Posted by Wes on October 23, 2001 at 23:31:31:
In Reply to: Re: water in steam posted by George Larose on October 22, 2001 at 18:08:46:
We found one of the major causes of our carry over.
Our flash tank had started to fill up with scale. The discharge line for the tank was almost completely plugged.
One of the traps on our main steam header dumps into the flash tank so it didn't have any place to discharge.
Constant blow down also goes to this tank so it wasn't working right either.
Water spraying all over the roof when blowing down boiler tipped us off.
Have added PM for flash tank to our system and opening drain valve on flash tank once per shift to keep scale from building up.
If the plant is 30 years old how can all the boilers be over 35 years old
: : I think uninsulated sections of steam line will just give you more load (which will be just waste, in this case). The temperature difference between the steam in the piping and the air surrounding the outside of the pipe will determine the heat loss. If you have bare lines outside, the delta-T can be VERY large, and the volume of condensate formed could easily be more than the line traps were ever designed to handle. You'll have a lot of condensate sloshing around in your steam lines.
: : Things like TDS running way high in boilers will cause carryover. From the way you're describing this plant, I'd be surprised if you DIDN'T have carryover. But a big source of the water in your steam line will be the bare sections of pipe, especially if they run outside.
: : If you can get your hands on a copy of a video by Spirax Sarco, it shows the steam space of an operating boiler. They deliberately do several things (TDS high, operating the boiler at lower than design pressure, off/on feedwater control, etc.) and you can SEE the fog form in the steam space, and disappear out of the steam lead. It's amazing to watch.
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