Preparation and Characterization of Lanthanum-Promoted Copper-based Oxygen Carriers for Chemical Looping Combustion Process

Abstract

Chemical looping combustion (CLC) is an oxygen combustion process that results in the higher CO 2 concentrations in flue gases. Copper-based oxygen carriers have high reactivity, resulting in high purity CO 2 generation, but face the challenges of low copper melting point and potential thermal sintering under high-temperature cyclic operation. A temperature-programmed reduction and oxidation (TPR-TPO) technique (Redox) was used to simulate of the cyclic operation of copper-based oxygen carriers in the CLC process. Multiple material characterization methods were applied to the fresh and used oxygen carriers, including the determination of pore structure and surface area by Brunauer-EmmettTelle (BET), crystal structure by X-ray diffraction (XRD) and surface phase diagram analysis by scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM-EDX). Thermally stable copper-based oxygen carriers have been successfully prepared using commercially-available Al 2 O 3 as the supporting material and selected additives. A substantial resistance to agglomeration and durability in over 50 cyclic Redox tests under high temperature conditions (oxidation at 800°C and reduction at 800°C) has been confirmed for the Sample labeled as CLCA. The oxygen transfer capability was almost stable, and the CuO content ranged from 20 wt% to 23 wt% for the CLCA sample. The supporting material (Al 2 O 3 ) significantly impacted the oxygen releasing performance and thermal stability of the copper-based oxygen carriers, due to the formation of a new crystal phase (CuAl 2 O 4 ) which cross-links the CuO and the γ-Al 2 O 3 . Lanthanum accelerated the cross-linking between CuO and Al 2 O 3 .

Chemical Looping Gasification of Charcoal with Iron-Based Oxygen Carriers in an Annular Dual-Tube Moving Bed Reactor

“…Cao et al (2014) indicated that the agglomeration of copper-based oxygen carrier was avoided by using Al 2 O 3 as support and promoted by lanthanum. In addition, the formation of a crystal phase (CuAl 2 O 4 ), crosslinking CuO and γ-Al 2 O 3 , was supposedly to contribute to the stability of copper-based oxygen carrier, whereas the lanthanum contributed speeding the formation of the crosslinking between CuO and γ-Al 2 O 3 .…”

Use of Spinel Nickel Aluminium Ferrite as Self-Supported Oxygen Carrier for Chemical Looping Hydrogen Generation Process

“…Additionally, a potential energy conversion technology, chemical looping hydrogen generation (CLHG), was proposed using the chemical looping combustion process integrated with the steam-iron process, which is composed of a fuel reactor, a steam reactor and an air reactor, as shown in Fig. 1 (Jozwiak et al, 2007;Kang et al, 2010;Wang et al, 2012;Cho et al, 2014;Cao et al, 2014).…”

Chemical and calcium looping reforming for hydrogen production and carbon dioxide capture

“…To date, a significant amount of sorbent development work has been focused on complicated and potentially expensive routes for producing oxygen carriers (sometimes involving the use of rare earths such as lanthanum, cerium and yttrium (Cao, Sit, & Pan, 2014;Chen, Galinsky, Wang, & Li, 2014)) or enhanced Ca looping materials. For steam reforming with natural gas and the use of fixed-bed technology, such approaches may be justifiable.…”