Fluidization regimes in non-slugging fluidized beds: the influence of pressure drop across the air distributor

• The purpose of the present work is to study the influence of the pressure drop across the air distributor on the bubbling conditions of thebottom bed of circulating fluidized beds (CFB). The bottom bed is the dense bubbling zone just above the distributor. The experimental workwas carried out in a 12 MWm CFB boiler and in a cold CFR Three different distributions of the bubble flow in time and space, termedfluidization regimes, were identified in the cold CFB: the multiple bubble regime with many small bubbles evenly distributed in the bed; thesingle bubble regime, characterized by the presence of only one bubble at a time in the bed; and the exploding bubble regime with large,single, irregular voids stretching from the air distributor to the bed surface. These bubbling conditions were observed during variations in thegas velocity and the distributor pressure drop. A comparison with the 2 mz cross-section CFB boiler showed that the boiler always operatesin the single or in the exploding bubble regime, which indicates a bubble flow that is not continuous and not well distributed over the crosssectionof the bed. The conditions in the boiler are influenced by the relatively large area of gas passage and the low pressure drop of theboiler air distributor.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Maskinteknik -- Energiteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Mechanical Engineering -- Energy Engineering (hsv//eng)

Nyckelord

Circulating fluidized bed

Fluctuation

Fluid dynamics

Bubbling bed

Fluidization regime

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art (ämneskategori)

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