CFD-based assessment of steady-state multiplicity in a gas-solid vortex reactor for oxidative coupling of methane

Commercially viable OCM will depend largely on process intensification, i.e., innovative reactor and process design. Such an OCM reactor should have two characteristics: limited species backmixing and sufficient thermal backmixing. Short residence times with a narrow distribution have indicated that a GSVR exhibits at least the first of these two desired characteristics. Whether it also exhibits the second is less straightforward to verify. Our reactive CFD framework catchyFOAM is used to perform adiabatic simulations of a GSVR for OCM for a wide range of inlet temperatures (648 K – 1198 K), while fixing the inlet composition (CH4:O2 = 4), mass flow rate (3.6 10 −3kg s −1), catalyst mass (12 g) and total pressure (1, 2, 5 bar). This allowed to construct CFD-based bifurcation diagrams of the outlet temperature, conversions and selectivities versus inlet temperature. A wide window of steady-state multiplicity was simulated at 5 bar, with on the ignited branch a CH 4conversion of 37% and C 2selectivity of 72%, for an inlet temperature of only 698 K. This indicates that also the second criterion for an intensified OCM reactor, i.e., to allow steady-state multiplicity, can be met in a GSVR.