Remove oxygen and carbon dioxide without chemicals using membrane degassing units

Membrane degassing unit for removal of dissolved gases from water


Membrane degassing units (MDU) provide an efficient, compact, and maintenance-free technology to remove carbon dioxide and oxygen from water without any chemical treatment.

In many high purity and industrial applications - such as boiler feed water, power generation, pharmaceuticals - membrane degassing units have become the standard technology for removing CO2 and O2 from water. For example, carbon dioxide and oxygen removal can prevent corrosion on boilers and piping to protect capital investment, extend life time of equipment, and reduce operating costs. Removing these gases can also improve the process efficiency, e.g. for EDI performance.

Key benefits for selecting membrane degassing units:

  • Chemical-free solution.
  • Small footprint.
  • Low installation costs.
  • Modular design with high flexibility for meeting future capacity or tighter requirements, even after initial installation. 

EUROWATER offers membrane degassing units both as standard add-on kits as well as individual solutions.

 
Standard add-on kits for removal of carbon dioxide


Add-on kits for removal of carbon dioxide (CO2)

Removing carbon dioxide after the reverse osmosis (RO) unit and before the EDI unit (or mixed-bed ion exchange unit) reduces chemical usage and increases EDI performance. Less CO2 loading improves silica removal as well. The goal is to reduce the CO2 content before EDI to less than 5ppm. Operation mode is air sweep.

The membrane degassing units are available as standard add-on kits prepared for a wide range of RO units from EUROWATER for both new units as well as existing units.

 
Individual solution: MDUs mounted on larger RO unit.


Individual solutions

The picture shows an individual solution for CO2 removal after RO and before EDI. Two membrane degassing units are mounted directly on a larger RO unit and the result is improved performance of the EDI and low silica content. The application is makeup water for high-pressure steam boiler at a power plant. Operation mode is air sweep.

EUROWATER offers to design and supply individual solutions with membrane degassing units for carbon dioxide and oxygen removal.

See below for more individual solutions...

 
Individual solution for removal of oxygen in boiler water


Removal of oxygen in boiler feed water

Membrane degassing unit in combo operation mode (vacuum pump with nitrogen as sweep gas) for removal of O2 to less than 20ppb according to EN12952-12. A complete frame-mounted solution with control panel and internally cooled vacuum pump. The MDU piping and housings are stainless steel AISI 316.

 
Individual solution for removal of carbon dioxide without chemicals


CO2 removal without chemical pH adjustment

Membrane degassing units provide a clean, maintenance free method to remove carbon dioxide from water without any chemical pH adjustment. The chemical-free solution was the customer's main reason for selecting MDU technology. The RO and the EDI are also both chemical-free solutions.

 
Individual solution for removal of oxygen in pharma application


Removal of O2 in pharma application

The application is removal of oxygen in cold water loop. Mode of operation is combo: vacuum pump with nitrogen as sweep gas. The MDU unit is designed for hot Clean-In-Place (CIP) sanitization, which is a requirement for high purity water (HPW) for United States Pharmacopeia (USP) and European Pharmacopoeia (Ph. Eur.). 

 
Membrane contactor - click for large image


How to remove oxygen from water

The membrane degassing unit uses a microporous hollow fiber membrane to remove gases from water. The hollow fiber is knitted into an array and wrapped around a center tube inside of the housing. During operation, water flows over the outside of the hollow fibers while a vacuum, strip gas, or both in combination, is applied to the inside of the fibers. Because the membrane is hydrophobic it allows direct contact between gas and water without dispersion. Applying a higher pressure to the water stream relative to the gas stream creates the driving force for dissolved gas in the water to pass through the membrane pores. The gas is then carried away by a vacuum pump and/or sweep gas.

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