Shell-side flow

Palen, J. W. and Taborek, J., Solution of Shell-Side Flow Pressure Drop and Heat Transfer by Stream Analysis Method (Heat Transfer Research, Inc., Alhambra, CA), AICHE Chemical Engineering Progress Symposium Series No. 92, Vol. 65 (1969), pp. 53-63. 

Eor one shell and multipass on the tube side, it is obvious that the fluids are not in true counter-current flow (nor co-current). Most exchangers have the shell side flowing through the unit as in Eigure 10-29C (although some designs have no more than two shell-side passes as in Eig-ures 10-IJ and 10-22, and the tube side fluid may make two or more passes as in Eigure 10-IJ) however, more than two passes complicates the mechanical construction. 

Determine LMTD if flows are counterflow and apply the correction factor of Bowman et al, established for this type of unmixed shell-side flow (Figure 10-129). ... 

Palen, J.W. and TABORAK, J. Chem. Eng. Prog. Sym. Ser. No. 92, 65 (1969) 53. Solution of shell side flow pressure drop and heat transfer by stream analysis method. 

Kcurentjes et al. (1996) have also reported the separation of racemic mixtures. Two liquids are made oppositely chiral by the addition of R- or S-enantiomers of a chiral selector, respectively. These liquids are miscible, but are kept separated by a non-miscible liquid contained in a porous membrane. These authors have used different types of hollow-fibre modules and optimization of shell-side flow distribution was carried out. The liquid membrane should be permeable to the enantiomers to be separated but non-permeable to the chiral selector molecules. Separation of racemic mixtures like norephedrine, ephedrine, phenyl glycine, salbutanol, etc. was attempted and both enantiomers of 99.3 to 99.8% purity were realized. 

Allow a drop of 0.1 bar for the shell inlet and outlet nozzles, leaving 0.7 bar for the shell-side flow. So, to keep within the specification, the shell-side velocity will have to be reduced by around J(1/2) = 0.707. To achieve this the baffle spacing will need to be increased to 100/0.707 = 141, say 140 mm. 

These methods can be used to make a crude estimate of the likely pressure drop. A reliable prediction can be obtained by treating the problem as one of two-phase flow. For tube-side condensation the general methods for two-phase flow in pipes can be used see Collier and Thome (1994) and Volume 1, Chapter 5. As the flow pattern will be changing throughout condensation, some form of step-wise procedure will need to be used. Two-phase flow on the shell-side is discussed by Grant (1973), who gives a method for predicting the pressure drop based on Tinker s shell-side flow model. 

Ideal Axial Flow (a) Ideal shell-side flow. 

The effect of the fouling on the shell-side flow is to increase the cross-flow and increase the overall heat transfer coefficient for a fixed pressure drop (assuming the same fouling coefficients in both cases). 

Given the uncertainties associated with the calculations, especially those on the shell-side, a sensible design basis for the heat transfer area specification would be the shell-side flow characterized by the clean condition. Of course, the fouling coefficients for the shell-side and tube-side should be included to account for the surface fouling resistance. 

Variation of overall heat transfer coefficient with shell-side flow rate... 

Shell Side Flow vs. Tube Side Flow Y AnfnertP... 

I have not shown the flow of liquid on the cold side of the pumparound heat exchanger in Fig. 12.1, but we can calculate its flow. Let s assume that the specific heat of the cold-side liquid is 0.5 Btu/L(lb)(°F)]. Then the cold-side (or shell-side) flow is... 

But this is not the case with a floating-head exchanger. The tube-side fluid reverses direction in the floating head. It has to. There is no way to attach the tube-side outlet nozzle to the floating head. It is a mechanical impossibility. So we bring the tube-side fluid back to the top half of the channel head. So, half of the tubes are in countercurrent flow with the shell-side flow. And that is good. But the other half of the tubes are in concurrent flow with the shell-side flow. And that is bad. 

Shell-side flow. The hot shell-side flow enters the exchanger, as shown in Fig. 19.1, through the top inlet nozzle. Not shown on this sketch is the impingement plate, which is simply a square piece of metal, somewhat larger than the inlet nozzle. Its function is to protect the tubes from the erosive velocity of the shell-side feed. The plate lies across the upper row of tubes. 

Divide the pounds per second of shell-side flow by the fluid density in pounds per cubic foot. This will give you the volumetric flow in ft3/s. 

J. Lemanski and G.G. Lipscomb, Effect of Shell-side Flows on the Performance of Hollow-fiber Gas Separation Modules, 7. Membr. Sci. 195, 215 (2002). 

Cc = tube clearance, in P, = tube pitch, in S = shell-side inside diameter, in W = mass shell-side flow, lb/h... 

Species-concentration profiles, obtained by integrating Equation (13.20), are plotted in Figure 13.7 for the case of two reactions in series (A —> B —> C) occurring in a catalytic hollow-fiber membrane. The reactant A contained in the bulk phase on shell-side flow through the membrane where reacting produces the intermediate product B then, B is converted in the final product C. Variations on concentration profiles are present only inside the fiber, outside the fiber there is no variation due to the reaction. No diffusion limitation in the films were considered in the present model in order to focus on transformation inside the membrane. 

MSG Cnstina, C M G S Batista, J G V F Sousa, J A A M Castro, Modelling Multitubular Catalytic Reactors the Influence of Shell Side Flow , Chem Eng Set... 

FIGURE 38.7 Scheme of a tube-in-shell configuration with shell side flow parallel to the lumen side one. (a) Module and (b) un-uniform packing/section view. 

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