Simulation of Operating Condition Optimization of Naphtha Steam Pyrolysis for Improving Olefin Yields

A two-dimensional mathematical model was used to simulate Daqing naphtha steam pyrolysis and analyze the effect of operation conditions on ethylene,propylene,butadiene yields and the sum yield of olefins.In the simulation,the steam/hydrocarbon mass ratio was adjusted with fixed molar flow rate of naphtha and steam.The orthogonal experimental design method was used to prove no interaction of operation conditions and the reliability of the simulation results.The results showed that the optimal operating conditions were never the same for different goals.The optimal temperature was 1143,1103,1133and 1143Kfor enhancement of ethylene,propylene,butadiene yields and total olefin yield,respectively.Cracking depth depended on the pyrolysis temperature.As naphtha didn't reach the maximum cracking depth,the effects of residence time and steam/hydrocarbon mass ratio were more.On the contrary,the effects of residence time and steam/hydrocarbon mass ratio were less.Therefore,the cracking depth could be enhanced by temperature rising and shortening residence time,while the effect of steam/hydrocarbon mass ratio was least.