Performance Analysis of Oxygen Transport Reactors

This study aims at investigating the performance of a cylindrical ion transport reactor designed for oxy-fuel combustion. The cylindrical reactor walls are made of dense, nonporous, mixed-conducting ceramic membranes that only allow oxygen permeation from the outside air into the combustion chamber. The sweep gas (CO2 and CH4) enters the reactor from one side, mixes with the oxygen permeate and the combustion products are discharged from the other side. The process of oxygen permeation through the reactor walls is influenced by the flow condition and composition of air at the feed side (inlet air side) and the gas mixture at the permeate side (sweep gas side). The modelling of the flow process is based on the numerical solution of the conservation equations of mass, momentum, energy and species in the axi-symmetric flow domain. The membrane is modelled as a selective layer in which the oxygen permeation depends on the prevailing temperatures as well as the oxygen partial pressure at both sides of the membrane. The CFD calculations were carried out using FLUENT 12.1 while the mass transfer of oxygen through the membrane is modelled by a set of user defined functions.