Determination of Moisture, Volatile Matter, and Ash in Biomass/Plant Tissue

Significance of the Topic

The accurate quantification of moisture, volatile matter, and ash content in biomass and plant materials is essential for evaluating fuel quality and combustion performance. Moisture affects dry-basis results; volatile matter relates to energy release; ash informs material balance and disposal planning.

Objectives and Study Overview

This study presents a standardized thermogravimetric method using the LECO TGA701 for simultaneous determination of moisture, volatile matter, and ash in biomass samples including wood pulp, alfalfa, and barley. It aims to validate method parameters and demonstrate precision and accuracy across sample types.

Methodology and Instrumentation

Sample preparation includes grinding to <0.5 mm and loading approximately 1.0 g into ceramic crucibles. The thermal program comprises three sequential steps:

• Moisture: 25 °C → 107 °C at 6 °C/min under nitrogen, hold 0.25 h (total ~0.28 h)
• Volatile matter: 107 °C → 950 °C at 50 °C/min under nitrogen, hold 0.12 h (total ~0.23 h)
• Ash: 600 °C → 750 °C at 3 °C/min under oxygen, no hold (total ~0.50 h)

Component percentages are calculated relative to initial sample mass using standardized equations.

Used Instrumentation

• TGA701 thermogravimetric analyzer (LECO Corporation)
• Ceramic crucibles and covers
• Nitrogen and oxygen gas supplies
• Analytical balance (readability 0.0005 g)

Main Results and Discussion

Moisture content ranged from 3.32 % (wood pulp #2) to 9.22 % (barley). Volatile matter (dry basis) averaged 83.3 % in wood pulp and 76.7 %–79.4 % in plant tissues. Ash content was low in wood pulp (0.34 %–0.47 %) and higher in alfalfa and barley (2.13 %–8.75 %). Repeatability was high, with standard deviations below 0.3 % for moisture and volatile matter, and below 0.2 % for ash. A linear calibration (y=1x+0) is recommended for volatile matter determination.

Benefits and Practical Applications

• Rapid, reliable determination of key fuel parameters for biomass research and quality control.
• Enhanced material balance calculations for combustion and ash handling.
• Applicability to diverse plant-derived matrices in both research and industrial settings.

Future Trends and Potential Applications

Future developments may include automated sampling integration, real-time process monitoring, and coupling with mass spectrometry for evolved gas analysis. Adaptations could extend to emerging biofuel streams and waste-to-energy feedstocks.

Conclusion

The TGA701-based protocol offers a robust and precise approach for quantifying moisture, volatile matter, and ash in biomass. Its simplicity and reproducibility support broad adoption in analytical laboratories focused on bioenergy and material characterization.