Geothermal Preheating in Fossil-Fired Steam Power Plants

摘要

A thermodynamic analysis of a hybrid fossil geothermal power plant in which the low-grade geothermal energy is used for preheating the feedwater in a fossil-fired steam power plant is presented. By restricting the geofluid to sensible heat addition, the entropy production in this process can be reduced. This results in an overall improvement in the utilization of the two energy sources. The performance of the hybrid system is studied in terms of suitably defined figures of merit. These include criteria for the choice of the appropriate hybrid utilization strategy, given the finite nature of geothermal and fossil resources. The question of optimum bleed conditions in a cycle comprising both geothermal and regenerative feedwater heating is discussed. (ERA citation 04:013105)