Characterization of products from a gas turbine combustor fired directly with coal-water mixture

• Published in: Fuel (Guildford) 1987-04, Vol.66 (4), p.563-567
• Main Authors: Spiro, C.L., Chen, C.C., Wong, J., Kimura, S.G., Greegor, R.B.
• Format: Article
• Language: English
• Subjects: Applied sciences; coal-water mixture; Combustion of heterogeneous mixtures. Incineration; combustion products; Combustion. Flame; Energy; Energy. Thermal use of fuels; Exact sciences and technology; fuel technology; gas turbine; gas turbines; products; Theoretical studies. Data and constants. Metering
• ISSN: 0016-2361; 1873-7153
• DOI: 10.1016/0016-2361(87)90164-5

Deposits from the combustion of coal-water mixture (CWM) fuel under realistic gas turbine conditions were analysed. The CWM was burned in a scaled gas-turbine can combustor in which pressure, temperature profile, aerodynamics, and residence time were maintained in ranges representative of real gas turbines. Products of combustion were obtained using an air-quenched probe located in the combustor exhaust and on cooled deposition pins. Combustion efficiencies, as indicated by carbon burnout, were 95 and 99% at exit temperatures of 913 and 1066 °C respectively. Probe samples consisted of carbonaceous cenospheres of 1–20 μm diameter and aerosols consisting largely of iron, presumably as oxide. Further combustion of the cenospheres resulted in the formation of very small, spherical ash particles. Because of the small size of the ash particles and aerosols and the buoyancy of the cenospheres, erosion is not expected to limit engine life. Deposits obtained from the cooled deposition pins contained hematite and a potassium-bearing aluminosilicate species accompanied by sulphate and chloride in a sodalite local environment. Comparison of the probe and deposit revealed that the potassium-oxygen bond distance was longer for the deposits than for ash obtained from the probe, indicating a higher average coordination number for ash exposed to high temperature for prolonged periods. No alkali sulphates were found in the deposits, indicating that a classical hot corrosion mechanism may not be applicable in CWM combustion.