JPS61268338A - Selective separation of gas - Google Patents

Abstract

PURPOSE:To obtain a gas selective separation membrane selectively separating carbon monoxide especially from a gaseous mixture, by holding a liquid composition containing a copper compound and dimethylsulfoxide to a support membrane having a skin layer to use the same in a fluidized state. CONSTITUTION:A copper compound such as cuppric chloride and dimethylsulfoxide (DMSO) are pref. mixed in a ratio of 0.5<DMSO/copper compound <50 (mol. ratio) to obtain a liquid composition. At this time, vanadium trichloride may be added in a mol. ratio of 0.2 or less based on the copper compound and a proper solvent may be used. The obtained liquid composition is held to a support membrane having a skin layer and a gaseous mixture is contacted with the primary side while the liquid composition is brought to a fluidized state by stirring, bubbling or an ultrasonic wave and the secondary side of the membrane is reduced in pressure to selectively take out specific gas, especially, carbon monoxide.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for selectively separating gases. Specifically, a gas mixture is prepared by holding a liquid containing a copper compound and dimethyl sulfoxide in a membrane having a skin layer as a support, and using the liquid as a gas selective separation membrane while forming a fluid state in the liquid from the outside. The present invention relates to a method for selectively separating a specific gas, particularly -carbon oxide (hereinafter abbreviated as CO).

[Conventional technology]

Conventionally, various polymer membranes have been known as separation membranes for gas mixtures, but these membranes have large gas permeation coefficients, solubility coefficients, and diffusion coefficients for one gas, and therefore can have large permeation coefficients. Furthermore, if such a liquid membrane contains a substance that selectively and reversibly interacts only with a certain gas, it is possible to further increase the permeability of that gas. On the other hand, the selective performance of a membrane is given by the difference in mutual solubility of gases in the membrane and the difference in the diffusion rate of gases in the membrane, so substances that selectively and reversibly interact only with specific gases such as those mentioned above When it is included in the membrane, the solubility of only that gas is high (and the selectivity can be dramatically increased).

Many examples are known of such membranes containing substances that selectively and reversibly interact only with certain gases. !;-1174), separation of olefins using silver nitrate aqueous solution (Tokukosho!r3-31gl12
), Separation of nitric oxide using a formamide solution of ferrous chloride (A, Engineering Journal vol. 1/
AA,? 40 J-Bage 1920), etc., and these liquid membranes are used by being held on a membrane that serves as a support. Also, for the separation of carbon oxide, an aqueous solution of copper chloride in hydrochloric acid (
Tokukai Akira! S-Tada 6:16, j! -13ri02g is known, but in this case there is a problem with the durability of the container because it requires the use of a concentrated aqueous hydrochloric acid solution.
Furthermore, there is a problem in that the dissipation of water due to the pressure difference causes a change in concentration, resulting in a decrease in performance. Furthermore, when reducing the pressure on the secondary side (outflow side) of permeation, there is a problem that water vapor and hydrogen chloride gas permeate and mix with other gases.

As a method for separating and concentrating CO from a gas mixture containing CO, an ammoniacal cuprous aqueous solution, a hydrochloric acidic cuprous aqueous solution, and a toluene solution of copper aluminum chloride known as the 0O8ORB method (British Patent No. 1.J) are used. /ff
, No. 790] or a copper compound and a metal (excluding copper) chloride and an acid-containing organic solvent or pyridine (JP-A No. 3 Dark/7Kg, &Q-qt7g9), a copper compound and dimethyl sulfoxide transition metal chloride (JP-A No. Showa!;1.-1117
21), aprotic amides, oxyacid derivatives of phosphorus, or solutions of transition metal chlorides [JP-A-7]
g7:11. kA-J/g'l:10)fldoKOO'
An absorption method in which the substance is absorbed into the liquid, and a cryogenic separation method that is fundamentally different from these absorption methods are known. However, these methods require heating for 00 dissociation.

There were problems such as the equipment was expensive and the power consumption was large.

[Purpose of the invention]

As a result of studying the above-mentioned cuprous chloride-dimethyl sulfoxide-transition metal chloride mixture or reaction product as a fluidized carrier membrane, we found that it exhibits extremely high separation performance and permeation rate when used in a stirred system. The present invention was achieved by discovering that the effect of the fluid state is remarkable, and that the heathered yarn exhibits higher separation performance under stirring than that without stirring.

[Structure of the invention]

That is, the gist of the present invention is to provide a method for selectively separating a specific gas in a mixed gas using a liquid material containing a copper compound and dimethyl sulfoxide. This gas selective separation method is characterized in that the gas is retained in a membrane having a skin layer, and the liquid is used while being allowed to flow. The present invention will be explained in detail below.

The copper compounds used in the present invention are not particularly limited, but include:
Cuprous chloride, cuprous chloride, cuprous oxide, cuprous oxide, cuprous bromide, cupric bromide, i/copper cyanide, cuprous cyanide, silver thiocyanate, fluoride Copper, copper iodide, copper sulfide, copper sulfate, etc. are exemplified, and these can be used alone or as a mixture. Among these, cuprous chloride, cuprous iodide,
Cuprous thiocyanate and the like are particularly suitable copper compounds.

The gas selective separation membrane used in the present invention is a liquid material containing a substance that has a reversible interaction with CO, and is characterized by containing a copper compound and dimethyl sulfoxide.

In a liquid containing a copper compound and dimethyl sulfoxide, a mixture of the two or a reactant (complex) of the two is thought to function as a substance that has a reversible interaction with CO.

If the copper compound and dimethyl sulfoxide are commercially available products, they may be used as they are or may be further purified.

When dimethyl sulfoxide (hereinafter abbreviated as DMSO) is used under conditions where it is a liquid, DM80 itself can be used as it is as a solvent.

However, other solvents can also be used in combination.

If it can be used as a solvent as it is, the concentration of substances that reversibly interact with specific gases, such as carbon monoxide, will be high, which is advantageous for facilitated transport.

May be used, such as ketones, esters, ethers,
Alcohols, amines, amides, other 1-nitrogen compounds, sulfur-containing compounds, phosphorus-containing compounds, 1-containing compounds, etc. are suitable in that they dissolve well in DMEIOQ, but when reducing the pressure on the secondary side of permeation, Because these compounds have high vapor pressure, they have the disadvantage of passing through as vapor and mixing with other gases.Copyrrolidone, γ-butyrolactone, ethylene glycol, tetraethylene glycol, dimethyl ester, polyethylene glycol, chrycerin, benzoic acid ether , hexamethylphosphoric triamide, imidazole, pyrazole, triazole, tetrazole and the like, room temperature is sufficient.

When carrying out the reaction at a higher temperature, it is preferable to form a homogeneous solution at an ambient temperature from the viewpoint of ease of solid state manipulation. In order to improve the dispersibility of the copper compound in the solution, vanadium trichloride or the like may be added to the above components by a known method (JP-A-Sho AiA-/
If Ig7.22) is a liquid, it is usually DMSO/copper compound>0.1-10,000. If a bath medium is used, the ratio of DMSO to solvent is usually J) M80/@ medium>θ, 00/C mol/liter. ) or more are selected.

In this case the ratio of copper compound to DMSO is selected as above.

The liquid material can be prepared generally at a temperature of 0 to 200 DEG C., and is preferably carried out under an inert gas stream.

If a solvent is used, should a copper compound be prepared by dissolving DMSO in the solvent? It is desirable to add In addition, solid content (reaction product of copper compound and DMSO) can be extracted by methods such as depressurization and precipitation.
After taking it out, it may be dissolved again in a dissolvable solvent.

Regarding the composition ratio of the system containing vanadium trichloride, the molar ratio of copper compound to vanadium trichloride is f o, θ ≦vanadium trichloride/copper compound ≦0. In selecting the molar ratio, in addition to the one that does not volatilize on the permeate side, the viscosity of the liquid is low and the 11'il stability is good. It is preferable that there be.

'□'Next, a membrane having a skin layer can be used as a support used to hold the thus obtained liquid material containing a substance that reversibly adsorbs and desorbs only a specific gas. By retaining a substance that reversibly adsorbs and desorbs Mj only with a specific gas in the membrane having this skin layer, it is possible to prevent droplets from flowing out even if the pressure on the permeate side is reduced.

That is, the primary side of the membrane is brought into contact with a mixed gas containing the above-mentioned specific gas for the purpose of selective separation, and the primary side (permeation side) of the membrane is
By reducing the pressure to a pressure lower than atmospheric pressure, it becomes possible to selectively extract the specific gas. Especially if the membrane having a skin layer does not allow liquid droplets to pass through it, ii? It is not limited to lI, but includes asymmetric membranes, composite membranes, homogeneous membranes, and the like.

In other words, a membrane formed by a method that forms a membrane having both a porous layer and a dense layer by a one-step weir membrane operation from a membrane-forming solution, and a monomer applied onto a pre-formed porous membrane. Membranes formed by polymerization to form a single layer of polymer, membranes in which a plasma polymerized layer or vapor deposited layer is similarly formed on a porous membrane, and a membrane formed by coating a porous membrane with a polymer solution.
Examples include a membrane with a polymer skin formed by crosslinking reaction or evaporation of a solvent, and a membrane laminated on a thin, homogeneous porous membrane.

The materials of the skin layer and the porous layer may be the same or different.

In addition, as a method for retaining the above-mentioned substance in a membrane that serves as a support, the above-mentioned substance may be incorporated into a crosslinkable polymer network formed on the support membrane. The types of materials are not particularly limited, but include regenerated cellulose, cellulose ester, polycarbonate, polyester, Teflon, nylon, acenal cellulose, polyacrylonitrile, polyvinyl alcohol, polymethyl methacrylate, polysulfone, polyethylene, polypropylene, polyvinylpyridine, polyphenylene oxide. , polyphenylene ogicide sulfonic acid, polybenzimidazole, polyimidazopyrrolone, polypiperazine amide, polystyrene, polyamino acid, polyurethane, polyamino acid polyurethane copolymer, polysiloxane, polysiloxane polycarbonate copolymer, poly trimethylvinyl-lucirane, collagen, polyion complex, polyurea,
Polyamide, polyimide, polyamideimide, polyvinyl chloride, sulfonated polyfluoride The shape of these supports is not limited to flat, tubular, spy, etc., but ranges from 10 to 000μ. ,.,: O4
M fi ”i n K &-!,'ff K fll
JOX! .

It can also be used by stacking it on a support.

The thickness of the skin layer is preferably 10A-100μ/QQA
- used in the range of IQμ.

Methods for forming a fluid state in a substance that reversibly adsorbs and desorbs only a specific gas include stirring, bubbling, vibration (such as ultrasonic waves), and quiet circulation of the substance itself.

In other words, a substance C that reversibly adsorbs and desorbs only a specific gas.
A method for keeping a liquid material including a carrier liquid in a fluid state is to make a space containing a flat, tubular, or hollow fiber support membrane and a liquid material flow by rotating a stirring blade, or to use a pump or the like to enter the space from the outside. There are methods to flow by sending in a flux of liquid (carrier liquid), methods to move by rotating the support membrane itself, and methods to flow by blowing gas into the membrane surface from the outside, but / rpm~
It is also possible to use a method in which a container containing a solution at a speed of 10,000 rpm, preferably 1000 rpm, is drained, and the liquid is introduced to the surface of the support membrane (primary side of the membrane) of the membrane cell using a pump and circulated. In this case, there is a method of highly selectively and continuously taking out a specific gas by sufficiently absorbing a specific gas into a liquid in a reservoir container and then performing this membrane-wise in a membrane cell. You can also use

In this case, the temperature of the membrane cell and the reservoir can be made different to facilitate extraction of a specific gas. The temperature of the membrane cell portion is not particularly limited, but may be, for example, 0-. It can be used within the range of 200℃.

〔Example〕

10 ml of oxygenated solution was added and stirred.

When heated at tro.degree. C. for 3 hours, a slurry-like brown solution (carrier solution) was obtained.

10,000, IJ l-IJ methyl deviation in the cell for gas permeation measurement '0-' ~ '0-' ca/ctl ・se
a ・mHg.

The above slurry solution was poured onto this membrane under a stream of inert gas.
f, A ml was added and stirred. After reducing the pressure on both the downstream and secondary sides, a gas of /KG was flowed into the primary side, and the secondary side was evacuated and measurements were made using gas chromatography, which is permeable to various gases. Pure gas was used as the measurement gas.

The results are shown in Table-7. - Only carbon oxide gas was selectively promoted. The measurement temperature was 5°C.

Also, with this method, not even 7 droplets of MEIO permeate to the secondary side during the experimental operation, and since the vapor pressure of DMSO is low, the vapor of DMSO also does not permeate.=15- An advantage? [I experimented with a trap tube, but not a single drop was collected.] ).

Example: Cuprous chloride under drying current (commercial product used as is)
/, 09g and vanadium trichloride.

By the same method as in Example 1 except for using this solution,
The permeation rate of various gases was measured.

(Measured temperature t, rr:,) Results are shown in Table 7.

As can be seen from the table, in a homogeneous system, the permeation rate of 00 was much higher than that of other gases, indicating that the permeation of only cO gas was selectively promoted.

The permeation rates of 00 and OH4 were measured.

Example 3 The permeation rates of various gases were measured in the same manner as in Example 3, except that 1.90 fl of cuprous iodide (a commercially available product was used as is) was used instead of cuprous chloride. [Measurement temperature: 27°C] The results are shown in Table No.

As seen from the table, only 00 gas was selectively promoted in permeation.

・Comparative Example: The same carrier solution as in Example 3 was applied on the same membrane. “niO
, in addition to making the film thickness as small as 00 in the stationary state.
The permeation rate of and OH4 was measured.

As shown in Table 1, the permeation rate of co, C
Both O and OH separation ratios decreased.

Example G: Amount of cuprous chloride and vanadium trichloride used? The permeation rates of various gases were measured in exactly the same manner as in Example 1, except that SI, SI and SI of 0.379 were used. (Measurement temperature A, j°C) The results are shown in Table No.

As can be seen from the table, the permeation rate of CO is very high compared to other gases, and only CO gas is selectively taken into the Sco, where l-methylimidazole (dehydrated and deoxidized commercially available product) is added. /Oral addition (measurement temperature: 2g°C) As shown in Table 1, only 00 gas was selectively promoted in permeation.

Comparative Example DA The same carrier solution as Comparative Example 3 was applied on the same membrane.
In addition, the permeation rate of CO and OH4 in a static state was measured so that the film thickness was equal to crrL.

(Measurement temperature, 2t''C) As shown in Table 1, the CO permeation rate is lower than in the stirring state of Comparative Example 3;
There was only a slight decrease in the separation ratio of and OH4.

〔Effect of the invention〕

According to the gas selective separation method of the present invention, carbon monoxide can be obtained in high yield mainly from a mixed gas containing carbon monoxide obtained as a by-product gas of two-coal gasification and iron manufacturing, and can be used in various chemical reactions. It can be used as a raw material.

Claims (2)

[Claims] (1) In a method of selectively separating a specific gas in a mixed gas using a liquid containing a copper compound and dimethyl sulfoxide, the liquid containing a copper compound and dimethyl sulfoxide is separated from a skin layer serving as a support. 1. A method for selectively separating gases, characterized in that the liquid substance is held in a membrane containing a liquid substance and used while flowing the liquid substance. (2) Claim 1 describes the use of a liquid containing vanadium trichloride in a molar ratio of 0.2 or less to the copper compound as the liquid containing the copper compound and dimethyl sulfoxide. separation method.