Knockout drum liquid droplets, entrainment

Design methods are discussed elsewhere (417) and are based on limiting the maximum diameter of droplets entrained in the vapor stream. Maximum droplet diameter can be reduced by supplying a knockout facility upstream of the compressor. This can be either an enlargement of the vapor space above the top tray, an in-line liquid separator, or a separate knockout drum. Mist eliminators are effective and can be installed above the top tray or in the drum. If the vapor temperature is higher than the worst ambient conditions, the lines from the knockout facility to the compressor should either be kept short and insulated or be provided with liquid-removal facilities. 

A simple K-value calculation might be helpful here. Let s use Eq. (26.6) and Fig. 26.1 to calculate the tendency to entrain droplets of liquid in the knockout (KO) drum shown ... 

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