4 replies to this topic

[Steady]

Hello Everyone

 

I am interested to know the reason(s) of having multiple gas outlet nozzles on a  Flare KO horizontal Drum.

 

I have come across this flare KO drum design which has an inlet line & nozzle of 30" at the middle of the drum and there are two 24" gas outlet nozzles at the top ends of the drum. These two 24" inlet nozzles then join into one 30" flare header to the stack.

 

I am wondering why would you have two outlet nozzles?  I am looking for some generic answers to this. My guess is that it somehow results in low required length for the drum but i am not sure.

 

Its an existing design and drum has been there for nearly 25 years.

 

Please see attached a snapshot of the P&ID which shows the drum and its inlet and gas outlet nozzles.

Attached Files

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Edited by Steady, 01 April 2014 - 06:26 AM.

[PingPong]

The incoming vapor is plit in a flow to the left, and one to the right, paasing through the drum.

In this way only half the vapor area cross sectional above the maximum liquid level is required and the flare KO drum can be smaller than with only one outlet nozzle.

[fallah]

 

I am interested to know the reason(s) of having multiple gas outlet nozzles on a  Flare KO horizontal Drum.

 

I have come across this flare KO drum design which has an inlet line & nozzle of 30" at the middle of the drum and there are two 24" gas outlet nozzles at the top ends of the drum. These two 24" inlet nozzles then join into one 30" flare header to the stack.

 

I am wondering why would you have two outlet nozzles?  I am looking for some generic answers to this. My guess is that it somehow results in low required length for the drum but i am not sure.

 

 

Steady,

 

Such configuration and also the configuration with "vapor entering at each end of the horizontal axis and a cetre outle" are to be used in order to reduce the KO Drum diameter (but in the expense of increasing the drum length) for large flowrates in which the drum diameter exceeds 12 ft (3.66 m)...

Edited by fallah, 01 April 2014 - 08:46 AM.

[Bobby Strain]

You can see the effects with software at my site. Just Google my name. Access the sample from the home page.

 

Bobby

[Pilesar]

The horizontal vapor velocity is one of the parameters to consider when designing a horizontal separator drum. If the velocity is too fast, the liquid can become entrained again into the vapor. The effect is similar to the ocean spray that results from a high wind across the water. When the vapor paths through the separator drum are doubled, then the horizontal velocity is halved. There is additional cost for the extra nozzle and piping which should be contrasted with the cost of a larger drum.