Effect of torrefaction on the fuel characteristics of timothy hay

ABSTRACT

This study investigates torrefaction of timothy hay (TH) by varying torrefaction temperature, heating rate and residence time. The minimum mass yield (MY) and energy yield (EY) were found to be 51.4% and 38.0%, respectively, when the torrefaction was conducted at 300 °C, 45 min and 30 °C/min. A decrease in volatile matter and an increase in fixed carbon content confirmed that the fuel ratio (FR) increased from 0.21 in raw TH to 0.73 in the torrefied TH produced at 300 °C, 45 min and 30 °C/min. Variations in the heating rate of the reactor below 50 °C/min have less impact on the characteristics of the torrefied TH. Correlations were proposed to predict the characteristics of torrefied TH using dry solid mass loss. The decreased intensity of the O-H functional group confirms that the torrefied TH has a more hydrophobic nature. The mass loss rate of the torrefied sample produced at 300 °C peaked only at the elevated temperature of 468 °C, which indicated that severely torrefied TH has higher thermal stability. Morphological image analysis showed that torrefied TH samples have more surface porosity and structural damage compared to those found in raw TH.

KEYWORDS:

• Torrefaction
• fuel properties
• timothy hay
• fuel ratio
• thermal behaviors

Acknowledgements

The authors would like to express their sincere thanks to the Natural Sciences and Engineering Research Council of Canada (NSERC) and the New Brunswick Department of Agriculture, Aquaculture, and Fisheries (NBDAAF) for their research funding to carry out the study.

Disclosure statement

No potential conflict of interest was reported by the authors.