This paper describes coal-fired, indirectly heated, air turbine combined cycle cogeneration plants that employ atmospheric pressure external combustion of coal, an open cycle gas (air) turbine, and a steam turbine. Air to operate the air turbine is heated indirectly, by hot fluidized solids contained inside tubes. The result is a high efficiency system that burns coal (or almost anything that will burn), does not require extensive operator training or support facilities, and emits low quantities of sulfur, NOx and particulates. The plant is capable of supplying electrical power, process heat, steam, and clean hot air in varying quantities, depending on the application. Uses exist in the chemical, petroleum, mining, metallurgical, paper, and textile industries and in enhanced oil recovery.
Thermoeconomical optimization of a regenerative air turbine cogeneration system
