5 replies to this topic

[VELU_BAPCO]

HELLO!

HAVE ANYBODY HEARD ABOUT RAIN DECK TRAYS?

WHAT TYPE OF TRAYS ARE THESE?

REGARDS,

VELU.

[harish]

Velu,
Its not clear on what context you`re asking this question.I suppose you`re talking about deck drains in offshore platforms.It will be easy for forum memebers if you could give some background information.

Regards
Harish

[djack77494]

Velu,
What you refer to as "rain deck trays" may be splash trays; for example, what are called "disc and donut trays" are a type of splash tray. Downflowing liquid just "rains down" from the upper part of the column to the bottom. The trays serve to force the fluids (liquid and counterflowing vapors) from side to side and to break up the liquid into droplets by repeated impacts. There are other types of splash trays besides the disc & donut, but all are fairly simple and generally inefficient (from a mass transfer viewpoint) devices. They do have some advantages - for example, they resist plugging and can handle solids if correctly designed. Let's hear back from you if that answer falls short of your needs.
Doug

[VELU_BAPCO]

Doug,


Thanks for your reply. I came across data of a Visbreaker unit main fractionator, which says that the column contains disc and donut trays and rain deck trays. I've seen disc and donut trays and your answer explains its functions and advantages. Can you throw some more light on Rain decks (Are these trays similar to disc and donut trays in construction)?

[djack77494]

I think what you are calling rain deck trays are just semi-circular plates that occupy half (+/-) of the column's cross-sectional area. I've seen them where they're basically half toe column, alternating between (say) the left and right sides. You could add flat or notched baffles, as desired. You could also have the plates obstruct more than half of the cross-sectional area. This I've seen done with holes drilled in a center segmental area of the trays. There are other arrangements I've heard of but am not very familiar with. I'm sure they all come with their own sets of advantages and disadvantages. There is also "grid" which is just a very, very open type of structured packing. Maybe that would work?

HTH,
Doug

[indy]

If you are talking about a Visbraker column, in the figure bellow on the bottom of the column these are the so called trays used.

http://www.freepaten...390-0-large.jpg


regards

luismarques