CCUS Campus at RWE’s Innovation Center

The amine-based CO2 capture pilot plant at Niederaussem was commissioned in 2009 and has been operated 24/7 for >115,000 hours by RWE’s R&D team. The plant treats 1,550 kg/h of flue gas from a 1000 MW lignite-fired power plant, to capture 7.2 t CO2/d at a capture rate of 90%. The capture pilot plant can alternatively be supplied with flue gas from a conventional wet limestone flue gas desulphurization plant (FGD) or from a high-performance FGD, which also includes a wet electrostatic precipitator (WESP). The performance of more than 20 different emission mitigation technologies (water wash, double water wash, acid wash, dry bed (OASE aerozone®), WESP, two pretreatment technologies) can be tested. Tests comprised the analysis of the effects of ageing of the benchmark solvents CESAR1 and MEA elevated CO2 capture rates (90-99.9%), elevated O2 content in the flue gas (5-16 vol.-%), dynamics of emission mitigation (start/stop behaviour, load changes). The O2/CO2 concentration in the flue gas can be varied by addition of air or the exhaust gas from a genset (diesel engine, 250 kW) to the flue gas. The capture pilot plant at Niederaussem can be temporarily equipped with various solvent management systems. A particle filter and a carbon filter can be activated in a bypass stream of the lean solvent to the absorber. Longtime tests of different solvent management strategies have been carried out (anion exchange, removal of NO2 by flue gas pretreatment with thiosulfate/sulfite solution). The compressed and liquefied CO2, which can be used in pilot plants for synthesis of efuels and echemicals, has food quality and needs no further purification (>99.98% (v/v)). The capacity of the storage tank for liquefied CO2 is 18 t (pressure 16.5–17.5 bar(a), temperature: minus 26.5 °C), which allows continuous operation of CCU synthesis units. Alternatively, gas bottles can be filled with CO2 to supply utilisation projects. The plant is equipped with around 300 online measurements.

The CCU Campus at Niederaussem has been used for research on all aspects of CCUS comprising: capture technology (solvent development, solvent management, emission mitigation, energetic performance, dynamic behaviour, material qualification, testing of measurement technologies, validation of models on thermodynamics (ProTreat, Aspen), emission formation (aerosol, volatile) and prediction of operational behaviour; compression and liquefaction (trace compounds in the liquified CO2 for transport and storage, measurement technologies), utilisation (demonstration of thermochemical (methanol, dimethyl ether) and electrochemical (methanol, formic acid) synthesis of compounds from CO2. 

The capability to realise 24/7 longtime tests is worldwide unique (e.g. test of the CESAR1 solvent for 34,000 hours without exchange of the solvent inventory). The existing infrastructure to couple demonstrators on CO2 usage with the capture plant generally reduces significantly the effort for testing innovative technologies in an industrial environment.