Alkali-wall interactions in a laboratory-scale reactor for chemical looping combustion studies
Journal article, 2021

Alkali metal-containing compounds are readily released during thermal conversion of solid fuels, and may have both detrimental and beneficial effects on chemical looping combustion. Here, we characterize alkali interactions with the inner walls of a laboratory-scale reactor under oxidizing, reducing and inert conditions at temperatures up to 900 °C. KCl aerosol particles are continuously introduced to the stainless steel reactor and the alkali concentration is measured on-line with a surface ionization detector. Aerosol particles evaporate at temperatures above 500 °C and KCl molecules rapidly diffuse to the reactor wall. Up to 92% of the alkali reaching the wall below 700 °C remains adsorbed, while re-evaporation is important at higher temperatures, where up to 74% remains adsorbed. Transient changes in alkali concentration are observed during repeated redox cycles, which are associated with changes in chemical composition of the wall material. Metal oxides on the reactor wall are partially depleted under reducing conditions, which allow for the formation of a new potassium-rich phase that is stable in a reducing atmosphere, but not under inert conditions. The observed wall effects are concluded to be extensive and include major transient effects depending on gas composition, and the implications for laboratory studies and improved experimental methodology are discussed.

Laboratory-scale reactor

Chemical looping combustion

Surface ionization detector


High temperature corrosion


Viktor Andersson

University of Gothenburg

Amir H. Soleimanisalim

Xiangrui Kong

University of Gothenburg

Fredrik Hildor

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

Henrik Leion

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

Tobias Mattisson

Chalmers, Space, Earth and Environment, Energy Technology

Jan B. C. Pettersson

University of Gothenburg

Fuel Processing Technology

0378-3820 (ISSN)

Vol. 217 106828

Förbränningskemi för biomassa med syrebärarmaterial

Swedish Research Council (VR) (2016-06023), 2017-01-01 -- 2024-12-31.

Subject Categories

Materials Chemistry

Other Chemical Engineering

Corrosion Engineering



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