The hotwell is an important part of the turbine cycle and plays a role in determining the overall operating cost of a power plant as well as its ability to respond to fluctuations in electricity demand. It serves as a water reservoir for steam condensate coming from the condenser – a valuable resource when considering the cost associated with the treatment of make-up water.
The primary function of any level technology employed on the hotwell is to ensure an adequate supply of condensate is available for the boiler to meet current generation needs. This allows the plant to address any shortfall in the supply of make-up water in a timely and efficient manner. Inaccurate reporting of level due to instrument-induced vulnerability to process dynamics or calibration errors can, in extreme circumstances, curtail a plant’s responsiveness to market demands.
In addition to its primary function, hotwell level controls facilitate the routing of excess condensate to the appropriate storage/overflow vessels as well as protecting expensive hardware due to low level conditions.
Level Measurement Challenges and Considerations
The greatest challenge associated with reliable and accurate hotwell level control is a technology’s vulnerability to process dynamics – specifically swings from a partial to full vacuum that can be experienced in the hotwell. Calibration also plays a role in determining an instrument’s performance and cost of ownership. Lastly, air in leakage resulting from ineffective isolation of the instrument in all process extremes, although subtle, does impact condenser efficiency.
Level Measurement Solutions
MAGNETROL’S level measurement solutions eliminate the aforementioned challenges as they relate to reliable and accurate hotwell level control:
- Continuous level: Eclipse® Model 706 guided wave radar transmitter or E3 Modulevel® liquid level transmitter
- Continuous with visual indication & redundancy: Atlas™ or Aurora® magnetic level indicators
- For point level: Model B40 float-actuated switch
Our applications brochure for the power industry details measurement challenges and solutions for critical applications throughout the power generation process. This blog post is part of an occasional series exploring each application in detail.