Packed bed systems

EXAMPLE 19.1 DESIGN OF A SINGLE ADIABATIC PACKED BED SYSTEM... 

We shall first discuss the dispersion and backmixing models which adequately characterize flow in tubular and packed-bed systems then we shall consider combined models which are used for more complex situations. In connection with the various applications, the direct use of the age-distribution function for linear kinetics will also be illustrated. 

Allows for versatihty in the treatment train (can be used as a filter or as a packed-bed system). 

Hlavacek (1970) has shown that radiation between the solid catalyst and gas can significantly affect the temperature dynamics in packed bed systems operating in excess of 673 K. Since most packed bed systems usually operate well below these conditions, radiation terms are not explicitly included in the model. However, their effect can to some degree be accounted for in the overall heat transfer coefficients.4... 

Encapsulation and Suspension. In this case, encapsulated spheroids of hepatocytes are contacted with blood in fluidized-bed, spouted-bed, and/or packed-bed systems. The mass transfer resistance should be high with encapsulated cells. However, the use of a suspension would lead to excessive shear forces being exerted on the cells. 

Diffusion Models for MTZ Length Correlation. Figure 3 shows the various diffusive resistances likely to occur in the packed bed systems investigated, and the manner in which they are... 

Very low pressure drop in single- and two-phase flow, one to two orders of magnitude lower than in conventional packed-bed systems... 

The Eulerian continuum approach, based on a continuum assumption of phases, provides a field description of the dynamics of each phase. The Lagrangian trajectory approach, from the study of motions of individual particles, is able to yield historical trajectories of the particles. The kinetic theory modeling for interparticle collisions, extended from the kinetic theory of gases, can be applied to dense suspension systems where the transport in the particle phase is dominated by interparticle collisions. The Ergun equation provides important flow relationships, which are useful not only for packed bed systems, but also for some situations in fluidized bed systems. 

Both enzymes were immobilized on beads (125-315 tm) and serially used in enzyme reactors either as packed beds or as expanded beds. Again detection was based on amperometric H2O2 detection. Co-reagents, such as NADH and NH3, were added to the carrier. The expanded bed reactors showed a lower sensitivity and longer response times compared to the packed bed system. However, the risk of clogging due to sample constituents... 

Secondary clean-up using packed bed systems to remove metal carbonyls, mercury and trace acid gas ... 

Computerisation can help in keeping cultivation conditions near ideal throughout the fermentation without manual intervention. It is difficult however to control pH as there is no reliable way of measuring the pH in the solid matrix. An automated packed bed system fitted with inlet and exhaust gas analysers can be used to precisely control cultivation atmospheres to give optimal enzyme yields. 

Start a blank simulation with general metric units. At the bottom of the flowsheet page click on the tab labeled columns. Use the column simulator RADFRAC. Draw a flowsheet of a single colunm with one feed, a liquid distillate product (red arrow), and a liquid bottoms product. (This is the most common configuration for distillation columns.) Click on the arrow to the right of the RADFRAC button to see alternative sketches of the column. Do not use a packed bed system The screen should look similar to Figure 4-Al. 

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