Development of a Direct Coal-Fired Combined Cycle for Commercial Application

Abstract

A program has been underway since 1986 by Westinghouse Electric Corporation, Textron, Inc., and the sponsoring agency, the Morgantown Energy Technology Center (METC) of the U.S. Department of Energy (DOE), as participants, to establish the technology base for coal-fired combustion turbines targeted for power generation (50 to 150 MW size units). The developed system must be able to burn unbeneficiated, low-cost, utility-grade coal and meet the EPA New Source Performance Standards (NSPS) for coal-fired steam generators (Thoman et al., 1987). Development of a high pressure (12 to 16 atms) slagging combustor is the key to making a direct coal-fired combustion turbine a commercial reality. In testing to date, a 6 atm slagging combustor, rated at 12 MMBtu/hr (12.7 MHkJ/hr) has demonstrated its ability to handle high- and low-sulfur bituminous coals, and low-sulfur subbituminous coal. The program objectives relative to combustion efficiency, combustor exit temperature and pattern factor, NOx emissions, carbon burnout, and slag rejection have been met. Today, Northern States Power, working with Westinghouse with assistance from Textron is developing a plan to commercialize a direct coal-fired advanced combined cycle (DCFACC). Included in this plan is a pilot plant (which does not include a combustion turbine) and a demonstration plant that would utilize a 50 MW combustion turbine. The first commercial DCFACC, which would Include a 100 MW combustion turbine, is scheduled to be operational by the year 2001. The cooperative effort among Northern States Power, Westinghouse, and Textron is financially independent of the work now sponsored by DOE/METC. This paper presents the status of the pressurized slagging combustor development program including recent work to reduce alkali, particulates and SOx levels leaving the combustor and gives an overview of our commercialization process and plan.