We have carried out maintenance on our CCR and want to re-load the used catalyst, but part of the batch is contaminated with high carbon (heel) catalyst. Is there a proven technology for removing the heel pellets?

A catalyst service provider can conduct density grading of the used CCR catalyst, where the pellets are segregated by individual particle density (carbon level). They will be able to guarantee an average carbon number for each drum as well as a peak carbon content lower than 8, 10 or 12 wt%. You should check with your supplier to establish what maximum carbon numbers (average and peak) they would allow for re-loading and inform the service provider accordingly. This technology has been used for many years and is considered proven.