Renewable adsorbent for naphtha adsorption separation as well as preparation method and application thereof

Abstract

The invention relates to a renewable adsorbent for naphtha adsorption separation and a preparation method and application thereof. The preparation method comprises the following steps: uniformly mixing 100 parts by weight of 4A molecular sieve raw powder, 3.5-6 parts by weight of kaolin, 3.5-6 parts by weight of pseudo-boehmite and 5-7 parts by weight of methyl cellulose, putting 15 parts by weight of mixed powder into a rolling-ball pot, screening out 0.5-1.4 mm particles under the working condition of rotary liquid spraying of the rolling-ball pot, drying, roasting at high temperature and keeping constant temperature, mixing with 3% potassium hydroxide according to a solid-to-liquid ratio of 1: 6, and uniformly stirring to obtain the 4A molecular sieve catalyst. And putting the particles into a high-pressure reaction kettle, discharging and washing, putting the washed particles into a calcium salt solution with the concentration of 8-12% according to the solid-to-liquid ratio of 1: 8, cleaning, draining, drying, roasting at high temperature, keeping constant temperature, and packaging while hot, thereby obtaining the renewable adsorbent for naphtha adsorption separation. The renewable adsorbent is applied to a naphtha hydrocarbon adsorption separation method, a hydrogen source is not needed, after the service life of the adsorbent expires, an in-device regeneration method is adopted, the activity is recovered, and the defect that an existing adsorbent is short in service life is overcome.

Description

Technical Field

[0001] The invention relates to the technical field of petrochemical industry, and in particular to a regenerable adsorbent for naphtha adsorption separation, and a preparation method and application thereof. Background Art

[0002] Conventional naphtha contains hydrocarbons such as normal alkanes, isoalkanes, cycloalkanes and aromatics, some of which contain small or trace amounts of olefins, as well as impurities such as sulfur, nitrogen, water, and oxygen-containing compounds. In industrial production, naphtha needs to be refined to remove impurities and then separated into high-purity normal alkanes and the rest of the high-octane mixture (isoalkanes, cycloalkanes and aromatics). The main uses of normal alkanes are: vegetable oil extractants, polymer solvents, cleaning agents, etc., and the high-octane mixture of isoalkanes, cycloalkanes and aromatics is mainly used as reforming materials, gasoline blending materials, etc.

[0003] There are three main methods for the existing naphtha hydrocarbon separation technology: 1) hydrofining naphtha at high temperature and high pressure, and then separating it through multi-tower distillation; 2) after hydrofining, it is separated by fixed bed adsorption; 3) after hydrofining, it is separated by simulated moving bed. Among them, the combined technology of hydrofining and simulated moving bed adsorption separation is complicated to start and stop the device, and the cost of adsorbent replacement is high. At the same time, the device must have a hydrogen source, which is complicated to operate and has high production costs, which is not conducive to the sustainable development of the naphtha hydrocarbon separation industry. Therefore, it is urgent to develop a renewable adsorbent for naphtha adsorption separation and apply it to the naphtha hydrocarbon adsorption separation method. Summary of the invention

[0004] In view of the above-mentioned technical deficiencies, the purpose of the present invention is to provide a regenerable adsorbent for the adsorption and separation of naphtha hydrocarbons and a preparation method and application thereof, which does not require a hydrogen source and uses a special adsorbent to adsorb and separate the refined naphtha to obtain a mixture of normal alkanes and high-octane isoalkanes, aromatics, and cycloalkanes. The adsorbent is regenerable, which reduces the start-up and shutdown procedures and agent replacement, is easy to operate, and allows for resource recycling.

[0005] In order to achieve the above object, the present invention provides the following technical solutions: A renewable adsorbent for naphtha adsorption separation, the raw materials comprising: by weight, 100 parts of 4A molecular sieve powder, 3.5-6 parts of kaolin, 3.5-6 parts of pseudo-boehmite, and 5-7 parts of methyl cellulose; the 4A molecular sieve powder has a burning reduction of 20-22% at 600°C; the kaolin has a burning reduction of 30% at 600°C; the pseudo-boehmite has a burning reduction of 30% at 600°C, a specific surface area of ​​260m2 / g, and a pore volume of 0.6ml / g.

[0006] The present invention also provides a method for preparing the above-mentioned regenerable adsorbent for naphtha adsorption separation, comprising the following steps: S1. Select sodium hydroxide, sodium aluminate and sodium silicate as basic raw materials, and the synthesis conditions are: Na2O:AI2O3:SiO2:H2O=4:1:1.95:300, temperature 115-125°C, pressure 0.15-0.25MPa, constant temperature for 4-5 hours, discharge, wash with water until the pH is below 11, obtain 4A molecular sieve raw powder, and dry it for standby use; S2, take 100 parts by weight of 4A molecular sieve powder, 3.5-6 parts by weight of kaolin, 3.5-6 parts by weight of pseudo-boehmite, 5-7 parts by weight of methyl cellulose, mix all the materials evenly, take 15 parts by weight of the mixed powder and put it into the rolling ball pot, rotate the pot body, and continuously spray water into the pot. The mixed powder gradually aggregates into particles under the working condition of the rolling ball pot rotating and spraying liquid, and sieve out 0.2-0.5mm particles as seed balls; S3, put the seed balls into the rolling pot, rotate the pot, continuously add the mixed powder and spray water into the pot, and the two are circulated alternately. The seed balls gradually become larger under the working conditions of the rolling pot rotating and spraying liquid; when the particles reach 1.4mm, the rolling pot stops rotating, and the particles of 0.5-1.4mm are screened out, dried at 150-200℃ for 2-4 hours, and then high-temperature roasted according to the program, respectively at 200℃, 300℃, and 550-600℃ for 1-2 hours; S4, the high-temperature roasted particles are spread on a plate, placed in the open air for more than 48 hours, mixed with 3% potassium hydroxide at a solid-liquid ratio of 1:6, put into a high-pressure reactor, heated to 120-125 degrees, pressure 0.20-0.26MPa, kept at a constant temperature for 3-4 hours, discharged, and washed with water until the pH is below 10; S5. The washed particles are added into a calcium salt solution with a concentration of 8-12% at a solid-liquid ratio of 1:8. The pH value of the calcium salt solution is controlled to be 10-12, and the temperature is 70-80°C. The solution is kept at this temperature for 2 hours. Then, the salt on the surface and inside the particles is rinsed clean and filtered. The filtered particles are dried at 150-200°C for 2-4 hours, and then calcined at high temperature according to a procedure, and kept at 200°C, 300°C, and 550-600°C for 1-2 hours respectively. The particles are packaged while hot to obtain a renewable adsorbent for naphtha adsorption separation.

[0007] The present invention also provides an application of the above-mentioned regenerable adsorbent for naphtha adsorption separation in a method for adsorption separation of naphtha hydrocarbons, comprising the following steps: Step 1, loading the prepared regenerable adsorbent for naphtha adsorption separation into a 24-layer simulated moving bed of an adsorption tower, heating the refined naphtha and inputting it into the adsorption tower, controlling the tower temperature at 150-180°C and the pressure at 1-2Mpa; using normal carbon 10, normal carbon 11 or normal carbon 12 as the desorbent, and using undecanoic acid or dodecanes as the flushing liquid; and obtaining a mixture of normal alkanes and isoalkanes, aromatic hydrocarbons and cycloalkanes according to the operation of the simulated moving bed; Step 2, during operation, when the recovery rate of normal alkanes drops to 95% and the purity is less than 98%, stop feeding, blow dry the oil in the adsorption tower with nitrogen, introduce heated nitrogen from the top of the adsorption tower, slowly raise the temperature, and when the temperature in the tower reaches above 400°C, introduce a mixture of purified air and nitrogen to control the oxygen content to ensure that the initial oxygen content is 0.4-0.8%; keep the temperature rising slowly again, continuously increase the oxygen content and temperature, and finally control the temperature to 520-527°C and the oxygen content to 3-5.9%. Keep the temperature constant for 8 hours, the adsorbent recovers its activity, and continue to carry out naphtha adsorption separation.

[0008] Preferably, in step 1, the bed is divided into 4 major zones, namely zone I - feed zone (7 layers), zone II - refining zone (8 layers), zone III - desorption zone (7 layers), zone IV - buffer zone (2 layers); The beneficial effects of the present invention are as follows: the present invention proposes a regenerable adsorbent for naphtha adsorption separation, and a preparation method and application thereof; the regenerable adsorbent for naphtha adsorption separation is used, and after the life of the adsorbent expires, an in-vessel regeneration method is used to restore the activity, thereby overcoming the defects of the existing adsorbents, such as short service life, frequent start-up and shutdown procedures, and agent replacement; at the same time, the regenerable adsorbent for naphtha adsorption separation is used, and the refined naphtha can be adsorbed and separated in the absence of a hydrogen source to obtain a mixture of normal alkanes and high-octane isoalkanes, aromatics, and cycloalkanes; the operation is simple, the energy consumption is low, resources are recycled, the production cost is reduced, and the economic benefit is improved.

[0009] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the preferred embodiments of the present invention are described in detail as follows. DETAILED DESCRIPTION

[0010] The technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0011] The present invention discloses a regenerable adsorbent for naphtha adsorption separation and a preparation method and application thereof. Those skilled in the art can refer to the content of this article and appropriately improve the process parameters to achieve it. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art, and they are all deemed to be included in the present invention. The regenerable adsorbent for naphtha adsorption separation and a preparation method and application thereof described in the present invention have been described through embodiments, and relevant personnel can obviously modify or appropriately change and combine the methods and applications described herein without departing from the content, spirit and scope of the present invention to realize and apply the technology of the present invention.

[0012] The technical solutions described in the present invention, unless otherwise specified, are all conventional solutions in the art; the reagents or materials described, unless otherwise specified, are all from commercial channels.

[0013] The following further describes a regenerable adsorbent for naphtha adsorption separation provided by the present invention, and its preparation method and application. Example 1

[0014] First, the preparation of 4A molecular sieve raw powder. Sodium hydroxide, sodium aluminate, and sodium silicate are selected as the basic raw materials for synthesizing 4A molecular sieve raw powder. The synthesis conditions are: Na2O: AI2O3: SiO2: H2O = 4: 1: 1.95: 300, temperature 120 ° C, pressure 0.24 MPa, constant temperature for 5 hours, discharge, wash with water until the pH is 9, obtain 4A molecular sieve raw powder, and dry it for use.

[0015] Secondly, the preparation of renewable adsorbent for naphtha adsorption separation. Weigh 100 kg of 4A molecular sieve powder, at 600 ° C, the ignition reduction is 20%; weigh 6 kg of kaolin, at 600 ° C, the ignition reduction is 30%, 6 kg of pseudo-boehmite, at 600 ° C, the ignition reduction is 30%, the specific surface area is 260m2 / g, the pore volume is 0.6ml / g, and 5 kg of methyl cellulose. Mix all the materials for 1 hour. After mixing evenly, weigh 15 kg of the mixed powder and put it into the rolling ball pot. Rotate the pot to keep the powder flowing, and continuously spray water into the pot to mix. The powder gradually gathers into particles under the working condition of the rolling ball pot rotating and spraying liquid. When the particles reach between 0.2-0.5mm, the rolling ball pot stops rotating and screens them to obtain 0.2-0.5mm balls as seed balls. The seed balls are put into the rolling ball pot, the pot body is rotated, and the mixed powder and water are continuously added to the pot. The two are circulated alternately to keep the material in the pot with a certain humidity and the granular material rolls smoothly. The particles of the seed balls gradually become larger under the working condition of the rolling ball pot rotating and spraying liquid. When the particles reach 1.4 When the ball size is 0.5-1.4 mm, the ball rolling pot stops rotating and sieving is performed to obtain particles of 0.5-1.4 mm, which are dried at 200°C for 2 hours, and then high-temperature roasted according to the program, and kept at 200°C, 300°C, and 600°C for 1 hour respectively; the balls after high-temperature roasting are spread on a plate, left in the open air for 48 hours, and then mixed with 3% potassium hydroxide at a solid-liquid ratio of 1:6, and put into a high-pressure reactor, heated to 125 degrees, pressure 0.25MPa, kept at a constant temperature for 4 hours, discharged, and washed with water. to a pH of 10; the washed particles are put into a calcium salt solution with a concentration of 8% according to a solid-liquid ratio (weight ratio) of 1:8, the pH of the calcium salt solution is controlled to be 10, the temperature is 80°C, and the temperature is kept constant for 2 hours, then the salt on the surface and inside the particles is rinsed clean and filtered, the filtered particles are dried at 200°C for 2 hours, and then high-temperature calcined according to the procedure, and kept constant at 200°C, 300°C, and 600°C for 2 hours respectively, and packaged while hot to obtain a renewable adsorbent for naphtha adsorption separation.

[0016] Furthermore, naphtha hydrocarbons are separated by adsorption. The prepared regenerable adsorbent for naphtha adsorption separation is loaded into the 24-layer simulated moving bed of the adsorption tower, and the refined naphtha is heated and input into the adsorption tower. The tower temperature is controlled at 170°C and the pressure is 2Mpa. The bed is divided into 4 major zones, namely Zone I - feed zone (7 layers), Zone II - refining zone (8 layers), Zone III - desorption zone (7 layers), and Zone IV - buffer zone (2 layers). The desorbent is normal carbon 10, and the flushing liquid is 11-isoalkanes. According to the operation of the simulated moving bed, a mixture of normal alkanes and isoalkanes, aromatics, and cycloalkanes is obtained. After a certain period of operation, the bed is divided into four zones: Zone I - feed zone (7 layers), Zone II - refining zone (8 layers), Zone III - desorption zone (7 layers), and Zone IV - buffer zone (2 layers). After the deadline, when the recovery rate of normal alkanes drops to 95% and the purity is less than 98%, the performance of the adsorbent declines, and the feeding is stopped. The oil in the adsorption tower is purged dry with nitrogen, and heated nitrogen is introduced from the top of the adsorption tower to slowly increase the temperature. When the temperature in the tower reaches 410°C, a mixture of purified air and nitrogen is introduced to control the oxygen content to ensure that the initial oxygen content is 0.4%. The temperature is kept rising slowly, and the oxygen content and temperature are continuously increased. Finally, the temperature is controlled to reach 520°C and the oxygen content reaches 5%. The temperature is kept constant for 8 hours, and the adsorbent is reactivated to continue the naphtha adsorption separation.

[0017] Example 1 Physical and chemical indicators and application results of naphtha adsorption separation adsorbent Example 2

[0018] First, the preparation of 4A molecular sieve raw powder. Sodium hydroxide, sodium aluminate, and sodium silicate are selected as the basic raw materials for synthesizing 4A molecular sieve raw powder. The synthesis conditions are: Na2O:AI2O3:SiO2:H2O=4:1:1.95:300, temperature 120℃, pressure 0.24MPa, constant temperature for 4 hours, discharge, wash with water until the pH is 9, obtain 4A molecular sieve raw powder, and dry it for use.

[0019] Secondly, the preparation of renewable adsorbent for naphtha adsorption separation. Weigh 100 kg of 4A molecular sieve powder, at 600℃, the ignition reduction is 22%; weigh 4 kg of kaolin, at 600℃, the ignition reduction is 30%, 4 kg of pseudo-boehmite, at 600℃, the ignition reduction is 30%, the specific surface area is 260m2 / g, the pore volume is 0.6ml / g, and 6 kg of methyl cellulose. Mix all the materials for 1 hour. After mixing evenly, weigh 15 kg and put it into the rolling pot. Rotate the pot to keep the powder flowing, and continuously spray water into the pot. The mixed powder is rolled in the pot. The ball pot gradually gathers into particles under the condition of rotating and spraying liquid. When the particles reach 0.2-0.5mm, the rolling ball pot stops rotating and screens to obtain 0.2-0.5mm particles as seed balls; the seed balls are put into the rolling ball pot, the pot body is rotated, and mixed powder and water are continuously added to the pot. The two are circulated alternately to keep the material in the pot with a certain humidity and the granular material rolls smoothly. The seed balls gradually become larger under the condition of rotating and spraying liquid in the rolling ball pot. When the particles reach 1.4mm The ball pot stops rotating, and sieving is performed to obtain particles of 0.5-1.4 mm, which are dried at 200°C for 2 hours, and then high-temperature roasted according to the program, and kept at 200°C, 300°C, and 600°C for 1 hour respectively; the high-temperature roasted particles are spread on a plate, placed in the open air for 48 hours, and then mixed with 3% potassium hydroxide at a solid-liquid ratio of 1:6, and put into a high-pressure reactor, heated to 125 degrees, pressure 0.26MPa, kept at a constant temperature for 4 hours, discharged, and washed with water until The pH value is 10; the washed particles are put into a calcium salt solution with a concentration of 8% according to a solid-liquid ratio (weight ratio) of 1:8, the pH value of the calcium salt solution is controlled to be 10, the temperature is 80°C, and the temperature is kept constant for 2 hours, then the salt on the surface and inside the particles is rinsed clean and filtered, the filtered particles are dried at 200°C for 2 hours, and then high-temperature calcined according to the procedure, and kept constant at 200°C, 300°C, and 600°C for 2 hours respectively, and packaged while hot to obtain a renewable adsorbent for naphtha adsorption separation.

[0020] Furthermore, naphtha hydrocarbons are separated by adsorption. The prepared adsorbent is loaded into the 24-layer simulated moving bed of the adsorption tower, and the refined naphtha is heated and input into the adsorption tower. The tower temperature is controlled at 170°C and the pressure is 2Mpa. The bed is divided into 4 large zones, namely Zone I - feed zone (7 layers), Zone II - refining zone (8 layers), Zone III - desorption zone (7 layers), and Zone IV - buffer zone (2 layers). The desorbent is normal carbon 11, and the flushing liquid is dodecaisoalkanes. According to the operation of the simulated moving bed, a mixture of normal alkanes and isoalkanes, aromatics, and cycloalkanes is obtained. After a certain period of operation, when the normal When the recovery rate of alkanes drops to 95% and the purity is less than 98%, the performance of the adsorbent declines, and the feeding is stopped. The oil in the adsorption tower is purged dry with nitrogen, and heated nitrogen is introduced from the top of the adsorption tower to slowly increase the temperature. When the temperature in the tower reaches 430°C, a mixture of purified air and nitrogen is introduced to control the oxygen content to ensure that the initial oxygen content is 0.5%. The temperature is kept rising slowly, and the oxygen content and temperature are continuously increased. Finally, the temperature is controlled to reach 522°C and the oxygen content reaches 5.3%. The temperature is kept constant for 8 hours, and the adsorbent is reactivated to continue the naphtha adsorption separation.

[0021] Example 2 Physical and chemical indicators and application results of naphtha adsorption separation adsorbent Example 3

[0022] First, the preparation of 4A molecular sieve raw powder. Sodium hydroxide, sodium aluminate, and sodium silicate are selected as the basic raw materials for synthesizing 4A molecular sieve raw powder. The synthesis conditions are: Na2O: AI2O3: SiO2: H2O = 4: 1: 1.95: 300, temperature 118 ° C, pressure 0.20 MPa, constant temperature for 5 hours, discharge, wash with water until the pH is 9, obtain 4A molecular sieve raw powder, and dry it for use.

[0023] Secondly, the preparation of renewable adsorbent for naphtha adsorption separation. Weigh 100 kg of 4A molecular sieve powder, the burning reduction is 22% at 600℃; weigh 4.5 kg of kaolin, the burning reduction is 30% at 600℃, 4.5 kg of pseudo-boehmite, the burning reduction is 30% at 600℃, the specific surface area is 260m2 / g, the pore volume is 0.6ml / g, and 7 kg of methyl cellulose. Mix all the materials for 1 hour. After mixing evenly, weigh 15 kg and put it into the rolling ball pot, rotate the pot to keep the powder flowing, and continuously spray water into the pot to mix the powder. Under the condition of the rolling pot rotating and spraying liquid, the particles gradually gather into particles. When the particles reach between 0.2-0.5mm, the rolling pot stops rotating and sieving is performed to obtain particles of 0.2-0.5mm as seed balls. The seed balls are poured into the rolling pot, the pot body is rotated, and the mixed powder and water are continuously added to the pot. The two are circulated alternately to keep the material in the pot with a certain humidity and the granular material rolls smoothly. The particles of the seed balls gradually grow larger under the condition of the rolling pot rotating and spraying liquid. When the particles grow to 0.5- When the particle size is 1.4mm, the ball rolling pot stops rotating and sieving is carried out. The particles of 0.5-1.4mm are sieved out and dried at 200℃ for 2 hours. Then, they are calcined at high temperature according to the procedure, and kept at 200℃, 300℃, and 600℃ for 1 hour respectively. The calcined particles are spread on a plate and placed in the open air for 72 hours. Then, they are mixed with 3% potassium hydroxide at a solid-liquid ratio of 1:6, and put into a high-pressure reactor. The temperature is raised to 125 degrees, the pressure is 0.26MPa, the temperature is kept constant for 4 hours, and the material is discharged. The washed particles are put into a 10% calcium salt solution at a solid-liquid ratio (weight ratio) of 1:8, the pH of the calcium salt solution is controlled to be 10, the temperature is 80°C, and the temperature is kept constant for 2 hours, then the salt on the surface and inside the particles is rinsed and filtered, the filtered particles are dried at 200°C for 2 hours, and then high-temperature calcined according to the procedure, respectively at 200°C, 300°C, and 600°C for 2 hours, and packaged while hot to obtain a renewable adsorbent for naphtha adsorption separation.

[0024] Furthermore, naphtha hydrocarbons are separated by adsorption. The prepared regenerable adsorbent for naphtha adsorption separation is loaded into the 24-layer simulated moving bed of the adsorption tower, and the refined naphtha is heated and input into the adsorption tower, and the tower temperature is controlled at 170°C and the pressure is 2Mpa; the bed is divided into 4 large zones, namely Zone I - feed zone (7 layers), Zone II - refining zone (8 layers), Zone III - desorption zone (7 layers), Zone IV - buffer zone (2 layers); the desorbent is normal carbon 10, and the flushing liquid is 11-isoalkanes; according to the operation of the simulated moving bed, a mixture of normal alkanes and isoalkanes, aromatics, and cycloalkanes is obtained; run for a certain period of time After the limit, when the recovery rate of normal alkanes drops to 95% and the purity is less than 98%, the performance of the adsorbent declines, and the feeding is stopped. The oil in the adsorption tower is purged dry with nitrogen, and heated nitrogen is introduced from the top of the adsorption tower to slowly increase the temperature. When the temperature in the tower reaches 430°C, a mixture of purified air and nitrogen is introduced to control the oxygen content to ensure that the initial oxygen content is 0.6%; the temperature is kept rising slowly, and the oxygen content and temperature are continuously increased. Finally, the temperature is controlled to reach 521°C and the oxygen content reaches 5.3%. The temperature is kept constant for 8 hours, the adsorbent is reactivated, and the naphtha adsorption separation is continued.

[0025] Example 3 Physical and chemical indicators and application results of naphtha adsorption separation adsorbent Example 4

[0026] First, the preparation of 4A molecular sieve raw powder. Sodium hydroxide, sodium aluminate, and sodium silicate are selected as the basic raw materials for synthesizing 4A molecular sieve raw powder. The synthesis conditions are: Na2O:AI2O3:SiO2:H2O=4:1:1.95:300, temperature 119℃, pressure 0.20MPa, constant temperature for 5 hours, discharge, wash with water until the pH is 11, obtain 4A molecular sieve raw powder, and dry it for use.

[0027] Secondly, the preparation of renewable adsorbent for naphtha adsorption separation. Weigh 100 kg of 4A molecular sieve powder, at 600 ° C, the ignition reduction is 22%; weigh 3.5 kg of kaolin, at 600 ° C, the ignition reduction is 30%, 3.5 kg of pseudo-boehmite, at 600 ° C, the ignition reduction is 30%, the specific surface area is 260m2 / g, the pore volume is 0.6ml / g, and 5 kg of methyl cellulose. Mix all the materials for 2 hours. After mixing evenly, weigh 15 kg and put it into the rolling ball pot, rotate the pot to keep the powder flowing, and continuously spray water into the pot. Mix the powder in The ball rolling pot gradually gathers into particles under the condition of rotating and spraying liquid. When the particles reach between 0.2-0.5mm, the ball rolling pot stops rotating and screens to obtain 0.2-0.5mm particles as seed balls. Put the seed balls into the ball rolling pot, rotate the pot body, and continuously add mixed powder and spray water into the pot. The two are circulated alternately to maintain a certain humidity of the material in the pot. The granular material rolls smoothly. The seed balls gradually become larger under the condition of rotating and spraying liquid in the ball rolling pot. When the particles reach 0.5-1.4mm When the ball rolling pot stops rotating, screening is carried out, and particles of 0.5-1.4mm are screened out, dried at 200℃ for 3 hours, and then the dried particles are high-temperature roasted according to the program, and kept at 200℃, 300℃, and 600℃ for 1 hour respectively; the balls after high-temperature roasting are spread on a plate, left in the open air for 48 hours, and then mixed with 3% potassium hydroxide at a solid-liquid ratio of 1:6, and put into a high-pressure reactor, heated to 125 degrees, pressure 0.26MPa, kept at a constant temperature for 4 hours, and discharged. , washed with water until the pH value is 9; the washed particles are put into a 9% calcium salt solution at a solid-liquid ratio (weight ratio) of 1:8, the pH value of the calcium salt solution is controlled to be 12, the temperature is 79°C, and the temperature is kept constant for 2 hours, and then the salt on the surface and inside the particles is rinsed and filtered, the filtered particles are dried at 200°C for 2 hours, and then high-temperature calcined according to the procedure, respectively at 200°C, 300°C, and 600°C for 2 hours, and packaged while hot to obtain a renewable adsorbent for naphtha adsorption separation.

[0028] Furthermore, naphtha hydrocarbons are separated by adsorption. The prepared regenerable adsorbent for naphtha adsorption separation is loaded into the 24-layer simulated moving bed of the adsorption tower, and the refined naphtha is heated and input into the adsorption tower, and the tower temperature is controlled at 170°C and the pressure is 2Mpa; the bed is divided into 4 large zones, namely Zone I - feed zone (7 layers), Zone II - refining zone (8 layers), Zone III - desorption zone (7 layers), Zone IV - buffer zone (2 layers); the desorbent is normal carbon 10, and the flushing liquid is 11-isoalkanes; according to the operation of the simulated moving bed, a mixture of normal alkanes and isoalkanes, aromatics, and cycloalkanes is obtained; run for a certain period of time After the limit, when the recovery rate of normal alkanes drops to 95% and the purity is less than 98%, the performance of the adsorbent declines, and the feeding is stopped. The oil in the adsorption tower is purged dry with nitrogen, and heated nitrogen is introduced from the top of the adsorption tower to slowly increase the temperature. When the temperature in the tower reaches 410°C, a mixture of purified air and nitrogen is introduced to control the oxygen content to ensure that the initial oxygen content is 0.8%; the temperature is kept rising slowly, and the oxygen content and temperature are continuously increased. Finally, the temperature is controlled to reach 527°C and the oxygen content reaches 5.9%. The temperature is kept constant for 8 hours, the adsorbent is reactivated, and the naphtha adsorption separation is continued.

[0029] Example 4 Physical and chemical indicators and application results of naphtha adsorption separation adsorbent

[0030] In summary, the present invention provides a regenerable adsorbent for naphtha adsorption separation, and a preparation method and application thereof. The regenerable adsorbent for naphtha adsorption separation is used. After the life of the adsorbent expires, an in-vessel regeneration method is used to restore the activity, thereby overcoming the defects of the existing adsorbents, such as short service life, frequent start-up and shutdown procedures, and agent replacement. At the same time, the regenerable adsorbent for naphtha adsorption separation can be used to adsorb and separate the refined naphtha in the absence of a hydrogen source to obtain a mixture of normal alkanes and high-octane isoalkanes, aromatics, and cycloalkanes. The operation is simple, the energy consumption is low, resources are recycled, the production cost is reduced, and the economic benefit is improved.

[0031] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0032] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A regenerable adsorbent for naphtha adsorption separation, characterized in that: The raw materials include: by weight, 100 parts of 4A molecular sieve powder, 3.5-6 parts of kaolin, 3.5-6 parts of pseudo-boehmite, and 5-7 parts of methyl cellulose.

2. A method for preparing a regenerable adsorbent for naphtha adsorption separation as claimed in claim 1, characterized in that: The steps include: S1. Select sodium hydroxide, sodium aluminate and sodium silicate as basic raw materials, and the synthesis conditions are: Na2O:AI2O3:SiO2:H2O=4:1:1.95:300, temperature 115-125°C, pressure 0.15-0.25MPa, constant temperature for 4-5 hours, discharge, wash with water until the pH is below 11, obtain 4A molecular sieve raw powder, and dry it for standby use; S2, take 100 parts by weight of 4A molecular sieve powder, 3.5-6 parts by weight of kaolin, 3.5-6 parts by weight of pseudo-boehmite, 5-7 parts by weight of methyl cellulose, mix all the materials evenly, take 15 parts by weight of the mixed powder and put it into the rolling ball pot, rotate the pot body, and continuously spray water into the pot. The mixed powder gradually aggregates into particles under the working condition of the rolling ball pot rotating and spraying liquid, and sieve out 0.2-0.5mm particles as seed balls; S3, put the seed balls into the rolling pot, rotate the pot, continuously add the mixed powder and spray water into the pot, and the two are circulated alternately. The seed balls gradually become larger under the working conditions of the rolling pot rotating and spraying liquid; when the particles reach 1.4mm, the rolling pot stops rotating, and the particles of 0.5-1.4mm are screened out, dried at 150-200℃ for 2-4 hours, and then high-temperature roasted according to the program, respectively at 200℃, 300℃, and 550-600℃ for 1-2 hours; S4, the high-temperature roasted particles are spread on a plate, placed in the open air for more than 48 hours, mixed with 3% potassium hydroxide at a solid-liquid ratio of 1:6, put into a high-pressure reactor, heated to 120-125 degrees, pressure 0.20-0.26MPa, kept at a constant temperature for 3-4 hours, discharged, and washed with water until the pH is below 10; S5. The washed particles are added into a calcium salt solution with a concentration of 8-12% at a solid-liquid ratio of 1:

8. The pH value of the calcium salt solution is controlled to be 10-12, and the temperature is 70-80°C. The solution is kept at this temperature for 2 hours. Then, the salt on the surface and inside the particles is rinsed clean and filtered. The filtered particles are dried at 150-200°C for 2-4 hours, and then calcined at high temperature according to a procedure, and kept at 200°C, 300°C, and 550-600°C for 1-2 hours respectively. The particles are packaged while hot to obtain a renewable adsorbent for naphtha adsorption separation.

3. Use of the regenerable adsorbent for naphtha adsorption separation according to any one of claims 1 to 2 in a method for adsorption separation of naphtha hydrocarbons, characterized in that: The steps include: Step 1, loading the prepared regenerable adsorbent for naphtha adsorption separation into a 24-layer simulated moving bed of an adsorption tower, heating the refined naphtha and inputting it into the adsorption tower, controlling the tower temperature at 150-180°C and the pressure at 1-2Mpa; using normal carbon 10, normal carbon 11 or normal carbon 12 as the desorbent, and using undecanoic acid or dodecanes as the flushing liquid; and obtaining a mixture of normal alkanes and isoalkanes, aromatic hydrocarbons and cycloalkanes according to the operation of the simulated moving bed; Step 2, during operation, when the recovery rate of normal alkanes drops to 95% and the purity is less than 98%, stop feeding, blow dry the oil in the adsorption tower with nitrogen, introduce heated nitrogen from the top of the adsorption tower, slowly increase the temperature, and when the temperature in the tower reaches above 400°C, introduce a mixture of purified air and nitrogen to control the oxygen content to ensure that the initial oxygen content is 0.4-0.8%; keep the temperature rising slowly again, continuously increase the oxygen content and temperature, and finally control the temperature to 520-527°C and the oxygen content to 3-5.9%. Keep the temperature constant for 8 hours, the adsorbent recovers its activity, and continue to carry out naphtha adsorption separation.

4. The use of a regenerable adsorbent for naphtha adsorption separation as claimed in claim 3 in a method for adsorption separation of naphtha hydrocarbons, characterized in that: In the step 1, the 24-layer simulated moving bed is divided into 4 major zones, namely zone I - feed zone (7 layers), zone II - refining zone (8 layers), zone III - desorption zone (7 layers), zone IV - buffer zone (2 layers).

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