Computational insights on intensification of hydrodenitrogenation in a trickle bed reactor using periodic flow modulation

Trickle bed reactors (TBRs) are widely used in petroleum industries, which are subjected to stringent environ-mental laws. Hydrodenitrogenation (HDN), a crucial process for nitrogen removal employed in crude oil processing, is typically carried out in steady state TBRs. Acquainted with this operation, researchers are focused on exploring the efficacy of flow modulation in TBRs for improved reaction conversion. A CFD model of a hydro treating reactor is used in this work to examine potential benefits of periodic operation for a HDN reaction. Results of continuous flow were compared with time averaged conversions for slow and fast modes of on-off and min-max operations having different split ratios. All flow modulated cases proved to be beneficial than steady state operation with respect to enhanced time averaged conversion. However, this enhancement deteriorated with increase in cycle time for slow mode of operation. Additionally, this was associated with substantial undulations in overall pressure drop, which is detrimental to process safety. Nonetheless, fast mode of on-off and min-max operations at low split ratio resulted in maximum improvement of about 47% and 35%, respectively, which revealed the efficacy of fast mode flow modulation in achieving maximum conversion with lower pressure drop undulations.