OPTIMIZATION - Teach Yourself the Basics of Aspen Plus - page 191

Workshop 13.2b To facilitate the passing of pressure from the compressor to the
flash, it is necessary to set the flash pressure to zero on its input form. This problem
was run several times at starting compressor pressures, varying from 250 to 150. In
all cases the SQP algorithm converged, sometimes with output pass errors, but in all
cases a value of the final objective function was displayed under the Convergence tab.
Results showed that a pressure approaching 150 psi yielded the lowest value of the
objective function. Results of the SQP algorithm need careful checking.
Workshop 13.2c Although the optimization with three variables gave a con-
verged solution, runs at different starting points exhibited the same behavior as in
Workshop 13.2b.
REFERENCES
Aspen Plus Help, version 7.0, Optimization — Convergence.
Beveridge, G. S. G., and Schechter, R. S., Optimization: Theory and Practice , McGraw-Hill, New York,
1970.
Edgar, T. F., and Himmelblau, D., Optimization of Chemical Processes , 2nd ed., McGraw-Hill, New York,
2001.