Approche de conception et d’optimisation de centrale solaire intégrée à cycle combiné inspirée de la méthode du pincement (partie II: réseau d’échangeurs de chaleur)

Steam production units (HRSG and HSSG) of ISCCS include several heat exchangers (economizers, evaporator, superheater, reheaters, etc.). The knowledge of the extended composites as a function of the solar input, allows the determination of the most critical zones for heat transfer but does not allow, in itself, the full knowledge of the real streams needed to be able to design an optimum heat exchanger network. The procedure proposed in this paper permits, from so called interaction factors which characterize the interdependancy between streams, the determination of the massflows in each stream. The choice of the best heat exchanger network must respect, for each operational conditions, the optimum evaporation levels (including pressures et temperatures) determined in part I, as well as the particular practical operational factors (independance or not between the various heat recovery units, etc.). The network design is done using the standard guidelines of pinch technology (respect of the minimum pinch DTmin for each heat exchanger close to the pinch temperature, separate design of the zone above and below the pinch temperature, etc.). The respect of the DTmin in the critical zones of heat transfer requires the use of stream splitting and the network includes heat exchanger tubes which are interlaced at the same level of the stack. One example of the best performing power plant designed on the basis of this approach is given.