5 replies to this topic

[Manoj Hargude]

Dear All,

 

I need to size PSV situated on stripper column. Column is used for stripping off the sour gases from inter sour water by means of live LP steam. Column has a OH air cooler, reflux vessel and total reflux being send back to column and vapor leaves from of the reflux vessel to SRU unit.

 

Inlet feed (sour water) is preheated in preheater by means column bottom feed thereby facilitating better stripping in column.

 

I have attached sketch for more clarity.

 

I have identified credible scenrios as below,

 

1. Fire case

2. Loss of feed.

3. Inadvarant opening of steam control valve

4. Loss of reflux

5. Total blocked outlet.

6. Air cooler fan failure case.

 

Please correct if I am wrong and adwise on the different scnerios selection on PSV sizing.

 

Also adwise on the estimation of relief load for loss of feed case and air cooler fan failure case.

 

Regards,

Manoj

[fallah]

Manoj,

 

Nothing attached!

[Manoj Hargude]

Fallah,

 

Find attached missing sketch for your information.

 

Regards,

Manoj

Attached Files

•  Stripper Column PSV Sizing.pdf   178.22KB   208 downloads

[fallah]

Manoj,

 

Air cooler fan failure also covers loss of reflux case. Then for estimation of relief load for air cooler fan failure:

 

-Consider feed rate, stripping steam rate, deta P across the column,... at normal operating conditions and set the column top pressure at relieving pressure. Then consider HYSYS output vapor rate as preliminary relief load for this scenario.

 

 For estimation of relief load in loss of feed case:

 

- Set the column top pressure at relieving pressure with no feed while the live steam is fed to the stripper and estimate the delta P across the column. Then consider the HYSYS output vapor as relief load for this case.

Edited by fallah, 21 May 2013 - 04:07 AM.

[Dacs]

For estimation of relief load in loss of feed case:

 

- Set the column top pressure at relieving pressure with no feed while the live steam is fed to the stripper and estimate the delta P across the column. Then consider the HYSYS output vapor as relief load for this case.

I'm curious, as per sketch it's on ratio control, so if feed is lost, so does the steam feed to the column.

 

How can it overpressure then?

[fallah]

I'm curious, as per sketch it's on ratio control, so if feed is lost, so does the steam feed to the column.

 

How can it overpressure then?

 

Dacs,

 

Due to no credit on favorable instrument response when needed...

Edited by fallah, 22 May 2013 - 04:19 AM.