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

Abstract

The objective of this work is the computational fluid dynamics (CFD)-based optimization of a gas–liquid two-phase NO_x 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 NO_x removal.

Keywords:

• CFD modeling
• Fenton reaction
• Kinetic modeling
• Multiphase system
• NO_x removal
• Particle tracing

Additional information

Funding

The project was supported by National Key Research and Development Program of China (2018YFB0605101), Key Project Natural Science Foundation of Tianjin (18JCZDJC39800), The project of science and technology of Tianjin (18ZXSZSF00040, 18KPXMSF00080, 18PTZWHZ00010) and The project of science and technology of Tangshan (18130211A). Authors thank the financial support of Széchenyi 2020 under the EFOP-3.6.1-16-2016-00015.