ABSTRACT

The Power Industry has traditionally focused on base load conditions. In the past, as utilities were operated at or near base load, part load operation was neglected. Most modern day plants, however, can expect frequent operation under part load conditions.

These events have led to a new awareness of the need for adequate venting at off design conditions. EPRI (Electric Power Research Institute) studies have identified the inter-relationship between adequate venting and good condenser performance. This paper will describe the heat transfer effects and interrelationship between venting systems and steam surface condensers, the characteristics of most common venting systems, and a recent adaptation, Hybrid Venting, which combines a steam ejector with a condensate or water cooled intercondenser backed by a liquid ring vacuum pump.

Hybrid systems offer several advantages over existing systems, which are detailed herein. Retrofit of existing liquid ring vacuum pump systems is also discussed.

EFFECT OF NON-CONDENSIBLES ON CONDENSER PERFORMANCE

The importance of proper condenser venting on steam surface condenser performance is not fully appreciated in the power industry. The effect at times is quite profound.

Heat transfer engineers have long been aware of the fact that as vapor is condensed in the presence of non-condensible gases, the condensed liquid film is no longer the primary resistance to heat transfer....

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