A heat integration technique for designing a Rankine cycle power plant that is based on modelling the cycle as a multi-objective optimization problem is presented in this paper. The heat integration procedure uses the same scheme that is used in designing complex heat exchanger networks. The hot and cold streams are identified and the pinch point is determined along with minimum heating and cooling targets. An initial configuration is designed and a multi-objective nonlinear optimization formulation of the initial configuration is solved to obtain the best feedwater heater bleed rates The procedure is based on a Rankine cycle thermodynamic simulation, program, along with exergy accounting and other applications of heat integration techniques.
The best solution values of the power plant variables have been determined for a typical Rankine cycle base plant by solving a compromise decision support problem (DSP) with a solver called DSIDES. Variation of thermal and exergetic efficiency of the power plant with feedwater heater flow rates was investigated. The heat integration of the power plant based on pinch technology for the heat recovery streams showed that fuel savings up to 1% are achievable. When translated to dollars saved, these are sigificant for large power stations.