Simulation of the decoking of an ethane cracker with a steam/air mixture

A combined furnace and reactor calculation is performed for the simulation of the decoking of an ethane cracker with a steam/air mixture. Different gas–solid reaction/diffusion models with a corresponding texture model describing the solid phase changes during the decoking operation are combined with kinetics for the decoking by combustion and gasification, determined based on experimental data [Heynderickx, G.J., Schools, E.M., Marin, G.B., 2005. Coke combustion and gasification kinetics in ethane steam crackers. A.I.Ch.E. Journal 51 (5), 1414–1428]. By comparing the calculated coil outlet temperatures and the calculated partial pressures of carbon dioxide at the coil outlet with the measured values in an industrial unit, the need for a general gas–solid reaction/diffusion model and the corresponding decoking kinetics is confirmed. The decoking time for an industrial unit is simulated adequately.