Abstract: Using FLUENT software to construct one dimensional model and two dimensional models of ethane and propane mixture cracking reaction, the effects of radial flow rate, temperature, concentration distribution and free radical concentration distribution on the mixed cracking process of ethane and propane were simulated respectively. The results showed that the transfer process was coupled with the cracking process, and the cracking temperature of alkanes was decreased by radial diffusion. The concentrations of CH₄ and C₂H₄ in 2-D simulation were higher than those in 1-D simulation, while the concentrations of H₂, C₂H₆ and C₃H₆ were slightly lower. The mixed cracking of ethane and propane was mainly initiated by the chain initiation of propane, and both ethane and propane took part in the chain propagation process. During ethane and propane mixture cracking process, there were free radicals H·, CH₃·, C₂H₅·, i-C₃H₇· and n-C₃H₇·in the system. The concentrations of free radicals C₂H₅·, i-C₃H₇· and n-C₃H₇· need to be accumulated before olefin could be formed. Ethylene was mainly generated by C₂H₅· and n-C₃H₇· and propylene was mainly generated by i-C₃H₇· and n-C₃H₇·.

Key words: ethane, propane, mixed cracking, reaction mechanism, 2-D simulation