PETR 42 |
| A Gibbs free energy model for selective oxidation was developed which explains why Pt and Pd CO promoters produce NOx from HCN and NH3, the main products of coke burning. The model also predicts that base metal oxides are less likely to make NOx. High activity base metal CO promoters gave only marginally lower NOx however. Experimental data then showed that high activity CO promoters are heat and mass transfer limited, leading to overheating of these microspheres with respect to the rest of the fluid bed. NOx selectivity was not improved for low activity Pt promoter, but lowering the activity of the base metal CO promoters gave ca. 50% lower NOx than Pt or Pd, in agreement with the Gibbs free energy model. A partial burn additive was also identified which has little CO oxidation activity, but converts HCN and NH3 to N2 at ca. 95% yield. |
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7th International Symposium on Advances in Fluid Cracking Catalysts (FCCs)
8:30 AM-11:45 AM, Monday, 11 September 2006 Palace -- Telegraph Hill, Oral
Division of Petroleum Chemistry |