(602c) Fluid Dynamic Evaluation of Circulating Fluidised Beds for Carbon Capture

Carbon capture by adsorption in amine-functionalised solids has the potential to become a less energy-demanding alternative to the conventional amine scrubbing. Such solid sorbents present higher CO₂ capacity and lower regeneration energy than amine solutions, characteristics that can be exploited using the proper gas-solid contactors to achieve rapid thermal cycling. Circulating fluidised beds (CFBs) are an interesting option in this respect, as they feature the high efficiency in mass and heat transfer of the batch-like fluidised beds and the possibility of handling the adsorption/desorption cycle continuously.

The University of Edinburgh (UoE) and North China Electric Power University (NCEPU) run together the FOCUS (Fundamentals of Optimised Capture Using Solids) project, co-funded by the Engineering and Physical Sciences Research Council (EPSRC) and the National Natural Science Foundation of China (NSFC). The FOCUS project aims to develop a novel process based on CFB technology using supported amine sorbents for post-combustion carbon capture in coal-fired power plants. Lab-scale CFBs are being constructed at the UoE in order to study the fluid dynamics of the process. Experiments are being run to determine a) flow regimes in the different sections of the CFBs, b) operational gas and solid flow rates, and c) gas residence time distributions (RTDs) and solid RTDs using Positron Emission Particle Tracking (PEPT). These measurements will be used to validate compartmental models of the adsorption process and 3-D CFD models of the gas solid flows. Accurate models are required given the stringent purity and recovery requirements of the carbon capture process.