4 replies to this topic

[CSNK]

Dear All,

I have one query regarding non-condensing steam turbine - used to run a Compressor.
This turbine runs with HP steam and exhaust is LP steam.
My question is that - when i want to find the max. flow from the turbine - what inlet conditions should i take.
And what will be the basis for knowing the max. flow from the exhaust.
Any one can help me on this.

Thanks.

[ankur2061]

chiks,

This is a relief valve forum. Post your query on the "Industrial Professionals" forum.

Regards,
Ankur.

[CSNK]

I want to know the max. flow through steam turbine - as i want to size the PSV in the LP steam exhaust piping.
Sorry for confusion in the query.

Thanks.

[ankur2061]

For any centrifugal compressor the affinity laws apply, which means the following:

N1 / N2 = Q1 / Q2

and P1 / P2 = (N1 / N2)³

where:
N = speed, rpm (1 and 2 represent two sets of conditions)
Q = Volume flow rate, m3/h (1 and 2 represent two sets of conditions)
P = power, kW (1 and 2 represent two sets of conditions)

It is obvious that at the maximum volume flow rate for a given speed and head the power consumption will be the highest which in turn means that if it is a steam turbine driven compressor the steam consumption will be the highest.

Regards,
Ankur.

[kkala]

Following old standard (~1980) for PSV on non condensing steam turbines says:
-Though not mandatory, large non condensing turbines usually have a PSV at exhaust pipe, set at a pressure between 1.1 of normal exhaust pressure and turbine case design pressure.
- Relieving capacity is recommended to be specified by turbine manufacturer, otherwise it should be equal to nominal flow (*)
- Exhaust steam block valve should be "car seal open".
Note (*) Nominal flow is actually maximum flow under normal condition, look at post by Ankur.
Hope it helps a bit.