Predicting Performance of a Condenser With Plugged Tubes

The electric power generated in a steam-power plant depends on condenser pressure. Plant performance personnel are frequently called upon to predict effects on megawatts generated and plant heat rate as condenser circumstances vary. The flow rate of circulating water to the condenser is one of the factors that impact the results when doing such predictions. This paper utilizes the PEPSE modeling program to evaluate the effect on the condenser back-pressure and power generation of plugging condenser tubes. The circulating water flow rate is the focal point of this analysis because it influences the heat transfer coefficient inside of the tubes of the condenser. This inside-tube convection heat transfer coefficient is an important contributor to the calculated overall condensing heat transfer coefficient and the resulting condenser pressure. Calculation of the condenser’s shell side pressure is based on the Heat Exchange Institute’s (HEI) methods that are standard in the industry. In operation the circulating water’s flow rate occurs at the point where the head of the circulating water pump balances the hydraulic pressure drops in the circuit. Equations are presented to account for circulating water pressure drops, as foundation for calculations of the hydraulic balancing. The equation methodology is then applied to an actual condenser design.