A step toward the numerical simulation of catalytic hydrogenation of nitrobenzene in Taylor flow at practical conditions

A Qualitative Numerical Study on Catalytic Hydrogenation of Nitrobenzene in Gas-Liquid Taylor Flow with Detailed Reaction Mechanism

“…This assumption allows significant reduction of the computation time by decoupling hydrodynamic and mass transfer calculations. During the physical time span of 5 ms in this study, the produced aniline concentration in the previous numerical study [46] is less than 0.001% of nitrobenzene concentration. This agrees with the results from an experimental study [21] which shows that it takes about 50 min to completely convert half a liter of nitrobenzene.…”

“…With the current set-up, the bubble velocity (U B ) is not directly specified but dictated by the prescribed pressure drop across the unit cell (∆p UC ). Figure 5 shows the quasi-steady bubble shape and velocity field in a fixed (lower half) and a moving (upper half) reference frame corresponding to Case 2 in Woo et al [46]. Because of the short bubble length, there exists no axial region where the thickness of the liquid film is uniform.…”

“…The Taylor bubble consists of pure hydrogen gas and its volume is kept constant. Further details on the solution procedure upon the moving reference frame and estimation of physical properties are described in Woo et al [46].…”

“…The computational mesh in x and z directions consists of 200 × 37 uniform cells (∆x = ∆z = 0.03L ref ), including five non-uniform boundary layer cells (∆z = 0.003 − 0.013L ref ) near the upper wall. This is the same grid as used in our previous study [46], though cell sizes were given by factor 10 lower by mistake. Simulation results on a finer grid (∆x = ∆z = 0.02L ref ) show differences up to 0.8% and 4.6% for hydrodynamics and mass transfer, respectively [58].…”

“…DETCHEM TM (for DETailed CHEMistry) is a software package for modeling multiphase reactive flows designed to handle detailed reaction mechanisms. A recent study in the same context provides a useful step toward modeling catalytic gas-liquid Taylor flows at practically pertinent conditions [46]. The previous work is focused on the determination of physical properties and test conditions to set up practically applicable simulations with a simplified one-step global reaction mechanism ( C 6 H 5 NO 2 + 3H 2 → C 6 H 5 NH 2 + 2H 2 O ).…”