Thermochemical characterisation of Acacia auriculiformis tree parts via proximate, ultimate, TGA, DTG, calorific value and FTIR spectroscopy analyses to evaluate their potential as a biofuel resource

ABSTRACT

Continuously increasing energy requirements coupled with environmental pollution have established pressure to utilise lignocellulosic biomass for energy production. Acacia auriculiformis is a fast-growing species capable of accumulating large quantities of biomass without requiring major agricultural inputs. The aim of this research was to investigate the thermochemical properties of its tree parts including phyllodes (leaves), trunk, bark and branches to utilise them as solid fuel to produce bioenergy. Thermogravimetric and derivative thermogravimetric (TGA and DTG ) analyses were performed to study the biomass degradation behaviour, which showed the decomposition of biomass in three major stages corresponding to the decomposition of hemicellulose, cellulose and lignin components. Fourier transform infrared (FTIR) analysis was carried out to determine the functional groups. Proximate analysis showed the weight percentages of moisture contents, volatile matter, fixed carbon and ash contents as 7.25–9.27%, 61.79–73.28%, 16.50–27.92% and 2.13–3.72%, respectively. Ultimate analysis showed the ranges of carbon, hydrogen and oxygen as 44.27–49.41%, 5.3–6.10% and 41.93–49.44% respectively, while lower values of sulphur and nitrogen components were reported which are encouraging from an environmental perspective. Higher heating values (HHV) for the parts were reported to range between 17.85 and 20.93 MJ/kg on a dry basis.

KEYWORDS:

• Thermochemical characterisation
• biomass and bioenergy
• Acacia auriculiformis
• FTIR spectroscopy
• thermogravimetric analysis (TGA and DTG)

Acknowledgements

This research was funded by the Brunei Research Council under project UBD/BRC/11 and was conducted with the collaboration of the Faculty of Integrated Technologies (FIT), Institute of Biodiversity and Environmental Research (IBER) and Faculty of Science (FOS), Universiti Brunei Darussalam. The first author is thankful to University Brunei Darussalam for the award of a Graduate Research Scholarship to do his PhD studies. We acknowledge the support of the Brunei Forestry Department, Ministry of Primary Resource and Tourism (MPRT), for granting the collection and entry permits, and the Biodiversity Research and Innovation Centre, MPRT, for granting us export permits. We also acknowledge the support of Ms Salwana Jafar, Ms Hadija and Ms Shamira Matali during the collection of samples and the research work.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Brunei Research Council (BRC) [grant number UBD/BRC/11 Project].