UNIQUE VACUUM PROBLEM

[rajankanwar]

We are operating a surface condenser of 45 MT/Hr condensing duty attached with a steam turbine. The condensing operating vacuum remained quite low i.e 0.60 ata against design of 0.14 ata. The cooling water flow through the condenser appears to be normal. The condenser shell has expansion bellow on one end. On recent inspection, we found some gap in the air-cooling section baffle plate (Shrouding the air cooling bundle) near expansion bellow. It is suspected that air/inert ingress through this gap is responsible for poor vacuum. The gap is across the expansion bellow,
Kindly suggest how to seal the gap as the inert plus steam directly bypasses the surface condenser tube bundle thereby creating a additional load on two stage ejector system.

Er. Rajan Kanwar

 

[Montemayor]

rajankanwar (Chemical):

Your basic data is confusing. First you mention a water-cooled condenser; then, you mention an air-cooling section baffle. Which is it that you have?

Perhaps you have both, connected in series. Is this right? Which is first? How is the the "baffle plate" constructed?

Although this is difficult to visualize and probably more difficult to describe, could you be more liberal with your information?



Art Montemayor
Spring, TX

 

[rajankanwar]

The surface condenser has an air-cooling section inside. A portion of tube bundle is kept separately for inert/air cooling. This portion is shrouded by a welded plate. The steam plus inert/air enter the condenser from top and steam condenses as mixture travels down wards. The air rich mixture then enters the air- cooling section of the condenser (From bottom gap in the Shroud on air cooling tube bundle). We have observed a gap in the air- cooling section top and suspects that direct bypassing of seam instead of air is overloading the ejector system and subsequently low vacuum. The gap is across the expansion bellow provided on shell. How to plug the gap without inducing much stress on the expansion bellow.

The use of bio duct tape may be an alternative but its specifications and ability to withstand 0.16 ata pressure may be explained little further
THANKS
RAJAN