Mass balance equations multiple equilibria

Three types of algebraic equations are used in solving multiple-equilibrium problems (1) equilibrium-constant expressions, (2) mass-balance equations, and (3) a single charge-balance equation. We showed in Section 4B how equilibrium-constant expressions are written we now turn our attention to the development of the other two types of equations. 

SC (simultaneous correction) method. The MESH equations are reduced to a set of N(2C +1) nonlinear equations in the mass flow rates of liquid components ltJ and vapor components and the temperatures 2J. The enthalpies and equilibrium constants Kg are determined by the primary variables lijt vtj, and Tf. The nonlinear equations are solved by the Newton-Raphson method. A convergence criterion is made up of deviations from material, equilibrium, and enthalpy balances simultaneously, and corrections for the next iterations are made automatically. The method is applicable to distillation, absorption and stripping in single and multiple columns. The calculation flowsketch is in Figure 13.19. A brief description of the method also will be given. The availability of computer programs in the open literature was cited earlier in this section. 

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