The Complete Steam Guide

Why is a moisture separator needed in the steam distribution network and where should it be installed?

While a thermodynamic steam trap can remove condensate which has physically separated from steam in the pipe, it cannot not remove water droplets suspended in steam. Wet steam can lead to problems in process heat transfer, cause water-hammer and corrosion, and damage process equipment as well as steam system accessories. To remove these suspended water droplets, moisture separators are installed in steam lines.

As per good engineering practices, moisture separators should be installed immediately after the boiler crown valve, before critical steam system accessories like flow meters and control valves and also before steam using equipment.

For example, worn ejector nozzles due to wet steam supply not only impact the vacuum generation but also lead to 15-20% higher steam consumption.

As a general rule, provided the velocities in the pipework are within reasonable limits, separators will be same as the line size. Moisture separators should be properly insulated. If left uninsulated, they will actually increase the moisture content of steam.

Is it necessary to install strainers in the steam distribution network?

Steam lines contain solids like scales or rust which build up over the years within the lines or foreign particles like weld metal. Strainers in the steam lines prevent these solids / foreign particles from damaging in-line equipment.