Design of Combined Heat and Power Plant using MINLP model

SERGIO F. MUSSATI

Lisboa

Conferencia; EngOpt 2010 - 2nd International Conference on Engineering Optimization; 2010

CPM - Centre for Mechanical Design, Instituto Superior Técnico

This paper presents a Mixed Integer Nonlinear Programming (MINLP) mathematical model to simultaneously optimize the configuration of a Combined Cycle Power Plant (CCPP), the geometric design and operating conditions as well. The whole process is modelled by considering detailed energy, mass and momentum balances. Physical and chemical properties of air, oil, flue gases, overall radiant exchange factor, convection coefficient, overall heat transfer coefficients are computed using nonlinear correlations. On the other hand, discrete decisions (integer variables) are employed to model the tube number, diameters and widths of tubes in each equipment section as well as the number of fins per unit length of tube among others. Continuous variables are related to the pressures, temperatures and flow-rates of gases and working fluid streams. GAMS (General Algebraic Modelling System GAMS) is used to implement and to solve the mathematical model. Once the proposed MINLP model was successfully validated with literature, it was solved considering different objective functions. The obtained results are presented and discussed in detail.