Abstract:

A axisymmetric fluid solid coupled model of coke tower containing the equations of momentum and mass transfer of porous media, as well as the equivalent fluid model is developed in this paper, which is used to simulate both the traditional and a new cooling method by mixing spray with vapor in big flow unit of delayed coking. In the paper, the calculated transient temperature field of coke drum with shell model applied in pure vapor has been validated by the measured data. Meanwhile, it predicts transient temperature field of coke drum in new way of cooling, illustrates the impacts of the mass fraction of liquid water on the effects of coke drum cooling, and quantitative evaluated the vapor saving and economic cost of new process. The research results indicates that the cooling effect is first quickly improved then slow down and final restrained with the increase of content of liquid water, the optimum fraction is 0.8 to realize the best cooling effect. The article give the vapor saving percentage and annual saving cost at the liquid water fraction from 0.4 to 0.9in the condition that the pressure is 0.3MPa and the mass flow is 7.5t/h. The conclusions will be helpful for optimizing process parameters in delayed coking.

Key words: delayed coking, mixing, spray coke cooling, porous media, numerical simulation