关键词: 分子筛, 纳米晶, 柴油, 加氢精制, 尺寸效应

Abstract: Zeolite Y nanocrystals were synthesized with water glass and sodium aluminate as raw materials and cetyltrimethylammonium bromide as dispersant. The effect of crystallization temperature, crystallization mode, the amount of directing agent and its aging time on the crystal size of zeolite Y was investigated systematically, and these synthesized samples were characterized by XRD, TEM and N2 adsorption-desorption techniques. Results show that the aging time of directing agent is the main factor affecting the crystal size of zeolite Y. Zeolite Y nanocrystals (50-100 nm) can be obtained under the conditions of a crystallization temperature of 100 ℃, using a directing agent aged for 19 days and adding 20 % of said agent to the synthesis system. The obtained nano-zeolite Y samples possess high external specific surface area: its BET surface area is 658 m2/g, which is equivalent with that of the conventional commercial product; its external surface area is 53.4 m2/g, which is much higher than that of the latter (1.0 m2/g). NiMo hydrofining catalyst containing nano-zeolite Y exhibits higher hydrodesulfurization and hydrodenitrogenation activities as compared with reference catalyst containing conventional zeolite Y, which shows valuable size effect.

Key words: molecular sieve, nanocrystal, diesel, hydrofining, size effect