Control valve vs silencer
Control valve vs silencer
(OP)
Hi,
I have a vaporizer with a constant blow-down to the atmosphere of CO2 and Steam.
The standard design for this blow-down is using silencer downstream of a control valve (attached case 1)
I wondering whether I can use another control valve instead of the silencer (attached case 2) and still maintaining the original performance (noise level of 85 dB).
Is it feasible?
What should I be concerned of?
Blow-down stream properties:
Pressure [bara] 6.9
Temperature [°C] 145.5
Flow [kg/s] 7.5
Water: 60% vol.
CO2: 40%vol.
Appreciate your help.
I have a vaporizer with a constant blow-down to the atmosphere of CO2 and Steam.
The standard design for this blow-down is using silencer downstream of a control valve (attached case 1)
I wondering whether I can use another control valve instead of the silencer (attached case 2) and still maintaining the original performance (noise level of 85 dB).
Is it feasible?
What should I be concerned of?
Blow-down stream properties:
Pressure [bara] 6.9
Temperature [°C] 145.5
Flow [kg/s] 7.5
Water: 60% vol.
CO2: 40%vol.
Appreciate your help.





RE: Control valve vs silencer
David Simpson, PE
MuleShoe Engineering
"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.
RE: Control valve vs silencer
RE: Control valve vs silencer
I am starting to see more and more regulations specifying "how" and they really piss me off because the regulators are effectively killing any chance of a better mouse trap being developed. I worked on the new Subpart OOOO of the Clean Air Act last year for the API an we identified dozens of places where the "how" regulation would result in dirtier air than just telling us the target. Mostly they listened (for once) and we got an awful lot of that garbage exorcised.
David Simpson, PE
MuleShoe Engineering
"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.
RE: Control valve vs silencer
I was trying to let Mike4chemic know that, presuming he was in the US which might be a bad presumption on my part, that there are reasons for silencers and a control valve might not meet those reasons.
RE: Control valve vs silencer
The reason for silencers is to lower noise level. Million ways to do that. The last time I read 1910 it said "what" not "how". The two control valves idea might be an effective silencer since you can set it to adjust for changing conditions.
David Simpson, PE
MuleShoe Engineering
"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.
RE: Control valve vs silencer
RE: Control valve vs silencer
The application is designated to EU power plant. We do have restrictions on the noise level.
I can't do an experiment to check it.
my concern is, whether the pressure drop on the second valve and the release of vapours will cause high noise level.
with the valve vendor's software it looks that i am on the safe side (<80 dB).
Do you have any more suggestions, on how else can i check it?
RE: Control valve vs silencer
RE: Control valve vs silencer
rmw
RE: Control valve vs silencer
a 16" valve say 3 bar drop is not cheap and is likely noisey it self, use a single valve and treat the noise
regs are fine, they're good for business, remember when the noise restrictions first arose in the 70's...everyone thought the end of the world,...
not really, the valve suppliers were delighted...and the valve ended up providing better control with longer life,
we had a valve in a plant designed in the 50's, it went through 30K of inconel trim every month! OSHA noise restrictions did not exist when designed,
since when did engineers start complaining about "homework"
RE: Control valve vs silencer
I am still concerned about the high velocity flow through the blow-down pipe to the atmosphere.
What do you recommend the vapours' max velocity criteria of design should be, to avoid the noise restrictions?
RE: Control valve vs silencer
the deltaP/P at each valve must be held less than 0.5 with the fluid mach number at each valve exit held less than 0.3...
your valve supplier, will advise as to the generated noise in the valves and you'll have to consult the vent silencer supplier as to un-treated vent noise
we expect a full report of your piping and valve cost options next week...