Lean phase flow transport

Lean phase fluidization As the gas flow rate increases beyond the point corresponding to the disappearance of bubbles, a drastic increase in the entrainment rate of the particles occurs such that a continuous feeding of particles into the fluidized bed is required to maintain a steady solid flow. Fluidization at this state, in contrast to dense-phase fluidization, is generally denoted lean phase fluidization. Lean phase fluidization encompasses two flow regimes, these are the fast fluidization and dilute transport regimes. 

In the entrained-flow reactor (Figure 18.11), the solid particles travel with the reacting fluid through the reactor. Such a reactor has also been described as a dilute or lean-phase fluidized bed with pneumatic transport of solids. 

In conventional pneumatic transport, a minimum in the dPjdz vs. Gs curve at a fixed gas velocity is commonly used to separate dense phase flow from lean phase transport (Leung, 1980). Experimentally, internal solids circulation increases dramatically right after... 

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