Abstract: In a small continuous flowing fixed-bed reactor, the nano-sized H-ZSM-5 catalyst with crystal size of20-50nm was applied to the catalytic cracking of butene from liquefied petroleum gas for propene synthesis. The catalytic performance of the nano-sized H-ZSM-5 catalyst was compared with that of two micro-sized H-ZSM-5 samples with crystal size of1-2and1-6μm, respectively. Under the same reaction conditions, the nano-sized H-ZSM-5 and the micro-sized H-ZSM-5 samples had approximately the same initial butene conversion and propene yield. However, the nano-sized H-ZSM-5 sample exhibited better resistance to coking and deactivation. Under the reaction conditions of WHSV=7 h-1, p=0.1 MPa, and θ=560 ℃, the butene conversion and propene yield over the micro-sized H-ZSM-5 samples decreased by about 50% after reaction for only28 h, whereas over the nano-sized H-ZSM-5 sample the reaction time could be prolonged to 120 h. According to the coke analysis results, the coking rate on the nano-sized H-ZSM-5 sample was lower than that on the micro-sized samples.

Key words: ZSM-5 zeolite, nano-sized zeolite, micro-sized zeolite, butene, catalytic cracking, propene