(174ab) Quantification and Pseudo-3D Modelling of Liquid Holdup and Maldistribution in a Trickle Bed Reactor with Validation Using Gamma-Ray Computed Tomography

Trickle bed reactors, in which gas and liquid phase reactants flow in downward direction over a bed of solid catalyst particles, have quite versatile applications such as oxidation reactions, petroleum processing, hydrogenation reactions, esterification, F-T synthesis etc. Phase distributions and holdups in multiphase flow reactors can affect many other design parameters such as wetting efficiency, heat and mass transfer coefficients etc. The phase holdup in the bed also controls the phase residence time and conversion of the reactants. It is therefore essential to understand how gas/liquid distribute at different axial levels and how gas/liquid holdup varies along such as (1) column diameter, particle size and shape, (2) operating conditions like gas/liquid flowrates, (3) physical and chemical properties of fluids.
Proper and highly accurate investigations of phase distributions and holdups are imperative for the design and diagnoses of multiphase flow reactors. Gamma-ray computed tomography is a non-invasive technique that provides the cross-sectional images at different axial levels by rotating the gamma source and its detectors around the object. It can visualize and quantify the phase distributions and holdup profiles for multiphase flow reactors which cannot be measured by other techniques.
In this study, the experimental work on the investigation of the phase distribution and holdup of porous quadrilobe catalyst in a TBR are finished using advanced Gamma-ray CT. The quantification and mapping of the maldistribution based on the dynamic liquid holdup are achieved in this work. A pseudo-3D phenomenological model is proposed in this work.