Development of an Exergy-Rational Method and Optimum Control Algorithm for the Best Utilization of the Flue Gas Heat in Coal-Fired Power Plant Stacks

摘要: Waste heat that is available in the flue gas of power plant stacks a potential source useful thermal power. In reclaiming and utilizing this waste without compromising efficiency, usually need to be equipped with forced-draught fans order compensate for decrease natural draught while stack cooled. addition, pumps are used circulate transfer fluid. All these parasitic operations require electrical Electrical has unit exergy almost 1 W/W. On contrary, claimed from low-enthalpy much lower exergy. Therefore, an exergetic point view, additional required drive must not exceed claimed. Based on First-Law Thermodynamics, net energy saved may positive apparently high coefficient performance; however, same generally does hold true Second-Law. This matter determining optimum amount most rational method maximum gain process, under variable outdoor conditions operations. The four main methods were compared. These (a) electricity generation by thermoelectric generators, Organic-Rankine Cycle (b) or (c) pump, (d) direct use gained district system. comparison shows exergy-rationality best (b). A new analytical optimization algorithm exergy-based control strategy developed, which determine pump flow rate recovery system then calculate how forced-draft fan at dynamic operating conditions. Robust design metrics established maximize gain, including performance. Parametric studies indicate approach provides better insight showing can optimally recovered different than values given classical economic efficiency considerations. case study was performed (d), that, any rationality-based method, feasible systems other utilization recovered. implications field, since units industrial applications, designed based result loss instead therefore responsible more carbon dioxide emissions. applications retrofitted controllers speed selected capacities.