Lincoln Electric Systems (LES) recently commissioned a membrane decarbonation system using Liqui-Cel® 14x28 Membrane Contactors to remove CO2 prior to their mixed bed deionizers. The system was installed at the Rokeby Generating Station (RGS) in Lincoln, Nebraska.
The Rokeby Generating Station is LES' primary peaking power station, totaling 255 MW and consisting of 3 duel fuel combustion turbines. The existing DI water system consisted of two single-pass, two-stage RO skids followed by a 31 ft3 (0.87 m3) mixed bed deionizer and two 250,000-gallon (943 m3) storage tanks.
LES determined that the mixed bed unit was producing only 30% of its expected capacity (90,000 gallons actual vs. 300,000 gallons expected or 341 m3 actual vs. 1136 m3 expected). It was determined that the cause of the decreased capacity was due to dissolved CO2 in the water, which was overloading the anion resin. As the power capacity demand increased, LES had to act quickly to update their winter contingency plans.