Low-temperature regeneration method for diesel oil adsorbent

Abstract

Disclosed in the present invention is a low-temperature regeneration method for a diesel oil adsorbent. The method comprises the steps of: S1, using nitrogen to purge a diesel oil raw material in a bed layer at a low temperature; S2, subjecting an inactivated diesel oil adsorbent in the bed layer to low-temperature solvent flushing and regeneration with a liquid-phase composite solvent; S3, subjecting the bed layer to low-temperature purging with nitrogen, so as to remove the liquid-phase composite solvent from voids in the bed layer; S4, subjecting the bed layer to high-temperature purging with nitrogen, so as to remove the liquid-phase composite solvent from the inactivated diesel oil adsorbent; and S5, subjecting the bed layer to low-temperature purging with nitrogen, and reducing the temperature of the bed layer to an adsorption temperature to complete adsorbent regeneration. The process flow of the present invention is simple, and a regenerated adsorbent exhibits a small decrease in the adsorption performance and has a high regeneration stability.

Description

A Low-Temperature Regeneration Method for Diesel Adsorbent Technical Field

[0001] This invention relates to a process for regenerating adsorbents, specifically a low-temperature regeneration method for diesel adsorbents. Background Technology

[0002] The removal of aromatics from diesel fuel by adsorption has been studied for many years. However, highly polar impurities such as sulfur and nitrogen compounds and gums in diesel fuel can deactivate the adsorbent, causing it to lose its selective adsorption capacity for aromatics. Currently, adsorbent regeneration processes still face problems such as difficulty in regenerating the adsorbent, decreased adsorption performance after regeneration, and high energy consumption during the regeneration process.

[0003] CN111996030A discloses a process for in-situ regeneration of adsorbents in a simulated moving bed. It uses weakly polar solvents and strongly polar solvents to perform in-situ steam regeneration of deactivated adsorbents in a simulated moving bed device. However, the weak / strong polar solvents result in high regeneration temperatures, narrow applicability, and low regenerated capacity.

[0004] CN107790112A discloses an activation method for an adsorbent to remove oxygen-containing compounds from low-carbon olefins. This method removes low-carbon oxygen-containing compounds from the adsorbent through a step-by-step temperature-progression purging process, avoiding coking and carbon buildup on the adsorbent. However, the processing range is narrow, and it can only process low-carbon oxygen-containing compounds such as methanol and dimethyl ether.

[0005] CN107321337A discloses an adsorbent regeneration system and a method for adsorbent regeneration. The regeneration system mainly includes a regeneration furnace, a condenser, a gas-liquid separator, and a vacuum pump. The adsorbent is placed in a regeneration furnace at 420–460°C, and nitrogen is introduced through the inlet pipe for purging for 1–2 hours, followed by nitrogen calcination regeneration. CN108795476A discloses a gasoline desulfurization adsorbent regeneration process. This method involves initial regeneration via a fluidized bed, followed by placement in a high-temperature heating furnace, introduction of oxygen, heating to 500–600°C, and calcination for 2–5 hours to complete adsorbent regeneration. Both of these methods employ high-temperature calcination to remove deactivated substances from the adsorbent, resulting in high regeneration efficiency but also posing a risk of adsorbent structure damage and high energy consumption.

[0006] Existing adsorbent regeneration processes mainly consist of external regeneration in a high-temperature calciner and in-situ regeneration in a high-temperature gas environment. External regeneration suffers from problems such as frequent loading and unloading of adsorbents, high energy consumption, and large resource consumption. In-situ regeneration in a high-temperature gas environment is complex, and the adsorption capacity and adsorption separation performance decrease significantly after regeneration, making it difficult to meet separation standards. Summary of the Invention

[0007] This invention is proposed to address the problems of high temperature, high energy consumption, poor stability, severe degradation of adsorption performance after regeneration, and low adsorption capacity in existing diesel adsorbent regeneration methods. Its purpose is to provide a low-temperature regeneration method for diesel adsorbents.

[0008] This invention is achieved through the following technical solution:

[0009] A low-temperature regeneration method for diesel adsorbent includes the following steps:

[0010] S1. The diesel feedstock in the bed is purged with nitrogen at low temperature.

[0011] S2. Low-temperature solvent flushing and regeneration of the deactivated diesel adsorbent in the bed is performed using a liquid-phase composite solvent.

[0012] S3. Nitrogen gas is used to purge the bed at low temperature to remove the liquid-phase composite solvent in the bed gaps;

[0013] S4. Nitrogen gas is used to purge the bed at high temperature to remove the liquid-phase composite solvent in the deactivated diesel adsorbent.

[0014] S5. Nitrogen gas is used to purge the bed at low temperature to reduce the bed temperature to the adsorption temperature, thus completing the regeneration of the adsorbent.

[0015] The beneficial effects of this invention are:

[0016] This invention provides a low-temperature regeneration method for diesel adsorbents, which features low regeneration temperature and low process energy consumption. The liquid-phase composite solvent can efficiently remove poisons from the diesel adsorbent with a low agent-to-oil ratio. The liquid-phase composite solvent can form a minimum azeotrope, which significantly reduces the regeneration temperature during high-temperature N2 purging and completely removes the composite solvent from the adsorbent, resulting in high regeneration efficiency. The adsorption capacity (mass) loss of the diesel adsorbent after the first regeneration is ≤3%, and the adsorption capacity (mass) loss is ≤20% within 20 regenerations. Attached Figure Description

[0017] Figure 1 is a schematic diagram of the system used in the low-temperature regeneration method of diesel adsorbent of the present invention.

[0018] in:

[0019] 1. Rinse liquid tank; 2. Solvent regeneration tower; 3. Pump I; 4. Rinse solvent collection tank; 5. Adsorption device; 6. N2 heater; 7. Diesel feedstock collection tank; 8. N2 flow meter; 9. Pump II.

[0020] For those skilled in the art, other related figures can be obtained from the above figures without any creative effort. Detailed Implementation

[0021] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0022] As shown in Figure 1, a method for low-temperature regeneration of diesel adsorbent includes the following steps:

[0023] S1. Nitrogen cryogenic purging is used to purge the diesel feedstock in the bed.

[0024] Nitrogen feedstock is used to purge the deactivated diesel adsorbent in the adsorption device 5 at low temperature via N2 flow meter 8 and N2 heater 6. The diesel feedstock in the adsorption device 5 then enters the collection tank 7 for collection.

[0025] In step S1, the nitrogen cryogenic purging temperature is 40℃~80℃, and the nitrogen purging space velocity is 100h. -1 ~500h -1 The nitrogen purging pressure is 0.1 MPa to 0.3 MPa, and the purging time is 30 min to 150 min; preferably, the nitrogen cryogenic purging space velocity is 150 h⁻¹. -1 ~350h -1 The N2 purging pressure is 0.1MPa to 0.2MPa, and the purging time is 40min to 80min.

[0026] S2. Low-temperature solvent flushing and regeneration of the deactivated diesel adsorbent in the bed is performed using a liquid-phase composite solvent.

[0027] The liquid phase composite solvent in the rinsing tank 1 is used by pump II 9 to regenerate the deactivated adsorbent in the adsorption device 5 by low-temperature solvent rinsing.

[0028] The rinsing and regeneration temperature in step S2 is 40℃~80℃; the rinsing space velocity of the liquid-phase composite solvent is 0.1h. - ~2.0h -1 The flushing pressure is 0.1 MPa to 0.3 MPa, and the volume ratio of the liquid-phase composite solvent to the deactivated diesel adsorbent is (1.0 to 2.5):1. The liquid-phase composite solvent in step S2 includes aromatics and oxygen-containing compounds. Aromatics are used as a co-solvent to dissolve oxygen-containing compounds and diesel. The boiling point of aromatics is ≤150℃, and the boiling point of oxygen-containing compounds is ≤90℃. Aromatics can form a minimum azeotrope with oxygen-containing compounds. The content of aromatics in the liquid-phase composite solvent is 10% to 30%.

[0029] S3. The bed is purged with nitrogen at low temperature to remove the liquid-phase composite solvent in the bed gaps.

[0030] After the nitrogen feedstock is flushed through the N2 flow meter 8 and the N2 heater 6, the adsorbent is purged at low temperature, and the flushing solvent in the adsorption device 5 enters the collection tank 4 for collection.

[0031] In step S3, nitrogen is used to purge the bed at a temperature of 40°C to 80°C, and the nitrogen purge space velocity is 100 h⁻¹. -1 ~500h -1 The N2 purging pressure is 0.1 MPa to 0.3 MPa, and the purging time is 30 min to 150 min; preferably, the nitrogen cryogenic purging space velocity is 150 h⁻¹. -1 ~350h -1 The N2 purging pressure is 0.1MPa to 0.2MPa, and the purging time is 40min to 80min.

[0032] S4. High-temperature purging of the bed with nitrogen gas is used to remove the liquid-phase composite solvent in the deactivated diesel adsorbent.

[0033] After the nitrogen feedstock is flushed through the N2 flow meter 8 and the N2 heating furnace 6, the adsorbent is purged at high temperature to remove the residual flushing solvent from the adsorbent.

[0034] In step S4, the bed is purged with nitrogen at a temperature of 100℃~160℃, and the nitrogen purge space velocity is 100 h⁻¹. -1 ~500h -1 The nitrogen purging pressure is 0.1 MPa to 0.3 MPa, and the purging time is 30 min to 150 min; preferably, the nitrogen high-temperature purging space velocity is 300 h⁻¹. -1 ~450h -1 The nitrogen purging pressure is 0.15MPa to 0.25MPa, and the purging time is 50min to 120min.

[0035] S5. The bed is purged with nitrogen at low temperature to lower the bed temperature to the adsorption temperature, thus completing the adsorbent regeneration.

[0036] Nitrogen feed is used to purge the adsorbent in the adsorption unit 5 after high-temperature purging through N2 flow meter 8 and N2 heating furnace 6, thereby reducing the bed temperature to the adsorption temperature and completing the regeneration of the adsorbent.

[0037] In step S5, nitrogen is used to purge the bed at a temperature of 40°C to 80°C, and the nitrogen purge space velocity is 100 h⁻¹. -1 ~500h -1 The N2 purging pressure is 0.1 MPa to 0.3 MPa, and the purging time is 30 min to 150 min; preferably, the nitrogen cryogenic purging space velocity is 150 h⁻¹. -1 ~350h -1 The N2 purging pressure is 0.1MPa to 0.2MPa, and the purging time is 40 to 80 minutes.

[0038] S6. The composite solvent containing diesel feedstock is recovered and reused through distillation separation.

[0039] The composite solvent containing diesel feedstock enters the distillation column 2 from the collection tank 4 via pump I 3 to regenerate the flushing solvent. The liquid composite solvent collected from the top of the distillation column 2 is returned to the flushing liquid tank 1.

[0040] In step S6, during the distillation process to recover the solvent, the theoretical number of distillation columns is 30 to 50, the reflux ratio is 0.3 to 1.2, the solvent mass loss is ≤0.1%, and the purity of the recovered solvent is ≥95%.

[0041] The adsorption device 5 is filled with deactivated diesel adsorbent; the diesel adsorbent is any one or a combination of several of molecular sieves, silica gel, alumina or amorphous aluminum silicate; the diesel feedstock treated by the diesel adsorbent has a distillation range of 150℃ to 365℃; the adsorption device 5 is any one of fixed bed, moving bed or simulated moving bed.

[0042] The formula for calculating the adsorption capacity (mass) of the adsorbent in the following examples is as follows:

[0043] Adsorption capacity (mass) = Diesel feedstock mass flow rate × Aromatic content × Breakthrough time / Adsorbent mass;

[0044] Loss of adsorption capacity (mass) after regeneration = (Adsorption capacity (mass) of fresh adsorbent - Adsorption capacity (mass) after regeneration) / Adsorption capacity (mass) of fresh adsorbent × 100%.

[0045] Example 1

[0046] The diesel feedstock has a distillation range of 175℃~340℃, the deactivated adsorbent is silica gel, the adsorption device is a fixed bed, and the method for low-temperature regeneration of the adsorbent includes the following steps:

[0047] S1. Nitrogen cryogenic purging of diesel feedstock in the bed, purging temperature 40℃, space velocity 150h -1 The purging pressure was 0.1 MPa, and the purging time was 40 min.

[0048] S2. The deactivated adsorbent in the bed was regenerated by low-temperature solvent washing using a liquid-phase composite solvent. The composite solvent consisted of 10% benzene and 90% ethanol, with benzene having a boiling point of 80.1℃ and ethanol having a boiling point of 78.3℃. The washing space velocity was 0.2 h⁻¹. -1 The flushing pressure was 0.1 MPa, the flushing temperature was 40℃, and the ratio of flushing solvent to deactivated adsorbent volume was 2.5:1.

[0049] S3. Low-temperature purging is performed using N2 at a purging temperature of 40°C and a space velocity of 150 h⁻¹. -1 The purging pressure was 0.1 MPa, and the purging time was 40 min.

[0050] S4. High-temperature purging is performed using N2 at a temperature of 100℃ and a space velocity of 300 h⁻¹. -1 The purging pressure was 0.15 MPa, and the purging time was 50 min.

[0051] S5. Low-temperature purging is performed using N2 at a temperature of 40°C and a space velocity of 150 h⁻¹. -1 The purging pressure was 0.1 MPa, and the purging time was 60 min.

[0052] S6. The composite solvent containing diesel feedstock is recovered and reused through distillation separation. The theoretical number of distillation columns is 30, and the reflux ratio is 0.45.

[0053] Results of Example 1: The adsorption capacity (mass) loss was 2.5% after the first regeneration, 19.5% after 19 regenerations, and 21.4% after 21 regenerations. The mass loss during solvent recovery was 0.02%, and the purity of the recovered solvent was 96.5%.

[0054] Example 2

[0055] The diesel feedstock has a distillation range of 160℃~360℃, the deactivated adsorbent is a molecular sieve, the adsorption device is a simulated moving bed, and the method for low-temperature regeneration of the adsorbent includes the following steps:

[0056] S1. Nitrogen cryogenic purging of diesel feedstock in the bed, purging temperature 60℃, space velocity 350h -1 The purging pressure was 0.2 MPa, and the purging time was 80 min.

[0057] S2. The deactivated adsorbent in the bed was regenerated by low-temperature solvent washing using a liquid-phase composite solvent. The composite solvent consisted of 30% toluene and 70% acetone. Toluene has a boiling point of 110.6℃, and acetone has a boiling point of 56.5℃. The washing space velocity was 1.5 h⁻¹. -1 The flushing pressure was 0.2 MPa, the flushing temperature was 80℃, and the volume ratio of flushing solvent to deactivated adsorbent was 1.0:1.

[0058] S3. Low-temperature purging is performed using N2 at a purging temperature of 60°C and a space velocity of 350 h⁻¹. -1 The purging pressure was 0.2 MPa, and the purging time was 80 min.

[0059] S4. High-temperature purging is performed using nitrogen (N2) at a temperature of 120°C and a space velocity of 450 h⁻¹. -1 The purging pressure was 0.2 MPa, and the purging time was 120 min.

[0060] S5. Low-temperature purging is performed using N2 at a temperature of 60°C and a space velocity of 350 h⁻¹. -1 The purging pressure was 0.2 MPa, and the purging time was 80 min.

[0061] S6. The composite solvent containing diesel feedstock is recovered and reused through distillation separation. The theoretical number of distillation columns is 35, and the reflux ratio is 0.6.

[0062] Results of Example 2: The adsorption capacity (mass) loss after the first regeneration was 1.3%, the adsorption capacity (mass) loss after 19 regenerations was 18.8%, the adsorption capacity (mass) loss after 21 regenerations was 20.7%, the mass loss during solvent recovery was 0.05%, and the purity of the recovered solvent was 97.3%.

[0063] Example 3

[0064] The diesel feedstock has a distillation range of 150℃~365℃, the deactivated adsorbent is alumina, the adsorption device is a moving bed, and the method for low-temperature regeneration of the adsorbent includes the following steps:

[0065] S1. Nitrogen cryogenic purging of diesel feedstock in the bed, purging temperature 80℃, space velocity 200 h⁻¹ -1 The purging pressure was 0.1 MPa, and the purging time was 60 min.

[0066] S2. The deactivated adsorbent in the bed was regenerated by low-temperature solvent washing using a liquid-phase composite solvent. The composite solvent consisted of 20% ethylbenzene and 80% isopropanol. Ethylbenzene has a boiling point of 136.2℃, and isopropanol has a boiling point of 82.5℃. The washing space velocity was 2 h / h. -1 The flushing pressure was 0.15 MPa, the flushing temperature was 80℃, and the volume ratio of flushing solvent to deactivated adsorbent was 1.5:1.

[0067] S3. Low-temperature purging is performed using N2 at a temperature of 80°C and a space velocity of 200 h⁻¹. -1 The purging pressure was 0.15 MPa, and the purging time was 70 min.

[0068] S4. High-temperature purging is performed using N2 at a temperature of 150°C and a space velocity of 400 h⁻¹. -1 The purging pressure was 0.2 MPa, and the purging time was 100 min.

[0069] S5. Low-temperature purging is performed using N2 at a temperature of 80°C and a space velocity of 200 h⁻¹. -1 The purging pressure was 0.15 MPa, and the purging time was 70 min.

[0070] S6. The composite solvent containing diesel feedstock is recovered and reused through distillation separation. The theoretical number of distillation columns is 45, and the reflux ratio is 1.0.

[0071] Results of Example 3: The adsorption capacity (mass) loss after the first regeneration was 3.7%, the adsorption capacity (mass) loss after 19 regenerations was 18.9%, the adsorption capacity (mass) loss after 21 regenerations was 21.0%, the mass loss during solvent recovery was 0.1%, and the purity of the recovered solvent was 98.1%.

[0072] Example 4

[0073] The diesel feedstock has a distillation range of 200℃~350℃, the deactivated adsorbent is amorphous aluminum silicate, the adsorption device is a fixed bed, and the method for low-temperature regeneration of the adsorbent includes the following steps:

[0074] S1. Nitrogen cryogenic purging of diesel feedstock in the bed, purging temperature 40℃, space velocity 175h / h -1 The purging pressure was 0.5 MPa, and the purging time was 50 min.

[0075] S2. The deactivated adsorbent in the bed was regenerated by low-temperature solvent washing using a liquid-phase composite solvent. The composite solvent consisted of 15% benzene and 85% methanol, with benzene having a boiling point of 80.1℃ and methanol having a boiling point of 64.8℃. The washing space velocity was 0.5 h⁻¹. -1 The flushing pressure was 0.15 MPa, the flushing temperature was 40℃, and the ratio of flushing solvent to deactivated adsorbent volume was 1.4:1.

[0076] S3. Low-temperature purging is performed using N2 at a purging temperature of 40°C and a space velocity of 175 h⁻¹. -1 The purging pressure was 0.5 MPa, and the purging time was 50 min.

[0077] S4. High-temperature purging is performed using nitrogen (N2) at a temperature of 110°C and a space velocity of 370 h⁻¹. -1 The purging pressure was 0.15 MPa, and the purging time was 70 min.

[0078] S5. Low-temperature purging is performed using N2 at a temperature of 40°C and a space velocity of 175 h⁻¹. -1 The purging pressure was 0.5 MPa, and the purging time was 50 min.

[0079] S6. The composite solvent containing diesel feedstock is recovered and reused through distillation separation. The theoretical number of distillation columns is 45, and the reflux ratio is 0.3.

[0080] Results of Example 4: The adsorption capacity (mass) loss after the first regeneration was 1.0%, the adsorption capacity (mass) loss after 19 regenerations was 18.3%, the adsorption capacity (mass) loss after 21 regenerations was 20.4%, the mass loss during solvent recovery was 0.06%, and the purity of the recovered solvent was 95.9%.

[0081] Comparative Example 1

[0082] The diesel feedstock has a distillation range of 150℃~365℃, the deactivated adsorbent is silica gel, the adsorption device is a fixed bed, and the method for low-temperature regeneration of the adsorbent includes the following steps:

[0083] S1. Nitrogen cryogenic purging of diesel feedstock in the bed, purging temperature 30℃, space velocity 100h -1 The purging pressure was 0.5 MPa, and the purging time was 30 min.

[0084] S2. The deactivated adsorbent in the bed was regenerated by low-temperature solvent washing using a liquid-phase composite solvent. The composite solvent consisted of 50% n-hexane and 50% benzene, with benzene having a boiling point of 80.1℃ and n-hexane having a boiling point of 69℃. The washing space velocity was 2.5 h⁻¹. -1 The flushing pressure was 0.4 MPa, the flushing temperature was 100℃, and the ratio of flushing solvent to deactivated adsorbent volume was 3.0:1.

[0085] S3. Low-temperature purging is performed using N2 at a purging temperature of 30°C and a space velocity of 100 h⁻¹. -1 The purging pressure was 0.5 MPa, and the purging time was 30 min.

[0086] S4. High-temperature purging is performed using N2 at a temperature of 200℃ and a space velocity of 200h. -1 The purging pressure was 0.5 MPa, and the purging time was 200 min.

[0087] S5. Low-temperature purging is performed using N2 at a purging temperature of 30°C and a space velocity of 100 h⁻¹. -1 The purging pressure was 0.5 MPa, and the purging time was 30 min.

[0088] S6. The composite solvent containing diesel feedstock is recovered and reused through distillation separation. The theoretical number of distillation columns is 25, and the reflux ratio is 0.2.

[0089] Comparative Example 1 Results: The adsorption capacity (mass) loss after the first regeneration was 10.4%, the adsorption capacity (mass) loss after 19 regenerations was 29.7%, the adsorption capacity (mass) loss after 21 regenerations was 34.2%, the mass loss during solvent recovery was 0.3%, and the purity of the recovered solvent was 93.5%.

[0090] Table 1 Comparison of Regeneration Results

[0091] As shown in Table 1, according to the method of the present invention, the adsorption capacity (mass) decreases by ≤5% after the first regeneration of the diesel adsorbent, and by ≤20% after 19 regenerations. Furthermore, the solvent mass loss during solvent recovery is ≤0.1%, and the solvent purity is ≥95%. Therefore, this application exhibits the characteristics of high regeneration efficiency, low regeneration temperature, and low solvent loss during regeneration.

[0092] This invention regenerates the deactivated adsorbent at a relatively low temperature by rinsing it with a polar composite solvent, and further removes the solvent by N2 purging, achieving complete regeneration of the adsorbent. The rinsing solvent can be recycled through distillation. The entire process is characterized by low temperature and low pressure, low solvent-to-oil ratio, and stable regeneration performance. The adsorption capacity loss after regeneration is less than 3%, and the solvent recovery rate is over 99.9%.

[0093] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A low-temperature regeneration method for diesel adsorbent, characterized in that: Includes the following steps: S1. The diesel feedstock in the bed is purged with nitrogen at low temperature. S2. Low-temperature solvent flushing and regeneration of the deactivated diesel adsorbent in the bed is performed using a liquid-phase composite solvent. S3. Nitrogen gas is used to purge the bed at low temperature to remove the liquid-phase composite solvent in the bed gaps; S4. Nitrogen gas is used to purge the bed at high temperature to remove the liquid-phase composite solvent in the deactivated diesel adsorbent. S5. Nitrogen gas is used to purge the bed at low temperature to reduce the bed temperature to the adsorption temperature, thus completing the regeneration of the adsorbent.

2. The low-temperature regeneration method for diesel adsorbent according to claim 1, characterized in that: In step S1, the nitrogen cryogenic purging temperature is 40℃~80℃, and the nitrogen purging space velocity is 100h. -1 ~500h -1 The nitrogen purging pressure is 0.1 MPa to 0.3 MPa, and the purging time is 30 min to 150 min; preferably, the nitrogen cryogenic purging space velocity is 150 h⁻¹. -1 ~350h -1 The N2 purging pressure is 0.1MPa to 0.2MPa, and the purging time is 40min to 80min.

3. The low-temperature regeneration method for diesel adsorbent according to claim 1, characterized in that: The rinsing and regeneration temperature in step S2 is 40℃~80℃; the rinsing space velocity of the liquid-phase composite solvent is 0.1h~2.0h. -1 The flushing pressure is 0.1 MPa to 0.3 MPa, and the volume ratio of the liquid-phase composite solvent to the deactivated diesel adsorbent is (1.0 to 2.5):

1. The liquid-phase composite solvent in step S2 includes aromatics and oxygen-containing compounds. The boiling point of the aromatics is ≤150℃, and the boiling point of the oxygen-containing compounds is ≤90℃. The aromatics can form a minimum azeotrope with the oxygen-containing compounds, and the content of aromatics in the liquid-phase composite solvent is 10% to 30%.

4. The low-temperature regeneration method for diesel adsorbent according to claim 1, characterized in that: In step S3, nitrogen is used to purge the bed at a temperature of 40°C to 80°C, and the nitrogen purge space velocity is 100 h⁻¹. -1 ~500h -1 The N2 purging pressure is 0.1 MPa to 0.3 MPa, and the purging time is 30 min to 150 min; preferably, the nitrogen cryogenic purging space velocity is 150 h⁻¹. -1 ~350h -1 The N2 purging pressure is 0.1MPa to 0.2MPa, and the purging time is 40min to 80min.

5. The low-temperature regeneration method for diesel adsorbent according to claim 1, characterized in that: In step S4, the bed is purged with nitrogen at a temperature of 100℃~160℃, and the nitrogen purge space velocity is 100 h⁻¹. -1 ~500h -1 The nitrogen purging pressure is 0.1 MPa to 0.3 MPa, and the purging time is 30 min to 150 min; preferably, the nitrogen high-temperature purging space velocity is 300 h⁻¹. -1 ~450h -1 The nitrogen purging pressure is 0.15MPa to 0.25MPa, and the purging time is 50min to 120min.

6. The low-temperature regeneration method for diesel adsorbent according to claim 1, characterized in that: In step S5, nitrogen is used to purge the bed at a temperature of 40°C to 80°C, and the nitrogen purge space velocity is 100 h⁻¹. -1 ~500h -1 The N2 purging pressure is 0.1 MPa to 0.3 MPa, and the purging time is 30 min to 150 min; preferably, the nitrogen cryogenic purging space velocity is 150 h⁻¹. -1 ~350h -1 The N2 purging pressure is 0.1MPa to 0.2MPa, and the purging time is 40 to 80 minutes.

7. The low-temperature regeneration method for diesel adsorbent according to claim 1, characterized in that: The diesel adsorbent is any one or a combination of several of molecular sieves, silica gel, alumina, or amorphous aluminum silicate; the diesel feedstock treated by the diesel adsorbent has a distillation range of 150℃ to 365℃.

8. The low-temperature regeneration method for diesel adsorbent according to claim 1, characterized in that: The process also includes step S6, in which the composite solvent containing diesel feedstock is recovered and reused through distillation.

9. [Amended according to Rule 26 07.04.2025] The low-temperature regeneration method for diesel adsorbent according to claim 8 is characterized in that: In step S6, the distillation column theoretically has 30-50 stages, a reflux ratio of 0.3-1.2, a solvent mass loss of ≤0.1%, and a recovered solvent purity of ≥95%.

10. The low-temperature regeneration method for diesel adsorbent according to claim 1, characterized in that: The low-temperature regeneration method is applicable to the regeneration of diesel adsorbents in any of the following types: fixed bed, moving bed, or simulated moving bed.

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