Troubleshooting Surface Condenser Venting Systems
ABSTRACT
In an ideal situation, the condensing pressure achievable in a steam surface condenser is determined by the exiting cooling water temperature. However the failure of the venting system to properly remove noncondensible gases from the steam condenser will result in elevated condenser pressures. Information is presented in this paper relative to the most common venting systems available, as well as providing procedures for troubleshooting each type of system. A description is given of the various operating characteristics, along with narrative discussions of field problems and experiences. Simple visual, audible and physical guides to the analysis of venting system problems are discussed. Power plant operating personnel will be able to utilize this information when investigating steam condenser performance problems. A checklist is provided which can be used to isolate these performance problems.
INTRODUCTION
The condensing pressure achieved in a steam surface condenser is determined by the exiting cooling water temperature if the conditions are ideal. All other factors steam condenser design operate to limit this optimum condition and to raise the condensing pressure, which results in increasing the plant heat rate. Some of the factors which have a negative impact on the condenser pressure include inadequate tube surface area, both vapor and cooling water maldistribution, air inleakage, resistance due to tube bundle layout and/or baffle placement, and an inadequate venting system capability. These factors may act independently, or concurrently.