Determination of Moisture, Volatile, and Ash in Biomass/Plant Tissue (TGA801)

Importance of the Topic

Determination of moisture, volatile matter, and ash content is fundamental for characterizing biomass and plant-based fuels. These parameters influence combustion efficiency, material handling, and disposal strategies. Accurate quantification supports fuel quality assessment, process optimization, and compliance with environmental regulations.

Objectives and Study Overview

This application note illustrates a standardized thermogravimetric analysis (TGA) method using the LECO TGA801 to measure moisture, volatile matter, and ash in biomass and plant tissue. The goal is to demonstrate method setup, sample preparation, analytical parameters, and data interpretation for reliable results.

Methodology and Procedure

Sample Preparation

• Grind samples to a uniform fineness below 1.0 mm.
• Weigh approximately 1.0 g of sample into ceramic crucibles.

Analysis Workflow

1. Set up the method in the instrument software with three sequential steps: moisture, volatile, and ash.
2. Moisture step: heat from 25 °C to 107 °C at 6 °C/min under nitrogen (10 L/min), hold 15 min.
3. Volatile step: cool, then heat from 107 °C to 950 °C at 45 °C/min under nitrogen (10 L/min), hold 7 min.
4. Ash step: cool, then heat from 600 °C to 750 °C at 3 °C/min under oxygen (3.5 L/min), hold 15 min.
5. Record mass changes at each step and calculate mass ratios for moisture, volatile matter, ash, and their dry-basis equivalents.
6. Ensure mass constancy criteria (0.0010 g window over 9 min) before final weighing.

Used Instrumentation

• LECO TGA801 macro thermogravimetric analyzer with dual furnace capability.
• Ceramic crucibles (621-331) and covers (529-048); double-ended scoop (621-011-507).
• Nitrogen and oxygen gas supply, controlled flow rates.

Main Results and Discussion

Typical analysis of alfalfa and generic biomass showed:

• Alfalfa (n=10): moisture 6.54% ±0.03, volatile dry matter 74.3% ±0.2, ash dry 10.5% ±<0.1.
• Biomass (n=10): moisture 5.75% ±0.03, volatile dry matter 80.9% ±0.1, ash dry 0.49% ±0.05.

These results demonstrate high precision across replicate batches and the effectiveness of the TGA801 for compositional analysis.

Benefits and Practical Applications

The described TGA method offers:

• Simultaneous multi-parameter analysis in a single run, reducing total analysis time (~4 hours per batch).
• High accuracy and repeatability for QA/QC in biofuel production and research settings.
• Automated data processing and customizable calculation formulas for dry-basis reporting.
• Scalable throughput with up to 19 samples per run, supporting both research and industrial laboratories.

Future Trends and Opportunities

Emerging developments in TGA and biomass analysis include:

• Integration with hyphenated techniques (e.g., TGA-GC/MS) to identify evolved gases during thermal decomposition.
• Advanced data analytics and machine learning for predictive modeling of combustion behavior.
• Miniaturized and portable TGA systems for field-based biomass characterization.
• Standardization of methods for emerging biofeedstocks and waste-to-energy applications.

Conclusion

The LECO TGA801 method provides a robust, accurate, and efficient approach for simultaneous determination of moisture, volatile matter, and ash in biomass and plant tissues. Its automation, precision, and throughput capabilities make it well-suited for industrial QA/QC and research laboratories focused on renewable fuel characterization.