Representation of stoichiometric and reactive distillation lines

A third concept is introduced when chemical reaction and phase equilibrium phenomena are superimposed in the unit reactive distillation lines. The following sequence of phase equilibrium— chemical reaction steps is adopted for the evolution of reactive distillation lines, 

The starting point of this sequence is the reactive mixture xi on the chemical equilibrium line. This liquid mixture is in phase equilibrium with the vapor yl, which is totally condensed to x. Since this mixture is apart from the chemical equilibrium line, it reacts along the stoichiometric line to the equilibrium composition X2- As can be seen in figure 2.2, the difference of the slope between the stoichiometric and liquid-vapor equilibrium lines defines the orientation of the reactive distillation lines. This difference in behavior allows one to identify a point, at which both the phase equilibrium and stoichiometric lines are collinear and where liquid concentration remains unchanged. This special point (labelled A in figure 2.2) is conventionally referred to as reactive azeotrope and is surveyed in section 2.4. 

Based on the graphical estimation of reactive azeotropes. Prey and Stichlmair (1999a) establishes the following rules of thumb, 

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Figure 2.2. Representation of stoichiometric and reactive distillation lines for the reactive system A-B-C undergoing the reaction A+B C. Remark tt denotes the pole at which stoichiometric lines coincide, XiT, = VijT,Vj. Legend dashed line stoichiometric line dotted line phase-equilibrium hne continuous line chemical equilibrium line. System feature ...

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