HOMOTOPIC METHODS TO SOLVE OPTIMAL SYNTHESIS OF MULTIPLE STAGE FLASH DISTILLATION

M. LORENA BERGAMINI; SERGIO MUSSATI; PIO A. AGUIRRE

Santa Fe, Argentina

Congreso; 3rd Mercosur Congress on Process Systems Engineering (ENPROMER´01); 2001

Seawater desalination may be achieved through successive flash evaporation processes. The produced vapour has to be condensed. A thermal exchange system and an external energy supply are needed in the desaltor complex. We are interested in finding a structure associated to the desaltor that involves minimum energy demand. There are two conflictive points: how to start the searching, for several values of heat exchange area (A0) or energy consumption (Q0), and how to obtain the global optimum for certain values of Q0 of interest. One way to confront the problem is using continuation methods. In the desaltor model a homotopy method for obtain a sequence of optimum is proposed. In this case, the curve starts in a region where the optimum can be easily reachable, and using A or Q as homotopy parameters, the trajectory of optimum for different values of A0 and Q0 is obtained.Points on the path far from the initial region show difficult convergence, due to nonlinearity in the functions. Bounds in variables and starting point take a very important role in the efficiency to track the complete solution path.0) or energy consumption (Q0), and how to obtain the global optimum for certain values of Q0 of interest. One way to confront the problem is using continuation methods. In the desaltor model a homotopy method for obtain a sequence of optimum is proposed. In this case, the curve starts in a region where the optimum can be easily reachable, and using A or Q as homotopy parameters, the trajectory of optimum for different values of A0 and Q0 is obtained.Points on the path far from the initial region show difficult convergence, due to nonlinearity in the functions. Bounds in variables and starting point take a very important role in the efficiency to track the complete solution path.