摘要
根据FCC汽油的PONA(Paraffins,Olefins,Naphthenes and Aromatics)分析结果,确定了不同结构的FCC汽油模型化合物。采用半经验量子力学方法计算了所选模型化合物分子的尺寸,用分子动力学方法计算了模型化合物分子在Y、ZSM-5和β分子筛孔道中的扩散能垒。计算结果表明,模型化合物分子在分子筛中的扩散能垒与其自身的尺寸和分子筛孔径大小密切相关。Y和β分子筛孔径较大,不同结构模型化合物分子在这两种分子筛中的扩散能垒差别不大;ZSM-5分子筛的孔径较小,与汽油模型化合物分子尺寸相近,不同结构模型化合物分子在ZSM-5分子筛中的扩散能垒具有明显的差别。实验结果证明,ZSM-5对FCC汽油具有优良的裂化选择性,能够使汽油中的烯烃选择性地裂化为C3、C4烯烃。在降低FCC汽油烯烃含量的同时,实现了增产丙烯的目的。
According to PONA （Pareffins, Olefins, Naphthenes, Aromatics） analytic results of FCC gasoline, some model compounds were selected. The molecular sizes of selected model compounds were calculated by the semi-empirical quantum mechanical method and the molecular diffusion energy barriers of these model compounds in the channels of ZSM-5, Y and β zeolites were calculated by molecular kinetics method. It was found that molecular diffusion energy barriers were sensitive to the sizes both of model compounds and pore dimensions of zeolites. Compared with ZSM-5, the channels in Y and β were much wider, there was no difference between the molecular diffusion energy barriers of these model compounds in them. However, the narrow channel of ZSM-5 brought quite a large difference of the molecular diffusion energy barriers for model compounds in ZSM-5. Experimental results proved that ZSM-5 was a good candidate zeolite to selectively catalytic crack olefins in FCC gasoline to produce butene and propylene.
出处
《石油学报（石油加工）》
EI
CAS
CSCD
北大核心
2007年第1期41-45,共5页
Acta Petrolei Sinica(Petroleum Processing Section)
基金
国家重点基础研究发展规划‘973’项目(2004CB719505)资助
关键词
FCC汽油
扩散
分子筛
分子模拟
FCC gasoline
diffusion
zeolite
molecular simulation
