Is there a difference in the steam turbine condenser cooling water inlet and outlet flowrates?

 

yawadu,

Unless the steam turbine condenser you are talking about is different from the majority of steam turbine condensers the outflow of cooling water should be almost exactly the same as the inflow. All of the cooling water should pass through the tubes, condensing the steam passing over the outside of the tubes, and exit the tubes back to the cooling water source or some kind of cooling water cooling apparatus (towers; heat exchangers; etc.). The flow might, in some cases, appear to be slightly (very slightly) higher because of the difference in water temperature, but there should not be any appreciable increase in outflow versus inflow--unless for some odd reason condensate is leaking into the cooling water outflow. This should NOT be possible simply because of the difference in pressures of the two systems (condensate and cooling water--condensate would usually be under a vacuum, and cooling water would be at some positive pressure--so it would be difficult for condensate to get into the cooling water.

If there is a leak in tubes or tube nests it would be possible for cooling water to leak into the condensate--but that should be easily and quickly detected by the presence of contaminants in the condensate from the cooling water (salt from sea water or brackish water; chemicals from a closed-loop cooling water system; etc.). If cooling water was leaking into the condensate then it's possible the outflow of cooling water might be less than the inflow--but, again, tests of condensate should quickly detect such a leak.

If you are experiencing differences in in- and out cooling water flow rates it would be helpful if you need more assistance if you posted the flow-rates (in and out), and told us something about the condenser and how it operates. What would be REALLY helpful would be if you would post a P&ID (Piping & Instrumentation Diagram) of the condenser and cooling water system so we could make more comments after review.

Hope this helps!

 

yawadu,

Unless the steam turbine condenser you are talking about is different from the majority of steam turbine condensers the outflow of cooling water should be almost exactly the same as the inflow. All of the cooling water should pass through the tubes, condensing the steam passing over the outside of the tubes, and exit the tubes back to the cooling water source or some kind of cooling water cooling apparatus (towers; heat exchangers; etc.). The flow might, in some cases, appear to be slightly (very slightly) higher because of the difference in water temperature, but there should not be any appreciable increase in outflow versus inflow--unless for some odd reason condensate is leaking into the cooling water outflow. This should NOT be possible simply because of the difference in pressures of the two systems (condensate and cooling water--condensate would usually be under a vacuum, and cooling water would be at some positive pressure--so it would be difficult for condensate to get into the cooling water.

If there is a leak in tubes or tube nests it would be possible for cooling water to leak into the condensate--but that should be easily and quickly detected by the presence of contaminants in the condensate from the cooling water (salt from sea water or brackish water; chemicals from a closed-loop cooling water system; etc.). If cooling water was leaking into the condensate then it's possible the outflow of cooling water might be less than the inflow--but, again, tests of condensate should quickly detect such a leak.

If you are experiencing differences in in- and out cooling water flow rates it would be helpful if you need more assistance if you posted the flow-rates (in and out), and told us something about the condenser and how it operates. What would be REALLY helpful would be if you would post a P&ID (Piping & Instrumentation Diagram) of the condenser and cooling water system so we could make more comments after review.

Hope this helps!

Thanks for the response. The reason for the question is that the flow meter for measuring the condenser cooling water flowrate is installed at outlet piping of the condenser, it is a Once through cooling system. The cooling water is taken from the ocean and recirculated back.

 

In my opinion, the reason the flow monitor is installed at the outlet is because sea water is the cooling medium. If there is a leak it will be detected in the condensate, and the inflow versus outflow on a single pass shouldn't be detectable unless the leak was huge which, again, would be detected by condensate testing or a big mess on the floor.