Biomass ash interactions with a manganese ore used as oxygen-carrying bed material in a 12 MWth CFB boiler
Journal article, 2018

Oxygen carrier aided combustion (OCAC) is a combustion concept which utilises oxygen carriers as bed material in existing fluidised bed boilers. In this study, a manganese ore was used in a 12 MWthCFB boiler. During the experimental session with the manganese ore, the boiler was operated with wood chips as fuel for more than a week without replacement of the bed material. Bed samples were extracted each day in order to investigate interactions between the manganese ore and the wood ash components. The samples were examined with SEM/EDX to follow the chemical distribution of ash elements in the bed particles. Physical properties such as density, size distribution and attrition resistance were followed as well. The impact on the reactivity of the oxygen-carrier bed particles was examined in a batch fluidised bed reactor at laboratory scale with gaseous fuels. Elemental composition analysis of the samples showed that common ash elements such as silicon, calcium, potassium, magnesium and sulphur had been accumulated in the manganese ore. Silicon, calcium and potassium were found throughout the particles as well as in formed surface layers. Sulphur was only found at the surface of the particles. The reactivity of the oxygen-carrying particles was affected during operation and showed a continuous decrease with increasing residence time in the boiler. The decrease in reactivity could be coupled to the layers of ash formed. Thus, this is an important issue when developing novel combustion concepts, such as OCAC and chemical-looping combustion (CLC), for biomass fuels.

Biomass ash

Oxygen carrier aided combustion

Manganese ore

Fluidised bed combustion


Malin Hanning

Chalmers, Space, Earth and Environment, Energy Technology

Angelica Gyllén

Chalmers, Space, Earth and Environment, Energy Technology

Fredrik Lind

Chalmers, Space, Earth and Environment, Energy Technology

Magnus Rydén

Chalmers, Space, Earth and Environment, Energy Technology

Biomass and Bioenergy

0961-9534 (ISSN)

Vol. 119 179-190

Miljövänligare och effektivare förbränning i fluidbädd med manganmalm som bäddmaterial

Swedish Energy Agency (38758-1), 2014-05-12 -- 2015-12-31.

Subject Categories

Chemical Process Engineering


Other Materials Engineering



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