Slugging characteristics

The change in slugging characteristics of a given material due to increasing or decreasing operating pressure is difficult to confirm. 

Figure 15.6 Slugging characteristics for illustrative example, (a) Bed surface displacement, (b) Slugging frequencies.

Flow Regimes in Multiphase Reactors. Reactant contacting, product separations, rates of mass and heat transport, and ultimately reaction conversion and product yields are strong functions of the gas and Hquid flow patterns within the reactors. The nomenclature of commonly observed flow patterns or flow regimes reflects observed flow characteristics, ie, armular, bubbly, plug, slug, spray, stratified, and wavy. 

In this diagram the key features are A - Diffusion baffle this serves four roles. First to dissipate the velocity head, thereby improving the overall hydraulic characteristics of the separator. Next, to direct incoming flow downward and outward maximizing the use of the separator volume. Third, to reduce flow turbulence and to distribute the flow evenly over the separator s cross-sectional area. Finally, to isolate inlet turbulence from the rest of the separator. B- Internal chambers In the sediment chamber, heavy solids settle out, and concentrated slugs of oil rise to the surface. As the oily water passes through the parallel corrugated... 

A highly concentrated suspension of flocculated kaolin in water behaves as a pseudo-homogeneous fluid with shear-thinning characteristics which can be represented approximately by the Ostwald-de Waele power law, with an index of 0.15. It is found that, if air is injected into the suspension when in laminar flow, the pressure gradient may be reduced even though the flowrate of suspension is kept constant, Explain how this is possible in slug flow and estimate the possible reduction in pressure gradient for equal volumetric flowrates of suspension and air. 

As more air was added to the channel, the slug flow became unstable, the slug bubble broke down, and eventually the churn flow occurred in the channel. As shown in Fig. 5.3d, the most significant feature of flow characteristics in the churn flow is that the pressure oscillated at a relatively high amplitude, since the gas plug and liquid bridge flowed through the test section alternatively. 

This class of hybrid components comprises chip micro-reactor devices, as described in Section 4.1.3, connected to conventional tubing. This may be H PLC tubing which sometimes has as small internals as micro channels themselves. The main function of the tubing is to provide longer residence times. Sometimes, flow through the tube produces characteristic flow patterns such as in slug-flow tube reactors. Chip-tube micro reactors are typical examples of multi-scale architecture (assembly of components of hybrid origin). 

The following comments are based on the findings of Wypych (1989b) who compared the actual conveying characteristics of several materials with the slugging classifications of Dixon (1979) and Dixon (1981). 

A direct implication of this hypothesis is that phase transition of the mucus gel should be reversible, and it should exhibit the characteristic features of a critical phenomenon. Studies conducted in isolated giant mucin secretory granules of the terrestrial slug revealed that hydrated mucin gels, released from individual secretory granules, can indeed be recondensed. Recondensation/ decondensation is reversible and exhibits the typical features of a polymer gel phase transition. Namely, it is discontinuous, and is affected by pH, temperature and Ca2 + concentration in a fashion that mimics phase transition in synthetic polymer hydrogels [32, 33] (see Fig. 3). 

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