Numerical Simulation of Reaction Mechanism of Ethane Pyrolysis to Form Benzene and Styrene

Based on Materials Studio and Aspen Plus, the reaction mechanism of producing benzene and styrene from ethane steam heat lysis was investigated through the addition reaction of free radicals + alkenes or free radicals + alkynes to form large free radicals and then through the cyclization and dehydrogenation of large free radicals to form aromatic hydrocarbons. It was found the thermal cracking of ethane had 2 paths to form benzene and 1 path to form styrene. The 1st path to form benzene is that the product ethylene form C2H3• through a chain transfer, then C2H3• and ethylene additively react to form 1-C4H7•-4, which then reacts with ethylene to form C6H11•, and finally, benzene is produced by dehydrogenation and transfer of C6H11•. The 2nd path to form benzene is that acetylene is produced by dehydrogenation of C2H3•, and then acetylene reacts via two sub-paths to form 1,3-C4H5•-4, which is cyclized to form C6H9•, and finally, benzene is formed through dehydrogenation and transfer. The path to form styrene is that 1,3-C4H5•-4 and 1,3-butadiene are cyclized to form C8H11•, and styrene is finally formed through dehydrogenation and chain transfer. Comparative analysis with industrial data showed there were 3 cycles in the ethane thermal cracking reaction network. The simulation data were well consistent with the industrial production data.