A Direct Coal-Fired 80 MW Utility Combustion Turbine-Status Report

Volume 3: Coal, Biomass and Alternative Fuels; Combustion and Fuels; Oil and Gas Applications; Cycle Innovations

Pillsbury

Diehl

et al. 1990

Self Cite

Under sponsorship of the Morgantown Energy Technology Center of the Department of Energy, the Westinghouse Electric Corporation and Avco Research Laboratory/Textron (ARL) are developing a direct coal-fired 80-MW combustion turbine. This is to be an element in a 207-MW direct coal-fired combustion turbine combined cycle, comprising another combustion turbine, a heat-recovery steam generator, and a steam turbine. Following conceptual and economic studies, the first experimental task has been to develop a direct coal-fired slagging combustor in small scale. A year’s testing with this unit has now been accomplished. It is thus possible to discuss experimental results in the areas of slag management, general combustor operability, coal fuel feed, heat loss, pressure loss, combustion efficiency, and emissions. Westinghouse and ARL selected the slagging combustor for use in this program because of its unique ability to accept inexpensive standard utility-type coal without sending excessive pollutants and particulates to the expander-turbine. It accomplishes this by burning the coal at a temperature high enough to melt the ash, and then removing the molten slag with an impact separator. This combustor is also of the rich-lean type, which allows it to emit very low levels of NOx. Sulfur oxides are controlled through injection of a sorbent which combines with gaseous forms of sulfur in the rich zone, and then takes them out with the slag. The plan in this program is to develop the slagging combustor in small scale at 12 million Btu/h (12.66 million kJ/h) heat input, 6 atmospheres pressure, and then move to design and verification testing of a full-scale 70 million Btu/h (73.85 million kJ/h), 14-atmosphere unit. It is with the smaller burner that this paper is concerned. During this period, coals have been fed into the 6-atm combustor exclusively in the dry-pulverized form with air as the carrier gas. To date, high- and low-sulfur eastern bituminous, and low-sulfur western subbituminous coals have been evaluated, with, and without sorbents, which have included various calcium and iron containing minerals. Coal samples have been of the 200 mesh size, and have not been beneficiated. Combustor operation has been efficient and repeatable and slag flow has been symmetrical and manageable. Slag removal has been greater than 90 percent and carbon burnout has been greater than 99 percent. Nitrogen oxide emissions meet the goals of EPA’s NSPS for coal-fired plants. Current tests are focused on the goal of 90 percent sulfur removal. Although some results are available, various sorbents and injection techniques continue under test.

“…Three coals have been tested (Pillsbury et al, 1989). They are a low sulfur eastern bituminous coal, Dorchester, from Virginia; a high sulfur eastern bituminous coal, Pittsburgh No.…”

Section: Methods Of Testmentioning

confidence: 99%

Recent Test Results in the Direct Coal-Fired 80 MW Combustion Turbine Program

Volume 3: Coal, Biomass and Alternative Fuels; Combustion and Fuels; Oil and Gas Applications; Cycle Innovations

Pillsbury

Diehl

et al. 1990

Self Cite

“…Sorbents were also pneumatically fed to the gasifier. Instrumentation, control and analytical facilities also supported the test operation (Diehl et al, 1989). In the testing, the gasifier temperature was maintains at a sufficient level for rapid partial-combustion of the coal, though not necessarily for slagging.…”

Section: Slagging Gasifier Pilot Testingmentioning

confidence: 99%

A Direct Coal-Fired Combustion Turbine Power System Based on Slagging Gasification With In-Situ Gas Cleaning

Newby

Volume 2: Coal, Biomass and Alternative Fuels; Combustion and Fuels; Oil and Gas Applications; Cycle Innovations

1997

Westinghouse began the development of a compact, entrained, slagging gasifier technology utilizing in-situ fuel gas cleaning for combustion turbine power cycles in 1986. The slagging gasifier is air-blown, and produces a hot, low-heating value fuel gas that can be combusted and quenched to combustion turbine inlet temperatures while maintaining low levels of NOx emissions. The U.S. Department of Energy sponsored engineering studies and pilot testing during the period 1986 to 1992. This work has shown that the technology has promise, although performance improvements are required in some key areas. A major challenge has been the development of in-situ removal of sulfur, alkali vapor, and particulate to low enough levels to permit its use in combustion turbine power systems without additional, external gas cleaning. This paper reviews the Westinghouse slagging gasifier, direct coal-fired turbine power generation concept; the pilot test results; and the current development activities that Westinghouse is engaged in.

“…Initial slagging combustor development has been in small scale by a program subcontractor, Avco Research Laboratory/TEXTRON (ARL), using a 7 lb/sec (3.2 kg/sec), 6 atm unit, (Diehl et al, 1989). Figure 3 is a photo of this combustor in their Haverhill, Massachusetts facility.…”

Section: Air From Compressor Secondarymentioning

confidence: 99%

“…molten slag and sorbent simply piled up in the bottom of the separator vessel, in full communication with the flowing gases, (Pillsbury et al, 1989).…”

Section: -A Limestone In Cwmmentioning

confidence: 99%

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Development of a 220-MW Coal-Fired Combustion Turbine Combined Cycle: Current Status

Pillsbury

Volume 3: Coal, Biomass and Alternative Fuels; Combustion and Fuels; Oil and Gas Applications; Cycle Innovations

Diehl

et al. 1991

Self Cite

In the eight-year, multicontractor program to develop a 220-MW coal-fired combustion turbine combined cycle plant, the team is now into its third year of subscale slagging combustor testing. Because of an ability to accept unbeneficiated, utility-grade coal, the slagging combustor is the key to the direct coal-fired combustion turbine. The projected plant will contain two 80-MW combustion turbines equipped with slagging combustors, two heat recovery steam generators, and a 65-MW steam turbine.In testing to date, the concept has demonstrated its ability to handle high-and low-sulfur bituminous coals, and low-sulfur subbituminous coal. Feeding the fuel in the form of pulverized coal has proven to be superior to coal-water mixture type feed. The program objectives relative to combustion efficiency, combustor exit temperature, NOx emissions, carbon burnout, and slag rejection have been met. Work continues to reduce alkali, particulate, and SOx levels leaving the combustor. Parametric studies have been made that focus on the latter two problems. They indicate that faster, more thorough slag removal between the rich and lean stages is the path toward achieving lower emission of SOx, alkali, and particulates. New components have been added to the subscale combustor for this purpose.