Optimization of a Fenton-based gas–liquid two-phase reactor for NOx removal

The objective of this work is the computational fluid dynamics (CFD)-based optimization of a gas–liquid two-phase NOx removal absorption vessel. One of the main effectors on the efficiency in a gas–fluid system is the construction of the inlet gas distributor. The optimal solution should provide homogeneous gas distribution in the vessel leading to better operation. Twenty-four different geometries with 8 nozzle number (1, 3, 5, 4, 9, 29, 37, and 61), and 3 inlet areas were drawn: 1.2e-4 m2 (100%) and 0% and 150% of the original area was simulated in a CFD environment. The geometries were evaluated based on the analysis of the gas volume fractions, well-mixed areas, particle trajectories, and outlet concentrations. The application of case 8 (with 29 inlet nozzles in non-uniform construction) and case 4 (with 61 uniform diameter nozzles) also exceeds the operation of the reference case and can be used for the improvement of existing construction. Based on the different evaluation criterion case 4 was chosen as the best solution, which provides at least 10% removal efficiency increase. With the homogeneous gas distribution, the phase contact within the vessel can be intensified, which will lead to more efficient NOx removal.