Control of condensate dissolved oxygen in steam surface condenser. Reconstruction experience

Abstract

Dissolved oxygen concentration in the steam turbine condenser significantly influences the failure-free operation of the power unit.Despite the wide range of recommendations and operating experience, there are still condenser working regimes with abnormal dissolved oxygen concentration.Taking into account the importance of water chemistry, there is a need to pay additional attention to the root causes of the described problem.This paper contains the results analysis of the deaerating tests on the full and part loads before and after condenser reconstruction. The main reason for the high dissolved oxygen concentration was determined. After the reconstruction, the average concentration of dissolved oxygen decreased from 174 μg to 22.7. At the nominal load of the turbine, the average concentration before the reconstruction was 99 μg. After the reconstruction, it was possible to reach values of 14 μg, meanwhile the increase in electricity consumption for own needs amounted to 21.6 MW per month.Despite the test codes recommendations, this study methodology involves changing the drainage input and studying its effect on the dissolved oxygen concentration over a wide range of changes in steam turbine loads. This made it possible to evaluate the effect of a specific drainage flow on the dissolved oxygen concentration.