The SCARLET (Scale-up of Calcium Carbonate Looping Technology for Efficient CO2 Capture from Power and Industrial Plants) project is a large and ambitious project to investigate one of the most promising post-combustion CO2 capture technologies, Calcium Carbonate Looping (CCL). The CCL technology combines low CO2 avoidance costs and efficiency penalties with a low environmental impact and the possibility of retrofit for any fossil fired flue gas source. This project focuses on bringing the CCL technology the next step towards maturity.
Results from four long-term CaL test campaigns carried out in the 1 MWth pilot plant at Technische Universität Darmstadt provide a reliable data base for process scale-up to industrial size. The experimental tests were particularly focused on the long-term sorbent reactivity in realistic operating to gain reliable information about the sorbent performance sing hard coal either in pulverized and coarse form as well as pulverized or grained lignite, respectively. During these test campaigns, different sorbents with different chemical compositions and particle size distributions were utilized. During steady-state operation, CO2 absorption rates in the carbonator higher than 90 % and overall CO2 capture rates higher than 95 % were proven under a wide range of parameters, e.g. fuel characteristics in the calciner, solid circulation rates, make-up rate etc. Steady-state operation decarbonizing the flue gas of a 1 MWth coal fired furnace was investigated during 2,400 operating hours of the pilot, thereof more than 1,200 hours with continuous CCL operation.
For a scale-up of the CCL technology from 1 to 20 MWth and finally to 600-100 MWel, reliable design tools to model the whole system were developed and validated against experimental data from long-term pilot testing. Therefore, steady-state and dynamic process models for heat and mass balancing were developed and validated against the experimental data to predict the performance of up-scaled plants. Three-dimensional computational fluid dynamic (CFD) models based on different approaches for detailed reactor investigations and optimizations were investigated.
As the subsequent step towards commercialization of the CCL technology, a scale-up of the process to a 20 MWth pilot plant was carried. The work has been supported by the experimental data in 1 MWth scale and the developed scale-up tools. The design and engineering of reactors and all required auxiliary systems were based process configuration was defined based on heat and mass balances created for various load cases. The design and operational performance of the reactors were confirmed by CFD simulation with different model approaches. The investment cost (CAPEX) and operational cost (OPEX) were estimation. A detailed measurement plan was elaborated to validate the process in the scaled-up pilot plant. Furthermore, the operating procedures were defined describing the control strategy for various operating conditions. The Balance of Plant and the permitting process for erection and operation was prepared including a detailed plan for operation and logistics. Health, safety, environment (HSE) and technical risk assessment have identified no risks that would be considered unmanageable.
The thermodynamic, economic and environmental analyses for various host power and industrial plants based on the validated process model show the great advantages of CCL retrofit in terms of energy penalty, CO2 avoidance costs and environmental impact. A net efficiency loss including CO2 compression in a range of 6-7 %-points (including CO2 compression) for hard coal and lignite fired power plants combined with very competitive CO2 avoidance costs of 20-27 € per tonne CO2 show substantial advantages compared to other carbon capture technologies. Life cycle assessments conclude that the environmental burden of host power and industrial plants can be significantly reduced by a CCL retrofit.
WP4: Integration of CCL into a Full-scale Hard Coal Power Plant (UNP)
WP5: Integration of CCL into a Full-scale Lignite Power Plant (RWE)
WP6: Integration of CCL into Full-scale Industrial Plants (ULster)