A Study On Modification Of Inner Mongolia Hard Kaolin Of Coal Measures And Its Application In FCC Catalysts

The structure and characteristic of acid and alkali modified kaolin of coal measures of Inner Mongolia was studied in this paper. The kaolin of Inner Mongolia and Suzhou with different molar ratio of n(SiO₂)/n(Al₂O₃) has been prepared by the mean of acid modification. The effect of the ratio of n(SiO₂)/n(Al₂O₃) on the kaolin performance, including BET surface area, pore distribution, pore volume, surface acidity, amount of acid sites and cracking capability, was examined by pyridine-TPD, nitrogen adsorption and the test of activity cracking. The results indicated that pore volume, BET surface area, surface acidity and cracking activity of the two kinds of kaolins increased obviously with the increase of the ratio of n(SiO₂)/n(Al₂O₃) when the ratio was always smaller than 20. After the ratio of n(SiO₂)/n(Al₂O₃) became more than 40, the nature of two kinds of kaolin went to stable. The pore radium ranged from 3nm to 10 nm. The results also showed that the acid intensity and cracking performance of Inner Mongolia Kaolin are all better than Suzhou Kaolin. Furthermore, FCC catalysts were synthesized of acid-treated kaolin, certain amount of kaolin and PREHY zeolite. We examined the effect of the ratio of n(SiO₂)/n(Al₂O₃)and the quantum of acid-treated kaolin on the activity of FCC catalysts. The results showed that surface acidity and cracking performance of FCC catalysts were related to the ratio of n(SiO₂)/n(Al₂O₃) of kaolin contained in the catalysts and that the amount of acid-treated kaolin improved the cracking performance of FCC catalysts. We prepared alkali-treated kaolin of Inner Mongolia with different molar ratio of n(SiO₂)/n(Al₂O₃). The effect of the ratio of n(SiO₂)/n(Al₂O₃) on the kaolin performance, including structure, physical nature, surface acidity, acid-quantum and cracking capability, was examined by XRD, Nitrogen adsorption, pyridine-TPD, and the test of cracking activity. The results indicated that the distribution of pore radium broadened and pore volume increased with the increase of the ratio of n(SiO₂)/n(Al₂O₃). Contemporarily, BET surface area, surface acidity and cracking activity raised up.The environment change of Si and Al were studied by MAS NMR when kaolin were calcined and treated by acid or alkali. The results showed that the activity was different because of different modality of Al atom. The order of acid and alkali...