Regarding the issue of catalyst loss

1. Are there any issues with the design?； 2. Are there any issues with the installation quality of the centrifuge? ； 3. Is there a problem with the fluidization in the settler? ； 4. Is there a problem with the level indicator of the settler? ； 5. Is there any damage to the catalyst? ； 6. Is the processing load deviating too much from the design? Please make an analysis and judgment based on the operational parameters at the site.

1. Recalculate whether the operating linear speed of the centrifuge is within the designed range. 2. Check the operational data regarding the pressure drop in the centrifuge to see if there are any fluctuations. 3. Determine the condition of material sealing at the feed leg of the centrifuge during startup. 4. What is the connection style between the outlet of the lift pipe and the centrifuge?

Most of the catalyst loss comes from the settler! Well, you need to figure out first whether this catalyst issue is due to wear and tear or to problems with the separation efficiency of the settler. If a particle size analysis has been conducted and it turns out that there is a large amount of fine catalyst powder, then it’s necessary to figure out ways to reduce catalyst wear. Consider whether those adjustments might, compared to before, contribute to the catalyst being ground into smaller particles. If there is no issue with the particle size distribution, then we need to consider the suggestions mentioned by those above. One important aspect is to figure out how to adjust the operating conditions of the centrifuge; there aren’t many options available – essentially, it involves adjusting the inlet linear speed and the depth of the material legs. We should also consider whether the fluidization in certain sections of the material legs is not optimal, and whether there might be clogs in the flap valves caused by coke particles. It’s advisable to adjust the level of material in the settler and observe its movement. Try changing the amount of stripping steam; observe for a few more days! If there are no more options, then try to keep the pressure stable – this is key to reducing leakage.

Please explain the relationship between \"processing load\" and catalyst degradation!

If the processing load is too low, the inlet linear speed of the centrifuge is low； If the processing load is too high, the inlet linear speed of the centrifuge is too high. Both of these situations affect the efficiency of the centrifuge, leading to increased catalyst loss.

During the operation of the unit, leakage from the settler is a **problem**, as it can lead to blockages in the fractionation tower, as well as wear and blockages in the slurry pipelines. I largely agree with what was said on floor 4: first, examine the particle size distribution of the catalyst to eliminate the cause of fine powder, and then try adjusting the level in the settler, changing the processing load and steam volume, as well as reducing the steam used in the stripping section to prevent any impact on the fluidization state in the leg area. During normal operation of the device, there are generally no design or equipment defects, and adjustments to operating conditions usually resolve such issues. Good luck!

According to the common approach of shifting responsibility, one should first check the particle size distribution of the catalyst to see if it is caused by excessive fineness. An excess of fine particles can be due to a high amount of fresh catalyst powder, or it may result from wear of the catalyst caused by overly high processing temperatures; it is even more likely to be caused by improper gas lift operations and overheating during regeneration. After ruling out the issue of catalyst fines, it is also necessary to check whether the inlet linear velocity of the cyclone is too low and whether the material seal at the cyclone’s discharge end is appropriate.

The most troublesome aspect of FCC units is catalyst deactivation, with settlers being the most problematic element. The main solution is to check and adjust the linear velocity at the inlet of the centrifuge; to address this issue, it is necessary to increase the amount of slurry sent outside the unit and reduce the solid content in the slurry.

1. Check whether the linear velocity at the cyclone inlet is too low. 2. Verify whether the regeneration temperature is too high, or whether the catalyst undergoes thermal decomposition in contact with steam. 3. Ensure that the level of the material in the gas lift system is neither too high nor too low. 4. Check whether the processing load is excessive. 5. Confirm whether a flow control orifice plate is installed near the flap valve; excessive backflow pressure may prevent the flap valve from closing properly

What is the solid content of your slurry? Is it greater than 20g/l? The ash content of the slurry could be considered, and the collected ash can be subjected to particle size analysis. If there is a lot of fine powder, look for reasons related to catalyst crushing; this could be due to differences in strength among different catalysts, or it might be because the linear speed of the feed nozzle is too high. There are also other reasons mentioned by the colleagues above. From what you’ve described, the inspection of the centrifuge itself shows no problems, so compare the operating conditions and the quality of the catalyst one by one to see which factor causes the most changes.

Catalyst loss is a very complex issue that cannot be resolved immediately. First, check whether it runs from one side or from both sides. It’s best to find a professional catalyst particle analyst to examine its shape and size. Only then can a more accurate judgment be made. Upload the particle analysis report.

1. If you run from both the reverse and normal sides, check the temperature of the superheated steam to see if a thermal breakdown has occurred. 2. If possible, check the pressure of the two devices as well. 3. If the agent is leaking while in operation, it may be that the valve plate of the wing valve does not operate properly; in such cases, the pressure can be increased significantly as long as it remains within acceptable limits.

Have you replaced the nozzles recently? At the FCC where I used to work, severe catalyst loss occurred after new nozzles were installed.

1. Is there a problem with the flap valve of the cyclone separator? 2. Is the catalyst too fine? 3. Is the gas velocity too high?