(421ag) Effect of Loop Seal Geometry on Solid Circulation Characteristics in a Circulating Fluidized Bed

Circulating fluidized bed system consists of two bubbling beds, riser, cyclone, upper and lower loop seal has been used for solid circulation between two bubbling fluidized beds. A vertical type lower loop seal has been used so far, but this lower loop seal requires high gas flow rate through the lower loop seal for fluidization and smooth solid circulation, and consequently, causes slugging behavior sometimes. To overcome these disadvantages, inclined type lower loop seal was proposed by this study. Solid circulation characteristics with change of lower loop seal geometry were measured and compared in a bubbling – bubbling - riser type circulating fluidized bed at ambient temperature and pressure. We could conclude that the inclined lower loop seal is better than the vertical type lower loop seal from the viewpoints of minimum flow rate requirement for stable solid circulation and solid height change during solid circulation.