Thermochemical characterization of napier grass as an energy source and its environmental and economic benefit analysis

ABSTRACT

Using the standard methods for the determination of approximate analysis, ultimate analysis, chemical composition, heating value and inorganic elements, the thermochemical properties of three air-dried napier grass samples have been analyzed in the present study. The results showed that thermochemical characteristics of all samples were found to be similar. The energy grass obviously comprised a large percentage of volatile matter at 72.72 ± 0.73 wt%. The molar rations of hydrogen to carbon (H/C) ranging from 1.60 to 1.73 are close to those of cellulose (H/C = 1.67) and hemicellulose (H/C = 1.6), which was in accordance with its higher heating value (16.3 MJ/kg). However, the contents of nitrogen and chlorine were significantly high, suggesting that the emissions of acidic gases and chlorinated organics from biomass-to-heat facilities will arouse concern. Based on the 100,000 ha fallow farmland cultivated into the energy grass in Taiwan and the Tier 1 method recommended by the Intergovernmental Panel on Climate Change, the environmental benefit of mitigating CO₂ emissions and the economic benefit of oil equivalent were calculated to be around 5.0 × 10 ⁶ Gg/yr and 1.1 × 10 ⁷ barrels/yr, respectively.

KEYWORDS:

• Biomass energy
• economic benefit
• environmental benefit
• napier grass
• thermochemical property

Acknowledgements

The authors would like to appreciate Yu-Kuei Cheng (Livestock Research Institute, Council of Agriculture, Taiwan) for providing napier grass samples. Sincere appreciation is also expressed for the experimental assistance by Yuan-Ming Chang, Shin-Liang Kuo, Huei-Ru Chen and Sheau-Horng Lin (National Pingtung University of Science and Technology, Taiwan).