Preparation method of low-temperature high-efficiency hexane removal olefin adsorbent

Abstract

The present application relates to the technical field of organic chemical industry, and particularly relates to a preparation method of a low-temperature and high-efficiency adsorbent for removing olefins from hexane. The method comprises the following steps: 1. hydrogen type molecular sieve preparation: sodium type molecular sieve is exchanged by exchange liquid, washed by desalted water, repeated three times of exchange-washing, dried and calcined to obtain hydrogen type molecular sieve; 2. forming: hydrogen type molecular sieve, pseudo-boehmite and nitric acid aqueous solution are mixed according to a proportion, and a strip-shaped molecular sieve is prepared by kneading, rolling, extruding, drying and calcining; 3. modification: the strip-shaped molecular sieve is exchanged by exchange liquid, washed by desalted water, dried and calcined to prepare a molecular sieve adsorbent. The present application realizes removal of C6-C9 olefins in the recycled hexane for producing ethylene-propylene rubber, reduces the bromine value of the hexane, realizes continuous hexane refining, and improves the quality of the ethylene-propylene rubber product.

Description

Technical fields:

[0001] This invention relates to the field of organic chemical technology, and in particular to a method for preparing a low-temperature, high-efficiency hexane-to-olefin adsorbent. Background technology:

[0002] The ethylene propylene rubber (EPR) production method employs solvent polymerization using n-hexane as the solvent, which is recyclable. The hexane from the solvent recovery unit of the EPR production plant contains trace amounts of C6-C9 olefins, increasing the bromine value of the hexane in the system from 200 mg / kg to 1000 mg / kg. When the bromine value reaches 700 mg / kg, the hexane containing a high concentration of CPD (cyclopentadiene) in the solvent recovery unit is discharged to fuel oil tanks for temporary storage. Depending on the fuel oil tank level, it is periodically sent out for desorption and hydrogenation treatment before being returned. The annual outflow volume is approximately 1000 tons, with a processing cost of 3,000-4,000 RMB / ton. As production operation time increases, the C6-C9 olefin content in the hexane increases, affecting the quality of the EPR product. This process is characterized by a long process route, complex operation, unstable hydrogen content in the system, low safety performance, and high cost.

[0003] Adsorption is a low-energy-consumption solid-gas or solid-liquid separation technology widely used in chemistry, chemical engineering, petrochemicals, fine chemicals, light industry, and other industries. Adsorbents are classified according to their chemical structure into organic adsorbents (such as activated carbon, cellulose, and macroporous resins) and inorganic adsorbents (such as silica gel, activated alumina, and molecular sieves). Bennett et al. synthesized MCM-49 molecular sieve, which has an MWW framework topology with three independent pore systems: a superpore system (0.71nm×0.71nm×1.82nm) with ten-membered rings connected between layers, an intralayer sinusoidal network pore system with an effective pore size of 0.4nm×0.54nm, and a semi-cage (0.70nm×0.71nm×0.71nm) with a depth of 0.7nm on the outer surface of the crystal. In ethylene propylene rubber production, recycled n-hexane is used. Its composition is no more than 85% n-hexane, 14-15% methylcyclopentane, and 0.2-0.3% C6-C9 olefins, with a total olefin content of 100-800 mgBr / 100g based on bromine value. The molecular diameter is 0.69 nm-0.75 nm. To allow substances such as hexane to enter the pores of the adsorbent, MCM-49 molecular sieves with pore sizes greater than 0.69 nm should be selected. MCM-49 molecular sieves have well-developed pores and a large specific surface area, providing sufficient interfaces for physical adsorption. MCM series molecular sieves can be selected based on their structure. Melonn believes that 50%-70% of the 12-membered ring pores in MCM-49 molecular sieves contain Brønsted acid centers. Under medium and low temperature conditions, the larger molecular size diffuses into the acid centers in the 12-membered ring pores. The acid centers form carbocations with the π-bonding of olefins, constituting chemisorption.

[0004] In their study, "Research on Alkane / Olefin Separation Technology Using Porous Materials," Zhao Chuang and Li Ben et al. from CNOOC Tianjin Chemical Research and Design Institute Co., Ltd. investigated the adsorption and separation performance of porous materials such as silica gel, γ-Al₂O₃, 13X molecular sieve, Y molecular sieve, and ZSM-5 molecular sieve for alkanes / olefins using simulated oil as raw material in a small fixed-bed (200mL) reactor. Silica gel showed the best alkane / olefin separation effect, achieving a maximum separation degree of 0.81 under the conditions of an adsorption temperature of 40℃, a pressure of 0.5MPa, and n-octane / methylcyclohexane as the desorbent. Compared with other types of silica gel, type B silica gel with an average pore size of 4–6 nm exhibited better mass transfer and a more readily equilibrated adsorption-desorption process. The separation effect of the adsorbent after calcination and solvent regeneration did not show a significant decrease compared to the fresh adsorbent.

[0005] In their study, "Research on the Removal of Trace Olefins from Reformate Using Molecular Sieve Catalysts," Li Keming et al. from the Tianjin Branch of China Petroleum & Chemical Corporation (Sinopec) used Hβ molecular sieve, HY molecular sieve, and HY molecular sieve treated with steam as the active catalysts for olefin removal. They investigated the effects of different molecular sieves, sieve acidity, and steam treatment time on the olefin removal performance of the catalysts. The results showed that the surface acidity of the catalyst has a significant impact on its olefin removal performance. Beta acid (B acid) is the main active center, while Lewis acid (L acid) acts as an auxiliary catalyst. Excessive density of B acid centers accelerates catalyst coking and deactivation. Steam treatment can effectively improve the surface acidity and acid strength of the molecular sieve, extending the catalyst's single-pass life by up to six times that of industrial clay. The olefin removal catalyst exhibits better coking capacity, and the carbon deposits on its surface are light coke, making them easy to regenerate.

[0006] In his paper "Industrial Application of ROC-Z1 Reforming Oil Deolefins Adsorbent in Aromatic Hydrocarbon Complex," Ma Xiaojin of the Research Institute of Urumqi Petrochemical Company, China National Petroleum Corporation, reported on the analysis and separation of benzene, cyclohexane (HA), and cyclohexene (HE), and discussed the industrial application of ROC-Z1 reforming oil deolefins adsorbent in the aromatic hydrocarbon complex of Urumqi Petrochemical Company, replacing bleaching clay. Under unchanged process conditions, the ROC-Z1 reforming oil deolefins adsorbent has a long service life, exceeding 200 days in actual operation, which is 3.5 times that of ordinary bleaching clay.

[0007] Michael B. Russ reported a process combining hydrorefining and clay refining. Stephen H. Brown et al. designed a composite production process that includes three methods: activated clay refining, molecular sieve refining, and hydrorefining. Axens' Arofining TMR selective hydrogenation process, Changling Institute's FITS hydrogenation process, and Tianjin Institute's molecular sieve refining process can all be used in conjunction with activated clay refining.

[0008] Chen Yingchao of CNPC Tianjin Branch reported that using the molecular sieve catalyst TCDTO-1 to replace bleaching clay extended the replacement cycle to approximately 20 times. A molecular sieve catalyst developed by CNOOC Tianjin Chemical Research and Design Institute for the deolefination of C6-C7 mixed aromatics has a single-pass life of 12-15 months and can be regenerated 3-4 times; another molecular sieve catalyst for the deolefination of C8 components has a single-pass life of 8-10 months when the bromine index of the feedstock is <600mgBr / 100g, and can also be regenerated 3-4 times. This shows that under the same operating conditions, the single-pass life of molecular sieves is more than 8 times that of bleaching clay, effectively mitigating the safety hazards caused by frequent replacement and disposal of waste bleaching clay; through regeneration, it can be reused repeatedly, reducing solid waste emissions by 85%-90%.

[0009] Based on the above similar literature, it can be concluded that the clay refining process is the earliest and most outdated process; utilizing the abundant pores, large specific surface area and acidity of the adsorbent is currently the most competitive process for adsorbing olefins in recycled hexane. Summary of the Invention:

[0010] The technical problem to be solved by this invention is to provide a method for preparing a low-temperature, high-efficiency hexane olefin removal adsorbent. This method removes C6-C9 olefins from recycled hexane used in ethylene propylene rubber (EPR) production, reduces the bromine value of hexane, and enables continuous hexane purification, thereby improving the quality of EPR products. This method overcomes the shortcomings of existing methods where the increase in C6-C9 olefins in recycled hexane during EPR production negatively impacts the quality of the EPR product.

[0011] The technical solution adopted in this invention is: a method for preparing a low-temperature, high-efficiency hexane-to-olefins adsorbent, the steps of which are as follows:

[0012] I. Preparation of hydrogen-form molecular sieves: Sodium-form molecular sieves were prepared by exchanging with an exchange solution, washing with desalinated water, repeating the exchange-washing process three times, drying and calcining.

[0013] II. Molding: Hydrogen-type molecular sieves, boehmite and nitric acid aqueous solution are mixed in a certain proportion, and strip molecular sieves are obtained by kneading, rolling, extruding, drying and calcining.

[0014] III. Modification: The molecular sieve adsorbent is prepared by exchanging the strip molecular sieve with the exchange solution, washing with desalinated water, drying and calcining.

[0015] Further, in step one, the preparation of hydrogen-type molecular sieves, any one of the commercially available NaY, NaMCM-49, Naβ, and NaMCM-22 molecular sieve powders is used. The powder is exchanged with an exchange solution, then washed with desalinated water. The exchange-washing process is repeated three times, followed by drying and calcination to obtain hydrogen-type molecular sieves.

[0016] Furthermore, the exchange liquid in the hydrogen-type molecular sieve preparation process in step one is any one of 1%-5% nitric acid aqueous solution, 2%-10% NH4NO3 aqueous solution and 1%-5% citric acid aqueous solution.

[0017] Furthermore, the exchange process in step one of the hydrogen-type molecular sieve preparation involves an exchange temperature of 60-80℃ and an exchange time of 4-6 hours.

[0018] Furthermore, the washing process in step one of the hydrogen-type molecular sieve preparation process is as follows: washing temperature 60-80℃, washing time 4-6h.

[0019] Furthermore, the drying and calcination processes in step one of the hydrogen-type molecular sieve preparation are as follows: drying temperature 110-120℃, drying time 4-8h; calcination temperature 450-500℃, calcination time 2-4h.

[0020] Furthermore, in the mixing process of step two, hydrogen molecular sieve, boehmite, and nitric acid aqueous solution are mixed in a certain proportion, with the mass ratio of hydrogen molecular sieve:boehmite:nitric acid aqueous solution being 100:15-25:100.

[0021] Furthermore, in the kneading and rolling process of step two, the kneading time is 2-4 hours, the rolling time is 2-4 hours, and the strip is extruded after the rolling is qualified.

[0022] Furthermore, the drying and calcination in the second molding process are as follows: drying temperature 110-120℃, drying time 4-8h; calcination temperature 500-540℃, calcination time 4-8h.

[0023] Furthermore, the exchange in the modification process of step three is any one of the following: 1%-5% nitric acid aqueous solution, 2%-10% NH4NO3 aqueous solution, and 1%-5% citric acid aqueous solution.

[0024] Furthermore, the exchange and washing processes in step three of the modification process are as follows: exchange temperature 60-80℃, exchange time 4-6h; washing temperature 60-80℃, washing time 4-6h.

[0025] Furthermore, the drying and calcination in the modification process in step three are as follows: drying temperature 110-120℃, drying time 4-8h; calcination temperature 450-500℃, calcination time 2-4h.

[0026] Furthermore, in the application of the molecular sieve adsorbent obtained in step three, the olefins are removed from the recycled hexane used in the production of ethylene propylene rubber, with an adsorption temperature of 20℃~70℃ and an adsorption pressure of 0.1MPa~0.7MPa.

[0027] The beneficial effects of this invention are:

[0028] (1) The molecular sieve adsorbent prepared by the present invention has a large specific surface area and a large effective pore volume.

[0029] (2) The molecular sieve adsorbent prepared in this invention has a low adsorption temperature and a large adsorption capacity in the cyclic hexane removal of olefins during the production of ethylene propylene rubber. Detailed implementation method:

[0030] Example 1

[0031] Weigh 100g of NaY molecular sieve raw powder, add 2% nitric acid aqueous solution, and exchange at 60℃ for 4h. Remove the exchange solution. Wash with demineralized water at 60℃ for 2h. Repeat the exchange-washing process 3 times. Take out the molecular sieve and dry at 110℃ for 8h; after drying, calcine at 450℃ for 2h to prepare HY molecular sieve raw powder. Weigh 100g of HY molecular sieve and 15g of boehmite, add 1% nitric acid aqueous solution in batches, knead, then roll for 2h, and extrude using an extruder; then dry at 120℃ for 4h; calcine at 500℃ for 4h. After cooling, modify by adding 1% nitric acid aqueous solution and exchanging at 60℃ for 4h; wash with demineralized water at 60℃ for 2h. The strip-shaped molecular sieve was removed and dried at 110℃ for 8 hours. After drying, it was calcined at 450℃ for 2 hours to prepare the HY molecular sieve adsorbent. The specific surface area was measured to be 596 m². 2 / g, effective pore volume 0.45ml / g.

[0032] Molecular sieve adsorbents prepared in Example 1 were used for the adsorption of recycled hexane in the production of ethylene propylene rubber, resulting in the removal of olefins. The adsorption conditions were: a bromine value of 210 mgBr / 100 g for the recycled hexane, an adsorption temperature of 30 °C, and a space velocity of 0.5 h⁻¹. -1 Under an adsorption pressure of 0.1 MPa, the adsorption capacity of olefins was determined to be 685 g / kg.

[0033] Example 2

[0034] Weigh 100g of NaY molecular sieve raw powder, add 3% nitric acid aqueous solution, and exchange for 6 hours at 60℃. Remove the exchange solution. Wash with demineralized water at 70℃ for 4 hours. Repeat the exchange-washing process 3 times. Take out the molecular sieve and dry it at 120℃ for 8 hours; after drying, calcine it at 470℃ for 3 hours to prepare HY molecular sieve raw powder. Weigh 100g of HY molecular sieve and 20g of boehmite, add 1% nitric acid aqueous solution in batches, knead, and then roll for 3 hours. Extrude the mixture using an extruder; then dry at 120℃ for 6 hours; calcine at 520℃ for 4 hours. After cooling, modify the mixture by adding 1% nitric acid aqueous solution and exchanging for 6 hours at 60℃; wash with demineralized water at 60℃ for 3 hours. The strip-shaped molecular sieve was removed and dried at 120℃ for 8 hours; after drying, it was calcined at 470℃ for 2 hours to prepare HY molecular sieve adsorbent. The specific surface area was measured to be 612 m². 2 / g, effective pore volume 0.44ml / g.

[0035] Molecular sieve adsorbents prepared in Example 2 were used for the adsorption of recycled hexane in the production of ethylene propylene rubber, resulting in the removal of olefins. The adsorption conditions were: a bromine value of 210 mgBr / 100 g for the recycled hexane, an adsorption temperature of 30 °C, and a space velocity of 0.5 h⁻¹. -1 Under an adsorption pressure of 0.1 MPa, the adsorption capacity of olefins was determined to be 689 g / kg.

[0036] Example 3

[0037] Weigh 100g of NaY molecular sieve raw powder, add 3% nitric acid aqueous solution, and exchange at 70℃ for 4h. Remove the exchange solution. Wash with demineralized water at 80℃ for 6h. Repeat the exchange-washing process 3 times. Take out the molecular sieve and dry at 120℃ for 8h; after drying, calcine at 500℃ for 3h to prepare HY molecular sieve raw powder. Weigh 100g of HY molecular sieve and 18g of boehmite, add 1% nitric acid aqueous solution in batches, knead, then roll for 4h, and extrude using an extruder; then dry at 120℃ for 4h; calcine at 540℃ for 4h. After cooling, modify by adding 5% nitric acid aqueous solution and exchanging at 80℃ for 2h; wash with demineralized water at 60℃ for 4h. The strip-shaped molecular sieve was removed and dried at 120℃ for 4 hours. After drying, it was calcined at 500℃ for 4 hours to prepare the HY molecular sieve adsorbent. The specific surface area was measured to be 626 m². 2 / g, effective pore volume 0.45ml / g.

[0038] Molecular sieve adsorbents prepared in Example 3 were used for the adsorption of recycled hexane in the production of ethylene propylene rubber, resulting in the removal of olefins. The adsorption conditions were: a bromine value of 210 mgBr / 100 g for the recycled hexane, an adsorption temperature of 30 °C, and a space velocity of 0.5 h⁻¹. -1 Under an adsorption pressure of 0.1 MPa, the adsorption capacity of olefins was determined to be 672 / kg.

[0039] Example 4

[0040] Weigh 100g of NaY molecular sieve raw powder, add 5% ammonium nitrate aqueous solution, and exchange for 6 hours at 60℃. Remove the exchange solution. Wash with demineralized water at 80℃ for 4 hours. Repeat the exchange-washing process 3 times. Take out the molecular sieve, dry it at 120℃ for 6 hours, and then calcine it at 470℃ for 3 hours to prepare HY molecular sieve raw powder. Weigh 100g of HY molecular sieve and 20g of boehmite, add 1% nitric acid solution in batches, knead, and then roll for 3 hours. Extrude the mixture using an extruder; then dry it at 120℃ for 6 hours; calcine it at 520℃ for 4 hours. After cooling, modify it by adding 3% ammonium nitrate aqueous solution and exchanging for 6 hours at 60℃; then wash it with demineralized water at 60℃ for 3 hours. The strip-shaped molecular sieve was removed and dried at 120℃ for 6 hours. After drying, it was calcined at 470℃ for 2 hours to prepare the HY molecular sieve adsorbent. The specific surface area was measured to be 596 m². 2 / g, effective pore volume 0.44ml / g.

[0041] Molecular sieve adsorbents prepared in Example 4 were used for the adsorption of recycled hexane in the production of ethylene propylene rubber, resulting in the removal of olefins. The adsorption conditions were: a bromine value of 210 mgBr / 100 g for the recycled hexane, an adsorption temperature of 40 °C, and a space velocity of 0.5 h⁻¹. -1 Under an adsorption pressure of 0.6 MPa, the adsorption capacity of olefins was determined to be 688 g / kg.

[0042] Example 5

[0043] Weigh 100g of NaY molecular sieve raw powder, add 5% citric acid aqueous solution, and exchange at 80℃ for 6h. Remove the exchange solution. Wash with demineralized water at 80℃ for 4h. Repeat the exchange-washing process 3 times. Take out the molecular sieve, dry at 120℃ for 4h, and then calcine at 470℃ for 3h to prepare HY molecular sieve raw powder. Weigh 100g of HY molecular sieve and 20g of boehmite, add 1% nitric acid solution in batches, knead, and then roll for 3h. Extrude using an extruder; then dry at 120℃ for 6h; calcine at 540℃ for 4h. After cooling, modify by adding 5% citric acid aqueous solution and exchanging at 60℃ for 6h; wash with demineralized water at 60℃ for 3h. The strip-shaped molecular sieve was removed and dried at 120℃ for 6 hours. After drying, it was calcined at 500℃ for 2 hours to prepare the HY molecular sieve adsorbent. The specific surface area was measured to be 576 m². 2 / g, effective pore volume 0.44ml / g.

[0044] Molecular sieve adsorbents prepared in Example 5 were used for the adsorption of recycled hexane in the production of ethylene propylene rubber, resulting in the removal of olefins. The optimal conditions were: a bromine value of 210 mgBr / 100 g for the recycled hexane, an adsorption temperature of 70 °C, and a space velocity of 0.5 h⁻¹. -1 Under an adsorption pressure of 0.6 MPa, the adsorption capacity of olefins was determined to be 679 g / kg.

[0045] Example 6

[0046] Weigh 100g of NaMCM-49 molecular sieve raw powder, add 1% nitric acid aqueous solution, and exchange at 60℃ for 4h. Remove the exchange solution. Wash with demineralized water at 60℃ for 2h. Repeat the exchange-washing process 3 times. Take out the molecular sieve, dry at 110℃ for 8h, and then calcine at 450℃ for 2h to prepare HMCM-49 molecular sieve raw powder. Weigh 100g of HY molecular sieve and 15g of boehmite, add 1% nitric acid aqueous solution in batches, knead, and then roll for 2h. Extrude using an extruder; then dry at 120℃ for 4h; calcine at 500℃ for 4h; after cooling, modify by adding 1% nitric acid aqueous solution and exchanging at 60℃ for 4h; wash with demineralized water at 60℃ for 2h. The strip-shaped molecular sieve was removed and dried at 110℃ for 8 hours; after drying, it was calcined at 450℃ for 2 hours to prepare HMCM-49 molecular sieve adsorbent. The specific surface area was measured to be 5996 m². 2 / g, effective pore volume 0.45ml / g.

[0047] Molecular sieve adsorbents prepared in Example 1 were used for the adsorption of recycled hexane in the production of ethylene propylene rubber, resulting in the removal of olefins. The adsorption conditions were: a bromine value of 210 mgBr / 100 g for the recycled hexane, an adsorption temperature of 30 °C, and a space velocity of 0.5 h⁻¹. -1 Under an adsorption pressure of 0.3 MPa, the adsorption capacity of olefins was determined to be 698 g / kg.

[0048] Example 7

[0049] Weigh 100g of NaMCM-49 molecular sieve raw powder, add 3% nitric acid aqueous solution, and exchange at 60℃ for 6h. Remove the exchange solution. Wash with demineralized water at 70℃ for 4h. Repeat the exchange-washing process 3 times. Take out the molecular sieve, dry at 120℃, and then calcine at 470℃ for 3h to prepare HMCM-49 molecular sieve raw powder. Weigh 100g of HY molecular sieve and 20g of boehmite, add 1% nitric acid aqueous solution in batches, knead, and then roll for 3h. Extrude using an extruder; then dry at 120℃ for 6h; calcine at 520℃ for 4h. After cooling, modify by adding 1% nitric acid aqueous solution and exchanging at 60℃ for 6h; wash with demineralized water at 60℃ for 3h. The strip-shaped molecular sieve was removed and dried at 120℃, followed by calcination at 470℃ for 2 hours to prepare HMCM-49 molecular sieve adsorbent. The specific surface area was measured to be 612 m². 2 / g, effective pore volume 0.44ml / g.

[0050] Molecular sieve adsorbents prepared in Example 2 were used for the adsorption of recycled hexane in the production of ethylene propylene rubber, resulting in the removal of olefins. The adsorption conditions were: a bromine value of 210 mgBr / 100 g for the recycled hexane, an adsorption temperature of 60 °C, and a space velocity of 0.5 h⁻¹. -1 Under an adsorption pressure of 0.5 MPa, the adsorption capacity of olefins was determined to be 683 g / kg.

[0051] Example 8

[0052] Weigh 100g of NaMCM-49 molecular sieve powder and add 3% nitric acid aqueous solution. Exchange the solution at 70℃ for 4 hours. Remove the exchange solution. Wash with deionized water at 80℃ for 6 hours. Repeat the exchange-washing process three times. Remove the molecular sieve and dry it at 120℃ for 4 hours. After drying, calcine it at 500℃ for 3 hours to prepare HMCM-49 molecular sieve powder. 100g of HMCM-49 molecular sieve and 18g of boehmite were weighed and added in batches with 1% nitric acid solution. The mixture was kneaded and then rolled for 4 hours, followed by extrusion using an extruder. The mixture was then dried at 120℃ for 4 hours, and calcined at 540℃ for 4 hours. After cooling, modification was performed by adding 5% nitric acid solution and exchanging the solution at 80℃ for 2 hours. The mixture was then washed with demineralized water at 60℃ for 4 hours. The strip-shaped molecular sieve was removed and dried at 120℃ for 5 hours. After drying, it was calcined at 500℃ for 4 hours to prepare the HMCM-49 molecular sieve adsorbent. The specific surface area was measured to be 591 m². 2 / g, effective pore volume 0.44ml / g.

[0053] Molecular sieve adsorbents were prepared using Example 3 and used for the adsorption of recycled hexane in the production of ethylene propylene rubber, thereby removing olefins. The optimal conditions were: a bromine value of 210 mgBr / 100 g for the recycled hexane, an adsorption temperature of 60 °C, and a space velocity of 0.5 h⁻¹. -1 Under an adsorption pressure of 0.6 MPa, the adsorption capacity of olefins was determined to be 689 g / kg.

[0054] Example 9

[0055] Weigh 100g of NaMCM-49 molecular sieve powder and add 5% ammonium nitrate aqueous solution. Exchange the solution at 60℃ for 6 hours. Remove the exchange solution. Wash with deionized water at 80℃ for 4 hours. Repeat the exchange-washing process three times. Remove the molecular sieve and dry it at 120℃ for 6 hours. After drying, calcine it at 470℃ for 3 hours to prepare HMCM-49 molecular sieve powder. 100g of HMCM-49 molecular sieve and 20g of boehmite were weighed and added in batches with 1% nitric acid solution. The mixture was kneaded and then rolled for 3 hours, followed by extrusion using an extruder. The mixture was then dried at 120℃ for 6 hours, and calcined at 520℃ for 4 hours. After cooling, modification was performed by adding 3% ammonium nitrate solution and exchanging the solution at 60℃ for 6 hours. The mixture was then washed with demineralized water at 60℃ for 3 hours. The strip-shaped molecular sieve was removed and dried at 120℃ for 4 hours. After drying, it was calcined at 470℃ for 2 hours to prepare the HMCM-49 molecular sieve adsorbent. The specific surface area was determined to be 613 m². 2 / g, effective pore volume 0.44ml / g.

[0056] Molecular sieve adsorbents prepared in Example 9 were used for the adsorption of recycled hexane in the production of ethylene propylene rubber, resulting in the removal of olefins. The adsorption conditions were: a bromine value of 210 mgBr / 100 g for the recycled hexane, an adsorption temperature of 30 °C, and a space velocity of 0.5 h⁻¹. -1 Under an adsorption pressure of 0.2 MPa, the adsorption capacity of olefins was determined to be 691 g / kg.

[0057] Example 10

[0058] Weigh 100g of NaMCM-49 molecular sieve powder and add 5% citric acid aqueous solution. Exchange the solution at 60℃ for 6 hours. Remove the exchange solution. Wash with deionized water at 80℃ for 4 hours. Repeat the exchange-washing process three times. Remove the molecular sieve and dry it at 120℃ for 4 hours. After drying, calcine it at 470℃ for 3 hours to prepare HMCM-49 molecular sieve powder. 100g of HMCM-49 molecular sieve and 20g of boehmite were weighed and added in batches with 1% nitric acid solution. The mixture was kneaded and then rolled for 3 hours, followed by extrusion into strips. The strips were then dried at 120℃ for 6 hours, and calcined at 540℃ for 4 hours. After cooling, the mixture was modified by adding 5% citric acid solution and exchanging the solution at 60℃ for 6 hours. The strips were then washed with demineralized water at 60℃ for 3 hours. The strip-shaped molecular sieve was removed and dried at 120℃ for 4 hours. After drying, it was calcined at 500℃ for 2 hours to prepare the HMCM-49 molecular sieve adsorbent. The specific surface area was determined to be 576 m². 2 / g, effective pore volume 0.44ml / g.

[0059] Molecular sieve adsorbents prepared in Example 10 were used for the adsorption of recycled hexane in the production of ethylene propylene rubber, resulting in the removal of olefins. The optimal conditions were: a bromine value of 210 mgBr / 100 g for the recycled hexane, an adsorption temperature of 70 °C, and a space velocity of 0.5 h⁻¹. -1 Under an adsorption pressure of 0.6 MPa, the adsorption capacity of olefins was determined to be 679 g / kg.

[0060] Example 11

[0061] Weigh 100g of Naβ molecular sieve raw powder, add 1% nitric acid aqueous solution, and exchange at 60℃ for 4h. Remove the exchange solution. Wash with demineralized water at 60℃ for 2h. Repeat the exchange-washing process 3 times. Take out the molecular sieve and dry at 110℃ for 8h; after drying, calcine at 450℃ for 2h to prepare Hβ molecular sieve raw powder. Weigh 100g of Hβ molecular sieve and 15g of boehmite, add 1% nitric acid aqueous solution in batches, knead, then roll for 2h, and extrude using an extruder; then dry at 120℃ for 4h; calcine at 500℃ for 4h. After cooling, modify by adding 1% nitric acid aqueous solution and exchanging at 60℃ for 4h; wash with demineralized water at 60℃ for 2h. The strip-shaped molecular sieve was removed and dried at 110℃ for 8 hours; after drying, it was calcined at 450℃ for 2 hours to prepare the Hβ molecular sieve adsorbent. The specific surface area was measured to be 597 m². 2 / g, effective pore volume 0.45ml / g.

[0062] The molecular sieve adsorbent prepared in Example 11 was used for the adsorption of recycled hexane in the production of ethylene propylene rubber, thereby removing olefins. The optimal conditions were: a bromine value of 210 mgBr / 100 g for the recycled hexane, an adsorption temperature of 40 °C, and a space velocity of 0.5 h⁻¹. -1 Under an adsorption pressure of 0.3 MPa, the adsorption capacity of olefins was determined to be 687 g / kg.

[0063] Example 12

[0064] Weigh 100g of Naβ9 molecular sieve raw powder, add 3% nitric acid aqueous solution, and exchange for 6 hours at 60℃. Remove the exchange solution. Wash with demineralized water at 70℃ for 4 hours. Repeat the exchange-washing process 3 times. Take out the molecular sieve and dry it at 120℃ for 4 hours; after drying, calcine it at 470℃ for 3 hours to prepare Hβ molecular sieve raw powder. Weigh 100g of Hβ molecular sieve and 20g of boehmite, add 1% nitric acid aqueous solution in batches, knead, and then roll for 3 hours. Extrude the mixture using an extruder; then dry at 120℃ for 6 hours; calcine at 520℃ for 4 hours. After cooling, modify the mixture by adding 1% nitric acid aqueous solution and exchanging for 6 hours at 60℃; wash with demineralized water at 60℃ for 3 hours. The strip-shaped molecular sieve was removed and dried at 120℃ for 4 hours; after drying, it was calcined at 470℃ for 2 hours to prepare the Hβ molecular sieve adsorbent. The specific surface area was measured to be 602 m². 2 / g, effective pore volume 0.44ml / g.

[0065] Molecular sieve adsorbents prepared in Example 12 were used for the adsorption of recycled hexane in the production of ethylene propylene rubber, resulting in the removal of olefins. The conditions were: recycled hexane with a bromine value of 210 mgBr / 100g, adsorption temperature of 60°C, and space velocity of 0.5 h⁻¹. -1 Under an adsorption pressure of 0.5 MPa, the adsorption capacity of olefins was determined to be 689 g / kg.

[0066] Example 13

[0067] Weigh 100g of Naβ molecular sieve raw powder, add 3% nitric acid aqueous solution, and exchange at 70℃ for 4h. Remove the exchange solution. Wash with demineralized water at 80℃ for 6h. Repeat the exchange-washing process 3 times. Take out the molecular sieve and dry at 120℃ for 4h; after drying, calcine at 500℃ for 3h to prepare Hβ molecular sieve raw powder. Weigh 100g of Hβ molecular sieve and 18g of boehmite, add 1% nitric acid aqueous solution in batches, knead, then roll for 4h, and extrude using an extruder; then dry at 120℃ for 4h; calcine at 540℃ for 4h. After cooling, modify by adding 5% nitric acid aqueous solution and exchanging at 80℃ for 2h; wash with demineralized water at 60℃ for 4h. The strip-shaped molecular sieve was removed and dried at 120℃ for 4 hours. After drying, it was calcined at 500℃ for 4 hours to prepare the Hβ molecular sieve adsorbent. The specific surface area was measured to be 587 m². 2 / g, effective pore volume 0.45ml / g.

[0068] Molecular sieve adsorbents prepared in Example 13 were used for the adsorption of recycled hexane in the production of ethylene propylene rubber, resulting in the removal of olefins. The adsorption conditions were: a bromine value of 210 mgBr / 100 g for the recycled hexane, an adsorption temperature of 30 °C, and a space velocity of 0.5 h⁻¹. -1 Under an adsorption pressure of 0.4 MPa, the adsorption capacity of olefins was determined to be 686 / kg.

[0069] Example 14

[0070] Weigh 100g of Naβ molecular sieve raw powder, add 5% ammonium nitrate aqueous solution, and exchange for 6 hours at 60℃. Remove the exchange solution. Wash with demineralized water at 80℃ for 4 hours. Repeat the exchange-washing process 3 times. Take out the molecular sieve and dry it at 120℃ for 4 hours; after drying, calcine it at 470℃ for 3 hours to prepare Hβ molecular sieve raw powder. Weigh 100g of Hβ molecular sieve and 20g of boehmite, add 1% nitric acid aqueous solution in batches, knead, and then roll for 3 hours. Extrude the mixture using an extruder; then dry at 120℃ for 6 hours; calcine at 520℃ for 4 hours. After cooling, modify the mixture by adding 10% ammonium nitrate aqueous solution and exchanging for 6 hours at 60℃; wash with demineralized water at 60℃ for 3 hours. The strip-shaped molecular sieve was removed and dried at 120℃. After drying, it was calcined at 470℃ for 2 hours to prepare the Hβ molecular sieve adsorbent. The specific surface area was measured to be 618 m². 2 / g, effective pore volume 0.44ml / g.

[0071] Molecular sieve adsorbents prepared in Example 14 were used for the adsorption of recycled hexane in the production of ethylene propylene rubber, resulting in the removal of olefins. The adsorption conditions were: a bromine value of 210 mgBr / 100 g for the recycled hexane, an adsorption temperature of 30 °C, and a space velocity of 0.5 h⁻¹. -1 Under an adsorption pressure of 0.7 MPa, the adsorption capacity of olefins was determined to be 683 g / kg.

[0072] Example 15

[0073] Weigh 100g of Naβ molecular sieve raw powder, add 1% citric acid aqueous solution, and exchange for 6 hours at 60℃. Remove the exchange solution. Wash with demineralized water at 80℃ for 4 hours. Repeat the exchange-washing process 3 times. Take out the molecular sieve and dry it at 120℃ for 4 hours; after drying, calcine it at 470℃ for 3 hours to prepare Hβ molecular sieve raw powder. Weigh 100g of Hβ molecular sieve and 20g of boehmite, add 1% nitric acid aqueous solution in batches, knead, and then roll for 3 hours. Extrude the mixture using an extruder; then dry at 120℃ for 6 hours; calcine at 540℃ for 4 hours. After cooling, modify the mixture by adding 1% citric acid aqueous solution and exchanging for 6 hours at 60℃; wash with demineralized water at 60℃ for 3 hours. The strip-shaped molecular sieve was removed and dried at 120℃ for 4 hours; after drying, it was calcined at 540℃ for 2 hours to prepare the Hβ molecular sieve adsorbent. The specific surface area was measured to be 578 m². 2 / g, effective pore volume 0.45ml / g.

[0074] Molecular sieve adsorbents prepared in Example 15 were used for the adsorption of recycled hexane in the production of ethylene propylene rubber, resulting in the removal of olefins. The adsorption conditions were: a bromine value of 210 mgBr / 100 g for the recycled hexane, an adsorption temperature of 50 °C, and a space velocity of 0.5 h⁻¹. -1 Under an adsorption pressure of 0.7 MPa, the adsorption capacity of olefins was determined to be 685 g / kg.

[0075] Example 16

[0076] Weigh 100g of NaMCM-22 molecular sieve powder and add 1% nitric acid aqueous solution. Exchange the solution at 60℃ for 4 hours. Remove the exchange solution. Wash with deionized water at 60℃ for 2 hours. Repeat the exchange-washing process three times. Remove the molecular sieve and dry it at 110℃ for 8 hours. After drying, calcine it at 450℃ for 2 hours to prepare HMCM-22 molecular sieve powder. 100g of HMCM-22 molecular sieve and 15g of pseudoboehmite were weighed and added in batches with 1% nitric acid solution. The mixture was kneaded and then rolled for 2 hours, followed by extrusion using an extruder. The mixture was then dried at 120℃ for 4 hours, and calcined at 450℃ for 4 hours. After cooling, modification was performed by adding 1% nitric acid solution and exchanging the mixture at 60℃ for 4 hours. The mixture was then washed with demineralized water at 60℃ for 2 hours. The strip-shaped molecular sieve was removed and dried at 110℃ for 8 hours. After drying, it was calcined at 500℃ for 2 hours to prepare the Hβ molecular sieve adsorbent. The specific surface area was determined to be 596 m². 2 / g, effective pore volume 0.45ml / g.

[0077] Molecular sieve adsorbents prepared in Example 16 were used for the adsorption of recycled hexane in the production of ethylene propylene rubber, resulting in the removal of olefins. The optimal conditions were: a bromine value of 210 mgBr / 100 g for the recycled hexane, an adsorption temperature of 40 °C, and a space velocity of 0.5 h⁻¹. -1 Under an adsorption pressure of 0.4 MPa, the adsorption capacity of olefins was determined to be 683 g / kg.

[0078] Example 17

[0079] Weigh 100g of NaMCM-22 molecular sieve powder and add 3% nitric acid aqueous solution. Exchange the solution at 60℃ for 6 hours. Remove the exchange solution. Wash with deionized water at 70℃ for 4 hours. Repeat the exchange-washing process three times. Remove the molecular sieve and dry it at 120℃ for 4 hours. After drying, calcine it at 470℃ for 3 hours to prepare HMCM-22 molecular sieve powder. 100g of HMCM-22 molecular sieve and 20g of boehmite were weighed and added in batches with 1% nitric acid solution. The mixture was kneaded and then rolled for 3 hours, followed by extrusion using an extruder. The mixture was then dried at 120℃ for 6 hours, and calcined at 520℃ for 4 hours. After cooling, modification was performed by adding 1% nitric acid solution and exchanging the mixture at 60℃ for 6 hours. The mixture was then washed with demineralized water at 60℃ for 3 hours. The strip-shaped molecular sieve was removed and dried at 120℃ for 4 hours. After drying, it was calcined at 470℃ for 2 hours to prepare the HMCM-22 molecular sieve adsorbent. The specific surface area was measured to be 602 m².2 / g, effective pore volume 0.44ml / g.

[0080] The molecular sieve adsorbent prepared in Example 17 was used for the adsorption of recycled hexane in the production of ethylene propylene rubber, thereby removing olefins. The optimal conditions were: a bromine value of 210 mgBr / 100 g for the recycled hexane, an adsorption temperature of 40 °C, and a space velocity of 0.5 h⁻¹. -1 Under an adsorption pressure of 0.7 MPa, the adsorption capacity of olefins was determined to be 691 g / kg.

[0081] Example 18

[0082] Weigh 100g of NaMCM-22 molecular sieve powder and add 3% nitric acid aqueous solution. Exchange the solution at 70℃ for 4 hours. Remove the exchange solution. Wash with deionized water at 80℃ for 6 hours. Repeat the exchange-washing process three times. Remove the molecular sieve and dry it at 120℃ for 4 hours. After drying, calcine it at 500℃ for 3 hours to prepare HMCM-22 molecular sieve powder. 100g of HMCM-22 molecular sieve and 18g of boehmite were weighed and added in batches with 1% nitric acid solution. The mixture was kneaded, then rolled for 4 hours, and extruded into strips using an extruder. The strips were then dried at 120℃ for 4 hours, followed by calcination at 540℃ for 4 hours. After cooling, modification was performed by adding 5% nitric acid solution and exchanging the solution at 80℃ for 2 hours. The strips were then washed with demineralized water at 60℃ for 4 hours. The strip-shaped molecular sieve was removed and dried at 120℃ for 4 hours. After drying, it was calcined at 500℃ for 4 hours to prepare the HMCM-22 molecular sieve adsorbent. The specific surface area was determined to be 588 m². 2 / g, effective pore volume 0.45ml / g.

[0083] The molecular sieve adsorbent prepared in Example 18 was used for the adsorption of recycled hexane in the production of ethylene propylene rubber, thereby removing olefins. The optimal conditions were: a bromine value of 210 mgBr / 100 g for the recycled hexane, an adsorption temperature of 50 °C, and a space velocity of 0.5 h⁻¹. -1 Under an adsorption pressure of 0.6 MPa, the adsorption capacity of olefins was determined to be 687 / kg.

[0084] Example 19

[0085] Weigh 100g of NaMCM-22 molecular sieve powder and add 5% ammonium nitrate aqueous solution. Exchange the solution at 60℃ for 6 hours. Remove the exchange solution. Wash with deionized water at 80℃ for 4 hours. Repeat the exchange-washing process three times. Remove the molecular sieve and dry it at 120℃ for 4 hours. After drying, calcine it at 470℃ for 3 hours to prepare HMCM-22 molecular sieve powder. 100g of HMCM-22 molecular sieve and 20g of boehmite were weighed and added in batches with 1% nitric acid solution. The mixture was kneaded and then rolled for 3 hours, followed by extrusion using an extruder. The mixture was then dried at 120℃ for 6 hours, and calcined at 520℃ for 4 hours. After cooling, modification was performed by adding 3% ammonium nitrate solution and exchanging the mixture at 60℃ for 6 hours. The mixture was then washed with demineralized water at 60℃ for 3 hours. The strip-shaped molecular sieve was removed and dried at 120℃ for 4 hours. After drying, it was calcined at 470℃ for 2 hours to prepare the HMCM-22 molecular sieve adsorbent. The specific surface area was measured to be 609 m². 2 / g, effective pore volume 0.45ml / g.

[0086] The molecular sieve adsorbent prepared in Example 19 was used for the adsorption of recycled hexane in the production of ethylene propylene rubber, thereby removing olefins. The adsorption conditions were: a bromine value of 210 mgBr / 100 g for the recycled hexane, an adsorption temperature of 30 °C, and a space velocity of 0.5 h⁻¹. -1 Under an adsorption pressure of 0.4 MPa, the adsorption capacity of olefins was determined to be 687 g / kg.

[0087] Example 20

[0088] Weigh 100g of NaMC-22 molecular sieve powder and add 5% citric acid aqueous solution. Exchange the solution at 60℃ for 6 hours. Remove the exchange solution. Wash with deionized water at 80℃ for 4 hours. Repeat the exchange-washing process three times. Remove the molecular sieve and dry it at 120℃ for 4 hours. After drying, calcine it at 470℃ for 3 hours to prepare HMCM-22 molecular sieve powder. 100g of HMCM-22 molecular sieve and 20g of boehmite were weighed and added in batches with 1% nitric acid solution. The mixture was kneaded and then rolled for 3 hours, followed by extrusion using an extruder. The mixture was then dried at 120℃ for 6 hours, and calcined at 540℃ for 4 hours. After cooling, modification was performed by adding 5% citric acid solution and exchanging the solution at 60℃ for 6 hours. The mixture was then washed with demineralized water at 60℃ for 3 hours. The strip-shaped molecular sieve was removed and dried at 120℃ for 4 hours. After drying, it was calcined at 540℃ for 2 hours to prepare the HMCM-22 molecular sieve adsorbent. The specific surface area was measured to be 571 m². 2 / g, effective pore volume 0.44ml / g.

[0089] Molecular sieve adsorbents prepared in Example 20 were used for the adsorption of recycled hexane in the production of ethylene propylene rubber, resulting in the removal of olefins. The adsorption conditions were: a bromine value of 210 mgBr / 100 g for the recycled hexane, an adsorption temperature of 40 °C, and a space velocity of 0.5 h⁻¹. -1 Under an adsorption pressure of 0.5 MPa, the adsorption capacity of olefins was determined to be 691 g / kg.

[0090] Example 21

[0091] Weigh 100g of NaY molecular sieve raw powder, add 2% ammonium nitrate aqueous solution, and exchange for 6 hours at 60℃. Remove the exchange solution. Wash with demineralized water at 80℃ for 4 hours. Repeat the exchange-washing process 3 times. Take out the molecular sieve, dry it at 120℃ for 6 hours, and then calcine it at 470℃ for 3 hours to prepare HY molecular sieve raw powder. Weigh 100g of HY molecular sieve and 20g of boehmite, add 100g of 1% nitric acid solution in batches, knead, and then roll for 3 hours. Extrude the mixture using an extruder; then dry it at 120℃ for 6 hours; calcine it at 520℃ for 4 hours. After cooling, modify it by adding 3% ammonium nitrate aqueous solution and exchanging for 6 hours at 60℃; then wash it with demineralized water at 60℃ for 3 hours. The strip-shaped molecular sieve was removed and dried at 120℃ for 6 hours. After drying, it was calcined at 470℃ for 2 hours to prepare the HY molecular sieve adsorbent. The specific surface area was measured to be 595 m². 2 / g, effective pore volume 0.45ml / g.

[0092] The molecular sieve adsorbent prepared in Example 21 was used for the adsorption of recycled hexane in the production of ethylene propylene rubber, thereby removing olefins. The optimal conditions were: a bromine value of 210 mgBr / 100 g for the recycled hexane, an adsorption temperature of 40 °C, and a space velocity of 0.5 h⁻¹. -1 Under an adsorption pressure of 0.6 MPa, the adsorption capacity of olefins was determined to be 679 g / kg.

[0093] Example 22

[0094] Weigh 100g of NaMC-22 molecular sieve powder and add 10% ammonium nitrate aqueous solution. Exchange the solution at 60℃ for 6 hours. Remove the exchange solution. Wash with deionized water at 80℃ for 4 hours. Repeat the exchange-washing process three times. Remove the molecular sieve and dry it at 120℃ for 4 hours. After drying, calcine it at 470℃ for 3 hours to prepare HMCM-22 molecular sieve powder. 100g of HMCM-22 molecular sieve and 20g of boehmite were weighed and added in batches to 100g of 1% nitric acid solution. The mixture was kneaded and then rolled for 3 hours, followed by extrusion using an extruder. The mixture was then dried at 120℃ for 6 hours, and calcined at 540℃ for 4 hours. After cooling, modification was performed by adding 5% ammonium nitrate solution and exchanging the solution at 60℃ for 6 hours. The mixture was then washed with demineralized water at 60℃ for 3 hours. The molecular sieve strips were removed and dried at 120℃ for 4 hours. After drying, they were calcined at 540℃ for 2 hours to prepare the HMCM-22 molecular sieve adsorbent. The specific surface area was measured to be 571 m². 2 / g, effective pore volume 0.45ml / g.

[0095] The molecular sieve adsorbent prepared in Example 22 was used for the adsorption of recycled hexane in the production of ethylene propylene rubber, thereby removing olefins. The optimal conditions were: a bromine value of 210 mgBr / 100 g for the recycled hexane, an adsorption temperature of 40 °C, and a space velocity of 0.5 h⁻¹. -1 Under an adsorption pressure of 0.7 MPa, the adsorption capacity of olefins was determined to be 689 g / kg.

[0096] Example 23

[0097] Weigh 100g of Naβ molecular sieve raw powder, add 3% citric acid aqueous solution, and exchange for 6 hours at 60℃. Remove the exchange solution. Wash with demineralized water at 80℃ for 4 hours. Repeat the exchange-washing process 3 times. Take out the molecular sieve and dry it at 120℃ for 4 hours; after drying, calcine it at 470℃ for 3 hours to prepare Hβ molecular sieve raw powder. Weigh 100g of Hβ molecular sieve and 20g of boehmite, add 100g of 1% nitric acid aqueous solution in batches, knead, and then roll for 3 hours. Extrude the mixture using an extruder; then dry at 120℃ for 6 hours; calcine at 540℃ for 4 hours. After cooling, modify the mixture by adding 5% citric acid aqueous solution and exchanging for 6 hours at 60℃; wash with demineralized water at 60℃ for 3 hours. The strip-shaped molecular sieve was removed and dried at 120℃ for 4 hours; after drying, it was calcined at 540℃ for 2 hours to prepare Hβ molecular sieve adsorbent. The specific surface area was measured to be 578 m² / g, and the effective pore volume was 0.45 ml / g.

[0098] The molecular sieve adsorbent prepared in Example 23 was used to adsorb recycled hexane produced in the production of ethylene propylene rubber, thereby removing olefins. Under the conditions of a bromine value of 210 mgBr / 100g in the recycled hexane, an adsorption temperature of 50°C, a space velocity of 0.5 h⁻¹, and an adsorption pressure of 0.7 MPa, the adsorption capacity of olefins was determined to be 685 g / kg.

[0099] As can be seen from Examples 1-23 above, the molecular sieve hexane deolefination adsorbent prepared by the present invention can achieve a specific surface area (BET method) of 570-620 m². 2 With an effective pore volume of 0.45 ml / g, it features a large specific surface area and a large effective pore volume.

[0100] The molecular sieve adsorbent prepared by this invention exhibits low adsorption temperature and high adsorption capacity in the removal of olefins from recycled hexane during the production of ethylene propylene rubber. At adsorption temperatures of 20℃ to 70℃ and adsorption pressures of 0.1 MPa to 0.7 MPa, the total olefin adsorption capacity can exceed 0.685 kg / kg, and the minimum bromine value of the outlet hexane can reach 1 mgBr / 100g.

[0101] It is understood that the above specific description of the present invention is only for illustrating the present invention and is not limited to the technical solutions described in the embodiments of the present invention. Those skilled in the art should understand that modifications or equivalent substitutions can still be made to the present invention to achieve the same technical effect; as long as the use needs are met, they are all within the protection scope of the present invention.

Claims

1. The application of a molecular sieve adsorbent in the low-temperature, high-efficiency removal of olefins from hexane, characterized in that: The preparation method of this molecular sieve adsorbent is as follows: I. Preparation of Hydrogen-Form Molecular Sieves: Any one of the commercially available NaY, NaMCM-49, Naβ, and NaMCM-22 molecular sieve powders is used. The powder is exchanged with an exchange solution, and the exchange-washing process is repeated three times. The mixture is then dried and calcined to obtain hydrogen-form molecular sieves. The exchange solution is any one of the following: 1%-5% nitric acid aqueous solution, 2%-10% NH4NO3 aqueous solution, and 1%-5% citric acid aqueous solution. The exchange temperature is 60-80℃, and the exchange time is 4-6 hours. The washing time is 4-6 hours. The drying temperature is 110-120℃, and the drying time is 4-8 hours. The calcination temperature is 450-500℃, and the calcination time is 2-4 hours. II. Molding: Hydrogen-type molecular sieves, pseudoboehmite, and 1% nitric acid aqueous solution are mixed in a mass ratio of 100:15-25:

100. The mixture is then kneaded, rolled, extruded, dried, and calcined to obtain strip-shaped molecular sieves. The kneading time is 2-4 hours, the rolling time is 2-4 hours, the drying temperature is 110-120℃, the drying time is 4-8 hours, and the calcination temperature is 500-540℃, the calcination time is 4-8 hours. III. Modification: A molecular sieve adsorbent is prepared by exchanging the strip-shaped molecular sieve with an exchange solution, washing with demineralized water, drying, and calcining. The exchange solution is any one of the following: 1%-5% nitric acid aqueous solution, 2%-10% NH4NO3 aqueous solution, and 1%-5% citric acid aqueous solution. The exchange temperature is 60-80℃, the exchange time is 4-6 hours, the washing time is 4-6 hours, the drying temperature is 110-120℃, the drying time is 4-8 hours, and the calcination temperature is 450-500℃, the calcination time is 2-4 hours. The molecular sieve adsorbent obtained in step three is used to remove olefins from recycled hexane in the production of ethylene propylene rubber. The adsorption temperature is 20 ℃~70 ℃, the adsorption pressure is 0.1 MPa~0.7 MPa, and the olefin adsorption capacity is ≥672g / kg.

2. The application of the molecular sieve adsorbent according to claim 1 in low-temperature, high-efficiency hexane olefin removal, characterized in that: The preparation of the hydrogen-type molecular sieve in step one uses NaMCM-49 molecular sieve raw powder.

3. The application of the molecular sieve adsorbent according to claim 1 in low-temperature, high-efficiency hexane olefin removal, characterized in that: The exchange solution used in step one of the hydrogen-type molecular sieve preparation process is a 2%-3% nitric acid aqueous solution.

4. The application of the molecular sieve adsorbent according to claim 1 in low-temperature, high-efficiency hexane olefin removal, characterized in that: The exchange temperature in step one of the hydrogen-type molecular sieve preparation process is 60-70℃, and the exchange time is 4h.

5. The application of the molecular sieve adsorbent according to claim 1 in low-temperature, high-efficiency hexane olefin removal, characterized in that: The washing temperature in step one of the hydrogen-type molecular sieve preparation process is 60-80℃, and the washing time is 4 hours.

6. The application of the molecular sieve adsorbent according to claim 1 in low-temperature, high-efficiency hexane olefin removal, characterized in that: The calcination temperature in step one of the hydrogen-type molecular sieve preparation process is 470-500℃, and the calcination time is 3h.

7. The application of the molecular sieve adsorbent according to claim 1 in low-temperature, high-efficiency hexane olefin removal, characterized in that: In the second step of the molding process, the mass ratio of hydrogen molecular sieve: pseudoboehmite: 1% nitric acid aqueous solution is 100:20:

100.

8. The application of the molecular sieve adsorbent according to claim 1 in low-temperature, high-efficiency hexane olefin removal, characterized in that: The kneading time in step two of the forming process is 3 hours, and the rolling time is 3 hours.

9. The application of the molecular sieve adsorbent according to claim 1 in low-temperature, high-efficiency hexane olefin removal, characterized in that: The calcination temperature in step two of the molding process is 520-540℃, and the calcination time is 4 hours.

10. The application of the molecular sieve adsorbent according to claim 1 in low-temperature, high-efficiency hexane olefin removal, characterized in that: The exchange solution used in step three of the modification process is a 1%-3% nitric acid aqueous solution.

11. The application of the molecular sieve adsorbent according to claim 1 in low-temperature, high-efficiency hexane olefin removal, characterized in that: The exchange temperature in the modification process of step three is 60-80℃, and the exchange time is 4-6h.

12. The application of the molecular sieve adsorbent according to claim 1 in low-temperature, high-efficiency hexane olefin removal, characterized in that: The calcination temperature in step three of the modification process is 450-500℃, and the calcination time is 2-4 hours.