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Frame-V Machine with AA Cooler CW Bypassed
Can AA cooler CW be stopped for 30 min? what are the risks?

Frame-V machine with part load running in gas fuel. A minor leak developed at AA cooler CW O/L line.

My question is: Can i stop the DM water cooler motor, which is supplying to AA cooler? What are the risks?
CPD temp is ~250 deg C.

Some steam will be generated during this time inside AA cooler, and the most important question will it damage the AA compressor?

The leak may get 30 min to attend.

In one line...
when machine is in gas fuel...
can AA be bypassed for 30 min?

1 out of 2 members thought this post was helpful...

bahindra75,

Here's the risks: The inlet air temperature to the Main AA Compressor should NOT exceed 300-325 deg F (approx. 149-163 deg C). The Main AA Compressor spins at tens of thousands of RPM, and increasing the inlet air temperature above the maximum allowable decreases the clearances inside the compressor between the stationary and rotating parts, and decreasing clearances can lead to rubbing and worse, a catastrophic failure. Rubbing can lead to decreased efficiency at a minimum.

By shutting the outlet valve of the cooler you will be trapping water inside the cooler tube bundle. As you rightly noted, steam will develop, probably in a very short period of time. And this steam will likely do two things--increase the pressure inside the cooler tube bundle, and will push steam back into the cooling water inlet (supply) connection. AND, the temperature of the tube bundle will also be greatly elevated, which probably means the seals at the tube nest will not last a long time.

Is 30 minutes too long or just long enough? How old is the cooler at your site? When was it last refurbished or replaced? Has it always had the temperature regulating valve adjusted and working properly? These are things we can't know and can't estimate.

Those are the minimum risks. The choice is yours. At low load (you didn't say how low), it might be okay. But, what if you can't complete the repair in 30 minutes or less? Does the risk increase with time--possibly exponentially? Can you run without a Main AA Compressor if it fails? Can you run without an AA Precooler if it fails--you DO NOT want coolant to leak into the shell side of the cooler, because you DO NOT want liquid to enter the inlet if the Main AA Compressor, which is also NOT good for the compressor. Do you have a spare cooler, or a spare Main AA Compressor?

That's about all I can offer. These are the risks Managers need to know about, to make their decisions. Only they can know the level of risk they, or the owner(s) are willing to take (the lost production; the cost). And that's why they get paid the big bucks: to understand the risks and make these decisions. Often times they are right. And sometimes they are not. But they at least need to understand all the risks, take the condition of the equipment into consideration along with knowing what spares the site has--as well as the possible cost to production and lost revenue, particularly if the power is necessary to operate a nearby plant (fertilizer plant; cement plant; refinery; chemical plant; paper mill; etc.).

@ CSA
I really dont know how to express my thanks and gratitude to you.
We are really fortunate that someone like you is always available to us and convey the invaluable feedback regarding various unplanned situations.

Kudos..
hats off...

Thank you our beloved CSA.

1 out of 1 members thought this post was helpful...

barindra75,

Sorry for not catching the spell checker/corrector mistake on your name on my previous post. I've now completely disabled it (the spell checker/corrector).

Thanks for the feedback and the kind words.

Now if we could only understand why someone clicked on the 'Thumbs-down' (Not Helpful) icon, that would be great. (I get it that some people don't want to understand the "background" of processes and configurations and just want a "simple" answer. But, for things like this--there are NO simple answers. There is risk, and there is informed risk. I prefer informed risk. Of course, I can't be held accountable for any recommendations I make on control.com, since few people know my real identity. So, I could make any recommendation. But I like to sleep well at night, and by providing as much information as possible leave the decision-making to others who get paid a lot more than I do to make choices like this I can continue to sleep well at night. I would just like if people who clicked on the 'Thumbs-down' icon would say why they found the post not helpful. Maybe there's something that could be done to improve future posts. But, it's not my problem if they don't want to express their opinion. I'm just lucky my pay isn't affected by the number of 'Thumbs-down' or 'Thumbs-up' clicks--since I don't get paid for posting at all! Aren't I lucky!?!?)