Back pressure regulator(PCV) set pressure query 1

[knapee]

Dear Sir:


The back pressure regulator located on the
nitrogen purge line (upstream pressure=10kg/cm2g)
open to relieve the pressure when the pressure upstream
increase above the set point.Upstream pressure regulators(
back pressure regulator) close upon loss of upstream pressure.


However, the downstream is vessel which OP=5kg/cm2g
Could you please help me how to determine the set pressure
for this PCV ?

Is PCV set pressure=3kg/cm2g or 6kg/cm2g will be most appropriate for this case?

Appreciate for your any comment and thank you very much.

 

[knapee]

Dear Sir

Cause no one would like help me out.

I would like to post this process diagram to explain my query

Case1 Upstream pressure regulator,

Is possible that we have to make the set pressure

the same as upstream pressure.


Case2. Downstream pressure regulator,

Is it possible that we must make the set pressure

equal to the downstream pressure? Or it is depend on the process case.

Could you please help me some example?

Thank you so much.

 

[SeanB]

I don't think it is a case of anyone not wanting to help you - but the problem statement is a little confusing. If I understand you correctly it is the Case 1 configuration that you have drawn is correct. You have a nitrogen system that is being maintained at 10 kg/cm² - if pressure exceeds this value the regulator opens to bleed off the pressure into the vessel - this is perfectly acceptable. However, you would have to evaluate the PCV failure case meaning if the PCV failed open exposing your vessel to the full upstream pressure is it then possible to overpressure the downstream vessel?

 

[vk1975]

Hi

Your query is still not clear. Kindly provide the total process/ information in the sketch for everybody to understand. Solution can be provided only when problem is understood correctly.

 

[Pumpsonly]

ARe you talking about 2 individual cases or they are connected?

Assuming you are talking 2 individual cases.

For case 1 ,If you want to maintain the pressure up stream of the PCV at 10kg/cm2 then set is at 10kg/cm2.

For case 2, if you want to maintain the pressure of the vessel at 5kg/cm2, then set it at 5.

 

[koba78]

1.The back pressure regulator valve
The initial position of the valve stem is at open position, as the downstream
pressure increase, the valve will close accordingly till the valve pressure reach its set pressure.

2. The upstream pressure regulator valve
The initial position of the valve stem is at close position, as the the upstream
pressure increasing, the valve will increase
accordingly till the valve pressure reach its set pressure.


But, could anyone share any PCV application ?