An adsorbent for deep removal of sulfur-containing compounds from low-carbon alkanes with high CO2 content and its preparation method.

Abstract

The application provides an adsorbent for deeply removing sulfur compounds in low-carbon alkanes with high CO2 content and a preparation method thereof. The adsorbent for deeply removing sulfur compounds in low-carbon alkanes with high CO2 content comprises 70-90% of modified zeolite molecular sieve and 10-30% of a binder; wherein the modified zeolite molecular sieve is a high calcium ion exchange degree 5A molecular sieve modified by a small molecule amino silane coupling agent, and the calcium ion exchange degree of the high calcium ion exchange degree 5A molecular sieve is greater than 90%. The application takes the high calcium ion exchange degree 5A molecular sieve as an active component, when the calcium exchange degree is greater than 90%, all weakly coordinated sodium ions are removed, the reaction of H2S and CO2 in the raw material on the adsorbent to generate COS is avoided, and the desulfurization precision is improved; meanwhile, the high charge density of calcium ions can enhance the coulomb attraction with polar sulfides such as H2S and mercaptans, reduce the adsorption of weakly polar CO2 impurities, and improve the adsorption capacity and adsorption selectivity of sulfides.

Description

Technical Field

[0001] This invention relates to the field of catalysts, and more specifically to an adsorbent for the deep removal of sulfur-containing compounds from low-carbon alkanes with high CO2 content and its preparation method. Background Technology

[0002] Low-carbon alkanes (such as methane, ethane, and propane) are important chemical raw materials and clean energy sources, widely used in natural gas chemicals, petrochemicals, fuel cells, and liquefied natural gas. Naturally sourced low-carbon alkanes typically contain sulfur-containing compounds (such as hydrogen sulfide, carbonyl sulfide, and thiols) and high levels of carbon dioxide, posing a significant challenge to gas purification processes. Sulfur-containing compounds not only poison and deactivate downstream catalysts and corrode equipment, but also generate harmful gases such as sulfur dioxide during combustion or reactions, causing environmental pollution and harming human health. Simultaneously, high CO2 content competes with sulfur-containing compounds for adsorption sites, causing environmental pollution and harming human health. Therefore, developing highly efficient adsorbents capable of deeply removing sulfur-containing compounds in high CO2 atmospheres and reducing the total sulfur content to below 0.1 ppm has become a key technological bottleneck restricting the efficient utilization of low-carbon alkanes.

[0003] Currently, commonly used industrial desulfurization technologies mainly include catalytic hydrodesulfurization, oxidative desulfurization, and adsorption desulfurization. Among them, adsorption methods have attracted much attention due to their advantages such as mild operating conditions, low equipment investment, simple process flow, and no secondary pollution. Commonly used desulfurization adsorbents in industry include activated carbon, metal oxides, and molecular sieves.

[0004] Activated carbon possesses a rich pore structure, and the distribution and surface properties of this pore structure are key factors affecting its desulfurization performance. Modification of activated carbon can enhance its adsorption capacity. Activated carbon can be prepared using different raw materials and processes, and then modified to produce activated carbon desulfurizing agents suitable for removing sulfides from hydrogenated products and various gases. However, even modified activated carbon suffers from drawbacks such as low sulfur capacity, non-renewability, and susceptibility to desorption after adsorption.

[0005] Metal oxides (such as zinc oxide) exhibit significant thermodynamic advantages in their reaction with hydrogen sulfide, resulting in high desulfurization precision, making them widely used fine desulfurizing agents. Chinese patent CN103769043B discloses a gas desulfurization adsorbent, its preparation method, and its application. This adsorbent uses M41S series mesoporous materials as a carrier, zinc oxide as the active component, and adds calcium oxyacid salts and VB / VIB group metal oxides as promoters, effectively removing sulfides at high temperatures. Chinese patent CN101485954B discloses a room-temperature zinc oxide desulfurizing agent composed of 40-90% zinc oxide, 5-50% copper oxide, and 0-20% binder, efficiently removing hydrogen sulfide at room temperature. Chinese patent CN102961959B discloses a zinc oxide fine desulfurizing agent and its preparation and application method, which is formed by extruding a mixture of active zinc oxide, high-alumina powder, bentonite, calcium hydroxide, and sodium carboxymethyl cellulose. However, this type of desulfurizer usually only has an adsorption effect on hydrogen sulfide and has poor removal ability for organic sulfides such as carbonyl sulfide and mercaptan; moreover, zinc oxide desulfurizers usually need to be above 300℃ to ensure a good sulfur capacity, and the sulfur capacity decreases significantly under normal temperature and pressure conditions.

[0006] Molecular sieve desulfurization is a technology that utilizes porous materials to selectively adsorb sulfides from gases or liquids, suitable for purification processes of natural gas, refinery gas, biogas, etc. Commonly used desulfurization molecular sieves include A, X, and Y type molecular sieves, which can selectively adsorb hydrogen sulfide and polar organic sulfides based on their polarity and pore size. Deep desulfurization of low-carbon alkanes places stringent requirements on the pore structure of the adsorbent; the adsorbent must possess a microporous structure matching the molecular size of the sulfur-containing compounds, while simultaneously preventing pore blockage that could lead to adsorption capacity decay.

[0007] Type A molecular sieves have pore sizes that are highly compatible with small-molecule sulfur-containing compounds and contain abundant exchangeable cations and skeletal oxygen polar sites, making them easy to modify specifically. Theoretically, 4A molecular sieves with a pore size of 0.4 nm can adsorb small-molecule sulfur-containing compounds; however, experiments have shown that their dynamic adsorption capacity is very low. 5A molecular sieves, after calcium ion exchange, exhibit significantly improved dynamic adsorption capacity for sulfides. However, experiments have also revealed that conventional 5A molecular sieves, when used for desulfurization of low-carbon alkanes with high CO2 content, exhibit competitive adsorption of CO2, and the reaction of CO2 and H2S on the adsorbent to form COS, leading to reduced desulfurization accuracy and capacity.

[0008] Therefore, in order to address the shortcomings of existing adsorbents in the deep desulfurization of low-carbon alkanes under high CO2 atmospheres, such as poor selectivity, low desulfurization capacity, and weak resistance to CO2 interference, it is urgent to develop new adsorbents to solve the above problems. Summary of the Invention

[0009] This invention aims to address the shortcomings of existing adsorbents in the deep desulfurization of low-carbon alkanes under high CO2 atmospheres, such as poor selectivity, low desulfurization capacity, and weak resistance to CO2 interference. It proposes an adsorbent for deep removal of sulfur-containing compounds from low-carbon alkanes with high CO2 content and its preparation method.

[0010] The technical method of the present invention is as follows: An adsorbent for deep removal of sulfur-containing compounds from low-carbon alkanes with high CO2 content comprises 70%-90% by mass of modified zeolite molecular sieve and 10%-30% by mass of binder; wherein the modified zeolite molecular sieve is a 5A molecular sieve with high calcium ion exchange degree modified by a small molecule aminosilane coupling agent, and the calcium ion exchange degree of the 5A molecular sieve with high calcium ion exchange degree is greater than 90%.

[0011] Optionally, the small molecule aminosilane coupling agent includes one or more of γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, and γ-aminopropylmethyldimethoxysilane.

[0012] Optionally, the binder comprises kaolin and / or attapulgite.

[0013] Optionally, the adsorbent has a diameter of 1.5-5 mm and a compressive strength greater than 50 N / cm; when used to remove sulfur-containing compounds from low-carbon alkanes with high CO2 content, it can remove total sulfur to less than 1 ppm and has a single adsorption sulfur capacity greater than 3 wt%.

[0014] The present invention also provides a method for preparing an adsorbent for deep removal of sulfur-containing compounds from low-carbon alkanes with high CO2 content, comprising: mixing modified zeolite molecular sieves and binders, molding, drying, and calcining to obtain the adsorbent.

[0015] Optionally, the preparation of the modified zeolite molecular sieve includes: degassing 5A molecular sieve with a calcium exchange capacity greater than 90% under vacuum at 250-350℃ for 2-4 hours to remove adsorbed water and impurities, thereby obtaining a pretreated molecular sieve; mixing a small molecule aminosilane coupling agent, anhydrous ethanol, and deionized water to obtain a mixed solution; adding the pretreated molecular sieve to the mixed solution, refluxing at 60-80℃ for 4-8 hours, filtering, washing with anhydrous ethanol, drying at 110-130℃ for 1-3 hours, and calcining at 450-550℃ for 1-3 hours to obtain the modified zeolite molecular sieve.

[0016] Optionally, the preparation of the 5A molecular sieve with a calcium exchange rate greater than 90% includes: S1, mixing the 4A molecular sieve raw powder with Ca... 2+An aqueous solution was subjected to one ion exchange to obtain a low-sodium intermediate. The low-sodium intermediate was filtered, washed, dried, and calcined to obtain a 5A molecular sieve with one calcium exchange. Step S2 and S1 were repeated N times to obtain a 5A molecular sieve with a calcium exchange degree greater than 90%. The concentration of the ion exchange solution increased sequentially, but did not exceed 4.0 mol / L.

[0017] Optionally, in step S1, the concentration of the ion exchange solution is 0.5-1.5 mol / L. The solid-liquid ratio for ion exchange is 1:3-12, the temperature for ion exchange is 60-95℃, and the time for ion exchange is 2-10 h. The Ca... 2+ The aqueous solution is a calcium chloride, calcium nitrate, or calcium acetate solution.

[0018] The beneficial effects of this invention are: I. This invention uses 5A molecular sieve with high calcium ion exchange capacity as the active component. When the calcium exchange capacity is greater than 90%, all weakly coordinated sodium ions are removed, avoiding the reaction of H2S and CO2 in the raw material on the adsorbent to form COS, thus improving the desulfurization accuracy. At the same time, the high charge density of calcium ions can enhance the Coulomb attraction with polar sulfides such as H2S and thiols, reduce the adsorption of weakly polar CO2 impurities, and improve the adsorption capacity and selectivity of sulfides.

[0019] II. This invention modifies molecular sieves with small molecule aminosilane coupling agents, introduces amino functional groups, further optimizes the uniformity of polar site distribution, enhances the adsorption selectivity of adsorbents for acidic polar molecules, and weakens the adsorption of weakly polar molecules such as CO2.

[0020] Third, by adjusting the amount of modifier and the calcination temperature, this invention constructs a multi-level pore structure of "micropore-mesopore", which accelerates the diffusion of sulfide molecules and significantly improves the adsorption mass transfer rate. Detailed Implementation

[0021] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] This invention provides an adsorbent for the deep removal of sulfur-containing compounds from low-carbon alkanes with high CO2 content, comprising 70%-90% by mass of modified zeolite molecular sieve and 10%-30% by mass of binder. The modified zeolite molecular sieve is a 5A molecular sieve with high calcium ion exchange capacity modified by a small-molecule aminosilane coupling agent, wherein the calcium ion exchange capacity of the 5A molecular sieve is greater than 90%. Preferably, the mass fraction of the modified zeolite molecular sieve is 75%-85%, and the mass fraction of the binder is 15%-25%. Here, the CO2 content is greater than 0.5 mol.

[0023] In this embodiment, the small molecule aminosilane coupling agent includes one or more of γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, and γ-aminopropylmethyldimethoxysilane.

[0024] In this embodiment, the binder includes kaolin and / or attapulgite.

[0025] The adsorbent of this invention, when used to remove sulfur-containing compounds from low-carbon alkanes with high CO2 content, features high desulfurization precision, good adsorption selectivity, high adsorption capacity, and high desulfurization efficiency. The adsorbent has a diameter of 1.5-5 mm and a compressive strength greater than 50 N / cm. When used to remove sulfur-containing compounds from low-carbon alkanes with high CO2 content, it can remove total sulfur to below 1 ppm, with a single-batch sulfur adsorption capacity greater than 3 wt%.

[0026] This invention also provides a method for preparing an adsorbent for deep removal of sulfur-containing compounds from low-carbon alkanes with high CO2 content, comprising: mixing modified zeolite molecular sieves and a binder, molding, drying, and calcining to obtain the adsorbent. Here, molding is performed by extrusion or ball rolling.

[0027] In this embodiment, the preparation of the modified zeolite molecular sieve includes: A1. Degas 5A molecular sieves with a calcium exchange capacity greater than 90% under vacuum at 250-350℃ for 2-4 hours to remove adsorbed water and impurities, obtaining pretreated molecular sieves. Preferably, degassing is performed under vacuum at 300℃ for 3 hours.

[0028] A2. Mix the small molecule aminosilane coupling agent, anhydrous ethanol and deionized water to obtain a mixture.

[0029] In this embodiment, 10-30 parts (preferably 20 parts) of small molecule aminosilane coupling agent, 65-80 parts (preferably 72 parts) of anhydrous ethanol and 5-15 parts (preferably 8 parts) of deionized water are weighed and mixed.

[0030] A3. Add the pretreated molecular sieve to the mixture, reflux at 60-80℃ (preferably 65-75℃) for 4-8 hours (preferably 6 hours), filter, wash with anhydrous ethanol, dry at 110-130℃ (preferably 120℃) for 1-3 hours (preferably 2 hours), and calcine at 450-550℃ (preferably 500℃) for 1-3 hours (preferably 2 hours) to obtain the modified zeolite molecular sieve. Here, the mass ratio of the pretreated molecular sieve to the volume ratio of the mixture is 1:5-1:15 (g / ml).

[0031] In this embodiment, the sample is washed 1-5 times with anhydrous ethanol.

[0032] In this embodiment, the preparation of 5A molecular sieves with a calcium exchange rate greater than 90% includes: S1. Use Ca to process the 4A molecular sieve raw powder. 2+ An aqueous solution was subjected to a single ion exchange to obtain a low-sodium intermediate. The low-sodium intermediate was then filtered, washed, dried, and calcined to obtain a 5A molecular sieve with a single calcium exchange.

[0033] In this embodiment, the concentration of the ion exchange solution is 0.5-1.5 mol / L, preferably 0.8-1.2 mol / L.

[0034] In this embodiment, Ca 2+ The aqueous solution is a calcium chloride, calcium nitrate, or calcium acetate solution, preferably a calcium chloride solution.

[0035] In this embodiment, the ion exchange temperature is 60-95℃, preferably 80℃. The ion exchange time is 2-10h, preferably 3-6h. The drying temperature is 100-150℃, preferably 105℃. The drying time is 10-14h, preferably 12h. The calcination temperature is 500-600℃, preferably 550℃. The calcination time is 1-3h, preferably 2h.

[0036] In this embodiment, the solid-liquid ratio of ion exchange is 1:3-12, preferably 1:5-10.

[0037] S2. Repeat step S1 N times to obtain 5A molecular sieve with a calcium exchange degree greater than 90%; wherein the concentration of the ion exchange solution increases sequentially, but does not exceed 4.0 mol / L.

[0038] In this embodiment, N is a natural number, greater than or equal to 1. For example, N can be 2, 3, 4, or 5. As N increases, the concentration of the ion exchange solution increases sequentially, but does not exceed 4.0 mol / L.

[0039] In this invention, unless otherwise specified, all raw materials used in the preparation are commercially available products well known to those skilled in the art.

[0040] The present invention will be described in detail below through embodiments and experimental examples. However, these are merely examples and do not limit the present invention in any way.

[0041] Example 1 500g of 4A molecular sieve raw powder (Shanghai Jiuzhou Chemical Co., Ltd.) was weighed and added to 5L of 1mol / L CaCl2 solution. After ion exchange at 60℃ for 5h, the mixture was filtered, washed, dried at 105℃ for 12h, and calcined at 550℃ for 2h to obtain CaA-1 molecular sieve. 500g of CaA-1 molecular sieve was weighed and added to 4L of 1.5mol / L CaCl2 solution. After ion exchange at 80℃ for 5h, the mixture was filtered, washed, dried at 105℃ for 12h, and calcined at 550℃ for 2h to obtain CaA-2 molecular sieve. 500g of CaA-2 molecular sieve was weighed and added to 4L of 2mol / L CaCl2 solution. After ion exchange at 80℃ for 5h, the mixture was filtered, washed, dried at 105℃ for 12h, and calcined at 550℃ for 2h to obtain 5A molecular sieve raw powder with a calcium exchange rate greater than 90%. 5A molecular sieve raw powder with a calcium exchange rate greater than 90% was degassed under vacuum at 300℃ for 3h. 20 parts of γ-aminopropyltriethoxysilane, 72 parts of anhydrous ethanol and 8 parts of deionized water were weighed and mixed. The pretreated molecular sieve was added to the mixed solution (the mass of the pretreated molecular sieve: the volume of the mixed solution was 1:10 g / ml). The mixture was refluxed at 70℃ for 6h, filtered, washed 3 times with anhydrous ethanol, dried at 120℃ for 2h, and calcined at 500℃ for 2h to obtain the modified 5A molecular sieve. Weigh 400g of modified 5A molecular sieve powder and 100g of kaolin, mix them evenly, and place them in a kneader. After kneading evenly, place them in an extruder and extrude them into strips using a 3mm mold. After drying at 100℃ for 12h, calcine them at 550℃ for 4h to obtain the sulfide adsorbent DS-A1 of Example 1.

[0042] Comparative Example 1 Weigh 500g of 4A molecular sieve raw powder (Shanghai Jiuzhou Chemical Co., Ltd.), add it to 5L of 0.25mol / L CaCl2 solution, and after ion exchange at 60℃ for 5h, filter, wash, dry at 105℃ for 12h, and calcine at 550℃ for 2h to obtain 5A molecular sieve raw powder with calcium exchange degree less than 60%. Weigh 400g of 5A molecular sieve raw powder with a calcium exchange rate of less than 60% and 100g of kaolin, mix them evenly and place them in a kneader. After kneading evenly, place them in an extruder and extrude them into strips using a 3mm mold. After drying at 100℃ for 12h, calcine them at 550℃ for 4h to obtain the sulfide adsorbent DS-B1 of Comparative Example 1.

[0043] Comparative Example 2 500g of 4A molecular sieve raw powder (Shanghai Jiuzhou Chemical Co., Ltd.) was weighed and added to 5L of 1mol / L CaCl2 solution. After ion exchange at 60℃ for 5h, the mixture was filtered, washed, dried at 105℃ for 12h, and calcined at 550℃ for 2h to obtain CaA-1 molecular sieve. 500g of CaA-1 molecular sieve was weighed and added to 4L of 1.5mol / L CaCl2 solution. After ion exchange at 80℃ for 5h, the mixture was filtered, washed, dried at 105℃ for 12h, and calcined at 550℃ for 2h to obtain CaA-2 molecular sieve. 500g of CaA-2 molecular sieve was weighed and added to 4L of 2mol / L CaCl2 solution. After ion exchange at 80℃ for 5h, the mixture was filtered, washed, dried at 105℃ for 12h, and calcined at 550℃ for 2h to obtain 5A molecular sieve raw powder with a calcium exchange rate greater than 90%. Weigh 400g of 5A molecular sieve raw powder with a calcium exchange rate greater than 90% and 100g of kaolin, mix them evenly and place them in a kneader. After kneading evenly, place them in an extruder and extrude them into strips using a 3mm mold. After drying at 100℃ for 12h, calcine them at 550℃ for 4h to obtain the sulfide adsorbent DS-B2 of Comparative Example 2.

[0044] Example 2 500g of 4A molecular sieve raw powder (Shanghai Jiuzhou Chemical Co., Ltd.) was weighed and added to 5L of 1mol / L Ca(NO3)2 solution. After ion exchange at 70℃ for 8h, the mixture was filtered, washed, dried at 105℃ for 12h, and calcined at 550℃ for 2h to obtain CaA-1 molecular sieve. 500g of CaA-1 molecular sieve was weighed and added to 4L of 1.5mol / L Ca(NO3)2 solution. After ion exchange at 70℃ for 8h, the mixture was filtered, washed, dried at 105℃ for 12h, and calcined at 550℃ for 2h to obtain CaA-2 molecular sieve. 500g of CaA-2 molecular sieve was weighed and added to 4L of 2.5mol / L Ca(NO3)2 solution. After ion exchange at 70℃ for 8h, the mixture was filtered, washed, dried at 105℃ for 12h, and calcined at 550℃ for 2h to obtain 5A molecular sieve raw powder with a calcium exchange rate greater than 90%. 5A molecular sieve powder with a calcium exchange rate greater than 90% was degassed under vacuum at 300℃ for 3h. 22 parts of γ-aminopropyltrimethoxysilane, 70 parts of anhydrous ethanol and 8 parts of deionized water were weighed and mixed. The pretreated molecular sieve was added to the mixed solution (the mass of the pretreated molecular sieve and the volume of the mixed solution were 1:12 g / ml). The mixture was refluxed at 65℃ for 7h, filtered, washed 4 times with anhydrous ethanol, dried at 120℃ for 2h, and calcined at 500℃ for 2h to obtain the modified 5A molecular sieve. Weigh 420g of modified 5A molecular sieve powder and 80g of attapulgite, mix them evenly, and place them in a kneader. After kneading evenly, place them in an extruder and extrude them into strips using a 3mm mold. After drying at 100℃ for 12h, calcine them at 550℃ for 4h to obtain the sulfide adsorbent DS-A2 of Example 2.

[0045] To demonstrate the effectiveness of the sulfide adsorbent provided in this application, the following experiments were conducted: The sulfide adsorbents of Examples 1-2 and Comparative Examples 1-2 were tested for adsorption and desulfurization performance using a micro-evaluation device. The test conditions were 40°C, 2.0 MPa, and a space velocity of 1.6 h⁻¹. -1 The desulfurizing agent was 5g in quantity. It was first pretreated with inert gas at 350℃ for 2 hours, then cooled to room temperature before being introduced into a propane mixed solution. The sulfide impurities were hydrogen sulfide and carbonyl sulfide, with sulfur contents of 200mg / m³. 3 and 30mg / m 3 The CO2 impurity content is 200g / m³. 3 The total sulfide content at the outlet was detected by a sulfur-nitrogen analyzer. The adsorption reaction process was stopped when the total sulfur content at the outlet showed a significant jump, which was taken as one test operation cycle. The experimental results are listed in Table 1 below.

[0046] Table 1. Comparison of desulfurization adsorbents in Examples 1-2 and Comparative Examples 1-2 As shown in Table 1, compared with Comparative Examples 1-2, the sulfide adsorbents prepared in Examples 1-2 have significantly lower minimum sulfide content at the adsorption outlet, all less than 1 ppm, and higher total sulfur capacity. This indicates that the 5A molecular sieve with high calcium ion exchange capacity has low adsorption capacity for CO2 impurities, avoiding COS formation and achieving higher desulfurization precision. Furthermore, the modified adsorbent shows a significant increase in sulfide adsorption capacity, demonstrating that the sulfide adsorbents prepared in these examples possess high desulfurization precision, good adsorption selectivity, and high adsorption capacity.

[0047] Various embodiments of the present invention may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of the invention; therefore, it should be considered that the range description has specifically disclosed all possible subranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the range referred to.

[0048] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An adsorbent for deep removal of sulfur-containing compounds from low-carbon alkanes with high CO2 content, characterized in that, It includes 70%-90% modified zeolite molecular sieves and 10%-30% binder by mass; among which, The modified zeolite molecular sieve is a 5A molecular sieve with high calcium ion exchange degree modified by a small molecule aminosilane coupling agent, and the calcium ion exchange degree of the 5A molecular sieve with high calcium ion exchange degree is greater than 90%.

2. The adsorbent according to claim 1, characterized in that, The small molecule aminosilane coupling agent includes one or more of γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, and γ-aminopropylmethyldimethoxysilane.

3. The adsorbent according to claim 1, characterized in that, The binder includes kaolin and / or attapulgite.

4. The adsorbent according to claim 1, characterized in that, The adsorbent has a diameter of 1.5-5 mm and a compressive strength greater than 50 N / cm; When used to remove sulfur-containing compounds from low-carbon alkanes with high CO2 content, it can remove total sulfur to less than 1 ppm and has a single adsorption capacity of more than 3 wt%.

5. The method for preparing the adsorbent for deep removal of sulfur-containing compounds from low-carbon alkanes with high CO2 content according to any one of claims 1-4, characterized in that, include: The modified zeolite molecular sieve and binder are mixed, shaped, dried, and calcined to obtain the adsorbent.

6. The preparation method according to claim 5, characterized in that, The preparation of the modified zeolite molecular sieve includes: 5A molecular sieves with a calcium exchange rate greater than 90% were degassed under vacuum at 250-350℃ for 2-4 hours to remove adsorbed water and impurities, thus obtaining pretreated molecular sieves. A mixture of small molecule aminosilane coupling agent, anhydrous ethanol and deionized water is obtained; The pretreated molecular sieve was added to the mixture and refluxed at 60-80℃ for 4-8 hours. After filtration, it was washed with anhydrous ethanol, dried at 110-130℃ for 1-3 hours, and calcined at 450-550℃ for 1-3 hours to obtain the modified zeolite molecular sieve.

7. The preparation method according to claim 6, characterized in that, The preparation of the 5A molecular sieve with a calcium exchange rate greater than 90% includes: S1. Use Ca to process the 4A molecular sieve raw powder. 2+ An aqueous solution was subjected to a single ion exchange to obtain a low-sodium intermediate. The low-sodium intermediate was then filtered, washed, dried, and calcined to obtain a 5A molecular sieve with a single calcium exchange. S2. Repeat step S1 N times to obtain 5A molecular sieve with a calcium exchange degree greater than 90%; wherein the concentration of the ion exchange solution increases sequentially, but does not exceed 4.0 mol / L.

8. The preparation method according to claim 7, characterized in that, In step S1, the concentration of the ion exchange solution is 0.5-1.5 mol / L.

9. The preparation method according to claim 7, characterized in that, In step S1, the solid-liquid ratio of ion exchange is 1:3-12, the temperature of ion exchange is 60-95℃, and the time of ion exchange is 2-10h.

10. The preparation method according to claim 7, characterized in that, In step S1, Ca 2+ The aqueous solution is a calcium chloride, calcium nitrate, or calcium acetate solution.

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