Zone method based coupled simulation of industrial steam cracking furnaces

Abstract

Coupled furnace/reactor simulations were conducted to study industrial steam cracking furnaces. Zone method was performed for the firebox side, and the one-dimensional reactor model COILSIM1D was used for the reactor side. In the firebox model, the Hottel zone method model was used to calculate the radiation heat transfer. The flow and combustion model were based on the results of computational fluid dynamics (CFD) simulations. A comparison was made among the results of zone method simulation, CFD simulations, and industry or design data, and the zone method simulation results were found to agree well with industry or design data. For the secondary burners installed 0.6 m away from the primary burners, the tube skin temperature and heat flux obtained with the zone method were higher than that under CFD simulation in the middle of reactor tube, and after 15 m they were lower than that obtained with CFD simulation. The higher process gas temperature led to a faster increase in ethene yield using the zone method compared with CFD simulation, whereas a shift in the maximum propene yield upstream of the reactor occurred with the zone method. This method was suitable for real-time operation optimization of industrial steam cracking units.