A bifunctional catalyst, its preparation method and its use in ethylene purification

Abstract

The present application relates to a kind of bifunctional catalyst and its preparation method and application, the catalyst includes catalyst active component and carrier, the active component includes noble metal and non-noble metal, wherein noble metal active component is at least one of Pt, Pd, Ag, Ru and Rh.The non-noble metal active component is Mo and Ni.The catalyst provided by the present application can simultaneously remove acetylene and oxygen impurities in ethylene, wherein acetylene and hydrogen react to generate ethylene, and oxygen and hydrogen react to generate water and are removed.Compared with the catalyst for removing single impurity, the catalyst can reduce the investment of purification device, reduce production cost, and has obvious economic benefits.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of catalysis, more particularly to a bifunctional catalyst and its preparation method and application. BACKGROUND

[0002] Trace amounts of acetylene, carbon monoxide, oxygen, hydrogen, water, arsenide and other impurities in monomer ethylene can poison olefin polymerization catalysts, resulting in a decrease in catalyst activity and affecting normal operation of the device and quality of the polymerization product. In order to extend the life of the polymerization catalyst, trace amounts of impurities in monomer ethylene need to be removed.

[0003] The existing ethylene purification system functions are single, and the removal of various impurities needs to be carried out separately. The current acetylene removal technology for ethylene is mainly catalytic hydrogenation, and the catalyst is a noble metal palladium catalyst. This catalyst is easily poisoned and deactivated in the presence of carbon monoxide. The technology for removing oxygen from ethylene is mainly catalytic adsorption, and the catalyst used in this technology needs to be regenerated frequently.

[0004] Both of the above two purification catalysts need to be used separately, and there is currently no catalyst that can simultaneously remove both acetylene and oxygen impurities. SUMMARY

[0005] The removal of acetylene and oxygen from ethylene in existing industrial technology requires two catalysts, and the reaction is carried out in two reactors, which is relatively high in production cost and complex in process. In order to improve the purification efficiency of ethylene and reduce the production cost, the present application provides a bifunctional catalyst and its preparation method and application, which solves the above-mentioned problems existing in the prior art.

[0006] To achieve one of the above purposes, the technical solution adopted by the present application is as follows:

[0007] A bifunctional catalyst, comprising a catalyst active component and a carrier, the active component comprising a noble metal and a non-noble metal, wherein the noble metal active component is at least one of Pt, Pd, Ag, Ru and Rh. Preferably, Pd and / or Pt. The noble metal active component has a good effect on the removal of acetylene, but the effect on the removal of oxygen is not obvious. After adding the non-noble metal active components Mo and Ni, acetylene and oxygen impurities can be removed simultaneously, and the stability is very good.

[0008] Preferably, in the above technical solution, the non-noble metal active component is Mo and Ni.

[0009] In the technical solution, the carrier is at least one of alumina, silica, alumina-silica composite carrier or molecular sieve; preferably at least one of alumina, activated carbon, silica and alumina molecular sieve; further preferably alumina, the alumina carrier can be γ-Al2O3 and / or α-Al2O3, the shape can be spherical, strip, clover, column and the like, preferably spherical carrier. The advantage of the spherical carrier is that the pressure difference after the reactor is filled with catalyst is small.

[0010] In the technical solution, the content of the noble metal active component is 0.01-3 wt%, preferably 0.05-0.5 wt%.

[0011] Preferably, the noble metal active component source can be selected from one or more of Pt, Pd, Ag, Ru and Rh.

[0012] In the technical solution, the content of the non-noble metal active component Mo is 10-40 wt%, preferably 20-30 wt%; the content of the non-noble metal active component Ni is 1-20 wt%, preferably 5-10 wt%.

[0013] Preferably, the non-noble metal active component source can be selected from one or more of water-soluble metal oxides and metal salts. The metal salt can be one or more of nitrate, sulfate, chloride and acetate.

[0014] In the technical solution, the weight ratio of the noble metal active component and the non-noble metal active component of the catalyst is 1:(10-1000), preferably 1:(30-100).

[0015] In the technical solution, the weight ratio of the non-noble metal active components Mo and Ni is 1:(0.001-1000), preferably 1:(0.1-10).

[0016] In the technical solution, the carrier has the following physical properties: pore volume is 0.5-1.0 cm 3 / g.

[0017] Preferably, the pore size distribution is 1-20 nm.

[0018] Preferably, the average pore size is 3-9 nm.

[0019] Preferably, the specific surface area is 140-300 m 2 / g.

[0020] The second object of the present application is to provide a preparation method of the bifunctional catalyst, which comprises loading the active components onto a selected catalyst carrier and calcining to obtain the catalyst. The preparation method can be selected according to the prior art, for example, by impregnation or spraying method, and the noble metal active component and the non-noble metal active component can be loaded on the carrier respectively. The catalyst carrier loaded with the active components usually needs to be dried before calcination. The drying conditions are preferably 80-120℃ for 4-8 hours, and the calcination conditions are preferably 400-600℃ for 3-8 hours.

[0021] In the process of loading the active components onto the catalyst carrier, the active components are derived from metal compounds, preferably metal salts. The catalyst carrier is impregnated or sprayed after the active components are dissolved in water or organic solvents to form a solution. The concentration of the solution is not limited, as long as the active component compounds can be fully dissolved or the carrier can be fully impregnated or sprayed.

[0022] Specifically, the noble metal active component source can be selected from one or more of water-soluble palladium nitrate, silver nitrate, and palladium chloride. Preferably, one or more of palladium chloride and silver nitrate.

[0023] The non-noble metal active component source can be selected from one or more of water-soluble metal oxides, metal salts, etc. The metal salt can be one or more of nitrate, sulfate, chloride, and acetate. Preferably, one or more of molybdenum oxide and basic nickel carbonate.

[0024] The third object of the present application is to provide the application of the bifunctional catalyst in ethylene purification.

[0025] In the above technical solution, the content of acetylene in the ethylene gas is 1-20 ppm, and the content of oxygen is 1-100 ppm; preferably, the hydrogen-acetylene ratio is 4-100.

[0026] In the above technical solution, the catalyst can be used in a fixed bed reactor, and the reaction conditions are as follows: reaction temperature 30-250℃, reaction pressure 0.5-3 MPa, raw material space velocity 300-5000 h -1 , volume ratio of hydrogen to oxygen content in the raw material 4-100, acetylene content in the raw material 1-20 ppm, and oxygen content 1-100 ppm. Higher reaction temperature is beneficial to the deacetylene and deoxygenation reactions, so the reaction temperature can be adjusted at any time during the reaction according to the reaction results.

[0027] In the above technical solution, the catalyst needs to be reduced before use.

[0028] In the above technical solution, the catalyst reduction method comprises: contacting the catalyst with a mixed gas of hydrogen and nitrogen to reduce the catalyst, wherein the ratio of the mixed gas of hydrogen and nitrogen is 1 to 10, preferably 4 to 8. The reduction reaction temperature is 100 to 300°C, and the reduction reaction space velocity is 100 to 1000h- 1 , the reduction time is 5 to 20 hours.

[0029] The catalyst provided by the present invention can simultaneously remove acetylene and oxygen impurities from ethylene. Acetylene reacts with hydrogen to form ethylene, while oxygen reacts with hydrogen to form water, which is then removed. Compared with catalysts that remove a single impurity, this catalyst can reduce investment in purification equipment and production costs, offering significant economic benefits. Under the aforementioned reaction conditions, the catalyst can reduce acetylene in the feedstock from 2-20 ppm to below 1 ppm, and oxygen from 2-100 ppm to below 1 ppm, fully meeting the ethylene feedstock requirements of polyethylene plants and achieving significant economic benefits. DETAILED DESCRIPTION

[0030] The present invention will be described in detail below with reference to specific embodiments. It is necessary to point out that the following embodiments are only used to further illustrate the present invention and are not to be construed as limiting the scope of protection of the present invention. Non-essential improvements and adjustments made by those skilled in the art to the present invention based on the contents of the present invention still fall within the scope of protection of the present invention.

[0031] Various raw materials in the specific embodiments of the present invention are commercially available.

[0032] One of the objectives of the present invention is to provide a bifunctional catalyst comprising a catalyst active component and a support. The active component comprises a noble metal and a non-noble metal, wherein the noble metal active component is at least one of Pt, Pd, Ag, Ru, and Rh. Pd and / or Pt are preferred. The noble metal active component is highly effective in removing acetylene but less effective in removing oxygen. However, the addition of the non-noble metal active components Mo and Ni allows for the simultaneous removal of acetylene and oxygen impurities with excellent stability.

[0033] Preferably, in the above technical solution, the non-precious metal active components are Mo and Ni.

[0034] In a preferred embodiment of the above technology, the carrier is at least one of alumina, silica, an alumina-silica composite carrier, or a molecular sieve; preferably, at least one of alumina, activated carbon, silica, and alumina molecular sieve; more preferably, alumina. The alumina carrier may be γ-Al2O3 and / or α-Al2O3, and may be shaped like a sphere, a bar, a cloverleaf, or a column, with a spherical carrier being preferred. The advantage of a spherical carrier is that the pressure difference after the reactor is loaded with the catalyst is small.

[0035] In a preferred embodiment of the above-mentioned technology, the noble metal active component is present in an amount of 0.01 to 3 wt%, preferably 0.05 to 0.5 wt%.

[0036] In a preferred embodiment of the above-mentioned technology, the noble metal active component is selected from one or more of Pt, Pd, Ag, Ru and Rh.

[0037] In a preferred embodiment of the above-mentioned technology, the non-noble metal active component Mo is present in an amount of 10 to 40 wt%, preferably 20 to 30 wt%; the non-noble metal active component Ni is present in an amount of 1 to 20 wt%, preferably 5 to 10 wt%.

[0038] In a preferred embodiment of the above-mentioned technology, the non-noble metal active component is selected from one or more of water-soluble metal oxides and metal salts, wherein the metal salt is selected from one or more of nitrate, sulfate, chloride and acetate.

[0039] In a preferred embodiment of the above-mentioned technology, the weight ratio of the noble metal active component to the non-noble metal active component is 1:(10 to 1000), preferably 1:(30 to 100).

[0040] In a preferred embodiment of the above-mentioned technology, the weight ratio of the non-noble metal active component Mo to the non-noble metal active component Ni is 1:(0.001 to 1000), preferably 1:(0.1 to 10).

[0041] In a preferred embodiment of the above-mentioned technology, the support has the following physical properties: pore volume of 0.5 to 1.0 cm 3 / g.

[0042] Preferably, the pore size distribution is 1 to 20 nm.

[0043] Preferably, the average pore size is 3 to 9 nm.

[0044] Preferably, the specific surface area is 140 to 300 m 2 / g.

[0045] The second object of the present application is to provide a preparation method of the bifunctional catalyst, which comprises loading the active component onto a selected catalyst support, and calcining to obtain the catalyst. The preparation method can be selected according to the prior art, for example, by impregnation or spraying method, or the noble metal active component and the non-noble metal active component can be loaded on the support respectively. Before calcination, the catalyst support loaded with the active component usually needs to be dried. The drying conditions are preferably 80-120°C for 4-8 hours; the calcination conditions are preferably 400-600°C for 3-8 hours.

[0046] When loading the active component onto the catalyst support, the active component is derived from a metal compound, preferably a metal salt. This metal compound is dissolved in water or an organic solvent to form a solution, which is then impregnated or sprayed onto the catalyst support. The concentration of the solution is not limited, as long as it can sufficiently dissolve the active component compound or sufficiently impregnate or spray the support.

[0047] Specifically, the source of the noble metal active component can be selected from one or more of water-soluble palladium nitrate, silver nitrate, and palladium chloride, preferably one or more of palladium chloride and silver nitrate.

[0048] The non-precious metal active component can be selected from one or more water-soluble metal oxides, metal salts, etc. The metal salts can be one or more of nitrates, sulfates, chlorides, and acetates. Preferably, one or more of molybdenum oxide and basic nickel carbonate are used.

[0049] A third object of the present invention is to provide an application of a bifunctional catalyst in ethylene purification.

[0050] In a preferred embodiment of the above technology, the acetylene content in the ethylene gas is 1-20 ppm, and the oxygen content is 1-100 ppm; preferably, the hydrogen-to-acetylene ratio is 4-100.

[0051] In a preferred embodiment of the above technology, the catalyst can be used in a fixed bed reactor under the following reaction conditions: reaction temperature 30-250°C, reaction pressure 0.5-3 MPa, raw material space velocity 300-5000h -1 The volume ratio of hydrogen to oxygen in the raw material is 4-100, the acetylene content in the raw material is 1-20 ppm, and the oxygen content is 1-100 ppm. Increasing the reaction temperature is beneficial to the deacetylation and deoxygenation reactions. Therefore, during the reaction process, the reaction temperature is adjusted according to the reaction results.

[0052] In a preferred embodiment of the above technology, the catalyst needs to be reduced before use.

[0053] In a preferred embodiment of the above technology, the catalyst reduction method comprises: contacting a mixed gas of hydrogen and nitrogen with the catalyst to reduce the catalyst, wherein the ratio of the mixed gas of hydrogen and nitrogen is 1 to 10, preferably 4 to 8. The reduction reaction temperature is 100 to 300°C, and the reduction reaction space velocity is 100 to 1000h- 1 , the reduction time is 5 to 20 hours.

[0054] The catalyst provided by the present invention can simultaneously remove acetylene and oxygen impurities from ethylene. Acetylene reacts with hydrogen to form ethylene, while oxygen reacts with hydrogen to form water, which is then removed. Compared with catalysts that remove a single impurity, this catalyst can reduce investment in purification equipment and production costs, offering significant economic benefits. Under the aforementioned reaction conditions, the catalyst can reduce acetylene in the feedstock from 2-20 ppm to below 1 ppm, and oxygen from 2-100 ppm to below 1 ppm, fully meeting the ethylene feedstock requirements of polyethylene plants and achieving significant economic benefits.

[0055] Example 1

[0056] (1) Use γ-Al2O3 balls as the carrier (the pore volume of the carrier is 0.8cm 3 / g, pore size distribution is 10nm, average pore size is 6nm, and specific surface area is 220m 2 / g).

[0057] (2) Preparation of impregnation solution: Weigh 12 g of molybdenum trioxide and 5 g of basic nickel carbonate and dissolve them in water to prepare the first impregnation solution. Measure 30 ml of palladium chloride solution with a concentration of 55 mg / ml to prepare the second impregnation solution.

[0058] (3) Catalyst preparation: The carrier was impregnated with the first impregnation solution using an equal volume impregnation method. After uniform impregnation, the carrier was dried at 80°C for 2 hours and at 120°C for 4 hours. The dried catalyst was then impregnated with the second impregnation solution using an equal volume impregnation method. The catalyst was dried using the same method as above and calcined at 600°C for 4 hours. The obtained catalyst was numbered A1, wherein the palladium content was 0.2% by weight, the molybdenum content was 20% by weight, and the nickel content was 5% based on the weight of the catalyst.

[0059] (4) Catalyst evaluation: The catalyst was tested for deacetylation and deoxygenation performance in a conventional small-scale fixed-bed reactor. The catalyst loading was 10 ml. A feed gas containing acetylene and oxygen was introduced at 30-150°C for reaction. The feed gas was ethylene and 1000 ppm of hydrogen was added. The acetylene content in the feed gas was 20 ppm and the oxygen content was 100 ppm. The gas feed space velocity was 3000 h-100. 1 , reaction pressure 1.0MPa, after catalyst reaction, the acetylene content in the output is less than 1ppm, and the oxygen content is less than 1ppm.

[0060] Example 2

[0061] The catalyst was prepared according to the method described in Reference Example 1, except that in step (2), the impregnation solution was prepared as follows: 18 g of molybdenum trioxide and 10 g of basic nickel carbonate were weighed and dissolved in water to prepare a first impregnation solution, and 18 ml of a palladium chloride solution having a concentration of 55 mg / ml was measured to prepare a second impregnation solution, and the rest was the same as in Reference Example 1. The finally prepared catalyst was designated as A2, wherein the content of palladium was 0.12 wt%, the content of molybdenum was 30 wt%, and the content of nickel was 10 wt% based on the total weight of the catalyst.

[0062] Example 3

[0063] The catalyst was prepared according to the method described in Reference Example 1, except that in step (2), the impregnation solution was prepared as follows: 9 g of molybdenum trioxide and 5 g of basic nickel carbonate were weighed and dissolved in water to prepare a first impregnation solution, and 12 ml of a palladium chloride solution having a concentration of 55 mg / ml was measured to prepare a second impregnation solution, and the rest was the same as in Reference Example 1. The finally prepared catalyst was designated as A3, wherein the content of palladium was 0.08 wt%, the content of molybdenum was 15 wt%, and the content of nickel was 5 wt% based on the total weight of the catalyst.

[0064] Example 4

[0065] The catalyst was prepared according to the method described in Reference Example 1, except that in step (2), the impregnation solution was prepared as follows: 9 g of molybdenum trioxide and 5 g of basic nickel carbonate were weighed and dissolved in water to prepare a first impregnation solution, and 6 ml of a palladium chloride solution having a concentration of 55 mg / ml was measured to prepare a second impregnation solution, and the rest was the same as in Reference Example 1. The finally prepared catalyst was designated as A4, wherein the content of palladium was 0.04 wt%, the content of molybdenum was 15 wt%, and the content of nickel was 5 wt% based on the total weight of the catalyst.

[0066] Example 5

[0067] The catalyst was prepared according to the method described in Reference Example 1, except that in step (2), the impregnation solution was prepared as follows: 6 g of molybdenum trioxide and 5 g of basic nickel carbonate were weighed and dissolved in water to prepare a first impregnation solution, and 18 ml of a palladium chloride solution having a concentration of 55 mg / ml was measured to prepare a second impregnation solution, and the rest was the same as in Reference Example 1. The finally prepared catalyst was designated as A5, wherein the content of palladium was 0.12 wt%, the content of molybdenum was 10 wt%, and the content of nickel was 5 wt% based on the total weight of the catalyst.

[0068] Example 6

[0069] A catalyst was prepared according to the method described in Example 1, except that in step (2), an impregnation solution was prepared by weighing 6 g of molybdenum trioxide and 5 g of basic nickel carbonate and dissolving them in water to prepare a first impregnation solution, and adding 45 ml of a palladium chloride solution having a concentration of 55 mg / ml to prepare a second impregnation solution. The remaining steps were the same as in Example 1. The resulting catalyst was designated A6, wherein the palladium content was 0.3% by weight, the molybdenum content was 10% by weight, and the nickel content was 5% by weight, based on the total weight of the catalyst.

[0070] Example 7

[0071] A catalyst was prepared according to the method described in Example 1, except that in step (2), an impregnation solution was prepared by weighing 3 g of molybdenum trioxide and 5 g of basic nickel carbonate and dissolving them in water to prepare a first impregnation solution, and adding 30 ml of palladium chloride solution having a concentration of 55 mg / ml to prepare a second impregnation solution. The remaining steps were the same as in Example 1. The resulting catalyst was designated A7, wherein the palladium content was 0.2% by weight, the molybdenum content was 5% by weight, and the nickel content was 5% by weight, based on the total weight of the catalyst.

[0072] Example 8

[0073] The preparation method described in Example 1 was used, except that in step (2), the impregnation solution was prepared by weighing 18 g of molybdenum trioxide and 10 g of basic nickel carbonate and dissolving them in water to prepare a first impregnation solution, and weighing 0.5 g of silver nitrate and dissolving it in water to prepare a second impregnation solution. The remaining steps were the same as in Example 1. The resulting catalyst was designated A8, wherein, based on the total weight of the catalyst, the silver content was 1% by weight, the molybdenum content was 30% by weight, and the nickel content was 10% by weight.

[0074] Example 9

[0075] A catalyst was prepared according to the method described in Example 1, except that in step (2), an impregnation solution was prepared by weighing 18 g of molybdenum trioxide and 0.1 g of basic nickel carbonate and dissolving them in water to prepare a first impregnation solution, and adding 18 ml of palladium chloride solution having a concentration of 55 mg / ml to prepare a second impregnation solution. The remaining steps were the same as in Example 1. The resulting catalyst was designated A2, wherein, based on the total weight of the catalyst, the palladium content was 0.12% by weight, the molybdenum content was 30% by weight, and the nickel content was 0.1% by weight.

[0076] Example 10

[0077] The catalyst was prepared according to the method described in Reference Example 1, except that in step (2), the impregnation solution was prepared by weighing 0.1 g of molybdenum trioxide and 20 g of basic nickel carbonate into water. Then, 18 ml of a palladium chloride solution having a concentration of 55 mg / ml was measured, and the second impregnation solution was prepared. The remaining steps were the same as in Reference Example 1. The finally obtained catalyst was designated as A2, wherein the content of palladium was 0.12 wt%, the content of molybdenum was 0.15 wt%, and the content of nickel was 20 wt% based on the total weight of the catalyst.

[0078] Comparative Example 1

[0079] The catalyst was prepared according to the method described in Reference Example 1, except that in step (2), only one impregnation solution was prepared by measuring 30 ml of a palladium chloride solution having a concentration of 55 mg / ml. The remaining steps were the same as in Reference Example 1. The finally obtained catalyst was designated as Dl, wherein the content of palladium was 0.2 wt% based on the total weight of the catalyst.

[0080] Comparative Example 2

[0081] The catalyst was prepared according to the method described in Reference Example 1, except that in step (2), only one impregnation solution was prepared by weighing 12 g of molybdenum trioxide into water. The remaining steps were the same as in Reference Example 1. The finally obtained catalyst was designated as D2, wherein the content of molybdenum was 20 wt% based on the total weight of the catalyst.

[0082] Comparative Example 3

[0083] The catalyst was prepared according to the method described in Reference Example 1, except that in step (2), only one impregnation solution was prepared by weighing 5 g of basic nickel carbonate into water. The remaining steps were the same as in Reference Example 1. The finally obtained catalyst was designated as D3, wherein the content of nickel was 5 wt% based on the total weight of the catalyst.

[0084] Comparative Example 4

[0085] The catalyst was prepared according to the method described in Reference Example 1, except that in step (2), only one impregnation solution was prepared by weighing 12 g of molybdenum trioxide and 5 g of basic nickel carbonate into water. The remaining steps were the same as in Reference Example 1. The finally obtained catalyst was designated as D4, wherein the content of molybdenum was 20 wt% and the content of nickel was 5 wt% based on the total weight of the catalyst.

[0086] Table 1 Results of de-alkylation and de-oxygenation reactions of the catalysts of each example after reduction

[0087]

[0088]

[0089] From the results in Table 1, it can be seen that the catalysts of the present application have better de-acetylation and de-oxygenation effects than the catalysts described in Comparative Examples 1-3. The data in Table 2 are for the fresh catalyst of Example 1 after 500 hours and more, and the stability of the catalysts is investigated. The catalysts of the present application exhibit ideal stability.

[0090] Table 2 Stability test data

[0091]

Claims

1. A bifunctional catalyst for simultaneously removing acetylene and oxygen impurities from ethylene, comprising a catalyst active component and a support, wherein the active component comprises a noble metal and a non-noble metal, wherein the noble metal active component is at least one of Pt, Pd, Ag, Ru, and Rh; The non-precious metal active components are Mo and Ni; The content of the noble metal active component is 0.01 to 3 weight %; The content of the non-precious metal active component Mo is 10 to 40 weight %; The content of the non-precious metal active component Ni is 1 to 20 weight %; The weight ratio of the noble metal active component to the non-noble metal active component of the catalyst is 1:(10-1000); The weight ratio of the non-precious metal active components Mo and Ni is 1: (0.01-100); The carrier has the following physical properties: Pore ​​volume is 0.5~1.0cm 3 / g; The pore size distribution is 1 to 20 nm; The average pore size is 3 to 9 nm; Specific surface area is 140~300m 2 / g.

2. The catalyst according to claim 1, characterized in that The noble metal active component is Pd and / or Pt; or / and, The carrier is at least one of alumina, silica, alumina-silica composite carrier or alumina molecular sieve.

3. The catalyst according to claim 1, characterized in that The content of the noble metal active component is 0.05 to 0.5 weight %.

4. The catalyst according to claim 1, characterized in that The content of the non-precious metal active component Mo is 20-30 weight %; the content of the non-precious metal active component Ni is 5-10 weight %.

5. The catalyst according to claim 1, characterized in that The weight ratio of the noble metal active component to the non-noble metal active component of the catalyst is 1:(30-100).

6. The catalyst according to claim 1, characterized in that The weight ratio of the non-noble metal active components Mo and Ni is 1:(0.1-2).

7. A method for preparing the bifunctional catalyst according to any one of claims 1 to 6, comprising loading the active component onto a selected catalyst carrier and calcining to obtain the catalyst.

8. Use of the bifunctional catalyst according to any one of claims 1 to 6 or the bifunctional catalyst prepared according to claim 7 in ethylene purification.

9. The use according to claim 8, wherein the acetylene content in the ethylene gas is 1-20 ppm, and the oxygen content is 1-100 ppm.

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