酸和碱处理对内蒙古煤系高岭土结构和裂化性能的影响

Effects of alkali and acid modification on catalytic cracking behaviors of Inner Mongolian coal-measure hard kaolin

利用NaOH溶液和HC l溶液分别对内蒙古煤系硬质高岭土进行酸和碱处理。采用固体核磁共振、BET、TPD以及裂化活性测试(在小型固定床上以酸处理高岭土对大港轻柴油进行催化裂化)等分析方法对比研究了煤系高岭土酸和碱处理后物化性能和裂化性能变化。结果表明,酸和碱处理都可以使高岭土获得(2-8)nm的孔径分布,并获得较好的催化裂化性能;A l(Ⅳ)有利于裂化反应,可以通过酸和碱反应改变高岭土中A l(Ⅳ)的比例来调节其裂化性能;酸处理后的高岭土酸性位数量明显高于碱处理土;碱处理高岭土的裂化性能优于酸处理高岭土。

Inner Mongolian coal-measure hard kaolin was treated respectively by NaOH and HCI solution. Using solid-state magic angle spinning nuclear magnetic resonance （solid-state MAS NMR）, BET, TPD and cracking activity test, changes of the kaolin in physicochemical properties and cracking activity after acid and alkali modification were studied. The results showed that both acid and alkali modification endowed the kaolin with particle size of （ 2 - 8 ） nm and better catalytic cracking activity. AI （Ⅳ） favored catalytic cracking, whose proportion could be changed by acid and alkali modification to adjust its cracking behaviors. Acidity sites of acid-modified kaolin was more than that modified by alkali, while alkali-modified kaolin exhibited superior cracking activity to that modified by acid.