| In order to fulfill the standard of low sulfur and ultra-low sulfur gasoline,the hydrodesulfurization of FCC light gasoline is more and more important.The hydrodesulfurization selectivity of FCC light gasoline may be remarkably favored by pre-aromatization of the high level olefms in the light range gasoline.Thus,the aromatization of FCC light gasoline was studied herein with a nano-sized HZSM-5 zeolitic catalyst.The following main results are obtained:(1) The influence of reaction conditions and impurities in feedstock on the aromatization of FCC light gasoline(≤85℃) over nano-sized ZSM-5 catalyst is investigated.Results show that,nano-sized ZSM-5 catalyst exhibits wonderful performance of aromatization.But the gasoline yield of the reaction is quite low,and the deactivation of catalyst is very serious due primarily to the thermal oligomerization of diene in FCC light gasoline feedstock.These problems make the aromatization of FCC light gasoline highly challengeable in the course of commercialization.(2) The co-feed of C4 liquefied petroleum gas(C4 LPG) with the FCC light gasoline (≤85℃) seems to be a good method to compensate the gasoline yield of the aromatization of FCC light gasoline.(3) The combinational use of Nano-sized ZSM-5 catalyst with a Al2O3 supported hydrodesulfurization catalyst(DLS-1) at low temperature is another clue to FCC light gasoline(≤85℃) processing.Under the conditions of 280℃,1.6 MPa,V(H2) = 13 ml/min, WHSV=1.5 h-1,the weight proportion of nano-sized HZSM-5 catalyst to hydrodesulfurization catalyst DLS-1 = 2,the loading of nano-sized HZSM-5 catalyst over the hydrodesulfurization catalyst DLS-1 gives 60%desulfurization rate and 20%olefm saturation rate.This hydrodesulfurization selectivity of the combined catalysts is better than the DLS-1 alone which results in 60%olefin loss at the desulfurization rate of about 80%.The only problem is that under such a low temperature the aromatization of FCC light gasoline over the zeolitic catalyst was not seen.
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