Enhancement of a 300 kWth pilot plant for testing the indirectly heated carbonate looping process for CO₂ capture from lime and cement industry

The indirectly heated carbonate looping process (IHCaL) is a promising technology for decarbonizing the lime and cement industry. Advantages of the IHCaL are the synergy with these industries using same solid materials and the avoidance of an air separation unit (ASU), since no technical pure oxygen is necessary in this capture process. Former pilot tests showed the feasibility of the IHCaL for applications in the power plant sector. However, the integration of the IHCaL into cement and lime plants, as well as the usability of spent sorbents as educts in these processes, has not yet been proven in industrially relevant conditions. In this study, the modification of an existing 300 kWth pilot plant for demonstrating the IHCaL process are described, aiming in accelerating the demonstration in an industrially relevant environment for cement and lime industries. A flue gas circulation system and a solid fueling system into the combustor, allowing the heat generation for the calcination with e.g. waste derived fuels, have been designed and installed. Results gained during the operation with the modified reactor configuration, are presented in order to assess the performance of the new components in the framework of the IHCaL configuration. The external combustor was operated while co-firing propane with either dried lignite or waste derived fuels. The carbonator was fluidized with a real flue gas from the external combustor, having CO2 concentrations between 11 and 18 vol-%dry. The results, obtained within more than 200 h of continuous testing with modified reactor configuration, show a good hydrodynamic behavior and adequate reactor performance, while providing a sound basis for further improvement and up scaling of the technology.