Modelling and experimental validation of calcium looping CO2-capture process for near-zero CO2-emission power plants (CAL-MOD) : final report

The Project objective is the development of advanced modelling tools required for implementing Calcium Looping (CaL) at commercial scale. In this regard the research focused on studying the optimization of limestone utilization, developing models and investigating the process feasibility. Thus, detailed experimentation at particle level (TGA, lab-scale fluidized bed) and bench scale systems (10 kWth. dual fluidized bed, cold model) provided the required data base. Screening of 7 limestones has identified the best limestones with regard to CO2 capture and attrition behaviour under oxyfired conditions. Spent material with poor chemical properties was reactivated with the goal to increase sorbent activity and process performance. Experimentally obtained data were used for the development and validation of 3-D transient full-loop CFD models (incl. particle clustering effects, EMMS drag scheme application and reactions simulation). Moreover; process design tools to scale-up the process and evaluate process parameters were developed. Therefore a predicative CO2 capture model was implemented into an ASPEN/GateCycle process simulation model and combined with Ebsilon® steam cycle simulations to determine the overall process efficiency for two reference power plants (hard coal and lignite). The results from modelling and experimentation provided the basis to scale up to a full scale plant design including the design of heat exchanging surfaces in the reactors and fluidized bed heat exchangers as well as economic evaluations of the process. Cost of electricity and CO2 avoidance cost of CaL have shown advantages compared to oxy-fuel combustion and amine based technologies. A great potential for utilisation of the purge CaL material for cement production as well for integration of the CaL process in a cement plant has been shown.