Gas flow simulation and modeling in ammonia oxidation processes

Revealing unfavourable conditions and designing solutions hereto do pay off in much lower consumption of raw materials supporting cost reduction programs in the nitric acid industry.

To discover such insufficient gas distribution in the reactor Umicore uses the numerical Computational Fluid Dynamics simulation (CFD).

The technical drawings of the reactor geometry are compiled in a three-dimensional computer graphics composed of four million network points.

These generate a volume mesh, a structured mesh exclusively composed of hexahedral cells.

The skewness, the orthogonally deviations of cell volumes (3D), is a measure of the asymmetry of the probability distribution of a real-valued random variable.

For the numerical implementation of the chemical reaction volume related heat sources are modelled in the catalyst pack incorporate local gas velocities, temperatures, as well as local gas densities. The source term can be defined with the local parameters for each single cell of the calculation grid.

This vectorial velocity and visualization of the reaction progress in the catalyst assembly provides the necessary information regarding the impact of the gas flow characteristic on the catalyst gauze performance. Umicore uses the numerical simulation to evaluate the improvement capability of technical installations such as guiding systems or perforated plates homogenizing the gas flow and load of the catalyst gauzes.

With such a measurement Umicore enables the highest possible utilization of the catalyst capability thus substantially reducing production costs.