关键词: RFCC催化剂, 拟薄水铝石, Y型分子筛, Z/M, 反应性能

Abstract: A model catalyst for heavy oil catalytic cracking (RFCC) is prepared from rare earth super stable Y zeolite and pseudo-boehmite. The ratio of specific surface area of Y zeolite to substrate (Z/M) in hydrothermal RFCC model catalyst and its effect on catalytic cracking performance are studied by N₂ physical adsorption and advanced cracking evaluation equipment. The results show that the higher the content of pseudo-boehmite in RFCC model catalyst, the worse the ability of zeolite Y to resist high-temperature hydrothermal damage, and the Z/M ratio gets smaller. When the pseudo- boehmite mass fraction in the model catalyst reaches 30%, the specific surface area retention of zeolite Y is as low as 28.3%, and the Z/M ratio is only 0.8. The pseudo-boehmite content not only affects the hydrothermal stability of catalyst but also the morphology of catalyst. The higher the pseudo-boehmite content, the worse the morphology of catalyst microspheres. When the mass content of pseudo-boehmite is 30%, there were not only a lot of holes but also many cracks on the surface of catalyst microspheres. The evaluation results of RFCC model catalyst for residue catalytic cracking show that with the decrease of model catalyst Z/M ratio, the total yeilds of target liquefied petroleum gas(LPG) and gasoline gradually decrease, the light cycle oil yield increases, and the coke selectivity becomes poor.

Key words: RFCC catalyst, pseudo-boehmite, Y zeolite, Z/M ratio, reactivity