Mathematical modeling of a slurry reactor for DME direct synthesis from syngas

In this paper, an axial dispersion mathematical model is developed to simulate a three-phase slurry bubble column reactor for direct synthesis of dimethyl ether (DME) from syngas. This large-scale reactor is modeled using mass and energy balances, catalyst sedimentation and single-bubble as well as two-bubbles class flow hydrodynamics. A comparison between the two hydrodynamic models through pilot plant experimental data from the literature shows that heterogeneous two-bubbles flow model is in better agreement with the experimental data than homogeneous single-bubble gas flow model. Also, by investigating the heterogeneous gas flow and axial dispersion model for small bubbles as well as the large bubbles and slurry (i.e. including paraffins and the catalyst) phase, the temperature profile along the reactor is obtained. A comparison between isothermal and non-isothermal reactors reveals no obvious performance difference between them. The optimum values of reactor diameter and height were obtained at 7 m and 50 m, respectively. The effects of operating variables on the axial catalyst distribution, DME productivity and CO conversion are also investigated in this research.