Modeling and design of a calciner for commercial-scale CO2 capture using stochastic methods and results from pilot tests

Carbonate looping (CaL) is a CO2 capture technology with the potential to efficiently decarbonize power plants and carbon-intensive industries, such as cement and lime production. Many pilot tests have demonstrated the feasibility of operating CaL in oxy-fuel and indirect-heating (IHCaL) modes. Still, there is no commercial facility in operation or planning. To support the scale-up of the technology, reliable reactor models are required. However, little progress has been made in calciner modeling in recent years. The available models are either too demanding in terms of computation complexity or lack support from empirical data. In this work, we develop a novel calciner model by combining a particle sub-model with a one-dimensional reactor sub-model. The model is validated with results from experiments in two different pilot plants in the 300-kWth and 1-MWth scales. The predictions of the model are interpreted using stochastic methods and dimensionless numbers. Furthermore, we introduce a three-step approach to designing calciners for CO2 capture. Calciners with oxy-fuel combustion should be operated at 930-965 degrees C to achieve sufficient sorbent regeneration. For indirectly heated calciners, an operating temperature of 950 degrees C is necessary for high performance, but lower temperatures (e.g., 900 degrees C) are also possible using steam for fluidization. Considerations regarding particle residence time are also discussed. Our guidelines are straightforward and enable the design of a calciner with simple calculations.