Role of potassium in the enhancement of the catalytic activity of calcium oxide towads tar reduction
Journal article, 2018

Gasification in fluidized bed systems is considered to be a highly promising alternative for the thermal conversion of biomass. A major challenge for this process is the formed tars, which represent a loss of energy from the product gas and entail additional costs for their removal. Olivine is considered to be the most effective catalytic bed material in terms of its impact on tar levels in the product gas. Additions and modifications to olivine have revealed the potential to enhance its catalytic activity. In the present study, the effect of the addition of K2CO3 to the gasification process on the tar decomposition capability of olivine were evaluated. The effect of the added K2CO3 on the product gas was assessed in the 30-MWth pilot gasification plant GoBiGas. Once decreases in the tar level were detected, samples of the bed material were extracted from the system and evaluated for morphological and chemical changes related to the observed catalytic effect. SEM-EDX and XPS analyses of the surfaces of the olivine particles indicate that the additive is involved in the formation of mixed oxides of Ca and K within the outermost layer of the olivine particles. DFT modeling showed that the formation of mixed Ca and K oxides changes the oxidation potential of the surface, which may explain the increased activity of ash-coated olivine towards tar reduction.

Author

Pavleta Knutsson

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

Valentina Cantatore

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

Martin Seemann

Chalmers, Space, Earth and Environment, Energy Technology

Eric Tam

Chalmers, Industrial and Materials Science, Materials and manufacture

Itai Panas

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

Applied Catalysis B: Environmental

0926-3373 (ISSN) 1873-3883 (eISSN)

Vol. 229 5 88-95

Subject Categories

Production Engineering, Human Work Science and Ergonomics

Atom and Molecular Physics and Optics

Environmental Sciences

DOI

10.1016/j.apcatb.2018.02.002

More information

Created

4/16/2019