ASME VIII states that a 21% overpressure should be used for fire or other unexpected sources of heat. I usually see "fire" interpreted as meaning a pool-fire.
Does anyone have any examples of "unexpected external sources of heat?" Any example specific to refineries that you have designed for in...
A bit of a brain twister:
What happens to either a centrigfugal or PD pump that has its discharge valve closed, and then subsequently the inlet valve closed.
I know it will overheat, and explode/melt eventually. For the PD pump assume a PSV opens and disharges back to the suction line. For the...
Hello,
I recently had a discussion about how much pressure difference or flow rate is sufficient for purging H2S from a blower casing.
Due to a low casing design pressure, there were concerns that there was not enough driving force to get a sufficient purge.
Does anyone know a reference to a...
Hello,
We have a storage tank that will be filled via truck deliveries. The truck will be pressurized to 20 psig with N2 to offload the inventory into the tank. I would prefer to use a pump, but the client prefers N2 offloading.
A pressure regulator is designed to provide a maximum N2 flow of...
COnsider two pumps in series. Pump A is feeding Pump B.
A couple questions I have been stumbling over:
Somebody has told me that it is possible for Pump B to flow at a higer rate than pump A and therefore draw a vacum on the suction side of Pump P.
Is this actually possible? Or will as many...
Does anybody have any experience in designing instrumentation flush systems for instruments in slurry (FCC frac bottoms) service?
Is it common to use intermittent or continuous flushes? Hardpiped?
Any advice?
Thanks.
Jon
Hello,
We have a pilot psv on a superheated 600 psig steam line. We operate close to the set pressure of the psv, hence a pilot psv was selected.
We were told by the vendor that the maximum temperature the o-rings, etc... can handle is around 400 F. Therefore, there is a condenser on the...
I am interested to know/understand the standard control configuration for 2 pumps in series.
What i have seen is the first pump (fed from tank) has discharge valve controlled by tank level.
The second pump has its discharge valve controlled by suction pressure of the second pump.
Is it...
Hi,
My question is when calculating the 3% loss in the inlet pipe from the vessel to the psv inlet should the pressure of the vessel be assumed to be at the set pressure or the set-pressure+10% (to account for overpressure)?
For example if the set pressure is 100 psig. then i think i should...
Hi,
I am very new to ASME codes. Can somebody provide guidance on the following:
A steam coil is placed in the flue gas chimney of a process furnace. A type of waste heat recovery i guess. The steam goes to a shared steam drum. The steam drum accepts steam from other heat exchangers etc...
Hi,
could any one tell me if the relevant codes allow for the following situation:
A psv needs to be serviced while the unit is still operating. Therefore, isolation valves are installed and a manual bypass line is used. An operator stands by on radio and opens the manual valve in the case of...
Hello,
Please consider this example:
I have a P&ID with a 2" gate valve. I have no equipment data sheet on this valve. It is not stated to be full port.
What i want to know is what is the valve area.
My question is :
Is there a standard bore size for gate valves? For example a 2" gate...
Hello,
I am very new to safety valve sizing. I had 2 questions i hope someone could help me with:
1) How do you calculate the built-up back pressure required for the sizing of a psv when you dont know the size of the psv? I thought the built-up back-pressure would be a function of valve size...
