Sandie Brandenberger and Ka Lok (UOP)

Directionally the higher O2 level is better for metal dispersion during oxidization. UOP recommends a minimum of 5% with typical maximum O2 content of 8-10 mol% based on the seal oil combustion limits. Dry seals or nitrogen purge seals allow higher O2 content without explosive conditions. If there is a history of coke ball formation or damage to reactor internals, maintaining a maximum of 3 mol% oxygen during the oxidation step should be considered and should be determined on case-by-case basis. When O2level is lower than desirable level, extending the hold time during the oxidization step will directionally improve metal dispersion.