The Application Study On Modification Of Inner Mongolia Kaolin In FCC Desulphurization Catalysts

With environmental protection law and regulation gradually strict, the sulfur content of gasoline reducing is imperative. In actual numerous desulfuration methods, it is the most attractive that organic sulphur compound cracks and extricates at original place in catalytic cracking reaction process to reduce sulfur content of catalytic gasoline. Base material of FCC catalyst (kaolin) was treated to be the assistant having cracking and desulfuration activity, which could accomplish desulfuration during the cracking process. The effect which treatment method had on the structure, characteristic and cracking desulphurization performance of acid and alkali treated kaolin of Inner Mongolia was studied in this paper.During the acid and alkali treatment, the change trend of the structure and performance of acid and alkali treated kaolin were given stress analysis.The alkali- treated kaolin with different molar ratio of n(SiO₂)/n(Al₂O₃) had been prepared. The effect of the ratio of n(SiO₂)/n(Al₂O₃) on the kaolin performance, including surface acidity, acid type, amount of acid sites and cracking desulphurization capability, were examined by pyridine-TPD, IR and the test of cracking activity. The results showed that the amount and the intensity of acid site of acid-treated kaolin were all higher than alkali-treated kaolin. The results of cracking desulphurization performance were conversed. The results also indicated that surface acidity and cracking activity of the alkali-treated kaolins had an obviously disciplinary change with the decrease of the ratio of n(SiO₂)/n(Al₂O₃), and the contents of B and L acid were changed through the adjustment of different molar ratio of n(SiO₂)/n(Al₂O₃).For the sake of increasing the hydrogen transfer capability, the metal with the hydrogen transfer capability was loaded on the alkali-treated kaolin. Different methods of loading metal including dipping, ion-exchange, mix and spinel were examined.The cracking desulphurization performances of the catalysts loading different metal were different. The results showed that loading appropriate metal on the alkali-treated kaolin with appropriate method could improve the hydrogen transfer capability and increase the percent of medium intensity acid site, so the cracking desulphurization performances of the catalysts were enhanced.