Defluidization of ilmenite, an oxygen carrier for chemical looping combustion – laboratory experiments with potassium salts

A4 Conference proceedings


Internal Authors/Editors


Publication Details

List of Authors: Maria Zevenhoven, Christoffer Sevonius, Patrik Salminen, Daniel Lindberg, Anders Brink, Patrik Yrjas, Leena Hupa
Editors: Asfaw Beyene
Publication year: 2017
Publisher: San Diego State University
Book title: 30th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems, July 2-6, San Diego, California : ECOS 2017
Start page: 1
End page: 12
ISSN: 2175-5418


Abstract

Use of biomass in Chemical Looping Combustion (CLC) and subsequent CO2 capture ideally leads to negative CO2 emissions (Bio-CLC). In Bio-CLC ash-forming matter of biomass, mainly consisting of potassium, calcium, sulfur, phosphorus, and chlorine, may interact with the oxygen carrier, causing agglomeration, and thus inhibit the chemical looping process. The detailed/exact mechanisms behind these effects are not properly understood. Ilmenite, an iron-titanium mineral, can be used as an oxygen carrier in CLC.

In this study the interactions between ilmenite and potassium compounds, typical for biofuel ashes, in a labscale furnace were investigated. Mixtures of ilmenite with different potassium compounds were thermally treated in an oxidizing environment at 850 and 950 °C. The interactions between potassium compounds and the carrier material were studied using DTA, XRD, and SEM-EDS. Thermodynamic equilibrium calculations were carried out to verify the reactions.

Finally, results from the laboratory tests were used to explain the behavior of ilmenite in the presence of salts in a lab-scale fluidized bed conversion. The bed agglomeration mechanisms depend on the potassium salt: dihydrogen phosphate or chloride glued the particles, whereas carbonate reacted with the bed particles.


Keywords

Ash interaction, Chemical Looping Combustion, Ilmenite

Last updated on 2019-17-10 at 03:10