Boiler steam drum level control is critical in electrical power generation. Too high a level can mean water aspirating into the steam lines and causing damage to the turbine generator blades downstream. Too low a level can cause the boiler to dry and overheat.
In a Power magazine article, Controlling Boiler Level When Operating Conditions Change, Emerson’s Matthew Brummer compares different level measurement technologies for this application. Matthew opens the article highlighting the increasing difficulty of maintaining steam drum levels given constantly changing load demands.
Maintaining this critical level is challenging because a boiler drum is a very turbulent and chaotic place, with high temperature and pressure. Ideally, feedwater should be added at the same rate steam is drawn off. This is manageable when steam consumption is very stable, but when loading goes up and down, level can change quickly.
He highlights the ASME Boiler and Pressure Vessel Code PG-60.1.1. It
…does allow one of those direct-reading gauges to be replaced by two indirect methods of level measurement, which can include differential pressure (DP), displacers, conductivity, or radar technology.
These instruments are typically: Continue Reading ▶
