5.2 Avoiding condensate contamination

One of the key benefits of recovering condensate is that it is pure water and as such does not require any treatment before it is used as boiler feed water. However, steam condensate can become contaminated with process fluids or other utilities under certain circumstances. This contamination can occur due to equipment failure, leaks, or cross contamination when multiple utilities like cooling water, brine, etc. are used in the same heating/cooling space in a process equipment. Contaminated condensate cannot be used as boiler feed water as it can cause damage to the entire steam system including the boiler.

In industries such as pharmaceutical, chemical, tyre and edible oil, fear of condensate contamination is a valid concern and often a cause of poor condensate recovery.

In many cases contamination can be avoided by addressing the following:

Prevent the occurrence of equipment failures and leaks:

A frequent cause of equipment failure or leaks leading to contamination is the damage caused by water hammer, which occurs when condensate accumulates in the steam space within equipment, steam coils, or Plate Heat Exchangers (PHEs). Selecting the correct type of steam trap and sizing it to cater to the startup and running load, ensures complete condensate evacuation and prevents equipment
failure or leaks due to water hammer.

Detect and address leaks:

Take immediate action to identify and fix leaks in PHE gaskets and coils that can lead to contamination. Implement leak detection methods such as sensors, pressure monitoring or visual inspection to identify and locate leaks. Installing pH or conductivity sensors in each section or block in the plant can help monitor the quality of condensate, making troubleshooting easier and enabling precise identification of the contamination source.

Segregate utilities:

In equipment where multiple utilities are used in the same jacket, cross contamination between utilities can occur. This is because complete drainage of utilities is not possible, and some traces of the previous utility remains behind in the jacket. When steam is introduced, remnants of the previous utility mix with the initial condensate formed, contaminating it. Most plants drain such condensate. However, it is possible to recover condensate from these equipment too without any risks. This can be done based on temperature, conductivity and pH measurement of condensate. For example when steam condensate mixes with remnants of other utilities like brine, chilled water or cooling water in the jacket, its temperature drops. This low temperature contaminated condensate is automatically segregated and not recovered. Once the equipment starts discharging pure condensate, its temperature increases (corresponding to the steam supply temperature) and this condensate can be recovered.

A Multi-Utility Process Trap enables this segregation preventing contamination of condensate at source and thereby enabling recovery of condensate from such multi-utility equipment.

Figure 9: Multi-Utility Process Trap