Sealing Water for Vacuum Pumps

Question

In kraft paper manufacturing, how should one treat white water to be reused as sealing water for a vacuum system?
And what are the properties of suitable sealing water?

Soloman Prince · Answer

Vaccum seal ring pumps are normally equipped with a Heat exchanger to control the temperature of sealing a water and an arrangement to top up Make up water.We use these pumps to tap the carbon di oxide released from the Multi flash distillers and the moisture seperated is used as sealing water which makes it kind of a closed loop.
You have to see which is the best way to achieve in your system.

David Cifuentes · Answer

I am assuming that you are talking about vacuum pumps on the paper machine.  If you are talking about something in the Kraft Mill itself, then you may be using different types of pumps that I'm not familiar with.
On the paper machine, one big problem with white water will be temperature.  The max temp I've seen for vacuum pump seal water is 32 C.  A 14 C increase in water temperature is not uncommon for the seal water.  For that reason I've only seen fresh water used.  Sometimes, the fresh water is recirculated through a cooling tower to reduce FW usage.  Or, you can use the heated seal water as makeup elsewhere.

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