Controlling gas levels in the power plant and boiler feedwater systems is very critical to plant operation. It is important to remove both CO2
from water and O2 from water. Both of these gasses are corrosive and they can negatively impact the boiler performance and corrode metals in contact with the boiler feed water. Historically chemical injection, vacuum towers, and/or forced draft deaerators were used to remove oxygen and carbon dioxide
from boiler feedwater. Liqui-Cel Membrane Contactors, however, offer many advantages over these outdated technologies and many plants are choosing membrane systems because they are economical and compact.
Chemical injection often used in boiler maintenance puts excess deposits on metal surfaces. People are also required to handle the chemicals and this is a potential health risk to employees. As chemical deposits accumulate on the boiler surfaces, the boiler has to be shut down and cleaned in a process called blow down. Blow down frequency periods increase when chemicals are injected into the feedwater. As blow down increases, operating costs increase as well because blow down generates a loss of water and a loss of heat in the system that needs to be reestablished after blow down is complete.
Membrane Contactors are extremely attractive to the many industries that rely on boilers for power. Membrane Contactors have 10 times more surface area compared to most vacuum towers and forced draft systems which means they are very small and compact and can be installed inside. Inside installation near the boiler requires less piping and has lower installation costs. Membrane contactors can be run in-line and under pressure. Because there is still positive pressure at the outlet of a Membrane system, repressurization pumps can also be alleviated.
Oxygen removal to 1ppb can easily be achieved with membrane contactors. Compare that to a typical vacuum tower that can only achieve 7ppb. Likewise dissolved CO2 can also be removed to 1ppm. That is also lower than what a typical forced draft deaerator can produce.
in the Boiler feedwater and power industries is also a very important step to protecting piping and equipment. For more technical information on chemical free boiler feedwater degassing, please review the Technical Briefs to the right.
Membrane Contactors: An Introduction To The Technology
This paper provides a good overview to Membrane Contactor technology. Principles of Membrane Contactor Operation and mass transfer principles are discussed.
Membrane Contactors are used as a Boiler Feedwater Deaerator
Read how Membrane Contactors are used as a Boiler Feedwater Deaerator to reduce blow down frequency and chemical usage.
Degasification of Boiler Feed Water with Liqui-Cel® Membrane Contactors
This paper discusses how Liqui-Cel® Degasifiers can be optimized as boiler feed water deaerators for oxygen removal from water and carbon dioxide removal from water. Advantages of Liqui-Cel® systems over conventional deaerators and forced draft degasifiers are also highlighted.