(401h) Hydrodynamics of a Pilot-Scale Dual Fluidized Bed Reactor: Cold Model Studies

Calcium looping process is one of the cost-effective ways for post-combustion CO2 capture, utilizing CaO as a sorbent in the carbonator and CaCO₃ for CO₂ regeneration in the calciner. A pilot-scale cold model dual fluidized bed system, designed for this purpose, has been built at Waste-to-Energy Research Facility (WTERF) in Nanyang Technological University (NTU), consisting of a bubbling fluidized bed (BFB) as a carbonator for capturing CO₂ in the flue gas from WTERF and a circulating fluidized bed (CFB) as a calciner for regenerating CO₂ for further storage. The hydrodynamics of the pilot-scale system has been investigated through a series of cold model experiments. The effects of different operating conditions, including gas velocities in loop seals, carbonator and calciner, and solid inventories, on the pressure distribution and solid circulation rate have been studied. The preliminary objective of these cold model studies was to evaluate the feasibility of the design for the development of a hot model for continuous capture of CO2 from real flue gas. The results showed that the changes in the gas velocities resulted in variations in the pressure profile and axial solid holdup in the system. The gas velocities in the calciner played an important part in the total solid circulation rate. A stable operation was maintained throughout the system, determined by a pressure drop between the reactors. The implication of these studies contributes to the development of an efficient hot model for carbon capture and paves the way for the scale-up of calcium looping process for industrial applications.