Experimentelle Untersuchungen zum Tropfenmitriss im Feedeinleitbereich von Destillationskolonnen

In this paper, experimental investigations on droplet separation in the feed inlet area of a distillation column are presented. For this purpose, the qualitative entrainment for different droplet separators of a distillation column was measured qualitatively in a pilot scale test rig. The results are discussed and evaluated in this paper with respect to their significance for the prevention of entrainment in the feed section. In addition, a short outlook on simulation-based determination of entrainment is given.     

Einfluß von thermophysikalischen Stoffdaten auf die Auslegung und den Betrieb von Destillationskolonnen

Influence of thermophysical data on the design and operation of distillation columns. It has become common practice in the petrochemical industry to utilize highly developed process simulators for the design of individual pieces of equipment or entire processes. Apart from actual model development, attention focusses on the calculation and use of efficient solution and converging algorithms in the development of such process simulators. Although frequent reference is made to the importance of the underlying material data in the literature and in practical applications there exist only scattered studies giving a suitable choice of the available substance data models and the sensitivity of the process variables to inaccuracy and uncertainty of the material data and the material data models. The present article illustrates the influence of material data (choice of model, sensitivity) for the example of the design and operation of distillation columns and several methods and recommendations are given for fast estimations. With the aid of appropriate examples, the influence of uncertainties in the underlying measured data and the phase equilibrium models on various process variables (plate number, reflux ratio, distillate and sump concentrations) is demonstrated.     

Reaktionen in Destillationskolonnen

Reactions in distillation columns . Reaction columns are an interesting alternative for numerous reactions, and they have often proved economically advantageous. The effects resulting from superposition of reaction and distillation are demonstrated for a few examples and the industrial exploitation of such a system is illustrated. In comparison to the processes in actual distillation columns the processes in reaction columns are extremely complex. It is therefore advantageous in industrial engineering design to have suitable mathematical models at hand. Control problems can be overcome by profile control or by dynamic detectors.     

Entwicklung eines Simulationsprogramms zum Scale-up von Hydrierreaktoren

Development of a simulation program for the scale-up of hydrogenation reactors. The scale-up of trickle-bed reactors to pilot and production scale has been difficult and necessitated considerable over-dimensioning. Therefore a simulation program based on a cell model has been developed in which the dimensions of a cell are directly related to the dimensions of the catalyst particles used. The kinetic equation is formulated with an effective rate coefficient as the only key parameter to be adjusted. With this coefficient the intrinsic rate coefficient, the mass transfer, and the incomplete catalyst particle wetting are considered. The model was applied to the hardening of fatty acids and the hydrogenation of fatty acid methyl esters in laboratory reactors. Comparison with experimental results of pilot and industrial scale is favourable. Thus the model can be used for the scale-up of trickle-bed reactors.     

Scale-up of fluidized-bed hydrodynamics

The scale-up of fluidized beds is not an exact science. However, using proven techniques based on experience and mathematical and/or design models can minimize risk and uncertainty when scaling up fluidized beds. Scaling, which maintains that certain dimensionless groups be matched in different sized units for hydrodynamic similarity to be achieved, is different than scale-up, and generally can not be applied to pilot plants used for scale-up. Scaling is typically more useful to be applied to cold model studies that can be used to improve the operation of an existing plant. Deep fluidized beds of Group A materials can cause significant gas bypassing leading to poor gas-solids contacting. Because commercial beds are generally deeper than beds used in pilot plants, care must be taken to ensure that beds that do not exhibit gas bypassing in smaller units, do not have gas bypassing in commercial systems.