Sulfur modified adsorbent, preparation method thereof and ethylene / ethane adsorption separation method

Abstract

The invention relates to the technical field of adsorption separation, in particular to a sulfur modified adsorbent, a preparation method thereof and an ethylene / ethane adsorption separation method. The sulfur modified adsorbent comprises a carrier and active components, part of the active components are loaded on the surface and / or inside of the carrier in the form of metal sulfide, and the remaining active components are loaded on the surface and / or inside of the carrier in the form of at least one of metal simple substances, metal oxides and metal ions; wherein in the sulfur modified adsorbent, the molar ratio of the active component to the sulfur element in terms of metal elements is (30-170): 1. According to the sulfur-modified adsorbent, the pi complexing action of the sulfur-modified adsorbent and ethylene is optimized by regulating and controlling the chemical environment of the pore channels of the adsorbent, so that the ethylene dynamic adsorption capacity and the ethylene / ethane separation factor of the sulfur-modified adsorbent are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of adsorption separation technology, and particularly relates to a sulfur-modified adsorbent, a preparation method of the sulfur-modified adsorbent, and a method for adsorption separation of ethylene / ethane. BACKGROUND

[0002] The separation and purification of ethylene is an extremely important process in the petrochemical industry. Due to the extremely similar physicochemical properties of the product ethylene and the main impurity ethane, the deep cooling rectification driven by heat is generally used for separation at present, and the equipment investment and energy consumption are extremely high. In order to implement the concept of green development, it is imperative to develop an adsorption separation technology with low energy consumption and better economy.

[0003] The adsorbent is the core of the adsorption separation technology, and directly determines the processing capacity of the separation device and the purity of the ethylene product. The ideal adsorbent should have high dynamic adsorption capacity and separation factor, and these two performances can be improved by regulating the chemical environment of the adsorbent pores.

[0004] Molecular sieves are a kind of commonly used adsorbent materials, and have a flexible and adjustable chemical environment due to a large number of balance cations in the framework. The existing technology regulates the chemical environment of the pores by introducing adsorption sites through ion exchange. The type, exchange amount and dispersion degree of the exchanged ions in the adsorbent jointly determine the adsorption separation performance. The exchanged ions are generally selected to be Ag + , Cu + with high adsorption strength, so as to obtain good separation performance. The higher the exchange amount and the better the dispersion degree, the better the separation performance. However, the higher the exchange amount, the more likely the exchange ions are to agglomerate, resulting in a significant decrease in the separation performance.

[0005] Therefore, the ion exchange technology has an upper limit for improving the separation performance of the adsorbent, and other methods for regulating the chemical environment of the adsorbent pores need to be developed. SUMMARY

[0006] The purpose of the present application is to overcome the above technical problems, and to provide a sulfur-modified adsorbent and a preparation method thereof, and a method for adsorption separation of ethylene / ethane. The sulfur-modified adsorbent regulates the chemical environment of the adsorbent pores, optimizes the π complexation with ethylene, and further improves the ethylene dynamic adsorption capacity of the sulfur-modified adsorbent and the separation factor of ethylene / ethane.

[0007] In order to achieve the above purpose, the first aspect of the present application provides a sulfur-modified adsorbent, which comprises a carrier and an active component, wherein part of the active component is loaded on the surface and / or inside of the carrier in the form of a metal sulfide, and the remaining part of the active component is loaded on the surface and / or inside of the carrier in the form of at least one of a metal element, a metal oxide and a metal ion;

[0008] In the sulfur-modified adsorbent, the molar ratio of the active component to sulfur, calculated as metal element, is 30-170:1.

[0009] The second aspect of the present invention provides a method for preparing a sulfur-modified adsorbent, the method comprising: subjecting an unmodified adsorbent to a first heating activation, then contacting it with a mixed gas containing H2S and subjecting it to sulfur treatment, such that a portion of the active component is loaded on the surface and / or interior of the support in the form of a metal sulfide, and the remaining portion of the active component is loaded on the surface and / or interior of the support in the form of at least one of a metal element, a metal oxide, and a metal ion, thereby obtaining an intermediate product which is then subjected to a second heating activation to obtain a sulfur-modified adsorbent.

[0010] The third aspect of the present invention provides a method for adsorption and separation of ethylene / ethane, wherein a feed gas containing ethylene / ethane is contacted with a sulfur-modified adsorbent provided in the first aspect, or a sulfur-modified adsorbent prepared by the preparation method provided in the second aspect, and adsorption is performed.

[0011] Compared with the prior art, the present invention has the following advantages:

[0012] (1) The sulfur-modified adsorbent provided by the present invention limits some active components to exist in the form of metal sulfides, and combines the specific molar ratio of metal elements and sulfur elements in the active components to change the chemical environment of the pores by regulating the composition of the active components, thereby enhancing the π complexation with ethylene (Ag2S has a stronger π complexation with ethylene than Ag2O because sulfur has a weaker electronegativity), thereby improving the dynamic adsorption capacity of ethylene and the separation factor of ethylene / ethane of the sulfur-modified adsorbent.

[0013] (2) The preparation method provided by the present invention optimizes the performance of the sulfur-modified adsorbent by adjusting the ratio of gas to agent in sulfur treatment and thus adjusting the proportion of metal sulfides in the sulfur-modified adsorbent. At the same time, the method also simplifies the process flow and facilitates industrial production.

[0014] (3) The sulfur-modified adsorbent provided by the present invention is used for ethylene / ethane adsorption and separation to achieve efficient separation of ethylene. Attached Figure Description

[0015] Figure 1 The X-ray diffraction patterns are those of sulfur-modified adsorbents S1-S4 prepared in Examples 1-4 and adsorbent DS1 prepared in Comparative Example 1.

[0016] Figure 2 The nitrogen adsorption curves of sulfur-modified adsorbents S1 and S4 prepared in Examples 1 and 4 and adsorbent DS1 prepared in Comparative Example 1 at 77K and saturated vapor pressure are shown.

[0017] Figure 3The X-ray photoelectron spectroscopy (XPS) fine spectrum (S2p) and peak fitting results of sulfur-modified adsorbent S4 prepared in Example 4 are shown.

[0018] Figure 4 The dynamic breakthrough curves of sulfur-modified adsorbents S1-S4 prepared in Examples 1-4 and adsorbent DS1 prepared in Comparative Example 1 for ethylene-ethane mixture at 298 K and 0.2 MPa (G) are shown. Detailed Implementation

[0019] 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.

[0020] In this invention, unless otherwise specified, "first" and "second" do not indicate a sequence or limit the specific materials or steps; they are merely used to distinguish or indicate that these are not the same material or step. For example, "first heating activation" and "second heating activation" are only used to indicate that these are not the same heating activation.

[0021] The first aspect of the present invention provides a sulfur-modified adsorbent, the sulfur-modified adsorbent comprising a support and an active component, wherein a portion of the active component is loaded on the surface and / or interior of the support in the form of a metal sulfide, and the remaining portion of the active component is loaded on the surface and / or interior of the support in the form of at least one of a metal element, a metal oxide, and a metal ion.

[0022] In the sulfur-modified adsorbent, the molar ratio of the active component to sulfur, calculated as metal element, is 30-170:1.

[0023] In this invention, unless otherwise specified, the active component consists of a partial active component and a remaining active component; at the same time, the partial active component and the remaining partial active component have the same metal element, only the metal element exists in different forms.

[0024] In some embodiments of the present invention, the molar ratio of the active component to sulfur element in the sulfur-modified adsorbent, calculated as metal element, is 30-170:1, for example, 30:1, 35:1, 38:1, 40:1, 45:1, 50:1, 60:1, 80:1, 100:1, 120:1, 150:1, 155:1, 160:1, 170:1, and any value within any range of any two values, preferably 35-155:1.

[0025] In this invention, when the above molar ratio is greater than 170:1, the content of metal sulfides is too low, and the dynamic adsorption capacity of ethylene and the ethylene / ethane separation factor of the sulfur-modified adsorbent are not significantly improved; when the above molar ratio is less than 30:1, the content of metal sulfides is too high, and the ethylene / ethane separation factor of the sulfur-modified adsorbent is significantly lower than that of the unmodified adsorbent.

[0026] In some embodiments of the present invention, preferably, the metal sulfide, calculated as SO3, accounts for 0.01wt%-0.5wt% of the total mass of the sulfur-modified adsorbent, for example, 0.01wt%, 0.05wt%, 0.08wt%, 0.1wt%, 0.15wt%, 0.2wt%, 0.25wt%, 0.3wt%, 0.5wt%, and any value within any range of any two values, preferably 0.05wt%-0.3wt%.

[0027] In this invention, unless otherwise specified, the content of the active components existing in the form of metal sulfides and the content of the remaining active components existing in at least one of the forms of elemental metals, metal oxides and metal ions are both measured by X-ray fluorescence spectroscopy (XRF).

[0028] In some embodiments of the present invention, preferably, the active component, calculated as a metal oxide, accounts for 1 wt% to 30 wt% of the total mass of the sulfur-modified adsorbent, for example, 1 wt%, 2 wt%, 5 wt%, 10 wt%, 12 wt%, 15 wt%, 16 wt%, 18 wt%, 20 wt%, 25 wt%, 30 wt%, and any value within any range of any two values, preferably 15 wt% to 20 wt%.

[0029] In this invention, the active component content calculated as metal oxide refers to the sum of the content of a portion of the active component (i.e., the modified content) and the content of the remaining portion of the active component (i.e., the unmodified content) in the sulfur-modified adsorbent.

[0030] In some embodiments of the present invention, preferably, the carrier is selected from at least one of LTA molecular sieve, FAU molecular sieve, RHO molecular sieve and CHA molecular sieve.

[0031] In one specific embodiment of the present invention, LTA-type molecular sieves include, but are not limited to, 3A molecular sieves, 4A molecular sieves, 5A molecular sieves, high-silica LTA molecular sieves, etc.; FAU-type molecular sieves include, but are not limited to, Y-type molecular sieves, etc.; RHO-type molecular sieves include, but are not limited to, SAPO-RHO molecular sieves, etc.; and CHA-type molecular sieves include, but are not limited to, SSZ-13 molecular sieves, etc.

[0032] In some embodiments of the present invention, preferably, the active metal element of the active component is a transition metal, preferably selected from at least one of manganese, iron, cobalt, nickel, copper, zinc and silver.

[0033] In this invention, the preparation method of the sulfur-modified adsorbent has a wide range of options, as long as the above limitations are met. Preferably, the sulfur-modified adsorbent is obtained by treating an unmodified adsorbent with a mixed gas containing H2S through sulfur treatment, wherein the active metal in the unmodified adsorbent is loaded on the surface and / or inside the support in the form of at least one of elemental metal, metal oxide, and metal ion.

[0034] In this invention, unless otherwise specified, compared to unmodified adsorbents, sulfur-modified adsorbents enhance the π-complexation with ethylene by changing the form of the active metal, i.e., by loading some of the active components in the form of metal sulfides onto the surface and / or interior of the carrier.

[0035] In some embodiments of the present invention, preferably, based on the total weight of the unmodified adsorbent, the content of the active metal, calculated as metal oxide, is 1wt%-30wt%, for example, 1wt%, 2wt%, 5wt%, 10wt%, 12wt%, 15wt%, 18wt%, 20wt%, 25wt%, 30wt%, and any value within any range of any two values, preferably 10wt%-20wt%.

[0036] In some embodiments of the present invention, preferably, at a temperature of 77K and a saturated vapor pressure, the specific surface area of ​​the sulfur-modified adsorbent is ≤550m². 2 / g, for example, 550m 2 / g、520m 2 / g、500m 2 / g、480m 2 / g、470m 2 / g、460m 2 / g、450m 2 / g、420m 2 / g、400m 2 / g、390m 2 / g、380m 2 / g、360m 2 / g, 350m 2 / g、320m 2 / g、300m 2 / g, and any value within the range of any two values, preferably 350-550m. 2 / g, more preferably 380-480m 2 / g.

[0037] In some embodiments of the present invention, preferably, at a temperature of 77K and a saturated vapor pressure, the pore volume of the sulfur-modified adsorbent is ≤0.210 cm³. 3 / g, for example, 0.210cm 3 / g, 0.209cm 3 / g, 0.208cm 3 / g, 0.207cm 3 / g, 0.206cm 3 / g, 0.205cm 3 / g, 0.20cm 3 / g, 0.19cm 3 / g, 0.18cm 3 / g, 0.17cm 3 / g, 0.16cm 3 / g, 0.15cm 3 / g, 0.12cm 3 / g, 0.10cm 3 / g, 0.05cm 3 / g, and any value within the range of any two values, preferably 0.10-0.208cm 3 / g, more preferably 0.15-0.208cm 3 / g.

[0038] In some embodiments of the present invention, preferably, under the conditions of a temperature of 25°C and a pressure of 0.2 MPa(G), the dynamic adsorption capacity of the sulfur-modified adsorbent for ethylene is 4.6-5 mmol / g, for example, 4.6 mmol / g, 4.7 mmol / g, 4.8 mmol / g, 4.9 mmol / g, 5 mmol / g, and any value within the range of any two values, preferably 4.8-5 mmol / g.

[0039] In some embodiments of the present invention, preferably, under the conditions of a temperature of 25°C and a pressure of 0.2 MPa(G), the ethylene / ethane separation factor of the sulfur-modified adsorbent is 3.6-10, for example, 3.6, 4, 4.2, 4.5, 4.6, 4.7, 4.8, 4.9, 5, 6, 8, 10, and any value within the range of any two values, preferably 3.6-5.

[0040] In this invention, unless otherwise specified, the dynamic adsorption capacity parameter of ethylene and the separation factor of ethylene / ethane are both measured using the two-component dynamic breakthrough curve method, the specific method of which is disclosed in the literature (Nano Res.2023,16,3536).

[0041] The second aspect of the present invention provides a method for preparing a sulfur-modified adsorbent, the method comprising: subjecting an unmodified adsorbent to a first heating activation, then contacting it with a mixed gas containing H2S and subjecting it to sulfur treatment, such that a portion of the active component is loaded on the surface and / or interior of a support in the form of a metal sulfide, and the remaining portion of the active component is loaded on the surface and / or interior of the support in the form of at least one of a metal element, a metal oxide, and a metal ion, thereby obtaining an intermediate product, which is then subjected to a second heating activation to obtain a sulfur-modified adsorbent.

[0042] In this invention, the first heating activation aims to remove adsorbed water from the unmodified adsorbent (or remove water adsorbed from the air by the unmodified adsorbent); the second heating activation aims to remove unreacted H2S. Preferably, the first heating activation and the second heating activation are each independently selected from vacuum heating activation and / or inert gas purging heating activation.

[0043] In some embodiments of the present invention, preferably, the conditions for vacuum heating activation include: a pressure of 100-1000 Pa(A), for example, 100 Pa(A), 200 Pa(A), 300 Pa(A), 400 Pa(A), 500 Pa(A), 800 Pa(A), 1000 Pa(A), and any value within the range of any two values, preferably 200-500 Pa(A).

[0044] In some embodiments of the present invention, preferably, the conditions for vacuum heating activation include: a temperature of 150-450°C, for example, 150°C, 200°C, 250°C, 300°C, 350°C, 450°C, and any value within the range of any two values, preferably 200-350°C.

[0045] In some embodiments of the present invention, preferably, the conditions for vacuum heating activation include: a time of 1-10h, for example, 1h, 2h, 5h, 6h, 8h, 10h, and any value within the range of any two values, preferably 1-5h.

[0046] In some embodiments of the present invention, preferably, the conditions for the inert gas purging and heating activation include: a pressure of 0.1-1 MPa(G), for example, 0.1 MPa(G), 0.2 MPa(G), 0.3 MPa(G), 0.4 MPa(G), 0.5 MPa(G), 0.8 MPa(G), 1 MPa(G), and any value within the range of any two values, preferably 0.1-0.5 MPa(G).

[0047] In some embodiments of the present invention, preferably, the conditions for the inert gas purging and heating activation include: a temperature of 150-450°C, for example, 150°C, 200°C, 250°C, 300°C, 350°C, 450°C, and any value within the range of any two values, preferably 200-350°C.

[0048] In some embodiments of the present invention, preferably, the conditions for the inert gas purging and heating activation include: a time of 1-10h, for example, 1h, 2h, 5h, 6h, 8h, 10h, and any value within the range of any two values, preferably 1-5h.

[0049] In this invention, unless otherwise specified, inert gases include, but are not limited to, nitrogen, helium, argon, etc.

[0050] In some embodiments of the present invention, preferably, the H2S concentration in the H2S-containing mixed gas is 50ppmv-2000ppmv, for example, 50ppmv, 100ppmv, 200ppmv, 300ppmv, 500ppmv, 800ppmv, 1000ppmv, 1500ppmv, 2000ppmv, and any value within the range of any two values, preferably 50ppmv-1000ppmv.

[0051] In this invention, 1 ppm = 1 × 10 -6 .

[0052] In this invention, the H2S-containing mixed gas may contain other components besides H2S gas. Preferably, the H2S-containing mixed gas further includes at least one of helium, nitrogen, methane, ethane, and ethylene.

[0053] In this invention, the sulfur treatment aims to contact the unmodified adsorbent after the first heating activation with a mixed gas containing H2S, so that some of the active components are modified by sulfur, resulting in metal sulfides loaded on the surface and / or inside the support.

[0054] In some embodiments of the present invention, preferably, the conditions for sulfur treatment include: a purging temperature of 10-100°C, for example, 10°C, 15°C, 20°C, 30°C, 50°C, 60°C, 80°C, 100°C, and any value within a range of any two values, preferably 15-80°C.

[0055] In some embodiments of the present invention, preferably, the conditions for sulfur treatment include: a pressure of 0.05-1 MPa(G), for example, 0.05 MPa(G), 0.1 MPa(G), 0.15 MPa(G), 0.2 MPa(G), 0.25 MPa(G), 0.3 MPa(G), 0.5 MPa(G), 0.8 MPa(G), 1 MPa(G), and any value within a range of any two values, preferably 0.1-0.5 MPa(G).

[0056] In some embodiments of the present invention, preferably, the gas-to-adsorbent ratio of the H2S-containing mixed gas and the unmodified adsorbent, calculated as H2S, is 0.05-3 mL / g, for example, 0.05 mL / g, 0.1 mL / g, 0.15 mL / g, 0.2 mL / g, 0.25 mL / g, 0.3 mL / g, 0.5 mL / g, 0.6 mL / g, 0.8 mL / g, 1 mL / g, 1.5 mL / g, 2 mL / g, 3 mL / g, and any value within any range of any two values, preferably 0.1-0.6 mL / g.

[0057] In this invention, the gas-to-adsorbent ratio refers to the amount of the H2S-containing mixed gas, calculated as H2S, used relative to 1g of unmodified adsorbent, which is 0.05-3mL, preferably 0.1-0.6mL.

[0058] In this invention, when the gas-to-adsorbent ratio is >3 mL / g, the sulfur treatment is too severe, the metal sulfide content is too high, and the ethylene / ethane separation factor of the sulfur-modified adsorbent decreases compared to the unmodified adsorbent; when the gas-to-adsorbent ratio is <0.05 mL / g, the sulfur treatment is too mild, the metal sulfide content is too low, and the dynamic adsorption capacity of ethylene and the ethylene / ethane separation factor of the sulfur-modified adsorbent do not show significant improvement.

[0059] The third aspect of the present invention provides a method for adsorption and separation of ethylene / ethane, wherein a feed gas containing ethylene / ethane is contacted with a sulfur-modified adsorbent provided in the first aspect, or a sulfur-modified adsorbent prepared by the preparation method provided in the second aspect, and adsorption is performed.

[0060] In some embodiments of the present invention, preferably, the adsorption conditions include: a temperature of 10-55°C, for example, 10°C, 20°C, 25°C, 30°C, 40°C, 50°C, 55°C, and any value within the range of any two values, preferably 20-50°C; and a pressure of 0.05-1 MPa(G), for example, 0.05 MPa(G), 0.1 MPa(G), 0.2 MPa(G), 0.4 MPa(G), 0.5 MPa(G), 0.8 MPa(G), 1 MPa(G), and any value within the range of any two values, preferably 0.1-0.5 MPa(G).

[0061] In some embodiments of the present invention, preferably, the volume fraction ratio of ethylene to ethane in the feed gas is 1-99:99-1, for example, 1:99, 5:95, 10:90, 1:49, 20:80, 40:60, 50:50, 55:45, 60:40, 80:20, 90:10, 95:5, 9:1, 99:1, and any value within the range of any two values, preferably 2:3-3:2.

[0062] According to a particularly preferred embodiment of the present invention, a sulfur-modified adsorbent comprises a support and an active component, wherein a portion of the active component is loaded on the surface and / or interior of the support in the form of a metal sulfide, and the remaining portion of the active component is loaded on the surface and / or interior of the support in the form of at least one of a metal element, a metal oxide, and a metal ion.

[0063] In the sulfur-modified adsorbent, the molar ratio of the active component to sulfur (calculated as metal element) is 35-155:1; the metal sulfide (calculated as SO3) accounts for 0.05wt%-0.3wt% of the total mass of the sulfur-modified adsorbent.

[0064] The sulfur-modified adsorbent is obtained by treating an unmodified adsorbent with a mixed gas containing H2S through sulfur treatment. The active metal in the unmodified adsorbent is loaded on the surface and / or inside the support in the form of at least one of elemental metal, metal oxide and metal ion.

[0065] The H2S-containing mixed gas has an H2S concentration of 50 ppmv-200 ppmv; the gas-to-adsorbent ratio of the H2S-containing mixed gas to the unmodified adsorbent is 0.1-0.6 mL / g; and the sulfur treatment conditions include a purging temperature of 15-80℃ and a pressure of 0.1-0.5 MPa(G).

[0066] The present invention will be described in detail below through embodiments.

[0067] Unmodified adsorbents were prepared according to the method disclosed in the literature (ACS Appl. Nano Mater. 2023, 6, 5374-5383.):

[0068] One part by mass of commercial 5A molecular sieve (NKC, China) and ten parts by mass of 0.15M silver nitrate (Sigma-Aldrich, >99%) aqueous solution were mixed and stirred at 25°C and 500 rpm for 1 h. The precipitate was then recovered by filtration, washed with deionized water to remove nitrate ions, and dried at 80°C for 12 h to obtain Ag-5A molecular sieve as an unmodified adsorbent.

[0069] Based on the total weight of the unmodified adsorbent, the Ag content, calculated as Ag₂O, is 16.0000 wt%.

[0070] The unmodified adsorbent was pressurized at 10 MPa(G) for 1 minute, crushed, and sieved to obtain particles with a diameter of 0.4-0.9 mm. 5 g of these particles were packed into a 316L stainless steel adsorption column with an inner diameter of 9 mm, and the two ends of the column were secured with quartz wool. The first heating activation was performed using nitrogen purging and heating at a pressure of 0.1 MPa(G), a temperature of 300℃, and a time of 3 hours. The adsorbent was then cooled to 25℃ for later use.

[0071] Example 1

[0072] The unmodified adsorbent in the above adsorption column was subjected to sulfur treatment using a mixed gas (H2S and ethane) with a H2S concentration of 100 ppmv. The purging temperature was 25°C and the pressure was 0.2 MPa(G). The gas-to-adsorbent ratio of the mixed gas to the unmodified adsorbent, based on H2S, was 0.28 mL / g, to obtain the intermediate product.

[0073] The above intermediate product was subjected to a second heating activation by nitrogen purging and heating activation, wherein the pressure was 0.1 MPa (G), the temperature was 300 °C, and the time was 3 h; after cooling to 25 °C, sulfur-modified adsorbent S1 was obtained.

[0074] Example 2

[0075] The method is the same as in Example 1, except that...

[0076] The gas-to-adsorbent ratio of the above mixed gas (calculated as H2S) and the unmodified adsorbent was replaced with 0.58 mL / g;

[0077] Under the same conditions, sulfur-modified adsorbent S2 was obtained.

[0078] Example 3

[0079] The method is the same as in Example 1, except that...

[0080] The gas-to-adsorbent ratio of the above mixed gas (calculated as H2S) and the unmodified adsorbent was replaced with 1.18 mL / g;

[0081] Under the same conditions, sulfur-modified adsorbent S3 was obtained.

[0082] Example 4

[0083] The method is the same as in Example 1, except that...

[0084] The gas-to-adsorbent ratio of the above mixed gas (calculated as H2S) and the unmodified adsorbent was replaced with 1.99 mL / g;

[0085] Under the same conditions, sulfur-modified adsorbent S4 was obtained.

[0086] Comparative Example 1

[0087] The method is the same as in Example 1, except that...

[0088] Without a sulfur treatment process, a second heating activation is performed directly to obtain the adsorbent DS1.

[0089] The X-ray diffraction patterns of the sulfur-modified adsorbents S1-S4 prepared in Examples 1-4 and the adsorbent DS1 prepared in Comparative Example 1 are shown below. Figure 1 The XRD diffraction patterns of sulfur-modified adsorbents S1-S4 and adsorbent DS1 are shown in the figure. Figure 1 The result indicates that the crystal phase of the adsorbent did not change after sulfur modification.

[0090] The nitrogen adsorption curves of sulfur-modified adsorbents S1 and S4 prepared in Examples 1 and 4, and adsorbent DS1 prepared in Comparative Example 1 at 77 K and saturated vapor pressure are shown below. Figure 2 As shown, the adsorption curves of all samples exhibit typical Type I characteristics, indicating that they are mainly microporous. Compared with adsorbent DS1, the nitrogen adsorption capacity of sulfur-modified adsorbents S1 and S4 is significantly lower.

[0091] Table 1

[0092] BET method for calculating specific surface area, m 2 / g]] DFT method to calculate pore volume, cm3 / g 3 / g]]> Comparative Example 1 574.63 0.2103 Example 1 474.88 0.2072 Example 4 380.74 0.1744

[0093] As shown in Table 1, compared with the adsorbent DS1 in Comparative Example 1, the sulfur-modified adsorbents prepared in Examples 1 and 4 have lower specific surface areas and pore volumes, which gradually decrease with the increase of the sulfur-treated gas-to-adsorbent ratio. This indicates that sulfur treatment locally reduces the pore size, possibly because sulfur with a larger ionic radius (assuming that the sulfur modification is entirely used to form Ag2S, an ionic compound) partially replaces oxygen.

[0094] The XRF results of sulfur-modified adsorbents S1-S4 prepared in Examples 1-4 and adsorbent DS1 prepared in Comparative Example 1 are shown in Table 2; the converted elemental molar ratios are shown in Table 3.

[0095] Table 2

[0096]

[0097]

[0098] Note: 1- The content of all sulfur elements in the sulfur-modified adsorbent / adsorbent, calculated as SO3, or the content of Ag2S in the sulfur-modified adsorbent / adsorbent, calculated as Ag2O; 2- The content of all silver elements in the sulfur-modified adsorbent / adsorbent, calculated as Ag2O.

[0099] Table 3

[0100] Elemental molar ratio Si / Al Ag / Si Ag / S Comparative Example 1 0.8921 0.2546 - Example 1 0.9386 0.2362 151.11 Example 2 0.9256 0.25 101.36 Example 3 0.9324 0.2313 43 Example 4 0.9326 0.2311 38.114

[0101] As shown in Table 2, sulfur was not detected in Comparative Example 1 without sulfur treatment, while sulfur (calculated as SO3) was detected in Examples 1-4 with sulfur treatment. Furthermore, the mass percentage increased with the increase of the sulfur treatment gas-to-adsorbent ratio, indicating that sulfur treatment successfully introduced sulfur into the adsorbent. The sulfur content in the sulfur-modified adsorbent can be controlled by the sulfur treatment gas-to-adsorbent ratio, and the two are positively correlated.

[0102] As shown in Table 3, all samples have similar Si / Al and Ag / Si ratios, indicating that the composition of the adsorbent molecular sieve framework did not change significantly before and after sulfur treatment. This suggests that the changes in the dynamic adsorption capacity and separation factor of ethylene in Examples 1-4 were due to the introduction of sulfur. Only Examples 1-4 contained sulfur, and the Ag / S ratio was much greater than 2, indicating that even according to the theoretical Ag₂S molar ratio, most of the Ag did not form Ag₂S.

[0103] The fine S2p X-ray photoelectron spectroscopy (XPS) spectrum and peak fitting results of the sulfur-modified adsorbent S4 prepared in Example 4 are as follows: Figure 3 As shown, the S2p peak belongs to Ag2S, indicating that after sulfur treatment, sulfur mainly exists in the form of Ag2S in the sulfur-modified adsorbent.

[0104] Test case

[0105] Using an ethylene-ethane (50 vol% - 50 vol%) mixture as raw material, the dynamic breakthrough curves of Examples 1-4 and Comparative Example 1 were tested at 298 K and 0.2 MPa (G). The results are as follows: Figure 4 As shown, after sulfur treatment, the breakthrough times of both ethane and ethylene increased, indicating that sulfur treatment improved the dynamic adsorption capacity of the adsorbent.

[0106] The dynamic adsorption capacity and separation factor of Examples 1-4 and Comparative Example 1, calculated from the breakthrough experiment, are detailed in Table 4.

[0107] Table 4

[0108]

[0109] Note: The rate of change of dynamic adsorption capacity of 3-ethylene is equal to the ratio of the specific value in this example to the value in Comparative Example 1; the rate of change of separation factor of 4-ethylene / ethane is equal to the ratio of the specific value in this example to the value in Comparative Example 1.

[0110] As shown in Table 4, compared to Comparative Example 1 without sulfur treatment, the sulfur-modified adsorbents prepared by the method provided in Examples 1-4 all exhibited higher dynamic adsorption capacities for ethylene than Comparative Example 1, indicating that sulfur treatment is beneficial for improving the dynamic adsorption capacity of the adsorbent. With the increase of the sulfur-treated gas-to-adsorbent ratio, the rate of change in ethylene dynamic adsorption capacity showed a trend of first increasing and then decreasing. When the sulfur-treated gas-to-adsorbent ratio reached 0.58 mL / g, the dynamic adsorption capacity of ethylene in Example 2 reached its maximum value of 4.91 mmol / g, which is 108.3% of that of Comparative Example 1 without sulfur treatment. This indicates that an excessively high sulfur-treated gas-to-adsorbent ratio is not conducive to improving the dynamic adsorption capacity of ethylene.

[0111] Examples 1-2, using the sulfur-modified adsorbents prepared by the method provided in this invention, all exhibited ethylene / ethane separation factors greater than those of Comparative Example 1. When the sulfur-treated gas-to-adsorbent ratio reached 0.28 mL / g, the ethylene / ethane separation factor in Example 1 reached its maximum value of 3.75, which is 105.5% of that in Comparative Example 1 without sulfur treatment. When the sulfur-treated gas-to-adsorbent ratio was further increased to 0.58 mL / g, the ethylene / ethane separation factor in Example 2 decreased to 3.64, which is 102.6% of that in Comparative Example 1 before sulfur treatment. When the sulfur-treated gas-to-adsorbent ratio was increased to 1.18 mL / g, the ethylene / ethane separation factor in Example 3 decreased to 3.33, which is 93.8% of that in Comparative Example 1 before sulfur treatment. When the sulfur-treated gas-to-adsorbent ratio was increased to 1.99 mL / g, the ethylene / ethane separation factor in Example 4 decreased to 3.38, which is 95.3% of that in Comparative Example 1 before sulfur treatment.

[0112] Taking into account both the dynamic adsorption capacity and separation factor of ethylene, the sulfur treatment gas-to-agent ratios are 0.28 mL / g and 0.58 mL / g, respectively. Both have similar dynamic adsorption capacities of ethylene, but the former has a larger dynamic adsorption capacity of ethylene, indicating that the sulfur treatment gas-to-agent ratio of 0.28 mL / g is the preferred condition.

[0113] 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 sulfur-modified adsorbent, characterized in that, The sulfur-modified adsorbent comprises a support and an active component, wherein a portion of the active component is loaded on the surface and / or interior of the support in the form of a metal sulfide, and the remaining portion of the active component is loaded on the surface and / or interior of the support in the form of at least one of a metal element, a metal oxide, and a metal ion. In the sulfur-modified adsorbent, the molar ratio of the active component to sulfur, calculated as metal element, is 30-170:

1.

2. The sulfur-modified adsorbent according to claim 1, wherein, In the sulfur-modified adsorbent, the molar ratio of the active component to sulfur, calculated as metal element, is 35-155:

1. And / or, the metal sulfide, calculated as SO3, accounts for 0.01wt%-0.5wt% of the total mass of the sulfur-modified adsorbent, preferably 0.05wt%-0.3wt%. And / or, the active component, calculated as metal oxide, accounts for 1 wt% to 30 wt% of the total mass of the sulfur-modified adsorbent, preferably 15 wt% to 20 wt%. And / or, the support is selected from at least one of LTA molecular sieves, FAU molecular sieves, RHO molecular sieves and CHA molecular sieves; And / or, the active metal element of the active component is a transition metal, preferably selected from at least one of manganese, iron, cobalt, nickel, copper, zinc and silver.

3. The sulfur-modified adsorbent according to claim 1 or 2, wherein, The sulfur-modified adsorbent is obtained by treating an unmodified adsorbent with a mixed gas containing H2S through sulfur treatment, wherein the active metal in the unmodified adsorbent is loaded on the surface and / or inside the support in the form of at least one of elemental metal, metal oxide and metal ion; Preferably, based on the total weight of the unmodified adsorbent, the content of the active metal, calculated as metal oxide, is 1 wt%-30 wt%, more preferably 10 wt%-20 wt%.

4. The sulfur-modified adsorbent according to any one of claims 1-3, wherein, Under conditions of 25°C and 0.2 MPa(G), the dynamic adsorption capacity of the sulfur-modified adsorbent for ethylene is 4.6-5 mmol / g, preferably 4.8-5 mmol / g. And / or, under conditions of a temperature of 25°C and a pressure of 0.2 MPa(G), the ethylene / ethane separation factor of the sulfur-modified adsorbent is 3.6-10, preferably 3.6-5.

5. A method for preparing a sulfur-modified adsorbent, characterized in that, The preparation method includes: first heating and activating the unmodified adsorbent, then contacting it with a mixed gas containing H2S and treating it with sulfur, so that some active components are loaded on the surface and / or inside the support in the form of metal sulfides, and the remaining active components are loaded on the surface and / or inside the support in the form of at least one of elemental metal, metal oxide and metal ion, and the intermediate product is then subjected to a second heating and activation to obtain a sulfur-modified adsorbent.

6. The preparation method according to claim 5, wherein, The first heating activation and the second heating activation are each independently selected from vacuum heating activation and / or inert gas purging heating activation; Preferably, the conditions for vacuum heating activation include: a pressure of 100-1000 Pa(A), preferably 200-500 Pa(A); a temperature of 150-450℃, preferably 200-350℃; and a time of 1-10 h, preferably 1-5 h. Preferably, the conditions for inert gas purging and heating activation include: pressure of 0.1-1 MPa(G), preferably 0.1-0.5 MPa(G); temperature of 150-450℃, preferably 200-350℃; and time of 1-10 h, preferably 1-5 h.

7. The preparation method according to claim 5 or 6, wherein, The H2S-containing mixed gas has an H2S concentration of 50ppmv-2000ppmv, preferably 50ppmv-1000ppmv; Preferably, the H2S-containing gas mixture further includes at least one of helium, nitrogen, methane, ethane, and ethylene.

8. The preparation method according to any one of claims 5-7, wherein, The conditions for sulfur treatment include: a purging temperature of 10-100℃, preferably 15-80℃; and a pressure of 0.05-1MPa(G), preferably 0.1-0.5MPa(G). Preferably, the gas-to-adsorbent ratio of the H2S-containing mixed gas and the unmodified adsorbent, calculated as H2S, is 0.05-3 mL / g, more preferably 0.1-0.6 mL / g.

9. A method for ethylene / ethane adsorption separation, characterized in that, The feed gas containing ethylene / ethane is contacted with the sulfur-modified adsorbent according to any one of claims 1-4, or the sulfur-modified adsorbent prepared by the preparation method according to any one of claims 5-8, and adsorption is carried out.

10. The method according to claim 9, wherein, The adsorption conditions include: a temperature of 10-55℃, preferably 20-50℃; and a pressure of 0.05-1MPa(G), preferably 0.1-0.5MPa(G). And / or, in the feed gas, the volume fraction ratio of ethylene to ethane is 1:99-99:1, preferably 2:3-3:2.

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