Revamps 2026 Issue

engineering/subject matter expert (SME), and operations. The final repair should be documented on the air grid noz - zle and included in the turnaround report. If nozzles are plugged, estimates on the air loss should be calculated. Regenerator cyclones As part of the regenerator inspection, the regenerator cyclones should be inspected at every turnaround. Even with cyclones just completing their first cycle, they should still be reviewed for unexpected wear. Common areas of damage are: • Primary cyclone inlet. • Target area of primary and secondary cyclone (back side of cyclone). • First-stage outlet tubes. • Entrance to the crossover ducts (often in the corner) and in the crossover. • Second-stage hopper cones and lined dipleg stubs. Damage should be compared to the notes from the prior turnaround. If the damage has increased, review the pro - cess velocities for changes in cyclone velocities, increases in regenerator temperatures, and/or afterburn in the cyclones. Also note any changes in regenerator catalyst losses, cata - lyst fines content, and regenerator electrostatic precipitator (ESP) or scrubber fines particle size distribution. As cyclones age, there can be concerns with cyclone metal weldability (i.e., difficulty in attaching anchors). There can also be issues with general refractory roughness, which can increase fines losses and may require replacing the cyclones in the next turnaround. Units that still have condensate and/or steam dilute-phase injection distributors/nozzles should consider whether they can be eliminated. These injection systems have a higher risk of damage to internals from impingement, along with loss of energy and increased velocities. Otherwise, these should be repaired if there are signs of damage. Catalyst transfer lines Transfer lines, such as the spent catalyst standpipe, U-bend and lift system (if so designed), and regenerator standpipe and riser, are subject to severe erosion and thermal condi - tions. Refractory is used to protect metal from erosion and excessive temperature, so its integrity is crucial. Aeration taps/distributors and instrument taps should all be inspected for cleanliness. These taps should again be checked when the unit is first pressurised with the air blower to ensure they are clear. Slide valves Slide valves are also subject to erosion and thermal issues. Modern designs are refractory-lined, and the refractory will need to be inspected. Erosion to the guides and gate should be noted in the turnaround report. Process condi - tions (valve differential pressure [ΔP] and opening) should be investigated if excessive damage is noted. Replacement is often recommended when repair time approaches the critical path or repair costs approach 50% of a new valve. Unit monitoring of slide valves during operations between turnarounds can be used to help indicate slide gate wear

Figure 1 Air distributor nozzle erosion

standpipes, should be inspected for cleanliness and eleva- tions verified, including the elevation of any internal piping. Any restriction orifices (RO) should be verified. A list of RO locations, types (orifice plate/RO in union coupling/drilled valve), and sizes should be created. All RO installations should be verified prior to unit start-up. All thermocouples that were not reading or appeared to be inaccurate should be removed, checked for condition, and verified as working. Thermowells that are damaged should be replaced. Any damaged thermowells that could not be repaired should be noted in the turnaround report. Spent catalyst distributor/regen outlet – standpipe The regenerator outlet debris guard should be inspected for damage and plugging. Note if excessive debris (usually refractory) was found after catalyst removal. Any damage should be repaired. The regenerator air distributor nozzles should be inspected for erosion and plugging. A good practice is to have an air grid pattern drawing and note damaged or plugged nozzles Any damage to the aeration ring for the standpipe inlet should be noted and repaired. If inlet aeration was impaired, it may be worthwhile noting changes in aeration rate and regenerator standpipe operation to determine when the failure occurred. An alternate design may be needed if loss of aeration has occurred in prior runs and affected the regenerator stand - pipe performance. Damage to other internal piping for aeration or other purposes should similarly be reviewed for impact on performance and possible upgrade. Regenerator air distributors The regenerator air distributor nozzles should be inspected for erosion and plugging (see Figure 1 ). A good practice is to have an air grid pattern drawing and note damaged or plugged nozzles. The turnaround group may want engi - neering to note nozzles requiring repair with spray paint as well as a drawing. Nozzles may need to be plugged if they are severely damaged or causing impingement. A repair plan should be developed between the turnaround group, process

Revamps 2026