EVOLUTION OF A CONCEPTUAL DESIGN FOR A COAL FIREDnFLUIDIZED BED COMBUSTION FURNACE FOR A MIUS CLOSED CYCLE GAS TURBINE

摘要

In evolving the design of the gas-turbine power plant based upon a coal-fired fluidized bed combustion furnace, particular attention was given to the most critical component in the sys¬tem, i.e., the fluidized bed furnace and heater assembly.1 Vari¬ous layout arrangements of the economizer and recuperator rela¬tive to the fluidized bed were studied. Several configurations for the tubes in the heat transfer matrix of the bed and econo¬mizer were considered and the effects of differential thermal expansion on thermal stresses were analyzed. The possibility of tube vibration caused by either Karman vortex shedding or bed pulsation was examined. A relation between basic fluidized bed design parameters and the frequency of bed pulsations to be expected was derived in the course of this work. Particu¬lar attention was given to the accommodation of thermal expan¬sion in the manifolds, piping, plenum chamber, and furnace support structure to minimize thermal stresses. Configurations were chosen that would limit the leakage of dusty air or com¬bustion gas leakage to a sufficiently low level that the pump¬ing power would not be increased significantly, and the fur¬nace configuration was designed to limit heat losses to the engine room less than 1% of the system output. The various air tuyere designs that have been tested by different organi¬zations were examined, their problems noted, and one that seemed best suited to the MIUS application was chosen. Simi¬larly, a variety of coal and limestone feed systems was con¬sidered and two were chosen for evaluation in bench tests of full scale components. The various tube and furnace configura-tions considered were examined from the standpoint of access for inspection and maintenance.nA configuration has been evolved that seems to meet the many requirements reasonably well.