SIMULTANEOUS MODULAR DYNAMIC SIMULATION - APPLICATION TO INTERCONNECTED DISTILLATION-COLUMNS

Key issues related to the use of the Simultaneous Modular Approach as a basis for an efficient dynamic simulator are presented. The proposed strategy is articulated roughly at two calculation levels. First, the module level, where the model and local control loop equations are solved all together via a global approach using an adapted Gear's integration code for DAE systems. Features and problems (consistent initialization, index problem, discontinuities, ...) encountered at this level are discussed in the proposed context. Second, at the flowsheet level, recycle and control equations are solved simultaneously wing a DAE integrator along with Dynamic Sensitivity Matrix techniques used to promote the convergence. Testing of this strategy - with comparison to other approaches - was previously performed on flowsheets with interconnected flash units. It is extended here to flowsheets with highly interconnected distillation columns. Future perspectives and evolutions are then discussed.