No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
CFD Study of an Evaporative Trickle Bed Reactor
Abstract
A numerical study was carried out to investigate steady-state and transient phase distribution, evaporation, and thermal runaway in a large-scale high-pressure trickle bed reactor operating in the low interaction regime. The thermal inertia of the catalyst particles proved to be a significant contribution to the overall energy balance. A cooling recycle stream, containing reaction products and a fresh feed, was included via a closed loop calculation. It was found that, as expected, phase distribution in the catalyst bed had a substantial impact production rate; a faulty feed distribution system can cost approximately 20% in overall steady-state product conversion. Grid resolution effects were quantified and were found to have minimal impact on macroscopic measures. Also, most results were insensitive to the extent of the modeled domain and the commercial solver version. In the event that the cooling recycle stream is lost, the external reactor shell temperature can exceed its design intent. It was found that reducing the quantity of fresh reactant feed in this situation can dramatically reduce the potential for vessel damage.
ResearchGate has not been able to resolve any citations for this publication.
A model for the prediction of pressure drop and liquid holdup for trickling flow in packed bed reactors has been developed, based on the relative permeability concept. The relative permeabilities for gas and liquid as functions of corresponding phase saturations have been studied with 1300 newly measured data pairs of pressure drop and liquid holdup obtained for a wide range of commercially relevant operating conditions (including pressures up to 50 bar) as well as types of packing (both in terms of size and shape). The relative permeabilities are found to be solely the functions of corresponding phase saturations and it is shown that the functional form of the correlations developed, which are otherwise purely empirical by nature, has its roots in the physics of flow at the microscale level. The proposed model requires no prior experimental knowledge about the packed bed and is able to predict liquid holdup and pressure drop to within 5% and 20%, respectively, regardless of the type of packing or operating range investigated.