Performance of Ni/dolomite pellet catalyst on gas distribution from cassava rhizome gasification with a modular fixed-bed gasifier

ABSTRACT

Thermal conversion of cassava rhizome was performed using a modular downdraft gasifier with the addition of Ni-based catalysts as promising tar eliminating and produced gas upgrading techniques. The activities of a synthesized 5% Ni/dolomite pellet catalyst prepared by impregnation method were investigated in a secondary reactor downstream of the gasifier. High reforming activity of the Ni/dolomite pellet catalyst on tar reduction was achieved. The conversion to H₂ and CO was improved via steam reforming of methane and char reaction with CO₂. Moreover, the formation of CH₄ and C_xH_y was diminished through the tar or condensable hydrocarbon reformed on the catalyst surface. The carbon and hydrogen conversions of cassava rhizome with prepared catalyst were 83.79% and 61.78%, respectively, at an air flow rate of 1.98 m³/hr. At this condition, tar formation was low, while the lower heating value was 4.39 MJ/m³ and H₂ to CO molar ratio was 1.22. Generally, the addition of a catalyst not only enhanced gas production, but also reduced tar and particulate matter generation; thus, its implementation should help lessen the pollution control requirement and cost of operation, while allowing higher quality fuel gas production.

KEYWORDS:

• Downdraft gasifier
• cassava rhizome
• thermal conversion
• dolomite
• catalyst

Acknowledgements

The authors would like to thank the National Metal and Materials Technology Center for their help with equipment and analysis.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This research was supported by a Grant for International Research Integration: Chula Research Scholar, Ratchadaphiseksomphot Endowment Fund.