Physical Aspects of Deposition From Coal-Water Fuels Under Gas Turbine Conditions

Deposition, erosion, and corrosion (DEC) experiments were conducted using three coal-water fuels (CWF) in a staged subscale turbine combustor operated at conditions of a recuperated turbine. This rich-quench-lean (RQL) combustor appears promising for reducing NO_x levels to acceptable levels for future turbines operating with CWF. Specimens were exposed in two test sections to the combustion products from the RQL combustor. The gas and most surface temperatures in the first and second test sections represented temperatures in the first stators and rotors, respectively, of a recuperated turbine. The test results indicate deposition is affected substantially by gas temperature, surface temperature, and unburned carbon due to incomplete combustion. The high rates of deposition observed at first stator conditions showed the need for additional tests to identify CWF coals with lower deposition tendencies and to explore deposition control measures such as hot gas cleanup.