Rate‐based‐Modellierung von CO2‐Absorptionskolonnen mit Anstaupackungen

The efficiency of columns for fluid separation can be increased by the application of sandwich packings. During the operation, different load‐dependent regimes with peculiar separation performance arise. In order to account for the effects of the individual flow regimes in a single model, both separation performance measurements and tomographic imaging are applied. A rate‐based model is presented, which takes the heterogeneous regimes in sandwich packings into account by means of appropriate correlations. The model is tested with experimental data for CO₂ absorption.     

Systems with Structured Packing: Fluid‐Dynamics and Liquid‐Solid Mass Transfer

Structured packings are often incorporated in industrial equipment as a way of enhancing the efficiency or as support of catalysts and microorganisms. They may operate in single‐, two‐ or three‐phase flow and natural convection can be present. The fluid‐dynamic and mass transfer behavior of spaced and stacked structured packings for these conditions is systematically analyzed.     

Einfluss der Wechselwirkung von Reaktion und Fluiddynamik auf das Verhalten von Strahlschlaufenreaktoren

Jet loop reactors are used as apparatus to facilitate chemical or biological reactions. This type of apparatus is characterized by an internal circulation flow, essentially driven by the injection of liquid. The nozzle can also be used to inject and disperse gas. The internal fluid dynamics and thus the reactor behavior is significantly determined by the introduced momentum and by the internal gas distribution. To describe the mutual influence of a gas-consuming reaction and the internal fluid dynamics, a simplified model based on a momentum balance and a material balance was used. From the exemplary calculations, a critical range for non-selective reactions and for fluid dynamic stability is given.     

Auslegung von Blasensäulen mithilfe von Compartmentmodellen

In bubble columns, the phenomena of mass and heat transfer as well as the reaction are closely linked to the complex fluid dynamics. Compartment modeling offers the opportunity to integrate these phenomena while enabling an axial and radial distribution with acceptable computing effort. This article includes methods for generating the compartment geometry and fluid dynamic parameters of this modeling approach, facilitating the opportunity to optimize an industrial bubble column.     

Liquid Holdup in Catalyst‐Containing Pockets of a Modular Catalytic Structured Packing

This paper introduces a simple, first principles‐based model describing the liquid holdup in the catalyst‐containing pockets of Katapak‐SP, a modular catalytic structured packing developed to allow a certain degree of flexibility with respect to the variation in reaction‐to‐separation requirements in a single unit. The basic requirement for the catalyst‐containing pockets in this respect is to be fully filled with flowing liquid which implies that the operating holdup is bound between the static holdup of the catalyst bed as the lower end, and that corresponding to the upper limit, the so‐called catalytic load point. The latter is the liquid load corresponding to the bed saturation point, indicating that excessive liquid will be retained, i.e., will remain in the separation part of the packing element and mix with the liquid leaving the catalyst‐filled pockets at the bottom of the element. Detailed knowledge of the liquid holdup as well as the pattern of the trickling flow is essential because it governs the performance of the reaction part and consequently the hybrid unit as a whole. Both glass and resin (an industrial catalyst) particles were used in conjunction with water and a binary water‐methanol mixture as working fluids. The model predictions for static holdup and the catalytic load agree well with the experiments.     

Imaging of Fluid Dynamics in a Structured Packing Using X‐ray Computed Tomography

For the investigation of fluid dynamics from computed tomography (CT) images, an evaluation method was developed that enables data acquisition directly from the recorded CT images. A segmentation algorithm was implemented in Matlab to assign every component a specific gray value. A comparison of weight experiments with CT scans and following segmentation demonstrates the good accuracy of this method. The liquid holdup in different Mellapak 500.Y packings was determined through CT measurements and compared to predictive correlations from the literature. Three‐dimensional visualizations of short packing sections enable an evaluation of the liquid distribution and the flow morphology of the liquid in the packing. The common assumption of an evenly wetted packing surface with a constant liquid film thickness could not be proved.     

CFD‐Simulation und LDA‐Messung der Strömungsvorgänge beim Fluidphasenresonanzmischen

The principle of fluid phase resonance mixing is to apply harmonic oscillating pressure via a gas cushion on a liquid phase in a vessel and thus to cause the liquid phase to start oscillating. This principle is simulated as an unsteady flow of two separate phases with open source CFD software OpenFOAM and the results are verified with measurements by Laser Doppler Anemometry.     

The effect of fly ash on fluid dynamics of CO2 scrubber in coal-fired power plant

Uncaptured fly ash and/or suspended solids from wet flue gas desulfurization (WFGD) scrubbing solutions are one of several factors that will influence the performance and robustness of carbon dioxide capture systems in coal-fired power plants which will be installed prior to the exhaust stack. In this study, a 100 mm ID packed column scrubber was tested with different concentrations of ash in various chemical solutions to evaluate the influence of solids on the fluid dynamics of the packing material. Data reported here are collected from three solutions including water, 30 wt% MEA (monoethanolamine), and 20 wt% potassium carbonate. The packing selected for this study was a 16 mm polypropylene pall rings. Compressed air was used to simulate flue gas at near ambient temperature and pressure.     

Schnelle und präzise Bestimmung des Gesamtglucosinolatgehaltes von Rapssamen-Vergleich der Röntgenfluoreszenzanalyse mit Gaschromatographie und Hochdruckflüssigkeitschromatographie

Rapid and Precise Determination of Total Glucosinolate Content in Rapeseed – Comparison of X-Ray Fluorescence Spectroscopy with Gaschromatography and High-Performance-Liquid-Chromatography The introduction of oilseed-rape cultivars poor in glucosinolates within the EG requires methods which allow a separation of the yield batches by the glucosinolate content. By means of the indirect determination of the glucosinolate content by X-ray-spectroscopy a method is introduced that produces a high correlation with conventional procedures (r² = 99% for GC-reference samples, r² = 92% for GC single data, r² = 96% for HPLC single data; deviations from average values: GC-reference samples 1.3%; single analyses of GC and HPLC 7.4 respectively 3.1%) and that needs only 4 minutes for one complete determination and is easily to perform.     

Untersuchung von lokalen Schichtdickenverteilungen in Fluiden mithilfe der Nahinfrarot‐Bildanalyse

An online image analysis method to determine the film thickness in fluids by use of pulsed near infrared LEDs and an NIR camera was developed. This technique offers the possibility to monitor moving fluid layers. In this work the possibilities and limits of the used apparatus are demonstrated with the application example of measurement of the fluid film thickness distribution of water and glycerol in a falling film.     

Methode zur Untersuchung der Partikelbewegung in diskontinuierlich und kontinuierlich arbeitenden Wirbelschichten

A novel method, the magnetic monitoring was used for particle tracking in batch and continuous fluidized beds. By means of the magnetic monitoring system the spatial coordinates x, y and z and the orientation of the magnetic marked particle are measured. This allows calculation of the particle velocity, the particle acceleration and also the forces and energies acting on the particles both for translation and for the rotation. In the present work, the movement characteristics of the particle were determined. Moreover, the influence of different apparatus and operating parameters on the movement characteristics were investigated.