The deaerator is a key, yet oftentimes overlooked, component of the steam generation cycle, regardless of the scale of your process. Whether it is part of commercial power generation or a packaged boiler system, the deaerator has a crucial role to play.
Although serving a primary role of removing noncondensable gases (O2 and CO2) from boiler feed water to prevent corrosion for improved hardware longevity, the deaerator also provides additional support functions which, along with its core benefit, require high-quality instrumentation with accurate level controls to ensure optimal performance in its assigned tasks. Here are some of the support functions that deaerators provide:
- Preheating boiler feed water for improved efficiency
- Reduces fuel requirements
- Effective removal of dissolved gases (O2 and CO2) from boiler feed water
- Minimizes corrosion for improved hardware longevity
- Ensuring adequate head pressure for boiler feed pumps
- Increases hardware longevity/lowers maintenance
- Managing deaerator storage/inventory
- Ensures sufficient supply to meet steam production demands
Level Measurement Challenges and Considerations
As with all level measurement, the first obstacle is working around the effects process dynamics have on the fundamental technology. Another difficulty is the complexity of the measurement system relative to hardware installation, software corrections and its perpetual need for calibration. Eliminating variables in the level measurement equation is the easiest method of optimizing your DA level.
Furthermore, inadequate level controls can inhibit the deaeration process. If the level is too high, this prevents the temperature from meeting minimum requirements for removal of dissolved O2 and CO2. On the flip side, if the level is too low it can reduce or shutdown feed water flow to the boiler, affecting end use steam needs. The former affects hardware longevity and efficiency, while the latter risks production losses and possible damage to pumps.
We don’t want to ignore the fact that any appreciable gain in boiler feed water achieved by leveraging the heat exchanger aspects of the deaerator reduces the amount of fuel required at the boiler— every 10.8 °F (6 °C) rise in boiler feed water amounts to a one percent savings in fuel cost.
Level Measurement Solutions
MAGNETROL addresses the measurement challenges of DA level control with several instrument options:
- For point level
Model B35 external cage float-actuated switch for low level alarming, ASME B31.1 construction
- For continuous level
Eclipse® Model 706 guided wave radar transmitter for aggressive steam application
- For visual indication & continuous level
Atlas™ or Aurora® magnetic level indicator with integrated guided wave radar can be supplied with switches
For more information on solutions for your DA level control and other power/steam generation applications, download the power industry brochure. You can also download the steam generation apps brochure for more information on level solutions for the steam generation and condensate recovery process.