4 replies to this topic

[sukanta87]

Hi,

am sizing the flare KO drum for NG process plant. Facing problem with the operating temperature and slop & drain volume. What should be the operating temp. or the range? Should it be the atmospheric temp.?

Another thing is the slop & drain volume. How it can be estimated? The liquid rate in the KO drum is considered based on the blowdown of the total system.  

Edited by sukanta87, 18 November 2013 - 03:52 AM.

[fallah]

Hi,

 

A general question will lead to receiving general answer:

 

The operating temperature of a KO Drum in NG services, depending on service pressure and composition, can be from -100 C to +100 C or even wider range. Then, the MOC of the shell and internals are normally LTCS and SS. Drain flowrate would be calculated based on maximum receiving inventory and its composition...

[sukanta87]

The service pressure of KO drum is assumed as 50 Psig and the streams heading to the flare header as well as to the KO drum are at different temperatures. It varies from 32-80 deg C. Compositions underlies in the stream conditions. It will be helpful to know the considerations usually taken to fix the operating temperature of KO drum for sizing.

For calculation, the liquid rate in the KO drum is considered based on the blowdown of the total system. And the maximum achievable liquid rate is through the inlet blowdown header. If it's considered the drain volume due to inlet blowdown, then what will be the normal liquid flow rate to the KO?

[fallah]

 If it's considered the drain volume due to inlet blowdown, then what will be the normal liquid flow rate to the KO?

 

Hi,

 

There isn't a normal liquid flow rate to KO drum. As i mentioned maximum receiving inventory among all credible scnarios in pressure relieving devices/systems either as one incoming stream or as combination of several simultaneous incomimg streams will be used in sizing a KO druim... 

[sukanta87]

Hi,

 

I understand your considerations. In API 521 p-65, a normal liquid rate and a drain liquid is supposed individually. The normal liquid rate is considered there at equilibrium of the NG flowing to the KO.