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Re:loss of catalyst FCCU

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Some years ago we had a similar problem in one of our VGO Orthoflow KBR units. We had erosion in regenerator cyclons and also some problems in regenerator air grid. The APS in e-cat was progressively increased (also APS in 4th stage fines). We manage to keep the unit running in such conditions during one year.  But the increase in APS was progressive, going from 85 to 105 microns during this year, and we don’t really have ASP higher than 100 microns during a long period (just some weeks previous to the scheduled shutdown). Your current situation seems to be worst than ours.
The strategy we use was to increase fresh catalyst addition (you may have some problems to maintain MAT unit at optimum level), recycle e-cat+fines and carefully adjust areations in standpipes to keep the coarser e-cat fluidized and circulating. Standpipes, slide valves and bends would be the first points were you could experience problems. It is important to monitor circulation and fluidization at these points, and increase areation if necessary

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