Gas–Solid Flow Hydrodynamics of an Industrial Scale Catalyst Lift Engager

Abstract

The catalyst lift engager is a key unit that circulates catalyst between the reactor and regenerator sections of a continuous catalytic reformer (CCR) in oil refineries. Reliable prediction of the gas-solid flow hydrodynamics in this complex geometry is important for understanding and optimising the catalyst circulation system. This study characterises the hydrodynamics of an industrial-scale catalyst lift engager using a granular Eulerian CFD model.

Geldart D particle flow was simulated using the kinetic theory of granular flow (KTGF)-based approach, with the effects of various model parameters including drag models and frictional pressure closure models investigated. The KTGF-based frictional pressure model was found to produce inconsistent results with increasing catalyst velocity and volume fraction along the lift line. In contrast, the Johnson and Jackson frictional pressure model proved superior, particularly for complex flow domains containing both dilute and dense phase flows. Lower lift gas velocity led to large-scale fluctuations in the outlet mass flow rate, which has implications for stable operation. Simulation results showed reasonable qualitative agreement with previously reported riser flow studies. The study concludes that the Johnson and Jackson frictional pressure model should be preferred over the KTGF model for complex flow domains encountered in industrial catalyst lift engagers.

@article{shah2010gas,
  title         = {Gas--Solid Flow Hydrodynamics of an Industrial Scale Catalyst Lift Engager},
  author        = {Shah, Milinkumar T and Mayne, Jeff and Utikar, Ranjeet P and Tade, Moses O
                  and Pareek, Vishnu K},
  year          = 2010,
  journal       = {Chemical Engineering Journal},
  publisher     = {Elsevier},
  volume        = 159,
  number        = {1--3},
  pages         = {138--148},
  doi           = {10.1016/j.cej.2010.01.055}
}