摘要 |
The system includes a boiler (20) having a fluidized bed (12) which provides heat from burning coal for generating steam used to drive a steam turbine generator (22, 24). After air from compressor 17 has been heated to 1400 DEG F in a fluid bed air heater (64), it is further heated in combustors (54) of a combustion turbine (14) by combustion of a gas as obtained from low temperature pyrolysis of the coal in another fluidized coal bed (16) which is pressurized. The hot gaseous products drive the combustion turbine (14) and a connected generator (15), whereafter the gaseous products are ducted at (66) to the boiler (20) where they fluidize the bed particles and supports full combustion of the bed (12). Char from the pyrolysis and supplementary coal are burned in the bed. Sulfur in both the coal or char and the gas turbine exhaust is captured by limestone in the bed. The high heating value of the pyrolysis gas and the high air preheat require a relatively small volume of gas. <IMAGE> |