Water shield in Top Nozzle of coke drum. 1

[Ronak_Patel]

Hello all..

What is the purpose of water shield provided around the top nozzle of coke drum ? why is it provided only on top nozzle of the coke drum ?
similar water shields are also provided at just above skirt/shell joints in some vessels.

 

[shvet]

Height of water shields are site specific as depends on firefighting strategy and operating pressure in firewater main during design fire.
A vessel skirt may have not firefighting means other that a watershield while a coke drum bottom nozzle may be sprayed by a firebrigade.

Your question is not clear. What is design of this watershield? Can you provide a sketch? Anyway process unit design documentation contains all answers you need. You should ask persons involved in design of this coker unit.

More details = better comments.

 

[Ronak_Patel]

@shvet thank you for your response. Im talking about highlighted plate in attached sketch. this is top nozzle on coke drum.

My question is why this plate ( water shield ) has been provided ? it is not provided on any other nozzles on top head of coke drum.

 

[shvet]

A watershield on other vessels have the same design?

 

[Ronak_Patel]

water shields are not provided on any nozzles for other vessels.

only few vessels have water shield with similar design just above skirt to shell joint.

 

[shvet]

Are those skirts protected from overheating by a fireproofing material, e.g. bricks cladding?

More details = better comments

 

[Ronak_Patel]

Yes, those skirts are protected from fire by fireproofing material.

 

[Christine74]

Sloped Rain Shields like the one shown are used to protect the the unjacketed annular portion of the insulation or fireproofing from absorbing water during a rainstorm. Coke drums operate cyclically so they are susceptible to Corrosion Under Insulation when they're not in service, so the insulation needs to stay dry.


-Christine

 

[Ronak_Patel]

@Christine74 thank you for your response.