Performance of MEA in a long-term test at the post-combustion capture pilot plant in Niederaussem

RWE Power, BASF and Linde entered into a cooperation in 2007 to adapt the CO2-scrubbing technology for application in power plants and to optimize significantly the technical and economic performance of CO2 post-combustion capture. All aspects of the capture process on the basis of new energy-efficient solvents developed by BASF and the improved plant technology by Linde are investigated in a pilot plant at RWE Power's lignite-fired power station in Niederaussem, Germany. Some 250 measurements and an online-gas analysis system allow a detailed validation of the operational performance of the plant and a precise determination of the energy demand for the CO2 capture process. In extensive accompanying analysis programs, solvent stability and the formation of degradation products and emissions are investigated. Including commissioning, start up and extensive parameter studies, the pilot plant was in operation for more than 5000 h with 30%-weight MEA as benchmark solvent from mid-2009 until January 2010. During this time, all aspects of the optimized process configuration were tested and compared with modeling results and literature data. This paper describes the performance validation approach on the basis of the results of the measurement program (specific energy demand: 3.5 GJ/tCO2) and the investigation of the time-dependence of MEA degradation and organic acid formation under real power plant operating conditions (MEA loss: 0.3 kg/tCO2; after 5000 h of operation weight-related content of acetate: 1.8%, formate: 0.2% and oxalate: <0.1%).

► 5000 h pilot plant operation with 30%-weight MEA.
► Contribution of individual process optimization measures to the specific energy demand of less than 3.5 GJ/t of captured CO2.
► Non-equilibrium simulation model reproduces results of parameter studies within range of experimental uncertainty.
► Degradation of MEA is dominated by oxidative decomposition and formation of acetate.
► Highly non-uniform degradation rate with s-shaped slope of acetate concentration not linked to iron or sulfur concentration.