Steam Turbine Silencer

[Kannn]

Hello

iam planning to purchase steam silencer to install it on the warm up line of steam turbine
The current arrangement is there is a manual gate valve (1.5 ") at the steam turbine body which directs the steam to atmosphere to warm up the turbine

The Manual gate valve is opened gradually till reach around 5 ton/hr of steam to warm up the turbine

pressure before the manual valve = 40 bar g
Temperature before the manual valve = 440 C
Maximum Flow = 10 ton/hr

i got an offer from a silencer manufacture offersing a silencer with an inlet pressure 25 barg
and he replied with the following :
During discharge of downstream valve, the pressure inside of silencer’s diffuser will be never exceed 25 barg. Gas pressure release phenomena will be observed during discharge to atmosphere.

So I need to understand how to calculate the pressure after the manual valve to confirm acceptance of this silencer , because i have another two offers offering silencers with a design pressure 40 bar

your help is needed

 

[mk3223]

So I need to understand how to calculate the pressure after the manual valve to confirm acceptance of this silencer

So, you may ask this vendor to present his calculation to comfirm it. But, the issue is what the actual pressure of the silencer is if the gate valve is wide open, i.e. 25barg or 40barg.

 

[georgeverghese]

Re the concern @mk3223 raises, a possible solution would be install a restriction orifice downstream of manual throttle startup/turbine warmup valve which limits the flow to 10t/hr with 40barg upstream / 25barg downstream.
Even with such a solution, the silencer would still experience 40barg if it were to be mechanically damaged or partially blocked for some reason or other(corrosion/poor fabrication/inadaquate mechanical strength of internal components to withstand high momentum forces etc).

 

[casflo]

When the steam flow reaches 5 Ton/h, is the gate valve completely open?
If the valve is completely open, the present discharge capacity of the vent line will be 5 Ton/h. Installing a vent silencer that has a certain pressure drop, then the steam flow rate will be less than 5 Ton/h.
Therefore, you need to consider besides the noise level reduction and the silencer design pressure, the silencer pressure drop.
If the gate valve is not completely open when the steam flow rate reaches 5 Ton/h, how does it look from the data of the maximum flow of 10 Ton/h, it produces some pressure drop that is the margin you have to specify the silencer pressure drop.
I any case it is not a good idea operate a gate valve in a throttling position.
To help you in the design, I recommend see my paper published in HYDROCARBON PROCESSING August 2019 titled "Specify the pressure drop of a vent silencer", that deals with this topic.