The concentration of undesirable solids in boiler water can be reduced through the use of a continuous purge or blowdown system. A blowdown tank receives continuous blowdown from the steam drum and blowdowns of variable temperatures and pressures from the steam generator. Boiler blowdown tanks can also function as gravity feed drains for the steam generator when the generator is drained for maintenance.
Maintaining water quality in the boiler within design parameters ensures the highest quality steam possible. By reducing solids, scaling and corrosion caused by water impurities can be minimized and energy recovery can be better facilitated.
Level Measurement Challenges and Considerations
Good boiler blowdown practices can greatly reduce a boiler’s water treatment needs. Combustible mixtures left in a boiler due to improper purges, however, have been known to cause catastrophic explosions. Proper tank level controls are essential to ensure a safe and effective boiler blowdown system.
In addition, optimizing blowdown usage through level control primarily affects fuel economy by better managing the amount of energy required to produce high quality steam for any given task. The performance of any level technology relative to instrument induced errors, calibration nuances, and vulnerabilities to process dynamics can have an immediate and adverse impact on fuel consumption. Seamless response to changes in demand and reducing maintenance associated with the instrumentation or damage to hardware are residual benefits that have their own financial ramifications; these aspects should also be considered when implementing any technology.
Level Measurement Solutions
Magnetrol® has developed level instrumentation for boiler blowdown tanks in response to these challenges:
- Eclipse® Model 706 guided wave radar transmitter with 7YS steam probe
- E3 Modulevel® displacer transmitter
For more information on solutions for boiler blowdown tanks and other power/steam generation applications, download the power generation brochure. You can also download the steam generation applications brochure for more information on level solutions for the steam generation and condensate recovery process.