Axial-annular flow reactor

Hydrolysis of lactose to glucose and P-galactose (P-galactosidase) Axial-annular flow reactor Delactosization of milk or whey for human consumption... 

Another type of reactor has one or more annular beds of catalyst with radial flow of gas either inward or outward [5], as shown in Figure 3.12b. This type may be preferred when the diameter of an axial-flow reactor would be much greater than the required bed depth. By putting the same amount of catalyst in a narrower but longer reactor, the wall thickness can be reduced and the reactor cost decreased. This is particularly important for high-pressure reactions, such as the synthesis of ammonia. 

Modeling Concepts We shall model the axial flow in the annular region as being laminar. This assumption is reasonable because a typical Reynolds number for flow in a LPCVD reactor is less than 1. As the reactant gases flow through the annulus, the reactants diffuse from the annulus radially inward between the wafers to eoat them. 

An electrochemical reactor containing two concentric cylindrical electrodes (Fig. 2.7), with or without a diaphragm, represents a practical and attractive geometry since it offers a uniform primary current distribution (see Chapter 5). Axial flow through the annular space between the two electrodes, or an electrode and a diaphragm, has characteristics between those of a pipe and a rectangular channel. A theoretical analysis for the condition of laminar or turbulent flow is approached in the same way as that for pipes and channels hence, we merely identify appropriate experimental correlations. 

The flow model was taken from cin unpublished report described In the Appendix. The reactor Is considered to consist of a set of annuli each containing cin equal portion of the volumetric flow. The axial distance Is broken Into subdivisions whose size is dependent upon the stability analysis of the numerical technique. The physical properties at the entrance of each annular section are considered constant in the radial direction. At each axial point, these properties are calculated and the radial coordinate Is resubdlvlded into new annuli. The heat balance is then obtained from the differential equation in cylindrical coordinates transformed Into a difference equation of trldlagonal form which was solved by the method of L.H. Thomas (Reference 6). 

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