When the 800,000-ton plant was about to stop operating, there was severe catalyst loss; are there any effective solutions for addressing this issue?
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This post was last edited by dongliangsir on 2010-11-17 at 18:19. Our plant with a capacity of 800,000 tons is facing severe catalyst loss as it prepares to shut down – 20 tons of catalyst are lost each day, and adjustments made have not improved the situation. Is there any effective solution?
The main reasons for the high solid content are as follows: 1. The properties of the catalyst; if the fine particle content of the new catalyst is high, it cannot be recovered by a cyclone. In addition, the wear resistance of the catalyst, the storage of the catalyst, and whether moisture is present during transportation. The two catalysts wear each other down. Catalysts with poor hydrothermal stability also tend to have a higher particle size distribution. 2. The regenerator temperature is too high. 3. Excessive atomization volume of the feedstock nozzle and inappropriate nozzle selection lead to catalyst damage. 4. Excessive steam flow in the stripping section, among other factors, results in an excessively high linear velocity of the dilute phase and a high density of the dilute phase. 5. The spiral descent speed exceeds the required speed. 6. Coking occurs within the rotating chamber, and the coked masses block the material legs. The flap valve has clogged and cannot open properly. 7. Sinking and swirling fault (detected through voltage drop) or improper design/installation of the sinking and swirling mechanism. 8. Inappropriate material level in the settler; the operating environment of the flap valve is in an unstable state, which affects its performance. Judging from your situation, it’s likely that the equipment is broken or clogged; you’ll have to stop operation and open it up to take a look.
Has the 800,000-ton catalytic unit operated by you three been shut down? Was it due to the settlement vessel running out of fluid and thus coming to a stop, or was it due to a lack of raw materials?
When our plant was shut down, there was also significant leakage from the regenerator; it is estimated that this was caused by low reserve levels and excessive main air flow. After reducing the main air flow, the leakage decreased
Is the poster referring to the shutdown that occurs due to fluid leakage, or is the shutdown caused by the need to address the fluid leakage? It’s normal to stop operation, remove the agent, and run the fluidizing agent. If you say 20 tons per day, then it’s not really a shutdown process; 20 tons per day is quite a lot. What is the solid content of the slurry? Should it be processed in a regenerator or a settler? If it’s processed in a settler, then adjust the amount of steam, the amount of feedstock, and the volume in the stripping section. If the regenerator stops working, adjust the main air volume and pressure; it’s possible that the flap valve is stuck. If that doesn’t work, stop the main air supply and then restart it. If that still doesn’t work, shut down the equipment for maintenance – it’s possible that the material leg is broken. In our case, the secondary centrifugal material legs in group 6 broke even before 20 tons of material were processed. I hope there isn’t a problem with the primary centrifugal unit. 20 tons – there’s really no need to keep it running; turn it off
Reply to 3# zhaojiong1999: Stop work for the winter
Reply to 5# hhwangsong: All three spindles are at 400 degrees; there’s no choice but to stop production
First, it is necessary to identify the cause and location of the catalyst loss. If the loss occurs in the regenerator, it is recommended to check whether there are any leaks in the heat exchangers inside the regenerator； If there is leakage from the settler, is the solid content of the slurry at the bottom of the fractionator very high? ； Another issue is the damage to the catalyst caused by the feed nozzle.
Actually, someone in the forum asked a similar question; it is suggested that the original poster ask such questions after doing some searching first. The reasons for the catalyst issue are: 1. The quality of the balancing agent used in the device itself is poor ； 2. Damage caused by burning fuel during startup ； 3. Thermal collapse caused by excessive steam in the lift pipe ； 4. Negative impacts of high regenerator temperature ； 5. Catalyst wear may be caused by high local linear speeds ； 6. A high bed level leads to an increased catalyst level in the cyclone leg, resulting in a shorter settling time for the catalyst within that leg or in gas-phase carryover of the catalyst ； In two out of the three sets of centrifuges, there were catalyst sintered hard deposits at the junctions between the ash hopper and the material legs; the main cause of the obstruction in these material legs was catalyst sintering due to excessively high local temperatures. Recommended measures: 1. Take samples and analyze the catalysts in the three centrifuges to determine their fine particle content; 2. Pay attention to controlling the quality of steam in the regeneration system, and consider reducing the amount of steam supplied; 3. Ensure that tail burning does not occur again by appropriately reducing the amount of catalyst stored in the regenerator; 4. Control the temperature of the regeneration bed to avoid significant fluctuations or excessively high temperatures; 5. Replace the catalysts at appropriate times; 6. Maintain an appropriate level of burning intensity in the regenerator, which can be achieved by slightly increasing the pressure in the regenerator.