Sensitivity Analysis in the Design of a Packed-Bed Reactor for a Chemical Looping Combustion Process

Chemical Looping Combustion (CLC) is a cyclic unmixed combustion technology that allows the inherent separation of CO2. In CLC, fuel and oxygen are contacted via an intermediate oxygen carrier, usually a metal oxide capable of being alternately oxidized and reduced. In this way direct contact between fuel and combustion air is avoided, thus producing an N2-free, CO2 rich stream. Different reactor typologies and layouts have been proposed for CLC: among them, packed-bed reactors are currently under the spotlight since they can be more easily operated at high pressure with respect to fluidized bed reactors and, moreover, there is no need for a gas/solid separation step in order to ensure that no fines are sent to the downstream gas turbine. One of the drawbacks in using packed-bed reactors is that several reactors in parallel must be used to achieve a continuous supply of a high temperature gaseous stream for the downstream gas turbine. In the present work a one-dimensional pseudo-homogeneous model is used to carry out a numerical analysis of chemical looping combustion process for heat production, using a Cu-based oxygen carrier and methane as fuel. By means of numerical simulations, the effect of main operating parameters such as inlet temperature and time length of each phase on the process performances is investigated.