vacuum towers feed inlet devices

[qazx]

hello,
There are three methods for feed entering to the vacuum towers(as I know):
1)Tangential
2)Tangential (vane type)
3)Radial (vane type)
Are there any person who compare the performance of these different types in all view points(flow distribution,phase separation,pressure drop,entrianment,...)?or have experience(s) on each type?or have some operating data on each type?or any information....

 

[25362]

Designs I've seen on feed inlet to the flash zone of refinery vacuum towers consist of wide tangential downward internal inverted "L" attachments to induce separation of asphalt or pitch from cleaner upgoing vapours by cyclone- type action.