Catalyst for aromatization of long-carbon chain alkane and preparation method and use thereof

A method for using a catalyst for aromatization of a long-carbon chain alkane, comprising:

• pretreating the catalyst for aromatization of a long-carbon chain alkane in a hydrogen atmosphere to reduce a platinum oxide to metallic platinum;
• and contacting the long-carbon chain alkane with the pretreated catalyst for aromatization to generate an aromatic hydrocarbon;
• wherein the long-carbon chain alkane is one or more of C5-C11 alkanes;
• wherein the aromatization temperature is 400° C-600° C., the weight hourly space velocity (WHSV) in the aromatization of the long-carbon chain alkane is 0.5-5h−1, and the molar ratio of hydrogen to the long-carbon chain alkane is (4-10):1;
• wherein the catalyst comprises an inorganic oxide carrier and a modified Pt/Kβ molecular sieve, wherein the modified Pt/Kβ molecular sieve comprises a modified Kβ molecular sieve and a platinum oxide loaded on the modified Kβ molecular sieve;
• and
• based on the weight of metallic platinum, the loading amount of the platinum oxide on the modified Kβ molecular sieve is 1%-3%;
• wherein the method for modifying the catalyst for aromatization of a long-carbon chain alkane comprises the following steps:
• step (1):
• sequentially subjecting a Naβ molecular sieve to ammonium ion-exchange and a first calcination to obtain an Hβ molecular sieve;
• step (2):
• subjecting the Hβ molecular sieve to a first hydrothermal treatment in an ammonium fluorosilicate aqueous solution and then a second calcination;
• and subjecting the obtained product to a second hydrothermal treatment in an alkaline salt solution to obtain a modified HP molecular sieve, wherein the alkaline salt comprises a carbonate, a bicarbonate and/or and an alkali;
• step (3):
• sequentially subjecting the modified Hβ molecular sieve to potassium ion-exchange and a third calcination to obtain a modified Kβ molecular sieve;
• step (4):
• impregnating the modified Kβ molecular sieve with a platinum-containing solution and then conducting a fourth calcination to obtain a modified Pt/Kβ molecular sieve;
• and
• step (5):
• mixing the modified Pt/Kβ molecular sieve as an active component with an inorganic oxide carrier, and then sequentially forming a uniform mixture, drying and calcining the mixture to obtain the catalyst for aromatization of a long-carbon chain alkane.