Comparative Study: Impacts of Ca and Mg Salts on Iron Oxygen Carriers in Chemical Looping Combustion of Biomass
Journal article, 2021

Chemical looping combustion (CLC) is one of the most promising methods for carbon capture and storage (CCS). An oxygen carrier, i.e., a mineral that can be oxidized and reduced, is used to convert the fuel in the process. The produced CO2 is inherently separated from the air components that enables easier CCS. The use of biomass-based fuels is desirable since it can lead to negative CO2 emissions. On the other hand, alkali compounds from the biomass may interact with the oxygen carrier causing problems, such as deactivation of the oxygen carrier. The most common oxygen carriers contain iron, since iron-based ores and industrial waste materials are readily available and cost-efficient. Therefore, the interaction between the iron oxygen carriers and the biomass ash-forming compounds needs to be investigated. Since Ca/Mg are abundant in biomass, it is important to clarify how their compounds interact with the oxygen carrier. In this study, the effect of Ca/Mg carbonates, chlorides, nitrates, sulfates, and phosphates along with synthetic biomass-derived ash on iron oxides was investigated. Redox reactions were investigated at 950 degrees C during 5 h under both oxidizing and reducing atmospheres. The results showed that the effect of Ca/Mg salts on the oxygen carrier varied depending on the anion of the salt. Generally, the nitrate- and phosphate-based salts of both Ca and Mg showed the harshest effect regarding agglomeration of the oxygen carriers. It was shown that the Ca/Mg-based compounds interacted differently with iron oxides, which was an unexpected result.

Author

Duygu Yilmaz

Chalmers, Chemistry and Chemical Engineering, Energy and Material, Environmental Inorganic Chemistry 2

Britt-Marie Steenari

Chalmers, Chemistry and Chemical Engineering, Energy and Material, Nuclear Chemistry

Henrik Leion

Chalmers, Chemistry and Chemical Engineering, Energy and Material, Environmental Inorganic Chemistry 2

ACS OMEGA

2470-1343 (ISSN)

Vol. 6 25 16649-16660

Subject Categories

Chemical Process Engineering

Bioenergy

Environmental Biotechnology

DOI

10.1021/acsomega.1c02138

PubMed

34235337

More information

Latest update

7/28/2021