Biomass gasification bottom ash as a source of CaO catalyst for biodiesel production via transesterification of palm oil

Published Date
1 March 2015, Vol.92:234–243, doi:10.1016/j.enconman.2014.12.057

Author 

• Thawatchai Maneerung ^a
• Sibudjing Kawi ^b,,
• Chi-Hwa Wang ^a,b,,

• aNUS Environmental Research Institute, National University of Singapore, 1 Create Way, Create Tower #15-02, Singapore 138602, Singapore
• bDepartment of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117576, Singapore

Received 28 October 2014. Accepted 18 December 2014. Available online 8 January 2015. 

Highlights 

• CaO catalyst was successfully developed from wood gasification bottom ash.
• •
  CaCO₃ in bottom ash can be converted to CaO catalyst by calcination.
• •
  CaO catalysts derived from bottom ash exhibited high activity towards transesterification.
• •
  CaO catalysts derived from bottom ash can be reutilized up to four times.

Abstract 

The main aim of this research is to develop environmentally and economically benign heterogeneous catalysts for biodiesel production via transesterification of palm oil. For this propose, calcium oxide (CaO) catalyst has been developed from bottom ash waste arising from woody biomass gasification. Calcium carbonate was found to be the main component in bottom ash and can be transformed into the active CaO catalyst by simple calcination at 800 °C without any chemical treatment. The obtained CaO catalysts exhibit high biodiesel production activity, over 90% yield of methyl ester can be achieved at the optimized reaction condition. Experimental kinetic data fit well the pseudo-first order kinetic model. The activation energy (E_a) of the transesterification reaction was calculated to be 83.9 kJ mol⁻¹. Moreover, the CaO catalysts derived from woody biomass gasification bottom ash can be reutilized up to four times, offering the efficient and low-cost CaO catalysts which could make biodiesel production process more economic and environmental friendly.

Graphical abstract

Keywords

• Biodiesel production
• Calcium oxide catalysts
• Transesterification
• Biomass gasification
• Bottom ash

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  Corresponding authors at: Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117576, Singapore. Tel.: +65 6516 5079; fax: +65 6779 1936 (C.-H. Wang). Tel.: +65 6516 6312; fax: +65 6779 1936 (S. Kawi).

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http://www.sciencedirect.com/science/article/pii/S0196890414010711