The Externally-Fired Combined Cycle (EFCC) is an attractive emerging technology for powering high efficiency combined gas and steam turbine cycles with coal or other ash bearing fuels. The key near-term market for the EFCC is likely to be repowering of existing coal fueled power generation units. Repowering with an EFCC system offers utilities the ability to improve efficiency of existing plants by 25 to 60 percent, while doubling generating capacity. Repowering can be accomplished at a capital cost half that of a new facility of similar capacity. Furthermore, the EFCC concept does not require complex chemical processes, and is therefore very compatible with existing utility operating experience. In the EFCC, the heat input to the gas turbine is supplied indirectly through a ceramic heat exchanger. The heat exchanger, coupled with an atmospheric coal combustor and auxiliary components, replaces the conventional gas turbine combustor. Addition of a steam bottoming plant and exhaust cleanup system completes the combined cycle. A conceptual design has been developed for EFCC repowering of an existing reference plant which operates with a 48 MW steam turbine at a net plant efficiency of 25 percent. The repowered plant design uses a General Electric LM6000 gas turbine package in the EFCC power island. Topping the existing steam plant with the coal fueled EFCC improves efficiency to nearly 40 percent. The capital cost of this upgrade is 1,090/kW. When combined with the high efficiency, the low cost of coal, and low operation and maintenance costs, the resulting cost of electricity is competitive for base load generation.
A long term program was initiated in 1987 to develop an electric utility indirect coal-fired gas turbine combined cycle. This initial program was supported primarily by U.S. electric utility organizations and had as a purpose the experimental assessment of a ceramic heat exchanger concept applied as a high pressure gas turbine air heater developed by Hague International. The purpose of the initial phase of the development program was to determine if the ceramic materials, then available for use in the air heater, would withstand the high temperature 2200 F (1204 °C) corrosive environment produced by the combustion of coal. Also, in this initial phase, the program was intended to evaluate means of preventing the fouling of the air heater by fly ash. This experimental work was successful. A second phase of the program to build a 7-MW thermal input prototype was initiated in 1990 under the auspices of a cooperative agreement with the U.S. Department of Energy Morgantown Energy Technology Center (DOE-METC). This work was funded by a consortium of electric utilities, utility organizations, industrial organizations, state agencies, international entities, and the U.S. Department of Energy-METC. New members joined the existing Phase I Consortium to participate in funding the second phase. This second prototype phase is nearing completion and test results are to be available beginning mid-1994. A third, or demonstration phase, of the indirect-fired gas turbine program was selected under the U.S. Clean Coal Technology Program Round V. in May, 1993. This demonstration phase is currently in the planning and preliminary engineering stage. The objective of this proposed demonstration phase is to repower an existing coal-fired power plant in the Pennsylvania Electric Company system at Warren, Pennsylvania (Figure 1). This paper describes the demonstration plant, and the anticipated role of the EFCC cycle in the power generation industry, as well as the performance and economic merits of the Warren repowering concept.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.