- Heat exchangers are used to cool liquid process media and/or recover the heat discharged by one process to use in others. Typical applications are steam generators or cooling towers in power plants (air-cooled) and process areas in which liquid cooling media are used for high-efficiency cooling with plate and shell-and-tube heat exchangers.
- Temperature exchange among substance flows with different temperatures is carried out through (typically) metallic plates or pipe walls that isolate the flows but allow heat to pass through.
- Wear and corrosion can facilitate breakthrough leaks in plates and walls, leading to cooling medium contamination and considerable damage to the plant. If polluted cooling water is discharged into the local water source, this can result in health hazards and fines for plant operators.
Detecting heat exchanger breakthrough in time
Conductivity changes in cooling water indicate process breakthrough
Cooled steam precipitates as condensate with a high level of purity and therefore low conductivity. Since increased conductivity is an indication of contamination, measuring the conductivity of condensate is a reliable method for verifying that plants are functioning properly and monitoring for process breakthrough.
As a rule, the measuring points used to accomplish this consist of different conductivity sensors connected to several analyzers/transmitters in a control cabinet. But this requires extensive cabling and takes up lots of space in the cabinet.
Memosens digital sensor technology offers a compact, no-maintenance solution: with the SE 615 Memosens conductivity sensor, condensate contamination can be determined within the broad 10 µS/cm – 20 mS range. The very thin sensor with a PG 13.5 connection thread can be simply adapted to the process in-line using a matching static holder (ARI106 or CSS 120, for example) downstream from the heat exchanger at a point where the temperature is no longer high.
All sensors have an integrated temperature detector for correct temperature compensation. When connecting the measuring points to the control system, the compact (12 mm wide) DIN rail mounted MemoRail transmitters reduce the amounts of space and cable required in the control cabinet. And two standard-signal current outputs ensure floating transmission of measured process values and temperature to the PLC.
Return on Investment
- Reliable monitoring of cooling water quality safeguards plant efficiency and reduces the cost of repairs and water consumption.
- Precise conductivity measurement allows breakthrough leaks to be detected and repaired in time, before they cause expensive damage to plants and the environment.
- Using MemoRail transmitters to transmit measurement and temperature values to the control system makes room in the control cabinet and minimizes cabling costs.