Role of potassium in the enhancement of the catalytic activity of calcium oxide towards 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 K 2 CO 3 to the gasification process on the tar decomposition capability of olivine were evaluated. The effect of the added K 2 CO 3 on the product gas was assessed in the 30-MWth pilot gasification plant GoBiGas. Once dec reases 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.

DFT

Catalyst

Tar reduction

Olivine

Gasification

Potassium role

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

Martin Seemann

Chalmers, Space, Earth and Environment, Energy Technology

Pui Lam Tam

Chalmers, Industrial and Materials Science

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 88-95

Subject Categories

Chemical Process Engineering

Other Chemistry Topics

Bioenergy

DOI

10.1016/j.apcatb.2018.02.002

More information

Latest update

3/8/2018 2