for the gas mixture the first decanting zone is connected to the pipe of the second extraction zone; the exit tube for the liquid phase the second extraction zone is connected to the tube of the first extraction zone, wherein last tube is bent at the lower part and between its lower bent part and that located in the decanting zone located upper part is equipped with a feed tube for the gas mixture to be treated.

In Figure 1 is a vertical section of an element of the invention Device shown in which the various parts and also the circulation of gases and liquids shown inside this element.

The gas to be treated arrives through the side nozzle 1 and penetrates the liquid phase, which flows through the tube 2

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is fed in. The gas and the liquid are in contact with each other in the central tube 3, whereby they through the effect of the so-called "gas lift" to the top be conveyed, the gas and the liquid circulating in the same direction in this part. At the upper end of this central tube 3 a deflector 4 is arranged, which prevents the liquid from being thrown against the discharge nozzle 6 of the gas will. The gas-liquid mixture leaving the central tube falls into the annular part 5 of this device, the gas optionally against a further element of the device according to the invention through the discharge nozzle 6 is discharged, while the liquid phase is removed through the discharge line 7, optionally with the supply 2 of the preceding element of the device according to the invention is connected and the liquid phase is therefore optionally in the upstream element of the device according to the invention fed in.

The central tube 3 »which can also be called a mixer, can be unfilled, but it can also optionally have classic fillers, such as floors or plates, Beads, rings, etc.

To make sure the gases and liquids in of the tube 2 and then rise in the central tube 3, it is necessary that the tube 2 has such a shape that prevents gas from reaching the decanting zone of the possibly upstream element of the device according to the invention flows. This is achieved by having a sufficient height difference between the tube 1 and the lowest Part of the tubes 2 creates, this height difference being referred to as the column foot.

Other conditions, such as the viscosity of the Liquid, the differential pressure between the inlet and

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the outlet of the gas, the diameter of the tubes, etc., can In each case, they are set by an expert in such a way that the device according to the invention functions as well as possible is, these measures being known per se to the person skilled in the art.

Although a single element described herein is applicable, it will generally be preferred for the purposes of To achieve greater effectiveness, use a number of such devices connected to one another. This connection of the individual elements can be vertical (please see Figure 2, in which the device "in column" is shown) as well as preferably in a horizontal manner (please see Figure 3? in which the device of a "battery" is shown is) doneι the arrangement of the individual elements can also can also be done in other ways, for example in an inclined shape, with one element each being lower than the other. For the sake of simplicity, in Figures 2 and 3 only In each case three individual elements of the device according to the invention are shown; However, it is readily apparent that the number the elements can be much larger and is not limited.

In both FIGS. 2 and 3, the direction of flow of the gas mixture to be treated is shown in broken lines, whereas the direction of flow of the liquid phase is shown in solid lines. The function of the two types of equipment, ie the column and battery, is the same; the circulation from top to bottom in the type of device according to FIG. 2 is replaced by a circulation from right to left in the arrangement according to FIG. 3 and vice versa. The liquid phase can be introduced into element III, ie into the last element of the device according to the invention, for example with the aid of a pump 8 _t whereas the gas to be treated into element I, ie into the first element of the device according to the invention

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Device is supplied via the supply line 10. The loading. acted gas leaves the last element of this arrangement, i.e. in the present case the element III, via the line 12, while the liquid phase, which the extraction agent or agents, the extracted gas (s), and possibly solid particles, contains the first element, i.e. in the present case element I, of the arrangement according to the invention the line 15 leaves.

To prevent gases from escaping through this discharge line 13, a valve or contactor 11 is arranged to control of the liquid level 14 in the decanting area of the Elements I allowed to control. This valve or this contactor can be in any known manner determine the regulation of the liquid level, for example regulation by a swimmer, by a optical device, etc., take place. The liquid phase can as such in the last element, in this case element III of the device according to the invention, or can be recycled it is preferably passed into a regenerator before recycling, in which the extraction agent or agents are regenerated and also the removal of the extracted gas or gases and any solid particles present he follows. It is easy to see that the particular nature of this regenerator depends on the one (s) to be extracted Gases, from any solid particles that may be present and depends on the extractant (s) used in each case. The invention is therefore of course in no way intended be limited to the use of a particular type of regenerator.

The selection of the respective arrangement of the individual elements of the device according to the invention, i.e. for example the arrangement by battery or in column mostly depends on the subsequent one Use of the treated gas and the overall arrangement

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tion in which the device according to the invention is installed, away. Regardless of which type of arrangement is selected, the inventive Device can very easily be reduced in size, for example for laboratory tests or for certain special applications, such as the cleaning of consumable gases from combustion chambers, the treatment for the elimination of Carbon dioxide from air in enclosed spaces, such as in submarines, the treatment of radioactive gases inside sealed rooms, such as in the so-called glove boxes, which are common practice in experiments with radioactive material.

The inventive treatment of gas mixtures according to the present The invention is applicable to most gases in the following examples are provided:

- Treatment of acidic gases, such as CO ₂ and EUS, which can be extracted using alkanolamines and acid amides, for example; this applies, for example, to the elimination of CO ₂ and H ₂ S from the mixtures CO ₂ - H ₂ , CO ₂ - N ₂ , from naturally occurring gases and from refinery gases;

- Absorption of dilute gases, such as SO ₂ , SO ,, Clp, HCl, NO ₂ , ΝΗχ »^ ₂ H ₂ , by solvents or solvent mixtures, such as water, aqueous solutions of amines, ammonia> inorganic salts, also dimethyl sulfoxide, n -Methylpyrrolidone, glycol, polyglycol, ether, ester, suIfolan and also all solvents used on an industrial scale}

- Conversion between two or more gases and subsequent absorption or absorption of several gases and conversion in the solvent environment, for example absorption of hydrogen sulfide and sulfur dioxide through a solvent and reaction of these two compounds in a solvent

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milieu with the formation of sulfur is another example is the conversion of ammonia and hydrogen sulfide with the formation of ammonium sulfide and absorption in aqueous Phase.

The essence of the present invention will now be further illustrated by the following examples, which are in no way limiting meant to be.

Example 1:

The gas mixture used in this example contains hydrogen and carbon dioxide; Gases that come from the reforming process, in which water vapor is reacted with ethanol, this reaction proceeds according to the equation: GH, QU + ■ HoO- »CO ₂ + 3 Ho * the aim is to convert this Gemisoh (3rd Parts by volume of hydrogen come to 1 part by volume of carbon dioxide) to obtain the hydrogen, freed from carbon dioxide, which can then be used directly, for example as fuel in a combustion chamber

The apparatus used consists of 6 elements as they continue have already been described in detail above and which are connected as a battery; each element has a diameter of 3 cm and a height of 25 cm.

The extractant used consists of ethanolamine, which is dissolved in dimethyl sulfoxide, with equal proportions by volume of these two substances is used in the extraction agent (50 parts by volume of ethanolamine and 50 parts by volume of dimethyl sulfoxide). The throughput of extractant is 2.8 hours / hour. The extractant is regenerated in a reactor consisting of a tubular heat exchanger, the outlet of which communicates with the air through which the discharge of carbon dioxide takes place.

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This reactor is heated to 140 ° C. The ethanolamine solution leaves the top element and contains the extracted Carbon dioxide; it passes through the regenerator, in which the desorption of the carbon dioxide takes place} then the ethanolamine solution is recycled back into the end element.

The gas mixture that comes from the reactor in which the Reforming process is taking place with a throughput of

1 m * / h fed into the top element. After it has passed through the 6 elements of the device according to the invention, the hydrogen only has traces of carbon dioxide, ie its 00 ₂ content is less than 0.1% by volume.

Example 2:

The apparatus mentioned in the previous example is used for the treatment of methane combustion gas, with the aim of to extract nitrogen and carbon dioxide from this individually, which can then be used directly, for example for preserving fruits.

The combustion gases of the methane are at a throughput of

2 mvh treated with an extractant, which is made up of a mixture of ethanolamine and n-methylpyrrolidone im Volume ratio 50:50 and that in a throughput of

3 liters / hour is applied.

The gas flowing out of the device according to the invention in an amount of 1.4-5 m ^ / hour consists essentially of Nitrogen.

The desorption of carbon dioxide from the amine solution is at 140 ⁰ O in a regeneration reactor which was written in Working Example 1 is performed, so that one thereby a

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The regenerated amine will be as in the previous example is recycled to the end element of the battery used.

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Claims (1)

- sheet 11 - Claims 1.) A method for extracting at least one gas from a gas mixture by means of a liquid phase which contains at least one extractant , the gas mixture and the liquid phase being passed into at least two extraction zones and at least two decanting zones, characterized in that in the first Extraction zone brings the gas mixture flowing in the same direction and ascending in direct contact with the liquid phase, which comes from the second decanting zone, that one passes the gas-liquid mixture originating from the first Extraktionsζone into the first decanting zone, in which it is in gas phase and Liquid phase is separated, that this latter liquid phase, which is enriched in extractable gas, is withdrawn, that in a second extraction zone the gas originating from the first decanting zone is brought into direct contact with a liquid phase, which contains the extractant, flowing in the same direction and ascending this liquid phase has a lower content of extractable gas than the liquid phase that originates from the second decanting zone and that the gas-liquid mixture leaving the second extraction zone is passed into a second decanting zone , in which it is converted into a gas that has a low content of extractable ingredients and which is withdrawn and separated into a liquid phase , the latter of the former. Extraction zone for use as a liquid extraction phase is fed. 2.) Procedure according to. Claim 1, characterized in that the extraction is carried out continuously, whereby one 909883/1550 -12- - sheet 12 - the liquid from the first decanting zone Extraction phase, the access to the second extraction zone recycled after the liquid extraction phase has passed a regenerator was passed in which the removal and isolation of the extracted gas takes place. 3 ·) Device for extracting at least one gas from a gas mixture by means of a liquid extraction phase which contains at least one extractant characterized in that it consists of at least two extraction elements, each formed from a tube in which the extraction takes place and this , Tube has a space larger in diameter than the decanting zone, further this decanting zone with a Discharge pipe for the gas mixture, which is depleted in extractable gas, at its upper end and one Discharge line for the liquid phase, which is connected to extra- - Is enriched herebarem gas, has at its lower end that also the discharge line for the Gas mixture of the first decanting zone with the line of the second extraction zone and the discharge for the liquid phase of the second decantation zone is connected to the line of the first extraction zone, wherein the latter duct is bent at its lower part and between its bent part and the upper one Part that extends into the decanting zone with a feed line for the gas mixture to be treated Is provided. 4 ·.) Device according to claim 1, characterized in that each extraction tube is provided at its upper part with at least one deflector which prevents the liquid phase can escape with the gas mixture. 5.) Device according to claim 5, characterized in that 90 9883/1550 -15- - sheet 13 - each feed line for the gas mixture of an element with the output line for the gas mixture of the preceding element is connected, that also each outlet line for the liquid Phase is connected to the supply line for the liquid phase of the previous element, that the liquid extraction phase, which is enriched in gas to be extracted, through a valve from the outlet line for the liquid phase of the uppermost element is isolated, which allows the liquid level of the uppermost element to increase control that the gas to be treated, which is fed into the uppermost element, is at the outlet of the end element is isolated. 6.) Device according to claim 5 »characterized in that the individual elements of the device are arranged in such a way that, in terms of the circulation of the gas, a constant increasing level is present. 7 ·) Device according to claim 5 »characterized in that the individual elements are arranged on the same level. 8.) Device according to claim 5 »characterized in that the feed line for the liquid phase of the last Elements / & re discharge line for the liquid phase of the first element are connected to one another in order to ensure recycling of the liquid phase. 9.) Device according to claims 3 and 5 »characterized in that the liquid phase containing the barren extractant and the or the extracted gases may be passed through a regenerator, which is intended to receive the or extracted gases and particles optionally present solid to eliminate with simultaneous regeneration of the 909883/1560 " - Sheet or the extractant as a liquid phase before its cyclization. 909883/1550