CONVERSION OF C₄-FRACTION OF LIQUEFIED PETROLEUM GAS ON ZEOLITECONTAINING CATALYST MODIFIED WITH CHROMIUM AND PHOSPHORUS

A zeolite-containing catalyst modified with chromium and phosphorus additives has been developed. The technological conditions of its optimal activity in the dehydrogenation reaction and oligomerization of the C₄ fraction of liquefied petroleum gas to produce gasoline components are determined.
A study of the physicochemical properties of a 5% Cr/Al₂O₃+ HZSM catalyst promoted with 5% phosphoric acid was carried out. The structure of the catalyst was studied by electron microscopy in combination with microdiffraction. The reflections of HZSM and Al₂O₃ were detected using the X-ray diffraction method. It was also shown by the EPR method that the PFK-9 catalyst is characterized by a narrow singlet symmetrical EPR signal with a g-factor of 1.96 and a width ∆Н=60 Gauss against the background of a broad signal with ∆Н=1000 Gauss. The narrow EPR signal is due to Cr⁵⁺ ions in the matrix and HZSM zeolite. The intensity of the Cr⁵⁺ signal in the PFK-9 catalyst is 205 conventional units. The specific surface area of the catalyst is 176,5 m²/g, the pore volume is 0,137 ml/g.
The catalyst at contact with C₄-alkanes (400-600°C, P=0,1 MPa) makes dehydrogenation with reception olefins with the subsequent them oligomerisetion. A study of the conversion of the C₄ fraction of LPG on the PFK-9 catalyst was also carried out in the presence of water vapor.
The yield of C₅-C10-hydrocarbons depending on technological conditions fluctuates within 40-50%, at the degree of conversion raw material 80-90%.

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