3 research outputs found

    Numerical Simulation of the Flue Gas and Process Side of Coking Furnaces

    No full text
    A numerical simulation for the flue gas and process sides of a coking furnace with floor gas burners was conducted. The computational fluid dynamics (CFD) approach was employed to simulate flow, combustion, and heat transfer in the furnace. The process-side conditions were calculated with a special program. The simulation provides detailed information about the flue gas velocity, temperature fields, and process conditions for this type of coking furnace. Good agreement is obtained between industrial measurement and simulated excess air coefficient, outlet temperature of flue gas, and outlet pressure on the process side. Moreover, the simulated results indicate that there are hot spots on the tubes, located at the height of 1.5–2.5 m. That is consistent with the actual phenomenon of industrial coking furnaces. To investigate the effect of furnace structure on physical field distribution and process-side conditions, a comparative simulation case with more wide spacing of burners to walls was conducted. Results indicate that the comparative case improves the uniformity of heat flux distribution, obviously, which is beneficial for the run length of coking furnaces

    Practical Model for the Induction Period of Heavy Oil during Thermal Reaction

    No full text
    The induction period is a significant concept for design and operation of the delayed coking process. To simplify the prediction of the induction period and make it applicable to operational analysis and real-time control of the thermal cracking process, a practical model for the induction period of heavy oil during thermal reaction, which is suitable for the non-isothermal reaction in the industrial conditions, was presented. The development of this model was based on the experimental data of five heavy oils. The model parameters were correlated with microcarbon residue (MCR) of heavy oil to improve the model universality. Furthermore, the validity of correlation between MCR and cracking kinetic parameters was proven. The model-predicted cracking conversion agrees well with the experimental values. The induction period model was employed to predict the induction period of two feedstocks reported in the literature. Results indicated that the induction period model is available for the thermal reaction of these heavy oils

    Kinetic Model for the Deep-Severity Thermal Reaction in the Coke Drum of Delayed Coking

    No full text
    The coke drum is the main reactor of the delayed coking process, in which the deep-severity thermal reaction of heavy oil takes place. To simulate the product distribution in this reactor, a kinetic model for the deep-severity thermal reaction was developed on the basis of the experimental data of a vacuum residuum in a microbatch reactor at 430–490 °C. The model-predicted results agree well with the experimental values. The ratio of the cracking gas/light distillate rate constant increases with the reaction temperature. Both the primary condensation/cracking rate constant and the secondary condensation/cracking rate constant increase with the reaction temperature. It means that the lower reaction temperature is advantageous to increase the distillate yield at the same reaction severity. Furthermore, a practical transformation method was presented to improve the suitability of this model. The comparison results indicated that this transformation method is available for the kinetic model in this research. Moreover, it can also be used for other lumping models similarly
    corecore