Experimental and scaling studies on circulating fluidized beds

The measurement of the solids recycle rate in circulating fluidized beds with very high recycle to solids feed rate is not straightforward. Any attempt to divert the stream of solids from the cyclone for determination of recycle rate will upset the flow patterns or drain the solids inventory of the reactor. In addition, calculation of the recycle rate from simple measurements of the pressure drop across the height of the reactor is shown not to yield reliable results.; A one-fourth scale model of an existing, pilot scale prototype dry scrubbing process, that uses a circulating fluidized bed (CFB) for contacting sulfur laden flue gas with a hydrated lime slurry, was built and tested. The flow of the gas-solids suspension within the riser section of the scale model and the prototype was shown to be in the core annular flow regime, with a dilute rising core at the center and a dense falling annular region near the wall.