EFFECTS OF PHOSPHORUS MODIFICATION ON ACIDITY OF Pt/HZSM-5 CATALYST AND ITS HYDROISOMERIZATION PERFORMANCE

Abstract

Abstract: The Pt-P/HZSM-5 isomerization catalysts were prepared by incipient wetness impregnation and characterized by N2 adsorption-desorption, XRD, NH3-TPD, and Py-IR. The isomerization performance of the prepared catalysts was evaluated in a continuous fixed bed reactor. The results showed that the addition of a small amount of phosphorus can significantly change the acid amount and acid strength distribution of Pt/HZSM-5. The strong acid sites decrease and the weak acid and Br?nsted acid sites increase. Pt-P/HZSM-5 catalysts significantly inhibit the cracking reaction and improve the isomerization rate and dimethylbutane selectivity. At 1.5 MPa, 280 ℃ and H2/oil volume ratio of 500, LHSV of 1 h-1, the Pt-P/HZSM-5 catalyst with 1% P and 0.4% Pt gives the best isomerization results of 75.78% n-hexane conversion rate, 75.36% isomerization rate, 3.69% cracking rate and 6.65% dimethylbutane selectivity.

Key words: Pt-P/HZSM-5, diammonium phosphate, hexane, isomerization

CLC Number:

References

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