Hydrotreating Performances Of Supported Pt、Pd Catalysts

During the combustion process, the sulfur-containing and nitrogen compounds in the oil will release the SOx, NOx and other compounds which could cause serious air pollution. In recent years, since quality standards about fuel products are being improved, hydrodesulfurization (HDS) and (HDN) is one of effective processes to remove sulfur element and nitrogen element. But trace amounts of nitride element will inhibit the further process of HDS and particularly will strongly adsorb on the acidic catalyst, reducing the catalyst activity, and even causing catalyst damage. Therefore, to develop new and efficient catalysts of hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) becomes increasingly important.This paper mainly focused on Pt and Pd noble metal catalysts. H-type MCM-41(HM) catalysts were prepared respectively by salt precursors, H2PtCl6, PdCl2and Al (NO3)3with different amounts of Al additive. The HDS performances of these catalysts were studied using a model fuel containing0.8%DBT in decalin. The results of NH3-TPD and H2chemisorption show that Al additive enhances the acidity of the catalyst and promote the dispersion of supported metal, and the hydrogenation activity and HDS activity of catalysts were significantly increased.The HDS and HDN performance of Pt/HM and Pd/HM catalysts were studied by model compounds DBT, quinoline (Q) and Decahydroquinoline (DHQ). Noble metal catalyst has good HDS activity, but low HDN activity. The nitrogen-containing compound strongly inhibited the HDS of DBT, raising the temperature, so the activity of catalysts can be restored, but the product selectivity is changed. In the HDN of Q, Q in the Pt and Pd catalyst has hydrogenation reaction and generates DHQ. Sulfur compounds strongly curb the HDN of Q, raising the temperature, a and the activity of Pt/HM catalyst can be restored, but the activity of Pd/HM catalysts can not be fully restored.