Entrainment Reduction Check

Entrainment reduction takes place in the vapor space. Here the velocity of the vapor stream is reduced to a velocity at which gravity settling of droplets of size Dp and larger can take place. These liquid droplets settle from the vapor stream when the vapor residence time in the vessel is equal to or greater than the time of droplet fall. For this condition, 

L = Drum length (or more correctly, the horizontal distance between vapor-liquid inlet and vapor outlet), ft. a= Vapor space, ft. 

For convenience, the settling velocity will be converted to a satisfactory performance term. Rah This term is defined as the ratio of the settling velocity to a base velocity of 0.227 [(pi -Pv)/Pvf-. That is. 

Enter the chart at the left-hand side with the vapor space. 

Align the mark on Index Line A with the design R h. Mark the intersection with Index Line B. 

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The entrainment reduction check is made on Figure 5-6, the nomograph for equation 5-4. Here are the steps to follow ... 

For those applications where a more complete design is required, the starting point for the entrainment reduction check is the droplet settling velocity. 

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