Liquid load point determination in a reactive distillation packing by X‐ray tomography

Abstract

In this paper, we report on the use of X-ray tomography to determine the liquid load point in 0.1 m diameter modular catalytic distillation packings Katapak-SP11 and Katapak-SP12. The liquid load point corresponds to the overall packed bed liquid load above which there is an increment in the liquid flowing outside the catalytic baskets and the catalytic baskets themselves are saturated with liquid. From tomographic images, we show that several factors affect the wetting and filling of catalytic baskets. The complex hybrid structure of catalytic packings influences the liquid distribution inside the elements. The liquid preferentially fills the external catalytic baskets because they receive the liquid not only from the packing element situated above but also from the wall wipers. Moreover, liquid hold-up inside a catalytic basket section depends significantly on the vertical position in the packing element and on the position of the packing in the column packed bed. The counter-current gas flow speeds up the process of liquid filling of the baskets, also for low liquid loads. The non-uniform distribution of liquid in catalytic basket which is observed experimentally makes the identification of a unique liquid load point not straightforward.Nous donnons dans ce document un compte rendu de l'utilisation de la tomographieà rayon X dans la détermination du point de chargement du liquide dans leséléments modulaires de distillation catalytiques de 0,1 m de diamètre Katapak-SP11 et Katapak-SP12. Le point de chargement du liquide correspondà la charge liquide d'un lit fixe rempli au-dessus de laquelle il y a un incrément dans l'écoulement du liquide hors des paniers catalytiques et les paniers catalytiques sont eux-mêmes saturés de liquide. Nous démontrons,à partir des images tomographiques, que plusieurs facteurs affectent la fluidisation et le remplissage des paniers catalytiques. La structure hybride complexe deséléments de lit catalytique influence la distribution du liquideà l'intérieur deséléments. Le liquide remplit préférentiellement les paniers catalytiques externes parce qu'ils reçoivent le liquide non seulement de l'élément du lit se trouvant au-dessus maiségalement des pales raclantes des parois. En outre, la retenue de liquideà l'intérieur d'une section du panier catalytique dépend de manière significative de la position verticale dans l'élément du lit et de la position de l'élément dans le lit rempli. L'écoulement de gazà contre courant accélère le processus du remplissage du liquide dans les paniers, aussi pour les charges liquides faibles. La distribution non uniforme du liquide dans le panier catalytique qui est observée expérimentalement fait que l'identification d'un point de chargement unique n'est pas si simple.

Enzymatic Reactive Distillation: Kinetic Resolution of rac-2-Pentanol with Biocatalytic Coatings on Structured Packings

“…However, it is unknown for the KATAPAK-SP-like structure which is custom-made. Nevertheless, the KATAPAK-like packing is fairly similar to the packing KATAPAK-SP11 so that equal surface areas were assumed and taken from Aferka et al 16 Some key data on the structure and the materials of the column internals are given in Table 2.…”

Tomographic measurement of liquid hold up and effective interfacial area distributions in a column packed with high performance structured packings

“…Hydrodynamic quantities such as liquid hold up and gas-liquid interfacial area have thus to be measured at a very small scale. X-ray tomography has been shown to be an efficient non-intrusive tool to see inside and to adequately image the liquid and vapor flow distribution in packed columns (Schmit et al, 2001Green et al, 2007;Toye et al, 2005;Aferka et al, 2007Aferka et al, , 2010aAferka et al, , 2010bViva et al, 2010). Green et al (2007) used X-ray CT to determine the effective wetted area and local liquid hold up for an air-water contactor containing structured packings, and especially traditional Mellapak 250.Y.…”

Development of an Integrated Reaction–Distillation Process for the Production of Methylal

“…For the final design, the minimum required catalyst mass was doubled to compensate model uncertainties. The column diameter was fixed so that a reasonable liquid load in the reactive packings is achieved . The design of the height of the reactive zone was subsequently calculated from the determined mass of catalyst assuming a catalyst volume fraction of ϵ K‑SP 11 = 0.4 for the packing .…”

“…The column diameter was fixed so that a reasonable liquid load in the reactive packings is achieved. 42 The design of the height of the reactive zone was subsequently calculated from the determined mass of catalyst assuming a catalyst volume fraction of ϵ K-SP 11 = 0.4 for the packing. 38 With the assumption of NTSM = 2 for Katapak-SP 11 packing at the industrial scale, 38 the height of the reactive section was determined to be four theoretical reactive stages, or 2 m. These four stages were integrated into the column, and two additional theoretical stages were added below and above the reactive section to ensure the separation of methylal from the liquid phase above the reactive section and the vapor side draw.…”