Abstract: The difference of CH4 yields in catalytic cracking and thermal cracking of naphtha were investigated. The influence of operating parameters, micro-activity of catalyst and hydrocarbon structures on the CH4 yields and selectivities was explored. The results indicate that catalytic cracking reaction has a larger contribution to methane formation in range of 600℃ to 700℃, in which the stronger Br?nsted acidic sites play a key role. Paraffinic hydrocarbons are apt to produce more methane and the protolytic cracking tend to take place on C–C bond or C–H bond adjacent to C2 carbon atom in the carbon chain. Among the factors, the cracking temperature and reaction time are the most important. In order to make balance between conversion of feed and CH4 selectivity, the optimized measures of suitable reaction temperature, high catalyst-to-oil ratio and short residence time are proposed.

Key words: naphtha, catalytic cracking, methane, operating parameter, catalyst