Isothermal reactor with recirculation

Figure 6.3 Schematic diagram of the isothermal reactor with recirculation...

Figure 14. Examples of concentration-driven recirculations in an isothermal (550 K) vertical CVD reactor for the growth of a Hg-containing compound at 101 kPa showing streamlines (left side) and isoconcentration curves (right side). The inlet Hg partial pressures were (a) 10.1 kPa and (b) 10.1 Pa (Reproduced with permission from reference 205. Copyright 1988 Elsevier.)...

This simplification is not possible for some CVD systems in which large density changes are associated with the deposition process. The growth of CdHgTe is a typical example that shows how the depletion of Hg next to the substrate creates an unstable density gradient that drives recirculations (205), as discussed earlier and illustrated in Figure 14. LPCVD processes use little or no diluent and often involve several species, and multicomponent diffusion may be an important factor (21). Fortunately, these reactors are isothermal, and the relative insensitivity of reactor performance to details of the fluid flow greatly simplifies the analysis. 

Equations will be derived for three representative cases the tubular reactor of annular cross-section the isothermal, well-mixed batch reactor and the isothermal batch reactor inside a recirculating system. The chosen exemplifications will deal with these types of reactors that are, without doubt, the most widely used. 

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