Adsorbent for removing trace ethane impurities in ethylene as well as preparation method and application of adsorbent

Abstract

The invention belongs to the technical field of gas separation and purification, and particularly relates to an adsorbent for removing trace ethane impurities in ethylene as well as a preparation method and application of the adsorbent. The adsorbent is mainly prepared from a metal chloride and an organic ligand, the metal chloride is one or more of zinc chloride, copper chloride and nickel chloride, and the organic ligand is 1, 2, 4-triazole. The preparation method of the adsorbent comprises the following steps: (1) adding a metal chloride and an organic ligand into water, stirring to form a dispersed muddy solid, standing for aging, and washing to obtain an adsorbent precursor; and (2) uniformly mixing the adsorbent precursor with kaolin clay and sesbania powder to form plastic slurry, and drying, crushing and sieving the plastic slurry to obtain the adsorbent for removing trace ethane impurities in ethylene. The adsorbent is simple in preparation method and high in separation selectivity, the selectivity coefficient is larger than or equal to 48, the highest selectivity coefficient can reach 119, and ethane impurity gas in raw material gas can be directly and selectively removed.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of gas separation and purification, and particularly relates to an adsorbent for removing trace ethane impurities in ethylene as well as a preparation method and application thereof. BACKGROUND

[0002] Ethylene is a key raw material for petroleum chemical industry and electronic semiconductor industry, and the purity of ethylene directly affects the performance of downstream products. Electronic-grade ethylene requires a purity of more than 99.999%, while the purity of industrial-grade ethylene is usually 99.5%-99.9%, mainly containing ethane impurities with the same carbon number.

[0003] Traditional purification methods mostly use low-temperature rectification or solvent extraction, which have problems such as high energy consumption, complex equipment, and large operation cost. For example, although a multi-stage rectification tower series process can realize high-purity separation, the number of theoretical trays is large, and the reflux ratio is large, which leads to significant energy consumption. In addition, the molecular size and boiling point of ethane and ethylene are similar, and the separation is difficult. In existing adsorption separation technologies, molecular sieves generally have low selectivity for ethylene / ethane separation, high regeneration temperature, and poor cycle performance, which are difficult to meet the electronic-grade purity requirements. Although some metal-organic framework materials have high selectivity, they are high in cost and poor in stability, and are suitable for adsorbing acetylene or carbon dioxide, but not ethane impurities. Therefore, it is urgent to develop an efficient and low-energy-consumption ethane selective adsorbent and a matching device. SUMMARY

[0004] In view of the problems and deficiencies in the prior art, the purpose of the present application is to provide an adsorbent for removing trace ethane impurities in ethylene as well as a preparation method and application thereof.

[0005] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows: The first aspect of the present application provides an adsorbent for removing trace ethane impurities in ethylene, which is mainly made of metal chlorides and organic ligands, wherein the metal chlorides are one or more of zinc chloride, copper chloride and nickel chloride, and the organic ligand is 1,2,4-triazole.

[0006] The second aspect of the present application provides a preparation method of the adsorbent for removing trace ethane impurities in ethylene according to the first aspect, which comprises the following steps: (1) adding metal chlorides and organic ligands into water, stirring to form a dispersed mud-like solid, standing for 1-3 hours, and washing to obtain an adsorbent precursor; (2) mixing the adsorbent precursor prepared in step (1) with kaolin clay and sesbania powder uniformly to form a plastic slurry, drying, crushing and sieving the plastic slurry to obtain the adsorbent for removing trace ethane impurities in ethylene.

[0007] Preferably, in step (1), the mass ratio of metal chloride to organic ligand is (0.5-2):(1-3).

[0008] Preferably, in step (2), the mass ratio of the adsorbent precursor to kaolin clay and guar gum powder is (0.6-1.8):(0.1-1.2):(0.01-0.18).

[0009] Preferably, the stirring temperature in step (1) is 10-30°C and the stirring time is 20-60 min.

[0010] Preferably, the drying temperature in step (2) is 60-80°C and the drying time is 2-10 h.

[0011] Preferably, the number of washing cycles in step (1) is 2 to 8.

[0012] Preferably, the crushed material in step (2) is passed through an 8*30 mesh standard sieve.

[0013] A third aspect of the present invention provides an application of the adsorbent described in the first aspect in removing trace amounts of ethane impurities from ethylene.

[0014] Preferably, the method includes the following steps: passing ethylene feed gas containing ethane impurities into an adsorption bed containing adsorbent for adsorption, and obtaining ethylene product after adsorption is completed.

[0015] Preferably, the mass ratio of raw gas to adsorbent is (5-30):(1-3), and the gas flow rate is adjusted to 5-20 L / min.

[0016] Preferably, the inlet pressure of the raw gas is 0.2-0.5 MPa and the temperature is 20-40°C.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The present invention can synthesize high-performance adsorbent materials by simple room temperature stirring. The preparation process does not require high temperature and high pressure, the operation is safe and environmentally friendly. All raw materials are conventional industrial products, the cost is low, and it has significant prospects for industrial application.

[0018] (2) The adsorbent material prepared by the present invention has high separation selectivity, with a selectivity coefficient ≥48 and up to 119. It can directly and selectively remove ethane impurity gas from the raw material gas while retaining high-purity ethylene product gas, and the product can be obtained in one step.

[0019] (3) This invention uses an adsorption bed for adsorption, which results in a fast production speed. Continuous production can be achieved through rapid switching of the adsorption bed and vacuum regeneration technology. Furthermore, the pressure swing adsorption equipment is modularly designed, allowing for different separation purposes by changing the type of adsorbent, thus offering high adjustability. The resulting product gas can be used as electronic-grade ethylene product gas that meets national standards, or as raw material gas for further purification, effectively reducing the theoretical plate number required for subsequent distillation. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the pressure swing adsorption device of the present invention; In the diagram: raw material gas tanks 11 and 12; flow meter 2; adsorption beds 31, 32 and 33; buffer tank 4; vacuum pump 5; storage tank 6; and exhaust gas treatment device 7. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0022] Example 1: An adsorbent for removing trace amounts of ethane impurities from ethylene, the specific preparation steps of which are as follows: (1) Weigh 100g of raw materials according to the mass ratio of copper chloride, 1,2,4-triazole and water of 1:1.5:3. Mix the raw materials and stir at 25℃ for 40 min to form a dispersed mud-like solid. Let it stand for 2 h to age. Wash the aged product with deionized water 4 times to obtain the adsorbent precursor. (2) The adsorbent precursor prepared in step (1) is mixed with halloysite nanoclay and guar powder at a mass ratio of 1:0.25:0.02 to form a plastic slurry. The plastic slurry is placed in a vacuum drying oven at 70℃ and dried for 8 hours. The dried solid is mechanically crushed and passed through an 8*30 mesh standard sieve to obtain an adsorbent for removing trace amounts of ethane impurities from ethylene.

[0023] Example 2: An adsorbent for removing trace amounts of ethane impurities from ethylene is basically the same as that in Example 1, except that in step (1), copper chloride is replaced with zinc chloride.

[0024] Example 3: An adsorbent for removing trace amounts of ethane impurities from ethylene is basically the same as that in Example 1, except that in step (1), copper chloride is replaced with nickel chloride.

[0025] Example 4: An adsorbent for removing trace amounts of ethane impurities from ethylene is basically the same as that in Example 1, except that in step (1), copper chloride is replaced with a metal chloride combination of zinc chloride and copper chloride in a mass ratio of 1:1.

[0026] Example 5: An adsorbent for removing trace amounts of ethane impurities from ethylene is basically the same as that in Example 1, except that in step (1), copper chloride is replaced with a combination of metal chlorides, zinc chloride and nickel chloride mixed in a mass ratio of 1:1.

[0027] Example 6: An adsorbent for removing trace amounts of ethane impurities from ethylene is basically the same as that in Example 1, except that in step (1), copper chloride is replaced with a metal chloride combination of nickel chloride and copper chloride in a mass ratio of 1:1.

[0028] Example 7: An adsorbent for removing trace amounts of ethane impurities from ethylene is basically the same as that in Example 1, except that in step (1), copper chloride is replaced with a combination of zinc chloride, copper chloride and nickel chloride mixed in a mass ratio of 1:1:1.

[0029] Example 8: An adsorbent for removing trace amounts of ethane impurities from ethylene is basically the same as that in Example 1, except that the mass ratio of copper chloride, 1,2,4-triazole and water in the raw materials in step (1) is 0.5:1.5:3.

[0030] Example 9: An adsorbent for removing trace amounts of ethane impurities from ethylene is basically the same as that in Example 1, except that the mass ratio of copper chloride, 1,2,4-triazole and water in the raw materials in step (1) is 2:1.5:3.

[0031] Example 10: An adsorbent for removing trace amounts of ethane impurities from ethylene is basically the same as in Example 1, except that in step (1), copper chloride is replaced with zinc chloride, and the mass ratio of zinc chloride, 1,2,4-triazole and water is 0.5:1.5:3.

[0032] Example 11: An adsorbent for removing trace amounts of ethane impurities from ethylene is basically the same as that in Example 1, except that in step (1), copper chloride is replaced with zinc chloride, and the mass ratio of zinc chloride, 1,2,4-triazole and water is 2:1.5:3.

[0033] Example 12: An adsorbent for removing trace amounts of ethane impurities from ethylene is basically the same as in Example 1, except that in step (1), copper chloride is replaced with nickel chloride, and the mass ratio of nickel chloride, 1,2,4-triazole and water is 0.5:1.5:3.

[0034] Example 13: An adsorbent for removing trace amounts of ethane impurities from ethylene is basically the same as that in Example 1, except that in step (1), copper chloride is replaced with nickel chloride, and the mass ratio of nickel chloride, 1,2,4-triazole and water is 2:1.5:3.

[0035] Comparative Example 1: Commercial molecular sieve catalyst 13X (purchased from Sigma-Aldrich, particle size 8-12 mesh) was used as the adsorbent.

[0036] To verify the adsorption performance of the adsorbent of this invention, the following methods were used: Figure 1 The pressure swing adsorption (PSA) device was used for adsorption performance testing. According to the material flow direction, the PSA device includes, in sequence, raw material gas tanks 11 and 12, a flow meter 2, three parallel adsorption beds 31, 32, and 33, a buffer tank 4, a vacuum pump 5, and a storage tank 6. The bottom outlets of the three parallel adsorption beds 31, 32, and 33 are connected to a tail gas treatment device 7. Control valves are connected to the outlets of the raw material gas tanks 11 and 12, and control valves are connected to the top inlets of the adsorption beds 31, 32, and 33. Control valves are also connected to two parallel pipelines connected to the bottom outlets of the adsorption beds 31, 32, and 33. At least two adsorption beds 31, 32, and 33 are kept on standby, with one operating. The adsorption beds 31, 32, and 33 are filled with the adsorbent material prepared according to the embodiments of this invention. The specific testing method is as follows: The adsorbents of Examples 1-12 of this invention and 100g of 13X molecular sieve of Comparative Example 1 were respectively loaded into the adsorption bed of a pressure swing adsorption (PSA) device, followed by nitrogen purging and activation treatment. Then, a mixed gas feed containing 0.5% ethane (volume fraction) and 99.5% ethylene was introduced into the adsorption bed at 20°C, 0.5 MPa, and a gas flow rate of 20 L / min for adsorption. After adsorption and separation in the adsorption bed, the gas was transported to a storage tank by a vacuum pump. During this process, ethane impurities were removed to below 1 ppm. The resulting tailings... The ratio of ethylene adsorption capacity and the concentration of residual ethane in the product gas after adsorption are shown in Table 1.

[0037] Table 1 Performance test results of Examples 1-12 and Comparative Example 1 As shown in Table 1, the adsorbents in Examples 1 through 13 all exhibited superior adsorption performance compared to the 13X molecular sieve in Comparative Example 1. Examples 1 through 3 used single metal salts copper chloride, zinc chloride, and nickel chloride, respectively, and the adsorption performance decreased in the following order: Example 1 > Example 2 > Example 3. This is mainly attributed to Cu... 2+ It can form an adsorption site with 1,2,4-triazole with suitable pore size, exhibiting a stronger electrostatic attraction to ethane molecules and facilitating rapid adsorption-desorption processes, thus achieving a balance between high adsorption capacity, high selectivity, and good regenerability. In contrast, Zn... 2+ with Ni 2+ The formation of sites with weak attraction to ethane resulted in a sequential decrease in overall adsorption performance, indicating that the type of central metal ion is a key factor affecting performance. Example 1 showed the best performance, with a selectivity coefficient as high as 120, and was able to remove ethane to below 1 ppm, obtaining high-purity ethylene with ≥99.999% purity.

[0038] The adsorption performance of the mixtures of two or three metal salts in Examples 4 to 7 was generally between that of the single metal salts, and failed to show a synergistic effect. Moreover, the performance of each of them did not exceed that of Example 1.

[0039] Examples 8-13 varied the mass ratio of the metal salt to the organic ligand. The results showed that the mass ratio of the metal salt to 1,2,4-triazole significantly affected the adsorption performance. For Examples 1 and 8-9, which used the same metal salt, copper chloride, the adsorption performance improved when the mass ratio of copper chloride to 1,2,4-triazole increased from 0.5:1.5 to 1:1.5. However, the adsorption performance decreased when the mass ratio was further increased to 2:1.5. Examples 2, 10-11, which used the same metal salt, zinc chloride, showed the same trend in adsorption performance. Examples 3, 12-13, which used the same metal salt, nickel chloride, also showed the same trend in adsorption performance. This indicates that appropriately increasing the mass ratio of the metal salt to 1,2,4-triazole helps improve the adsorption performance of ethylene, but an excessively high ratio may lead to a decrease in adsorption performance.

[0040] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit the scope of protection of the present invention. Those skilled in the art can modify or make equivalent substitutions to the technical solutions of the present invention based on the concept of the present invention, without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. An adsorbent for removing trace amounts of ethane impurities from ethylene, characterized in that, The adsorbent is mainly composed of metal chlorides and organic ligands; wherein the metal chloride is one or more of zinc chloride, copper chloride and nickel chloride, and the organic ligand is 1,2,4-triazole.

2. A method for preparing the adsorbent for removing trace amounts of ethane impurities from ethylene as described in claim 1, characterized in that, Includes the following steps: (1) Add metal chloride and organic ligand to water, stir to form a dispersed slurry-like solid, let stand for aging for 1-3 hours, and wash to obtain the adsorbent precursor; (2) The adsorbent precursor prepared in step (1) is mixed evenly with kaolin clay and guar powder to form a plastic slurry. The plastic slurry is dried, crushed and sieved to obtain an adsorbent for removing trace amounts of ethane impurities from ethylene.

3. The method for preparing the adsorbent for removing trace amounts of ethane impurities from ethylene according to claim 2, characterized in that, Step (1) The mass ratio of metal chloride to organic ligand is (0.5-2):(1-3).

4. The method for preparing the adsorbent for removing trace amounts of ethane impurities from ethylene according to claim 3, characterized in that, In step (2), the mass ratio of the adsorbent precursor to kaolin clay and guar gum powder is (0.6-1.8):(0.1-1.2):(0.01-0.18).

5. The method for preparing the adsorbent for removing trace amounts of ethane impurities from ethylene according to claim 3, characterized in that, Step (1) The stirring temperature is 10-30℃ and the stirring time is 20-60 min.

6. The method for preparing the adsorbent for removing trace amounts of ethane impurities from ethylene according to claim 4, characterized in that, Step (2) The drying temperature is 60-80℃ and the drying time is 2-10 h.

7. The application of the adsorbent according to claim 1 in removing trace amounts of ethane impurities from ethylene.

8. The application according to claim 7, characterized in that, Includes the following steps: Ethylene feed gas containing ethane impurities is passed into an adsorption bed containing the adsorbent described in claim 1 for adsorption, and ethylene product is obtained after adsorption is completed.

9. The application according to claim 8, characterized in that, The mass ratio of raw gas to adsorbent is (5-30):(1-3), and the gas flow rate is adjusted to 5-20 L / min.

10. The application according to claim 9, characterized in that, The inlet pressure of the raw gas is 0.2–0.5 MPa, and the temperature is 20–40℃.

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