Enhancement of the acetylene and ethylene yields from ethane by partially decoupling the oxidation and pyrolysis reactions

The ethane contained in wet shale gas is usually used to produce ethylene through the steam cracking process. In parallel, the partial oxidation (PDX) of methane is the most important method to produce acetylene. In this paper, the feasibility of the PDX process of ethane was first explored. The reaction pathway analysis showed that the exothermal oxidation and endothermic pyrolysis reactions were highly coupled, which limited the yield of C-2 species (C2H2 + C2H4). To overcome this problem, a new process named partially decoupling process (PDP) was proposed to physically separate the heat supply and pyrolysis reactions in a jet-in-cross-flow (JICF) reactor. The computational fluid dynamics (CFD) coupled with a detailed reaction mechanism, the modified Gill 3.0, was applied to simulate the complex interaction between turbulent mixing and reactions. The results showed that a high combined yield of ethylene and acetylene (69%) could be obtained. The operating and reactor structural parameters were further optimized based on the CFD simulations. The maximum yield of C-2 products was found less sensitive to the mixing in the ethane PDP than in the methane PDP, making it easier to scale up the reactor for the ethane PDP.