Is dual mode surface/spray condenser operation asking for problems?

[yamoffathoo]

The steam condenser in question is a vertical, four pass, U-tube design with a spray header. The ring steam header is mounted inside of the ring spray header above the centrally hung tube bundle. Both spray and surface condensing capacities are sized for maximum steam flow, they are supplied by the same source of water and are controlled by vessel pressure. The sprays were intended to back-up the coils during unusual pressure transients, therefore, spray controlling pressure is set higher than for coils.

Tube plugging has reduced coil efficiency to the point where we are seeing simultaneous, extended periods of dual mode operation. What would your concerns be, if any?

 

[rmw]

When I think of steam and sprays, I think of cutting of materials. Could it be that the operation in the past has cut enough tubes so that you have had to plug a number?

If so, your cutting will accelerate with constant spraying into the condenser.

rmw

 

[yamoffathoo]

Through-wall tube cracking adjacent to the seal welds has been the reason for tube plugging to date. I raised a thread previously about this phenomenon and argued that it was caused by large cooling flow oscillations.