JP7245699B2 - Ethylene separation method - Google Patents

Description

The present invention relates to a method for separating ethylene using a zeolite membrane.

Olefins typified by ethylene and propylene are used in the synthesis of hydrocarbon polymers, but raw materials containing unreacted olefins may remain in the reaction system after completion of the synthesis reaction. Distillation processes are used to recover the unreacted raw material olefins, which often require a large number of stages and high reflux ratios, consuming a large amount of energy. Therefore, establishment of an olefin purification process using a separation membrane that can save energy and be simplified is desired.

In recent years, a method for separating ethylene using a zeolite membrane formed on the surface of an inorganic porous support has been reported. Zeolite membranes made of zeolite are widely used as molecular sieves because they have the property of selectively allowing molecules to pass through due to differences in molecular size and shape. For example, Patent Document 1 reports the olefin separation performance of a zeolite membrane composite in which AgX-type zeolite in which Na ions in X-type zeolite are exchanged with Ag ions is formed into a film on a porous support.

However, in general, hydrocarbon-based polymers are sometimes produced in the presence of organic chlorine compounds. For this reason, zeolite membranes may be required to be able to recover unreacted olefins even after exposure to organochlorine compounds. However, Patent Document 1 does not describe the effect of organic chlorine compounds on the separation performance of the zeolite membrane composite.

JP 2015-174081 A

The present invention has been made in view of the above problems, and its object is to provide a method that can selectively separate ethylene from a gas containing multiple components by a method different from the distillation method and the pressure swing adsorption method. to do.

As a result of intensive studies, the present inventors found that a zeolite membrane whose counter ion is an alkali metal ion can separate ethylene with high selectivity even after being exposed to an organic chlorine compound. was completed.

That is, the present invention relates to separation of ethylene using a zeolite membrane exposed to a first gas containing an organochlorine compound, wherein a second gas composed of a plurality of components containing ethylene is separated from the first gas by exposure to the first gas. The method for separating ethylene comprises the step of contacting with the zeolite membrane, wherein the zeolite membrane is composed of zeolite whose counter ion is an alkali metal ion.

According to the present invention, it is possible to provide a method for selectively separating ethylene from a gas containing multiple components by a method other than distillation or pressure swing adsorption.

1 is a schematic diagram of an ethylene separation performance evaluation apparatus using a zeolite membrane. FIG.

The present invention will be described in detail below.

The present invention is a method for separating ethylene using a zeolite membrane exposed to a first gas containing an organic chlorine compound, wherein a second gas composed of a plurality of components containing ethylene is exposed to the first gas. The method for separating ethylene includes a step of contacting with the zeolite membrane (hereinafter also referred to as a “separation step”). Here, the zeolite membrane used in the separation method of the present invention is composed of zeolite whose counterions are alkali metal ions.

First, the zeolite membrane exposed to the first gas will be described.

The first gas exposed to the zeolite membrane is a gas containing an organochlorine compound. The organic chlorine compound contained in the first gas is a volatile organic chlorine compound. Specific examples include chloromethane, dichloromethane, trichloromethane, tetrachloromethane, chloroethane, dichloroethane, trichloroethane, tetrachloroethane, pentachloroethane, hexachloroethane, chloroethylene, dichloroethylene, trichlorethylene, tetrachloroethylene, and the like. In the present invention, organic chlorine compounds include structural isomers. Note that the concentration of the organic chlorine compound in the first gas is not particularly limited.

The first gas only needs to contain an organic chlorine compound, and may contain components other than the organic chlorine compound. Components other than the organic chlorine compound include, for example, components such as contained hydrocarbons, nitrogen, oxygen, and water.

The method of exposing the first gas to the zeolite membrane is not particularly limited as long as the first gas contacts the zeolite membrane. For example, the first gas is exposed to the zeolite membrane by filling the reaction vessel in which the zeolite membrane is installed with the first gas or generating the first gas in the reaction vessel in which the zeolite membrane is installed. be able to. Note that the first gas may be exposed to the zeolite membrane in a state of being pressurized or decompressed. Note that the exposure time is not particularly limited.

Next, the second gas to be brought into contact with the zeolite membrane (the zeolite membrane exposed to the first gas) will be described.

The second gas to be brought into contact with the zeolite membrane is a mixed gas composed of a plurality of components, and contains at least ethylene and components other than ethylene (hereinafter also referred to as "other components"). Note that the concentration of ethylene in the second gas is not particularly limited.

Other components contained in the second gas include, for example, inorganic gases such as nitrogen, oxygen, helium, argon, hydrogen, carbon monoxide, carbon dioxide, water, methane, ethane, propane, butane, pentane, acetylene, Hydrocarbon gases such as propylene, propadiene, butene and butadiene can be mentioned. At least one other component may be contained in the second gas, and two or more other components may be contained.

Next, a specific configuration of the zeolite membrane will be described.

A zeolite membrane is a membrane composed of zeolite, and may contain components other than zeolite. Components other than zeolite include, for example, silica and alumina. The zeolite membrane is formed by densely aggregating zeolite, and blocks permeation of components other than ethylene contained in the second gas. On the other hand, the zeolite membrane has fine pores (pores at the molecular level) due to the zeolite skeleton structure, and ethylene contained in the second gas permeates through the fine pores.

In the present invention, the zeolite constituting the zeolite membrane has alkali metal ions as counter ions. Alkali metal ions specifically include lithium ions (Li ⁺ ), sodium ions (Na ⁺ ), potassium ions (K ⁺ ), rubidium ions (Rb ⁺ ), cesium ions (Cs ⁺ ), francium ions (Fr ⁺ ). As a result, the zeolite membrane is less likely to deteriorate in ethylene separation performance even when exposed to the first gas containing the organochlorine compound, and can selectively permeate ethylene over a long period of time. In the separation method of the present invention, the zeolite counterion is preferably sodium ion. This allows ethylene to be separated more efficiently. In this specification, the counter ion of zeolite refers to the counter ion of the acid site of zeolite. The amount of alkali metal in the zeolite is not particularly limited, but the molar ratio of alkali metal/Al (molar ratio of alkali metal to aluminum) can be 0.01 to 1.00.

The zeolite membrane according to the present invention is preferably formed on a porous support. Here, "on the porous support" means the outer surface of the porous support (the surface of the porous support excluding the surface of the pores provided in the porous support) and the pores leading to the outside of the porous support. Apertures (pore openings exposed on the outer surface of the porous support). The zeolite membrane formed on the porous support covers the outer surface of the porous support and closes the pores leading to the outside of the porous support. In the zeolite membrane formed on the porous support, part of the zeolite membrane penetrates into the pores provided in the porous support and is formed on the surface of the pores (that is, on the inner surface). may be In addition, the zeolite membrane formed on the porous support may be formed on the entire area of the porous support, or may be formed only on a partial area of the porous support. .

The porous support is not particularly limited as long as it has strength to withstand pressure difference and heat resistance, and examples thereof include inorganic porous supports and inorganic-organic hybrid porous supports.

The inorganic porous support is not particularly limited as long as it is porous. A solid metal, glass, carbon molding, or the like can be used. The inorganic-organic hybrid porous support is not particularly limited, and examples thereof include those obtained by mixing or laminating the inorganic porous support and an organic support such as cellulose acetate. From the viewpoint of strength, heat resistance, and corrosion resistance, an inorganic porous support is preferred, and an alumina porous support made of alumina is more preferred.

The pore diameter of the surface layer of the porous support is preferably 0.05 μm or more and 3.00 μm or less, more preferably 0.10 μm or more and 2.00 μm or less. The pore diameter of the support can be evaluated by a bubble point method, a mercury intrusion method, or the like. The porous support surface layer refers to a support surface portion capable of forming a zeolite membrane. be. The pore diameter of the portion other than the surface layer of the support that forms the zeolite membrane is not particularly limited, but can be exemplified from 0.05 μm to 3.00 μm, preferably from 0.10 μm to 2.00 μm. In addition, since the porosity of the porous support influences the strength and permeation flow rate when ethylene is separated, the porous support preferably has a porosity of 20% or more and 60% or less.

The shape of the porous support is not limited as long as it can effectively separate ethylene. A columnar shape, a prismatic shape, a pyramidal shape, a truncated pyramidal shape, a columnar shape, a honeycomb shape having a large number of prismatic holes, and the like can be mentioned. Corrugated, tubular, cylindrical, conical, frustoconical, cylindrical, prismatic, prismatic, pyramidal, truncated pyramidal, or cylindrical porous supports are hollowed out at the center. A cylindrical shape is preferable, and the cylinder may be a penetrating one, or a test tube-like one that is not penetrating.

In the present invention, the zeolite constituting the zeolite membrane is preferably at least one zeolite selected from the group consisting of MFI-type zeolite, BEA-type zeolite, and FAU-type zeolite. This allows ethylene to be separated more efficiently. The crystal structure of zeolite can be confirmed by X-ray diffraction measurement (hereinafter referred to as "XRD"). The MFI type, BEA type, and FAU type are structural codes of zeolite crystals defined by the International Zeolite Society. ZSM-5, for example, is known as MFI type zeolite.

In the present invention, the zeolite membrane preferably has a Si/Al molar ratio (molar ratio of silicon to aluminum) of 1 to 1,000. In the case of MFI-type zeolite, the Si/Al molar ratio of the zeolite membrane is more preferably 5-100. This allows ethylene to be separated more efficiently.

Although the thickness of the zeolite membrane used in the present invention is not particularly limited, it is preferably 50 μm or less, more preferably 10 μm or less, in terms of easily improving ethylene permeability. The thickness is preferably 0.1 μm or more, more preferably 0.5 μm or more, from the viewpoint of easily improving ethylene selectivity and membrane strength.

Since the zeolite membrane can be manufactured by a known method, detailed description is omitted. Known methods include, for example, the methods described in JP-A-2017-213488, JP-A-2005-289735, and JP-A-2016-174996. As an example, seed crystals are attached to the outer surface of a base material, and the base material with the seed crystals attached is immersed in a raw material composition for zeolite membrane synthesis (solution containing zeolite constituents) for hydrothermal synthesis. can be mentioned. If a porous support is used as the substrate, the zeolite membrane can be formed on the porous support.

In the zeolite membrane obtained by the method described above, when the zeolite counter ion is an alkali metal ion, the zeolite membrane can be used in the separation method of the present invention. On the other hand, in the zeolite membrane obtained by the above-described method, when the counter ions of the zeolite are ions other than alkali metal ions, or when they are not the desired alkali metal ions, those ions are converted to the desired alkali metal ions. The zeolite membrane used in the separation method of the present invention can be obtained by ion exchange. The ion-exchange method is not particularly limited, but for example, a method of immersing the zeolite membrane in an aqueous solution containing alkali metal ions can be mentioned. The concentration of the alkali metal in the aqueous solution is not particularly limited, but can be, for example, 0.001 mol % or more and 1.00 mol % or less.

Next, a specific method for separating ethylene according to the present invention will be described.

The method for separating ethylene of the present invention has the separation steps described above. The zeolite membrane used in the separation step is a zeolite membrane whose counterions are alkali metal ions.

In the separation step, the second gas is brought into contact with the zeolite membrane exposed to the first gas.

The position at which the second gas contacts the zeolite membrane is not particularly limited, and the entire zeolite membrane may be contacted, or a partial region may be contacted. For example, the first gas can be brought into contact with only one of the surfaces of two zeolite membranes facing each other in the thickness direction. In this case, ethylene separated from the second gas permeates the zeolite membrane and is discharged from the other side.

When the zeolite membrane is formed on the porous support, the second gas is brought into contact with the zeolite membrane on the porous support in the separation step. Even when the zeolite membrane is formed on the porous support, the second gas may contact at least a partial region of the zeolite membrane. For example, when the porous support has two opposing surfaces (surfaces on the porous support) and a zeolite membrane is formed on at least one of the surfaces, the The second gas can be brought into contact with the zeolite membrane (its surface). In this case, ethylene separated from the second gas permeates the zeolite membrane and the porous support, and is discharged from the other side of the porous support.

In addition, in the zeolite membrane, the region in contact with the second gas may be the region exposed to the first gas or the region not exposed to the first gas.

Ethylene is separated from the second gas by contacting the second gas with the zeolite membrane. More specifically, when the zeolite membrane is brought into contact with the second gas, ethylene selectively permeates the zeolite membrane. That is, by performing the separation step, ethylene in the second gas selectively permeates the zeolite membrane and is separated from the second gas. At this time, other components such as nitrogen and carbon monoxide accompanying ethylene are blocked by the zeolite membrane, and the permeation amount is extremely small.

When hydrogen or carbon monoxide is contained as other components contained in the second gas, the separation in the present invention has a separation factor (−) represented by the following formula (1) of 2 or more, preferably 3 or more. can be performed using a zeolite membrane having

In the above formula (1), P _e indicates the molar concentration (mol%) of ethylene in the gas that has permeated the zeolite membrane, and P _o indicates the concentration of nitrogen (or carbon monoxide) in the gas that has permeated the zeolite membrane. _Se indicates the molar concentration (mol%) of ethylene in the second gas supplied to the zeolite membrane, and _So indicates the molar concentration (mol%) of nitrogen in the second gas supplied to the zeolite membrane ( or carbon monoxide).

In the separation method of the present invention, the ethylene permeability of the zeolite membrane is preferably 1.0×10 ⁻⁸ mol/m ² /s/Pa or more from the viewpoint of efficiently separating ethylene, and 3.0× It is more preferably 10 ⁻⁸ mol/m ² /s/Pa or more. In this specification, the permeability refers to the number of moles of gas (permeation flow rate) per unit time that passes through a zeolite membrane of a unit area with a unit partial pressure difference, and the permeation rate at a gas (ethylene) temperature of 20 ° C. degree. The permeability can be obtained based on a test conducted under conditions of a gas partial pressure difference of 0.2 MPa, a membrane area of 0.0006 m ² , and a membrane temperature of 20°C.

In the present invention, before separating ethylene from the second gas, a dehydration step (hereinafter also referred to as a "dehydration step") may be performed to previously remove moisture adsorbed by the zeolite membrane. By performing the dehydration step, ethylene can be separated with higher selectivity. Although the dehydration method in the dehydration step is not particularly limited, for example, a method of performing heat treatment at 500° C. or less under reduced pressure in order to improve the separation performance can be mentioned. The temperature is preferably 100° C. or higher, more preferably 50° C. or higher, in terms of low energy consumption. From the viewpoint of separation performance and energy consumption, the temperature is more preferably 50° C. or higher and 400° C. or lower. The dehydration in the dehydration step may be performed under reduced pressure, or may be performed under atmospheric pressure. Moreover, dehydration in the dehydration step may be performed in an oxygen atmosphere or in a non-oxygen atmosphere.

In the separation step, the method of bringing the second gas into contact with the zeolite membrane is not particularly limited, but for example, the second gas may be brought into contact with the temperature-controlled zeolite membrane. The temperature of the zeolite membrane is preferably −104° C. or higher, more preferably −20° C. or higher, further preferably 0° C. or higher. As a result, condensation of ethylene is suppressed in the pores of the zeolite membrane (in the pores of the porous support when a porous support is used), and separation can be performed with higher selectivity. Also, the temperature of the zeolite membrane is preferably 150° C. or lower, more preferably 100° C. or lower. Thereby, ethylene can be permeated more selectively.

Moreover, in the separation step, the pressure of the second gas contacting the zeolite membrane may be adjusted. The pressure of the second gas that contacts the zeolite membrane can be, for example, 0.1 MPa to 10 MPa.

In addition, the separation method of the present invention may include a recovery step (hereinafter also referred to as “recovery step”) for recovering ethylene separated by the zeolite membrane. In the recovery step, the method for recovering ethylene is not particularly limited, but usually, the ethylene separated by the zeolite membrane is deposited on the surface opposite to the surface in contact with the second gas (hereinafter also referred to as the “facing surface”). ). Therefore, for example, ethylene separated by the zeolite membrane can be recovered by arranging a recovery device on the opposite surface.

The zeolite membrane of the present invention can selectively separate ethylene from a second gas composed of multiple components without applying a large amount of heat energy from outside the system. In addition, since the zeolite membrane of the present invention has excellent durability against organochlorine compounds, it is possible to stably permeate and separate ethylene for a long period of time without deterioration of the zeolite membrane. Therefore, according to the separation method of the present invention, energy efficiency is extremely high compared to the conventional distillation method and the pressure swing adsorption method using an adsorbent, so an energy-saving production process can be provided.

EXAMPLES The present invention will be described below with reference to Examples, but the present invention is not limited to these Examples.

(X-ray diffraction measurement)
Using a general XRD device (device name: RINT Ultima III, manufactured by Rigaku Denki Co., Ltd.), the sample was subjected to XRD measurement. The measurement conditions were as follows.
Radiation source: CuKα rays (λ = 1.54 Å)
Measurement mode: step scan
Scanning conditions: 4° per minute
Divergence slit: 2/3deg
Scattering slit: 2/3deg
Receiving slit: 0.3mm
Step width: 0.02°
Measurement range: 2θ = 5 to 40°

(composition analysis)
Zeolite counterions and Si/Al molar ratios were measured and identified by energy dispersive X-ray spectroscopy (EDS). A general SEM-EDS device (device name: JSM-IT100 InTouchScope, manufactured by JEOL Ltd.) was used for measurement and identification.

(Ethylene separation evaluation)
The separation performance of the zeolite membrane was evaluated using the separation performance evaluation apparatus shown in FIG. In the evaluation of separation performance, as the second gas, a mixed gas having a molar ratio of ethylene/nitrogen of 20/80, or a mixed gas having a molar ratio of ethylene/hydrogen/carbon monoxide/carbon dioxide of 20/61/14/5 was used. The permeated gas that permeated the zeolite membrane was recovered with a sweep gas (He) and quantitatively analyzed by gas chromatography. A general gas chromatograph (device name: Agilent 7890B, manufactured by Agilent Technologies, Inc., TCD detector) was used for the measurement. A separation factor indicating ethylene separation performance was calculated by the above formula (1).

The evaluation device shown in FIG. 1 will be described in more detail. In the evaluation apparatus shown in FIG. 1, a mixed gas of ethylene gas 1 and other component gas 2 (nitrogen gas or a mixed gas of hydrogen, carbon monoxide and carbon dioxide) whose supply amounts are adjusted by mass flow controllers 4 and 5 was heated by a heater and supplied to the module 8 maintained at atmospheric pressure. The module 8 supplied the mixed gas to the outer surface of the cylindrical zeolite membrane-attached porous support 9 and discharged the permeated gas from the inner surface of the zeolite membrane-attached porous support 9 . The total supply amount of the mixed gas to be supplied was fixed at 100 ml/min, and the ratio of ethylene gas 1 and other component gas 2 was changed according to the example or the comparative example. The temperature of the zeolite membrane-attached porous support 9 (zeolite membrane) was changed by adjusting the temperature of the constant temperature bath 7 . On the permeation side, helium gas 3 was passed as a carrier gas at a rate of 100 mL/min. Collected gas containing the permeated gas that has permeated the zeolite membrane is fractionated and analyzed by the gas chromatograph 11 to calculate the permeation rate (mol/m ² /s/Pa) and the separation factor of the permeated gas that has permeated the zeolite membrane. and evaluated.

Reference example 1
A zeolite membrane composed of FAU-type zeolite was formed on a porous support in the same manner as in the patent document (Japanese Patent Application Laid-Open No. 2017-213488). XRD measurement was performed on the zeolite membrane portion of the obtained porous support. Identification of the constituent phases by XRD measurement confirmed that the crystalline phase (zeolite) was of the FAU type. Further, it was confirmed by SEM-EDS measurement that the counter ion of the zeolite membrane portion was Na and the Si/Al molar ratio was 1.2.

The resulting NaFAU-type zeolite membrane-attached porous support was mounted in the constant temperature bath of the evaluation apparatus shown in FIG. A mixed gas having a molar ratio of 20/61/14/5 was supplied to the surface of the zeolite membrane, and the ethylene separation performance was evaluated. Table 1 shows the ethylene permeability, CO permeability, and separation factor.

Example 1
The NaFAU-type zeolite membrane-attached porous support for which the ethylene separation performance was evaluated in Reference Example 1 was placed in a SUS closed container, where it was exposed to trichloromethane (CHCl ₃ ) vapor for 31 days (CHCl ₃ vapor pressure : 21 kPa, 20°C). Thereafter, the ethylene separation performance was evaluated under the same conditions as in Reference Example 1. Table 1 shows the ethylene permeability, CO permeability, and separation factor.

Reference example 2
A zeolite membrane composed of BEA-type zeolite was formed on a porous support with reference to the patent document (Japanese Patent Application Laid-Open No. 2005-289735). The constituent phases of the zeolite membrane portion of the obtained porous support were identified by XRD measurement, and it was confirmed that the crystal phase (zeolite) was the BEA type. Also, it was confirmed that the counter ion of the zeolite membrane portion was Na.

Ethylene separation performance evaluation was performed on the resulting NaBEA-type zeolite membrane-attached porous support under the same conditions as in Reference Example 1. Table 1 shows the ethylene permeability, CO permeability, and separation factor.

Example 2
The NaBEA-type zeolite membrane-attached porous support for which the ethylene separation performance was evaluated in Reference Example 2 was exposed to CHCl ₃ vapor in the same manner as in Example 1 for 32 days. Thereafter, the ethylene separation performance was evaluated under the same conditions as in Reference Example 1. Table 1 shows the ethylene permeability, CO permeability, and separation factor.

Reference example 3
A zeolite membrane composed of MFI-type zeolite was formed on a porous support with reference to the patent document (Japanese Patent Application Laid-Open No. 2016-174996). The constituent phases of the zeolite membrane portion of the obtained porous support were identified by XRD measurement, and it was confirmed that the crystalline phase (zeolite) was of the MFI type. Since the counter ion of the zeolite membrane portion was Na and the Si/Al molar ratio was 20, it was confirmed to be NaZSM-5 type zeolite.

The obtained porous support with NaZSM-5 type zeolite membrane was subjected to dehydration treatment (120° C., 2 h, N ₂ 50 mL/min), and then the temperature of the constant temperature bath was set to 40° C. The same as in Reference Example 1. Ethylene separation performance evaluation was performed under the following conditions. Table 1 shows the ethylene permeability, CO permeability, and separation factor. The reason why the NaZSM-5 type zeolite was dehydrated is to remove water adsorbed in the pores.

Example 3
The NaZSM-5 type zeolite membrane-attached porous support for which the ethylene separation performance was evaluated in Reference Example 3 was exposed to CHCl ₃ vapor in the same manner as in Example 1 for 30 days. Thereafter, the ethylene separation performance was evaluated under the same conditions as in Reference Example 1, except that the membrane temperature was 40°C. Table 1 shows the ethylene permeability, CO permeability, and separation factor.

Reference example 4
A porous support with an AgFAU-type zeolite membrane was obtained from a porous support with a NaFAU-type zeolite membrane prepared in the same manner as in Example 1 with reference to the patent document (Japanese Patent No. 6389625). Ethylene separation performance was evaluated under the same conditions as in Reference Example 1. Table 1 shows the ethylene permeability, CO permeability, and separation factor.

Comparative example 1
A porous support with a NaFAU-type zeolite membrane prepared in the same manner as in Reference Example 1 was immersed in a 0.01 mol % _AgNO3 aqueous solution for 2 hours and then washed with distilled water several times to obtain a porous support with an AgFAU-type zeolite membrane. A support was obtained. It was confirmed that the counter ion of the zeolite membrane portion was Ag. The membrane-coated porous support was exposed to CHCl ₃ vapor in the same manner as in Example 1 for 31 days. After that, under the same conditions as in Reference Example 1, the ethylene separation performance was evaluated. Table 1 shows the ethylene permeability, CO permeability, and separation factor.

From Table 1, it can be seen that when the counter ions in the zeolite membrane are alkali metal ions, the separation performance is maintained even after exposure to trichloromethane, which is an organochlorine compound. In addition, in Examples 1 to 3, the separation factor is greater than 1, and it can be seen that ethylene can be selectively separated from a mixed gas containing ethylene and CO even after exposure to an organic chlorine compound. In particular, in Examples 1 and 3, in which the FAU-type and ZSM-5-type zeolites are used, it can be seen that the ethylene permeability increases while maintaining the separation factor after exposure to trichloromethane.

Reference example 5
A porous support with a NaFAU-type zeolite membrane prepared in the same manner as in Reference Example 1 was immersed in a 0.1 mol % LiCl aqueous solution for 2 hours and then washed with distilled water several times to obtain a porous support with a LiFAU-type zeolite membrane. got a body The membrane-coated porous support is mounted in the constant temperature bath of the evaluation device shown in FIG. It was supplied to the zeolite membrane surface as follows, and the ethylene separation performance was evaluated. Ethylene permeabilities, nitrogen permeabilities, and separation factors are shown in Table 2.

Reference example 6
A NaFAU-type zeolite membrane-attached porous support prepared in the same manner as in Reference Example 1 was evaluated for ethylene separation performance under the same conditions as in Reference Example 5. Ethylene permeabilities, nitrogen permeabilities, and separation factors are shown in Table 2.

Reference example 7
A porous support with a NaFAU-type zeolite membrane prepared in the same manner as in Reference Example 1 was immersed in a 0.1 mol % KCl aqueous solution for 2 hours and then washed with distilled water several times to obtain a porous support with a KFAU-type zeolite membrane. got a body The membrane-coated porous support was evaluated for ethylene separation performance under the same conditions as in Reference Example 5. Ethylene permeabilities, nitrogen permeabilities, and separation factors are shown in Table 2.

Reference example 8
A porous support with a NaFAU-type zeolite membrane prepared in the same manner as in Reference Example 1 was immersed in a 0.1 mol % RbCl aqueous solution for 2 hours and then washed with distilled water several times to obtain a porous support with an RbFAU-type zeolite membrane. got a body The membrane-coated porous support was evaluated for ethylene separation performance under the same conditions as in Reference Example 5. Ethylene permeabilities, nitrogen permeabilities, and separation factors are shown in Table 2.

Reference example 9
A porous support with a NaFAU-type zeolite membrane prepared in the same manner as in Reference Example 1 was immersed in a 0.1 mol % CsCl aqueous solution for 2 hours and then washed with distilled water several times to obtain a porous support with a CsFAU-type zeolite membrane. got a body The membrane-coated porous support was evaluated for ethylene separation performance under the same conditions as in Reference Example 5. Ethylene permeabilities, nitrogen permeabilities, and separation factors are shown in Table 2.

Reference example 10
A porous support with a NaBEA-type zeolite membrane prepared in the same manner as in Reference Example 2 was evaluated for ethylene separation performance under the same conditions as in Reference Example 5, except that the temperature of the constant temperature bath was 60°C. Ethylene permeabilities, nitrogen permeabilities, and separation factors are shown in Table 2.

From Table 2, it can be seen that ethylene can be selectively separated from a mixed gas of ethylene and nitrogen when the counterions in the zeolite membrane are alkali metal ions.

Reference example 11
A porous support with a NaZSM-5 type zeolite membrane prepared in the same manner as in Reference Example 3 was immersed in a 0.1 mol% LiCl aqueous solution for 2 hours and then washed several times with distilled water to obtain LiZSM-5 type zeolite. A porous support with a membrane was obtained. The membrane-coated porous support was evaluated for ethylene separation performance under the same conditions as in Reference Example 1, except that the temperature of the constant temperature bath was 60°C. Ethylene permeability, CO permeability, and separation factor are shown in Table 3.

Reference example 12
Ethylene separation performance was evaluated under the same conditions as in Reference Example 11 for the NaZSM-5 type zeolite membrane-attached porous support prepared in the same manner as in Reference Example 3. Ethylene permeability, CO permeability, and separation factor are shown in Table 3.

Reference example 13
A porous support with a NaZSM-5 type zeolite membrane prepared in the same manner as in Reference Example 3 was immersed in a 0.1 mol% KCl aqueous solution for 2 hours, and then washed several times with distilled water to obtain a KZSM-5 type zeolite. A porous support with a membrane was obtained. The membrane-coated porous support was evaluated for ethylene separation performance under the same conditions as in Reference Example 11. Ethylene permeability, CO permeability, and separation factor are shown in Table 3.

Reference example 14
A NaZSM-5 type zeolite membrane-attached porous support prepared in the same manner as in Reference Example 3 was immersed in a 0.1 mol% RbCl aqueous solution for 2 hours and then washed several times with distilled water to obtain RbZSM-5 type zeolite. A porous support with a membrane was obtained. The membrane-coated porous support was evaluated for ethylene separation performance under the same conditions as in Reference Example 11. Ethylene permeability, CO permeability, and separation factor are shown in Table 3.

From Table 3, it can be seen that ethylene can be selectively separated from a mixed gas containing ethylene and CO when the counterions in the zeolite membrane are alkali metal ions.

According to the ethylene separation method of the present invention, it is possible to separate ethylene from a gas containing ethylene even after being exposed to a gas containing an organic chlorine compound.

1 Ethylene gas 2 Nitrogen gas or mixed gas of hydrogen / carbon monoxide / carbon dioxide 3 Helium 4 Mass flow controller 5 Mass flow controller 6 Mass flow controller 7 Thermostatic bath 8 Module 9 Porous support with zeolite membrane (filled part)
10 Exhaust 11 Gas Chromatograph 12 Exhaust

Claims (3)

Separation of ethylene using a zeolite membrane exposed to a first gas comprising an organochlorine compound, comprising:
contacting the zeolite membrane exposed to the first gas with a second gas composed of a plurality of components including ethylene;
The zeolite membrane is composed of zeolite whose counter ions are sodium ions ,
The zeolite is at least one zeolite selected from the group consisting of MFI-type zeolite, BEA-type zeolite, and FAU-type zeolite,
The organic chlorine compound is at least one selected from the group consisting of chloromethane, dichloromethane, trichloromethane, tetrachloromethane, chloroethane, dichloroethane, trichloroethane, tetrachloroethane, pentachloroethane, hexachloroethane, chloroethylene, dichloroethylene, trichlorethylene, and tetrachloroethylene. A method for separating ethylene, characterized in that it is a compound . 2. The method for separating ethylene according to claim 1, wherein said zeolite membrane is formed on an alumina porous support made of alumina. 3. The method for separating ethylene according to claim 1, wherein the zeolite membrane has a Si/Al molar ratio of 1 to 1,000.

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