Temporary solution for undersized condensate piping? 3

[YungPlantEng]

Condensate piping used to heat 6 coils for a sulfur tank is undersized to where startup heating loads hammer and destroy smaller sections of the pipe. It’s currently cost prohibitive to replace everything - are there any effective stop gaps that we could try after shutdown or during startup to mitigate this issue?

During cold weather startups we try and open bypass manual valves to atmosphere until we see steam. This sounds degenerate but would it suffice to put up some small automated valves so light shifts aren’t running around in the dead of winter trying to manually open steam valves while the boiler is down?

The piping is also plumbed in a way that condensate lines move up vertically before going into the main steam header. Not sure how much condensate sitting in the tank coils and blowing through on startup are affecting the hammer we see.

 

[hacksaw]

You need steam not condensate to heat and maintain liquid sulfur!

 

[MJCronin]

Q1: Could we see some sort of "hand drawn" PID or something similar ? .... Are there ANY plant records at all ?

----- I know that this is a stretch, but do you have any idea at all about the piping sizes or steam flow rates ?
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Q2: Do you have any steam traps on the system, what do they look like, and are they functioning ?
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The typical convention is to call the piping that delivers live steam to a device as "STEAM PIPING" and the piping that removes condensate from the device as "CONDENSATE PIPING" ... Just so that we are on the same page here ....

Steam and condensate systems that are designed and installed without competent engineering are notorious for dangerous and DEADLY waterhammer events !!!

You ask: "would it suffice to put up some small automated valves so light shifts aren’t running around in the dead of winter trying to manually open steam valves while the boiler is down?"

Yes indeed, automatic valves have been in use on steam and condensate systems for decades now ... BUT NOTHING CAN BE DONE UNTIL SOME KIND OF PID IS DEVELOPED !

I assume that you live in part of the undeveloped world where there are no cell phones ... otherwise you would post pictures ...



MJCronin
Sr. Process Engineer

 

[mk3223]

First, how often the sulfur line of the Plant is to shutdown and start up? Normally, the steam/condensate line is running continuously to keep sulfur line flowing all the time.

It's typical that the vertical condensate riser is always full of condensate water after the steam trap which is located at the end of the steam coil. During the normal operation, the deferential pressure of steam and condensate should push the condensate up to the overhead return header and to the vessel.

To make sure to have separate condensate piping for the steam lines with different pressures. otherwise, the lower pressure of the steam/condensate system won't be able to provide enough heating as needed for the sulfur lines.

 

[LittleInch]

Reading between the many lines here it sounds like their boiler breaks down often and the steam lines then condense and leave condensate / water all over the place in the steam system.

Of course we have no details to use, but it sounds to me like they need to go through a set procedure to drain and then slowly refill all the steam lines with steam carefully blowing the condensate out.

Are the condensate lines you talk about from a condensate trap?

Steam systems like this are simply not designed to start and stop, for the reasons you describe.

Fix the boiler is the solution...

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[georgeverghese]

"Not sure how much condensate sitting in the tank coils and blowing through on startup are affecting the hammer we see."

Well, that is what is causing the hammer - a big slug of cold condensate meets steam, resulting in shock local depressurisation.

Agreed, find a way to dump this cold condensate accumulated in the coils elsewhere on startup.

Dont you get hammer in the exit lines even during normal operation as cold condensate hits the steam in the main header? Steam condensate is usually routed back to the boiler vis dedicated condensate return lines and not through a live steam header.

Bad design if you ask me.

 

[pierreick]

Hi,
I've seen reactors/Crystallizers equipped with a single coil/jacket where at the end of the cooling step the system was flushed with Air/N2 to get rid of cold water prior to the start-up of the next batch and heating up the chemicals with steam.
This requires on/off valves +PLC.

Pierre

 

[Joe591]

Are you sure its your condensate piping that is undersized and not the steamtraps? What kind of steam traps do you have and have they been placed at strategic points. More importantly, when last did you do a steam trap audit, i bet half of them arent working anymore. Like if you have a spot where your steam pipe goes vertically upwards you should have a drop pocket with a steam trap station before the vertical part. Otherwise you are bound to get waterhammer.

 

[YungPlantEng]

I think nearly everyone took a grammatical error and ran with it no we don’t use condensate to heat steam piping the condensate return header is the issue in our steam heating system for our molten sulfur nozzles.

Last trap audit was 6 months ago. The traps themselves are correctly sized. We don’t hear hammer in regular operation. Since we only fail piping during cold weather events or startup events the conclusion is the vertical coils that can’t be purged of condensate are causing this issue.

 

[LittleInch]

"the conclusion is the vertical coils that can’t be purged of condensate are causing this issue."

Exactly - you've answered your own question.

Now the trick is how to drain the vertical legs so that there isn't any condensate when you start up.

We can't help or fix that as you've not given us any information with which to help you.

Perhaps you need to add some more steam traps.
Perhaps you can blow through air?
perhaps you can't do anything other than run through a set start up procedure.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[hacksaw]

Basically your system needs a complete redesign.