A continuous regeneration process for a continuous reforming catalyst

Abstract

The present application belongs to the technical field of petroleum refining, and is especially a continuous regeneration method of continuous reforming catalyst, comprising the following steps: S1: adding the catalyst to be regenerated into the catalyst bed formed by the inner net and the outer net in the first coking zone of the regenerator for coking; S2: the gas generated during coking in the first coking zone is discharged to the second line pipe through the first inner screen gas collecting pipe, then treated by the first air cooler, and the coking tail gas is discharged to the air purification system after being cooled by the first coking zone tail gas air cooler. The present application realizes the washing of HCl and CO2 in the regenerated gas in the production process by setting the high-efficiency alkali washing tower, thereby preventing the corrosion of HCl and CO2 in the regenerated gas to the equipment; the two-stage coking mode of the first coking gas and the second coking zone gas is set, i.e. the two-stage coking is carried out separately, thereby preventing the high-water and high-HCl environment in the first stage from being brought into the second coking, so as to easily control the temperature, completely coke, and fully recover the catalyst activity.

Description

[0001] This invention relates to the field of petroleum refining technology, specifically to a continuous regeneration method for a continuous reforming catalyst. Background Technology

[0002] 1. Continuous catalytic reforming of naphtha is one of the main processes in petroleum refining. It involves converting naphtha into a reformate rich in aromatics under specific temperature, pressure, hydrogen, and catalyst conditions, while also producing hydrogen as a byproduct. The reformate can be used as a component of high-octane gasoline, directly as a blending agent for automotive gasoline, or it can be used to produce chemical products such as benzene, toluene, and xylene through an aromatics extraction unit. The byproduct hydrogen is one of the main sources of hydrogen for refinery hydrotreating units. The core of the continuous catalytic reforming process is catalyst regeneration technology, which includes four steps: catalyst coking, chlorination, roasting, and reduction.

[0003] 2. The catalyst coking process is a process in which oxygen-containing circulating nitrogen gas burns off the carbon deposits on the catalyst. In this process, carbon dioxide and water are produced, and a large amount of heat is released.

[0004] 3. In the regeneration process of existing naphtha continuous catalytic reforming catalysts, the high water content and insufficient circulation volume in the circulating nitrogen during coking cause significant damage to the catalyst performance, thus shortening the catalyst's service life and affecting the activity of the regenerated catalyst, which in turn affects the yield and quality of the unit's products. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a continuous regeneration method for continuous reforming catalysts, solving the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a continuous regeneration method for a continuous reforming catalyst, wherein the reactor uses spherical particle catalyst, and during the reaction process, the coke-containing catalyst is continuously removed from the reactor, and the regeneration process such as coking, chlorination oxidation, and roasting is completed in the regenerator. The regenerated catalyst is fed into the upper hopper of the reactor through the regenerator elevator, and then enters the reactor system to continue participating in the catalytic reforming reaction; the upper part of the regenerator is a first coking zone and a second coking zone, and the lower part is a chlorination oxidation zone and a roasting zone.

[0007] In a preferred embodiment of the present invention, the catalyst undergoes two-stage coking in a regenerator. The primary coking process (approximately 95% or more) is completed in the first stage. The second stage, a supplementary coking zone, uses a higher oxygen content, higher coking temperature, and a drier coking environment to burn off residual or difficult-to-burn carbon deposits on the catalyst. The circulating nitrogen from the first stage coking zone is circulated separately and not introduced into the second stage to prevent the large amount of water vapor generated during coking from impacting the catalyst in the second stage and affecting the mechanical strength of the catalyst support. A small amount of nitrogen is discharged from the outlet of the first stage coking zone. The gas is sent to the top of the coking zone bed to preheat the catalyst. Most of the circulating nitrogen is heated to 460-470°C by an electric heater. It first preheats the catalyst entering the top of the regenerator, then enters the outer mesh of the first stage of the regenerator, and then passes radially through the catalyst layer to burn off the carbon deposits. The upper regeneration gas is collected at the top and discharged from the top of the regenerator. After being cooled by the upper regeneration air cooler, the temperature of the upper regeneration gas drops to 460°C. It is mixed with the supplementary air that has been dried by the air dryer, and after being pressurized by the upper regeneration hot air blower and temperature controlled by the electric heater, it is sent back to the regeneration tower for coking cycle.

[0008] As a preferred embodiment of the present invention, the circulating nitrogen gas at the outlet of the second-stage coking zone is heated to 480-490°C by an electric heater and then sent to the outer mesh of the second stage of the regenerator. It then passes radially through the catalyst layer to burn off residual carbon deposits or carbon deposits that are difficult to burn off on the catalyst. The lower regeneration gas is collected from the collection pipe in the middle of the regeneration tower and discharged from the outlet of the regenerator. After being cooled by the lower regeneration heat exchanger, the temperature drops to 550°C. It is then mixed with the supplementary air that has been dried by the air dryer and enters the alkaline washing and purification process.

[0009] As a preferred embodiment of the present invention, the lower regenerated gas is extracted from the regenerator side outlet, cooled by heat exchanger, and then mixed with alkaline solution supplied by regenerated alkaline washing circulation pump, so that the chlorine and carbon dioxide in the gas are neutralized by the alkali. Then, it is further cooled by regenerated gas circulation cooler, and finally enters regenerated gas alkaline washing tower for further water washing. After alkaline washing and water washing, the gas is cooled, regenerated circulator, dried by water absorption in dryer, regenerated circulating gas filter (to filter dust), and replenished with air to adjust the oxygen content before starting the next cycle.

[0010] In a preferred embodiment of the present invention, the roasting medium in the roasting and chlorination gas circulation loop is a mixture of secondary regeneration gas and purified compressed air. The purified compressed air is pressurized by an air compressor, dried by an air drying system, and then mixed with the regeneration gas from the outlet of the circulating fan in the secondary coking zone. Air is added to the regeneration gas to ensure that the oxygen content in the roasting and oxychlorination gas is 3% to 6% (mol). After heat exchange in the roasting heat exchanger and heating by the roasting electric heater, the gas enters the roasting section and passes through the catalyst bed in reverse to roast and dry the catalyst. It then enters the chlorination zone through small holes in the partition between the chlorination zone and the roasting zone, where it mixes with the organic chlorides that have been pressurized by the chlorination injection pump and vaporized by the chlorination heater to oxidize the catalyst. The gas extracted from the chlorination section is cooled by the roasting feed heat exchanger and then mixed with the secondary regeneration circulation gas, entering the secondary regeneration circulation gas loop as the source of oxygen consumed in the secondary regeneration coking.

[0011] As a preferred technical solution of the present invention, the function of the regenerated gas scrubbing tower is to wash away HCl and CO2 in the regenerated gas to prevent corrosion of the equipment. The regenerated gas scrubbing tower is divided into two parts: alkaline scrubbing and water scrubbing. First, the regenerated gas is mixed with a 3% (heavy) alkaline solution to wash away HCl and CO2. Then, water and gas are mixed again in the tower to wash away the residual alkali in the gas. The washed gas is then dried by a regenerated dryer to remove the saturated water in the gas. The dried gas is then returned to the regenerated gas recirculation compressor for reuse.

[0012] Compared with the prior art, the present invention has the following beneficial effects:

[0013] 1. This invention, by setting up a high-efficiency alkaline washing tower, achieves the removal of HCl and CO2 from the regenerated gas during the production process, thereby preventing the corrosion of the equipment by HCl and CO2 in the regenerated gas.

[0014] 2. This invention sets up a two-stage coking mode with a first-stage coking gas and a second-stage coking zone gas, that is, the two stages of gas are coked separately, which prevents the high water and high HCl environment of the first stage from being introduced into the second stage of coking, thereby achieving the purpose of easy temperature control, complete coking, and full recovery of catalyst activity.

[0015] 3. In this invention, setting up a roasting zone can increase the oxygen content, which is beneficial to the dispersion of platinum and avoids greater damage to the catalyst. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the present invention;

[0017] Figure 2 This is a schematic diagram of the air purification system structure of the present invention;

[0018] Figure 3 This is a schematic diagram of the air supply system structure of the present invention.

[0019] In the diagram: 1. Pipeline No. 1; 2. Feeding leg No. 1; 3. Catalyst bed formed by the inner and outer screens of the first-stage coking zone; 4. Feeding leg No. 2; 5. Catalyst bed formed by the inner and outer screens of the second-stage coking zone; 6. Upper space enclosed by the outer screen of the first-stage coking zone and the inner wall of the regenerator; 7. Upper space enclosed by the outer screen of the second-stage coking zone and the inner screen of the regenerator; 8. Gas collection pipe of the first-stage inner screen; 9. Gas collection pipe of the second-stage inner screen; 10. Feeding leg No. 3; 11. Oxychlorination zone; 12. Feeding leg No. 4; 13. 14. Calcination Zone; 15. Pipeline 2; 16. First Stage Coke Oven Air Cooler; 17. Pipeline 3; 18. Regeneration Hot Air Fan; 19. First Stage Electric Heater; 20. Pipeline 5; 21. Pipeline 6; 22. Pipeline 7; 23. Lower Regeneration Heat Exchanger; 24. Pipeline 8; 25. Alkali Mixer; 26. Alkali Washing Cooler; 27. Pipeline 9; 28. High-Efficiency Alkali Washing Tower; 29. ​​Demineralized Water Inlet; 30. Pipeline 10; 31. Alkali Washing Aftercooler; 32. Pipeline 10 Pipeline 1; 33. Drying Skid; 34. Pipeline 12; 35. Filter Skid; 36. Pipeline 13; 37. Pipeline 14; 38. Circulating Compressor Inlet Buffer Tank; 39. Circulating Compressor; 40. Pipeline 15; 41A. Pipeline 31; 41B. Pipeline 32; 42. Second-Stage Electric Heater; 43. Pipeline 33; 44. Pipeline 16; 45. Pipeline 17; 46. Alkali Circulating Pump; 47. Pipeline 18; 48. Pipeline 19; 49. 50. Air compressor; 51. Air pressure stabilizing tank; 52. Pipeline 21; 53. Air dryer; 54. Pipeline 22; 55. Pipeline 23; 56. Pipeline 24; 57. Calcination feed heat exchanger; 58. Pipeline 25; 59. Calcination electric heater; 60. Pipeline 26; 61. Pipeline 27; 62. Pipeline 28; 63. Pipeline 29; 64. Chlorine injection pump; 65. Chlorine injection heater; 66. Pipeline 30. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0021] Example

[0022] Please see Figure 1-3This invention provides the following technical solution: The regenerator consists of, from top to bottom, a first-stage coking zone, a second-stage coking zone, an oxychlorination zone 11, and a roasting zone 13. The catalyst to be recycled from the moving bed reactor enters the regenerator and, along multiple uniformly annular feed legs, descends into the first-stage coking zone by gravity. Within the annular space of the coking zone, it slowly moves downwards by gravity. Before entering the second-stage coking zone, approximately 95% of the carbon deposits are burned off. In the second-stage coking zone, with its higher oxygen content, higher coking temperature, and drier coking environment, residual carbon deposits or difficult-to-burn carbon deposits on the catalyst are burned off. After completing the two-stage coking process, the catalyst, under the influence of gravity, enters the oxychlorination zone 11 and undergoes counter-current contact with a gas containing chlorine and oxygen to redistribute the metal components and ensure good catalyst performance. Then, it enters the roasting zone 13 to remove moisture from the catalyst before exiting the regenerator.

[0023] The catalyst awaiting combustion enters through pipeline 1 (number 1) and then through multiple feed legs 2 (number 1), before entering the catalyst bed 3 formed by the inner and outer coking meshes in the coking zone for coking. After completing its primary coking task, the catalyst enters through feed legs 4 (number 2) and then through the catalyst bed 5 formed by the inner and outer meshes in the second coking zone. The coked catalyst then enters the oxychlorination zone 11 (number 3) through feed legs 10. After replenishment of chlorides and metal redispersibility, the catalyst enters the roasting zone 13 (number 4) through feed legs 12. After removing moisture from the catalyst, it is led out of the regenerator through pipeline 66 (number 30).

[0024] A small amount of gas drawn from the outlet of the first-stage regeneration hot air blower 18 is used via pipeline 20 to preheat the catalyst at the top of the catalyst bed 3 formed by the inner and outer meshes of the first-stage coking zone. Most of the gas from the outlet of the regeneration hot air blower 18 is conditioned to approximately 470°C by the first-stage electric heater 19, and then enters the regenerator via pipeline 21. Passing through the upper space 6 formed by the outer screen of the first-stage coking zone and the inner wall of the regenerator, the coking gas is evenly distributed and passes through the catalyst bed 3 formed by the inner and outer meshes of the first-stage coking zone, entering the gas collection pipe 8 of the first-stage inner screen. The coking tail gas then enters the first-stage coking tail gas air cooler 15 via pipeline 14, where the temperature is regulated and controlled at approximately 460°C. To maintain a constant pressure at the top of the regenerator, pipeline 17 is installed to the gas alkaline washing and purification system for treatment before venting. Most of the first-stage coking tail gas and dried air are mixed via pipeline 55, then pressurized by the regeneration hot air blower 18 and circulated back to the first-stage coking zone to complete the first-stage coking gas cycle. The air required for the regeneration of the coke is supplied by air compressor 49.

[0025] The coking gas from the second stage is heated by the second-stage electric heater 42 and then enters the upper space 7 formed by the outer screen of the second-stage coking zone and the inner wall of the regenerator via pipeline 33 (43). The gas is then evenly distributed through the catalyst bed 5 formed by the inner and outer screens of the second-stage coking zone and enters the gas collection pipe 9 of the inner screen. The coking tail gas enters the lower regeneration heat exchanger 23 via pipeline 7 (22) and exchanges heat with the low-temperature second-stage coking gas. It then enters the alkali mixer 25 via pipeline 8 (24), where it mixes with the alkali solution from the bottom of the high-efficiency alkali washing tower 28. After further cooling via the alkali washing cooler 26, it enters the high-efficiency alkali washing tower 28 via pipeline 9 (27). The high-efficiency alkali washing tower 28 is a composite tower, with the lower part performing gas alkali washing and the upper part performing water washing. To maintain the alkali concentration, pipeline 16 (44) is installed at the inlet of the alkali circulation pump 46. The mixed alkali solution is pressurized by the alkali circulation pump 46 and then circulated into the alkali mixer 25 via pipeline 18 (47). The demineralized water continuously enters the top of the alkaline washing tower through the demineralized water inlet 29 to complete the water washing process of the gas.

[0026] The coking gas from the second stage, after alkaline washing and water washing, enters the alkaline washing aftercooler 31 via pipeline 10 (30). After being cooled again, the gas enters the gas drying skid 33 via pipeline 11 (32). The drying skid 33 uses molecular sieve adsorbent to remove moisture from the second-stage coking gas through temperature-switching adsorption. Then, it is sent to the filter skid 35 via pipeline 12 (34) to remove any desiccant dust that may be carried away. The purified gas enters the inlet buffer tank 38 of the circulating compressor via pipeline 13 (36) for pressure stabilization. A portion of the coking tail gas is vented via pipeline 14 (37) to achieve system pressure balance and gas material balance. Most of the coking tail gas is pressurized by the circulating compressor 39 and enters the lower regeneration heat exchanger 23 via pipeline 15 (40) for heat exchange and preheating. Then, it is heated to 480-490℃ via pipeline 31 (41A) and the second-stage electric heater 42 before being sent to the external network of the second stage regenerator for continuous coking, completing the circulation of the second-stage coking gas. The oxygen for the second stage of burning is supplied by pipeline 62 of number 28.

[0027] Purified air from pipeline 48 (line 19) is compressed by air compressor 49 and then enters air pressure stabilizing tank 51 via pipeline 50 (line 20) for pressure stabilization. It is then sent to air dryer 53 via pipeline 52 for drying. Low dew point air is split into two streams via pipeline 54 (line 22). One stream, via pipeline 55 (line 23), provides oxygen for the first stage of coking. The other stream mixes with gas from the outlet of circulating compressor 39 via pipeline 41B (line 32) and enters roasting feed heat exchanger 57 for preheating before being sent to roasting electric heater 59 for heating to 540°C. It then enters regenerator roasting zone 13 via pipeline 60 (line 26). Roasting gas flows counter-currently from bottom to top through the catalyst bed, roasting and drying the catalyst. It then enters oxychlorination zone 11 through the small hole A of the chlorine injection heater on the partition between oxychlorination zone 11 and roasting zone 13, mixing with the organic chlorides that have been pressurized by chlorination injection pump 64 and vaporized by chlorination heater 65, thus regenerating the catalyst through chlorination oxidation. Gas extracted from oxychlorination zone 11 is cooled by roasting feed heat exchanger 57 via pipeline 27 61 and mixed with second-stage regeneration circulating gas via pipeline 28 62. This mixture then enters the second-stage regeneration circulating gas loop, serving as the source of oxygen for second-stage regeneration coking.

[0028] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for continuous regeneration of a continuous reforming catalyst, comprising a primary coking zone and a secondary coking zone, characterized in that: Includes the following steps: S1: Add the oxidizing agent into the catalyst bed formed by the inner and outer meshes of the coking zone inside the regenerator for coking; S2: The gas generated during coking in the coking zone is discharged to the No. 2 line pipe through the gas collection pipe with an inner screen. Then, it is processed by the air cooler. After being cooled by the exhaust gas air cooler of the coking zone, the coking exhaust gas is discharged to the air purification system. S3: The air supply system splits the air into two paths, one of which is delivered to the hot air blower and the other to the roasting zone; The air supply system also includes the following steps: A1: Purified compressed air enters the air compressor through pipeline number 19; A2: After being processed by the air compressor, the air is delivered to the air pressure stabilizing tank along pipeline number 20; A3: The air pressure stabilizing tank then delivers air to the air dryer through pipeline number 21; A4: The air dried by the air dryer is transported to the first coking zone and the roasting zone through pipeline No. 22; S4: The hot air blower heats the gas and then discharges it into the upper space enclosed by the screen outside the coking zone and the inner wall of the regenerator; S5: Under the action of gravity, the pre-generated agent enters the catalyst bed formed by the inner and outer nets of the second coking zone through the No. 2 feeding leg for secondary coking. S6: The coking exhaust gas generated during coking in the second-stage coking zone is discharged to the lower regeneration heat exchanger through pipeline No.

7. After being treated by the lower regeneration heat exchanger, the gas is discharged to the air purification system through pipeline No.

8. S7: The exhaust gas treated by the air purification system enters the second-stage electric heater through the lower regeneration heat exchanger and pipeline No.

31. The air heated by the second-stage electric heater then enters the upper space enclosed by the outer screen of the second-stage coking zone and the inner screen of the regenerator through pipeline No.

33. The air purification system also includes the following steps: B1: The coking exhaust gas is transported to the alkaline solution mixer via pipeline No. 8; B2: The coking exhaust gas is mixed with fresh alkali solution from the bottom of the high-efficiency alkali scrubbing tower in the alkali solution mixer, and then cooled by the alkali scrubbing cooler before entering the high-efficiency alkali scrubbing tower through pipeline No.

9. B4: The coking exhaust gas after alkaline washing is processed by the alkaline washing cooler and sent to the drying skid via pipeline No.

11. B5: The coke exhaust gas, after being dried by the drying skid, is sent to pipeline No. 15 after passing through pipeline No. 12, the filter skid, pipeline No. 13, the buffer tank at the inlet of the circulating compressor, and the compression of the circulating compressor. B6: Pipeline No. 15 divides the purified coking exhaust gas into two paths, one of which is sent to the second coking zone, and the other is sent to the roasting zone through Pipeline No.

32. S8: The catalyst enters the oxychlorination zone for oxidation under the action of gravity through the No. 3 feed leg; S9: The chlorination system injects tetrachloroethylene into the oxychlorination zone, where chlorination takes place; The chlorine injection system also includes the following steps: C1: Tetrachloroethylene is added to the chlorine injection pump through pipeline number 29; C2: The chlorine injection pump injects tetrachloroethylene into the chlorine injection heater for heating; C3: Tetrachloroethylene heated by the chlorination heater is finally injected into the oxychlorination zone; S10: The catalyst enters the roasting zone through the No. 4 feed leg under the action of gravity; S11: Finally, under the influence of gravity, the qualified catalyst is discharged through pipeline No. 30; Specifically, S3 involves the air dryer transporting the processed air to the hot air blower along pipelines 22 and 23, the air dryer then sending the processed air to the roasting feed heat exchanger along pipelines 22 and 24, and finally the air that has been finely processed by the roasting feed heat exchanger is heated again by the roasting electric heater and then sent into the roasting zone along pipeline 26. Specifically, S4 involves a hot air blower splitting the air delivered from the air dryer into two paths. One path is directly discharged into the upper space enclosed by the screen outside the coking zone and the inner wall of the regenerator. The other path is heated by an electric heater and then discharged through pipeline No. 6 into the upper space enclosed by the screen outside the coking zone and the inner wall of the regenerator.

2. The continuous regeneration method for a continuous reforming catalyst according to claim 1, characterized in that: Specifically, S2 involves injecting fresh alkali solution into pipeline 17 through pipeline 16, which then transports the fresh alkali solution to the alkali solution circulation pump. The alkali solution circulation pump then sends the fresh alkali solution to the alkali solution mixer through pipeline 18.

Images