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CN-117776852-B - Method for adsorption separation of propylene and propane

CN117776852BCN 117776852 BCN117776852 BCN 117776852BCN-117776852-B

Abstract

The invention relates to a method for separating propylene and propane by adsorption, which comprises the step of carrying out adsorption separation on propylene and propane by using a metal organic framework, wherein the metal organic framework material is formed by coordination assembly of divalent metal ions, malic acid and a pillared ligand. The metal organic framework material has stable structure and performance, has higher adsorption capacity to propylene, can realize high-efficiency thermodynamic-kinetic cooperative separation of propylene and propane, and still keeps the original effect of adsorption performance after repeated adsorption-regeneration for many times. The performance in the adsorption separation of propylene and propane is far superior to most solid adsorbents.

Inventors

  • BAO ZONGBI
  • CHEN FUQIANG
  • HUANG XINLEI
  • SUN HAORAN
  • REN QILONG
  • YANG QIWEI
  • ZHANG ZHIGUO

Assignees

  • 浙江大学衢州研究院

Dates

Publication Date
20260505
Application Date
20231122

Claims (19)

  1. 1. A method for adsorptive separation of propylene and propane comprises contacting a mixed gas containing propylene and propane with a metal organic framework material to perform adsorptive separation, Wherein the organic ligand of the metal organic framework material comprises R-malic acid and S-malic acid, the metal ion of the metal organic framework material is selected from one or more of nickel ion and cobalt ion, and the pillared ligand of the metal organic framework material is selected from one or more of 4,4' -bipyridine or 1, 2-di (4-pyridyl) ethylene, meso-alpha, beta-di (4-pyridyl) ethylene glycol.
  2. 2. The method of claim 1, wherein the molar ratio of R-malic acid to S-malic acid is from (20-80): from (80-20).
  3. 3. The method of claim 1, wherein the molar ratio of said R-malic acid to said S-malic acid is (40-60): 60-40.
  4. 4. The method of claim 1, wherein the molar ratio of R-malic acid to S-malic acid is 50:50.
  5. 5. The method of claim 1, wherein the organic ligand of the metal organic framework material is selected from racemic malic acid.
  6. 6. The method according to claim 1, wherein the metal ions of the metal organic framework material are nickel ions or cobalt ions, and/or The pillared ligand of the metal organic framework material is 4,4' -bipyridine.
  7. 7. The method according to claim 1, wherein the microporosity of the metal-organic framework material is >95%, and/or The pore size of the metal organic framework material is 4.6A-5.3A, and/or The metal organic framework material has a pore volume of 0.10-0.20cm 3 /g, and/or The specific surface area of the metal organic framework material is 250m 2 /g-600m 2 /g, and/or The shape of the metal organic framework material includes one or more of spherical, cubic, granular, or membranous.
  8. 8. The method of claim 7, wherein the microporosity of the metal organic framework material is 100%, and/or the pore size of the metal organic framework material is 4.5A-5.3A, and/or the pore volume of the metal organic framework material is 0.12-0.18cm 3 /g, and/or the specific surface area of the metal organic framework material is 250m 2 /g-500m 2 /g.
  9. 9. The method according to any one of claims 1 to 8, wherein the metal organic framework material is prepared by a method comprising the step of subjecting a metal containing malic acid, a metal inorganic salt and a pillared ligand to a hydrothermal reaction in a solvent.
  10. 10. The method according to claim 9, wherein the metal inorganic salt is selected from one or more of chloride, nitrate, acetate, carbonate, sulfate or perchlorate of a metal ion, and/or The solvent comprises an organic solvent and water, wherein the organic solvent is selected from one or more of methanol, ethanol, acetonitrile, acetone, N-dimethylformamide or N, N-dimethylacetamide.
  11. 11. The method of claim 10, wherein the organic solvent is methanol.
  12. 12. The method according to claim 9, wherein the metal inorganic salt is selected from acetate and/or the solvent comprises an organic solvent selected from one or more of methanol, ethanol, acetonitrile, acetone, N-dimethylformamide or N, N-dimethylacetamide and water.
  13. 13. The method according to claim 9, wherein the molar ratio of malic acid to metal inorganic salt, pillared ligand is (1-3): 1, and/or the volume ratio of organic solvent to water in the solvent is 1 (0.1-5).
  14. 14. The method of claim 13, wherein the molar ratio of malic acid to metal inorganic salt, pillared ligand is (1.5-2.5): 1.5-2.5.
  15. 15. The method according to claim 9, wherein the temperature of the hydrothermal reaction is 100 ℃ to 180 ℃ and/or the time of the hydrothermal reaction is 12 hours to 96 hours.
  16. 16. The method according to claim 9, wherein the temperature of the hydrothermal reaction is 140 ℃ to 170 ℃ and/or the time of the hydrothermal reaction is 48 hours to 72 hours.
  17. 17. The method of claim 9, further comprising washing and/or drying the product of the hydrothermal reaction.
  18. 18. The method of claim 17, wherein the washing comprises washing with water and ethanol in sequence, the drying is at a temperature of 30 ℃ to 120 ℃, and the drying is for a time of 6 hours to 24 hours.
  19. 19. The process according to any of claims 1-8, wherein the temperature of the adsorptive separation is from-5 ℃ to 50 ℃ and/or the total pressure of the mixed gas comprising propylene and propane in the adsorptive separation is from 100kPa to 5000kPa and/or the adsorptive separation is performed in a fixed bed temperature or pressure swing adsorption unit or a simulated moving bed adsorption unit.

Description

Method for adsorption separation of propylene and propane Technical Field The invention relates to the technical field of adsorption separation materials, in particular to a method for adsorbing and separating propylene and propane. Technical Field Propylene is an important chemical raw material in petrochemical industry, and is a basic raw material of three large synthetic materials (plastic, synthetic fiber and synthetic rubber). Propylene consumption and demand have increased year by year in recent years worldwide. However, in propylene production, with a large amount of propane impurities, removal of propane impurities from propylene is a key step in obtaining high purity propylene. The boiling points of propylene and propane are only 5.3K different, and the relative volatility is only 1.14, so that the traditional rectification separation process which is relied on at present has the defects of large theoretical plate number and high energy consumption. The adsorption separation technology has low requirements on equipment, does not involve phase change, realizes gas separation by contacting the adsorbent with the mixed gas, and is more energy-saving and efficient. However, propylene and propane are very similar in structure, equivalent in size, similar in polarizability and molecular polarity, and most adsorbent materials generally exhibit low adsorption separation selectivity. Cadiau et al have discovered that a pillared metal-organic framework material NbOFFIVE-1-Ni allows for molecular sieve separation of propylene propane (Science, 2016,353 (6295):137.). Although their separation selectivity is high, their slow diffusion rate limits their practical application potential. Chinese patent No. 111747818A discloses a modified molecular sieve modified by imidazole compounds to realize the adsorption separation of propylene and propane, however, the material can be obtained by ion exchange and then post modification, the preparation process is complex, the selectivity to propylene and propane is low, and the adsorption capacity to propylene is low. The adsorption amounts of Cu-BTC on propylene and propane were 7.7mmol/g and 7.1mmol/g, respectively, the adsorption capacity ratio was only 1.08, and the separation selectivity was poor (micropor. Mesopor. Mat.,. 2008,151,585.). The imidazole metal organic framework material ZIF-8 is applied to the propylene propane adsorption separation process (J.Am.chem.Soc., 2009,131,10368-10369) by using the material, and the dynamic separation selectivity of the material on propylene propane exceeds 100, but the adsorption quantity of the material on propylene propane is almost equal, the thermodynamic selectivity is poor, and the separation efficiency is limited. Therefore, the development of the adsorbent material which has thermodynamic and kinetic separation selectivity on propylene propane and is more stable has more industrial application prospect. Disclosure of Invention In order to overcome the defects in the art, the invention provides a method for separating propylene and propane by adsorption, which simultaneously adopts R-malic acid (also called D-malic acid) and S-malic acid (also called L-malic acid), particularly adopts a metal organic framework material based on racemized malic acid, and realizes the efficient thermodynamic-kinetic cooperative separation of propylene and propane. Specifically, the invention provides a method for absorbing and separating propylene and propane, which comprises the steps of contacting a mixed gas containing propylene and propane with a metal organic framework material for absorbing and separating, wherein the organic ligand of the metal organic framework material comprises R-malic acid and S-malic acid. In some embodiments, the molar ratio of the R-malic acid to the S-malic acid is from (20-80): from (80-20), preferably from (40-60): from (60-40), more preferably 50:50. In some embodiments, the molar ratio of the R-malic acid to the S-malic acid is 20:80, 30:70, 40:60, 55:45, 50:50, 45:55, 60:40, 70:30, 80:20, or any value in between. In some embodiments, the organic ligand of the metal organic framework material is selected from racemic malic acid (also known as RS-malic acid or DL-malic acid). In some embodiments, the metal ion of the metal organic framework material is selected from divalent metal ions, preferably from one or more of nickel ions and cobalt ions. In some embodiments, the pillared ligands of the metal-organic framework material are selected from one or more of 4, 4-bipyridine, 1, 2-bis (4-pyridinyl) ethylene, or meso- α, β -bis (4-pyridinyl) ethylene glycol, preferably from 4,4' -bipyridine. In the invention, the metal organic framework material is formed by coordination and assembly of divalent metal ions, malic acid and a pillared ligand, wherein the malic acid comprises R-malic acid and S-malic acid. In some embodiments, the metal organic framework material has a microporosity of >95%, more preferably 1