Adsorbent grading method for purification of hydrocarbon feedstocks and purification method of hydrocarbon feedstocks

Abstract

The present application relates to the field of purification, disclose a kind of adsorbent gradation method and purification method of hydrocarbon raw material for hydrocarbon raw material purification.The method includes renewable adsorbent and non-renewable adsorbent arranged in turn along the direction of flow, non-renewable adsorbent includes molecular sieve, binder, Salen ligand and transition metal element, based on the total amount of non-renewable adsorbent, the content of molecular sieve is 30-80wt%, the content of binder is 5-60wt%, the content of Salen ligand is 1-8wt%, the content of transition metal element is 1-8wt%, wherein, the Salen ligand has the structure as described in the following formula (1);R1 And R2 Each is independently selected from H, halogen, amino or C1-C5 Alkyl.The gradation method provided by the application can remove mercaptan and sulfide impurities in raw material simultaneously by using two kinds of adsorbents in combination,

Description

Technical Field

[0001] This invention relates to the field of purification, specifically to an adsorbent gradation method and a purification method for hydrocarbon raw materials. Background Technology

[0002] C4 feedstocks are abundant, typically consisting of butane, 1-butene, 2-butene, isobutene, butadiene, and other products or mixtures. Separation yields various C4 feedstocks with wide-ranging downstream applications, including MTBE, methyl ethyl ketone, maleic anhydride, and synthetic rubber. However, C4 feedstocks often contain sulfur impurities. The presence of these impurities negatively impacts polymerization and hydrogenation catalysts, affecting their efficiency. Therefore, efficient removal of sulfur compounds is crucial for protecting the main catalyst in downstream units and maintaining long-term stable operation.

[0003] The sulfur impurities in C4 feedstock mainly consist of thiols and thioethers. Currently, widely used industrial removal technologies include Merox extraction-oxidation and fiber membrane desulfurization. However, both of these technologies generate waste alkaline solutions and lack sufficient desulfurization precision. Adsorption desulfurization technology, on the other hand, offers advantages such as high removal precision, recyclable adsorbents, no waste alkaline solutions, and low investment costs, making it a green and environmentally friendly technology.

[0004] CN115537244A discloses a method for adsorption desulfurization of liquefied petroleum gas (LPG). The method includes: S1, mixing LPG feedstock with hydrogen and feeding the mixture into the lower part of a moving bed reactor, where it is cross-flow contacted with an adsorption desulfurization catalyst fed from the top or upper part of the moving bed reactor to undergo an adsorption desulfurization reaction, obtaining reaction products and a spent catalyst; S2, sending the spent catalyst to a regenerator for regeneration to obtain a regenerated catalyst, and then sending the regenerated catalyst to the top or upper part of the moving bed reactor for reduction; wherein the conditions for the adsorption desulfurization reaction include: a reaction temperature of 120-400℃, a reaction pressure of 0.5-5 MPa, and a weight hourly space velocity of 0.1-100 h⁻¹. -1 This method is complex to operate, requires high temperatures, and consumes a lot of energy.

[0005] CN111748374A discloses a method and system for the hydrogenation refining of mixed C4 feedstocks. The method involves reacting a mixed C4 feedstock and an inert gas with a thiol etherification catalyst in a first reactor. After separation of the reaction effluent, the resulting low-sulfur mixed C4 material is reacted with a selective hydrogenation dediene catalyst in a second reactor to undergo a dediene reaction, yielding a low-sulfur, low-dien mixed C4 product. This method significantly reduces the risk of sulfur poisoning in the selective hydrogenation dediene catalyst, substantially extends the catalyst's service life, and achieves a high single-ene yield. However, this method requires hydrogen access and has high energy consumption.

[0006] CN1048543A discloses a caustic alkali-free desulfurization method for sulfur-containing hydrocarbon streams. This method involves contacting the hydrocarbon fraction with a catalytic complex in the presence of an oxidant, ammonium hydroxide, and a quaternary ammonium salt. However, this method, which uses alkali treatment, presents a problem related to the regeneration of waste liquid. Summary of the Invention

[0007] The purpose of this invention is to overcome the problems existing in the prior art and provide an adsorbent gradation method and a method for purifying hydrocarbon raw materials. The method provided by this invention employs two adsorbent materials, which are used in combination to achieve the purification of hydrocarbon raw materials.

[0008] To achieve the above objectives, the first aspect of the present invention provides an adsorbent gradation method for purifying hydrocarbon feedstocks. The gradation method includes a regenerable adsorbent and a non-regenerable adsorbent arranged sequentially along the flow direction. The non-regenerable adsorbent includes a molecular sieve, a binder, a Salen ligand, and a transition metal element. Based on the total amount of the non-regenerable adsorbent, the molecular sieve content is 30-80% by weight, the binder content is 5-60% by weight, the Salen ligand content is 1-8% by weight, and the transition metal element content is 1-8% by weight. The Salen ligand has the structure described in formula (1).

[0009]

[0010] R1 and R2 are each independently selected from H, halogen, amino, or C1-C5 alkyl groups.

[0011] Preferably, based on the total amount of non-renewable adsorbent, the molecular sieve content is 45-70% by weight, the binder content is 25-45% by weight, the Salen ligand content is 1.5-6% by weight, and the transition metal element content is 1.5-6% by weight.

[0012] Preferably, the molecular sieve is selected from at least one of FAU type molecular sieve, UFI type molecular sieve and MWW type molecular sieve, and is preferably FAU type molecular sieve.

[0013] A second aspect of the present invention provides a method for purifying hydrocarbon raw materials. The method includes injecting the hydrocarbon raw material to be purified into a purification system for adsorption under adsorption conditions, wherein the adsorbent in the purification system is filled according to the adsorbent gradation method described in the first aspect of the present invention.

[0014] This invention employs two types of adsorbent materials: a regenerable adsorbent primarily used to remove sulfide impurities from the raw materials, and a non-regenerable adsorbent primarily used to remove mercaptan impurities. Both adsorbents exhibit strong selective adsorption capabilities for sulfide and mercaptan impurities, respectively. By using these two adsorbents in combination, the purification of hydrocarbon raw materials, particularly C4 raw materials, can be achieved. Attached Figure Description

[0015] Figure 1 This is a schematic flowchart of a method for purifying hydrocarbon raw materials according to one embodiment of the present invention. Detailed Implementation

[0016] 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.

[0017] The first aspect of the present invention provides an adsorbent gradation method for purifying hydrocarbon feedstocks. The gradation method includes a regenerable adsorbent and a non-regenerable adsorbent arranged sequentially along the flow direction. The non-regenerable adsorbent includes a molecular sieve, a binder, a Salen ligand, and a transition metal element. Based on the total amount of the non-regenerable adsorbent, the content of the molecular sieve is 30-80% by weight, the content of the binder is 5-60% by weight, the content of the Salen ligand is 1-8% by weight, and the content of the transition metal element is 1-8% by weight. The Salen ligand has the structure described in formula (1).

[0018]

[0019] R1 and R2 are each independently selected from H, halogen, amino, or C1-C5 alkyl groups.

[0020] In this invention, the non-renewable adsorbent enhances the binding force between thiol impurities and the adsorbent through a rational combination of molecular sieves, binders, Salen ligands, and transition metal elements, thereby achieving selective adsorption performance. When used in conjunction with a renewable adsorbent, it can improve the purification precision of raw materials.

[0021] In this invention, Salen ligands have the conventional meaning in the art, and their benzene rings may or may not be substituted. This invention offers a wide range of choices for R1 and R2, each independently selected from H, halogens, amino groups, or C1-C5 alkyl groups. Preferably, the halogen is any one of Cl, Br, and I; the C1-C5 alkyl group is preferably any one of methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, tert-pentyl, and neopentyl.

[0022] According to the present invention, preferably, based on the total amount of the non-renewable adsorbent, the molecular sieve content is 45-70% by weight, for example, 45%, 50%, 55%, 60%, 65%, 70% by weight, or any range thereof; the binder content is 25-45% by weight, for example, 25%, 30%, 35%, 40%, 45% by weight, or any range thereof; and the Salen ligand content is 1.5- The concentration of the adsorbent is 6% by weight, for example, 1.5% by weight, 2% by weight, 2.5% by weight, 3% by weight, 3.5% by weight, 4% by weight, 4.5% by weight, 5% by weight, 5.5% by weight, 6% by weight, or any range thereof; the concentration of the transition metal element is 1.5-6% by weight, for example, 1.5% by weight, 2% by weight, 2.5% by weight, 3% by weight, 3.5% by weight, 4% by weight, 4.5% by weight, 5% by weight, 5.5% by weight, 6% by weight, or any range thereof. This preferred embodiment can further enhance the adsorption capacity of thiol impurities and the adsorbent, improve the selective adsorption performance of the adsorbent, and thereby remove thiol impurities.

[0023] According to the present invention, the range of molecular sieve types is relatively wide. Preferably, the molecular sieve is selected from at least one of FAU-type molecular sieves, UFI-type molecular sieves, and MWW-type molecular sieves, with FAU-type molecular sieves being the most preferred. In this preferred embodiment, the FAU-type molecular sieve has a special pore structure, which, in combination with binders, Salen ligands, and transition metal elements, gives the non-renewable adsorbent higher adsorption performance.

[0024] In this invention, the type of FAU molecular sieve is not particularly limited and can be any type commonly used in the art, preferably X-type molecular sieve and / or Y-type molecular sieve. The UFI type molecular sieve can be, for example, UZM-5 molecular sieve, and the MWW type molecular sieve can be, for example, UZM-8 molecular sieve.

[0025] According to the present invention, preferably, the silicon-to-aluminum ratio of the FAU-type molecular sieve is 1-3:1. This preferred embodiment allows for a lower silicon-to-aluminum ratio to provide more active sites, which is more beneficial for improving the adsorption performance of the adsorbent. In this invention, the silicon-to-aluminum ratio refers to the atomic ratio of silicon to aluminum.

[0026] According to the present invention, preferably, the transition metal element is selected from at least one of Group VIII, Group IB and Group IIB metal elements.

[0027] In this invention, the Group VIII metal elements include, but are not limited to, Fe, Co, Ni, Pd, Pt and Ru, with Fe, Co and Ni being preferred.

[0028] In this invention, the Group IB metal elements include, but are not limited to, Cu, Ag and Au, with Cu being preferred.

[0029] In this invention, the group IIB metal elements include, but are not limited to, Zn and Cd, with Zn being preferred.

[0030] Furthermore, the transition metal element is preferably at least one selected from Cu, Zn, Fe, Ni, and Co, with Cu being the most preferred. This preferred embodiment is more conducive to the adsorption of sulfur impurities.

[0031] This invention does not impose any particular limitation on the existence form of molecular sieves, binders, Salen ligands, and transition metal elements in non-renewable adsorbents. As long as the above-mentioned components are used in accordance with the above-mentioned proportions, the purpose of this invention can be achieved. Specifically, the Salen ligands and the transition metal elements can exist independently, or in the form of a complex, or they can exist partially independently and partially in the form of a complex.

[0032] According to the present invention, preferably, at least a portion of the transition metal and at least a portion of the Salen ligand are present in the form of a transition metal complex. This preferred embodiment is more conducive to the adsorption of sulfur impurities.

[0033] In this invention, the presence of transition metal complexes can be determined by FTIR characterization.

[0034] In this invention, there is no particular limitation on the type of binder in the non-renewable adsorbent, and it can be any binder commonly used in the art, preferably alumina.

[0035] The present invention does not particularly limit the preparation method of the non-renewable adsorbent. Preferably, the preparation method of the non-renewable adsorbent includes:

[0036] (1) Mix the molecular sieve with a binder and / or a binder precursor, then dry and calcine to obtain solid product A;

[0037] (2) Introducing a transition metal element into the solid product A to obtain solid product B;

[0038] (3) Mix solid product B and Salen ligand under the following conditions: temperature 150-200℃ and time 1-10 hours.

[0039] Step (1) of the present invention can use an adhesive, an adhesive precursor, or a mixture of the two. The present invention does not have any particular limitation on this, but an adhesive is preferred.

[0040] The present invention does not particularly limit the type of the binder precursor, and it can be any substance that is converted into a binder through subsequent steps. For example, when the binder is alumina, the binder precursor can be boehmite and / or aluminate.

[0041] According to the present invention, there are no particular limitations on the morphology of the non-renewable adsorbent, and those skilled in the art can make an adaptive selection according to the application scenario. The non-renewable adsorbent can be a molded body or a powder. When the non-renewable adsorbent is a molded body, the preparation method of the non-renewable adsorbent further includes a step of molding the non-renewable adsorbent. Preferably, in step (1), the molecular sieve is mixed with a binder and / or a binder precursor, and then molded. There are no particular limitations on the specific method of molding, and it can be any method conventionally used in the art, including but not limited to tableting, extrusion, and ball rolling. Specifically, it can be a mixture of molecular sieve, binder and / or binder precursor, followed by the addition of acid for kneading, and then molding. Preferably, the acid is nitric acid and / or hydrochloric acid. The present invention does not particularly limit the amount and concentration of acid added, and it can be carried out according to conventional methods in the art, which will not be elaborated here.

[0042] According to the present invention, preferably, the drying conditions in step (1) include: a temperature of 50-150°C and a time of 8-16h; more preferably, the temperature is 100-130°C and the time is 10-14h.

[0043] According to the present invention, preferably, the calcination conditions in step (1) include: a temperature of 200-500℃ and a time of 2-10h; more preferably, the temperature is 300-450℃ and the time is 3-8h.

[0044] In this invention, there are no particular limitations on the method of introducing transition metal elements into the solid product A, the standard being that the transition metal elements can be introduced into the solid product A.

[0045] According to the present invention, preferably, step (2) involves introducing a transition metal element onto the solid product A by impregnation.

[0046] In this invention, the impregnation method is not particularly limited and can be any conventional impregnation method in the art, preferably equal-volume impregnation. This preferred embodiment has a high utilization rate of the transition metal used, which is beneficial to improving the adsorption performance of the adsorbent.

[0047] The specific procedures for impregnation are well known to those skilled in the art, and will not be described in detail here.

[0048] According to the present invention, the transition metal is provided in the form of a metal salt, preferably selected from at least one of acetate, nitrate and sulfate.

[0049] In this invention, the metal salt is provided in the form of a metal salt solution, which is prepared by adding a solvent to the metal salt. The amount of solvent used is sufficient to completely dissolve the soluble salt corresponding to the active component. There are no specific requirements for the type of solvent, but water and / or ethanol are preferred.

[0050] In this invention, after introducing a transition metal element onto the solid product A in step (2), the process also includes drying and calcination steps.

[0051] According to the present invention, preferably, the drying conditions in step (2) include: a temperature of 50-150°C and a time of 6-14h; more preferably, the temperature is 100-130°C and the time is 6-10h.

[0052] According to the present invention, preferably, the calcination conditions in step (2) include: a temperature of 200-500℃ and a time of 2-10h; more preferably, the temperature is 300-450℃ and the time is 3-8h.

[0053] The present invention does not particularly limit the source of the Salen ligand; it can be commercially available or a product prepared by any existing method.

[0054] According to the present invention, preferably, the Salen ligand in step (3) is prepared by means of: reflux reaction of salicylaldehyde and ethylenediamine in the presence of an organic solvent, followed by solid-liquid separation to obtain the Salen ligand.

[0055] In this invention, the preparation method of the Salen ligand does not particularly limit the type of organic solvent; it can be any organic solvent commonly used in the art, preferably ethanol. The amount of organic solvent used is also not particularly limited, as long as it is sufficient to mix evenly with the reactants.

[0056] According to the present invention, there are no particular limitations on the amount of salicylaldehyde and ethylenediamine used, as well as the specific conditions and methods of the reflux reaction. They can be carried out by conventional means in the art, and the present invention will not elaborate further here.

[0057] In this invention, there are no particular limitations on the method of solid-liquid separation, as long as it can achieve solid-liquid separation, such as filtration. In this invention, Salen ligands are separated from the reaction products through solid-liquid separation.

[0058] According to the present invention, preferably, the mixing conditions in step (3) include: a temperature of 160-190°C and a time of 2-6 hours.

[0059] According to the present invention, preferably, the mixing of solid product B and Salen ligand in step (3) is carried out under vacuum conditions. Using this preferred embodiment, Salen ligand can enter solid product B at a lower temperature without decomposition, thereby improving the adsorption performance of the adsorbent.

[0060] In this invention, after the solid product B and Salen ligand are mixed in step (3), a cooling step under a protective gas can be included to obtain the non-renewable adsorbent.

[0061] In this invention, there is no particular limitation on the type of protective gas, which can be any inert gas commonly used in the art, preferably at least one of nitrogen, argon and helium.

[0062] This invention allows for a wide selection of the type of regenerable adsorbent, which can be any adsorbent conventionally used in the art, as long as it meets the regeneration requirement. Preferably, the regenerable adsorbent includes a second molecular sieve and a binder. This invention also allows for a wide selection of the binder in the regenerable adsorbent, which can be the same as or different from the binder in the non-regenerable adsorbent, but preferably the same. Preferably, the binder is alumina.

[0063] According to the present invention, preferably, based on the total amount of regenerable adsorbent, the content of the second molecular sieve is 50-80% by weight and the content of the binder is 20-50% by weight; more preferably, based on the total amount of regenerable adsorbent, the content of the second molecular sieve is 55-75% by weight and the content of the binder is 25-45% by weight.

[0064] The present invention allows for a wide range of choices for the type of second molecular sieve, with the requirement that it can selectively adsorb sulfide impurities. Preferably, the second molecular sieve is selected from at least one of 3A, 4A, 5A, 13X and NaY.

[0065] The present invention does not have any particular limitation on the source of the renewable adsorbent. It can be commercially available or prepared by any existing method, which will not be described in detail here.

[0066] According to a preferred embodiment of the present invention, the weight ratio of the regenerable adsorbent to the non-regenerable adsorbent is 1:(1-3), preferably 1:(1-2). This preferred embodiment is more advantageous in further improving the purification accuracy of the two adsorbents for hydrocarbon feedstocks.

[0067] A second aspect of the present invention provides a method for purifying hydrocarbon raw materials. The method includes injecting the hydrocarbon raw material to be purified into a purification system for adsorption under adsorption conditions, wherein the adsorbent in the purification system is filled according to the adsorbent gradation method described in the first aspect of the present invention.

[0068] The present invention does not impose any particular limitation on the purification system, and can be any reactor capable of allowing the hydrocarbon feedstock to be purified to be adsorbed by the adsorbent under adsorption conditions, such as a fixed-bed reactor.

[0069] In this invention, there are no particular limitations on the filling method of the renewable adsorbent and the non-renewable adsorbent. They can be filled in one or more reactors connected in series, as long as the renewable adsorbent and the non-renewable adsorbent are filled sequentially along the flow direction.

[0070] According to the present invention, preferably, the hydrocarbon raw material to be purified undergoes primary adsorption using a renewable adsorbent and secondary adsorption using a non-renewable adsorbent.

[0071] In this invention, the conditions for primary and secondary adsorption can be the same or different, with a wide range of choices. Preferably, the conditions for primary and secondary adsorption each independently include a weight hourly space velocity (WHSV) of 0.1-8 h⁻¹. -1 The pressure is 1-3 MPa, and the temperature is 0-40℃; more preferably, the weight hourly space velocity is 0.5-6 h⁻¹. -1 The pressure is 1.2-2.5 MPa and the temperature is 5-35℃.

[0072] According to the present invention, preferably, the regenerable adsorbent is regenerated after it has become saturated with adsorption.

[0073] The present invention allows for a wide range of selection of regeneration conditions. Preferably, the regeneration conditions include: a nitrogen atmosphere and a space velocity of 500-2000 h⁻¹. -1 The temperature is 200-350℃, and the time is 2-10 hours.

[0074] In order for the purification method to operate continuously, preferably under the following conditions, such as Figure 1As shown, the reactors filled with regenerable adsorbent are operated in pairs, with one reactor in use and the other in standby mode. When one reactor is in use, the other reactor is regenerated and ready for use. When the adsorbent in one reactor is saturated, it is removed from the system and the standby reactor is put in, and the cycle repeats.

[0075] The present invention has a wide range of applicable types of hydrocarbon raw materials to be purified; any raw material that requires selective adsorption and separation by an adsorbent is suitable for the method of the present invention. Preferably, the hydrocarbon raw material to be purified is a low-carbon hydrocarbon raw material, more preferably including C4 hydrocarbons.

[0076] The C4 hydrocarbons have the conventional meaning in the art, including butane, 1-butene, 2-butene, isobutene, and butadiene.

[0077] According to the present invention, preferably, the hydrocarbon raw material to be purified also includes sulfur-containing impurities. The sulfur-containing impurities include, but are not limited to, thiols and thioethers.

[0078] According to the present invention, preferably, the content of sulfur impurities in the hydrocarbon raw material to be purified is not higher than 1000 ppm, and more preferably not higher than 500 ppm.

[0079] According to the present invention, preferably, the content of mercaptan impurities in the hydrocarbon raw material to be purified is not higher than 200 ppm, and the content of thioether impurities is not higher than 200 ppm.

[0080] The present invention will be described in detail below through embodiments.

[0081] All raw materials used in the preparation examples, comparative examples, and comparative examples are commercially available.

[0082] The renewable adsorbent used in the following examples consists of 60 wt% 13X molecular sieve (silicon-to-aluminum ratio of 1.3) and 40 wt% alumina.

[0083] The following preparation examples illustrate the preparation of non-renewable adsorbents.

[0084] Preparation Example 1

[0085] (1) Mix 600g of Y-type molecular sieve (silicon-to-aluminum ratio of 2.5) and 400g of alumina evenly, then add 300g of HNO3 (3%) and knead. After kneading, extrude the mixture into strips, dry it at 120℃ for 12h, and then calcine it at 400℃ for 5h to obtain solid product A.

[0086] (2) Impregnate 500g of solid product A with copper acetate, then dry at 120°C for 8h, and calcine at 400°C for 5h to obtain solid product B, so that the loading of Cu is 4% of solid product B.

[0087] (3) Dissolve 1 mol of salicylaldehyde in ethanol, add 0.5 mol of ethylenediamine ethanol solution dropwise, reflux for 1 h, cool and filter to obtain Salen ligand. Then mix 500 g of solid product B with 20 g of Salen ligand, heat at 180 °C under vacuum for 2 h, cool under nitrogen atmosphere to obtain non-renewable adsorbent N1, in which the content of Y-type molecular sieve is 55.6 wt%, the content of alumina is 37%, the content of Salen ligand is 3.7 wt%, and the content of Cu is 3.7%.

[0088] Preparation Example 2

[0089] (1) Mix 600g of Y-type molecular sieve (silicon-to-aluminum ratio of 2.5) and 400g of alumina evenly, then add 300g of HNO3 (3%) and knead. After kneading, extrude the mixture into strips, dry it at 120℃ for 12h, and then calcine it at 400℃ for 5h to obtain solid product A.

[0090] (2) Impregnate 500g of solid product A with copper acetate, then dry at 120°C for 8h, and calcine at 400°C for 5h to obtain solid product B, so that the loading of Cu is 6% of solid product B.

[0091] (3) Dissolve 1 mol of salicylaldehyde in ethanol, add 0.5 mol of ethylenediamine ethanol solution dropwise, reflux for 1 h, cool and filter to obtain Salen ligand. Then mix 500 g of solid product B with 30 g of Salen ligand, heat at 180 °C under vacuum for 2 h, cool under nitrogen atmosphere to obtain adsorbent N2, in which the content of Y-type molecular sieve is 53.2 wt%, the content of alumina is 35.4 wt%, the content of Salen ligand is 5.7 wt%, and the content of Cu is 5.7 wt%.

[0092] Preparation Example 3

[0093] (1) Mix 600g of X-type molecular sieve (silicon-to-aluminum ratio of 1.3) and 400g of alumina evenly, then add 300g of HNO3 (3%) and knead. After kneading, extrude the mixture into strips, dry it at 120℃ for 12h, and then calcine it at 400℃ for 5h to obtain solid product A.

[0094] (2) Impregnate 500 g of solid product A with copper acetate, then dry at 120°C for 8 h, and calcine at 400°C for 5 h to obtain solid product B, such that the loading of Cu is 2% of solid product B.

[0095] (3) Dissolve 1 mol of salicylaldehyde in ethanol, add 0.5 mol of ethylenediamine ethanol solution dropwise, reflux for 1 h, cool and filter to obtain Salen ligand. Then mix 500 g of solid product B with 10 g of Salen ligand, heat at 180 °C under vacuum for 2 h, cool under nitrogen atmosphere to obtain adsorbent N3, in which the content of Y-type molecular sieve is 57.7 wt%, the content of alumina is 38.5 wt%, the content of Salen ligand is 1.9 wt%, and the content of Cu is 1.9 wt%.

[0096] Preparation Example 4

[0097] (1) Mix 600g of Y-type molecular sieve (silicon-to-aluminum ratio of 2.5) and 400g of alumina evenly, then add 300g of HNO3 (3%) and knead. After kneading, extrude the mixture into strips, dry it at 120℃ for 12h, and then calcine it at 400℃ for 5h to obtain solid product A.

[0098] (2) Impregnate 500g of solid product A with copper acetate, then dry at 120°C for 8h, and calcine at 400°C for 5h to obtain solid product B, such that the loading of Cu is 1% of solid product B.

[0099] (3) Dissolve 1 mol of salicylaldehyde in ethanol, add 0.5 mol of ethylenediamine ethanol solution dropwise, reflux for 1 h, cool and filter to obtain Salen ligand. Then mix 500 g of solid product B with 5 g of Salen ligand, heat at 180 °C under vacuum for 2 h, cool under nitrogen atmosphere to obtain adsorbent N4, wherein the content of Y-type molecular sieve is 58.8 wt%, the content of alumina is 39.2 wt%, the content of Salen ligand is 1 wt%, and the content of Cu is 1 wt%.

[0100] Preparation Example 5

[0101] (1) Mix 600g of UZM-5 molecular sieve (silicon-aluminum ratio of 8) and 400g of alumina evenly, then add 300g of HNO3 (3%) and knead. After kneading, extrude the mixture into strips, dry it at 120℃ for 12h, and then calcine it at 400℃ for 5h to obtain solid product A.

[0102] (2) Impregnate 500g of solid product A with copper acetate, then dry at 120°C for 8h, and calcine at 400°C for 5h to obtain solid product B, so that the loading of Cu is 4% of solid product B.

[0103] (3) Dissolve 1 mol of salicylaldehyde in ethanol, add 0.5 mol of ethylenediamine ethanol solution dropwise, reflux for 1 h, cool and filter to obtain Salen ligand. Then mix 500 g of solid product B with 20 g of Salen ligand, heat at 180 °C under vacuum for 2 h, cool under nitrogen atmosphere to obtain adsorbent N5, wherein the content of Y-type molecular sieve is 55.6 wt%, the content of alumina is 37 wt%, the content of Salen ligand is 3.7 wt%, and the content of Cu is 3.7 wt%.

[0104] Preparation Example 6

[0105] (1) Mix 600g of UZM-8 molecular sieve (silicon-aluminum ratio of 20) and 400g of alumina evenly, then add 300g of HNO3 (3%) and knead. After kneading, extrude the mixture into strips, dry it at 120℃ for 12h, and then calcine it at 400℃ for 5h to obtain solid product A.

[0106] (2) Impregnate 500g of solid product A with copper acetate, then dry at 120°C for 8h, and calcine at 400°C for 5h to obtain solid product B, so that the loading of Cu is 4% of solid product B.

[0107] (3) Dissolve 1 mol of salicylaldehyde in ethanol, add 0.5 mol of ethylenediamine ethanol solution dropwise, reflux for 1 h, cool and filter to obtain Salen ligand. Then mix 500 g of solid product B with 20 g of Salen ligand, heat at 180 °C under vacuum for 2 h, cool under nitrogen atmosphere to obtain adsorbent N6, in which the content of Y-type molecular sieve is 55.6 wt%, the content of alumina is 37 wt%, the content of Salen ligand is 3.7 wt%, and the content of Cu is 3.7 wt%.

[0108] Preparation Example 7

[0109] (1) Mix 600g of Y-type molecular sieve (silicon-to-aluminum ratio of 2.5) and 400g of alumina evenly, then add 300g of HNO3 (3%) and knead. After kneading, extrude the mixture into strips, dry it at 120℃ for 12h, and then calcine it at 400℃ for 5h to obtain solid product A.

[0110] (2) Impregnate 500g of solid product A with zinc acetate, then dry at 120°C for 8h, and calcine at 400°C for 5h to obtain solid product B, so that the zinc loading is 4% of solid product B.

[0111] (3) Dissolve 1 mol of salicylaldehyde in ethanol, add 0.5 mol of ethylenediamine ethanol solution dropwise, reflux for 1 h, cool and filter to obtain Salen ligand. Then mix 500 g of solid product B with 20 g of Salen ligand, heat at 180 °C under vacuum for 2 h, cool under nitrogen atmosphere to obtain adsorbent N7, in which the content of Y-type molecular sieve is 55.6 wt%, the content of alumina is 37 wt%, the content of Salen ligand is 3.7 wt%, and the content of Cu is 3.7 wt%.

[0112] Preparation of Comparative Example 1

[0113] (1) Mix 600g of Y-type molecular sieve (silicon-to-aluminum ratio of 2.5) and 400g of alumina evenly, then add 300g of HNO3 (3%) and knead. After kneading, extrude the mixture into strips, dry it at 120℃ for 12h, and then calcine it at 400℃ for 5h to obtain solid product A.

[0114] (2) Dissolve 1 mol of salicylaldehyde in ethanol, add 0.5 mol of ethylenediamine ethanol solution dropwise, reflux for 1 h, cool and filter to obtain Salen ligand. Then mix 500 g of solid product A with 20 g of Salen ligand, heat at 180 °C under vacuum for 2 h, cool under nitrogen atmosphere to obtain adsorbent N2, wherein the content of Y-type molecular sieve is 57.7 wt%, the content of alumina is 38.5 wt%, and the content of Salen ligand is 3.8 wt%.

[0115] Preparation of Comparative Example 2

[0116] (1) Mix 600g of Y-type molecular sieve (silicon-to-aluminum ratio of 2.5) and 400g of alumina evenly, then add 300g of HNO3 (3%) and knead. After kneading, extrude the mixture into strips, dry it at 120℃ for 12h, and then calcine it at 400℃ for 5h to obtain solid product A.

[0117] (2) Impregnate 500 g of solid product A with copper acetate, then dry at 120°C for 8 h, and calcine at 400°C for 5 h to make the Cu loading 4% of solid product B, and obtain adsorbent D2, in which the content of Y-type molecular sieve is 57.7 wt%, the content of alumina is 38.5 wt%, and the content of Cu is 3.8 wt%.

[0118] Examples 1-7

[0119] The regenerable adsorbent and the non-regenerable adsorbent of the above preparation example were packed into a fixed-bed reactor. The composition of the non-regenerable adsorbent and the loading amounts of the regenerable and non-regenerable adsorbents are listed in Table 1.

[0120] Using 200ppm CH3SH + 200ppm CH3SCH3 + 1-butene as the hydrocarbon feedstock to be purified, at room temperature and 1.5 MPa, it was purged at a weight hourly space velocity (WHSV) of 2 h⁻¹. -1 The gas passes sequentially through a first adsorbent bed containing regenerable adsorbent, followed by a second adsorbent bed containing non-regenerable adsorbent. The sulfur content in the outlet gas is determined using a sulfur-nitrogen analyzer. If the sulfur content in the outlet gas exceeds 1 ppm, it is considered adsorbent breakthrough. The sulfur breakthrough capacity of the adsorbent is calculated, and the results are listed in Table 1.

[0121] The formula for calculating sulfur penetration capacity is as follows:

[0122]

[0123] Wherein, gas flow rate is in mL / min, breakthrough time is in min, sulfur content in feed gas is in ppm, sulfur content in outlet gas is in ppm, and adsorbent weight is in g.

[0124] Comparative Example 1

[0125] The method of Example 1 is followed, except that the non-renewable adsorbent is replaced with the non-renewable adsorbent used in Comparative Example 1.

[0126] Comparative Example 2

[0127] The method of Example 1 is followed, except that the non-renewable adsorbent is replaced with the non-renewable adsorbent used in Comparative Example 2.

[0128] Table 1

[0129]

[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 method for grading adsorbents for purifying hydrocarbon feedstocks, characterized in that, The gradation method includes a renewable adsorbent and a non-renewable adsorbent arranged sequentially along the material flow direction. The non-renewable adsorbent includes a molecular sieve, a binder, a Salen ligand, and a transition metal element. Based on the total amount of the non-renewable adsorbent, the molecular sieve content is 30-80% by weight, the binder content is 5-60% by weight, the Salen ligand content is 1-8% by weight, and the transition metal element content is 1-8% by weight. The Salen ligand has the structure described in formula (1). R1 and R2 are each independently selected from H, halogen, amino, or C1-C5 alkyl groups.

2. The method according to claim 1, wherein, Based on the total amount of non-renewable adsorbent, the content of molecular sieve is 45-70% by weight, the content of binder is 25-45% by weight, the content of Salen ligand is 1.5-6% by weight, and the content of transition metal elements is 1.5-6% by weight.

3. The method according to claim 1 or 2, wherein, The molecular sieve is selected from at least one of FAU type molecular sieve, UFI type molecular sieve and MWW type molecular sieve, preferably FAU type molecular sieve; Preferably, the silicon-to-aluminum ratio of the FAU-type molecular sieve is 1-3:

1.

4. The method according to any one of claims 1-3, wherein, The transition metal element is selected from at least one of Group VIII, Group IB and Group IIB metal elements, preferably at least one of Cu, Zn, Fe, Ni and Co.

5. The method according to any one of claims 1-4, wherein, At least some of the transition metals and at least some of the Salen ligands exist in the form of transition metal complexes.

6. The method according to any one of claims 1-5, wherein, The preparation method of the non-renewable adsorbent includes: (1) Mix the molecular sieve with a binder and / or a binder precursor, then dry and calcine to obtain solid product A; (2) Introducing a transition metal element into the solid product A to obtain solid product B; (3) Mix solid product B and Salen ligand under the following conditions: temperature 150-200℃ and time 1-10 hours.

7. The method according to any one of claims 1-6, wherein, The renewable adsorbent comprises a second molecular sieve and a binder, preferably the binder being alumina; Preferably, based on the total amount of regenerable adsorbent, the content of the second molecular sieve is 50-80% by weight, and the content of the binder is 20-50% by weight. More preferably, based on the total amount of regenerable adsorbent, the content of the second molecular sieve is 55-75% by weight, and the content of the binder is 25-45% by weight. Preferably, the second molecule is selected from at least one of 3A, 4A, 5A, 13X and NaY.

8. The method according to any one of claims 1-7, wherein, The weight ratio of regenerable adsorbent to non-regenerable adsorbent is 1:(1-3), preferably 1:(1-2).

9. A method for purifying hydrocarbon feedstock, the method comprising: injecting the hydrocarbon feedstock to be purified into a purification system for adsorption under adsorption conditions, characterized in that... The adsorbent in the purification system is filled according to the adsorbent gradation method described in any one of claims 1-8; Preferably, the hydrocarbon raw material to be purified includes C4 hydrocarbons, and more preferably, it also includes sulfur-containing impurities.

10. The method according to claim 9, wherein, The hydrocarbon raw material to be purified undergoes primary adsorption using a renewable adsorbent and secondary adsorption using a non-renewable adsorbent. Preferably, the conditions for the primary and secondary adsorption independently include a weight hourly space velocity (WHSV) of 0.1-8 h⁻¹. -1 The pressure is 1-3 MPa, and the temperature is 0-40℃; Preferably, the regenerable adsorbent is regenerated after it has become saturated with adsorption. More preferably, the regeneration conditions include: a temperature of 200-350°C and a time of 2-10 hours.

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