Fwd:Vibration from flashing valve

From: <Paul>
Date: Wed Jun 26 2002 - 23:16:00 EDT

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Subject: Vibration from flashing valve Author: KV Ravichandran
Date: 6/25/02 8:55 AM

Hi,
Can any one give guidelines for quelling vibrations from flashing control valve.
This is my problem
There is in one 8" Zirconium line carrying acetic acid/ catalyst from reactor
to flash tank. At the flash tank side the line has one flashing control valve ,
gate valve and a conical expander section of about 4.6m long where the pipe dia
increases from 10" to 26" and connects to the flash tank eccentrically.The source of vibration is the flashing control valve (shear stream ball valve)which
throttles from 26 bars to 2 bars. The liquid flow velocity is about 8.5m/s at
the valve.Operating temperature of the line is 193 deg C. During the original design two phase flow and vibration was considered and the
line is supported with TICO Vibration isolation pads and U bolt clamps.

Now the platform from the flash tank as well as the structure supporting the piping near the flashing valve is vibrating.

To have an idea about the magnitude of the vibration following is the latest measurements at the flashing valve.

Fcy      Velocity
Hz       mm/sec
4.405       1.418
8.811       1.049
13.22       .6426
22.03       .6278
48.46       1.876

Thanks in advance

Regards,

K.V.RaviChandran
Senior Piping Engineer
Foster Wheeler Eastern Pte. Ltd. Received on Wed Jun 26 23:16:00 2002