Back Pressure Regulator on Recirculation Line

[AABT]

Hello,

I'm a recent graduate and I'm having trouble deciding whether or not to remove a back pressure regulator on a boiler feedwater pump recirculation line. The pump is oversized and the recirculation line constantly has flow running through it running back to the pump's reservoir.

Could anyone describe the overall process when determining the use of an RO or back pressure regulator?

I appreciate any feedback.

Thanks.

 

[mk3223]

Not clear about where is the back pressure regulator on what recirculation line.
For better understanding, it's nice to share a sketch of the system about the RO or regulator.

 

[LittleInch]

The process?
First gather all data, both mechanical (pump type size flow,boiler flow etc ) and operating - how does it work in practice, flow or level control, cost of power etc.

Then what are your goals in this?
Lower opex? Better operation?
How much money have you got to spend to fix your issue?

Recirculation systems ate sometimes a necessary evil but which design suits your particular requirements needs data and thought. ( i.e. Des ign...)

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

 

[RVAmeche]

To try to address the more general nature of your question, the recirculation line may be needed to keep the feedwater pump near its BEP (best efficiency point). If the boiler(s) in question have varying loads (and thus varying feedwater requirements), a regulator may be preferred because it can modulate based on the system condition. If the boiler(s) operate at a very steady state (for power generation or other reasons), a restriction orifice may be cost effective since you can size it for that one primary operating scenario. If the boiler has a range of operating loads, a restriction orifice will probably not result in the best pump efficiency and may result in too much/too little pressure drop.

 

[Latexman]

The two main functions of the BPR is to keep the boiler feedwater at a more constant pressure, so it does not ride the pump's curve, and to prevent dead heading of the pump. An RO does the latter but not the former, and is inferior to a BPR.

Good luck,
Latexman

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

 

[LittleInch]

But we don't even know if it's a centrifugal or PD pump yet?

I agree RO is a fairly basic system that can't adjust flow or pressure, but if flow and pressure are constant enough then they can work

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

 

[Latexman]

Chances are it's a multi-stage centrifugal. We'll see. Yes, RO can work, but it's inferior to a BPR, IMHO. Besides, the OP already has an BPR. Also, IMHO, why take a step backwards?

Good luck,
Latexman

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

 

[LittleInch]

So many questions, so few answers. ...

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

 

[georgeverghese]

Depending on the process conditions at the backpressure control valve, check if you need anticavitation trim; this will be required when there is internal flashing of warm BFW in the control valve trim.