Kinetic modeling of the hydrotreatment of light cycle oil/diesel
MetadataShow full item record
A rigorous kinetic model of hydrodesulfurization (HDS) of complex mixtures such as light cycle oil (LCO) or diesel has been developed. An experimental setup was constructed to investigate the hydrotreatment of complex mixtures. The hydrodesulfurization of LCO on a commercial CoMo/Al2O3 (IMP) catalyst was investigated in a Robinson Mahoney perfectly mixed flow stationary basket reactor. An experimental investigation of the HDS of the dibenzothiophene (DBT) and substituted dibenzothiophenes in the LCO was carried out at temperatures between 290 and 330°C, space time for dibenzothiophene (W/F0 DBT) between 1000 and 6500 kgcat-h/kmol, and H2/HC molar ratio constant of 2.8. To avoid having to deal with a huge number of parameters in the model, a methodology based on structural contributions was applied. DENs and DENt are the denominators of the Hougen-Watson rate expressions for hydrodesulfurization of dibenzothiophene (DBT) and methyl-substituted dibenzothiophenes contained in the LCO. Both denominators comprise the concentration of all adsorbing species of the LCO multiplied by their adsorption equilibrium constants. The estimation of the denominators DENs and DENt was performed using the Levenberg-Marquardt algorithm and the results in terms of conversion for DBT, biphenyl and cyclohexylbenzene obtained in the hydrodesulfurization of the LCO. The evolution of DENs and DENt values with the composition was calculated for each LCO experiment. Structural contributions were taken from Vanrysselberghe and Froment for hydrogenolysis and hydrogenation of methyl-substituted dibenzothiophenes with a significant reduction in the number of parameters to be estimated in the HDS of the LCO. The multiplication factors, fsDBT, which are products of structural contributions for hydrogenolysis and hydrogenation of the mono- and dimethyl-dibenzothiophenes were also taken from Vanrysselberghe and Froment. These multiplication factors are based on experimental results with model components such as DBT, 4-Methyl dibenzothiophene and 4,6-Dimethyl dibenzothiophene. The results obtained in the modeling are in good agreement with the experimental data because the model reproduces very well the observed total conversions of DBT, conversions of DBT into biphenyl and conversions of DBT into cyclohexylbenzene as a function of temperature.
Castaneda-Lopez, Luis Carlos (2006). Kinetic modeling of the hydrotreatment of light cycle oil/diesel. Doctoral dissertation, Texas A&M University. Available electronically from