2.2.7 Install moisture separators
Wet steam is steam containing suspended water droplets / entrained moisture, and is a concern as it reduces plant productivity and product quality, increases energy
consumption and causes damage to equipment and pipeline accessories.
While strategically located drain pockets and steam traps will remove condensate formed in the steam pipelines, they will not remove water droplets suspended in the steam. To remove these suspended water droplets, moisture separators are installed in the steam pipelines.
The moisture separator consists of baffles. Moisture entrained in steam collides with these baffles, and due to drop in velocity, gets separated from the steam and needs to be evacuated using a thermodynamic steam trap.
Moisture separators should be installed at the following locations in the steam distribution network:
- After the boiler main steam stop valve
- Before critical process equipment where wet steam can damage the equipment. e.g. ejectors where wet steam can cause nozzle wear leading to deterioration of vacuum and higher energy consumption
- Before critical pipeline accessories like PRVs and flow meters which are prone to damage due to wet steam
- Before steam enters a plant building from outside, where condensation is higher due to the difference in temperatures
