A separation adsorbent and a method for concentrating ethylene

Abstract

A separation adsorbent characterized by comprising a modified A-type molecular sieve and a carrier, wherein the modified A-type molecular sieve comprises an A-type molecular sieve and a metal salt active component, wherein the metal salt active component comprises a component L1 selected from a metal salt containing at least one of Mg 2+ , Ca 2+ , and Sr 2+ , and a component L2 selected from a metal salt containing at least one of Cr 3+ , Cu 2+ , Zn 2+ , and Mn 2+ . The adsorbent has improved ethylene adsorption capacity and adsorption selectivity.

Description

Technical Field

[0001] This application relates to the field of adsorption separation, specifically to a separation adsorbent, its preparation method, and its method for concentrating ethylene from a mixture of ethylene and ethane. Background Technology

[0002] Ethylene is a crucial basic chemical raw material and a vital bridge between oil and chemical industries, with its production, apparent consumption, and demand increasing year by year. In many ethylene production processes, after gas separation, ethylene and ethane coexist. This is because the physicochemical properties of ethylene and ethane are quite similar, making separation difficult. Currently, the commonly used method in industry is cryogenic distillation. This method requires high pressure (0.7-2.8 MPa), extremely low temperature (-160℃), and distillation columns with multiple trays (>100) and high reflux ratios (2.5-4), resulting in high energy consumption, large investment, and complex operation. Therefore, there is an urgent need to develop efficient, energy-saving, and environmentally friendly methods for concentrating ethylene.

[0003] Currently, molecular sieves or porous adsorbents are used to separate ethylene and ethane at room temperature and pressure, but these methods suffer from drawbacks such as low adsorption capacity, low selectivity, and poor stability. For example, NaY molecular sieve has an adsorption capacity of 2.1 mmol / g for ethylene at room temperature and pressure, but its ethylene / ethane separation selectivity is only 1.4 (AICHE Journal, 1995, 41(3): 509-517). The all-silica molecular sieve ITQ-55 achieves ethylene / ethane separation through the kinetic difference in diffusion between ethylene and ethane, but its adsorption capacity for ethylene at room temperature and pressure is only 1.3 mmol / g (Science, 2017, 358: 1068-1071). In addition to using the aforementioned unmodified molecular sieve materials, there are also adsorbents based on transition metal ions, such as AgA molecular sieves (Journal of the American Chemical Society, 2012, 134(36): 14635-14637), organic porous materials PAF-1-SO3Ag (Journal of the American Chemical Society, 2014, 136(24): 8654-8660), and CuCl supported alumina (CN1048010C), which selectively adsorb ethylene through metal π-complexation. However, these adsorbents are easily contaminated by water, oxygen, reducing gases, and sulfur-containing compounds in the raw gas, have poor stability, are prone to deactivation, and have a short service life, making them unsuitable for industrial applications. Summary of the Invention

[0004] The purpose of this application is to address the problems existing in the prior art by providing a separation adsorbent with improved ethylene adsorption capacity and selectivity, good stability, and low susceptibility to environmental gases during use. It also provides a method for concentrating ethylene using this separation adsorbent at lower temperatures and pressures. This method is simple to operate, has low energy consumption and low operating costs, and has strong prospects for industrial application.

[0005] To achieve the above objectives, a first aspect of this application provides a separation adsorbent, characterized in that it comprises 90-97 wt% of a modified type A molecular sieve and 3-10 wt% of a support, wherein the modified type A molecular sieve comprises a type A molecular sieve and a metal salt active component, wherein the metal salt active component comprises component L1 and component L2, and component L1 is selected from Mg-containing... 2+ Ca 2+ and Sr 2+ At least one of the metal salts, wherein component L2 is selected from Cr-containing metals. 3+ Cu 2+ Zn 2+ and Mn 2+ At least one of the metal salts; based on modified type A molecular sieve, wherein the type A molecular sieve is 75.0-95.0 wt%, the active metal salt component is 5.0-25.0 wt%, component L1 is 0.9-21.0 wt%, and component L2 is 1.5-7.0 wt%.

[0006] In some embodiments, based on modified type A molecular sieves, component L1 is 4.5-16.0 wt% and component L2 is 2.0-6.5 wt%.

[0007] In some embodiments, the modified type A molecular sieve has an average grain size of not more than 1 μm, preferably not more than 0.9 μm, and more preferably 0.70-0.85 μm.

[0008] In some embodiments, the carrier in the ethylene ethane separation adsorbent is at least one selected from kaolin, bentonite, montmorillonite, diatomite, rettoite, and halloysite.

[0009] In some embodiments, the ethylene ethane separation adsorbent is a molded microsphere with a particle size of 0.3-0.6 mm.

[0010] The separation adsorbent of this application comprises a modified type A molecular sieve with small crystal size and active components of L1 and L2 bimetallic salts, which has improved ethylene adsorption capacity and adsorption selectivity, and good stability, and is not easily affected by ambient gases during use.

[0011] The separation adsorbent of the first aspect of this application is obtained by mixing a modified type A molecular sieve with a support and then rolling it into balls.

[0012] The modified type A molecular sieve is obtained by preparing type A molecular sieve and then modifying it by ion exchange.

[0013] In some embodiments, the preparation of the type A molecular sieve may include the following steps:

[0014] (1) The raw materials sodium hydroxide, aluminum source, silicon source and deionized water are mixed evenly according to the molar ratio of Na2O:Al2O3:SiO2:H2O of 2.5-4.0:0.8-1.0:1.9-3.8:100-150 to obtain a mixed gel;

[0015] (2) The mixed gel from step (1) is aged at a temperature of 25-40°C for 4-120 h, preferably 12-72 h, to obtain the initial reaction mixture;

[0016] (3) The initial reaction mixture of step (2) is crystallized under hydrothermal reaction conditions at a temperature of 50-90℃, preferably 60-80℃, for 2-12 hours, preferably 4-10 hours. After filtration, washing and drying, type A molecular sieve is obtained.

[0017] In some embodiments, the ion exchange modification may be, but is not limited to, one of the following processes: process one, process two, and process three.

[0018] The ion exchange modification process includes the following steps:

[0019] (1) The soluble salt containing component L1 is mixed with type A molecular sieve and deionized water at a mass ratio of 0.4-2.5:1:5-20, and the mixture is exchanged at a temperature of 50-90℃, preferably 60-80℃, for 30-120 min, preferably 60-100 min. Then the mixture is filtered, washed and dried.

[0020] (2) The soluble salt containing component L2 is mixed with the product of step (1) and deionized water at a mass ratio of 0.05-0.28:1:5-20, and the mixture is exchanged at a temperature of 50-90℃, preferably 60-80℃, for 30-120 min, preferably 60-100 min. Then the mixture is filtered, washed and dried.

[0021] The second ion exchange modification process includes the following steps:

[0022] (1) Mix the soluble salt containing component L2 with type A molecular sieve and deionized water at a mass ratio of 0.05-0.28:1:5-20, exchange at a temperature of 50-90℃, preferably 60-80℃ for 30-120 min, preferably 60-100 min, and then filter, wash and dry.

[0023] (2) The soluble salt containing component L1 is mixed with the product of step (1) and deionized water at a mass ratio of 0.4-2.5:1:5-20, and the mixture is exchanged at a temperature of 50-90℃, preferably 60-80℃, for 30-120 min, preferably 60-100 min. Then the mixture is filtered, washed and dried.

[0024] The ion exchange modification process includes: mixing soluble salts containing component L1 and soluble salts containing component L2 with type A molecular sieves and deionized water at a mass ratio of 0.4-2.5:0.05-0.28:1:5-20, exchanging the mixture at a temperature of 50-90℃, preferably 60-80℃, for 30-120 min, preferably 60-100 min, followed by filtration, washing, and drying.

[0025] The soluble salt containing component L1 is selected from Mg. 2+ Ca 2+ and Sr 2+ At least one of the nitrates or chlorides, wherein the soluble salt containing component L2 is selected from Cr 3+ Cu 2+ Zn 2+ and Mn 2+ At least one of the following: nitrate or chloride.

[0026] A second aspect of this application provides a method for concentrating ethylene, characterized by comprising the steps of selectively adsorbing a mixture of ethylene and ethane under adsorption conditions with a separation adsorbent; and desorbing ethylene from the adsorbent under desorption conditions; wherein the adsorbent is selected from the separation adsorbent provided in the first aspect of this application.

[0027] In some embodiments, the adsorption conditions include an adsorption temperature of 10-40°C and an adsorption pressure of 0.5-1.0 MPa, preferably 0.6-0.8 MPa.

[0028] In some embodiments, the desorption conditions include a desorption temperature of 80-200°C and a desorption pressure of 0.001-0.1 MPa, preferably 0.005-0.08 MPa.

[0029] In some embodiments, the adsorbent is activated and then contacted with a mixture of ethylene and ethane. The activation is performed by treating the adsorbent in a nitrogen, argon, or helium atmosphere at a temperature of 150-450°C, preferably 200-400°C, for 30-180 minutes, preferably 60-150 minutes.

[0030] In some embodiments, the selective adsorption is carried out in a fixed bed or a moving bed; the mass hourly space velocity (MSV) of the ethylene and ethane mixture is 0.3-3 h⁻¹. -1 .

[0031] The method for concentrating ethylene provided in this application can separate high-concentration ethylene gas from a mixture of ethylene and ethane at lower temperatures and pressures. This method has a simple operation process, low industrial operating costs, and low energy consumption, and has strong prospects for industrial application. Attached Figure Description

[0032] Figure 1 This is a scanning electron microscope image of the modified type A molecular sieve in Example 1 of this application. Detailed Implementation

[0033] The following details the separation adsorbent of this application, its preparation method, and the method for using the separation adsorbent to concentrate ethylene. However, unnecessary details may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0034] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0035] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0036] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0037] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0038] Unless otherwise specified, the term "or" is inclusive in this application. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, the condition "A or B" is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0039] Adsorption separation utilizes adsorbents to separate ethylene and ethane at room temperature and pressure. It offers advantages such as low energy consumption, low cost, and simple operation, making it a promising candidate for industrial applications. The core of adsorption separation is the adsorbent; an ideal adsorbent should possess characteristics such as high adsorption capacity, high selectivity, and long service life.

[0040] The first aspect of this application provides a separation adsorbent, characterized in that it comprises 90-97 wt% of a modified type A molecular sieve and 3-10 wt% of a support, wherein the modified type A molecular sieve comprises a type A molecular sieve and a metal salt active component, wherein the metal salt active component comprises component L1 and component L2, and component L1 is selected from Mg-containing... 2+ Ca 2+ and Sr 2+ At least one of the metal salts, wherein component L2 is selected from Cr-containing metals. 3+ Cu 2+ Zn 2+ and Mn 2+ At least one of the metal salts; based on modified type A molecular sieve, wherein the type A molecular sieve is 75.0-95.0 wt%, the active metal salt component is 5.0-25.0 wt%, component L1 is 0.9-21.0 wt%, and component L2 is 1.5-7.0 wt%.

[0041] In some embodiments, based on the modified type A molecular sieve, component L1 is 0.9-21.0 wt%, and component L2 is 1.5-7.0 wt%. Preferably, component L1 is 4.5-16.0 wt%, and component L2 is 2.0-6.5 wt%. In this application, the loading amounts of components L1 and L2 are obtained by X-ray fluorescence spectroscopy. For example, it can be determined using a Rigaku ZSX100E X-ray fluorescence spectrometer with a tube voltage of 40 kV and a tube current of 250 mA, utilizing the relationship that the intensity of each element's fluorescence rays is proportional to its concentration for elemental analysis. For example, in one embodiment, the loading amount of component L1 in the modified type A molecular sieve is 10.14 wt%, and the loading amount of component L2 is 5.08 wt%.

[0042] In some embodiments, the modified type A molecular sieve has an average grain size of no more than 1.0 μm, preferably no more than 0.9 μm, and more preferably 0.70-0.85 μm. In this application, the average grain size of the modified type A molecular sieve is obtained by observation and statistical analysis using a scanning electron microscope (SEM). For example, it can be measured using a Hitachi S4800 SEM from Japan, with an accelerating voltage of 5 kV, a working distance of 8 mm, and a magnification of 5 k to 50 k. The size of each grain is measured according to the scale bar on the image, and at least 100 grains are measured and then statistically analyzed. For example, in one embodiment, the average grain size of the modified type A molecular sieve is 711 nm.

[0043] In some embodiments, the carrier is at least one of kaolin, bentonite, montmorillonite, diatomite, rettoite, and halloysite.

[0044] In some embodiments, the ethylene ethane separation adsorbent of this application is preferably a molded microsphere with a particle size of 0.3-0.6 mm.

[0045] This application also discloses a method for preparing the ethylene ethane separation adsorbent of the first aspect mentioned above, which involves mixing a modified type A molecular sieve with a support and then rolling it into spheres. For example, the method includes uniformly mixing the modified type A molecular sieve with the support to form a mixed powder, placing it in a sugar-coating pan, and simultaneously rolling it while spraying in a certain proportion, for example, 12 wt%, of deionized water based on the weight of the mixed powder, and then rolling it into spheres with a particle size of 0.3-0.6 mm.

[0046] In some embodiments, the modified type A molecular sieve in the ethylene ethane separation adsorbent is obtained by first preparing a type A molecular sieve and then modifying the type A molecular sieve by ion exchange.

[0047] In some embodiments, the preparation of type A molecular sieves includes the following steps:

[0048] (1) Mix the raw materials sodium hydroxide, aluminum source, silicon source and deionized water in a molar ratio of Na2O:Al2O3:SiO2:H2O of 2.5-4.0:0.8-1.0:1.9-3.8:100-150 to obtain a mixed gel;

[0049] (2) The mixed gel from step (1) is aged at a temperature of 25-40°C for 4-120 h, preferably 12-72 h, to obtain the initial reaction mixture;

[0050] (3) Crystallize the initial reaction mixture of step (2) under hydrothermal reaction conditions at a temperature of 50-90℃, preferably 60-80℃, for 2-12 hours, preferably 4-10 hours. After filtration, washing and drying, type A molecular sieve is obtained.

[0051] In step (1), the aluminum source is at least one selected from aluminum salts, aluminates, aluminum oxides, aluminum hydroxides, and aluminum alkoxy, preferably aluminates or aluminum hydroxides, wherein the aluminate is sodium aluminate, and the aluminum hydroxide is pseudoboehmite or boehmite; the silicon source is at least one selected from silica, silica sol, silica gel, water glass, activated silica, and tetraethyl orthosilicate, preferably silica sol, water glass, or tetraethyl orthosilicate.

[0052] In step (2), the mixed gel from step (1) is aged to obtain an initial reaction mixture. The aging temperature is 25-40℃ and the aging time is 4-120h, preferably 12-72h.

[0053] In step (3), the initial reaction mixture from step (2) is crystallized in a hydrothermal reactor at a temperature of 50-90°C, preferably 60-80°C, for a time of 2-12 hours, preferably 4-10 hours. After filtration and washing, type A molecular sieve is obtained.

[0054] In some embodiments, the further modification of the type A molecular sieve by ion exchange can be carried out through one of the following three processes, but is not limited to.

[0055] Process 1:

[0056] (1) The soluble salt containing component L1 is mixed with type A molecular sieve and deionized water at a mass ratio of 0.4-2.5:1:5-20, and the mixture is exchanged at a temperature of 50-90℃, preferably 60-80℃, for 30-120 min, preferably 60-100 min. Then the mixture is filtered, washed and dried.

[0057] (2) The soluble salt containing component L2 is mixed with the product of step (1) and deionized water at a mass ratio of 0.05-0.28:1:5-20, and the mixture is exchanged at a temperature of 50-90℃, preferably 60-80℃, for 30-120 min, preferably 60-100 min. Then the mixture is filtered, washed and dried.

[0058] Process Two:

[0059] (1) Mix the soluble salt containing component L2 with type A molecular sieve and deionized water at a mass ratio of 0.05-0.28:1:5-20, exchange at a temperature of 50-90℃, preferably 60-80℃ for 30-120 min, preferably 60-100 min, and then filter, wash and dry.

[0060] (2) The soluble salt containing component L1 is mixed with the product of step (1) and deionized water at a mass ratio of 0.4-2.5:1:5-20, and the mixture is exchanged at a temperature of 50-90℃, preferably 60-80℃, for 30-120 min, preferably 60-100 min. Then the mixture is filtered, washed and dried.

[0061] In step (1), the soluble salt containing component L2 is selected from Cr 3+ Cu 2+ Zn 2+ and Mn 2+ At least one of the nitrates or chlorides, wherein the soluble salt containing component L1 in step (2) is selected from Mg 2+ Ca 2+ and Sr 2+At least one of the following nitrates or chlorides. In some embodiments, the soluble salt containing component L2 is at least one of chromium nitrate, copper chloride, zinc nitrate, or manganese chloride, and the soluble salt containing component L1 is at least one of magnesium nitrate, calcium chloride, or strontium chloride.

[0062] Process 3:

[0063] Soluble salts containing component L1 and soluble salts containing component L2 are mixed with type A molecular sieves and deionized water at a mass ratio of 0.4-2.5:0.05-0.28:1:5-20. The mixed solution is exchanged at a temperature of 50-90℃, preferably 60-80℃, for 30-120 min, preferably 60-100 min, and then filtered, washed, and dried.

[0064] The soluble salt containing component L1 is selected from Mg 2+ Ca 2+ and Sr 2+ At least one of the nitrates or chlorides, wherein the soluble salt containing component L2 is selected from Cr 3+ Cu 2+ Zn 2+ and Mn 2+ At least one of the following nitrates or chlorides. In some embodiments, the soluble salt containing component L1 is at least one of magnesium nitrate, calcium chloride, or strontium chloride, and the soluble salt containing component L2 is at least one of chromium nitrate, copper chloride, zinc nitrate, or manganese chloride.

[0065] A second aspect of this application provides a method for concentrating ethylene, characterized by comprising the steps of selectively adsorbing a mixture of ethylene and ethane under adsorption conditions with a separation adsorbent; and desorbing ethylene from the adsorbent under desorption conditions; wherein the adsorbent is selected from the separation adsorbent of the first aspect of this application.

[0066] In this application, when a mixed gas of ethylene and ethane is contacted with a bed of ethylene-ethane separation adsorbent for selective adsorption, the ethylene content in the tail gas after passing through the ethylene-ethane separation adsorbent bed is determined using an Agilent 7890A gas chromatograph. When an ethylene signal can be detected in the tail gas, selective adsorption is stopped, i.e., step S2 is stopped.

[0067] In some embodiments, the adsorption conditions include an adsorption temperature of 10-40°C and an adsorption pressure of 0.5-1.0 MPa, preferably 0.6-0.8 MPa.

[0068] In some embodiments, the desorption conditions include a desorption temperature of 80-200°C and a desorption pressure of 0.001-0.1 MPa, preferably 0.005-0.08 MPa.

[0069] In some embodiments, the adsorbent is activated and then contacted with a mixture of ethylene and ethane. The activation is performed by treating the adsorbent in a nitrogen, argon, or helium atmosphere at a temperature of 150-450°C, preferably 200-400°C, for 30-180 minutes, preferably 60-150 minutes.

[0070] In some embodiments, the selective adsorption is carried out in a fixed bed or a moving bed. Preferably, the mass hourly space velocity (MSV) of the ethylene and ethane mixture is 0.3-3 h⁻¹. -1 .

[0071] The application allows for the use of Agilent's 7890A gas chromatograph to determine the volume ratio of ethylene and ethane after desorption from the ethylene-ethane separation adsorbent.

[0072] In this application, the definitions within the broadest scope and the preferred definitions can be combined to form new technical solutions, which are also considered to be disclosed in this specification.

[0073] The present application is illustrated by way of examples below, but should not be construed as limiting the scope of the present application.

[0074] Example

[0075] I. Instruments

[0076] Hydrothermal reaction equipment (KLJX-811 homogeneous reactor manufactured by Yantai Keli Chemical Equipment Co., Ltd.)

[0077] Magnetic stirring equipment (DF-101S heat-collecting magnetic heating stirrer manufactured by Jiangsu Jinyi Instrument Technology Co., Ltd.)

[0078] Vacuum filtration equipment with Buchner funnel and filtration flask (SHZ-D(III) type circulating water vacuum pump manufactured by Gongyi Yuhua Instrument Co., Ltd.).

[0079] Electric tableting equipment (DY-20 tabletop electric tableting machine manufactured by Tianjin Keqi High-Tech Co., Ltd.)

[0080] Gas quantitative detection equipment (Agilent Technologies 7890A gas chromatograph).

[0081] Adsorbent forming equipment (sugar coating machine manufactured by Guangzhou Xulang Machinery Equipment Co., Ltd.)

[0082] II. Raw Materials

[0083] All reagents used in the synthesis of type A molecular sieves were of analytical grade and purchased from Beijing Innocare Technology Co., Ltd.

[0084] All reagents used for ion exchange modification were chemically pure and purchased from Alfa Aesar, USA.

[0085] Ethylene (purity >99.99%), ethane (99.95%), and a mixture of ethylene and ethane were purchased from Beijing Helium North Branch Gas Industry Co., Ltd.

[0086] The carriers, such as kaolin, bentonite, montmorillonite, diatomite, attapulgite, and halloysite, used in the ethylene ethane separation adsorbent were purchased from Changling Branch of China Petroleum & Chemical Corporation.

[0087] III. Detection methods for modified type A molecular sieves

[0088] Chemical composition of modified type A molecular sieve: determined using a Rigaku ZSX100E X-ray fluorescence spectrometer (40kV, 250mA). Elemental analysis was performed based on the relationship that the intensity of fluorescence rays of each element is proportional to its concentration.

[0089] The average grain size of the modified type A molecular sieve was determined using a Hitachi S4800 scanning electron microscope (SEM) with an accelerating voltage of 5 kV, a working distance of 8 mm, and a magnification of 5 kV-50 kV. The size of each grain was measured according to the scale on the image, with at least 100 grains measured, and then statistically analyzed.

[0090] IV. Determination of products after ethylene concentration in a mixture of ethylene and ethane gases

[0091] The ratio of the peak areas of ethylene and ethane after desorption from the adsorbent is determined using an Agilent 7890A gas chromatograph, which is the volume ratio of ethylene to ethane.

[0092] Example 1

[0093] 1) Preparation of modified type A molecular sieves

[0094] Add 3.95g NaOH, 1.52g boehmite, and 7.54g tetraethyl orthosilicate to 38.5mL of deionized water, stir to obtain a mixed gel, transfer to an autoclave, age at 40℃ for 24h, after aging to 60℃ for 10h, filter the obtained hydrothermal reaction product, wash with deionized water until neutral, and dry at 100℃ to obtain 4A molecular sieve; weigh 4g of the obtained 4A molecular sieve, mix with 2.49g anhydrous CaCl2 and 40g deionized water, perform ion exchange at 70℃ for 95min, then filter, wash with deionized water until neutral, and dry at 100℃; weigh another 4g of the dried sample, and mix with 0.99g... Zn(NO3)2·6H2O and 60g of deionized water were mixed and subjected to ion exchange at 60℃ for 90min. The mixture was then filtered and washed with deionized water until neutral. Finally, it was dried at 100℃ to obtain the modified type A molecular sieve. The average grain size of the modified type A molecular sieve was 711nm. Its scanning electron microscope image is shown below. Figure 1 .

[0095] 2) Preparation of separation adsorbent

[0096] The modified type A molecular sieve and kaolin were mixed evenly at a mass ratio of 92:8 to form a mixed powder. The powder was placed in a sugar coating pan and 12wt% deionized water was sprayed in while rolling. Based on the weight of the mixed powder, it was then rolled into small balls with a particle size of 0.3-0.6mm.

[0097] 3) Concentrating ethylene from a mixture of ethylene and ethane gases

[0098] The above-mentioned ethylene-ethane separation adsorbent was activated at 450℃ under a nitrogen atmosphere for 30 min. Then, a mixture of ethylene and ethane at a volume ratio of 10:90 was introduced at 10℃ and 1.0 MPa for 3.0 h. -1 Selective adsorption was achieved by contacting the ethylene-ethane separation adsorbent bed with the adsorbent at a mass hourly space velocity (MHSV). The contact method was a moving bed. Selective adsorption was stopped when ethylene was detectable by gas chromatography in the tail gas after passing through the ethylene-ethane separation adsorbent bed. The temperature was then raised to 80°C and the pressure reduced to 0.001 MPa to desorb ethylene (and a small amount of ethane) from the adsorbent. The ethylene / ethane volume ratio of the desorbed ethylene and ethane was determined using a 7890A gas chromatograph. The results are shown in Table 1.

[0099] Example 2

[0100] Modified type A molecular sieves were prepared using the same conditions as in Example 1.

[0101] The separation adsorbent was prepared according to the method in Example 1, except that the carrier was montmorillonite and the mass ratio of modified type A molecular sieve to montmorillonite was 95:5.

[0102] The ethylene-ethane separation adsorbent was activated at 400℃ under an argon atmosphere for 60 min, and then a mixture of ethylene and ethane at a volume ratio of 25:75 was introduced at 20℃ and 0.6 MPa for 1.2 h. -1 Selective adsorption is achieved by contacting the ethylene-ethane separation adsorbent bed with the adsorbent at a mass hourly space velocity (MHSV). The contact method is a fixed bed. Selective adsorption is stopped when ethylene is detectable by gas chromatography in the tail gas after passing through the ethylene-ethane separation adsorbent bed. The temperature is then raised to 100°C and the pressure is reduced to 0.01 MPa to desorb ethylene (and a small amount of ethane) from the adsorbent. The volume ratio of ethylene to ethane after desorption from the ethylene-ethane separation adsorbent is determined using a 7890A gas chromatograph. The volume ratio of ethylene to ethane in the product is shown in Table 1.

[0103] Example 3

[0104] Modified type A molecular sieves were prepared using the same conditions as in Example 1.

[0105] The separation adsorbent was prepared according to the method in Example 1, except that the carrier was diatomaceous earth and the mass ratio of modified type A molecular sieve to diatomaceous earth was 92:8.

[0106] The ethylene-ethane separation adsorbent was activated at 150℃ under a nitrogen atmosphere for 180 min, and then a mixture of ethylene and ethane at a volume ratio of 1:99 was introduced at 30℃ and 0.5 MPa for 2.7 h. -1 Selective adsorption is achieved by contacting the ethylene-ethane separation adsorbent bed with the adsorbent at a mass hourly space velocity (MHSV). The contact method is a fixed bed. Selective adsorption is stopped when ethylene is detectable by gas chromatography in the tail gas after passing through the ethylene-ethane separation adsorbent bed. The temperature is then raised to 160°C and the pressure is reduced to 0.02 MPa to desorb ethylene (and a small amount of ethane) from the adsorbent. The volume ratio of ethylene to ethane after desorption from the ethylene-ethane separation adsorbent is determined using a 7890A gas chromatograph. The volume ratio of ethylene to ethane in the product is shown in Table 1.

[0107] Example 4

[0108] Modified type A molecular sieves were prepared using the same conditions as in Example 1.

[0109] The separation adsorbent was prepared according to the method in Example 1, except that the carrier was montmorillonite and the mass ratio of modified type A molecular sieve to montmorillonite was 94:6.

[0110] The ethylene-ethane separation adsorbent was activated at 250℃ under a helium atmosphere for 120 min, and then a mixture of ethylene and ethane at a volume ratio of 35:65 was introduced at 25℃ and 0.8 MPa for 0.6 h. -1Selective adsorption is achieved by contacting the ethylene-ethane separation adsorbent bed with the adsorbent at a mass hourly space velocity (MHSV). The contact method is a fixed bed. Selective adsorption is stopped when ethylene is detectable by gas chromatography in the tail gas after passing through the ethylene-ethane separation adsorbent bed. The temperature is then raised to 140°C and the pressure is reduced to 0.06 MPa to desorb ethylene (and a small amount of ethane) from the adsorbent. The volume ratio of ethylene to ethane after desorption from the ethylene-ethane separation adsorbent is determined using a 7890A gas chromatograph. The volume ratio of ethylene to ethane in the product is shown in Table 1.

[0111] Example 5

[0112] Modified type A molecular sieves were prepared using the same conditions as in Example 1.

[0113] The separation adsorbent was prepared according to the method in Example 1, except that the carrier was kaolin and the mass ratio of modified type A molecular sieve to kaolin was 96:4.

[0114] The ethylene-ethane separation adsorbent was activated at 200℃ under an argon atmosphere for 135 min, and then subjected to a 50:50 volume ratio of ethylene to ethane mixture at 20℃ and 0.6 MPa for 2.4 h. -1 Selective adsorption is achieved by contacting the ethylene-ethane separation adsorbent bed with the adsorbent at a mass hourly space velocity (MHSV). The contact method is a fixed bed. Selective adsorption is stopped when ethylene is detectable by gas chromatography in the tail gas after passing through the ethylene-ethane separation adsorbent bed. The temperature is then raised to 120°C and the pressure is reduced to 0.05 MPa to desorb ethylene (and a small amount of ethane) from the adsorbent. The volume ratio of ethylene to ethane after desorption from the ethylene-ethane separation adsorbent is determined using a 7890A gas chromatograph. The volume ratio of ethylene to ethane in the product is shown in Table 1.

[0115] Example 6

[0116] Modified type A molecular sieves were prepared using the same conditions as in Example 1.

[0117] The separation adsorbent was prepared according to the method in Example 1, except that the carrier was kaolin and the mass ratio of modified type A molecular sieve to kaolin was 91:9.

[0118] The ethylene-ethane separation adsorbent was activated at 350℃ under a nitrogen atmosphere for 90 min, and then a mixture of ethylene and ethane (volume ratio 30:70) was introduced at 40℃ and 0.6 MPa for 0.9 h. -1Selective adsorption is achieved by contacting the ethylene-ethane separation adsorbent bed with the adsorbent at a mass hourly space velocity (MHSV). The contact method is a fixed bed. Selective adsorption is stopped when ethylene is detectable by gas chromatography in the tail gas after passing through the ethylene-ethane separation adsorbent bed. The temperature is then raised to 200°C and the pressure is reduced to 0.005 MPa to desorb ethylene (and a small amount of ethane) from the adsorbent. The volume ratio of ethylene to ethane after desorption from the ethylene-ethane separation adsorbent is determined using a 7890A gas chromatograph. The volume ratio of ethylene to ethane in the product is shown in Table 1.

[0119] Example 7

[0120] Modified type A molecular sieves were prepared using the same conditions as in Example 1.

[0121] The separation adsorbent was prepared according to the method in Example 1, except that the carrier was kaolin and the mass ratio of modified type A molecular sieve to kaolin was 90:10.

[0122] The ethylene-ethane separation adsorbent was activated at 420℃ under a helium atmosphere for 45 min, and then a mixture of ethylene and ethane at a volume ratio of 15:85 was introduced at 15℃ and 0.9 MPa for 0.3 h. -1 Selective adsorption is achieved by contacting the ethylene-ethane separation adsorbent bed with the adsorbent at a mass hourly space velocity (MHSV). The contact method is a moving bed. Selective adsorption is stopped when ethylene is detectable by gas chromatography in the tail gas after passing through the ethylene-ethane separation adsorbent bed. The temperature is then raised to 100°C and the pressure is reduced to 0.1 MPa to desorb ethylene (and a small amount of ethane) from the adsorbent. The volume ratio of ethylene to ethane after desorption from the ethylene-ethane separation adsorbent is determined using a 7890A gas chromatograph. The volume ratio of ethylene to ethane in the product is shown in Table 1.

[0123] Example 8

[0124] Modified type A molecular sieves were prepared using the same conditions as in Example 1.

[0125] The separation adsorbent was prepared according to the method in Example 1, except that the carrier was bentonite and the mass ratio of modified type A molecular sieve to bentonite was 94:6.

[0126] The ethylene-ethane separation adsorbent was activated at 250℃ under a nitrogen atmosphere for 105 min, and then a mixture of ethylene and ethane at a volume ratio of 40:60 was introduced at 30℃ and 0.7 MPa for 1.8 h. -1Selective adsorption is achieved by contacting the ethylene-ethane separation adsorbent bed with the adsorbent at a mass hourly space velocity (MHSV). The contact method is a fixed bed. Selective adsorption is stopped when ethylene is detectable by gas chromatography in the tail gas after passing through the ethylene-ethane separation adsorbent bed. The temperature is then raised to 180°C and the pressure is reduced to 0.04 MPa to desorb ethylene (and a small amount of ethane) from the adsorbent. The volume ratio of ethylene to ethane after desorption from the ethylene-ethane separation adsorbent is determined using a 7890A gas chromatograph. The volume ratio of ethylene to ethane in the product is shown in Table 1.

[0127] Example 9

[0128] Modified type A molecular sieves were prepared using the same conditions as in Example 1.

[0129] The separation adsorbent was prepared according to the method in Example 1, except that the carrier was kaolin and the mass ratio of modified type A molecular sieve to kaolin was 97:3.

[0130] The ethylene-ethane separation adsorbent was activated at 200℃ under an argon atmosphere for 150 min, and then a mixture of ethylene and ethane at a volume ratio of 20:80 was introduced at 28℃ and 0.8 MPa for 1.5 h. -1 Selective adsorption is achieved by contacting the ethylene-ethane separation adsorbent bed with the adsorbent at a mass hourly space velocity (MHSV). The contact method is a fixed bed. Selective adsorption is stopped when ethylene is detectable by gas chromatography in the tail gas after passing through the ethylene-ethane separation adsorbent bed. The temperature is then raised to 160°C and the pressure is reduced to 0.08 MPa to desorb ethylene (and a small amount of ethane) from the adsorbent. The volume ratio of ethylene to ethane after desorption from the ethylene-ethane separation adsorbent is determined using a 7890A gas chromatograph. The volume ratio of ethylene to ethane in the product is shown in Table 1.

[0131] Example 10

[0132] Modified type A molecular sieves were prepared using the same conditions as in Example 1.

[0133] The separation adsorbent was prepared according to the method in Example 1, except that the carrier was diatomaceous earth and the mass ratio of modified type A molecular sieve to diatomaceous earth was 93:7.

[0134] The ethylene-ethane separation adsorbent was activated at 200℃ under an argon atmosphere for 150 min, and then subjected to a mixture of ethylene and ethane at a volume ratio of 45:55 at 35℃ and a pressure of 0.7 MPa for 2.1 h. -1Selective adsorption is achieved by contacting the ethylene-ethane separation adsorbent bed with the adsorbent at a mass hourly space velocity (MHSV). The contact method is a fixed bed. Selective adsorption is stopped when ethylene is detectable by gas chromatography in the tail gas after passing through the ethylene-ethane separation adsorbent bed. The temperature is then raised to 180°C and the pressure is reduced to 0.07 MPa to desorb ethylene (and a small amount of ethane) from the adsorbent. The volume ratio of ethylene to ethane after desorption from the ethylene-ethane separation adsorbent is determined using a 7890A gas chromatograph. The volume ratio of ethylene to ethane in the product is shown in Table 1.

[0135] Example 11

[0136] Add 2.47g NaOH, 1.68g boehmite, and 8g water glass (SiO2 251.5g / L, Na2O 176.65g / L) to 33.0mL deionized water, stir to obtain a mixed gel, transfer to a high-pressure hydrothermal reactor, age at 30℃ for 72h, after aging, raise the temperature to 90℃ and crystallize for 4h, filter the obtained hydrothermal reaction product, wash with deionized water until neutral, and dry at 100℃ to obtain 4A molecular sieve; weigh 4g of the obtained 4A molecular sieve, mix with 9.63g Mg(NO3)2·6H2O and 20g deionized water, perform ion exchange at 80℃ for 60min, then filter, wash with deionized water until neutral, and dry at 100℃; weigh 4g of the dried sample, and mix with 1.10g Cr(NO3)2·9H2O was mixed with 48g of deionized water and subjected to ion exchange at 50℃ for 120min. The mixture was then filtered and washed with deionized water until neutral. Finally, it was dried at 100℃ to obtain modified type A molecular sieve. The average grain size of the modified type A molecular sieve was 844nm.

[0137] The separation adsorbent was prepared according to the method in Example 6.

[0138] Ethylene was concentrated from a mixture of ethylene and ethane gas according to the method described in Example 6. The volume ratio of ethylene to ethane in the product is shown in Table 1.

[0139] Example 12

[0140] Add 3.5g NaOH, 1.35g sodium aluminate, and 1.88g solid silica gel to 38.5mL of deionized water, stir to obtain a mixed gel, transfer to a high-pressure hydrothermal reactor, age at 30℃ for 72h, after aging, raise the temperature to 80℃ and crystallize for 6h; filter the obtained hydrothermal reaction product, wash with deionized water until neutral, and dry at 100℃ to obtain 4A molecular sieve; weigh 4g of the obtained 4A molecular sieve, mix with 1.66g anhydrous CaCl2 and 44g deionized water, perform ion exchange at 90℃ for 40min, then filter and wash with deionized water until neutral, and dry at 100℃; weigh another 4g of the dried sample, mix with 0.74g Zn(NO3)2·6H2O and 32g deionized water, perform ion exchange at 90℃ for 30min, then filter and wash with deionized water until neutral, and dry at 100℃ to obtain modified type A molecular sieve. The average grain size of the modified type A molecular sieve is 872 nm.

[0141] The separation adsorbent was prepared according to the method in Example 6.

[0142] Ethylene was concentrated from a mixture of ethylene and ethane gas according to the method described in Example 6. The volume ratio of ethylene to ethane in the product is shown in Table 1.

[0143] Example 13

[0144] Add 2.47 g NaOH, 3.36 g aluminum isopropoxide, and 8 g water glass (SiO2 251.5 g / L, Na2O 176.65 g / L) to 33 mL of deionized water, stir to obtain a mixed gel, transfer to a high-pressure hydrothermal reactor, age at 25 °C for 4 h, after aging, raise the temperature to 80 °C and crystallize for 12 h; filter the obtained hydrothermal reaction product, wash with deionized water until neutral, and dry at 100 °C to obtain 4A molecular sieve; weigh 4 g of the obtained 4A molecular sieve, mix with 8.00 g SrCl2·6H2O and 60 g deionized water, perform ion exchange at 60 °C for 100 min, then filter, wash with deionized water until neutral, and dry at 100 °C; weigh another 4 g of the dried sample, and mix with 0.50 g Cr(NO3)2·9H2O and 20g of deionized water were mixed and subjected to ion exchange at 80℃ for 70min. The mixture was then filtered and washed with deionized water until neutral. The mixture was dried at 100℃ to obtain modified type A molecular sieve. The average grain size of the modified type A molecular sieve was 591nm.

[0145] The separation adsorbent was prepared according to the method in Example 6.

[0146] Ethylene was concentrated from a mixture of ethylene and ethane gas according to the method described in Example 6. The volume ratio of ethylene to ethane in the product is shown in Table 1.

[0147] Example 14

[0148] Add 5.27g NaOH, 3.36g aluminum isopropoxide, and 13.02g tetraethyl orthosilicate to 44.5mL of deionized water, stir to obtain a mixed gel, transfer to an autoclave, age at 40℃ for 24h, after aging, raise the temperature to 90℃ and crystallize for 12h; filter the obtained hydrothermal reaction product, wash with deionized water until neutral, and dry at 100℃ to obtain 4A molecular sieve; weigh 4g of the obtained 4A molecular sieve, mix with 0.99g MnCl2·4H2O and 72g deionized water, perform ion exchange at 60℃ for 110min, then filter, wash with deionized water until neutral, and dry at 100℃; weigh another 4g of the dried sample, and mix with 1.92g... Mg(NO3)2·6H2O and 32g of deionized water were mixed and subjected to ion exchange at 80℃ for 80min. The mixture was then filtered and washed with deionized water until neutral. Finally, it was dried at 100℃ to obtain modified type A molecular sieve. The average grain size of the modified type A molecular sieve was 759nm.

[0149] The separation adsorbent was prepared according to the method in Example 6.

[0150] Ethylene was concentrated from a mixture of ethylene and ethane gas according to the method described in Example 6. The volume ratio of ethylene to ethane in the product is shown in Table 1.

[0151] Example 15

[0152] Add 3.29 g NaOH, 1.34 g boehmite, and 1.88 g solid silica gel to 41.5 mL of deionized water, stir to obtain a mixed gel, transfer to a high-pressure hydrothermal reactor, age at 30 °C for 96 h, after aging, raise the temperature to 70 °C and crystallize for 2 h; filter the obtained hydrothermal reaction product, wash with deionized water until neutral, and dry at 100 °C to obtain 4A molecular sieve; weigh 4 g of the obtained 4A molecular sieve, mix with 3.33 g anhydrous CaCl2 and 64 g deionized water, perform ion exchange at 50 °C for 120 min, then filter and wash with deionized water until neutral, and dry at 100 °C; weigh another 4 g of the dried sample, mix with 0.58 g anhydrous CuCl2 and 44 g deionized water, perform ion exchange at 80 °C for 80 min, then filter and wash with deionized water until neutral, and dry at 100 °C to obtain modified type A molecular sieve. The average grain size of the modified type A molecular sieve is 460 nm.

[0153] The separation adsorbent was prepared according to the method in Example 6.

[0154] Ethylene was concentrated from a mixture of ethylene and ethane gas according to the method described in Example 6. The volume ratio of ethylene to ethane in the product is shown in Table 1.

[0155] Example 16

[0156] 1.07 g NaOH, 1.08 g sodium aluminate, and 8 g water glass (SiO2 251.5 g / L, Na2O 176.65 g / L) were added to 35.9 mL of deionized water and stirred to obtain a mixed gel. This gel was transferred to a high-pressure hydrothermal reactor and aged at 30 °C for 96 h. After aging, the temperature was raised to 70 °C and crystallized for 8 h. The resulting hydrothermal reaction product was filtered, washed with deionized water until neutral, and dried at 100 °C to obtain 4A molecular sieve. 4 g of the obtained 4A molecular sieve was weighed and mixed with 3.74 g anhydrous CaCl2, 0.25 g MnCl2·4H2O, and 52 g deionized water. Ion exchange was performed at 70 °C for 90 min, followed by filtration, washing with deionized water until neutral, and drying at 100 °C to obtain modified type A molecular sieve. The average grain size of the modified type A molecular sieve was 848 nm.

[0157] The separation adsorbent was prepared according to the method in Example 6.

[0158] Ethylene was concentrated from a mixture of ethylene and ethane gas according to the method described in Example 6. The volume ratio of ethylene to ethane in the product is shown in Table 1.

[0159] Example 17

[0160] Add 4.74 g NaOH, 1.08 g sodium aluminate, and 1.88 g solid silica gel to 44.5 mL of deionized water, stir to obtain a mixed gel, transfer to an autoclave, age at 30 °C for 120 h, after aging to 50 °C for 12 h; filter the obtained hydrothermal reaction product, wash with deionized water until neutral, and dry at 100 °C to obtain 4A molecular sieve; weigh 4 g of the obtained 4A molecular sieve, mix with 6 g SrCl2·6H2O and 48 g deionized water, perform ion exchange at 80 °C for 70 min, then filter, wash with deionized water until neutral, and dry at 100 °C; weigh another 4 g of the dried sample, and mix with 0.60 g... Zn(NO3)2·6H2O was mixed with 40g of deionized water and subjected to ion exchange at 70℃ for 60min. The mixture was then filtered and washed with deionized water until neutral. Finally, it was dried at 100℃ to obtain the modified type A molecular sieve. The average grain size of the modified type A molecular sieve was 745nm.

[0161] The separation adsorbent was prepared according to the method in Example 6.

[0162] Ethylene was concentrated from a mixture of ethylene and ethane gas according to the method described in Example 6. The volume ratio of ethylene to ethane in the product is shown in Table 1.

[0163] Example 18

[0164] Add 1.81 g NaOH, 1.35 g sodium aluminate, and 8 g water glass (SiO2 251.5 g / L, Na2O 176.65 g / L) to 33.0 mL of deionized water, stir to obtain a mixed gel, transfer to a high-pressure hydrothermal reactor, age at 30 °C for 36 h, after aging, raise the temperature to 70 °C and crystallize for 10 h; filter the obtained hydrothermal reaction product, wash with deionized water until neutral, and dry at 100 °C to obtain 4A molecular sieve; weigh 4 g of the obtained 4A molecular sieve and mix with 4 0.99 g of anhydrous CaCl2 and 80 g of deionized water were mixed and subjected to ion exchange at 80 °C for 60 min. The mixture was then filtered and washed with deionized water until neutral, and dried at 100 °C. 4 g of the dried sample was then weighed and mixed with 0.27 g of anhydrous CuCl2 and 32 g of deionized water, and subjected to ion exchange at 60 °C for 100 min. The mixture was then filtered and washed with deionized water until neutral, and dried at 100 °C to obtain the modified type A molecular sieve. The average grain size of the modified type A molecular sieve was 797 nm.

[0165] The separation adsorbent was prepared according to the method in Example 6.

[0166] Ethylene was concentrated from a mixture of ethylene and ethane gas according to the method described in Example 6. The volume ratio of ethylene to ethane in the product is shown in Table 1.

[0167] Example 19

[0168] Add 4.61g NaOH, 1.35g sodium aluminate, and 11.98g tetraethyl orthosilicate to 29.6mL of deionized water, stir to obtain a mixed gel, transfer to an autoclave, age at 40℃ for 12h, after aging, raise the temperature to 60℃ and crystallize for 12h; filter the obtained hydrothermal reaction product, wash with deionized water until neutral, and dry at 100℃ to obtain 4A molecular sieve; weigh 4g of the obtained 4A molecular sieve, mix with 0.33g MnCl2·4H2O and 80g deionized water, perform ion exchange at 70℃ for 90min, then filter, wash with deionized water until neutral, and dry at 100℃; weigh another 4g of the dried sample, and mix with 4g... SrCl2·6H2O was mixed with 72g of deionized water and subjected to ion exchange at 90℃ for 30min. The mixture was then filtered and washed with deionized water until neutral. Finally, it was dried at 100℃ to obtain the modified type A molecular sieve. The average grain size of the modified type A molecular sieve was 668nm.

[0169] The separation adsorbent was prepared according to the method in Example 6.

[0170] Ethylene was concentrated from a mixture of ethylene and ethane gas according to the method described in Example 6. The volume ratio of ethylene to ethane in the product is shown in Table 1.

[0171] Comparative Example 1

[0172] Add 3.95g NaOH, 1.52g boehmite and 7.54g tetraethyl orthosilicate to 38.5mL of deionized water, stir to obtain a mixed gel, transfer to a high-pressure hydrothermal reactor, age at 40℃ for 24h, after aging, raise the temperature to 60℃ and crystallize for 10h, filter the obtained hydrothermal reaction product, wash with deionized water until neutral, and dry at 100℃ to obtain 4A molecular sieve.

[0173] The separation adsorbent was prepared according to the method in Example 10.

[0174] Ethylene was concentrated from a mixture of ethylene and ethane gas according to the method in Example 10. The volume ratio of ethylene to ethane in the product is shown in Table 1.

[0175] Comparative Example 2

[0176] Add 3.95g NaOH, 1.52g boehmite, and 7.54g tetraethyl orthosilicate to 38.5mL of deionized water, stir to obtain a mixed gel, transfer to a high-pressure hydrothermal reactor, age at 40℃ for 24h, after aging, raise the temperature to 60℃ and crystallize for 10h, filter the obtained hydrothermal reaction product, wash with deionized water until neutral, and dry at 100℃ to obtain 4A molecular sieve; weigh 4g of the obtained 4A molecular sieve, mix with 2.49g anhydrous CaCl2 and 40g deionized water, perform ion exchange at 70℃ for 95min, then filter, wash with deionized water until neutral, and dry at 100℃ to obtain modified type A molecular sieve.

[0177] The separation adsorbent was prepared according to the method in Example 10.

[0178] Ethylene was concentrated from a mixture of ethylene and ethane gas according to the method in Example 10. The volume ratio of ethylene to ethane in the product is shown in Table 1.

[0179] Comparative Example 3

[0180] Add 3.95g NaOH, 1.52g boehmite, and 7.54g tetraethyl orthosilicate to 38.5mL of deionized water, stir to obtain a mixed gel, transfer to a high-pressure hydrothermal reactor, age at 40℃ for 24h, after aging, raise the temperature to 60℃ and crystallize for 10h, filter the obtained hydrothermal reaction product, wash with deionized water until neutral, and dry at 100℃ to obtain 4A molecular sieve; weigh 4g of the obtained 4A molecular sieve, mix with 0.99g Zn(NO3)2·6H2O and 60g deionized water, perform ion exchange at 60℃ for 90min, then filter and wash with deionized water until neutral, and dry at 100℃ to obtain modified type A molecular sieve.

[0181] The separation adsorbent was prepared according to the method in Example 10.

[0182] Ethylene was concentrated from a mixture of ethylene and ethane gas according to the method in Example 10. The volume ratio of ethylene to ethane in the product is shown in Table 1.

[0183] Comparative Example 4

[0184] Add 3.5g NaOH, 1.35g sodium aluminate and 1.88g solid silica gel to 38.5mL of deionized water, stir to obtain a mixed gel, transfer to a high-pressure hydrothermal reactor, age at 30℃ for 72h, after aging, raise the temperature to 80℃ and crystallize for 6h; filter the obtained hydrothermal reaction product, wash with deionized water until neutral, and dry at 100℃ to obtain 4A molecular sieve.

[0185] The separation adsorbent was prepared according to the method in Example 6.

[0186] Ethylene was concentrated from a mixture of ethylene and ethane gas according to the method described in Example 6. The volume ratio of ethylene to ethane in the product is shown in Table 1.

[0187] Comparative Example 5

[0188] Add 3.5g NaOH, 1.35g sodium aluminate, and 1.88g solid silica gel to 38.5mL of deionized water, stir to obtain a mixed gel, transfer to a high-pressure hydrothermal reactor, age at 30℃ for 72h, after aging, raise the temperature to 80℃ and crystallize for 6h; filter the obtained hydrothermal reaction product, wash with deionized water until neutral, and dry at 100℃ to obtain 4A molecular sieve; weigh 4g of the obtained 4A molecular sieve, mix with 1.66g anhydrous CaCl2 and 44g deionized water, perform ion exchange at 90℃ for 40min, then filter and wash with deionized water until neutral, and dry at 100℃ to obtain modified type A molecular sieve.

[0189] The separation adsorbent was prepared according to the method in Example 6.

[0190] Ethylene was concentrated from a mixture of ethylene and ethane gas according to the method described in Example 6. The volume ratio of ethylene to ethane in the product is shown in Table 1.

[0191] Comparative Example 6

[0192] Add 3.5g NaOH, 1.35g sodium aluminate, and 1.88g solid silica gel to 38.5mL of deionized water, stir to obtain a mixed gel, transfer to a high-pressure hydrothermal reactor, age at 30℃ for 72h, after aging, raise the temperature to 80℃ and crystallize for 6h; filter the obtained hydrothermal reaction product, wash with deionized water until neutral, and dry at 100℃ to obtain 4A molecular sieve; weigh 4g of the obtained 4A molecular sieve, mix with 0.74g Zn(NO3)2·6H2O and 32g deionized water, perform ion exchange at 90℃ for 30min, then filter and wash with deionized water until neutral, and dry at 100℃ to obtain modified type A molecular sieve.

[0193] The separation adsorbent was prepared according to the method in Example 6.

[0194] Ethylene was concentrated from a mixture of ethylene and ethane gas according to the method described in Example 6. The volume ratio of ethylene to ethane in the product is shown in Table 1.

[0195] Comparative Example 7

[0196] Add 4.61g NaOH, 1.35g sodium aluminate and 11.98g tetraethyl orthosilicate to 29.6mL of deionized water, stir to obtain a mixed gel, transfer to a high-pressure hydrothermal reactor, age at 40℃ for 12h, after aging, raise the temperature to 60℃ and crystallize for 12h; filter the obtained hydrothermal reaction product, wash with deionized water until neutral, and dry at 100℃ to obtain 4A molecular sieve.

[0197] The separation adsorbent was prepared according to the method in Example 6.

[0198] Ethylene was concentrated from a mixture of ethylene and ethane gas according to the method described in Example 6. The volume ratio of ethylene to ethane in the product is shown in Table 1.

[0199] Comparative Example 8

[0200] Add 4.61g NaOH, 1.35g sodium aluminate, and 11.98g tetraethyl orthosilicate to 29.6mL of deionized water, stir to obtain a mixed gel, transfer to a high-pressure hydrothermal reactor, age at 40℃ for 12h, after aging, raise the temperature to 60℃ and crystallize for 12h; filter the obtained hydrothermal reaction product, wash with deionized water until neutral, and dry at 100℃ to obtain 4A molecular sieve; weigh 4g of the obtained 4A molecular sieve, mix with 4g SrCl2·6H2O and 72g deionized water, perform ion exchange at 90℃ for 30min, then filter and wash with deionized water until neutral, and dry at 100℃ to obtain modified type A molecular sieve.

[0201] The separation adsorbent was prepared according to the method in Example 6.

[0202] Ethylene was concentrated from a mixture of ethylene and ethane gas according to the method described in Example 6. The volume ratio of ethylene to ethane in the product is shown in Table 1.

[0203] Comparative Example 9

[0204] Add 4.61g NaOH, 1.35g sodium aluminate, and 11.98g tetraethyl orthosilicate to 29.6mL of deionized water, stir to obtain a mixed gel, transfer to a high-pressure hydrothermal reactor, age at 40℃ for 12h, after aging, raise the temperature to 60℃ and crystallize for 12h; filter the obtained hydrothermal reaction product, wash with deionized water until neutral, and dry at 100℃ to obtain 4A molecular sieve; weigh 4g of the obtained 4A molecular sieve, mix with 0.33g MnCl2·4H2O and 80g deionized water, perform ion exchange at 70℃ for 90min, then filter, wash with deionized water until neutral, and dry at 100℃ to obtain modified type A molecular sieve.

[0205] The separation adsorbent was prepared according to the method in Example 6.

[0206] Ethylene was concentrated from a mixture of ethylene and ethane gas according to the method described in Example 6. The volume ratio of ethylene to ethane in the product is shown in Table 1.

[0207] Table 1

[0208]

[0209]

[0210] As shown in Table 1, compared with the ethylene / ethane volume ratio in the raw material, the ethylene concentration method of this application can increase the ethylene volume ratio in the product to over 75:25, resulting in an ethylene concentration increase of at least 66%. Compared with the separation adsorbents in the comparative examples that contain no active component, only active component L1, or only active component L2, the ethylene concentration in the product can be increased by at least 8 percentage points using the separation adsorbent of this application. Therefore, the ethylene concentration obtained by the ethylene concentration method of this application is high, the operation process is simple, energy consumption is low, and industrial operating costs are low, showing strong industrial application prospects.

Claims

1. An ethylene-ethane separation adsorbent, characterized in that, It comprises 90-97 wt% modified type A molecular sieve and 3-10 wt% support, wherein the modified type A molecular sieve includes type A molecular sieve and metal salt active component, wherein the metal salt active component includes component L1 and component L2, and component L1 is selected from Mg-containing... 2+ Ca 2+ and Sr 2+ At least one of the metal salts, wherein component L2 is a Zn-containing... 2+ The metal salt is based on a modified type A molecular sieve, wherein the type A molecular sieve comprises 75.0-95.0 wt%, the active metal salt component comprises 5.0-25.0 wt%, component L1 comprises 0.9-21.0 wt%, and component L2 comprises 1.5-7.0 wt%; the support is selected from at least one of kaolin, bentonite, montmorillonite, diatomite, palygorskite, and halloysite.

2. The ethylene-ethane separation adsorbent according to claim 1, characterized in that, Based on modified type A molecular sieve, component L1 is 4.5-16.0 wt%, and component L2 is 2.0-6.5 wt%.

3. The ethylene-ethane separation adsorbent according to claim 1, characterized in that, The modified type A molecular sieve has an average grain size of no more than 1 μm.

4. The ethylene-ethane separation adsorbent according to claim 3, characterized in that, The modified type A molecular sieve has an average grain size of no more than 0.9 μm.

5. The ethylene-ethane separation adsorbent according to claim 3, characterized in that, The modified type A molecular sieve has an average crystal size of 0.70-0.85 μm.

6. The ethylene-ethane separation adsorbent according to claim 1, characterized in that, The ethylene ethane separation adsorbent is a molded microsphere with a particle size of 0.3-0.6 mm.

7. A method for concentrating ethylene, characterized in that, The method includes the steps of selectively adsorbing a mixture of ethylene and ethane gases under adsorption conditions with a separation adsorbent; and desorbing ethylene from the adsorbent under desorption conditions; wherein the adsorbent is selected from the ethylene-ethane separation adsorbents of any one of claims 1-6.

8. The method according to claim 7, characterized in that, The adsorption conditions include an adsorption temperature of 10-40℃ and an adsorption pressure of 0.5-1.0MPa.

9. The method according to claim 8, characterized in that, The adsorption conditions include an adsorption pressure of 0.6-0.8 MPa.

10. The method according to claim 7, characterized in that, The desorption conditions include a desorption temperature of 80-200℃ and a desorption pressure of 0.001-0.1MPa.

11. The method according to claim 10, characterized in that, In the desorption conditions, the desorption pressure is 0.005-0.08 MPa.

12. The method according to claim 7, characterized in that, The adsorbent is activated and then contacted with a mixture of ethylene and ethane gas. The activation is performed by treating the adsorbent at a temperature of 150-450°C for 30-180 minutes in an atmosphere of nitrogen, argon, or helium.

13. The method according to claim 12, characterized in that, The activation is performed by treating the adsorbent at a temperature of 200-400℃ for 60-150 minutes under a nitrogen, argon, or helium atmosphere.

14. The method according to claim 7, characterized in that, The selective adsorption is carried out in a fixed bed or a moving bed.

15. The method according to claim 14, characterized in that, The mass hourly space velocity (MSV) of the ethylene and ethane mixture is 0.3–3 h⁻¹. -1 .

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