The Closed-Cycle Turbine: Present and Future Prospectives for Fossil and Nuclear Heat Sources

Abstract

The closed-cycle gas turbine (CCGT) may well emerge in the foreseeable future as a major contributor to the U. S. electric utility industry because of: (a) its adaptability to coal-fired and to nuclear heat sources, (b) very high fuel utilization efficiency when the high grade waste heat is used, (c) potential for high degree of reliability and availability and low maintenance, (d) efficient, cost-effective dry cooling where no cooling water is available, and (e) an established technology base for commercial introduction into the power generation industry. In addition, the gas turbine HTGR provides a vehicle for demonstrating and developing the technology for economical nuclear process heat. In Europe, the closed-cycle gas turbine has demonstrated a high degree of reliability and availability, with both air and helium as working fluids. Power plants up to 50 MWe have operated successfully on a variety of liquid, gaseous, and solid fossil fuels. The waste heat thermal energy from these plants, in the form of hot water, has been used for urban and industrial district heating with the result that the fuel utilization efficiency has approached 80 percent, an impressive value indeed for an approaching era of energy conservation, where high power plant efficiency, and particularly high energy utilization effectiveness will be of the essence. In this paper, the established technology bases for closed-cycle gas turbines and high temperature gas cooled reactors (HTGR) are summarized.