4 replies to this topic

[afi]

Dear Sirs;
I want to know that it is possible to take hand control valve as a blowdown valve in petrochemical plants?

thanks

[fallah]

'afi', on 23 May 2010 - 07:35 AM, said:

Dear Sirs;
I want to know that it is possible to take hand control valve as a blowdown valve in petrochemical plants?

thanks

No,because of need to fast action and need to activation from location out of fire zone.Also because those valves are normally closed,on-off control valves to be applied.

[Shubhasis]

Hi,

As per my opinion and experience hand control valve (globe valve) could have been used for blowdown valves. As pressure drop is very high in globe valves which can kill the stream pressure (espcially condensate lines) to a great extent and help to achieve blowdown successfully. I'm presently working in detail design of SRU and we are using globe valve for blowdown of high pressure condensate (40 kg/cm2) to low pressure (3.5 kg/cm2. At the downstream of blowdwon valve there should be one angle valve which pursue the blowdown consistently with change in line sizes. But this may not be the case for larger dia pipes as globe valve sizes would be very big.

I want more expert opinions on this......

Many thanks,
Shubhasis

[fallah]

'Shubhasis', on 24 May 2010 - 04:28 AM, said:

I'm presently working in detail design of SRU and we are using globe valve for blowdown of high pressure condensate (40 kg/cm2) to low pressure (3.5 kg/cm2.

Above mentioned Hand CV would be applied for cold depressurizing.How is your procedure for "Emergency Depressurizing"?

[Nikhiln]

Afi,

I think you should clarify which blowdown you are talking about. It is clear that Fallah is talking about blowdown in the context of depressuring a system, either controlled or emergency. Whereas Shubhasis seems to talk about intermittent steam condensate/BFW blowdown from a steam drum. Both the answers would be correct depending on which one you are referring to. Depressuring systems are usually not hand-controlled as Fallah pointed out. Whereas, condensate blowdown is no big deal for a hand-controlled one, unless the lines are big, as Shubhasis pointed out.

Edited by Nikhiln, 24 May 2010 - 04:56 AM.