5 replies to this topic

[Butterfly]

Dear all

 

I have a distillation column, operating at low pressure (less than 1 barg). I have light hydrocarbons on top, and the scheme is: total condenser, with hot bypass pressure control. Main PCV is upstream the condenser, and the hot bypass line includes a differential pressure control valve.

 

If column pressure drops, the main control valve should close. My question is: can a failure in the pressure control loop lead to a vacuum contition in the column? The same way that if the pressure increases and valves does not open when required, I could have an overpressure.

 

Thanks for your help

[Technical Bard]

Why would you put the main PCV upstream of the condenser?  That is an odd configuration.   Usually pressure control of the column is on the accumulator vessel.  For a total condenser, the pressure is controlled by the vapour pressure at the condensing temperature.

[breizh]

Hello,

2 documents about controls on distillation columns .

Hope this is going to help you.

Breizh

[Butterfly]

Thanks. My scheme is similar to Figure 9 in the first attachment (in the scheme the PCV is upstream the condenser), with additional DP control in the vapor equilibrium line..

[breizh]

Hi Butterfly ,

You should check the design pressure of the tower and the failure modes for PCVs .

You may want to review your existing HAZOP .

Good luck

 

Breizh

Edited by breizh, 13 August 2018 - 08:26 AM.

[Butterfly]

Thanks for the advice!