CFD Simulations of a Chemical Looping with Oxygen Uncoupling System: Aiding in Reactor Design

Chemical looping with oxygen uncoupling (CLOU) is a carbon-capture technology that utilizes a metal oxide as an oxygen carrier to separate oxygen from air. The metal oxide oxidizes in an air reactor by the air used to fluidize the reactor and is transferred to another reactor where releases gaseous O₂ into a reactor where fuel, such as coal, is fed. The reduced oxides are then transferred back to the air reactor, completing the loop. Previous experimental and simulated work has been performed on systems less than 1 MW. CLOU kinetics have been introduced into a CLOU dual reactor configuration. These simulations have been used to explore the effects of fuel properties, process properties, and combustion kinetics.

From these simulations design changes to the reactor have been explored including decreasing fluidization volumetric flow rate, altering fluidizing gases, inclusion and design of a carbon stripper. The fluidization volumetric flow rate needed to be decreased proportional to the volatile content of the fuel, this is to maintain proper fluidization regime. The fluidizing gases in the air to fuel reactor loopseal needed to maintain high enough oxygen content as to not introduce oxygen uncoupling in the loopseal resulting in decrease in oxygen transferred to the fuel reactor. From simulations a simple carbon stripper was designed to be used in the system.