Apparatus for recovering propylene product guard bed material during shutdown

Abstract

The utility model discloses a device of recovery propylene product guard bed material in shutdown process, including propylene product guard bed group, the top of propylene product guard bed group all is connected with the stamping unit, the bottom of propylene product guard bed group all is connected with recovery unit, and the inlet end and the outlet end of propylene product guard bed group are connected with pipeline, and the pipeline is provided with first valve and second valve. The utility model device can recover propylene product guard bed material when the olefin separation device stops, and avoids propylene material loss.

Description

Technical Field

[0001] This utility model belongs to the technical field of propylene product protective bed material recovery device, specifically relating to a device for recovering propylene product protective bed material during shutdown. Background Technology

[0002] The propylene product protection bed is part of the olefin separation unit, but currently there is no material recovery system for the propylene product protection bed. When the olefin separation unit is shut down for maintenance, the propylene product protection bed also needs to be shut down. This results in 30 m³ of propylene material in the propylene product protection bed and 30 m³ of propylene material in the propylene product protection bed buffer tank being discharged to the flare system for processing, causing a large loss of propylene material. Utility Model Content The purpose of this invention is to provide a device for recovering propylene product protective bed material during shutdown, thereby solving the problem that propylene product protective bed material cannot be recovered when the olefin separation unit is shut down.

[0003] The technical solution adopted by this utility model is a device for recovering propylene product protective bed material during shutdown, including a propylene product protective bed group. The top of the propylene product protective bed group is connected to the stamping unit, and the bottom of the propylene product protective bed group is connected to the recovery unit. A pipeline is connected between the inlet end and the outlet end of the propylene product protective bed group, and a first valve and a second valve are installed on the pipeline.

[0004] The features of this utility model also include: The propylene product protection bed assembly includes a first propylene product protection bed and a second propylene product protection bed. At the inlet end of the first propylene product protection bed, in the direction of propylene flow, inlet electric valves B and A are sequentially installed. At the inlet end of the second propylene product protection bed, in the direction of propylene flow, inlet electric valves C and D are sequentially installed. The ends of inlet electric valves B and C furthest from the protection bed are both connected to pipelines. At the outlet end of the first propylene product protection bed, outlet electric valves A and B are sequentially installed in the direction of propylene flow. At the outlet end of the second propylene product protection bed, in the direction of propylene flow, outlet electric valves D and C are sequentially installed. The ends of outlet electric valves B and C furthest from the protection bed are both connected to pipelines.

[0005] The stamping unit includes a main stamping pipeline with a pressure control valve. One end of the main stamping pipeline is connected to a pressure source, and the other end of the main stamping pipeline is connected to a first stamping branch pipeline and a second stamping branch pipeline. The first stamping branch pipeline is connected to the top of the first propylene product protective bed, and the second stamping branch pipeline is connected to the top of the second propylene product protective bed.

[0006] Pneumatic valves A and B are installed on the first stamping branch line, and pneumatic valves C and D are installed on the second stamping branch line.

[0007] The recovery unit includes a three-stage suction buffer tank for a propylene refrigeration compressor. The bottom of the three-stage suction buffer tank is sequentially connected to an eighth valve, a propylene discharge pump, and a ninth valve. The side wall of the three-stage suction buffer tank is connected to one end of the main recovery pipeline. The other end of the main recovery pipeline is connected to a first recovery branch pipeline and a second recovery branch pipeline. The main recovery pipeline is sequentially equipped with a third valve, a fourth valve, a seventh valve, and a sixth valve according to the propylene flow direction. The first recovery branch pipeline is connected to the bottom of the first propylene product protection bed, and the second recovery branch pipeline is connected to the bottom of the second propylene product protection bed. The ends of the first and second recovery branch pipelines closest to the main recovery pipeline are connected.

[0008] The first recovery branch line is equipped with a fifth valve, and the second recovery branch line is equipped with a tenth valve.

[0009] It also includes a propylene product protective bed buffer tank, the bottom of which is connected to one end of the third recovery branch line, the other end of which is connected to the main recovery line, and the third recovery branch line is connected to the ends of the first and second recovery branch lines near the main recovery line. The top of the propylene product protective bed buffer tank is connected to one end of the third stamping branch line, and the other end of the third stamping branch line is connected to the main stamping line.

[0010] The eleventh valve is installed on the third recovery branch line, and pneumatic valves E and F are installed on the third stamping branch line.

[0011] The beneficial effects of this utility model are: (1) The device for recovering propylene product protective bed material during shutdown of this utility model can recover propylene material in the first propylene product protective bed, the second propylene product protective bed, and the propylene product protective bed buffer tank by setting up a recovery unit; (2) The device for recovering propylene product protective bed material during the shutdown process of this utility model can cut out the propylene product protective bed or propylene product protective bed buffer tank in advance for shutdown disposal by setting up pipelines, first valve and second valve; (3) The device for recovering propylene product protective bed material during the shutdown process of this utility model can pressurize the first propylene product protective bed, the second propylene product protective bed, and the propylene product protective bed buffer tank by setting a stamping unit and maintain stable pressure, thereby completely removing and recovering the propylene material in the first propylene product protective bed, the second propylene product protective bed, and the propylene product protective bed buffer tank. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the device for recovering propylene products and protecting bed materials during shutdown.

[0013] In the diagram, 1. First valve, 2. Second valve, 3. First propylene product protection bed, 4. Outlet electric valve A, 5. Outlet electric valve B, 6. Inlet electric valve A, 7. Inlet electric valve B, 8. Fifth valve, 9. Third valve, 10. Fourth valve, 11. Propylene refrigeration compressor three-stage suction buffer tank, 12. Sixth valve, 13. Seventh valve, 14. Eighth valve, 15. Propylene discharge pump, 16. Ninth valve, 17. Pneumatic valve A, 18. Pneumatic valve B, 19. Pressure control valve, 20. Outlet electric valve C, 21. Outlet electric valve D, 22. Inlet electric valve 23. Electric inlet valve D, 24. Second propylene product protection bed, 25. Tenth valve, 26. Pneumatic valve C, 27. Pneumatic valve D, 28. Eleventh valve, 29. Propylene product protection bed buffer tank, 30. Pneumatic valve E, 31. Pneumatic valve F, 32. Twelfth valve, 33. Thirteenth valve, 34. Main stamping line, 35. First stamping branch line, 36. Second stamping branch line, 37. Third stamping branch line, 38. Main recovery line, 39. First recovery branch line, 40. Second recovery branch line, 41. Third recovery branch line, 42. Pipeline. Detailed Implementation

[0014] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0015] Example 1 This utility model relates to a device for recovering propylene products and protecting bed materials during shutdown, the structure of which is as follows: Figure 1 As shown, the system includes propylene product protection beds. The top of each propylene product protection bed is connected to a stamping unit. The end of the stamping unit furthest from the propylene product protection bed is connected to a pressure source, which provides pressure. The stamping unit is used to stamp the propylene product protection bed to stabilize the pressure within the bed, ensuring complete material discharge. The bottom of each propylene product protection bed is connected to a recovery unit. The end of the recovery unit furthest from the propylene product protection bed is connected to the tank area. The recovery unit is used to recover the discharged propylene material from the propylene product protection bed for recycling. A pipeline 42 connects the inlet and outlet of the propylene product protection bed. A first valve 1 and a second valve 2 are installed on the pipeline 42. The inlet of the propylene product protection bed is connected to the propylene distillation system, and the outlet is connected to the tank area. One end of the pipeline 42 is located between the inlet and the propylene distillation system, and the other end is located between the outlet and the tank area. Multiple propylene product protection beds are installed within the propylene product protection bed system; some are operational, and some are on standby. The standby propylene product protection beds are in a closed state. The operation process of the device for recovering propylene product protective bed material during shutdown in this embodiment is as follows: Opening the first valve 1 and the second valve 2 opens pipeline 42, stopping the feeding and discharging of the propylene product protective bed in the propylene product protective bed group. This effectively shuts down the operating propylene product protective bed. At this time, the propylene product from the propylene distillation system directly enters the tank area for storage through pipeline 42, no longer entering the propylene product protective bed group. The recovery unit is opened to recover the propylene material, and then the stamping unit is opened to pressurize the operating propylene product protective bed, maintaining stable pressure within the operating propylene product protective bed. Under pressure, the propylene material in the operating propylene product protective bed enters the recovery unit and is transported to the tank area device, thus realizing the recovery of propylene material. The material return process for other propylene product protective beds is the same as the above-described material return process for the propylene product protective bed.

[0016] Example 2 Based on Example 1, the propylene product protection bed group includes two propylene product protection beds: a first propylene product protection bed 3 and a second propylene product protection bed 24. The inlet end of the first propylene product protection bed 3 is sequentially equipped with inlet electric valves B7 and A6 according to the propylene flow direction, and the inlet end is located at the bottom of the first propylene product protection bed 3. The inlet end of the second propylene product protection bed 24 is sequentially equipped with inlet electric valves C22 and D23 according to the propylene flow direction, and the inlet end is located at the bottom of the second propylene product protection bed 24. The ends of inlet electric valves B7 and C22 furthest from the protection bed are both connected to one end of pipeline 42, and the ends of inlet electric valves B7 and C22 furthest from the protection bed are both connected to the propylene distillation system. One end of pipeline 42 is located between the propylene distillation system and the connection points of inlet electric valves C22 and B7. The propylene in the first propylene product protection bed 3 and the second propylene product protection bed 24... All propylene materials are transported through the propylene distillation system. The outlet of the first propylene product protection bed 3 is sequentially equipped with outlet electric valves A4 and B5 according to the propylene flow direction, located at the top of the first propylene product protection bed 3. The outlet of the second propylene product protection bed 24 is sequentially equipped with outlet electric valves D21 and C20 according to the propylene flow direction, located at the top of the second propylene product protection bed 24. The ends of outlet electric valves B5 and C20 furthest from the protection bed are connected to the other end of pipeline 42. The ends of outlet electric valves B5 and C20 furthest from the protection bed are also connected to the tank area. The other end of pipeline 42 is located between the tank area and the connection point of outlet electric valves C20 and B5. The propylene product processed by the first propylene product protection bed 3 and the second propylene product protection bed 24 enters the tank area for storage. The first propylene product protection bed 3 and the second propylene product protection bed 24 are connected in parallel, one in operation and one on standby, with the bed regenerated every 15 days.

[0017] The operation process of the device for recovering propylene product protective bed material during shutdown in this embodiment is as follows: Taking the first propylene product protective bed 3 as running and the second propylene product protective bed 24 as standby (outlet electric valve D21, outlet electric valve C20, inlet electric valve C22, and inlet electric valve D23 are all closed) as an example, opening the first valve 1 and the second valve 2 makes pipeline 42 a passage. Closing the outlet electric valve A4, outlet electric valve B5, inlet electric valve A6, and electric valve B7, thereby cutting off the first propylene product protective bed 3 in advance for shutdown. At this time, the propylene product from the propylene distillation system directly enters the tank through pipeline 42. The propylene material is stored in the storage area and no longer enters the first propylene product protection bed 3. Then, the recovery unit is activated to recover and transport the propylene material in the first propylene product protection bed 3 to the tank area. Then, the stamping unit is activated to press into the first propylene product protection bed 3 to maintain stable pressure. The propylene material in the first propylene product protection bed 3 is slowly withdrawn into the recovery unit. Finally, the propylene material is recovered to the tank area through the recovery unit. When the second propylene product protection bed 24 is running and the first propylene product protection bed 3 is in standby mode, the material withdrawal process of the second propylene product protection bed 24 is the same as the material withdrawal process when the first propylene product protection bed 3 is running.

[0018] Example 3 Based on Embodiment 2, the stamping unit includes a main stamping pipeline 34, on which a pressure control valve 19 is installed. One end of the main stamping pipeline 34 is connected to a pressure source, which can be provided by a propylene distillation column or another connected pressure source. The other end of the main stamping pipeline 34 is connected to a first stamping branch pipeline 35 and a second stamping branch pipeline 36, respectively. The first stamping branch line 35 is connected to the top of the first propylene product protective bed 3, and the second stamping branch line 36 is connected to the top of the second propylene product protective bed 24. The first stamping branch line 35 is equipped with pneumatic valves A17 and B18, and the second stamping branch line 36 is equipped with pneumatic valves C26 and D27. Opening pneumatic valves A17, B18, and pressure control valve 19 can pressurize the first propylene product protective bed 3 and maintain the pressure inside the first propylene product protective bed 3. Opening pneumatic valves C26, D27, and pressure control valve 19 can pressurize the second propylene product protective bed 24 and maintain the pressure inside the second propylene product protective bed 24.

[0019] The operation process of the device for recovering propylene product protective bed material during shutdown in this embodiment is as follows: Taking the first propylene product protective bed 3 as running and the second propylene product protective bed 24 as standby (outlet electric valve D21, outlet electric valve C20, inlet electric valve C22, inlet electric valve D23, pneumatic valve C26, and pneumatic valve D27 are all in the closed state) as an example, opening the first valve 1 and the second valve 2 makes pipeline 42 a passage. Closing the outlet electric valve A4, outlet electric valve B5, inlet electric valve A6, and electric valve B7, thereby cutting off the first propylene product protective bed 3 in advance for shutdown. At this time, the propylene product from the propylene distillation system directly enters the tank area through pipeline 42. The propylene material is stored separately and no longer enters the first propylene product protection bed 3. Then, the recovery unit is activated to recover and transport the propylene material in the first propylene product protection bed 3 to the tank area. Then, pneumatic valves A17, B18, and pressure control valve 19 are opened to pressurize the first propylene product protection bed 3 to maintain stable pressure. The propylene material in the first propylene product protection bed 3 is slowly withdrawn into the recovery unit, and finally, the propylene material is recovered to the tank area through the recovery unit. When the second propylene product protection bed 24 is running and the first propylene product protection bed 3 is in standby mode, the material withdrawal process of the second propylene product protection bed 24 is the same as the material withdrawal process when the first propylene product protection bed 3 is running.

[0020] Example 4 Based on Example 3, the recovery unit includes a three-stage suction buffer tank 11 for the propylene refrigeration compressor. The bottom of the three-stage suction buffer tank 11 is sequentially connected to an eighth valve 14, a propylene discharge pump 15, a ninth valve 16, and a tank area. The side wall of the three-stage suction buffer tank 11 is connected to one end of the main recovery pipeline 38. The other end of the main recovery pipeline 38 is connected to a first recovery branch pipeline 39 and a second recovery branch pipeline 40. A third valve 9, a fourth valve 10, and a seventh valve 13 are sequentially installed on the main recovery pipeline 38 according to the propylene flow direction. The sixth valve 12 connects the first recovery branch line 39 to the bottom of the first propylene product protection bed 3, and the second recovery branch line 40 connects to the bottom of the second propylene product protection bed 24. The ends of the first recovery branch line 39 and the second recovery branch line 40 near the main recovery line 38 are connected, thereby enabling the mutual liquid transfer between the first propylene product protection bed 3 and the second propylene product protection bed 24. The first recovery branch line 39 is equipped with a fifth valve 8, and the second recovery branch line 40 is equipped with a tenth valve 25. When both the fifth valve 8 and the tenth valve 25 are open, mutual liquid transfer can be performed.

[0021] The operation process of the device for recovering propylene product protective bed material during shutdown in this embodiment is as follows: Taking the first propylene product protective bed 3 as running and the second propylene product protective bed 24 as standby (outlet electric valve D21, outlet electric valve C20, inlet electric valve C22, inlet electric valve D23, pneumatic valve C26, pneumatic valve D27, and tenth valve 25 are all closed) as an example, the first valve 1 and the second valve 2 are opened, so pipeline 42 is open. The outlet electric valve A4, outlet electric valve B5, inlet electric valve A6, and electric valve B7 are closed, thereby cutting off the first propylene product protective bed 3 in advance for shutdown. At this time, the propylene product from the propylene distillation system directly enters the tank area for storage through pipeline 42 and no longer enters the first propylene product protective bed 3. Then, the fifth valve 8 and the third valve are opened. Valve 9, valve 10, valve 13, and valve 12 are used to return the propylene material in the first propylene product protection bed 3 to the third-stage suction buffer tank 11 of the propylene refrigeration compressor. Then, pneumatic valves A17, B18, and pressure control valve 19 are opened to pressurize the first propylene product protection bed 3, maintaining stable pressure within the bed. The propylene material in the first propylene product protection bed 3 is then slowly returned to the third-stage suction buffer tank 11 of the propylene refrigeration compressor. Next, valves 14 and 16 are opened, and the propylene discharge pump 15 is started to return the propylene material to the tank area for storage. When the second propylene product protection bed 24 is running and the first propylene product protection bed 3 is on standby, the discharge process of the second propylene product protection bed 24 is the same as that of the first propylene product protection bed 3 during operation.

[0022] Example 5 Based on Example 4, the system also includes a propylene product protective bed buffer tank 29. The bottom of the propylene product protective bed buffer tank 29 is connected to one end of the third recovery branch line 41, and the other end of the third recovery branch line 41 is connected to the main recovery line 38. The third recovery branch line 41 is also connected to the ends of the first recovery branch line 39 and the second recovery branch line 40 near the main recovery line 38, thereby achieving communication between the first propylene product protective bed 3, the second propylene product protective bed 24, and the propylene product protective bed buffer tank 29. The liquids are mutually transferred. The top of the propylene product protective bed buffer tank 29 is connected to one end of the third pressurization branch line 37, and the other end of the third pressurization branch line 37 is connected to the main pressurization line 34. An eleventh valve 28 is installed on the third recovery branch line 41, and pneumatic valves E30 and F31 are installed on the third pressurization branch line 37. When pneumatic valves E30, F31, and pressure control valve 19 are opened, the propylene product protective bed buffer tank 29 is pressurized to maintain the pressure stability inside the propylene product protective bed buffer tank 29.

[0023] The operation process of the device for recovering propylene product protective bed material during shutdown in this embodiment is as follows: Taking the first propylene product protective bed 3 as running and the second propylene product protective bed 24 as standby (outlet electric valve D21, outlet electric valve C20, inlet electric valve C22, and inlet electric valve D23 are all closed) as an example, the first valve 1 and the second valve 2 are opened, so pipeline 42 is open. The outlet electric valve A4, outlet electric valve B5, inlet electric valve A6, electric valve B7, pneumatic valve E30, pneumatic valve F31, and eleventh valve 28 are closed, thereby cutting off the first propylene product protective bed 3 in advance for shutdown. At this time, the propylene product from the propylene distillation system directly enters the tank area for storage through pipeline 42 and no longer enters the first propylene product protective bed 3. Then the fifth valve 8 and the third valve 28 are opened. Valves 9, 10, 13, and 12 are used to return the propylene material in the first propylene product protection bed 3 to the third-stage suction buffer tank 11 of the propylene refrigeration compressor. Then, pneumatic valves A17, B18, and pressure control valve 19 are opened to pressurize the first propylene product protection bed 3, maintaining stable pressure within the bed. The propylene material in the first propylene product protection bed 3 is then slowly returned to the third-stage suction buffer tank 11 of the propylene refrigeration compressor. Next, valves 14 and 16 are opened to start the propylene return pump 15, returning the propylene material to the tank area for storage. When the second propylene product protection bed 24 is running and the first propylene product protection bed 3 is on standby, the return process of the second propylene product protection bed 24 is the same as the return process when the first propylene product protection bed 3 is running.

[0024] When the propylene product protective bed buffer tank 29 is unloaded, the first valve 1 and the second valve 2 are opened, making pipeline 42 unobstructed. Then, the following valves are closed: outlet electric valve A4, outlet electric valve B5, inlet electric valve A6, electric valve B7, pneumatic valve A17, pneumatic valve B18, fifth valve 8, outlet electric valve C20, outlet electric valve D21, inlet electric valve C22, inlet electric valve D23, pneumatic valve C26, pneumatic valve D27, and tenth valve 25. This allows the propylene product protective bed buffer tank 29 to be shut down prematurely. At this time, the propylene product from the propylene distillation system directly enters the tank area for storage through pipeline 42 and no longer enters the propylene product protective bed. Buffer tank 29, then open eleventh valve 28, third valve 9, fourth valve 10, seventh valve 13, and sixth valve 12 to return the propylene material in the first propylene product protection bed 3 to the propylene refrigeration compressor third-stage suction buffer tank 11. Then open pneumatic valve E30, pneumatic valve F31, and pressure control valve 19 to pressurize the propylene product protection bed buffer tank 29, maintaining stable pressure inside the propylene product protection bed buffer tank 29. Slowly return the propylene material in the propylene product protection bed buffer tank 29 to the propylene refrigeration compressor third-stage suction buffer tank 11. Then open eighth valve 14 and ninth valve 16 to start the propylene discharge pump 15 to return the propylene material to the tank area for storage.

[0025] Example 6 Based on Example 5, the end of the ninth valve 16 away from the propylene discharge pump 15 is provided with the twelfth valve 32 and the thirteenth valve 33 in sequence according to the propylene material flow direction.

Claims

1. A device for recovering propylene product protective bed material during shutdown, characterized in that, The propylene product protection bed is connected to the stamping unit at the top and to the recycling unit at the bottom. A pipeline (42) is connected between the inlet and outlet of the propylene product protection bed. A first valve (1) and a second valve (2) are installed on the pipeline (42).

2. The apparatus for recovering propylene product protective bed material during shutdown as described in claim 1, characterized in that, The propylene product protection bed group includes a first propylene product protection bed (3) and a second propylene product protection bed (24). The inlet end of the first propylene product protection bed (3) is provided with an inlet electric valve B (7) and an inlet electric valve A (6) in sequence according to the propylene flow direction. The inlet end of the second propylene product protection bed (24) is provided with an inlet electric valve C (22) and an inlet electric valve D (23) in sequence according to the propylene flow direction. The ends of the inlet electric valves B (7) and C (22) away from the protection bed are connected to one end of the pipeline (42). The outlet end of the first propylene product protection bed (3) is provided with an outlet electric valve A (4) and an outlet electric valve B (5) in sequence according to the propylene flow direction. The outlet end of the second propylene product protection bed (24) is provided with an outlet electric valve D (21) and an outlet electric valve C (20) in sequence according to the propylene flow direction. The ends of the outlet electric valves B (5) and C (20) away from the protection bed are connected to the other end of the pipeline (42).

3. The apparatus for recovering propylene product protective bed material during shutdown as described in claim 2, characterized in that, The stamping unit includes a main stamping pipeline (34), on which a pressure control valve (19) is provided. One end of the main stamping pipeline (34) is connected to a pressure source, and the other end of the main stamping pipeline (34) is connected to a first stamping branch pipeline (35) and a second stamping branch pipeline (36). The first stamping branch pipeline (35) is connected to the top of the first propylene product protection bed (3), and the second stamping branch pipeline (36) is connected to the top of the second propylene product protection bed (24).

4. The apparatus for recovering propylene product protective bed material during shutdown as described in claim 3, characterized in that, The first stamping branch line (35) is equipped with pneumatic valve A (17) and pneumatic valve B (18), and the second stamping branch line (36) is equipped with pneumatic valve C (26) and pneumatic valve D (27).

5. The apparatus for recovering propylene product protective bed material during shutdown as described in claim 3, characterized in that, The recycling unit includes a three-stage suction buffer tank (11) for a propylene refrigeration compressor. The bottom of the three-stage suction buffer tank (11) for a propylene refrigeration compressor is connected in sequence to an eighth valve (14), a propylene discharge pump (15), and a ninth valve (16). The side wall of the three-stage suction buffer tank (11) for a propylene refrigeration compressor is connected to one end of the main recycling pipeline (38). The other end of the main recycling pipeline (38) is connected to a first recycling branch pipeline (39) and a second recycling branch pipeline (40). The main recycling pipeline (38) is provided with a third valve (9), a fourth valve (10), a seventh valve (13), and a sixth valve (12) in sequence according to the propylene flow direction. The first recycling branch pipeline (39) is connected to the bottom of the first propylene product protection bed (3), and the second recycling branch pipeline (40) is connected to the bottom of the second propylene product protection bed (24). The ends of the first recycling branch pipeline (39) and the second recycling branch pipeline (40) near the main recycling pipeline (38) are connected.

6. The apparatus for recovering propylene product protective bed material during shutdown as described in claim 5, characterized in that, The first recovery branch line (39) is equipped with a fifth valve (8), and the second recovery branch line (40) is equipped with a tenth valve (25).

7. The apparatus for recovering propylene product protective bed material during shutdown as described in claim 5, characterized in that, It also includes a propylene product protective bed buffer tank (29), the bottom of which is connected to one end of the third recovery branch line (41), the other end of which is connected to the main recovery line (38), the third recovery branch line (41) is connected to the end of the first recovery branch line (39) and the second recovery branch line (40) near the main recovery line (38), the top of which is connected to one end of the third stamping branch line (37), and the other end of the third stamping branch line (37) is connected to the main stamping line (34).

8. The apparatus for recovering propylene product protective bed material during shutdown as described in claim 7, characterized in that, The third recovery branch line (41) is equipped with an eleventh valve (28), and the third stamping branch line (37) is equipped with a pneumatic valve E (30) and a pneumatic valve F (31).

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