Performance evaluation on new catalyst for producing aromatics fromliquefied petroleum gas

Key words:  liquefied petroleum gas  aromatization  catalyst  characterization  evaluation

Abstract:

An aromatization catalyst for liquefied petroleum gas(LPG) was prepared by impregnating Zn or Zn-Al oxides onto HZSM-5 zeolite, and was characterized by X-ray diffraction ( XRD) and infrared ray (IR). The effects of different metals, metal content and both metal on modified HZSM-5 zeolite catalyst were investigated by a 100 mL packed bed reactor at 510 X., mass space velocity of 0.25 h'1 and system pressure of 0. 1 MPa. The characteristic results demonstrate that the number of Bronsted acid sites decreased and the number of Lewis acid sites increased markedly, and the new aromatization active sites were formed. The experimental results indicate that compared with HZSM-5，the yield of aromatics for LPG aromatization over Zn/HZSM-5 catalyst increased by 22%，and the stabilization of catalyst was improved obviously. The Zn-Ai/HZSM-5 catalyst could not only increase the yield of aromatics for LPG aromatization, but also reduce the deactivation of the catalyst. When the content of Zn element and A1 element were in the range of 2.0% -4.0% , 2.0% -3.0% in Zn-Al/HZSM-5，respectively, the catalyst performed good activity and high stabilization.