Pressurized Regenerator Inspection Guidelines:
Following are recommended guidelines for inspecting a Pressurized regenerator. The Disengaging Hopper and Lock Hopper are included in these recommendations. The order of the recommendation is from the top down (starting at the top of Disengaging Hopper and working down through the regenerator to the Lock Hopper).
Disengaging Hopper
If the Regenerator is being emptied just for screen cleaning then the catalyst from the Regenerator may be transferred to the Disengaging Hopper using the Regenerator Unload Operation. In this case the Disengaging Hopper will remain full of catalyst. The Disengaging Hopper should still be isolated from the reactor circuit, depressured and kept under nitrogen atmosphere. In this case the Disengaging Hopper internals will not be inspected. However, it will still be possible to inspect and clean the screen insert in the Disengaging Zone gas outlet line. If this is done then it is essential that the Disengaging Hopper be completely and positively isolated, hydrocarbon freed and kept under nitrogen blanket. The open flange should be covered while the screen insert is removed, inspected, and cleaned. Then the screen insert should be reinstalled immediately and the system closed.
If catalyst is being replaced then the Disengaging Hopper will be emptied. It is normal practice to inspect the Disengaging Hopper from the manway. Catalyst remaining in the bottom head can be vacuumed out or swept into the bottom withdrawl nozzle and removed bottom nozzle. The catalyst restriction orifice on the pipe into the Disengaging Zone should be inspected to make sure it is free of obstruction. This is best done with a video camera / boriscope.
It is not necessary to dismantle the small I.D. middle and bottom sections of the Disengaging Hopper. However, if a suitable camera is not available to do the inspection without dismantling then it will be necessary to open these sections also.
Regenerator
There are 3 possible stages of regenerator inspection:
1. Before catalyst is unloaded
2. After catalyst is unloaded but before the inner screen in removed.
3. After the inner screen in removed.
Before Catalyst is Unloaded:
It is useful to evaluate the level of the catalyst in the regenerator before catalyst is removed. This helps identify any possible operating problems. In order to do this the line between the bottom isolation valve and the top of the regenerator must be removed. The top manway (usually nozzle FB on UOP dwg) and the top side manway (usually nozzle AF on UOP dwg) must be opened before catalyst is unloaded. The following can be observed
From the Top/side manway:
1. Note the catalyst level in the burn zone annulus. It should be completely full up to the catalyst pipes from the inlet catalyst distributor pot. On some units this catalyst level has been observed to be low. So an operating problem could be determined.
2. Take note of the dust on the top of the inner screen. Is there whole catalyst pills mixed with the dust or is there just dust?
3. Take note of any catalyst or other material sitting on the wire mesh screen between the vessel shell and the top of the outer screen.
From the Top manway/ catalyst inlet:
4. Inspect the catalyst inlet distributor pot. Take note of the catalyst level in this pot. This pot should be full of catalyst.
5. Take note of the color of the catalyst in the pot. In some units white catalyst has been observed in this pot, indicating an operating problem.
6. Take note if all outlet pipes from the pot are covered with catalyst.
7. Take note if there is any obvious coke growth in the bottom of the pot. Coke growth in this location has been observed on several units, indicating an operating problem.
8. Further inspection will be done after catalyst is fully unloaded. At this point the manways can be closed and the catalyst inlet pipe to the top of the regenerator can be reassembled so that catalyst can be unloaded from the Regenerator and Disengaging Hopper.
After Catalsyt Has Been Unloaded but Before Inner Screen is Pulled
9. Check the catalyst transfer pipe durolok coupling to make sure they are still fully intact. This is most easily done before the inner screen is pulled. These catalyst transfer pipes are not normally dismantled during regenerator inspection. They are left fully assembled.
10. Take note of the catalyst remaining in the top distributor pot. Is the catalyst uniformly black or is there some while catalyst mixed in?
11. After vacuuming out the remaining catalyst take note if there is any indication of coke growth around the internal manway flange.
12. Check each catalyst transfer pipe to verify there was no obstruction in the line.
13. Open the internal manway and take note of the condition of the existing gasket. This gasket was originally specified to be graphite. We have since found that this material is a poor choice. Over time graphite can burn at the conditions on the underside of the internal manway. So the graphite will eventually disappear over time. A graphite gasket should no longer be used at this location. Operating problems can be caused by excessive leakage through this manway. UOP does not have a recommended alternative gasket. At this time UOP recommends seal welding the internal manway shut. This mean the weld will have to be ground out to gain access in the future.
14. Enter the internal manway and take measurements of the catalyst annulus. On some units the inner screen has become bent so the catalyst annulus size will vary from one side of the regenerator to the other. This is usually a problem only on very large unit but it is necessary to spot check the annulus size to be sure this is not happening. The specified annulus can be found in the UOP 305 Project Specification. It is normally 228 mm for a Pressurized regenerator. Prepare a thin scale about 300 mm long so that it can be inserted through the inner screen until it contacts the outer screen. Take some spot measurements to verify that the annulus remains uniform per the 305 specification. If the annulus is found to be falling outside of the specified tolerance then it is advisable to take a complete set of measurements (every 300 mm of screen length at every 45 around the circumference) in order to document the magnitude of the problem.
15. Once the annulus measurement is complete the inner screen can be removed and the remainder of the inspection can be completed.
Inspection After the Inner Screen Has Been Lifted
16. Carefully examine the inner screen profile wire for damaged areas and repair as necessary.
17. Carefully examine the outer screen profile wire for damaged areas and repair as necessary.
18. It is common practice to cut access holes into the bottom blankoff section of the outer screen so that catalyst dust that has settled between the vessel shell and the bottom of the outer screen can be vacuumed out. These access holes will then be rewelded after cleaning is complete.
19. It is common practice to cut access holes into the wire mesh screen (see detail A1) at the top of the outer screen. This allow catalyst dust to be vacuumed off of the top of the interzonal baffle (Detail E1).
20. On some older Pressurized Regenerator designs there may be 2 internal manways in the bottom of the catalyst distributor pot. The larger O.D. manway is too large to remove from the distributor pot. If this larger manway is there it should be seal welded in place around the outside diameter.
21. Take note of the catalyst plugging of the inner and outer screen. Document any clear patterns where the screen is particularly heavily plugged or not.
22. Thoroughly clean catalyst from inner and outer screen.
23. Take spot measurements of the distance between the regenerator shell and the outer screen. This will give an indication if the outer screen is warping.
24. Take spot measurements of the distance between the outer screen and the regeneration gas inlet distributor baffle (Section J1-J1 on UOP dwg). This will also give an indication if the outer screen is warping.
25. Take note of the condition of all nozzles in the top head of the regenerator. Iron/nickel chloride salt corrosion products may be plugging the non flowing nozzles such as the impulse line nozzles and TI nozzles.
26. The chlorinatin zone area should be entered from above and inspected prior to any cleaning in the chlorination zone. If necessary take out the removable guide vane (Section D4-D4) in order to gain access. Note the following items about the chlorination zone:
- Have the guide vanes been melted? If yes, this is an indication of highly coked catalyst entering the chlorination zone. Any damaged areas should be ground smooth. Generally it is not necessary to replace damaged guide vanes.
- Are there any clumps of catalyst sitting in the bottom of the chlorination zone that did not flow out when the catalyst was unloaded?
- Is there any catalyst sticking to the chlorination zone cylinder at any point?
- Is the space between the vessel shell and the chlorination zone outer cylinder filled with catalyst dust? This is normal and does not need to be cleaned out.
27. The drying zone can be entered from the lower manway (normally nozzle CF on UOP dwgs). Hopefully there is nothing out of the ordinary to see here. Note the following items about the drying zone:
- Expect the manway to be 25% filled with catalyst dust when the manway is opened. So prepare a bag to collect this dust or it will blow everywhere. Take note if there is any whole catalyst pills in this dust.
- Take note of any wear pattern on the drying zone wall that is in line with the outlet of the vapor tunnels. This is not expected but one customer has reported errosion of the wall at this point so it is advisable to check.
- Take note of any debris remaining in the bottom of the drying zone. Normally there is nothing. Some customers will install a plug in the drying zone outlet during a
Pressurized Regenerator Inspection Guidelines:Following are recommended guidelines for inspecting a Pressurized regenerator. The Disengaging Hopper and Lock Hopper are included in these recommendations. The order of the recommendation is from the top down (starting at the top of Disengaging Hopper and working down through the regenerator to the Lock Hopper).Disengaging HopperIf the Regenerator is being emptied just for screen cleaning then the catalyst from the Regenerator may be transferred to the Disengaging Hopper using the Regenerator Unload Operation. In this case the Disengaging Hopper will remain full of catalyst. The Disengaging Hopper should still be isolated from the reactor circuit, depressured and kept under nitrogen atmosphere. In this case the Disengaging Hopper internals will not be inspected. However, it will still be possible to inspect and clean the screen insert in the Disengaging Zone gas outlet line. If this is done then it is essential that the Disengaging Hopper be completely and positively isolated, hydrocarbon freed and kept under nitrogen blanket. The open flange should be covered while the screen insert is removed, inspected, and cleaned. Then the screen insert should be reinstalled immediately and the system closed.If catalyst is being replaced then the Disengaging Hopper will be emptied. It is normal practice to inspect the Disengaging Hopper from the manway. Catalyst remaining in the bottom head can be vacuumed out or swept into the bottom withdrawl nozzle and removed bottom nozzle. The catalyst restriction orifice on the pipe into the Disengaging Zone should be inspected to make sure it is free of obstruction. This is best done with a video camera / boriscope. It is not necessary to dismantle the small I.D. middle and bottom sections of the Disengaging Hopper. However, if a suitable camera is not available to do the inspection without dismantling then it will be necessary to open these sections also.RegeneratorThere are 3 possible stages of regenerator inspection:1. Before catalyst is unloaded2. After catalyst is unloaded but before the inner screen in removed.3. After the inner screen in removed.Before Catalyst is Unloaded:It is useful to evaluate the level of the catalyst in the regenerator before catalyst is removed. This helps identify any possible operating problems. In order to do this the line between the bottom isolation valve and the top of the regenerator must be removed. The top manway (usually nozzle FB on UOP dwg) and the top side manway (usually nozzle AF on UOP dwg) must be opened before catalyst is unloaded. The following can be observedFrom the Top/side manway:1. Note the catalyst level in the burn zone annulus. It should be completely full up to the catalyst pipes from the inlet catalyst distributor pot. On some units this catalyst level has been observed to be low. So an operating problem could be determined. 2. Take note of the dust on the top of the inner screen. Is there whole catalyst pills mixed with the dust or is there just dust? 3. Take note of any catalyst or other material sitting on the wire mesh screen between the vessel shell and the top of the outer screen.From the Top manway/ catalyst inlet:4. Inspect the catalyst inlet distributor pot. Take note of the catalyst level in this pot. This pot should be full of catalyst.5. Take note of the color of the catalyst in the pot. In some units white catalyst has been observed in this pot, indicating an operating problem.6. Take note if all outlet pipes from the pot are covered with catalyst. 7. Take note if there is any obvious coke growth in the bottom of the pot. Coke growth in this location has been observed on several units, indicating an operating problem.8. Further inspection will be done after catalyst is fully unloaded. At this point the manways can be closed and the catalyst inlet pipe to the top of the regenerator can be reassembled so that catalyst can be unloaded from the Regenerator and Disengaging Hopper.After Catalsyt Has Been Unloaded but Before Inner Screen is Pulled9. ตรวจ durolok โอนเศษท่อ coupling ให้แน่ใจว่าพวกเขาจะยังคงเหมือนเดิมทั้งหมด นี้ง่ายสุดแล้วก่อนดึงหน้าจอภายใน ท่อเหล่านี้โอนเศษจะไม่ปกติรื้อถอนในระหว่างการตรวจสอบการกำเนิดใหม่ พวกเขาเป็นซ้ายเต็มประกอบด้วย10. รับทราบของเศษที่เหลือในหม้อจำหน่ายสูงสุด เศษสม่ำเสมอเมื่อเทียบเคียงสีดำ หรือมีบางขณะที่เศษผสม11. หลังจาก vacuuming ออกเศษเหลือใช้หมายเหตุถ้ามีข้อบ่งชี้ใด ๆ ของโค้กเติบโตรอบ ๆ หน้าแปลนภายใน manway12. ตรวจสอบท่อแต่ละโอนเศษเพื่อการตรวจสอบมีไม่อุดตันในบรรทัด13. เปิด manway ภายใน และรับทราบเงื่อนไขของปะเก็นที่มีอยู่ ปะเก็นนี้เดิมถูกระบุเป็น แกรไฟต์ ตั้งแต่เราได้พบว่าวัสดุนี้อึดอัด เวลา แกรไฟต์สามารถเขียนที่เงื่อนไขในการ underside ของ manway ภายใน ดังนั้นแกรไฟต์ที่จะหายในที่สุดเวลาผ่านไป ไม่ควรใช้เป็นปะเก็นก้านในตำแหน่งนี้ ปัญหาการปฏิบัติงานอาจมีสาเหตุจากการรั่วไหลมากเกินไปผ่าน manway นี้ UOP มีปะเก็นอื่นแนะนำ ขณะนี้ UOP แนะนำตรา เชื่อม manway ภายในปิด นี้หมายความว่าการเชื่อมจะต้องดินออกเพื่อเข้าในอนาคต 14. Enter the internal manway and take measurements of the catalyst annulus. On some units the inner screen has become bent so the catalyst annulus size will vary from one side of the regenerator to the other. This is usually a problem only on very large unit but it is necessary to spot check the annulus size to be sure this is not happening. The specified annulus can be found in the UOP 305 Project Specification. It is normally 228 mm for a Pressurized regenerator. Prepare a thin scale about 300 mm long so that it can be inserted through the inner screen until it contacts the outer screen. Take some spot measurements to verify that the annulus remains uniform per the 305 specification. If the annulus is found to be falling outside of the specified tolerance then it is advisable to take a complete set of measurements (every 300 mm of screen length at every 45 around the circumference) in order to document the magnitude of the problem.15. Once the annulus measurement is complete the inner screen can be removed and the remainder of the inspection can be completed.Inspection After the Inner Screen Has Been Lifted16. Carefully examine the inner screen profile wire for damaged areas and repair as necessary.17. Carefully examine the outer screen profile wire for damaged areas and repair as necessary.18. It is common practice to cut access holes into the bottom blankoff section of the outer screen so that catalyst dust that has settled between the vessel shell and the bottom of the outer screen can be vacuumed out. These access holes will then be rewelded after cleaning is complete.19. It is common practice to cut access holes into the wire mesh screen (see detail A1) at the top of the outer screen. This allow catalyst dust to be vacuumed off of the top of the interzonal baffle (Detail E1).20. On some older Pressurized Regenerator designs there may be 2 internal manways in the bottom of the catalyst distributor pot. The larger O.D. manway is too large to remove from the distributor pot. If this larger manway is there it should be seal welded in place around the outside diameter. 21. Take note of the catalyst plugging of the inner and outer screen. Document any clear patterns where the screen is particularly heavily plugged or not.22. Thoroughly clean catalyst from inner and outer screen.23. Take spot measurements of the distance between the regenerator shell and the outer screen. This will give an indication if the outer screen is warping.24. Take spot measurements of the distance between the outer screen and the regeneration gas inlet distributor baffle (Section J1-J1 on UOP dwg). This will also give an indication if the outer screen is warping.25. Take note of the condition of all nozzles in the top head of the regenerator. Iron/nickel chloride salt corrosion products may be plugging the non flowing nozzles such as the impulse line nozzles and TI nozzles. 26. The chlorinatin zone area should be entered from above and inspected prior to any cleaning in the chlorination zone. If necessary take out the removable guide vane (Section D4-D4) in order to gain access. Note the following items about the chlorination zone:- Have the guide vanes been melted? If yes, this is an indication of highly coked catalyst entering the chlorination zone. Any damaged areas should be ground smooth. Generally it is not necessary to replace damaged guide vanes.- Are there any clumps of catalyst sitting in the bottom of the chlorination zone that did not flow out when the catalyst was unloaded?- Is there any catalyst sticking to the chlorination zone cylinder at any point?- Is the space between the vessel shell and the chlorination zone outer cylinder filled with catalyst dust? This is normal and does not need to be cleaned out.27. The drying zone can be entered from the lower manway (normally nozzle CF on UOP dwgs). Hopefully there is nothing out of the ordinary to see here. Note the following items about the drying zone:- Expect the manway to be 25% filled with catalyst dust when the manway is opened. So prepare a bag to collect this dust or it will blow everywhere. Take note if there is any whole catalyst pills in this dust. - Take note of any wear pattern on the drying zone wall that is in line with the outlet of the vapor tunnels. This is not expected but one customer has reported errosion of the wall at this point so it is advisable to check.- Take note of any debris remaining in the bottom of the drying zone. Normally there is nothing. Some customers will install a plug in the drying zone outlet during a
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