Transformation of LPG into Aromatic Hydrocarbons and Hydrogen over Zeolite Catalysts

Abstract

A way to increase the value of LPG cut from petroleum feedstocks is its direct transformation to H2 and aromatic products; these aromatic products, BTX—essentially benzene (B), toluene (T), and C, -aromatics (X)—can be used as raw material for the petrochemical industry or as a blending mixture to enhance the octane number of gasoline. However, these transformations require high temperatures. Thermodynamic data show that the conversion of paraffins into aromatics is favored by increasing the length of the chain, and that aromatics are favored in relation to olefins (Table 1) [1,2]. Whereas aromatization of propane and higher paraffins can be carried out at temperatures lower than 500°C, transformation of ethane, and especially that of methane, requires much higher temperatures. This is experimentally supported by the transformation of various hydrocarbons, at constant temperature and space velocity. For instance, over H-[All-ZSM-5, butane and isobutane react four times faster than propane and 100 times faster than ethane [3].