5 replies to this topic

[deltaChe]

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.

[fallah]

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.

steven7788,

Please submit a simple sketch of your system. It has great effect on clarifying your query lead us to present a proper and effective response.

Fallah

[deltaChe]

Dear Sir

Thank you for your reply

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.

Attached Files

•  2011-11-09_211137.jpg   64.56KB   22 downloads

[fallah]

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.

steven7788,

In case 1 you should set the pressure in order to keep its value constant at upstream. Hence, you should set it at 10 kg/cm2 if you want to keep upstream pressure costant at this value. Obviously, downstream pressure would be variable.

In case 2 you should set the pressure at the value which you want to keep it constant at downstream. Thus, process conditions may dictate the value of downstream pressure to be fixed. Obviously, upstream pressure could be variable.

Fallah

Edited by fallah, 10 November 2011 - 02:06 AM.

[latexman]

Case 1 is a back pressure regulator.

Case 2 is a pressure regulator.

[deltaChe]

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 ?