4 replies to this topic

[John C]

10-28-2006
Hello,
I am new to this forum and to posting in general. Hopefully the following is appropriate for this group. If not I apologize.

I am researching ways to control--or throttle--the flow of natural gas--methane. The situation is as follows: A gas manifold at a variiable pressure, but typically 25-30 PSI, supplies a number of branches. These branches are approximately 1" in diameter and they feed the gas to the individual cylinders of a large (18" + bore) natural gas engine. At the engine cylinders a mechanically operated valve opens/closes to admit the gas from the branch into the combustion chamber at the proper time in the engine cycle.
In large engines like this it is important that each cylinder produces the same amount of horsepower. One way this is done is by controlling the amount of gas to each cylinder. This, in turn is accomplished by a control valve (usually manually operated) located in the branch lines mentioned above.
We are researching the best type of valve to use for this purpose. We are considering globe-type flow control valves, butterfly valves and rising plug type valves. I am very interested in your thoughts on these and other types of valves and what their relative merits are.

Finally, I am also looking for good references for selecting/sizing valves for compressible fluids.

The conditions are roughly as follows: Manifold pressure 25-30 PSI, flow rate 25-60 SCFM, expected pressure drop 2-5 PSI, gas methane, temperature 150 degrees F

Thank you very much for any help you can lend.
John C

[Steve McGahey]

Masonellian (a major valve manufacturer) put out a valve sizing handbook which would likely be of use for you.

http://www.masoneila...d...id=1555&a=0



Fischer Control Valve handbook

http://www.chemicalp...trol_valves.pdf



Here's another link I stumbled across (general reading)

http://www.iceweb.co...trol_valves.htm

[Padmakar Katre]

Hello sir few days back i downloaded one article from cheresources regarding valve sizing and selection please find the same

[proinwv]

I believe that the best resource for these questions is the ISA www.isa.org

and their publication, S75.01, can be found at

http://www.isa.org/T...&Productid=5856

As to the post by Padmakar I suggest that it does not deal with compressible flow and furhter deals lightly with choked liquid flow.

[proinwv]

and I forgot to mention, I would be surprised that a control valve could possibly keep up with the speed required for this application. A pressure regulator (PRV) would be more appropriate.