The objective of this effort is to establish the technology required for private sector use of an advanced coal-fueled gas turbine power system. The system is to burn low-cost, utility-grade coal, and yet comfortably meet the EPA New Source Performance Standard (NSPS) for coal-fired steam generators. Plant thermal efficiency is to surpass competing coal-utilization cycles. Development of a successful high pressure slagging combustor is the key to meeting these objectives. As subcontractor to Westinghouse, Avco Research Laboratory/Textron (ARL) has designed and fabricated a subscale slagging combustor based on earlier MHD and boiler-type units. The new device is currently in a 12½-month developmental series of tests. Based on these series of tests, Westinghouse is to design, manufacture, and test a full-scale slagging combustor in a test cell at nominal field operating conditions. The activities described in this paper are sponsored by the Morgantown Energy Technology Center of the Department of Energy.

Addition of a fluidized bed combustor to a high efficiency combined cycle plant enables direct firing of inexpensive run-of-the-mine coal in an environmentally acceptable manner. To attain high thermal efficiencies, coal pyrolysis is included. The low heating value fuel gas from the pyrolizer is burned in a topping combustion system that boosts gas turbine inlet temperature to state of the art while the pyrolizer-produced char is burned in the bed. The candidate topping combustor, the multi-annular swirl burner, based on a design by J. M. Beér is presented and discussed. Design requirements differ from conventional gas turbine combustors. The use of hot, vitiated air for cooling and combustion, and the use of low heating value fuel containing ammonia are two factors that make the design requirements unique. The multi-annular swirl burner contains rich-burn, quick-quench, and lean-burn zones formed aerodynamically rather than the physically separate volumes found in other rich-lean combustors. Although fuel is injected through a centrally located nozzle, the combustion air enters axially through a series of swirlers. Wall temperatures are controlled by relatively thick layers of air entering through the various swirler sections, which allows the combustor to be of all-metal construction rather than the ceramic often used in rich-lean concepts. This 12-inch diameter design utilizes some of the features of the previous 5-inch and 10-inch versions of the multi-annular swirl burner; and, test results from the previous projects were utilized in the formulation of the test for the present program. In the upcoming tests, vitiated air will be provided to simulate a pressurized fluidized bed effluent. Hot syngas seeded with ammonia will be used to simulate the low BTU gas produced in the pyrolizer.

As part of a continuing experimental development program supported by the U. S. Office of Coal Research, to prepare the gas turbine portion of an integrated gasification and power generation plant, emissions from scaled and full size coal gas combustors have been measured. Fuel used was a mixture of carbon monoxide, hydrogen, carbon dioxide, methane; and nitrogen, blended to match low heating value coal gas from an air-blown gasifier. The results of testing in a full scale, high pressure combustor rig are compared with the small scale work with respect to carbon monoxide and nitrogen oxides emissions, and the implications for design discussed.

Dow Chemical, U. S. A., is currently operating two Westinghouse W501D5 combustion turbines with synthetic gas from the commercial demonstration coal gasification unit at Plaquemine, Louisiana. The first of these units was fueled with synthetic gas in April 1987. This conversion followed several years of experimentation and prototype work by Dow and Westinghouse. The second unit began operating with synthetic gas during September 1987. Addition of synthetic gas capability to these combustion turbines, originally installed in December 1982 and May 1983, was relatively straightforward, and once installed, did not adversely affect their operation or efficiency on natural gas, or mixtures in various proportions with synthetic gas. For durability assessment, special instrumentation was maintained at the site in the months immediately following conversion. This facilitated making minor changes to improve combustor longevity. The heat recovery units were modified for synthetic gas operation to improve corrosion resistance and to handle higher temperatures. Minor adjustments were made in the controls to accommodate changing gas flow. Emission monitoring was enhanced.

A combustion turbine combined cycle that uses coal-derived dirty fuels can be economical if the fuel is processed at the plant site and cost of electricity (COE) is used as the criterion for configuring the power system and selecting its components. In a DOE/METC-sponsored study, 12 combinations of power components and conditioning components were evaluated for each of two fuels: a gas made from coal and a coal/water slurry. One baseline system was selected from each group of 12 systems, based on its potential to achieve a low COE. Each baseline system was then parametrically evaluated to show the effects of specific components on the COE of the power plant. In one of these studies, on-site coal conversion was shown as the key to reducing the COE and the operating cost of the plant, thus improving the chances of the plant being used for baseload operation. Power TrainsClean-Up Systems