SIMULTANEOUS MODULAR ALGORITHM FOR STEADY-STATE FLOWSHEET SIMULATION AND DESIGN.

The simultaneous modular algorithm offers many of the advantages of an equation-solving procedure while using the existing sequential modular software. This work presents theoretical analysis and experimental results of various implementations of the simultaneous modular algorithm. The split fraction model of a unit behavior (y equals ax) is shown to have worse convergence properties than Wegstein's algorithm in a sequential modular model exhibits stable convergence behavior. The difference split fraction model (dy equals adx) is shown to be equivalent to Wegstein's algorithm for a flowsheet with a single recycle loop. On systems with multiple recycle loops, the model exhibits better convergence than Wegstein's algorithm.