Removal of slightly poor vacuum in condensing turbines
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This post was last edited by Jingzhiqiu on 2011-7-10 at 10:21. In a condensing turbine equipped with a CO2 compressor, due to poor quality of the main steam and high levels of Na+, scaling occurred; after shutting down the unit for cleaning, when it was restarted, the vacuum level dropped from -0.08 MPa to -0.07 MPa, and the exhaust temperature also increased. There is now suspicion of a leak in the vacuum system, but inspections were carried out at the location where this shutdown was handled, and no issues were found. In this case, can it be determined whether there is a leak in the vacuum system by analyzing the dissolved oxygen in the condensate water? Under normal conditions, what is the dissolved oxygen level in this turbine condensate (it has not been analyzed before)?
The pressure inside the vacuum system is already so low – how much oxygen can it dissolve? This isn’t very feasible, is it? If there is a leak in the vacuum system, it should be a fairly large one; otherwise, it would be difficult to detect. Let’s check which part wasn’t used correctly.
Under normal conditions, there is almost no oxygen in the steam, as oxygen has been removed from the purified water to levels of only 7 PPb before steam generation; therefore, the amount of oxygen in the steam is virtually negligible.