Two-Stage Slagging Combustor Design for a Coal-Fueled Industrial Gas Turbine

A full-size combustor for a coal-fueled industrial gas turbine engine has been designed and fabricated. The design is based on extensive work completed through one-tenth scale combustion tests. Testing of the combustion hardware will be completed with a high pressure air supply in a combustion test facility before the components are integrated with the gas turbine engine. The combustor is a two-staged, rich-lean design. Fuel and air are introduced in the primary combustion zone where the combustion process is initiated. The primary zone operates in a slagging mode inertially removing coal ash from the gas stream. Four injectors designed for coal water mixture (CWM) atomization are used to introduce the fuel and primary air. In the secondary combustion zone, additional air is injected to complete the combustion process at fuel lean conditions. The secondary zone also serves to reduce the gas temperatures exiting the combustor. Between the primary and secondary zones is a Particulate Rejection Impact Separator (PRIS). In this device much of the coal ash that passes from the primary zone is inertially separated from the gas stream. The two-staged combustor along with the PRIS have been designated as the combustor island. All of the combustor island components are refractory-lined to minimize heat loss. Fabrication of the combustor has been completed. The PRIS is still under construction. The combustor hardware is being installed at the Caterpillar Technical Center for high pressure test evaluation. The design, test installation, and test plan of the full-size combustor island are discussed.