Improvement of a Kinetic Model for the Hydroconversion of an Atmospheric Residue in a Slurry Semi-batch Reactor

Previously, using a batch reactor, Nguyen et al. (2013) proposed a kinetic model for atmospheric residue hydroconversion wherein residue consumption rate depends on residue and dissolved hydrogen concentrations. In the present work, a new kinetic study was carried out in a semi-batch reactor at 420 and 430°C, total pressure of 15 MPa and different reaction times (0, 30, 60 and 120 min). Nguyen’s kinetic model was improved by introducing a hydrodesulfurization (HDS) reaction and modeling the gas flow dynamics at the outlet of the semi-batch reactor. A new set of kinetic parameters for atmospheric residue hydroconversion has been estimated using a nonlinear least-squares regression on the total mass of products and the dynamics of outlet gas flow. In comparison to Nguyen’s kinetic study performed in a batch reactor, the results of the present work do not show any mass transfer limitation for H2 from gas to liquid in the semi-batch reactor. A high value of kLa was obtained confirming the high efficiency of this kind of apparatus to estimate the kinetic parameters. Moreover, the differences found between the values of kinetic parameters obtained in both batch and semi-batch reactors were explained by a free radical kinetic model.