Poor Condenser performance

[cal6404]

Hi,

We have a large steam condenser that is running poorly!

The problem:

1) the condenser steam inletcontrol valve goes to 100%
2) the condenser fills with water
3) the outgoing water line that is being heated drops in temperature (because the condenser is full of water)
4) When I open the drain valve on the condenser a large volume of water flows out, then the steam control valves goes back down to 20% and the outgoing water line goes back up to set point
5) The steam trap on the outgoing steam side doesn't seem to be passing steam,

Is the steam trap not functioning correctly? Why does it keep filling with water? I would assume its steam trap related.

Any thoughts? Should we replace the steam trap?

 

[georgeverghese]

Do you have sufficient delta p across the steam trap to allow steam condensate to flow out at all times?

 

[LittleInch]

Errr, "When I open the drain valve on the condenser a large volume of water flows out". So how is the water supposed to drain out normally?? This is a condenser so its purpose in life is to condense steam to water, heating your secondary water in the process?? Therefore it needs somewhere to go to do this on a continuous basis.

We need a diagram and a description of how it is supposed to work.

sounds like level control on your water level isn't working too well from the description you've given.

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

 

[Latexman]

Has the condenser run well in the past, or is this a problem with a new installation?

Good luck,
Latexman

To a ChE, the glass is always full - 1/2 air and 1/2 water.

 

[gcastan]

A diagram would be helpful to understand your problem

Gabriel Castaneda, P.E.

http://www.gabcheminc.com

 

[don1980]

Sounds like one of the following: (1) a malfunctioning steam trap,(2) the normal steam-side pressure isn't high enough to push the liquid through the trap,(3)an excessively high pressure in the condensate collection header (downstream of the trap), or (4)an air pocket is trapped in the steam-side of the exchanger.

Start with the easy step - open a vent on the steam side at a high point. Let it vent for a few minutes and see if the problem goes away. If so, #4 was the problem. If that doesn't fix the problem, then evaluate the other causes.

 

[MJCronin]

You are experiencing heat exchanger "stall" .... a common problem where there is an inadequate liquid volume that is upstream of the trap.

Explained here:

http://www2.spiraxsarco.com/resourc...densate-removal/heat-exchangers-and-stall.asp

and:

http://www.tlv.com/global/TI/steam-theory/stall-phenomenon-pt1.html

MJCronin
Sr. Process Engineer

 

[ione]

Which kind of steam trap are you talking about? If your condenser is experiencing stall, you could fix it by replacing your steam trap with a pump trap operated by compressed air or steam. This kind of trap doesn’t need differential pressure between steam and condensate space as a driven force, since compressed air (or steam) is used to evacuate condensate. Pooling phenomena are not prone to occur with such a trap.

 

[gerhardl]

Hello cal6404,

This is a 'classical' steam problem, and as such interesting, so please respond back, even if you already have found a solution.

As indicated in all answers above, the cause is obviously an imbalance between input and output, which could be caused by malfunctioning equipment, wrong layout in piping, wrongly selected, dimensioned, mounted or placed equipment or input and output regulations working against each other.

For a steam specialist this would be fairly simple to sort out as soon as all details are given.

Good luck.