Membrane degassing for removal of oxygen in district heating water

The combined heat and power plant, Kredsløb, converts waste into electricity and district heating. They supply district heating to 330,000 households and is one of the major players in the district heating industry in Denmark. A green transition reflects the value, strategy, and ambition of Kredsløb. Therefore, a solution must be both environmentally friendly, consume a minimum of chemicals and be highly efficient to reach the optimal circuit for energy and district heating.

The plant use make-up water in the form of deionate from purified condensate from flue gas condensation at the incineration plant and the combined heat and power plant. To remove oxygen and other gases, Kredsløb demands an automatic degassing system.

Membrane degasification technology is extremely effective for removal of dissolved oxygen in make-up water and compared to other oxygen-reducing technologies it excels by also reducing other problematic gases such as carbon dioxide and nitrogen.

The solution at Kredsløb consists of a membrane degassing unit type MDU 2-8x80” with 2 contactors and a stepless flow between 5-20 m³/h. The long-term benefit of using MDU is improved water quality in the district heating network as well as significant reduction of corrosion and thus less maintenance on the transmission grid.