5 replies to this topic

[KartikJ@15]

I'm operating my reflux drum in vaccum and considering a min deign press. as 1.4 kg/cm2. wherein the flare header max. back pressure is around 1.5 kg/cm2 itself.do i need to consider this while considering the design pressure.

[Pilesar]

You will be designing the reflux drum pressure vessel for vacuum - preferably for full vacuum. This will require substantial wall thickness. Some amount of positive design pressure will be automatic because of the wall thickness and will likely be greater than the 1.5 kg/cm2 anyway. You won't be adding much cost to the vessel to choose a design pressure comfortably higher than that. Then there would be cost savings in the relief system design which might more than offset specifying the higher design pressure. Usually there is a minimum positive pressure specified for the plant pressure vessels in similar service. Find that value and conform to it.

[latexman]

Specify full vacuum and design temperature to your vessel designer or fabricator, and tell them to furnish/calculate the resulting MAWP.  It depends on the dimensions of the drum, but my SWAG is, it will be about 3 to 4 kg/cm2.

[fallah]

KartikJ@15, on 06 Aug 2024 - 03:31 AM, said:

I'm operating my reflux drum in vaccum and considering a min deign press. as 1.4 kg/cm2. wherein the flare header max. back pressure is around 1.5 kg/cm2 itself.do i need to consider this while considering the design pressure.

 

Hi,

 

Please, at first, let's know if the pressures are in absolute or in gauge values...

[KartikJ@15]

fallah, on 06 Aug 2024 - 2:08 PM, said:

 

KartikJ@15, on 06 Aug 2024 - 03:31 AM, said:

I'm operating my reflux drum in vaccum and considering a min deign press. as 1.4 kg/cm2. wherein the flare header max. back pressure is around 1.5 kg/cm2 itself.do i need to consider this while considering the design pressure.

 

Hi,

 

Please, at first, let's know if the pressures are in absolute or in gauge values...

 

it's in absolute.

[fallah]

KartikJ@15, on 07 Aug 2024 - 03:52 AM, said:

 

fallah, on 06 Aug 2024 - 2:08 PM, said:

 

Hi,

 

Please, at first, let's know if the pressures are in absolute or in gauge values...

 

it's in absolute.

 

 

Then 1.4 kg/cm²a is equal to 0.4 kg/cm²g, hence are you operating a drum in vacuum condition while it hasn't already been designed for that condition?

Edited by fallah, 07 August 2024 - 12:16 AM.