pressure control valves

[vmac100]

hi people,good work being done here.
my problemur gas supply is from a local utility.these pilot control valves help to reduce the pressure to the level required for our turbines.however,when the pressure from the local utility drops to a level,then our turbines shutdown on low gas pressure.
does anybody have an idea or experience with any type of valves that can perform the function of reducing the pressures to our acceptable level when the pressure is high and is still capable of maintaining the pressure at our acceptable level when the pressure is low?any other technologies that can help will be very well appreciated.thanks
NB:the presure upstream of our pressure control valve is 15-16 bars and downdtream 11-14 bars.once our downstream pressure falls below 11 bars,the turbines shutdown.

 

[EdDanzer]

Although I’m not familiar with flammable gasses, a device like a hydraulic accumulator will work. A check valve before a storage tank, but after the gas supplier’s deliver valve may be all you need.

 

[zdas04]

There are a bunch of variations on pressure-control valves. It sounds like you're using the cheepest--a differential-pressure regulator. That dumb valve just looks at the dP across the valve and tries to keep it constant. What you need is a "Pressure Regulating" valve that senses pressure downstream of itself and will go to full-open if the pressure gets below its set point. Lots of folks make them in an "ANSI 300" design, I'd look to Kimray in Oklahoma City, OK, or Fisher Valve Company in Houston.

Your fuel demand is certainly too high for an accumulator to be of much use.

David Simpson, PE
MuleShoe Engineering

http://www.muleshoe-eng.com

 

[hydrae]

vmac100

Gas Turbine (compressor-combustor-turbine)? if the gas supply pressure is below the operating requirements of your engine, the gas will not flow. The pressure inside the combustion chamber is 11 bar I assume, then the fuel needs to be at a pressure higher than the pressure inside the combustion chamber. The solution is a compressor to pump the gas pressure back up to your requirements, that is if the utility is willing to sell you gas when they are low on supply.
Hydrae

 

[jay165]

mac:

Don't know what part of the world you're in, but 11 bar seems very low for a minimum delivery pressure from a utility. Your high end 16 bar would a minimum down here in the US Gulf.

ZDAS has good suggestions. An accuumulator would get sucked dry in seconds (unless it was huge). And aside from being expensive and impractical, I doubt if the utlity would allow you to install a compressor to suck gas on their system. We cetainly wouldn't.

If the valve isn't the problem, ie it is going wide open when the pressure falls to say 12 bar, then you need to talk to the utility or better yet re-read the delivery contract and raise hell to get them to deliver at the contract minimum pressure, assuming it's greater than 11 bar.