Hydaulic Power Recovery Turbine

[CCNY]

Apreciate help with the following question.

What would be the most likely consequence if liquid flow to a hydraulic power recovery turbine used to drive a pump were to suddenly be lost and high pressure gas instead of liquid starts to flow through the HPRT?

Thanks

 

[MikeHalloran]

Absent a check valve in the pump discharge, the reservoir into which the pump is discharging will drive the pump backwards, the pump will drive the turbine backwards, and if liquid is introduced to the turbine again, the shock load of sudden reversal will break something. ... if the first reversal didn't.

... That is but one possible scenario that could be constructed around the insufficiently specified problem you have provided. A different set of assumptions than those I inserted could result in an entirely different outcome.

I.e., there may be an infinity of possible event sequences that intersect the sort of fuzzy data point you have provided. If you are only concerned with event sequences that are possible with specific turbines and specific pumps and specific fluids, none of which you have identified either, there may be only half an infinity of possible intersecting event sequences, depending on an infinity of design details of the specific devices that you have not specified, and the design details of specific devices interfaced thereto, that you have also not specified.


IOW, if we had some ham, we could have ham and eggs, if we had some eggs.






Mike Halloran
Pembroke Pines, FL, USA

 

[CCNY]

Mike,

Thanks for your response in view of limited information I had supplied. Here is more eggs for the omlet.

The HPRT in question is a multistage "reverse" running pump that is fed from a high pressure Liquid/Vapor Separator Vessel. In normal operation liquid from the Separator flows to the HPRT and is let down in pressure. The recovered power is used to drive the feed pump to the unit. The feed pump in addition to check valves at its discharge is also fitted with safety instrumented system chopper valves that will close to prevent back flow through the pump in the event the feed pump trips ( this addresses your point on back flow through the feed pump).

The issue I am trying to address is in case the liquid from the high pressure liquid/vapor Separator that normally feeds the HPRT is lost, then high pressure gas from the Separator will start to flow through the HPRT. The question is if there a concern with gas blowing through the HPRT?

Thanks

 

[ccfowler]

It seems like a potential mess to me. I would include equipment to prevent that problem from happening. See my quote below about designing for graceful failure.

I've seen more than a sufficient number of unpleasant episodes that could readily have been avoided including incidents involving multiple fatalities and life altering injuries. Another worthwhile quote from another professor is, "the lowest price and the lowest cost are seldom, if ever, associated with the same set of alternatives."

Valuable advice from a professor many years ago: First, design for graceful failure. Everything we build will eventually fail, so we must strive to avoid injuries or secondary damage when that failure occurs. Only then can practicality and economics be properly considered.