Can relief valve at positive displacement pump discharge routed to blowdown vessel instead of suctio

[Amanda123]

Can relief valve at positive displacement pump discharge routed to blowdown vessel instead of suction? If yes, what operating and design pressure, also design capacity of blowdown vessel should be?

 

[racookpe1978]

What fluid, pressure, temperature, and safety code (country) are you working with?

 

[LittleInch]

Rather short and vague question so a rather short and vague response is:

Possibly
Operating and design pressures calculated from the flow rates, line sizes and connecting pressures
Design capacity of blowdown vessel must equal maximum capacity of the pump plus what ever else goes into the vessel

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[georgeverghese]

Conceptually you could, but there's a long list of checks to go through before your management would accept this concept for further development. Some of these checks would be:
a)Where does the vapor line from this blowdown drum lead to and is the worst case built up backpressure on this RV within limits for this RV?
b)What else does this blowdown drum do - does it receive low temp liquids that could freeze the incoming pump PSV liquid and block up the drum?
c)Assuming this pd pump operates at a much warmer temperature than the blowdown drum, does the design temperature of the drum suit the max liquid temp?
d)Any corrosive components in this pd pump PSV that this downstream BD (and its pump) is not designed for, from a materials of construction viewpoint ( H2S, ammonia, caustic, high chlorides, mercury etc)?
e)Is there sufficient high level trip protection at this drum ?
f)Does this drum receive any continous clean liquid streams, and what type of pump do you have at this drum ? Are the fluids from this pd pump PSV fouling / solids laden, and can this then mess up the continous operation of this blowdown drum pump ? Remember many PSVs' leak a little all the time.
g) Provided you have high pressure trip protection at this PD pump (and the normal operating pressure controls at this pump are working well), and high level trip protection at the blowdown drum, and you have a central control room where you have all alarms indicated, and the CR is continously manned, if you can find 5minutes of holdup between LCH(level control high) and LAHH at the blowdown drum for the max relief rate from this PSV (plus any other continous stream rates), that would be acceptable.
h) What type of pd pump is this; if this is a recip pump, are the discharge side pulsations well under control, and peak pulse pressure is well below 90% of PSV set pressure?

Pls note this list is not complete; there may be other concerns we dont know of, given the limited info provided.

 

[Amanda123]

Hi, Thank you all for the feedback. Sorry for the delay.The fluid is Slurry Contains 40 % (by Wt) Solids (Adipic Acid, Penta Erythritol & Phthalic Anhydride) in Fatty acids/Fatty alchol, pumping temperature and pressure is 90 deg c and 5 bar respectively. PSV set at 7 bar currently located at discharge of this PD pump and the relieving currently routed to suction of pump. We are considering to route the PSV relieving to a different pressure vessel (new system) or direct to the of vessel(existing) current pump suction.

 

[Latexman]

We are considering to route the PSV relieving to a different pressure vessel (new system) or direct to the of vessel(existing) current pump suction.

Why?

And, is the PSV a balanced bellows type valve? In addition to offsetting the effects of built-up, constant superimposed, and variable superimposed back pressure, the bellows acts to seal process fluid from escaping to the atmosphere and isolates the spring, bonnet and guiding surfaces from contacting the process fluid. This is especially important for corrosive services and fluids with solids.

Good luck,
Latexman

To a ChE, the glass is always full - 1/2 air and 1/2 water.

 

[sshep]

Relief back to the suction vessel sounds perfect- simple and easy to evaluate. Relief to a new system will have additional complexity.

Best wishes,
sshep