Synthesis, formulation and spray-drying of mixed oxides for the Chemical Looping Combustion process (CLC)

Diogo Lopes de Oliveira

Key information

Authors:

Diogo Lopes de Oliveira (Diogo Lopes de Oliveira Marçal)

Supervisors:

Mathieu Michau (Mathieu Michau); José Manuel Félix Madeira Lopes (José Manuel Félix Madeira Lopes)

Published in

09/21/2012

Abstract

In the context of growing concerns with earth's climate changes, it is urgent to minimize CO2 emissions. In order to do so, one combustion technology seems to be very promising. Chemical looping combustion (CLC) is an oxy-combustion associated with inherent separation and capture of CO2 with a low energy penalty. From a general point of view, CLC refers to a process where a chemical reaction takes place within two different reactors, and a reactive solid material circulates between both reactors to drive this chemical reaction. Within IFPEN CLC units, the process requires use of an oxygen carrier elaborated in the form of coarse particles, generally composed by synthetic products. The scientific approach developed in this work is based on physico-chemical interactions between an active phase and an inert mineral binder within the final material (microspherical particle). The active phase may correspond to various metal oxides and in our case the inorganic binder corresponds to an alumina sol (peptized Boehmite). To this purpose, spray-drying technique was studied, as it is a method well suited for preparation of particles with high sphericity. Other unit operations such as synthesis, filtration, washing, milling, calcination and sieving were used to test four different raw materials. One of the main conclusions of this work is that formulation, rheology and atomization parameters determine size, morphology and texture of particles. It was concluded that we could increase the size of the particles and decrease the existence of microstructural defects with the augmentation of viscosity.