Composite adsorbents, methods of making and using the same, and methods of purifying oxygenates

Abstract

The present application relates to the field of oxygen-containing compound purification, and discloses a composite adsorbent, a preparation method and application thereof, and an oxygen-containing compound purification method.The composite adsorbent comprises modified molecular sieve and modified activated clay, the modified molecular sieve contains molecular sieve and a first modification component, the first modification component is magnesium and / or zinc; the modified activated clay contains activated clay and a second modification component, the second modification component is phosphorus, and sodium and / or zinc; wherein, the mass ratio of the modified molecular sieve to the modified activated clay is 1:0.3-1.5. The composite adsorbent provided by the present application can be applied to the field of oxygen-containing compound purification, and can efficiently and deeply remove aromatic hydrocarbons in an oxygen-containing compound solution.

Description

Technical Field

[0001] This invention relates to the field of oxygen-containing compound purification, specifically to a composite adsorbent, its preparation method and application, and a method for purifying oxygen-containing compounds. Background Technology

[0002] Ethylene and propylene are important basic organic chemical raw materials, the cornerstone of the chemical industry, closely related to people's lives, and occupy an important position in the national economy. In recent years, MTO technology using coal-based methanol as raw material has developed rapidly. MTO refers to the technology of producing ethylene, propylene, and other low-carbon olefins from methanol under the action of a catalyst. Inevitably, aldehyde, ketone, alcohol, and ether oxides are produced as byproducts in the MTO process, forming oxide wastewater that enters the water system. Directly returning some concentrated oxides to the MTO reactor for reprocessing results in low aldehyde and ketone conversion rates, and some remains as waste, leading to increasingly high treatment costs in recent years. How to effectively utilize these oxides and reduce the carbon-based loss of the raw material has gradually become a pressing problem to be solved in oxide conversion processes. To address the low conversion rate of MTO byproduct aldehyde, ketone, alcohol, and ether oxides in direct reprocessing, existing technologies employ catalysts to convert MTO byproduct oxides into alcohols before returning them to the MTO unit. However, some aromatic compounds in the MTO byproducts are prone to coking on the catalyst surface, reducing catalyst activity.

[0003] CN113477222A discloses a method for preparing an adsorbent for adsorbing aromatics using organosilicon-modified mesoporous molecular sieves, which is used for adsorbing polycyclic aromatic hydrocarbons in coking wastewater generated in the coking industry. However, this method uses organosilicon as a modifier, resulting in a complex process and high cost.

[0004] CN111996029A discloses a metal-modified mesoporous silica material for use in C6-C 10 Aromatic hydrocarbon adsorption is used for the purification of mixed aromatic hydrocarbons. However, this method does not take into account the influence of other components in organic wastewater on the adsorption process.

[0005] CN1098847705B describes the application of straw-modified biomass adsorbents as alternatives to activated carbon in the adsorption of chlorinated aromatic hydrocarbons. However, this method still uses carbon-based raw materials, making it difficult to solve the problems of secondary pollution and poor heat resistance during the adsorption process.

[0006] CN160111070A describes the preparation of a polycyclic aromatic hydrocarbon adsorbent using Fe3O4 magnetic microspheres coated with dopamine and modified with disulfide compounds. However, the material exhibits a low recovery rate for naphthalene.

[0007] CN106140078B describes a method for preparing a bimetallic aromatic hydrocarbon adsorbent, which modifies silicon dichloride with two metals to increase metal sites. However, this method results in unstable material structure, and the metal sites are easily lost, leading to adsorbent deactivation.

[0008] CN103483394B describes zinc-based metal-organic framework (MOF) materials for aromatic hydrocarbon adsorption, utilizing zinc as an active site for the selective adsorption of acenaphthene and anthracene in mixed polycyclic aromatic hydrocarbons. However, this method involves expensive materials, poor resistance to high temperatures, and easy structural damage, requiring a considerable amount of time to achieve practical wastewater treatment. Summary of the Invention

[0009] The purpose of this invention is to overcome the problems existing in the prior art and provide a composite adsorbent, its preparation method and application, and a method for purifying oxygen-containing compounds. Applying the composite adsorbent provided by this invention to the field of oxygen-containing compound purification can efficiently and deeply remove aromatic hydrocarbons from oxygen-containing compound solutions.

[0010] To achieve the above objectives, the first aspect of the present invention provides a composite adsorbent comprising a modified molecular sieve and modified activated clay, wherein the modified molecular sieve contains a molecular sieve and a first modifying component, the first modifying component being magnesium and / or zinc; and the modified activated clay contains activated clay and a second modifying component, the second modifying component being phosphorus, and sodium and / or zinc.

[0011] The mass ratio of modified molecular sieve to modified activated clay is 1:0.3-1.5.

[0012] A second aspect of this invention provides a method for preparing the composite adsorbent described in the first aspect, the method comprising the following steps:

[0013] (1) A first modifying component is introduced onto the molecular sieve by impregnation to obtain a modified molecular sieve;

[0014] (2) A second modifying component is introduced into the activated clay by impregnation to obtain modified activated clay;

[0015] (3) The modified molecular sieve, modified activated clay and optional adhesive are mixed and molded, and then dried and calcined.

[0016] The third aspect of this invention provides an application of the composite adsorbent described in the first aspect in the purification of oxygen-containing compounds.

[0017] A fourth aspect of the present invention provides a method for purifying oxygen-containing compounds, the method comprising contacting an oxygen-containing compound solution containing aromatic hydrocarbons with an adsorbent to remove aromatic hydrocarbons;

[0018] The adsorbent is the composite adsorbent described in the first aspect.

[0019] The beneficial effects of the present invention through the above technical solution include:

[0020] The composite adsorbent provided by this invention utilizes a specific ratio of modified molecular sieves and modified activated clay to synergistically enhance its adsorption performance. Applying this composite adsorbent to the purification of oxygen-containing compounds enables efficient and deep removal of aromatic hydrocarbons from solutions, facilitating the subsequent recovery and reuse of these compounds.

[0021] Moreover, the composite adsorbent described in this invention has a long service life; after 1000 hours of long-term operation, the aromatic hydrocarbon removal rate can still be maintained at over 99%. Detailed Implementation

[0022] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0023] In this invention, the terms "first," "second," and "third" do not limit the substances and operations, but are only used to distinguish the substances introduced in different steps and the operations performed in different stages.

[0024] The first aspect of the present invention provides a composite adsorbent comprising a modified molecular sieve and modified activated clay, wherein the modified molecular sieve contains a molecular sieve and a first modifying component, the first modifying component being magnesium and / or zinc; and the modified activated clay contains activated clay and a second modifying component, the second modifying component being phosphorus, and sodium and / or zinc.

[0025] The mass ratio of modified molecular sieve to modified activated clay is 1:0.3-1.5.

[0026] According to the present invention, preferably, the sum of the weak acid content and the medium-weak acid content of the composite adsorbent accounts for no more than 5% of the total acid content, specifically 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, and any two of these values ​​within a range, preferably 1-3%. This preferred embodiment is beneficial for improving the adsorption of aromatic compounds; however, excessively high levels of strong acid can lead to isomerization reactions, generating large molecular organic compounds, which is detrimental to the adsorption selectivity of aromatics.

[0027] The acid distribution of the composite adsorbent described in this invention was characterized using the NH3-TPD (NH3-temperature programmed desorption) method. The characterization method is as follows: 0.15 g (20-40 mesh) of the composite adsorbent sample was weighed, heated to 550°C for drying, and then cooled to 100°C to saturate the adsorbent with NH3. The temperature was then raised to 250°C, 350°C, 450°C, and 550°C to desorb NH3, and the NH3 concentration was detected using a TCD detector. The adsorption curves obtained at different temperature ranges were integrated, and the instrument automatically calculated the acid density distribution at different temperatures. Specifically, the acid content obtained at 250°C was identified as weak acid, 250-350°C as moderately weak acid, 350-450°C as moderately strong acid, and 450-550°C as strong acid.

[0028] According to the present invention, preferably, the specific surface area of ​​the composite adsorbent is 100-300 m². 2 / g, preferably 180-280m 2 / g.

[0029] According to the present invention, preferably, the pore volume of the composite adsorbent is 0.4-1 cm³. 3 / g, preferably 0.4-0.8cm 3 / g.

[0030] According to the present invention, preferably, the pore size of the composite adsorbent is in the range of 2-10 nm.

[0031] The specific surface area, pore volume, and pore size of the composite adsorbent described in this invention were measured by BET.

[0032] According to the present invention, the mass ratio of modified molecular sieve to modified activated clay is 1:0.3-1.5, specifically 1:0.3, 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, and the range of any two of these values, preferably 1:0.3-1.

[0033] In this invention, the content of each component in the composite adsorbent is obtained by calculation based on the amount of feed.

[0034] According to the present invention, preferably, in the modified molecular sieve, the mass content of the first modifying component, calculated by element, is 0.2-25%, specifically 0.2%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, and the range of any two of these values, preferably 0.5-15%.

[0035] According to the present invention, preferably, in the modified activated clay, the mass content of the second modifying component, calculated by element, is 0.3-25%, specifically 0.3%, 0.6%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, and the range of any two of these values, preferably 0.6-15%.

[0036] According to the present invention, preferably, in the second modified component, the mass ratio of phosphorus to sodium is 1:5-30, more preferably 1:10-20, based on elemental composition.

[0037] According to the present invention, preferably, in the second modified component, the mass ratio of phosphorus to zinc, by element, is 1:20-50, more preferably 1:25-40.

[0038] According to the present invention, preferably, the second modifying component is phosphorus, sodium, and zinc. The inventors of the present invention have discovered that using the above-mentioned preferred second modifying component is more conducive to the selective adsorption of aromatic compounds, while simultaneously extending the lifespan of the composite adsorbent.

[0039] According to the present invention, preferably, the silicon-aluminum molar ratio of the molecular sieve is 5-50, more preferably 10-35.

[0040] According to the present invention, preferably, the molecular sieve has a D 90 Not greater than 10μm, preferably 1-5μm.

[0041] Using molecular sieves with the above characteristics is beneficial to improving the adsorption activity of adsorbents and extending the lifespan of composite adsorbents.

[0042] According to the present invention, preferably, the molecular sieve is selected from at least one of ZSM-5 molecular sieve, Y molecular sieve and MCM-41 molecular sieve.

[0043] The present invention does not particularly limit the source of the molecular sieve. As long as a molecular sieve with the above characteristics can be obtained, it can be obtained by commercial purchase or by self-production using conventional methods in the art.

[0044] According to the present invention, preferably, the activated clay has a D 90 No larger than 50 μm, preferably 10-20 μm.

[0045] According to the present invention, preferably, the specific surface area of ​​the activated clay is 100-300 m². 2 / g, preferably 200-300m 2 / g.

[0046] According to the present invention, preferably, the pore size of the activated clay is in the range of 5-50 nm, and more preferably in the range of 10-30 nm.

[0047] Using activated clay with the above characteristics is beneficial to improving the surface area and pore structure of the composite adsorbent, and is more conducive to improving the adsorption activity of the adsorbent.

[0048] The present invention does not particularly limit the source of the activated clay, as long as the activated clay with the above characteristics can be obtained, it can be obtained by commercial purchase or by self-production using conventional methods in the art.

[0049] A second aspect of this invention provides a method for preparing the composite adsorbent described in the first aspect, the method comprising the following steps:

[0050] (1) A first modifying component is introduced onto the molecular sieve by impregnation to obtain a modified molecular sieve;

[0051] (2) A second modifying component is introduced into the activated clay by impregnation to obtain modified activated clay;

[0052] (3) The modified molecular sieve, modified activated clay and optional adhesive are mixed and molded, and then dried and calcined.

[0053] In this invention, the introduction of the first modified component onto the molecular sieve can be carried out by conventional methods in the art. Preferably, the first modified component is introduced onto the molecular sieve by impregnation.

[0054] Preferably, the impregnation method in step (1) includes: impregnating the molecular sieve in a solution containing the first modified component compound, and then performing a first drying and a first calcination.

[0055] In the preparation method provided by this invention, the impregnation method in step (1) can be either a saturated impregnation method or a supersaturated impregnation method. There are no particular limitations on the environment for the impregnation method; it can be carried out under sealed conditions or in an open environment according to conventional methods in the art. This invention does not particularly limit the conditions for impregnation in step (1), and the specific impregnation method is a conventional choice in the art.

[0056] The present invention does not particularly limit the first modifying component compound, as long as it contains the first modifying component. Preferably, the first modifying component compound is selected from at least one of the chloride, nitrate and sulfate of the first modifying component.

[0057] The present invention allows for a wide range of solvent choices in the solution containing the first modified component compound, and can be a conventional choice in the art. In an exemplary embodiment of the present invention, water is used as the solvent.

[0058] The present invention does not impose any particular limitations on the first drying and the first calcination, and can be carried out with reference to conventional methods in the art. Preferably, the conditions for the first calcination include: a temperature of 300-650°C and a time of 2-6 hours.

[0059] Preferably, the impregnation method in step (2) includes: impregnating activated clay in a solution containing a second modified component compound, followed by a second drying and a second calcination.

[0060] In the preparation method provided by this invention, the impregnation method in step (2) can be either a saturated impregnation method or a supersaturated impregnation method. There are no particular limitations on the environment for the impregnation method; it can be carried out under sealed conditions or in an open environment according to conventional methods in the art. This invention does not particularly limit the conditions for impregnation in step (2), and the specific impregnation method is a conventional choice in the art.

[0061] This invention does not particularly limit the second modifying compound, as long as it contains a second modifying component. For example, the phosphorus-containing compound is preferably selected from at least one of phosphoric acid, sodium dihydrogen phosphate, and sodium phosphate. The zinc-containing compound is preferably selected from at least one of zinc nitrate, zinc sulfate, and zinc chloride. The sodium-containing compound is preferably selected from at least one of sodium chloride, sodium nitrate, and sodium sulfate.

[0062] The present invention allows for a wide range of solvent choices in the solution containing the second modified component compound, which can be conventional choices in the art. In an exemplary embodiment of the present invention, water is used as the solvent.

[0063] The present invention does not have any particular limitation on the second drying process, which can be carried out with reference to conventional methods in the art.

[0064] Preferably, the conditions for the second calcination include: a temperature of 200-400℃ and a time of 2-8h.

[0065] Step (3) of the present invention, mixing and molding, can be carried out with reference to conventional methods in the art.

[0066] The adhesive solvent described in this invention can be any conventional choice in the art. Preferably, the adhesive solvent is selected from at least one of nitric acid, hydrochloric acid, sulfuric acid, phosphoric acid, formic acid, and acetic acid.

[0067] In this invention, there is no particular limitation on the amount of adhesive solvent used, as long as it can meet the adhesive requirements. Those skilled in the art can select according to actual needs.

[0068] In the mixing process described in step (3) of this invention, an extrusion aid may also be added. The extrusion aid may be a conventional choice in the art, such as guar gum powder, methylcellulose, water-soluble starch, etc.

[0069] In this invention, there is no particular limitation on the amount of extrusion aid, as long as it can ensure the smooth progress of subsequent molding. Those skilled in the art can select according to actual needs.

[0070] Water may also be added during the mixing process described in step (3) of this invention.

[0071] In this invention, there is no particular limitation on the amount of water used, as long as it can ensure the smooth progress of subsequent molding. Those skilled in the art can choose according to actual needs.

[0072] The present invention does not impose any particular limitation on the molding method in step (3), and those skilled in the art can choose according to actual needs. An exemplary embodiment of the present invention uses extrusion molding.

[0073] According to the present invention, preferably, the conditions for the third drying in step (3) include: a temperature of 50-80°C and a time of 6-24 hours.

[0074] According to the present invention, preferably, the conditions for the third calcination in step (3) include: a temperature of 200-500°C and a time of 5-12 hours.

[0075] The third aspect of this invention provides an application of the composite adsorbent described in the first aspect in the purification of oxygen-containing compounds.

[0076] A fourth aspect of the present invention provides a method for purifying oxygen-containing compounds, the method comprising contacting an oxygen-containing compound solution containing aromatic hydrocarbons with an adsorbent to remove aromatic hydrocarbons;

[0077] The adsorbent is the composite adsorbent described in the first aspect.

[0078] The composite adsorbent provided by this invention, when applied to the purification of oxygen-containing compounds, can efficiently and deeply remove aromatics from oxygen-containing compound solutions, achieving a high aromatic removal rate. Preferably, the aromatic removal process results in an aromatic removal rate of not less than 99% in the oxygen-containing compound solution.

[0079] This invention offers a wide range of operating conditions for the aromatic removal process, which can be appropriately selected based on specific circumstances, ensuring that the aromatic removal rate in the oxygen-containing compound solution is not less than 99%. Preferably, the aromatic removal operating conditions include: a temperature of 80-120℃, a pressure of 0.1-0.6 MPa, and a mass hourly space velocity (HHSV) of 0.5-5 h⁻¹. -1 .

[0080] According to the present invention, preferably, in the oxygen-containing compound solution, the water content is 20-75% by mass, more preferably 50-70%; the aromatic hydrocarbon content is 0.1-5% by mass, more preferably 1-3%; and the oxygen-containing compound content is 20-75% by mass, more preferably 25-45%.

[0081] According to the present invention, preferably, the aromatic hydrocarbon includes at least one selected from toluene, ethylbenzene, trimethylbenzene, tetramethylbenzene, pentamethylbenzene, hexamethylbenzene and methylnaphthalene.

[0082] According to the present invention, preferably, the oxygen-containing compound includes at least one of ketones, aldehydes, ethers and alcohols, more preferably at least one of acetone, butanone, pentanone, hexanone, methanol, ethanol, propanol, isopropanol, acetaldehyde, propionaldehyde, butanone and pentanone.

[0083] The present invention will be described in detail below through embodiments.

[0084] The contents of the first modified component in the modified molecular sieve and the contents of the second modified component in the modified activated clay were determined by ICP method.

[0085] The silicon-to-aluminum molar ratio of the molecular sieve described in this invention was determined by ICP method;

[0086] The particle size distribution of the molecular sieve and activated clay described in this invention was measured using a laser particle size analyzer.

[0087] The specific surface area and pore size of the activated clay described in this invention were measured by the BET method.

[0088] Example 1

[0089] Weigh out silicon and aluminum in a molar ratio of 25, D 90 A 2.5 μm ZSM-5 molecular sieve was added to a magnesium nitrate aqueous solution with a concentration of 61.7 w / w% (the percentage of nitrate / water, the same below), stirred and mixed for 1 h, allowed to stand and soak for 16 h, filtered, dried overnight at 80 °C, and calcined at 500 °C for 5 h to obtain a modified ZSM-5 molecular sieve, wherein the mass content of magnesium element is 9.09%.

[0090] Weigh out an average pore size of 20 nm and a specific surface area of ​​250 m². 2 / g,D 90 Modified activated clay (15 μm) was added to a mixed aqueous solution of 2 w / w phosphoric acid and 34.6 w / w sodium nitrate. The mixture was stirred for 1 hour, allowed to stand for 20 hours, filtered, dried at 80°C, and calcined at 250°C for 5 hours. The sodium content was 8.5% and the phosphorus content was 0.57%.

[0091] 100g of modified ZSM-5 molecular sieve and 50g of modified activated clay were added to 5g of guar gum powder, 0.8g of nitric acid and 40g of water and mixed. The mixture was then kneaded in a kneader until it agglomerated and extruded into strips. The strips were dried at 80℃ for 24h and calcined at 300℃ for 6h to obtain composite adsorbent A1. Its composition and characteristic parameters are shown in Table 1.

[0092] Example 2

[0093] Weigh out a silicon-aluminum molar ratio of 20, D 90 A 1 μm MCM-41 molecular sieve was added to a 30.8 w / w% magnesium nitrate aqueous solution, stirred and mixed for 1 h, allowed to stand and soak for 24 h, filtered, dried overnight at 80 °C, and calcined at 500 °C for 4 h to obtain a modified MCM-41 molecular sieve with a magnesium content of 4.75%.

[0094] Weigh out an average pore size of 30 nm and a specific surface area of ​​250 m². 2 / g,D 90 10 μm activated clay was added to a mixed aqueous solution of 3 w / w phosphoric acid and 52 w / w sodium nitrate, stirred for 1 h, allowed to stand for 24 h, filtered, dried at 80 °C, and calcined at 300 °C for 5 h to obtain modified activated clay. The sodium content was 12.2% and the phosphorus content was 0.82% by mass.

[0095] 100g of modified MCM-41 molecular sieve and 50g of modified activated clay were added to 10g of guar gum powder, 1g of nitric acid and 40g of water and mixed. The mixture was then kneaded in a kneader until it agglomerated and extruded into strips. The strips were dried at 80℃ for 24h and calcined at 350℃ for 5h to obtain composite adsorbent A2. Its composition and characteristic parameters are shown in Table 1.

[0096] Example 3

[0097] Weigh out silicon and aluminum in a molar ratio of 25, D 90 A 2.5 μm Y-type molecular sieve was added to a 61.6 w / w% zinc nitrate aqueous solution, stirred and mixed for 1 h, allowed to stand and soak for 24 h, filtered, dried overnight at 80 °C, and calcined at 500 °C for 5 h to obtain a modified Y-type molecular sieve with a zinc content of 9.08%.

[0098] Weigh out an average pore size of 20 nm and a specific surface area of ​​290 m². 2 / g,D 9015 μm activated clay was added to a mixed aqueous solution of 1 w / w phosphoric acid, 31 w / w zinc nitrate, and 14.6 w / w sodium nitrate. The mixture was stirred for 1 h, allowed to stand and soak for 20 h, filtered, dried at 80 °C, and calcined at 200 °C for 5 h to obtain modified activated clay, wherein the mass content of sodium was 3.43%, the mass content of phosphorus was 0.27%, and the mass content of zinc was 9.27%.

[0099] 100g of modified Y-type molecular sieve and 100g of modified activated clay were added to 2.5g of guar gum powder, 0.5g of nitric acid and 20g of water and mixed. The mixture was then kneaded in a kneader until it agglomerated and extruded into strips. The strips were dried at 80℃ for 24h and calcined at 350℃ for 5h to obtain composite adsorbent A3. Its composition and characteristic parameters are shown in Table 1.

[0100] Example 4

[0101] Weigh out silicon and aluminum in a molar ratio of 25, D 90 A 2.5 μm ZSM-5 molecular sieve was added to a 61.7 w / w% magnesium nitrate aqueous solution, stirred and mixed for 1 h, allowed to stand and soak for 16 h, filtered, dried overnight at 80 °C, and calcined at 500 °C for 5 h to obtain a modified ZSM-5 molecular sieve with a magnesium content of 9.09%.

[0102] Weigh out an average pore size of 20 nm and a specific surface area of ​​250 m². 2 / g,D 90 Modified activated clay (15 μm) was added to a mixed aqueous solution of 2 w / w phosphoric acid and 34.6 w / w sodium nitrate. The mixture was stirred for 1 hour, allowed to stand for 20 hours, filtered, dried at 80°C, and calcined at 250°C for 5 hours. The sodium content was 8.51% and the phosphorus content was 0.58% by mass.

[0103] Weigh 30g of modified ZSM-5 molecular sieve and 45g of modified activated clay, add 1.67g of guar gum powder, 0.4g of nitric acid and 20g of water, mix them and put them into a kneader for kneading. After the mixture clumps together, extrude it into strips, dry it at 80℃ for 24h, and calcine it at 300℃ for 6h to obtain composite adsorbent A4. Its composition and characteristic parameters are shown in Table 1.

[0104] Comparative Example 1

[0105] The procedure was carried out according to Example 3, except that the first modified component in the molecular sieve was copper. Specifically, this included weighing out a silicon-to-aluminum molar ratio of 25, D... 90A 2.5 μm Y-type molecular sieve was added to a 29.3 w / w% copper nitrate aqueous solution, stirred for 1 h, allowed to stand for 24 h, filtered, dried overnight at 80 °C, and calcined at 250 °C for 5 h to obtain a modified Y-type molecular sieve. The mass content of copper was 9.07%.

[0106] The composite adsorbent D1 was obtained, and its composition and characteristic parameters are shown in Table 1.

[0107] Comparative Example 2

[0108] The method of Example 3 was followed, except that the second modified component in the activated clay was calcium, specifically comprising: weighing out an average pore size of 20 nm and a specific surface area of ​​290 m². 2 / g,D 90 15μm activated clay was added to an aqueous solution of calcium nitrate with a concentration of 59.4 w / w%, stirred and mixed for 1 h, allowed to stand and soak for 20 h, filtered, dried at 80℃, and calcined at 200℃ for 5 h to obtain modified activated clay, wherein the mass content of calcium element was 12.65%.

[0109] The composite adsorbent D2 was obtained, and its composition and characteristic parameters are shown in Table 1.

[0110] Table 1

[0111]

[0112] Test Example 1

[0113] The adsorbent from Example 3 was used in a fixed-bed reactor to adsorb aromatic hydrocarbons from an oxygen-containing compound solution. The composition of the oxygen-containing compound solution was: water 60 wt%, aromatic hydrocarbons (toluene, ethylbenzene, xylene, trimethylbenzene) 1.5 wt%, acetone 20 wt%, butanone 10 wt%, and acetaldehyde 8.5 wt%. The reactor was operated at 100°C, 0.4 MPa, and a mass hourly space velocity (HHSV) of 1 h⁻¹. -1 Adsorption was carried out under the specified conditions, and the adsorption results are shown in Table 2.

[0114] Test Example 2

[0115] The adsorbent from Example 3 was used in a fixed-bed reactor to adsorb aromatic hydrocarbons from an oxygen-containing compound solution. The composition of the oxygen-containing compound solution was: water 62 wt%, aromatic hydrocarbons (toluene, ethylbenzene, xylene, trimethylbenzene) 2.5 wt%, acetone 17 wt%, methyl ethyl ketone 12 wt%, and acetaldehyde 6.5 wt%. The reactor was operated at 100°C, 0.4 MPa, and a mass hourly space velocity (HHSV) of 1 h⁻¹. -1 Adsorption was carried out under the specified conditions, and the adsorption results are shown in Table 2.

[0116] Test Example 3

[0117] The adsorbent from Example 1 was used in a fixed-bed reactor to adsorb aromatics from an oxygen-containing compound solution. The composition of the oxygen-containing compound solution was: water 60 wt%, aromatics (toluene, ethylbenzene, xylene, trimethylbenzene) 1.5 wt%, acetone 20 wt%, butanone 10 wt%, and acetaldehyde 8.5 wt%. The reactor was operated at 100°C, 0.4 MPa, and a mass hourly space velocity (HHSV) of 1 h⁻¹. -1 Adsorption was carried out under the specified conditions, and the adsorption results are shown in Table 2.

[0118] Test Example 4

[0119] The adsorbent from Example 2 was used in a fixed-bed reactor to adsorb aromatics from an oxygen-containing compound solution. The composition of the oxygen-containing compound solution was: water 60 wt%, aromatics (toluene, ethylbenzene, xylene, trimethylbenzene) 1.5 wt%, acetone 20 wt%, butanone 10 wt%, and acetaldehyde 8.5 wt%. The reactor was operated at 100°C, 0.4 MPa, and a mass hourly space velocity (HHSV) of 1 h⁻¹. -1 Adsorption was carried out under the specified conditions, and the adsorption results are shown in Table 2.

[0120] Test Example 5

[0121] The adsorbent from Example 4 was used in a fixed-bed reactor to adsorb aromatics from an oxygen-containing compound solution. The composition of the oxygen-containing compound solution was: water 60 wt%, aromatics (toluene, ethylbenzene, xylene, trimethylbenzene) 1.5 wt%, acetone 20 wt%, butanone 10 wt%, and acetaldehyde 8.5 wt%. The reactor was operated at 100°C, 0.4 MPa, and a mass hourly space velocity (HHSV) of 1 h⁻¹. -1 Adsorption was carried out under the specified conditions, and the adsorption results are shown in Table 2.

[0122] Test Example 6

[0123] The adsorbent of Comparative Example 1 was loaded into a fixed-bed reactor to conduct adsorption experiments on aromatic hydrocarbons in an oxygen-containing compound solution. The composition of the oxygen-containing compound solution was: water 60 wt%, aromatic hydrocarbons (toluene, ethylbenzene, xylene, trimethylbenzene) 1.5 wt%, acetone 20 wt%, methyl ethyl ketone 10 wt%, and acetaldehyde 8.5 wt%. The reactor was operated at a temperature of 100 °C, a pressure of 0.4 MPa, and a mass hourly space velocity (HHSV) of 1 h⁻¹. -1 Adsorption was carried out under the specified conditions, and the adsorption results are shown in Table 2.

[0124] Test Example 7

[0125] The adsorbent of Comparative Example 2 was loaded into a fixed-bed reactor to conduct adsorption experiments on aromatic hydrocarbons in an oxygen-containing compound solution. The composition of the oxygen-containing compound solution was: water 60 wt%, aromatic hydrocarbons (toluene, ethylbenzene, xylene, trimethylbenzene) 1.5 wt%, acetone 20 wt%, methyl ethyl ketone 10 wt%, and acetaldehyde 8.5 wt%. The reactor was operated at a temperature of 100 °C, a pressure of 0.4 MPa, and a mass hourly space velocity (HHSV) of 1 h⁻¹. -1Adsorption was carried out under the specified conditions, and the adsorption results are shown in Table 2.

[0126] Table 2

[0127] Test Case Number Composite Adsorbent Number Running time h Aromatic hydrocarbon removal rate % Test Example 1 A3 1000 99.8 Test Example 2 A3 1000 99.8 Test Example 3 A1 1000 99.3 Test Example 4 A2 1000 99.2 Test Example 5 A4 1000 98.5 Test Example 6 D1 1000 85.2 Test Example 7 D2 1000 78.2

[0128] As can be seen from the results in Table 2, the composite adsorbent of this invention exhibits a higher aromatic hydrocarbon removal rate when applied to the purification of oxygen-containing compounds. This demonstrates that the composite adsorbent described in this invention possesses superior adsorption activity.

[0129] Furthermore, after 1000 hours of continuous operation, the aromatic hydrocarbon removal rate of the composite adsorbent in this embodiment of the invention remains above 95.2%. This demonstrates that the composite adsorbent described in this invention possesses high stability.

[0130] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A composite adsorbent, characterized in that, The composite adsorbent comprises a modified molecular sieve and modified activated clay. The modified molecular sieve contains a molecular sieve and a first modifying component, wherein the first modifying component is magnesium and / or zinc. The modified activated clay contains activated clay and a second modifying component, wherein the second modifying component is phosphorus, and sodium and / or zinc. The mass ratio of modified molecular sieve to modified activated clay is 1:0.3-1.

5.

2. The composite adsorbent according to claim 1, wherein, The sum of the weak acid and the medium-weak acid in the composite adsorbent accounts for no more than 5% of the total acid content, preferably 1-3%. Preferably, the specific surface area of ​​the composite adsorbent is 100-300 m². 2 / g, preferably 180-280m 2 / g; Preferably, the composite adsorbent has a pore volume of 0.4-1 cm³. 3 / g, preferably 0.45-0.8cm 3 / g; Preferably, the pore size of the composite adsorbent is in the range of 2-10 nm.

3. The composite adsorbent according to claim 1 or 2, wherein, The mass ratio of modified molecular sieve to modified activated clay is 1:0.3-1; Preferably, in the modified molecular sieve, the mass content of the first modifying component, calculated by element, is 0.2-25%, more preferably 0.5-15%; Preferably, in the modified activated clay, the mass content of the second modifying component, calculated by element, is 0.3-25%, more preferably 0.6-15%.

4. The composite adsorbent according to any one of claims 1-3, wherein, In the second modified component, the mass ratio of phosphorus to sodium, by elemental basis, is 1:5-30, preferably 1:10-20; and / or, In the second modified component, the mass ratio of phosphorus to zinc is 1:20-50, preferably 1:25-40, based on elemental composition. Preferably, the second modified component is phosphorus, sodium, and zinc.

5. The composite adsorbent according to any one of claims 1-4, wherein, The Si / Al molar ratio of the molecular sieve is 5-50, preferably 10-35; Preferably, the molecular sieve has a D 90 Not larger than 10 μm, preferably 1-5 μm; Preferably, the molecular sieve is selected from at least one of ZSM-5 molecular sieve, Y molecular sieve and MCM-41 molecular sieve.

6. The composite adsorbent according to any one of claims 1-5, wherein, The activated clay of D 90 No larger than 50 μm, preferably 10-20 μm; Preferably, the specific surface area of ​​the activated clay is 100-300 m². 2 / g, preferably 200-300m 2 / g; Preferably, the average pore size of the activated clay is 5-50 nm, and more preferably 10-30 nm.

7. A method for preparing the composite adsorbent according to any one of claims 1-6, the method comprising the following steps: (1) A first modifying component is introduced onto the molecular sieve by impregnation to obtain a modified molecular sieve; (2) A second modifying component is introduced into the activated clay by impregnation to obtain modified activated clay; (3) The modified molecular sieve, modified activated clay and optional adhesive solvent are mixed and molded, and then subjected to a third drying and a third calcination. Preferably, the conditions for the third drying in step (3) include: a temperature of 50-80°C and a time of 6-24 hours; Preferably, the conditions for the third roasting in step (3) include: a temperature of 200-500℃ and a time of 5-12h.

8. The application of the composite adsorbent according to any one of claims 1-6 in the purification of oxygen-containing compounds.

9. A method for purifying oxygen-containing compounds, characterized in that, The purification method includes contacting an oxygen-containing compound solution containing aromatics with an adsorbent to remove aromatics; Wherein, the adsorbent is the composite adsorbent according to any one of claims 1-6.

10. The purification method according to claim 9, wherein, The aromatic removal process ensures that the aromatic removal rate in the oxygen-containing compound solution is not less than 99%. Preferably, the dearomatics removal operating conditions include: a temperature of 80-120°C, a pressure of 0.1-0.6 MPa, and a mass hourly space velocity of 0.5-5 h⁻¹. -1 .

11. The purification method according to claim 9, wherein, In the oxygen-containing compound solution, the water content is 20-75% by mass, preferably 50-70%; the aromatic hydrocarbon content is 0.1-5% by mass, preferably 1-3%; and the oxygen-containing compound content is 20-75% by mass, preferably 25-45%. Preferably, the aromatic hydrocarbon includes at least one selected from toluene, ethylbenzene, trimethylbenzene, tetramethylbenzene, pentamethylbenzene, hexamethylbenzene, and methylnaphthalene; Preferably, the oxygen-containing compound includes at least one of ketones, aldehydes, ethers, and alcohols, and more preferably includes at least one of acetone, butanone, pentanone, hexanone, methanol, ethanol, propanol, isopropanol, acetaldehyde, propionaldehyde, butanone, and pentanone.

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